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This study aimed to develop and validate a hybrid deep learning-radiomics model that leveraged Cycle-consistent generative adversarial networks (CycleGAN)-synthesized contrast-enhanced computed tomography (CE-CT) images to differentiate advanced from non-advanced hepatic fibrosis. This retrospective study included 410 patients with biopsy-confirmed hepatic fibrosis (2017-2024). A trained CycleGAN model was used to generate synthetic three-phase CE-CT images from the corresponding non-contrast computed tomography (NC-CT) data. Each group of images was randomly split 6:4 ratio into training and test sets. After region of interest (ROI) segmentation, handcrafted radiomic (HCR) features were extracted. Concurrently, eight end-to-end deep learning (DL) models were trained; DL features were extracted from the best-performing model. Feature selection was performed using Spearman's rank correlation and the least absolute shrinkage and selection operator (LASSO). Six machine learning classifiers were developed for each feature type (HCR, DL, and late-fused DL features) using the final selected feature set. The performance of models was assessed by the area under the receiver operating characteristic curve (AUC), accuracy, calibration curves, decision curve analysis (DCA) and the DeLong test. Models utilizing synthetic CE-CT images outperformed those based on NC-CT. DL feature-based models surpassed HCR-based models. A late-fusion hybrid model integrating DL features further improved performance, achieving an AUC of 0.880 (95% CI: 0.819-0.942). The model based on synthetic CE-CT images demonstrated excellent diagnostic performance. Moreover, the hybrid model combining both real NC-CT and synthetic CE-CT images further improved diagnostic performance. The hybrid model can serve as a non-invasive diagnostic method for differentiating advanced from non-advanced hepatic fibrosis.

Desmin-related cardiomyopathy is a rare disorder caused by pathogenic variants in desmin and associated protein genes. We aimed to describe the clinical, histopathological, immunohistochemical, ultrastructural, and molecular features in a pediatric cohort. This retrospective descriptive study reviewed pediatric cases diagnosed over a 30-year period. Clinical data were extracted from electronic medical records. Archived histologic slides (H&E, desmin immunostains, and special stains) and electron photomicrographs were re-evaluated. Key features were documented and summarized. Four pediatric patients (3 males and 1 female) presented between ages 2 and 14 years with restrictive cardiomyopathy and conduction abnormalities. Endomyocardial biopsies and/or explanted heart specimens showed eosinophilic cytoplasmic inclusions that were desmin-immunoreactive, PAS-negative, and highlighted by toluidine blue. Electron microscopy revealed dense cytoplasmic granulofilamentous aggregates that were frequently continuous with the sarcoplasmic membrane, Z-bands, and intercalated discs. Two patients harbored the same pathogenic variant: DES c.1360T>C (p.Arg454Trp). Desmin-related cardiomyopathy should be considered in any child presenting with restrictive cardiomyopathy and/or rhythm disturbances. Distinctive light microscopic and ultrastructural features can aid in confirming the diagnosis. Certain pathogenic variants are increasingly linked to more severe phenotypes, highlighting the importance of genetic evaluation and its implications for family counseling.

This study investigates possible differences of female and male patients' data in regard to the prediction of mortality and troponin level of acute pulmonary embolism (APE) patients. Radiomics features are utilized to gain insights of sex-specific image properties, which should support APE diagnosis and treatment. A database of 200 manually segmented APE patients' computed tomographic data (100 female and 100 male) was used for the prediction of 30-day mortality and biomarker troponin level. The radiomics features were extracted from the segmented thrombi and reduced via correlation analysis and 12 feature selection followed each by 12 classification methods. For comparison, the weighted F1-Score, Matthew's Correlation Coefficient, and balanced accuracy were used. For assessment of generalizability, the study was extended to 427 automatically selected datasets. Sex-dependent differences have been found in the resulting metrics and highest achieving feature selection and classification methods. Not stratifying the dataset by sex resulted in lower performance compared to the sex-stratified male and female only calculations. The subgroup of female patients achieved up to 31.04 % higher metric values compared to the other cohorts. Different thrombus properties contributed to the prediction based on the patients' sex as well. In this study, we analyzed possible correlations between sex of APE patients and mortality and troponin levels as well as radiomics features. Our analysis identified an influence of sex on the prediction task and image feature selection. Female patient data especially had higher predictive potential, which could help for further sex-stratified analysis of APE.

