Browse Articles

Biosynthesis of Fluorinated Aromatic Polyketides Through Directed Evolution of Fused Type III Polyketide Synthase

ABSTRACT Aromatic polyketides have gained significant attention as prominent plant‐derived polyphenol molecules in recent years owing to their multi‐faceted therapeutic potentials against a variety of diseases. However, the introduction of unique fluorine atoms into the core structure of aromatic polyketides has received limited exploration thus far. In this study, a series of new‐to‐nature fluorinated aromatic polyketides, including resveratrol, naringenin chalcone, bisnoyangonin, and benzalactone, were obtained from readily available fluoro‐tyrosines in E. coli via a multi‐enzyme cascade pathway. A series of combinational optimization strategies, including metabolic regulations, double protein fusion (4CL::III‐PKS and MatB::III‐PKS), and directed evolution of the rate‐limiting enzymes, were conducted to improve the production of fluoro‐aromatic polyketides, thus enhancing the titers to >200 mg/L from an initial ∼10 mg/L. When both sides of the phenolic hydroxyl group of 4‐coumaroyl‐CoA contain fluorine atoms, a novel catalytic pathway of STS and CHS in synthesizing methyl ketone structures is unlocked, namely the “ proximal fluorine‐induced III‐PKS catalytic truncation ”. Further post‐functionalizations by enzymatic glycosylation reaction and chemocatalytic Friedel–Crafts‐type reaction provided the corresponding fluorinated derivatives of polyphenolic natural products (piceid and arahypin).

Linking maternal and pup iron mobilization in a diving mammal using iron isotope composition

Understanding the transition to motherhood among adolescent mothers in rural Pakistan: Implications for mental health

Purpose This study explored how adolescent mothers in Pakistan experience the transition to motherhood and the mental health challenges that arise during this period. Methods A focused ethnographic study was conducted with 25 adolescent mothers in Matiari, Sindh. Data were collected through semi‑structured interviews, participant observations, and artifact elicitation. Meleis’ Transition Theory informed the study focus and development of the interview guide. Reflexive thematic analysis guided interpretation, informed by an intersectional lens. Findings Five themes described mothers’ experiences: early educational disruption and redirected aspirations; continuous caregiving with uneven support; barriers to maternal healthcare access; emotional distress and psychological strain; and identity transformation. These intersecting challenges contributed to significant mental health strain and highlighted persistent gaps in access to supportive, adolescent-responsive maternal care. Conclusions Adolescent mothers navigate motherhood with substantial emotional and practical burdens yet demonstrate meaningful resilience. Findings highlight the need for adolescent‑responsive mental health support, accessible care, routine and confidential distress screening, referral pathways, and supportive educational and community‑based interventions tailored to underserved rural settings.

[O─I─O] ⁺ Halogen‐Bonded Complexes of Pyridine <i>N</i> ‐Oxides

ABSTRACT Eight [O─I─O] + halogen‐bonded complexes derived from pyridine N ‐oxides have been characterized by single‐crystal x‐ray diffraction analysis. In these 3‐ center ‐4‐ electron (3 c 4 e ) halogen‐bonded systems, iodine(I), in its simplest halogen bond (XB) donor form, functions as a bidentate electron acceptor, symmetrically engaging two monodentate N ‐oxide O‐atoms. The I + ─O bond lengths of 2.172(17)‐2.227(6) Å represent the shortest XBs reported for N ‐oxide‐based systems. Solution complexation was studied by 1 H, 15 N HMBC NMR spectroscopy. With the crystallographic verification of the previously elusive [O─I─O] + motif, Density Functional Theory calculations were performed to compare the electronic and bonding characteristics of [N─I─N] + , [O─I─O] + , and [S─I─S] + systems. The computations reveal a distinct behaviour for the [O─I─O] + complexes. Unlike nitrogen and sulfur counterparts, the N ‐oxide O‐atom in [O─I─O] + complexes retain an active electron residual viz. second lone pair, rendering these complexes susceptible to secondary interactions such as hydrogen bonds. This distinctive bonding environment establishes [O─I─O] + complexes as a unique class within 3 c 4 e halogen‐bonded systems and highlights their potential utility in the rational design of organic reactions and supramolecular materials.

