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Erratum: “Photoluminescence Emission Efficiency Analysis Methodology by Integrating Raman Spectroscopy of the A1(LO) and E2(high) Phonons in a GaInN/GaN Heterostructure” [Physica Status Solidi B, 2024, 2400057]
No full textThere was a mistake in solving Equation 4a.4a (Formula presented.) 4b (Formula presented.) We show corrected Figure 11 and, resultantly, related Figures 13, and 14. Areas marked with asterisks and circles in Figure 11a are discussed in conjunction with Figure 14. We reconsider and revise the carrier recombination process. The temperature increase was obtained using the shift in the E2(high) mode energy (EE2H) by increasing laser power from zero to 9 mW. EE2H at the zero-power limit was given by the intersection of the linear function fitted to the dependence of the experimental plots. 11 Figure (Figure presented.) Examples of images of temperature increase in the Ga0.95In0.05N layer obtained from ΔEE2H using the parameter sets (a, b) for GaN of (−1027, −597): a) and (−742, −715): b). 13 Figure (Figure presented.) Histogram of effective LOPC+ energy shift by irradiating the 9 mW laser, a) (a, b) = (−1027, −597), b) (a, b) = (−911, −852), and (c) (a, b) = (−742, −715) for GaN. The negative values occupy 10%, 25%, and 40% of pixels in the images of ΔELOPC for (a), (b), and (c) respectively. 14 Figure (Figure presented.) Mapping images of ΔELOPC when increasing the laser power to 9 mW, a) for (a, b) = (−1027, −597) and b) for (a, b) = (−742, −715) for GaN, c) ne, and d) PL emission intensity per electron when using (a, b) = (−1027, −597). In the published article, we described that the increase in the Raman peak energy of the LO phonon–plasmon coupling (LOPC) mode by increasing the laser power (ΔELOPC) was negative in 47% of the measured region when taking the deformation potentials set (a, b) = (−742, −715) for GaN. In the revised images, 40% region was found to have negative values. When using (a, b) = (−1027, −597), the negative value region occupies 14%. The revised Figure 13 shows that the region with negative ΔELOPC values increases as a value decreases. The parameter set of (a, b) = (−1027, −597) is recommended for GaN by a statistical consideration of the inclusion of an unreliable negative value area as stated in the published paper. Figures 14a,b show the revised images of the distribution of ΔELOPC. In Figure 14c, the mapping image of ne for (a, b) = (−1027, −597) is exhibited, where the center region has a high electron density, which is the same property as shown in the previous version. The corrected PL emission efficiency IPL/ne shown in Figure 14d in this region is lower than the values in the surrounding area. This is the same feature as published. Figure 6a suggests the higher ΔEE2H in the center region, but the contrast in ΔT obtained from the EE2H at the zero-power limit is ambiguous. This is attributed to the high uncertainty of ΔT (σΔT) as shown in Figure 15, which is obtained from the uncertainty of the slope of the fitted linear function of EE2H. On the other hand, the regions with extremely high and low ΔT areas marked in Figure 11a show a correlation with IPL/ne in Figure 14d, excluding the regions at (x, y) = (2.5, 0.4), (0.4, 0), and (0, 0). At (2.5, 0.4), σΔT is significantly high. At (0.4, 0), ΔELOPC is negative. Thus, we can exclude these regions from the discussion. The point of (0, 0) has a low σΔT and a positive ΔELOPC, and thus there is no reason to exclude this point. As ne at this point is lower than that in the center region, the nonradiative recombination rate is possibly higher, while the emission efficiency is not so low. At present, we have no clear reason for this point. However, the low rate of carrier escape from this region and high nonradiative recombination rate possibly affect it. Further analysis of carrier transport using Boltzmann equation is considered to be required. For other regions of extremely high and low ΔT, the correlation is good. In conclusion, even though the unclear correlation between ΔT and IPL/ne at a glance because of the high uncertainty of ΔT, the correlation is identified for the regions with extremely high and low ΔT regions beyond the uncertainty. It is considered that temperature increase takes place in the region of low PL emission efficiency. 15 Figure (Figure presented.) Uncertainty of temperature increase. This method allows us to discuss local carrier dynamics by integrating PL emission efficiency as the intensity per electron, temperature increase related to local nonradiative carrier recombination, the potential energy of carriers, strain, and alloy composition
Engineering Scintillator Materials: From Interfacial dynamics to high resolution X-ray imaging screens
No full textTechnological advancements have long been intertwined with material innovations. In the realm of X-ray imaging, scintillation energy donor-acceptor molecular systems hold considerable promise for enhancing scintillator performance. These systems with efficient energy transfer processes are essential for improving both X-ray absorption and light emission along with a control over excited-state dynamics, ultimately leading to superior imaging resolution. This methodology has significant implications for the design and optimization of various light conversion devices, particularly X-ray imaging scintillators.
