Shiv Nadar University

Cache prefetchers are essential for system performance, and reinforcement learning (RL) offers a lightweight alternative to heavy machine learning techniques for modern prefetchers. While previous work used 1-step SARSA-based RL for cache prefetching, it can struggle with complex memory access patterns. This study proposes using n-step SARSA instead of 1-step to capture broader contextual learning. We incorporate a dynamic property to reduce the use of outdated Q-values, guiding the RL agent to improve prefetching effectiveness. Our approach achieves approximately 12% better performance than non-RLbased prefetchers in multi-core setups and also outperforms previous RL-based prefetcher.

Abstract Objectives Vitiligo is an autoimmune disorder characterised by the presence of depigmented lesions on the skin. The autoreactive cytotoxic T cells at the epidermal‐dermal junction of the skin facilitate the targeted destruction of epidermal melanocytes, leading to the development of vitiligo lesions. Narrow‐band UVB (NBUVB) phototherapy is a widely used non‐invasive treatment that promotes transient repigmentation of lesions. However, the specific effects of NBUVB on skin dermal T cells in vitiligo patients remain largely unexplored. Insights into the mechanism of action of NBUVB phototherapy can guide therapies against cytotoxic T cells, enabling effective and sustained remission of vitiligo lesions. Methods Indian patients with active vitiligo lesions underwent 3 months of NBUVB phototherapy, thereby leading to successful repigmentation of vitiligo lesions. Spatial transcriptomic and histological analyses were employed to investigate the gene expression profiles of dermal T cells at the epidermal‐dermal junction, both before and after treatment. Results Comprehensive spatial transcriptome analysis of skin dermal T cells revealed that NBUVB phototherapy leads to the overall suppression of inflammatory genes and immune regulatory pathways that are upregulated in vitiligo patients before treatment. Consequently, tissue‐resident innate and adaptive immune cells significantly decrease post‐UVB phototherapy. Interestingly, we observe an increase in naïve CD4 + T cells post‐UVB phototherapy. Conclusion NBUVB phototherapy effectively suppresses the innate and adaptive immune cell populations and immune regulatory pathways while promoting an increase in naïve CD4 + T cells. These findings underscore a previously unrecognised immunomodulatory role of NBUVB phototherapy in vitiligo patients.

The development of water-stable metal halide perovskites (MHPs) presents a significant challenge for advanced materials and their application in electrochemical energy conversion and storage. Understanding the electronic structure of MHPs, considering electrocatalysis under an aqueous electrolyte, is essential for its widespread applications. Also, considerable efforts have been devoted to enhancing water stability through ligand passivation, compositional engineering, and surface encapsulation strategies. However, the long-term stability and charge transport properties of these materials may still fall short of expectations. Therefore, synthesizing intrinsically stable MHPs is crucial for their use in energy conversion and storage applications. Numerous comprehensive reviews have addressed the optical properties, regulation of electronic properties, and stability of MHPs. This review aims to provide an in-depth analysis of electronic structure and properties, followed by theoretical and experimental evidence of degradation mechanisms in aqueous media of various organic and inorganic MHPs. Subsequently, we also highlight the perspectives and progress in MHPs designing strategies and the synthesis of intrinsically water-stable perovskites to overcome stability challenges. By connecting the degradation dynamics with synthesis approaches for water-stable MHPs, this report paves the way for their application in electrocatalysis and energy storage devices.

Resistance spot welding (RSW) is widely utilized in the automotive and manufacturing industries for joining high-strength materials such as AISI 420 martensitic stainless steel (MSS). However, MSS spot welds exhibit low fracture toughness due to the formation of a brittle martensitic microstructure in the fusion zone (FZ), impairing weldability. This study investigates the influence of two distinct welding strategies: the weld nugget forming strategy (WNFS) and the weld nugget in-situ tempering strategy (WNTS) to enhance joint performance and mitigate these challenges. A Box-Behnken design of experiments was adopted to systematically vary weld current, weld time, and electrode force on weld quality. Weld quality was assessed using nugget diameter, peak load, and absorption energy. Tensile-shear strength, microhardness profile, and fatigue life were evaluated to characterize mechanical behavior. The microstructural analyses were conducted using optical microscopy (OM), field emission scanning electron microscopy (FESEM), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD) to characterize the phases and morphological features of the welded regions. Analysis of Variance was conducted to evaluate the significance level of the welding parameters. Furthermore, the Teaching-Learning Based Optimization (TLBO) algorithm was employed to identify the optimal parameter set. Fatigue testing (R = 0, 10Hz) showed that within the tested range of post-weld tempering durations, the in-situ tempering strategy (WNTS) provided improved fatigue life, with a maximum of 8885 cycles achieved at a tempering time of 0.36s. However, extending the tempering duration to 0.44s reduced fatigue resistance due to over-tempering effects, indicating that further work is needed to generalize these findings across different loading frequencies and materials. This work proposes an optimized RSW strategy advancing the weldability of AISI 420 MSS for structuring demanding applications through data-driven optimization.