Multi-emissive carbon quantum dots (CQDs) are attracting widespread attention across fields. Three kinds of nitrogen and phosphorus co-doped CQDs (NPCQDs) were synthesized through a two-step method. Firstly, phosphorus-doped CQDs (PCQDs) with blue fluorescence were rapidly prepared using maleic acid and disodium hydrogen phosphate as the carbon and phosphorus sources by microwave method. Subsequently, through the hydrothermal method, NPCQDs were successfully obtained using 3-aminophenylboronic acid, diethylenetriamine, and o-phenylenediamine as dopants and reacting with PCQDs. Their emission peaks are located at 437 nm exhibiting blue fluoresce (B-NPCQDs), 550 nm (yellow, Y-NPCQDs), and 600 nm (red, R-NPCQDs), respectively. Compared with PCQDs (11.7%), the QYs are high values of 17.32%, 41.37%, and 37.32% for B-NPCQDs, Y-NPCQDs, and R-NPCQDs, respectively. Y-NPCQDs exhibited superior fluorescence stability against most interferents, while B-NPCQDs and R-NPCQDs served as selective fluorescent probes for Fe2+ and Ag+/Cu2+ detection, respectively. For fingerprint imaging, Y-NPCQDs@Al2O3 composites achieved clear visualization of fingerprint first-, second-, and third-level features. In comparison, B-NPCQDs@Al2O3 only revealed first-level features with insufficient detail, while R-NPCQDs@Al2O3 led to blurred images due to excessive adhesion to the substrate. In fruit preservation, 0.5% Y-NPCQDs/PVA film showed the optimal effect on jujubes, maintaining good fruit color and plumpness for 13 d and significantly delaying ripening.

Rare genetic disorders affecting enamel pose considerable challenges for clinicians due to their scarcity, limited documentation, and variable clinical manifestations, making accurate diagnosis and effective management particularly complex. These conditions may also affect tooth number, shape, and eruption, further complicating dental rehabilitation. The authors focused this review on selected syndromic disorders characterized by distinctive phenotypic features affecting teeth and other systems, with enamel defects likely to be first encountered by dental care providers. The authors' objective was to synthesize the knowledge on genetic etiologies, functional consequences, oral manifestations, and dental management strategies, complemented by means of clinical and radiographic illustrations. The authors used searches of the PubMed and Online Mendelian Inheritance in Man databases as well as critical analysis of original research, topical reviews, and case reports. More than 115 genes and conditions were identified, and 8 conditions were selected for their genetic and clinical relevance. The authors integrated case descriptions and images to help readers understand these disorders and visualize their key features, including genetic etiology and clinical management. Due to the rare nature of these conditions, the authors relied on published reports featuring clinical photographs and radiographs. Rapid advances in the genetic understanding of rare disorders affecting teeth underscore the need for dental care providers to become familiar with these conditions. Investigating their genetic basis clarifies the origins of dental anomalies and highlights the involvement of other organ systems, reinforcing the importance of recognizing these disorders as relevant beyond oral health.