This dissertation explores the development and enhancement of scintillator materials through the innovative application of thermally activated delayed fluorescence (TADF) chromophores. TADF chromophores facilitate delayed fluorescence via reverse intersystem crossing, thereby enabling the effective utilization of both singlet and triplet excitons. Our findings highlight significant advancements in X-ray sensitivity and radioluminescence intensity achieved through the strategic interplay between distinct TADF systems, leveraging simultaneous singlet-singlet and triplet-triplet energy transfer mechanisms. In addition to organic TADF-based scintillators, this research extends the framework to hybrid scintillators by integrating TADF materials with inorganic [ZnS(Ag)] components. This combination has yielded substantial improvements in sensitivity and spatial resolution, illustrating the synergistic benefits of hybrid material systems.
Furthermore, the exploration of organometallic scintillators reveals their remarkable capabilities, offering 100% exciton utilization efficiency and unity intersystem crossing (ISC), which together enable outstanding X-ray radioluminescence performance even at low temperatures. The main goal of this dissertation is to advance scintillator materials through a synthesis of molecular engineering and innovative energy transfer strategies, ultimately enhancing X-ray imaging screen performance. To conclude, the research highlights the transformative potential of TADF molecular systems in scintillation applications, signaling a shift toward next-generation high-performance imaging technologies. It contributes to the evolution of X-ray scintillation and underscores the significance of these advancements across various applications
Synthesis, crystal structural description, DNA binding, molecular docking, and anticancer evaluation of the novel platinum(IV) supramolecular complex.
No full textA novel platinum(IV) supramolecular complex; [PtCl2(2,2'-bipy)2](PtCl6) was synthesized in aqueous acetonitrile solution at ambient temperature with constant stirring. The structure was confirmed by elemental analysis, FT-IR, UV-vis, NMR spectroscopy, and single-crystal X-ray diffraction, revealing a unique distorted octahedral geometry and a three-dimensional network stabilized by hydrogen bonding and π-π stacking. DNA binding studies, including electronic absorption titration and viscometry, indicated a groove binding mechanism with a binding constant (Kb) of 5.00 × 10⁶ M-1. Molecular docking with DNA (PDB ID: 1BNA) and cancer-related proteins (PDB codes: 3ig7, 3eqm, 4fm9) supports these interactions, while in vitro anticancer assays demonstrated potent cytotoxicity with IC₅₀ values of 41.37 μM for HepG2, 47.62 μM for HCT116, and 73.90 μM for MDA-MB-231 cells, outperforming cisplatin in selectivity. This study not only advances our understanding of structure-activity relationships in platinum-based complexes but also highlights the potential of this complex as a promising candidate for developing more effective and less toxic anticancer agents.This project was funded by the University of Jeddah, Jeddah, Saudi Arabia, under grant No. (UJ-24-DR-3065-1). Therefore, the authors thank the University of Jeddah for its technical and financial support.This work was funded by the University of Jeddah, Jeddah, Saudi Arabia, under grant No. (UJ-24-DR-3065-1). Therefore, the authors thank the University of Jeddah for its technical and financial support
Assessing Scale and Predictive Diversity in Models for Single-Cell Transcriptomics based on Geneformer
No full textFoundation models are increasingly applied to single-cell transcriptomics, where they promise to capture generalizable representations that support diverse downstream analyzes. However, two central questions remain: Does scaling pre-training data reliably improve performance, and do models trained on rank-ordered expression profiles confer advantages for mitigating batch effects? We addressed these questions by systematically assessing transformer-based models pre-trained on ranked single-cell profiles with varying data scales. The models were evaluated on masked gene prediction and downstream tasks, including cell type classification, perturbation response prediction, and zero-shot batch integration. To complement prediction accuracy, we