Simulation study on prescribed-time stabilization of 5-DOF exoskeletons using a regularized super-twisting approach

Abstract This paper proposes an enhanced Prescribed-Time Super-Twisting Controller (PT-STC) for 5-DOF upper-limb rehabilitation exoskeletons. A regularized scaling transformation is introduced to ensure tracking error convergence to a tunable $$\varepsilon$$ -neighborhood of the origin within a user-defined time window, independent of initial conditions and disturbance magnitudes. The terminal error bound is characterized as $$\Vert e(T_{user})\Vert \le \mathcal {O}(\varepsilon )$$ , providing a systematic trade-off between convergence precision and control effort through the selection of $$\varepsilon$$ . Unlike conventional prescribed-time approaches, the proposed “Soft-Landing” mechanism eliminates gain explosion singularities, thereby preventing actuator saturation and maintaining control signals within safe operational limits in simulation. The integration of the Super-Twisting Algorithm within the scaled coordinate domain yields chattering-free torque profiles essential for safe human-robot interaction. The theoretical developments are validated through high-fidelity simulations under nominal stabilization and dynamic tracking with impact disturbances. Results demonstrate a settling time of approximately 1.99s, with significant reductions in both settling time and total variation relative to conventional sliding mode control. These findings suggest that the PT-STC offers a promising balance between temporal precision and smooth actuation, warranting further experimental investigation. We emphasize that the current results are simulation-based; experimental validation is required before clinical deployment.

Suicidal ideation, mental health services, and barriers to care among syringe services program clients who use opioids

Introduction People who use opioids (PWUO) experience a disproportionately high burden of suicidal risk. Syringe services programs (SSPs) are a critical point of contact for this population, providing low-threshold, harm-reduction services. However, gaps persist in understanding suicidal risk among individuals attending SSPs and the extent to which such risk is associated with mental health service utilization in this setting. This study aimed to assess the prevalence and specific risk factors for suicidal ideation (SI) in PWUO, as well as their use of and barriers to accessing mental health services. Methods We conducted a cross-sectional survey between April and June 2024 among PWUO (N = 199) who were utilizing services in the SSP in New Haven, Connecticut. We used the ninth item from the Patient Health Questionnaire (PHQ-9) scale, which assesses passive thoughts of death and self-harm in the past two weeks, as a proxy measure for the SI. Additionally, participants reported their use of and barriers to accessing mental health services in the past six months. Bivariate and multivariable logistic regression were conducted to examine factors associated with SI. Results Approximately 84% of participants met the criteria for opioid dependence, and more than two-thirds (71.9%) were currently receiving medication for opioid use disorder. Over one-third of the sample reported SI in the past two weeks (34.7%). Additionally, over one-third of participants (36.2%) reported unmet mental health needs, and 84.4% reported experiencing at least one barrier to accessing mental health services. Individuals with depressive symptoms (aOR: 5.4; 95% CI: 2.5–11.7) were more likely to report SI, while those who were aware of naloxone (aOR: 0.2; 95% CI: 0.1–0.6) were less likely to report SI in the past two weeks. Conclusion Our study showed a high prevalence of SI among SSP clients who use opioids and a low use of mental health services due to access barriers. These findings support incorporating a brief suicide risk screening and referral options within SSPs and other settings serving PWUO and addressing key access issues like cost and transportation that can prevent timely linkage to mental health services.

Correction to “Multivariate Sulfate‐Pillared Metal Azolate Frameworks With Tunable Flexibility for CO ₂ Capture From C2 Hydrocarbons”

M-truncated bilinear neural network method with qualitative analysis for nonlinear partial differential equations

PM-DUnet: Fusing long-range dependencies and attention in a dual-U architecture for thyroid nodule segmentation

For medical image segmentation, accurately balancing local details and global long-range dependencies is critical to tackling thyroid nodule challenges (variable sizes, ambiguous boundaries, complex context). Traditional CNNs excel at local feature extraction but are constrained by local receptive fields, hindering efficient global dependency modeling. To address this, we propose a Parallel Mamba Dual-U Network (PM-DUNet). It adopts a cascaded dual U-Net encoder-decoder for two-stage “coarse-to-fine” segmentation refinement. We design a Multi-Path Parallel Mamba (MPM) module—using State Space Models (SSMs)—to efficiently model global context with linear complexity. Additionally, Squeeze-Excitation Downsampling (SED) and Spatial Attention Upsampling (SAU) modules are integrated to adaptively enhance key features in encoding/decoding. Results show PM-DUNet achieves highly competitive performance and outperforms state-of-the-art methods on most core metrics, verifying its effectiveness and robustness for complex medical image segmentation. Our code is available on https://github.com/Andrevict/MPDUNet .