DFT calculations were conducted to investigate the Au(I)-catalyzed one-pot reaction of propargylsilane (R1) and aldehyde (R2), which exclusively provides the trans-2-silyl-4,5-dihydrofuran (tP) without the formation of the corresponding cis-isomer (cP). Key findings reveal that the unconventional chemoselectivity─wherein the nucleophilic attack of R2 occurs at Si(-Me3) rather than the alkyne C atom─originates from the stronger electrostatic interaction between the carbonyl O atom of R2 and the Si(-Me3) cation. Subsequently, following re/si-face addition, an "O(TMS) nucleophilic cyclization-promoted" catalytic mechanism was established to account for the formation of cP/tP, characterized by two key features: (i) the O(TMS) nucleophilic cyclization weakens its σ-interaction with the Si(-Me3) atom, thereby facilitating subsequent Si(-Me3)-migration─distinct from the challenging cleavage of the inherently inert O-Si σ-bond; (ii) the resultant outer-sphere protodeauration ensures significant σ-type orbital overlap between the migrating H and Au-attached C atom, circumventing the energetically unfavorable orbital angular misalignment characteristic of the classical inner-sphere pathway. Furthermore, the in situ-generated cP coordinates with the active [Au]+ catalyst, forming an oxonium cation intermediate. This intermediate features the activation of the rigid (aryl)C-O σ-bond on the dihydrofuran ring, which contributes significantly to the cis-trans isomerization (cP → tP). Consequently, the exclusive diastereoselectivity is achieved. These insights are anticipated to facilitate the rational design and optimization of innovative synergistic catalytic systems.

Primary cutaneous cryptococcosis (PCC) is a rare, localized fungal infection caused by Cryptococcus species, typically following direct inoculation of the yeast into the skin in immunocompetent individuals. Unlike disseminated cryptococcosis, which is more common in immunocompromised hosts, PCC remains confined to the skin and often arises after minor trauma or environmental exposure. Although traditionally associated with Cryptococcus neoformans (C. neoformans), Cryptococcus gattii (C. gattii) is also increasingly recognized in immunocompetent hosts. Dermatologists are crucial in the early identification of PCC, as its clinical presentation can resemble other dermatologic conditions such as bacterial cellulitis, pyoderma gangrenosum, or atypical mycobacterial infections. This review provides a comprehensive overview of the epidemiology, clinical features, diagnostic methods, and management strategies for PCC. It emphasizes the importance of differentiating PCC from disseminated cryptococcosis and other mimicking conditions. Treatment with oral azoles, such as fluconazole, is typically effective, with a favorable prognosis for most immunocompetent patients. The review also includes practical diagnostic algorithms to assist clinicians in the accurate and timely management of PCC, ultimately improving patient outcomes and reducing unnecessary interventions.

Microorganisms are increasingly recognized as biological factors that may influence asphalt materials performance and pavement service behavior. This review integrates petroleum biodegradation mechanisms, petroleum asphalt composition, and direct asphalt evidence to examine microbial effects in asphalt systems. The results show that microbial effects mainly depend on preferential fraction transformation and environmental regulation. Light and bioavailable fractions, especially saturates and some aromatic compounds, are more easily utilized, whereas resins and asphaltenes are more resistant but may still undergo limited transformation. Environmental factors regulate microbial activity, substrate availability, and mass transfer. Direct studies show microbial action may consume light fractions, enrich heavy fractions, change surface and molecular features, weaken adhesion, increase viscosity or stiffness, and reduce water stability, thereby promoting asphalt deterioration during service. Controlled microbial processes may support asphalt modification, recycling, regeneration, and sustainable maintenance. Future studies should clarify asphalt-specific microbial mechanisms and assess their sustainable potential in asphalt recycling and maintenance.

Idiopathic inflammatory myopathies (IIMs) are frequently complicated by interstitial lung disease (ILD). The independent clinical significance of myositis autoantibody positivity remains incompletely defined. We performed a retrospective cohort study of patients undergoing myositis autoantibody testing at a single tertiary center (1997-2022). Multivariable logistic regression assessed the association between antibody positivity and ILD. Subgroup analyses evaluated clinical phenotypes and radiologic patterns. Among 1,034 patients included in the analysis, 359 (34.7%) were positive for at least one myositis autoantibody and 365 (35.5%) had ILD. Antibody-positive patients were younger, more frequently female, and had a higher prevalence of ILD compared to antibody-negative patients (41.2% vs 32.2%, p&#x2009;<&#x2009;0.01).Myositis antibody positivity was independently associated with ILD (adjusted OR 1.78, 95% CI 1.33-2.37, p&#x2009;<&#x2009;0.001). Increasing age, higher BMI, former smoking status, and Asian ethnicity were also associated with ILD. Among patients with ILD, antibody-positive individuals had a higher prevalence of systemic autoimmune features, including Raynaud's phenomenon, arthritis, and mechanic's hands, as well as higher inflammatory markers and more impaired pulmonary function. Myositis autoantibody positivity is independently associated with ILD and identifies a distinct clinical phenotype. These findings should be interpreted in the context of the study's retrospective, single-center design.

