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Photochemistry and Photobiology

Wiley

Preprints posted in the last 7 days, ranked by how well they match Photochemistry and Photobiology's content profile, based on 10 papers previously published here. The average preprint has a 0.01% match score for this journal, so anything above that is already an above-average fit.

1
Optimizing Signal Acquisition and Chemometric Pipelines for Micro NIR Plant Identification: Evaluating Spectral Backgrounds and Data Processing in Herbarium Specimens

Alves, T. C.; de Gasper, A. L.

2026-07-07 ecology 10.64898/2026.07.07.736730 medRxiv
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Premise: Rapid and accurate plant species identification is a critical challenge exacerbated by the taxonomic impediment. Although portable near-infrared (Micro NIR) spectroscopy represents a promising solution, the current absence of standardized protocols and a fundamental understanding of how critical acquisition and analysis parameters influence accuracy remain significant barriers. This study focused on the systematic optimization and validation of a comprehensive workflow designed to maximize the reliability of plant identification using this technology. To ensure methodological robustness across diverse foliar matrices, four vascular plant species were strategically selected as a representative test set to encompass morphological extremes, including significant variations in leaf thickness, pubescence, and surface texture. Methods: Using a portable spectrometer on herbarium specimens (exsiccate) of four vascular plant species, we systematically tested five spectral backgrounds, seven pre-processing methods, and four classification models. Subsequently, we optimized the number of spectral readings and evaluated the influence of the leaf scanning surface (adaxial vs. abaxial) on model accuracy. Results: The highest-performing combination was a Shiny Aluminum background, Second Derivative pre-processing, and a Random Forest model, which achieved a mean cross-validated accuracy of 99%. An average of just three spectral readings from the adaxial (upper) leaf face was sufficient to saturate model performance, proving statistically superior to other approaches (p < 0.001). Discussion: This study establishes a validated, high-accuracy protocol for plant species identification from herbarium specimens using portable NIR, offering a powerful tool for biodiversity studies. Direct applicability to fresh plants in the field requires future validation to account for the spectral influence of moisture variability.

2
Research protocol for a multidimensional environmental and health impact study of petrochemical plant emissions in Calvert city, Kentucky

Huntington-Moskos, L.; Cave, M.; Reynolds, L.; Anderson, L.; Housman, B.; Abolins-Abols, M.; Fratzke, R.; Holm, R.; Smith, T. R.

2026-07-09 occupational and environmental health 10.64898/2026.07.07.26356427 medRxiv
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While exposure to volatile organic compounds such as ethylene dichloride and vinyl chloride monomer is a well-established cause of liver disease, particularly hepatic hemangiosarcoma, characterizing real-world exposure profiles in communities surrounding industrial centers remains challenging. Calvert City, Kentucky (population ~2,500), provides a unique setting characterized by both active industrial emissions and legacy sources of air toxics. To address these complexities, this method paper describes the framework for the Biomonitoring and Environmental Assessment for Community Outreach and Neighborhood Safety (BEACON) study. By utilizing a novel, multi-dimensional exposure assessment strategy, BEACON aims to characterize air toxic exposures and provide actionable data for community health and safety. For the BEACON study, we will leverage Kentucky Department of Air Quality measures of air toxics, analyze urine samples in a small cohort of community volunteers, analyze community urine via wastewater in an adjacent community, geocode citizen odor reporting, assess blood markers in wildlife, survey small and large animal veterinarians in the area for anomalies in morbidity and mortality, and work with the regional health system to enhance vigilance for health issues associated with toxicants present in the area. In addition, blood samples will be collected at three time points and biobanked for future analyses. Efforts will be made to link this study to additional large-scale long-term cohorts where possible. Throughout the project, community engagement will play a critical role by raising awareness, fostering collaboration, and ensuring that the voices of affected residents are heard.

3
Spectral characterisation of short-wave infrared (SWIR) tissue chromophores and tissue-mimicking phantom optical properties

Watt, M. J.; Malouf, L.; Tao, R.; Racicot, I.; Else, T. R.; Groehl, J.; Bohndiek, S. E.