Energy Transfer‐Mediated Magnetoluminescence of an Octahedral Mn ^II Complex Ligated With Bis(Diphenylphosphino)Methane Dioxide

ABSTRACT Magnetic‐field effect on luminescence (MagLum) has attracted considerable attention owing to fundamental understanding of spin‐luminescence correlations as well as its potential application to functional magneto‐optical devices. Recent studies have revealed that open‐shell luminescent molecular systems, including organic radicals and lanthanide complexes, exhibit MagLum. However, the underlying mechanisms in such molecular systems are largely restricted to those based on simple Zeeman splitting of spin sublevels. Here, we report pronounced MagLum behaviors of an octahedral Mn II complex ligated with bis(diphenylphosphino)methane dioxide ([ Mn II L 3 ](BF 4 ) 2 ) doped into the corresponding Zn II complex ([ Zn II L 3 ](BF 4 ) 2 ) solids at various concentrations (1, 5, 10, 30 wt%). We demonstrate that the magnetic‐field modulation of the energy‐transfer efficiency from the Zn II complex to the Mn II complex is a key process governing the MagLum behaviors. This mechanism is distinctly different from those for organic radicals and lanthanide complexes, establishing a novel strategy for realizing MagLum. Our findings extend the scope of magnetic field‐responsive luminescence materials to paramagnetic transition metal complexes, thereby opening new avenues for the design and application of paramagnetic luminescent compounds in future photo‐ and spin‐based technologies.

Qubit-efficient quantum intrusion detection using dual-parameter encoding and multi-metric calibration

Analysis of the characteristics of spino-pelvic sagittal parameters in Degenerative Thoracolumbar Kyphosis deformity and the mechanism of sagittal imbalance

Background Degenerative thoracolumbar kyphosis (DTLK) is a subtype of adult spinal deformity. If DTLK progresses further, it can develop into global kyphosis (GK). Although numerous studies have described the sagittal parameters of the spino-pelvic in adult spinal deformities, there is currently no report on the sagittal parameters of DTLK. To date, there have been no reports that elucidate the mechanism of sagittal imbalance by comparing it with sagittal balance, or by examining the sagittal parameters of healthy individuals. To address this gap, the study employed a retrospective analysis, measuring parameters such as the sagittal vertical axis (SVA), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis angle (LL), upper arc of total lumbar lordosis (UALL), lower arc of total lumbar lordosis (LALL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), spino-sacral angle (SSA), and PI-LL. This study aims to clarify the occurrence and compensatory mechanisms of sagittal balance and sagittal imbalance in patients with DTLK. Objective To investigate the spino-pelvic sagittal parameters in patients with degenerative thoracolumbar kyphosis and the compensatory mechanisms for the occurrence of sagittal imbalance. Method Our research is a cross-sectional study. The imaging data used in this study were extracted on August 15, 2025. A retrospective analysis was conducted on the preoperative imaging data of 339 patients diagnosed with DTLK at Fuyang People’s Hospital from 2016 to 2025. The sagittal parameters of the spino-pelvic were measured using Surgimap software and compared to those of healthy individuals as documented in the literature. The data were divided into a balanced group and an imbalanced group based on SVA and the spino-pelvic parameters of healthy individuals. The balanced group was then compared with the imbalanced group. Results The spino-pelvic sagittal parameters of DTLK patients were significantly different from those of healthy individuals. In the balanced group, TK, TLK, LL, and PT were higher than those of normal individuals, while SS, PI, PI-LL, SSA, and UALL were lower than those of normal individuals. Compared with the imbalanced group, the balanced group had higher TK, TLK, LL, LALL, and SSA and lower SS, PT, PI-LL, and UALL. SVA showed significant correlations with multiple sagittal parameters. Conclusions DTLK patients exhibit significant differences from healthy individuals in various sagittal parameters. Balance is primarily maintained through the posterior tilt of the pelvis and a reduction in the lumbar lordosis to compensate. When an imbalance occurs, the LL, LALL, UALL, PT, and PI-LL increase as compensatory mechanisms for the loss of balance. Once the UALL is exhausted, compensation shifts to an anterior convexity of the lower lumbar curve and a posterior rotation of the pelvis.