The synthesis of disubstituted polypeptoids, or N-substituted polypeptides, remains challenging due to steric hindrance. Here, a synthetic platform, with orthogonal functional side chains, was developed for the construction of structurally diverse disubstituted polypeptoids. Poly(N-allyl S-methyl cysteine) was synthesized by acetic acid-catalyzed controlled ring-opening polymerization. Subsequent methylation yielded the sulfonium-pendant polymer, which underwent base-catalyzed elimination of sulfonium groups to generate well-defined poly(N-allyl dehydroalanine). This polymer features two orthogonal reactive sites, electrophilic &#x3b1;,&#x3b2;-unsaturated carbons and N-allyl groups, which could undergo selective modification through sequential orthogonal reactions. Michael addition reaction preferentially functionalized the &#x3b1;,&#x3b2;-unsaturated sites while preserving allyl groups for subsequent thiol-ene click chemistry. This strategy enabled precise installation of alternating functional side chains, yielding structurally diverse disubstituted polypeptoids with high functional group density and programmable side-chain sequences. The combination of efficient orthogonal functionalization, tunable side-chain arrangement, and dense functionality establishes these disubstituted polypeptoids as versatile scaffolds for different applications.

Purpose To develop a machine learning-based model to identify patients with hypertrophic cardiomyopathy (HCM) at high risk of major adverse cardiac events (MACEs) and key predictors of model performance. Materials and Methods This retrospective cohort study included patients who underwent cardiac MRI for HCM evaluation between September 2015 and December 2022. Cardiac MRI included balanced cine steady-state free precession, native T1 and T2 mapping, and late gadolinium enhancement. MACEs were defined as a composite of cardiovascular death, resuscitated sudden cardiac death, or heart failure hospitalization. A penalized Cox proportional hazards model with elastic net regularization (CoxNet) was developed with 33 clinical, genetic, echocardiography, and cardiac MRI variables. Model training used 200 iterations of stratified subsampling cross-validation (80% training, 20% testing). Performance was evaluated with the Harrell C index and compared with the 2014 European Society of Cardiology sudden cardiac death risk model. Results A total of 604 patients were included (mean age, 52 years &#xb1; 15 [SD]; 417 male patients; median follow-up, 3.0 years [IQR, 1.9-4.2 years]). The CoxNet model demonstrated favorable performance for MACE prediction (C index, 0.75; 95% CI: 0.65, 0.83), similar to the European Society of Cardiology model (C index, 0.67; 95% CI: 0.57, 0.75; P = .07). Key predictors included apical aneurysm, left ventricular end-systolic volume indexed to body surface area, extensive late gadolinium enhancement, native T1 z score, and male sex. Conclusion A machine learning-based model comprising routinely available variables showed strong performance for MACE prediction in HCM. Key variables highlight the impact of cardiac MRI features on risk stratification. Keywords: MRI, Machine Learning, Model Training, Cardiac, Heart, Hyperplasia, Hypertrophy &#xa9; RSNA, 2026 See also commentary by Shiwani in this issue.