2026-07-07 bioengineering 10.64898/2026.07.07.736740 medRxiv
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Short-wave infrared (SWIR) sensors promise to expand the capabilities of optical sensing technologies but the lack of robust data characterising tissue-constituent optical properties in the SWIR makes instrument design challenging. We characterise and evaluate the optical properties of the dominant chromophores in tissue and tissue-mimicking phantoms, from visible to SWIR wavelengths. Using single-integrating sphere systems, we measured the optical properties of single-component chromophores (H2O, haemoglobin, corn oil, synthetic melanin) and multi-component tissues (whole blood, lard), to decouple contributions from optical scattering, H2O absorption and other contributing chromophores; we also characterised commonly-used phantom materials and investigated their potential to mimic soft tissues in the SWIR range using simulations. We provide a consistent dataset of absorption and reduced scattering coefficients that characterise the dominant tissue chromophores from 450 nm out to 1600 nm. These results were shown to be consistent with literature data, where available. We integrate these data into an open-source Python toolkit, SIMPA, for optical modelling and demonstrate soft tissue simulations that can be probed continuously from visible to SWIR wavelengths. Our findings are compared with tissue-mimicking phantoms, highlighting a need for additives for polymer-based phantoms that mimic SWIR water absorption. By providing this open-source dataset, we aim to enable future studies exploring SWIR light-tissue interactions that facilitate rapid assessment and prototyping of next-generation spectroscopy and imaging techniques.

4
Improving coral oxidative stress assessments through compartment-specific lipid peroxidation measurements and increased methodological standardization

Mastorakos, S. W.; Kruger, A. J.; Roger, L. M.; Carbonne, C.; Sawall, Y.

2026-07-09 biochemistry 10.64898/2026.07.08.737270 medRxiv
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Lipid peroxidation (LPO) is widely used as a biomarker of oxidative stress in coral bleaching research, yet its measurement remains poorly standardized across the field. A systematic review of the coral LPO literature reveals substantial variation in methodological approaches, including tissue fraction analysis, lysis protocols, assay choice, and normalization metrics, confounding cross-study comparison and obscuring the biological interpretation of results. We experimentally investigate two key sources of variation: the use of bulk holobiont vs separated host and algal symbiont fractions, and the choice of normalization metric. To do so, we used Montastraea cavernosa (n = 6 colonies) exposed to ambient (28C), heat stress (30.5C), and heat stress + artificial upwelling (AU; heat stress intermitted by daily pulses of cooler water, 30.5/27.5C) conditions in a controlled mesocosm experiment. Using a TBARS-based MDA assay with a lysis buffer optimized for coral tissue, we measured LPO separately in coral host and algal symbiont fractions across four time points throughout the day. Host MDA remained stable across all treatments and time points, consistent with either sufficient antioxidant buffering capacity or thermal acclimation over the experimental period. Algal symbiont MDA, in contrast, exhibited pronounced diel and treatment-specific dynamics, and the two fractions responses were decoupled from one another. Normalizing MDA to coral surface area instead of total protein content produced largely consistent diel and treatment patterns, but the two metrics diverged at specific time points, indicating that normalization choice is not interchangeable and can itself affect interpretation. Together, our literature review and empirical results demonstrate that host and algal symbiont LPO dynamics are not comparable when aggregated and argue for host-symbiont fraction separation and consistent, explicitly reported normalization as minimum standards for interpretable and cross-comparable coral LPO measurement.

5
Mechanistic characterization of tenuazonic acid-induced cellular stress responses in human esophageal KYSE-510 cells

Grgic, D.; Jobst, M.; Pais, M.; Waesoh, N.; Hager, S.; Del Favero, G.; Marko, D.

2026-07-09 pharmacology and toxicology 10.64898/2026.07.06.736731 medRxiv
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Tenuazonic acid (TeA) is an emerging Alternaria mycotoxin frequently detected in food and feed commodities, raising concerns about its toxicological relevance. Chronic oral exposure to TeA has been reported to induce dysplastic alterations in the esophageal mucosa of mice, while human biomonitoring data indicate an association between TeA exposure and esophageal cancer, although a causal relationship has not yet been established. At a mechanistic level, the effects of TeA in esophageal cells remain poorly characterized. Therefore, this study investigated the impact of TeA on cytotoxicity, oxidative stress, DNA damage, mitochondrial homeostasis, cell-cycle distribution and transcriptomic stress responses in human esophageal KYSE-510 cells. TeA induced a concentration-dependent reduction in metabolic activity and total protein content after 24 h exposure to 0.1-100 M. Significant cytotoxicity was measured starting from 20 M. At sub-cytotoxic concentrations, TeA triggered rapid ROS formation within 5-30 min exposure and induced formamidopyrimidine-DNA glycosylase (FPG) sensitive DNA damage after 1 h exposure (5-7.5 M), indicating oxidative DNA lesions. In addition, TeA altered mitochondrial morphology after 4 h exposure at 7.5 M, manifested by shrinkage of the mitochondrial network area and perinuclear redistribution, while mitochondrial respiration showed only a non-significant tendency towards reduced respiratory capacity. RNA sequencing after 6 h exposure to 10 M TeA revealed oxidative stress-associated transcriptional changes, impaired antioxidant and stress-adaptive responses, and p53-associated stress signaling. Furthermore, TeA induced significant G2/M phase accumulation after 24 h exposure to 1-10 M.