further quantified prediction repetition, uniqueness, and diversity. In addition, we evaluated architectural refinements that incorporate cumulative prediction adjustment and similarity-based regularization; however, the study mainly focused on comparative benchmarks rather than the development of new models. Our results indicated that scaling pretraining corpora improved masked prediction accuracy but did not consistently enhance downstream performance. Smaller models often matched or exceeded larger ones, indicating diminishing returns relative to scale. Rank-based models offered limited robustness to batch effects and consistently underperformed relative to domain-specific correction methods. Across all scales, high redundancy in predicted genes remains a major limitation. Together, these findings challenge assumptions that larger datasets or rank-order modeling automatically confer stronger generalization. Progress in single-cell foundation models may depend less on scale and more on pre-training objectives that enhance predictive diversity and biological plausibility.We would like to acknowledge Xin Gao and Jesper Tegn´er for their valuable feedback and constructive discussions that helped strengthen this study. We would also like to 388 389 390 391 392 393 thank the Department of Biostatistics and Bioinformatics at Duke University for their 394 collaborative insights and the KAUST Supercomputing Core Laboratory for providing 395 essential computational resources used in model pretraining and large-scale analysis.
This work was supported by the Smart Health Initiative and baseline-funding from the 398 King Abdullah University of Science and Technology (KAUST)
Nocturnal fish chorusing activity in the central Red Sea mesophotic reef zone and adjacent shallow sites
No full textThrough sharing characteristics of chorus activity, especially in regions that are particularly data deficient, we can aim at a broader, global understanding of fish chorusing and consequently important spatiotemporal changes in habitat use by schooling fish. Here, we identify seasonal changes in fish chorusing activity using passive acoustic monitoring, in the central Red Sea mesophotic and adjacent shallow coral reef zones. For this study, recorders were placed in the mesophotic coral reef zone (70–80 m), and adjacent shallow reef sites (10 m), over 2 weeks during summer and winter seasons. A total of eleven choruses were identified and catalogued according to timing, location and acoustic characteristics of frequency and sound pressure levels. The presence of choruses in both deep and shallow reef sites is indicative of critical habitat for fish foraging, courtship, spawning, and/or migratory activity. All but two choruses were found to originate at or near the mesophotic sites. Four choruses unique to summer and winter (n=3 and 1 respectively) were most prevalent in soundscapes. Temperature and oxygen levels, measured to document conditions under which the choruses were present, showed little change across the mesophotic zone even between seasons, while daily fluctuation occurred in the adjacent shallow sites in both seasons.The author(s) declare that financial support was received for the research and/or publication of this article. This research was funded
by baseline funding by King Abdullah University of Science and Technology provided to CD and FB.We thank the CMR staff, especially Andres Espinoza, Ramzi S. Al-Jahdali, and David Atienza for invaluable help in deployment
and troubleshooting gear, as well as CMR skippers Mohammed Y. Alsheik, Issam Al-Jahdali, Eleazar G. Gonomit, Walid Al-Jahdali,Gazi Al-Jahdali, Abdullah Al-Jahdali; and fieldwork assistance from Nayra Pluma-Guerrero and Jennifer Thompson. We also thank Vanita Dighe and Eleonora Re for help with water sample analysis, as well as Miles Parsons for initial advice on fish choruses and using CHORUS, and Jennifer Miksis-Olds for initial discussion on identifying currents, anthropogenic noise and artefacts within soundscapes. Lastly (but certainly not least), thank you to both reviewers and Editor Lucia Di Iorio, whose valuable comments and advice helped improve the manuscript greatly. During preparation of the manuscript, ChatGPT (4o) was used to draft some of the code utilized in the work, as well as improve the readability of some paragraphs. All work was subsequently reviewed by the author/s, who take full responsibility for the content of the published article