As colorectal cancer survival improves, survivors face an increased risk of subsequent primary cancers (SPCs). This systematic review assessed associations between cancer treatments, tumor features and other risk factors and the risk of SPCs for colorectal cancer survivors. We searched four databases for peer reviewed articles published up to October 2025. We conducted meta analyses using random effects models to summarize pooled relative risks (RRs) for each SPC. Of 10,577 articles screened, 36 met the inclusion criteria. Radiotherapy was associated with increased risks of uterine (RR 2.65; 95% confidence interval [CI] 1.63-3.67), ovarian (RR 2.26, 95%CI 1.30-3.91), urethral (RR 4.66, 95%CI 1.96-11.06) and lung cancer (RR 1.19, 95%CI 1.04-1.35) but a decreased risk of prostate cancer (RR 0.55, 95%CI 0.47-0.64). In women, chemotherapy was associated with increased risks of uterine (RR 2.26, 95%CI 1.63-3.15) and breast cancer (RR 1.22, 95%CI 1.05-1.43). Colon (vs rectal) and proximal colon (vs distal) cancers were associated with higher SPC risk, whereas stage II/III (vs stage I) was associated with lower SPC risk. Older age, male sex, White race (vs Black/Asian), smoking, alcohol use and metabolic comorbidities were associated with increased SPC risk. These findings support the need for risk based surveillance after colorectal cancer.

Interlobular septal thickening (ILST) is a feature on chest computed tomography (CT) that is characterized by abnormal widening of the interlobular septa, which are thin connective tissues that separate secondary pulmonary lobules within the lung parenchyma. They contain pulmonary venules and lymphatic vessels. On CT, these septa are normally not visible in healthy patients. However, various pulmonary pathologic conditions can lead to ILST. If present, ILST can be categorized into 3 different patterns based on its morphologic appearance: smooth, nodular, and irregular/fibrotic. Each pattern occurs from different disease processes with little overlap. In this pictorial essay, we review common and rare etiologies for each type of ILST. For each disease, we discuss relevant pathophysiology, epidemiology, risk factors, symptoms, physical exam findings, labs, and management. Subsequently, we present the ILST features along with the distribution (eg, unilateral, bilateral, central, peripheral) and ancillary imaging findings that can support the diagnosis. Finally, characteristic and high-resolution figures are presented.

Background Cardiac sarcoidosis (CS) may present with conduction abnormalities, ventricular arrhythmias, and heart failure. The delay in recognizing cardiac involvement in systemic sarcoidosis leads to disease progression, resulting in major morbidity and mortality. We studied the clinical, electrocardiographic, and imaging features of cardiac sarcoidosis and its mortality predictors. Methods The clinical data of patients with CS who presented to the Sree Chitra Tirunal Institute for Medical Sciences and Technology between 2005 and 2021 were retrospectively analysed. The diagnosis of CS was based on the 2014 Heart Rhythm Society Expert Consensus recommendations and the 2016 Japanese Circulation Society clinical diagnosis criteria. Patients with obstructive coronary artery disease and possible myocarditis were excluded from the study. Results Forty-three patients of CS (31 males), aged 49 (8.8) years, were followed up for a mean duration of 4.3 (range 1.87-6.5) years. The presenting clinical manifestations were ventricular tachycardia (VT) 14/43 (33%), acute heart failure 14/43 (33%), complete heart block 10/43 (23%), and non-sustained VT/symptomatic ventricular premature complexes 2/43 (5%). Systemic manifestations included lymphadenopathy 28/43 (65%), pulmonary parenchymal involvement 26/43 (60%), and neurological involvement 8/43 (19%). The mean basal left ventricular ejection fraction at presentation was 41.1% (standard deviation 16.1%), and 31/33 (94%) of the patients had late gadolinium enhance-ment in cardiac MRI, with the predominant pattern being sub-epicardial 18/33 (58%) or mid-myocardial 17/33 (54%). Eighteen (42%) patients received implantable cardioverter defibrillator (ICD); nearly half had appropriate ICD shocks. On follow-up, 11 (25%) patients died, 10 (23%) had recurrent heart failure admissions, and 5 (29%) had recurrent ICD shocks. Multivariate analysis revealed higher New York Heart Association (NYHA) class/clinical heart failure at presentation, elevated erythrocyte sedimentation rate at diagnosis, and persistent low ejection fraction during follow-up to be predictors of mortality, not VT. Survival analysis showed that recurrent heart failure admissions predict early mortality. Conclusion Although arrhythmia was the most common manifestation, clinical heart failure was seen in nearly half of the patients with a diagnosis of CS. A high prevalence of heart failure, along with 25% mortality in our study, may indicate a delayed recognition of cardiac involvement in these patients' natural history. Recurrent heart failure admissions predicted early mortality.