6
Multi-fidelity Bayesian optimization of population-robust near-infrared sensors for skeletal muscle oximetry

Bhattacharyya, K.

2026-07-09 orthopedics 10.64898/2026.07.08.26357539 medRxiv
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Designing transcutaneous skeletal muscle oxygenation (SmO2) sensors requires jointly optimizing source--detector geometry and wavelength selection while guaranteeing performance across populations that vary in subcutaneous fat thickness and skin pigmentation. We present a multi-fidelity Bayesian optimization (MFBO) framework that couples Monte Carlo light-transport simulations at two photon-count fidelities to a distributionally robust design objective. An autoregressive Gaussian-process surrogate learns the correlation between inexpensive low-photon-count and accurate high-photon-count simulations, and a cost-aware acquisition function decides both where and at what fidelity to sample. Robustness across the population is enforced with Conditional Value-at-Risk (CVaR) and entropic-risk (ERM) objectives that target worst-case subjects rather than the population average. On a five-layer forearm tissue model with anthropometric variability we find (i) a fidelity regime that is favorable for MFBO where the low-fidelity surrogate is rank-informative (Spearman {rho} = 0.84) but biased, at 100x lower cost; (ii) MFBO attains 23% higher robust sensitivity than a strong high-fidelity single-fidelity baseline at equal budget (p = 0.035), and avoids the optimistic bias that causes low-fidelity-only optimization to collapse when its designs are validated at high fidelity; (iii) CVaR/ERM objectives improve worst-case tail performance by {approx}23% relative to a mean objective without sacrificing average sensitivity; and (iv) discovered designs improve robust tail sensitivity by roughly 3--6x over commercial and heuristic optode layouts, with the largest gains in the high-fat and high-melanin subpopulations. The methodology bridges stochastic light-transport physics with sample-efficient machine-learning optimization and generalizes to cerebral oximetry, photodynamic therapy planning, and wearable physiological monitors.

7
Performance of automated anterior segment OCT-based quantitative imaging in adult anterior chamber inflammation

Solebo, A.; Chen, B.; Aznan, N.; Xochiale, M.; Roberts, T.; Petrushkin, H.; Lim, C.; Shu, R.; Jacobson, M.; Farisogullari, I.; Abdelfattah, K.; Tynan, D.; Lotay, J.; Vijjan, K.; Tsika, C.; Williams, O.; Clare, G.; Testi, I.; Tucker, W. R.; Addison, P.; Pavesio, C.; Rahi, J. S.; Taylor, P.; Chu, C. J.

2026-07-10 ophthalmology 10.64898/2026.07.06.26357402 medRxiv
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Objective: To investigate the performance of anterior segment (AS) OCT quantitative imaging of anterior chamber inflammation in uveitis patients with diverse demographics. Design: Prospective cross-sectional study. Participants: 144 adult patients managed at a tertiary care service in the UK Methods: Repeated swept-source ASOCT imaging was performed pre- and post-pupil dilation (i.e. 4 scan sets). Inflammation was quantified using a validated human in the loop automated image analysis pipeline, Minuscule Cell Detection (MCD), which identified and counted putative inflammatory cells on AS-OCT. Main Outcome Measures: Test-retest variability of ASOCT and diagnostic accuracy of various ASOCT derived measurands (minimum, maximum, median counts per cross sectional image, and total counts across volume image sets per eye or MINCC, MAXCC, MEDCC and TOTCC) versus Standardization of Uveitis Nomenclature (SUN) grading system as assessed by a uveitis specialist. Results: A total of 281 eyes were included in the analysis. Median age was 48 years (IQR 36 to 64). Strong test-retest measurand reliability was demonstrated, with a 95% tolerance interval ratio 0.3 to 3.0. The best diagnostic performances for SUN activity were observed with the MINCC threshold of 3 particles (negative predictive value for clinical activity of 89.8%, 95% CI 83.0 to 94.1). Associations between ASOCT measurands and patient age (adjusted coefficient 7.5 additional particles, 95% CI 0.5 to 14.6, p<0.04 for age over 60 years versus under 44), and pigment load (52.8, 11.8 to 92.9, p<0.01 in eyes with AC pigment versus without) were noted. Conclusions: ASOCT assessment of anterior chamber inflammation in uveitis meets current recommendations for quantitative imaging biomarkers, demonstrating strong repeatability, linearity with clinical assessment scores and stability with pupil dilation and patient characteristics of ethnicity and lens status. The absence of variability in diagnostic indices across derived measurands suggests similar performance across different acquisition protocols. Further longitudinal cross-platform studies are needed to determine limitations of use.