Computation-assisted design of stable quasi-2D organic sulfate perovskite NIR light-emitting diodes
No full textQuasi-two-dimensional (2D) perovskite light-emitting diodes (PeLEDs) exhibit high red-emission efficiency but poor stability due to defect-mediated recombination and ion migration in hybrid perovskite nanocrystals (NCs). Here, we present a solvent-free mechanochemical synthesis of red-emitting quasi-2D (OA)2(MA)2Pb2I8(PbSO4) NCs using dioctylammonium sulfate (DOS), guided by first-principles calculations. The DOS ligand promotes PbSO4 layer formation, which passivates defects, suppresses ion migration, and enhances humidity resistance. Unlike iodide-based octylammonium iodide (OAI) devices that degrade rapidly and emit only at 763 nm, DOS-stabilized PeLEDs show dual emission at 651 and 763 nm, indicating improved phase stability. The devices achieve a peak luminance of 7,039 cd/cm2 and an external quantum efficiency of 9.76%, retaining over 60% of initial EQE after 100 days, markedly outperforming conventional OAI-MAPbI3 PeLEDs (<20%). These results demonstrate that sulfate passivation provides a simple and scalable route to robust, durable red-emitting quasi-2D PeLEDs, offering a promising strategy for high-performance optoelectronic devices.This work was supported by the National Research Foundation (NRF) of Korea ( BrainLink RS-2023-00236798 )
Structural substitutions on the methoxybenzene ring retain the biological activity of the zaxinone mimics MiZax3.
No full textThe plant growth regulator zaxinone is essential for proper rice growth and development. Additionally, zaxinone and its two synthetic mimics, MiZax3 and MiZax5, have been shown to significantly promote crop growth and reduce infestation by the root parasitic plant Striga by suppressing strigolactone (SL) production, highlighting their potential for field application. Here, we developed 4 new MiZax through structural modifications of the methoxybenzene ring in MiZax3 and evaluated their effects on plant growth and SL exudation. These newly developed mimics enhanced rice growth and reduced SL release without compromising the bioactivity of the lead compound MiZax3. Our findings underscore their potential to guide future chemical design efforts aimed at exploring zaxinone biology.We sincerely thank the support from the members of KAUST Analytical Core Lab and the Bioactives lab.The author(s) declare that financial support was received for the research and/or publication of this article. This work was supported by the Gates Foundation grant (OPP1136424 and INV-063191) and baseline funding from King Abdullah University of Science and Technology given to S. A.-B
Detection of biomolecular interactions using polyfluorine tracers in diffusion ordered spectroscopy
No full textBiosensor technology has emerged as a significant contributor across various sectors, including military applications and healthcare. Nonetheless, these fields encounter numerous challenges, such as the detection of low-concentration protein complexes in biological samples and an insufficient understanding of protein interaction properties. To tackle these challenges, we have introduced an alternative method that involves calculating the diffusion coefficient using Diffusion Ordered Spectroscopy (DOSY) as a transducer. This technique facilitates the detection of interactions between molecules, such as proteins, by assessing the diffusion coefficient before and after their interaction, using a tracer molecule. A polyfluorine tracer, specificallys pentadecafluorooctanoyl, was employed to investigate the avidin–biotin interaction through DOSY, enabling the calculation of the diffusion coefficients for biotin-pentadecafluorooctanoyl before the interaction and for the avidin–biotin-pentadecafluorooctanoyl complex following the interaction. The measured diffusion coefficients were 1.937 × 10−8 m2 s−1 (unbound) and 1.12 × 10−11 m2 s−1 (bound). As expected, the unbound species exhibited a significantly higher diffusion coefficient than the bound complex, consistent with the larger size and slower motion of the macromolecular assembly. Thus, the differences in these diffusion coefficients are attributed to changes in molecular weight and size, thereby