Strengthened Charge‐Selective Perovskite/SAM Heterocontact for Efficient and Durable Perovskite Solar Cells via Interfacial Reconfiguration

ABSTRACT Hole‐selective self‐assembled molecular (SAM) layer plays a critical role in driving the optoelectronic performance of inverted perovskite solar cells (PSCs). Nevertheless, the inherent aggregation of SAMs at the buried heterocontact that causes large energy loss and severe instability, strongly hinders PSCs’ practical deployment. Herein, we propose an effective in situ strategy of reconfiguring a robust buried hole‐selective heterocontact between SAM and perovskite to promote charge extraction with improved energetics, while suppressing the formation of interfacial voids and defects. We also demonstrate that thermally activated polymerization network densely covers the SAM at the heterocontact, minimizing underlying electrode exposure and preventing upper perovskite decomposition. Simultaneously, perovskite film directly grown on network exhibits a higher crystallinity, along with releasing the residual stress. Consequently, the PSC achieves an impressive efficiency of 26.87% for 1.57 eV bandgap cells and one of the highest fill factors of 87.04% reported so far. Encouragingly, the modified device features an excellent thermal and operational stability, significantly advancing the progress of PSCs toward industrialization.

Metabolic adaptations of starving purple sea urchins (Strongylocentrotus purpuratus) surviving in the barrens

Abstract Sea urchin grazing can drive kelp loss creating low productivity “barrens” with reduced biodiversity that may persist for decades. In these habitats, limited food driven by sea urchin herbivory reciprocally affects sea urchin physiology, yet the metabolic pathways enabling survival in the starvation conditions remain poorly understood. This study employed gas chromatography–mass spectrometry metabolomics to compare gonad metabolite profiles of purple sea urchins, Strongylocentrotus purpuratus , from barrens and adjacent kelp forest margins. Gonads from barren animals showed pronounced metabolic reallocations relative to kelp-margin animals, supporting energy production, redox balance, and membrane integrity. Carbohydrate metabolism was shifted towards increased glucose and gluconeogenesis with reduced alanine and glutamine as substrates for energy production. The pentose phosphate pathway fluxed towards energy production (supported by elevated sedoheptulose and mannoheptulose, and reduced glutamine and glutamate), rather than nucleotide synthesis and growth. Elevated amino acids (cysteine, cystine and lysine) reflected gonad protein catabolism, energy production and redox balance. Changes in lipid metabolism showed elevated monostearin from lipid breakdown, reduced heptanoic acid as energy substrate, and increased malonate supporting membrane integrity. This study reveals the specific metabolic adjustments purple sea urchins employ under food-limited conditions in barrens, diverting energy from reproduction to enhance long-term survival, potentially signaling challenges for kelp restoration.

The mediating role of sleep quality in the association between urinary incontinence and depressive symptoms: A study with older Korean Americans Living in Subsidized Senior Housing

Urinary incontinence (UI) is a prevalent health issue among older adults. Depressive symptoms often accompany UI; however, the pathways linking these conditions remain understudied. In this study, we conceptualized sleep quality as a potential mediator in the association between UI and depressive symptoms. The mental health burden of UI is anticipated to be indirectly associated with impaired sleep quality. The mediating role of sleep quality was tested in a sample of 306 older Korean Americans living in low-income senior housing (mean age = 79.4 years, range = 65–102). Regression analyses showed a significant association between UI and depressive symptoms. Mediation analysis using the Hayes PROCESS macro showed that the indirect effect of UI on depressive symptoms through sleep quality was significant (B [SE] = 0.59 [0.21], bias-corrected 95% CI = [0.20, 1.02]), accounting for approximately 24% of the total effect. The findings suggest that compromised sleep quality may serve as a potential pathway linking UI and depressive symptoms. Sleep quality should be addressed in efforts to promote the mental health of older adults experiencing UI.

Phosphor‐Sensitized Deep Blue Narrowband OLED Devices With EQE Over 40% by Using a Horizontal‐Oriented Host

ABSTRACT Phosphor‐sensitized blue multiple resonance thermally activated delayed fluorescence (MR‐TADF) devices represent a promising approach for simultaneously achieving high efficiency and color purity through rapid exciton conversion and narrowband emission. However, realizing such devices with external quantum efficiency (EQE) exceeding 40% remains a challenge due to limited light out‐coupling efficiency caused by low horizontal dipole ratios (Θ || ) of the emitters. Herein, we reported a new horizontal‐oriented host 4CzTPS developed by symmetrically linking two bicarbazole units to a tetraphenylsilane core to achieve a linear geometry, thereby inducing horizontal alignment on the substrate. Consequently, the designed host with strong positive electrostatic potential at the tetraphenylsilane core attracts the emitter D1‐DBN with negative electrostatic potential on the B/N core through electrostatic interaction, yielding a high Θ || of 94.5% and enabling the phosphor‐sensitized blue device to achieve an EQE of 40.5%. Furthermore, by using an exciplex‐type co‐host based on 4CzTPS to decrease electron injection barrier and balance charge transport, the blue device achieved a record‐breaking EQE of 42.0%, narrowband emission with a small full width at half‐maximum of 16.2 nm, deep blue CIE coordinates of (0.116, 0.112), and the operational stability with a LT 50 of 3483 h at an initial luminance of 100 cd m −2 .