8
Dosimetric Characterization and Workflow Optimization of the FLASH-SARRP for Reliable Preclinical Radiobiological Studies

Knol, M.; Goncalves Jorge, P.; Kunz, L. V.; Korysko, P.; Petit, B.; Durham, A.; Marie-catherine, V.; Tsoutsou, P.; Koutsouvelis, N.; Lascaud, J.

2026-07-07 cancer biology 10.64898/2026.07.06.736680 medRxiv
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Objective: Preclinical small-animal irradiators such as the FLASH-SARRP can support the advancement of photon-FLASH toward the clinic. This study aimed at characterizing the FLASH-SARRP and established a robust quality assurance (QA) workflow to enable accurate and reproducible preclinical experiments. Approach: Custom 3D-printed spacers were designed to ensure reproducible X-ray tube alignment, sample positioning and mounting of the dosimetric tools. Beam characteristics were evaluated using a combined dosimetric approach. High spatially resolved dose distributions were obtained from Gafchromic films, whereas a plastic scintillating fiber was employed to monitor in real-time the temporal pulse structure and synchronization between the two X-ray tubes. Day-to-day variability of the delivery was evaluated over several sessions. Main results: The FLASH-SARRP achieved dose-rates of around 80 Gy/s when both tubes were used simultaneously and provided a homogeneous irradiation field suitable for small-animal studies. A desynchronization between the two tubes was observed with an average delay of 10 ms, resulting in temporal dose-rate heterogeneity. Additionally, a substantial inter-session variability (~11%) was found, whereas the intra-session variability was relatively low (~4%). Inter-session variability was reduced to 5%, approaching the intra-session variability, by adding Gafchromic films/scintillator-based quality assurance (QA) workflow into the irradiation routine. Significance: This work highlights the importance of temporal dosimetry for preclinical FLASH studies. Additionally, a practical QA framework is proposed integrating real-time monitoring with reference dosimetry. The proposed work enables adaptive dose delivery, thereby enhancing the reproducibility of the irradiations, which is crucial for reliable preclinical studies on the FLASH effect.

9
Ocimum gratissimum essential oil nanoemulsions as a safe topical nanoplatform for antibacterial and wound-healing activities

Fomesseng Negoue, A.; Eya'ane Meva, F.; Fokou, J. B. H.; Voundi Olugu, S. H.; Boudjeka, V.; Ngo Nyobe, J. C.; Belle Ebanda Kedi, P.; Houatchaing Kouemegne, A. M.; Etame Loe, G.

2026-07-07 pharmacology and toxicology 10.64898/2026.07.01.735794 medRxiv
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Background: Natural essential oils exhibit antimicrobial and wound-healing properties, but their therapeutic application is limited by poor water solubility, volatility, and instability. This study developed and characterized a nanoemulsion of Ocimum gratissimum essential oil (OGNe) and evaluated its physicochemical properties, dermal safety, antibacterial activity, and wound-healing potential. Methods: Essential oil was obtained by hydrodistillation and formulated into nanoemulsions by high-speed stirring emulsification. Physicochemical properties, including pH, droplet size, polydispersity index, and storage stability, were determined. Acute dermal toxicity was assessed in Wistar rats following OECD Test Guideline 402. Antibacterial activity was evaluated using broth microdilution, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill assays. Wound-healing efficacy was investigated using an excision wound model over 21 days using distilled water and trolamine serving as controls. Results: OGNe exhibited a stable milky appearance, near-neutral pH, and droplet sizes ranging from 26 to 224 nm. No signs of dermal toxicity or behavioral abnormalities were observed after topical administration. The nanoemulsion showed selective antibacterial activity, with the highest susceptibility against Acinetobacter baumannii (MIC = 1.125 L/mL), whereas Escherichia coli remained resistant. Time-kill assays demonstrated concentration-dependent bacteriostatic activity. In vivo, OGNe significantly accelerated wound contraction from day 3 onward (p < 0.0001), achieving healing rates comparable to or exceeding those of trolamine during the inflammatory and proliferative phases. Conclusion: Ocimum gratissimum nanoemulsions represent stable, biocompatible topical formulations that combine selective antibacterial activity with enhanced wound healing, supporting their potential as phytopharmaceutical nanoformulations for the management of acute skin wounds.

10
Correlation of OCT-Based Radiomic Signatures With Dose-Associated Radiation Response in Tumor Spheroids

Arndt, M. D.; Hansler, R.; Tirinato, L.; Tkachenko, A.; Seco, J.; Schepers, U.; Spadea, M. F.