Low-dose methotrexate (MTX) (5-25&#xa0;mg/week) is widely used in the treatment of autoimmune diseases and is considered relatively safe. There have been reports of toxicities caused by MTX, but the characteristics remain unclear. Through a retrospective case series at our hospital, we describe the clinical features, management, and outcomes of adverse reactions caused by MTX. This is a retrospective, single-center case series of patients with rheumatoid arthritis (RA) who developed adverse reactions while receiving low-dose MTX (5-25&#xa0;mg/week) between March 2022 and August 2025. Exclusion criteria included adverse reactions due to other drugs, viral infections, or vitamin B12/folate deficiency. We present only descriptive statistics (median, range, frequency). The series included 18 patients. Of these, 77.78% were female. Median age was 72&#xa0;years (51-77&#xa0;years). Median MTX dosage was 10&#xa0;mg (7.5-35&#xa0;mg) weekly. Adverse reactions involved multiple organ systems. Hematological adverse reactions were primarily characterized by cytopenia, anemia, and bleeding. Gastrointestinal adverse reactions were nausea and vomiting. Skin-related adverse reactions included skin ulcers, erythema, swelling, and pain. Leucovorin calcium rescue therapy via intravenous administration was given in 77.78% of patients. Additionally, 9 patients (50.00%) required blood transfusion, 8 patients (44.44%) received recombinant human granulocyte-stimulating factor, and 5 patients (27.78%) were treated with sodium bicarbonate for urine alkalization. During hospitalization, 2 patients (11.11%) died, both due to severe infectious complications. Most adverse reactions caused by low-dose MTX were manageable with supportive care. However, severe toxicity (including fatalities) occurred in elderly or frail patients. Serum MTX concentration showed inconsistent associations with adverse reactions and should not be relied upon to predict low-dose MTX toxicity.

Comorbid insomnia and sleep apnea (COMISA) is a highly burdensome phenotype with additive effects on symptoms, quality of life, and health outcomes. Although obstructive airway diseases (OAD)-including asthma and chronic obstructive pulmonary disease-commonly coexist with sleep complaints, the association between OAD and COMISA in large sleep-clinic cohorts remains unclear. We investigated whether OAD is independently associated with COMISA in a nationwide cohort undergoing full-night polysomnography (PSG). We analyzed 12,715 adults in the Turkish Sleep Apnea Database (TURKAPNE), a prospective, multicenter registry. Demographics, comorbidities, insomnia symptoms, and PSG parameters were compared between individuals with and without OAD, defined as self-reported, physician-diagnosed asthma or COPD. COMISA was defined as the coexistence of obstructive sleep apnea (apnea-hypopnea index&#x2009;&#x2265;&#x2009;5 events/h) and insomnia symptoms occurring "often" or "very often." Multivariable logistic regression was used to determine the independent association between OAD and COMISA. OAD was present in 12.2% of participants (n&#x2009;=&#x2009;1,546). COMISA prevalence was higher in those with OAD than in those without OAD (16.1% vs 10.8%, p&#x2009;<&#x2009;0.001). After adjustment for age, sex, body mass index, education, smoking status, and comorbidities, OAD remained independently associated with COMISA (adjusted odds ratio 1.19; 95% CI 1.06-1.35; p&#x2009;=&#x2009;0.004). Among participants with COMISA, individuals with OAD were older, more frequently female, more obese, and demonstrated shorter total sleep time, longer wake after sleep onset, higher periodic limb movement index, and poorer nocturnal oxygenation. In this nationwide sleep-clinic cohort, OAD was independently associated with COMISA. COMISA patients with OAD exhibited more adverse clinical and polysomnographic features. These findings highlight the multidimensional sleep burden in OAD and support integrated, personalized management strategies.