FeSe2/rGO nanohybrids were prepared via in situ one-pot synthesis using the hydrothermal method and were assessed for their potential for peroxidase-like activity. Structural and morphological analysis using FE-SEM and TEM confirmed the successful in situ growth and uniform distribution of FeSe2 NPs onto the rGO nanosheet matrix. Furthermore, the FeSe2/rGO nanohybrids showed superior and enhanced peroxidase-like activities compared to the bare FeSe2, as demonstrated using two substrates, 3,3',5,5'-tetramethylbenzidine (TMB) and o-phenylenediamine (OPD). Michaelis-Menten kinetics showed a significantly lower Km of 0.00952 mM for TMB and 7.62 mM for H2O2, along with a high Vmax of 6.48 × 10-8 M s-1 (TMB) and 1.706 × 10-6 Ms-1 (H2O2) for FeSe2/rGO, outperforming bare FeSe2 and several other reported nanozymes. The kinetic parameters showed a strong substrate affinity and improved catalytic efficiency. Mechanistic study using terephthalic acid (fluorescent probe) revealed that •OH is majorly responsible for substrate oxidation, which is significantly enhanced by the synergistic effect of FeSe2 and rGO. Furthermore, in support of our experimental results, molecular docking studies with multiple peroxidase proteins also showed significantly higher binding affinities for FeSe2/rGO (-9.9 to -11.9 kcal mol-1), as compared to FeSe2 (-4.8 to -9.1 kcal mol-1). Overall, this work highlights FeSe2/rGO as a robust peroxidase mimic and efficient nanozyme with strong potential for colorimetric sensing and catalytic performance.

Extracellular vesicles (EVs) provide a rich source of cancer biomarkers that reflect the molecular state of their parent cells and offer strong potential for non-invasive diagnosis.Here, we report a bio-silent azide-based Fourier transform infrared (FTIR) spectroscopic strategy for the simultaneous detection of two colorectal cancer (CRC) EV surface glycoproteins, carcinoembryonic antigen (CEA) and cadherin-17 (CDH-17).EVs isolated from multiple CRC cell lines and a non-cancerous control were comprehensively characterized and analyzed by FT-IR spectroscopy.Distinct biochemical signatures in lipid, protein, carbohydrate, and nucleic acid regions enabled robust differentiation between CRC-derived and control EVs, supported by multivariate and machine-learning analyses with high classification accuracy.To achieve biomarker-specific detection, CEA and CDH-17 were selectively labeled via biotinylated antibodies followed by streptavidin-azide, generating a characteristic azide vibrational signal in the bio-silent infrared region (2000-2300 cm) without perturbing native EV spectra.Quantitative analysis of the azide signal revealed significantly elevated CEA and CDH-17 expression in CRC EVs, consistent with flow cytometry validation.Density-of-states overlap, cosine correlation, and non-negative least squares regression enabled deconvolution and simultaneous quantification of dual biomarkers from mixed samples, revealing cell line-specific expression patterns and enabling EV subtyping.This work establishes azide-FTIR spectroscopy as a rapid, label-efficient, and scalable platform for multiplexed EV biomarker detection, highlighting its promise for future liquid biopsy-based cancer diagnostics.

Visible light-responsive CdFe2O4 photocatalysts were synthesized via a one-step combustion route using a series of structurally distinct carboxylic acid-based fuels, enabling deliberate modulation of nanostructure and optoelectronic properties. The functional groups and molecular architecture of the fuels played a crucial role in governing combustion behavior, which in turn dictated crystallite growth, surface morphology, and bandgap tuning in the resulting CdFe2O4 nanoparticles. These tailored photocatalysts were evaluated for malachite green (MG) degradation in a Vis-light/CdFe2O4/H2O2 system, exhibiting pseudo-first-order kinetics with apparent rate constants enhanced by up to 31-fold as a function of solution pH. MG degradation proceeded via reactive oxygen species (ROS), including h⁺, ·OH, and O2⁻·, with h⁺ identified as the dominant oxidative species. The system showed strong pH responsiveness and sensitivity to inorganic salts ions, attributable to fuel-dependent adjustments in surface charge and morphology. Furthermore, the CdFe2O4 displayed excellent stability, retaining high photocatalytic activity over nine consecutive reuse cycles.