2026-07-09 cancer biology 10.64898/2026.07.08.737210 medRxiv
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Background: Three-dimensional tumor spheroids are an established radiobiology model, but scalable, reproducible readouts of dose-dependent radiation response are lacking. We evaluated whether optical coherence tomography (OCT) radiomics can quantify dose-associated response in spheroids, and how it compares with conventional brightfield morphology. Methods: This in vitro, cross-sectional study used SAS oral squamous cell carcinoma spheroids seeded at two densities (5000 and 10000 cells), irradiated at 0 to 12 Gy, and imaged on days 1 to 11 post-irradiation. Each OCT acquisition yielded co-registered structural-intensity and speckle-variance volumes. Radiomic features (shape, first-order, texture) were extracted with Radiomics.jl, filtered for repeatability, correlation-pruned, and ensemble-ranked. Dose correlation was assessed by repeated 5-fold cross-validation across five regressors, comparing brightfield-only (BF), OCT-only, and combined OCT+BF feature sets with paired Wilcoxon tests. Results: OCT-only models consistently outperformed the BF baseline (median R2 0.77 to 0.85 versus 0.61 to 0.69; p<0.001 for all regressors). Adding brightfield to OCT gave no consistent benefit, reaching significance only for Random Forest (p=0.026, power 0.62). A compact shared feature subset combined brightfield area dynamics with OCT texture, shape, and speckle-variance descriptors, all showing low repeat-scan variability relative to cohort variability. Conclusions: OCT radiomics provides a sensitive, reproducible, label-free high-throughput readout of spheroid radiation dose response that outperforms the current brightfield-based approach, without requiring concurrent brightfield acquisition.

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Optimization of process parameters for melanin nanoparticles synthesised from Pseudomonas stutzeri (BTCZ 109) using OFAT method and its anticancer property evaluation

Mathew, D.; Bhat, S. G.

2026-07-07 microbiology 10.64898/2026.07.07.736906 medRxiv
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Melanins are biological macromolecule with immense functionality synthesised by a wide spectrum of living organism. It is mainly synthesised by the oxidative polymerization of indolic and phenolic compounds through several enzymatic process. It has wide spread application in agriculture, cosmetic and therapeutic industry due to its various properties including antioxidation ability, UV protection efficiency and anticancer activity. Because of this wide range of application in different sectors, large scale production and commercialization attains enormous consideration. The present study deals with the effect of 12 different process parameters on melanin production viz., production media, incubation time, inoculum concentration, pH, temperature, agitation, carbon source, phosphate and magnesium source, CuSO4.5H2O, sodium chloride and L-tyrosine on melanin production by Pseudomonas stutzeri strain BTCZ 109 obtained from Arabian sea sediments was evaluated. After optimizing the important process parameters, the bacteria showed about ~4.65 fold increase in melanin production compared to unoptimized cultural conditions. The melanin optimized through this method was found to be nano sized. The Nano sized DOPA melanin in treating Skin cancer cell line SK ML28 which showed a dose-dependent activity with an IC50 value of 164 g/mL. All these results highlight the therapeutic efficiency of DOPA melanin Nano particle as promising bioactive molecule.

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Response surface methodology for melanin nanoparticle production optimization from producer strain Pseudomonas stutzeri BTCZ305 with invitro anti-inflammatory and wound healing potential

Mathew, D.; Bhatt, S. G.

2026-07-08 microbiology 10.64898/2026.07.08.737209 medRxiv
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Culture conditions were optimized for the production of melanin nanoparticle by the bacterial strain Pseudomonas stutzeri BTCZ 305. Response surface methodology was employed for determining the most significant fermentation conditions using variables including, pH, temperature and L-tyrosine concentration identified through one-factor-at-a time approach. Box-behnken design consisting of 17 different combinations of all these factors were performed. Using this methodology, a quadratic regression model was built and the optimal combinations of media constituents for maximum melanin production 1192.27 microg/mL were determined as temperature (32.5 degreeC), pH (8.5) and L-tyrosine concentration (7 g/L). Melanin production was obtained experimentally coincident with the predicted value and the model was proven to be adequate. The nanostructural distribution, its stability in colloidal suspension and particle size were also characterized with the help of TEM, particle size analysis and Zeta potential. The potent applicability of this molecule in anti-inflammation and wound healing was also elucidated.

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Modulation of NF-κB signaling by Alternaria mycotoxins: in vitro and in silico insights into molecular mechanisms of immunosuppression in THP-1 monocytes

Partsch, V.; Crudo, F.; Schröeder, C.; Del Favero, G.; Marko, D.