Hybrid frequency-domain CFAR detectors for cognitive radio interference resilience and the dual-use security paradox

Abstract Cognitive radio networks (CRNs) enable secondary users (SUs) to opportunistically access underutilized licensed spectrum while protecting primary users (PUs). Robust spectrum sensing under heterogeneous interference and heavy jamming remains challenging: conventional approaches either require extensive prior knowledge or degrade significantly under interference, while basic constant false-alarm rate (CFAR) variants remain vulnerable to structured jamming that contaminates only part of the reference window, causing fixed-rule estimators to either include contaminated samples or discard clean ones. Hybrid CFAR architectures address this by first analyzing reference-window contamination patterns and then adaptively selecting or combining estimation strategies. We adapt eleven such hybrid architectures—originally developed in the radar literature—to frequency-domain spectrum sensing in contested CRNs, and evaluate them across four families (adaptive algorithm selection, order-statistic fusion, intelligent censoring, and weighted processing) against classical CR-CFAR baselines via Monte Carlo simulations using APCO Project 25 as the PU waveform and an OFDMA-based SU, under barrage and swept-FM jamming. Results show that First-Order Difference CFAR achieves the best detection performance through global sorting and statistical jump detection ( $$P_{\text{d}} \approx 1$$ at SNR  $$= 3$$  dB under 50% sweep coverage), followed by Smallest-Of and Order-Statistic Smallest-Of variants. However, this resilience creates a dual-use security paradox: unauthorized devices employing these techniques can resist administrative spectrum control. We address this through an algorithm-aware comb-sweep countermeasure that exploits CFAR reference-window dependencies, inducing near-unity false alarms on vacant channels within a 4 dB JSR denial plateau ( $$-5$$ to $$-1$$  dB) while preserving PU detection, demonstrating that algorithm-aware enforcement can restore spectrum governance in contested environments.

Lessons learned from youth-engaged research methods to conduct qualitative analysis with a transgender and gender-diverse youth advisory board

Although community-engaged research is becoming more common, youth-engaged research methods, particularly its application to qualitative analysis, remains rare. The Research on Identity Specific Eating Disorder Symptoms (RISES) Project developed, partnered with, and maintained a youth advisory board of five transgender, non-binary, and gender-diverse youth in all stages of a qualitative study, including qualitative analysis. Youth advisory board members contributed to a codebook, coded two to six transcripts each, provided feedback on themes and supporting quotes, and authored this paper. After one year, we achieved a retention rate of 83.3% of all youth advisory board members, and 100% of youth advisory board members trained in qualitative analysis. This paper describes the lessons learned from partnering with and training a transgender, non-binary, and gender-diverse youth advisory board to conduct qualitative analysis.

Supercritical CO ₂ ‐Modulated Surface Amorphization and O _V Defect in CaSnO ₃ for High‐Efficiency Electrocatalytic H ₂ O ₂ Production

ABSTRACT The electrochemical two electron water oxidation reaction (2e‐WOR) offers a promising route for hydrogen peroxide (H 2 O 2 ) production, but its efficiency is limited by the lack of high performance electrocatalysts. Herein, we report a supercritical carbon dioxide (SC CO 2 ) modulation strategy to synergistically engineer surface amorphization and oxygen vacancy (O V ) defects in orthorhombic CaSnO 3 . Under an optimal SC CO 2 pressure of 16 MPa, the treated CaSnO 3 exhibits a partially amorphized surface, abundant O V , and concomitant Sn 3+ defects. These features collectively increase unsaturated coordination sites, accelerate interfacial charge transfer, and lower the reaction overpotential. Consequently, the optimal catalyst achieves a H 2 O 2 production rate of 26.6 µmol cm− 2 min −1 , a Faradaic efficiency (FE) of 82% at 2.9 V versus RHE, and a cumulative yield over 300 min approximately eight times that of pristine CaSnO 3 , with stable operation for 24 h. This work demonstrates that SC CO 2 treatment is an effective tool to construct defect coupled surface amorphous regions, providing a new paradigm for designing high ‐ performance 2e‐WOR electrocatalysts for green H 2 O 2 synthesis.

Finite-time composite dynamic compensation control for USVs with rotatable thrusters and multi-channel event-triggered inputs under thruster faults