Aluminum nitride (AlN) is an ultrawide-bandgap semiconductor whose large intrinsic band gap limits low-energy interband optical absorption. This work compares Ce substitution at the Al site, C substitution at the N site, and Ce-C co-substitution in wurtzite AlN to clarify how Ce 4f/5d states and C 2p states modify the local structure, band-edge electronic states, and optical response. Among five neutral CeAl-CN configurations considered in a 2&#x2009;&#xd7;&#x2009;2&#x2009;&#xd7;&#x2009;2 supercell, the nearest-neighbor Ce-C pair has the lowest total energy, with the other configurations lying 6.6-17.7 meV higher. The selected Ce-C pair also has a negative binding energy of -3.26 eV relative to the corresponding isolated single-substitution reference supercells. Structural relaxation shows lattice expansion after substitution, with the largest volume increase of 7.93% obtained for AlN:Ce-C. The calculated band gap of intrinsic AlN is 4.19 eV, whereas the effective electronic gaps of AlN:C, AlN:Ce, and AlN:Ce-C are 3.59, 2.18, and 2.04 eV, respectively. Since AlN:Ce-C is only 0.14 eV smaller in effective gap than AlN:Ce, the role of Ce-C co-substitution is interpreted mainly through defect-pair energetics, orbital redistribution, and local population changes rather than as a large additional band-gap narrowing. DOS/PDOS and population analyses show that C 2p states mainly modify the occupied valence-edge region, Ce 4f/5d states contribute near the band-edge and conduction-band regions, and Ce-C co-substitution induces finite spin population on C together with a nonzero Ce-C bond population. The scissors-corrected optical spectra show increased low-frequency dielectric and refractive responses, with &#x3b5;&#x2081;(0)/n(0) changing from 3.805/1.951 for intrinsic AlN to 4.449/2.109 for AlN:Ce-C, while AlN:C gives the largest low-frequency values of 4.530/2.128. Additional low-energy interband absorption and attenuation features appear especially in AlN:C and AlN:Ce-C, associated with defect-related transitions involving C 2p and Ce-related states. These changes are interpreted as calculated interband optical-response redistribution within the present neutral-defect supercell framework, not as direct evidence of device-level optoelectronic performance. First-principles calculations were performed using the CASTEP module in Materials Studio. The exchange-correlation interaction was described using the generalized gradient approximation with the Perdew-Burke-Ernzerhof functional, and on-the-fly-generated ultrasoft pseudopotentials were employed. Intrinsic AlN, AlN:Ce, AlN:C, and AlN:Ce-C were constructed from a fully relaxed 2&#x2009;&#xd7;&#x2009;2&#x2009;&#xd7;&#x2009;2 wurtzite AlN supercell containing 32 atoms. Single-doped models were constructed by replacing one Al or one N atom, corresponding to 6.25% substitution on the relevant sublattice. The co-doped model contains one CeAl-CN pair, corresponding to xCe&#x2009;=&#x2009;yC&#x2009;=&#x2009;0.0625 in Al1-xCexN1-yCy, or a combined sublattice substitution level of 12.5%. A plane-wave cutoff energy of 700 eV and a 4&#x2009;&#xd7;&#x2009;4&#x2009;&#xd7;&#x2009;3 k-point mesh were used. Intrinsic AlN was calculated using non-spin-polarized GGA-PBE, C-doped AlN using spin-polarized GGA-PBE, and the Ce-containing systems using spin-polarized GGA-PBE&#x2009;+&#x2009;U. A Hubbard U correction of 5 eV was applied only to the Ce 4f orbitals. Band structures, TDOS/PDOS, Mulliken and Hirshfeld population analyses, representative bond populations, and optical properties were calculated. The dielectric function, complex refractive index, absorption coefficient, and reflectivity were obtained within the linear-response framework using a 2.01 eV scissors correction only for optical-property calculations.