2026-07-09 pharmacology and toxicology 10.64898/2026.07.06.736814 medRxiv
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Alternaria fungi produce various structurally diverse mycotoxins, several of which exhibit immunomodulatory properties. Among these, alternariol monomethyl ether (AME), alternariol (AOH), alterperylenol (ALTP), altertoxin I (ATX-I), and altersetin (AST) have been reported to suppress lipopolysaccharide (LPS)-induced inflammatory responses. However, the precise molecular mechanisms underlying these effects remain unclear. The present study aimed to elucidate how these selected Alternaria mycotoxins (0.1-50 M) target the NF-{kappa}B signaling pathway in THP-1 monocytes. Key components of the NF-{kappa}B cascade were analyzed by immunofluorescence microscopy, Western blotting and qRT-PCR. Nuclear translocation of NF-{kappa}B p65 and its phosphorylated form (p- NF-{kappa}B p65) was assessed by Western blot, while cytokine responses were determined at transcript (qRT-PCR) and protein (ELISA) levels. Moreover, in silico docking analyses were performed to investigate potential interactions of the toxins with IKK{beta}, and receptor-mediated crosstalk was studied using the glucocorticoid receptor (GR) antagonist RU486. Co-treatment with RU486 attenuated the immunosuppressive effects of 1 and 5 M AOH, indicating partial involvement of GR-dependent mechanisms. AME, AOH, ALTP, ATX-I, and AST increased total I{kappa}B levels while reducing its phosphorylated form. Additionally, AST and ALTP decreased the protein levels of Toll-like receptor 4 (TLR4), the I{kappa}B kinase (IKK) complex, NF-{kappa}B p65, and p- NF-{kappa}B p65. While AOH (5 M) and AST (25 M) reduced nuclear translocation of p65 and p-p65, ALTP (2 M) enhanced nuclear localization despite decreasing cytokine expression. Together, these findings suggest toxin-specific interference at multiple regulatory levels of NF-{kappa}B signaling and provide novel mechanistic insight into the immunomodulatory effects of Alternaria mycotoxins.

14
Molecular Structure, DNA Binding, and Photophysical Properties of SYTOX Orange and SYTOX Green

Storm, K. R.; Pritzl, S. D.; Lin, Y.-Y.; Wiebeler, C.; Ulugol, A.; Lehmann, M.; van den Heuvel, D. J.; Blab, G. A.; Gemmecker, G.; Lipfert, J.

2026-07-08 biophysics 10.64898/2026.07.08.737150 medRxiv
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Fluorescent dyes are critical to visualizing nucleic acids in many applications. SYTOX Orange and SYTOX Green are cyanine dyes, used in dead cell staining and increasingly in single-molecule assays to probe DNA supercoiling and processing. However, their structures and effects on DNA mechanics are not or only partially known. We determine the structure of SYTOX Orange to be (E)-2-((2-(4 ((diethyl(methyl)ammonio)methyl)phenyl)-6-methoxy-1-methylquinolin-4(1H)-ylidene)methyl)-4-methyloxazolo[4,5-b]pyridin-4-ium, identical to SYBR Gold except for an aza-benzoxazol core that is fundamentally different from other dyes in the SYTOX and SYBR families. We report SYTOX Green to be (Z)-2-(bis(3-(trimethylammonio)propyl)amino)-4-((3-methylbenzo[d]thiazol-2(3H)-ylidene)methyl)-1-phenylquinolin-1-ium, similar to PicoGreen. Using magnetic tweezers, we characterize the effect of SYTOX Orange and SYTOX Green on DNA mechanics. They lengthen and unwind DNA consistent with intercalation and the DNA unwinding angles per dye are 21.1(1) degree and 20.5(1) degree for SYTOX Orange and Green, respectively. Both dyes leave the DNA bending persistence length and plectoneme size almost unaltered (<10% change up to 1 uM), which is advantageous in assays probing DNA supercoiling. Their photophysical properties reveal close agreement between single-molecule manipulation and optical absorbance and fluorescence spectroscopy. Our comprehensive set of complementary measurements relates mechanical and optical properties to the molecular structures and provides recommendations for their use in applications.

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Oral levosulpiride adjuvant to intravitreal ranibizumab for diabetic macular oedema: A 24-week randomized placebo-controlled trial

Adan-Castro, E.; Nunez-Amaro, C. D.; Villareal, J.; H. Islas, I.; Hernandez-Quijano, A.; Rodriguez-Chagoya,, B. E.; Garcia-Roa, M.; Lopez-Star, E.; Garcia-Franco,, R.; Robles-Osorio,, M. L.; Martinez de la Escalera, G.; Clapp, C.