confirming the avidin–biotin interaction. Additionally, the hydrodynamic radius of the avidin–biotin-pentadecafluorooctanoyl complex was determined from its diffusion coefficient, yielding a radius of 23 Å, which closely aligns with the radius of native avidin reported in existing literature. This demonstrates the method's capability to ascertain structural parameters. The application of polyfluorine tracers facilitated the acquisition of accurate and specific results without the need for a secondary antibody or further purification steps.The RSPU general facilities of the Faculty of Science, Kuwait University, supported by research grants GS01/05, GS01/03, GS03/01, and GS02/01, are greatly appreciated
Adaptive Beamwidth Control for Terahertz Drone Communications: A Row-Selective Antenna Array Approach
No full textEven though Terahertz (THz) band is promising for Drone-to-Drone (D2D) communication, there exists significant challenges, primarily high path loss and the sensitivity of directional links to mobility-induced beam misalignment. In this paper, we propose a novel adaptive beamwidth control system for THz D2D communication by activating rows of the designed 8×8 microstrip patch antenna array operating at 272.5 GHz. The proposed row-selective activation mechanism provides dynamic adjustment of the elevation beamwidth by activating different combinations of antenna rows (from 1×8 to 8×8 configurations). The proposed mechanism offers a flexible trade-off in its beam characteristics, utilizes narrow, high-gain beams to maximize performance in stable links, and dynamically switches to wider, more robust beams to ensure connectivity during drone maneuvers. The performance of the reconfigurable array is evaluated through real drone mobility traces. Simulation results reveal that during periods of misalignment, the adaptive beamwidth strategy maintains link capacity that is up to three orders of magnitude higher than fixed-beam configurations, promising a practical solution for resource-constrained THz D2D communication
Investigation of staging techniques for hydrocarbon-assisted ammonia flames in a novel dual-stage combustor
No full textAmmonia presents itself as a high-hydrogen dense and carbon-free alternative for industrial heating, power generation, and transportation. Nevertheless, the challenges of its low flame speed and elevated NOx (nitrogen oxides) emissions pose significant challenges in combustor applications. This study investigates a novel two-stage burner employing a radial injection staging technique and explores various NOx reduction strategies for hydrocarbon-assisted ammonia flames. These strategies include premixing, fuel staging, balanced fuel staging, air staging, and sequential premixing. The focus is on LPG (liquid petroleum gas)-stabilized ammonia flames. The experiments are conducted at a constant thermal input of 20 kW (10 kW LPG + 10 kW NH3), with global equivalence ratios ranging from 0.7 to 1.4. This approach aims to provide valuable insights into the effectiveness of different staging strategies for NOx reduction in ammonia combustion. Experimental analysis is undertaken to ascertain the flame stabilization, flame temperature and its reaction zone, intermediate species and major emissions like NOx and NH3 of the burner. Staging configuration strongly influenced flame stabilization, heat release distribution, and thermal field, with downstream-shifted combustion zones lowering peak temperatures and NOx formation. Among the tested strategies, fuel staging and sequential premixing consistently achieved the greatest NOx reduction across the entire operating range compared to the premixed baseline, without compromising flame stability. Chemical kinetics analysis further reveals the dominant NO formation pathways, highlighting the key roles of HNO and NHi radicals. Additionally, this analysis helps identify dominant reaction routes and the role of intermediate species in NO formation and reduction processes. The combined experimental and kinetic insights provide a mechanistic basis for optimizing staged combustion of ammonia-hydrocarbon blends for lower NOx emissions.The authors would also like to acknowledge the IIT Kharagpur, India for providing computational facilities in the Computational Fluid Dynamics (CFD) laboratory at the Department of Mechanical Engineering