2026-07-07 ophthalmology 10.64898/2026.07.04.26357144 medRxiv
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Background/Objective: Diabetic macular oedema (DMO) is a leading cause for visual impairment primarily managed with intravitreal anti-VEGF agents such as ranibizumab (RBZ). Levosulpiride (LSP), a prokinetic medication, was recently repositioned as a safe oral treatment for naive DMO. Here, we investigated the adjuvant effect of oral LSP in combination with intravitreal RBZ injections for treating persistent DMO. Subjects/Methods: Double-blinded, dual-centre, phase 2 trial in patients with centre-involving DMO randomly assigned to be orally treated with placebo (15 patients, 18 eyes) or LSP (18 patients, 19 eyes) along with 3 successive (4 weeks apart) RBZ intravitreal injections and a 24-week follow-up. Results: Baseline best-corrected visual acuity (BCVA) improved (p[&le;]0.04) at week 12 in both RBZ+placebo and RBZ+LSP, but improvement was maintained (p=0.009) at week 24 only in RBZ+LSP. In agreement, longitudinal changes from baseline in BCVA from weeks 12 to 24 defined superior (p=0.02) visual gains measured by the Area Under the Curve (AUC) in RBZ+LSP vs. RBZ+placebo. The baseline value of mean central foveal thickness (CFT) decreased (p[&le;]0.002) in both groups at week 12 and CFT reduction was significant (p=0.006) at week 24 only in RBZ+LSP. Also, longitudinal changes from baseline in CFT resulted in a higher AUC reduction (p[&le;]0.04) at weeks 4 to12 in RBZ+LSP vs. RBZ+placebo. No significant adverse side effects were detected. Conclusions: Adjunctive LSP showed functional and anatomical benefits over the first-line therapy with RBZ. Adjuvant properties may involve the LSP-induced intraocular upregulation and downregulation of vasoinhibin and VEGF, respectively. Larger clinical trials are warranted.

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Targeting Autophagy Accelerates Intestinal Repair after Acute Ionizing Radiation

Chaurasia, M.; Singh, A.; Natarajan, K.; Sharma, K.

2026-07-10 molecular biology 10.64898/2026.07.06.736694 medRxiv
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Radiation exposure induces systemic and cellular damage, contributing to acute radiation syndrome and long-term effects such as premature aging and carcinogenesis. At the cellular level, radiation triggers apoptosis, mutation, and transformation through oxidative damage and activation of pathways including ER stress-mediated autophagy. Autophagy plays a context-dependent dual role in stressed cells, but its contribution to intestinal recovery after acute radiation remains unclear. Here, we evaluated combinatorial radiomodification using gamma radiation (8 Gy) and autophagy modulators in whole-body irradiated C57BL/6 mice (8-10 weeks old, n = 10). Mice were treated with autophagy inducers or inhibitors and euthanized at 3-, 8-, and 30-day post-irradiation. The jejunal-ileal region was analyzed via antioxidant assays, immunoblotting, H&E staining, and immunohistochemistry. Radiation significantly altered oxidative stress and autophagy markers, including increased LC3-II and decreased SQSTM1/p62. Autophagy induction enhanced intestinal proliferation (as measured by Ki-67), whereas inhibition impaired regeneration. Rapamycin pretreatment improved survival and reduced markers of intestinal injury following 8 Gy total body irradiation (TBI), whereas chloroquine exacerbated several injury-associated parameters. Overall, our findings suggest that targeted modulation of autophagy is a promising strategy for alleviating radiation-induced gastrointestinal injury and provide mechanistic insights relevant to therapeutic development.

17
Pediatric nicotine exposures from devices and liquids: a comparative analysis of U.S. poison center data

Miller, R. S.; Varney, S. M.

2026-07-07 toxicology 10.64898/2026.07.04.26357293 medRxiv
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Introduction: Pediatric nicotine exposures remain an important and preventable public health issue, particularly with the rapid expansion of electronic nicotine delivery systems. This study compared demographic characteristics, exposure circumstances, and clinical outcomes between pediatric cases involving nicotine devices and bottled liquids reported to U.S. poison centers. Method: This retrospective cohort study analyzed National Poison Data System cases from 2011-2022 involving children aged less than 6 years exposed to nicotine devices or bottled liquids. Analyses were limited to cases with definitive medical outcomes. The primary outcome was defined as a moderate or major clinical effect or death. Odds ratios with 95% confidence intervals were calculated, with a secondary analysis restricted to route-concordant exposures. Results: The final cohort included 15,497 cases: 10,168 device exposures and 5,329 liquid exposures. Demographic characteristics were similar between groups. Device exposures more frequently involved inhalation, while ingestion predominated overall. Clinical effects were typically mild and transient, with vomiting and coughing most commonly reported. The primary outcome occurred in 1.9% of device cases and 2.0% of liquid cases (OR = 1.05; 95% CI 0.82-1.34). A secondary analysis restricted to inhalation-only device exposures and ingestion-only liquid exposures similarly found no significant difference in clinically important outcomes (OR = 1.38; 95% CI 0.92-2.12). Two deaths occurred, one in each group. Conclusion: These findings suggest that, despite differences in formulation and route of exposure, nicotine devices and bottled liquids produce broadly similar clinical toxicity profiles in young children. Prevention strategies should address all household nicotine products rather than focusing on specific delivery systems.

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Sunrise and sunset times are the main factors that determine the flowering time of photoperiod-sensitive sorghum

Clerget, B.; Sidibe, M.; vom Brocke, K.; Raharinivo, V.; Ortiz, D.; Trouche, G.

2026-07-08 plant biology 10.64898/2026.06.12.731875 medRxiv
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Crop photoperiodism models assume that flowering time is primarily controlled by daylength, yet many field observations contradict this view. We previously proposed an alternative framework integrating daily changes in sunrise and sunset times (dSR and dSS). Variety trials in Madagascar and in Argentina supported this concept: mid-late sorghum varieties from the northern hemisphere flowered late or very late when sown in November and December, consistent with the higher dSR/dSS values of the southern hemisphere summer. One Malian variety, sown monthly over six years in West Africa, exhibited high interannual variability in flowering time when sown between November and February. This revealed that up to four photoperiodic responses -- two quantitative and two qualitative, occurring at different times of the year -- may coexist within a single late photoperiod sensitive variety. All responses use only dSR and dSS cues. The qualitative responses are triggered by an internal phasic coincidence, which is set by a linear relationship between dSR and dSS at the onset of plant photoperiod sensitivity, and between dSR+dSS at panicle initiation. The research model fitted data from 28 varieties grown in Mali well. It also accurately fitted the duration to PI observed in three varieties sown at tropical and temperate latitudes. HighlightThe seasonal photoperiodic adaptation of flowering time in sorghum plants may rely on several signal transduction pathways regulated by sunrise and sunset times rather than day length.

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PREVALENCE OF FUSARIUM WILT (Fusarium oxysporum f. sp. Lycopersici) on TOMATO (Solanum lycopersicum L.) IN CHIKUN LGA, KADUNA STATE

Rilwan, O.; Ibrahim, A.

2026-07-09 plant biology 10.64898/2026.06.24.734226 medRxiv
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Tomato (Solanum lycopersicum L.) is one of the most important vegetable crops in Nigeria, serving as a major source of income, nutrition, and raw material for food industries. However, its production is severely constrained by Fusarium wilt, a destructive soil-borne disease caused by Fusarium oxysporum f. sp. lycopersici. This study investigated the prevalence and severity of Fusarium wilt on tomato in Chikun Local Government Area (LGA) of Kaduna State, Nigeria. Field survey and laboratory analyses were conducted on forty-five tomato samples from three tomato farms Kujama, Kakau, and Rido. The samples were examined for disease incidence and severity. Data were analyzed using descriptive statistics and Chi-square tests. The overall disease incidence was with Rido recording the highest infection rate (80.0%), followed by Kujama (60.0%) and Kakau (40.0%). Among plant parts, the stem exhibited the highest infection frequency (80.0%), while leaves and fruits had 60.0% and 40.0% incidence respectively. Chi-square analysis indicated no significant difference (p > 0.05) in disease incidence among farms and plant parts, suggesting uniform pathogen distribution. The research recommends the adoption of integrated disease management strategies and improved farmer awareness to mitigate the impact of the disease and ensure sustainable tomato production.

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Model-optimized stimulus distortions for adaptive estimation of individual sensory representations

Casco-Rodriguez, J.; Hong, F.; Brainard, D. H.; Feather, J.; Lipshutz, D.

2026-07-08 neuroscience 10.64898/2026.07.02.736141 medRxiv
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Representations of the same physical stimulus vary between individuals. Characterizing individual differences has practical implications, but is challenging because these representations are not directly observable. Given a model of how representations vary within a population, we propose a Bayesian adaptive procedure for estimating an individual observer's representation from a series of targeted perceptual discrimination judgments. A key component of our approach is using Fisher information to identify stimulus distortions that efficiently differentiate observers in the population. As a proof of concept, we focus on individual differences in color perception and simulate observers with cone fundamentals drawn from an individual colorimetric observer model. We demonstrate that our approach can recover key aspects of a sampled observer's cone fundamentals using simulated three-alternative forced-choice oddity judgments with approximately 500 trials, corresponding to an experimental duration of approximately one hour. Our Bayesian adaptive framework provides a promising and generalizable approach to efficiently link behavioral measurements to individual differences in sensory representations.