Pohang TechnoPark (South Korea)

ABSTRACT Self‐assembled monolayers (SAMs) have emerged as promising hole‐transporting layers (HTLs) for organic photovoltaics (OPVs). However, their practical application is often hindered by inherent aggregation issues and the difficulty of forming uniform thin films over large areas. To overcome these limitations, we developed a novel interfacial modification process using nicotinic hydrazide (NH) designed to eliminate residual SAM aggregates. We demonstrate that NH effectively eliminates the aggregated 2PACz by forming an energetically favorable complex with the phosphonic acid groups, yielding an uniform and aggregate‐free SAM layer. Comprehensive characterization confirms that this treatment enhances film quality and surface wettability, thereby improving the HTL/active layer interfacial contact. Integrating this optimized SAM into OPV devices leads to significantly improved efficiency of 15.38% using a blade‐coated 1 cm 2 active area, primarily due to improved charge extraction and reduced trap‐assisted recombination, which enhance both open‐circuit voltage and fill factor. Furthermore, the superior uniformity and reproducibility of NH‐treated HTL facilitates successful large‐area fabrication. As a result, the power conversion efficiency (PCE) of OPV modules are enhanced from 14.07% to 15.02%, and the resulting perovskite‐organic tandem module achieves a PCE of 19.89% at 16.41 cm 2 active area, demonstrating a robust pathway for high‐performance scalable photovoltaics.

ABSTRACT Electrocatalytic CO 2 reduction has emerged as a promising pathway toward carbon neutrality, with C 2 products attracting considerable interest due to their high economic value. However, the efficiency and selectivity of this process are limited by the high kinetic barrier of C─C coupling and strong competition from the hydrogen evolution reaction (HER). In this work, we propose a strategy to promote C─C coupling by constructing a local alkaline microenvironment and accordingly design and fabricate a heterojunction catalyst composed of SrO‐modified CuO (SrO/CuO). In‐depth investigations reveal that the incorporation of SrO enhances * CO intermediate coverage, facilitates the hydrogenation of * CO to * CHO, and promotes the subsequent asymmetric * CHO─ * CO coupling. More critically, SrO functions as an efficient water‐dissociation center, generating an OH − ‐enriched local microenvironment. This alkaline setting not only suppresses the competing HER but also stabilizes the C─C coupling transition state ( * CHO─ * CO) and provides ample * H to accelerate * CO hydrogenation, thereby greatly enhancing selective C 2 production. Electrochemical tests demonstrate that SrO/CuO achieves a high C 2 Faradaic efficiency of 71.4% at −1.5 V vs. RHE in a flow cell, while maintaining excellent stability over a wide potential window.

Photocatalytic CO2 conversion demands precise control over multielectron reaction pathways to achieve selective solar fuel production. Atomically dispersed Fe and Cu catalysts on TiO2 direct divergent photoreduction outcomes-CO via Fe and CH4/C2H6 via Cu-through modulation of CO intermediate binding. Using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), X-ray absorption fine structure (XAFS), and density functional theory (DFT) calculations, this study unveils how metal-support interactions reshape electronic structure, stabilize key intermediates, and create oxygen vacancies that enhance CO2 adsorption in the dark. The Cu sites further promote C─C coupling, enabling multicarbon products under mild conditions. The optimized single-atom catalysts show up to 55.7-fold enhancement in CO and 44.5-fold in CH4 yields, far surpassing pristine TiO2. This work illustrates how rational single-atom design can precisely manipulate reaction pathways at the atomic scale, offering a unified framework for selective photoredox catalysis in CO2 reduction.

The gut microbiota plays an essential role in mucosal immunity, with secretory immunoglobulin A (IgA) acting as a key effector in neutralizing pathogens and maintaining host-microbiota homeostasis. IgA production occurs via T cell-dependent (TD) and -independent pathways, with T follicular helper (Tfh) cells driving high-affinity, antigen-specific IgA responses. However, the specific microbial taxa and metabolites that regulate Tfh-mediated IgA responses under steady-state conditions remain poorly understood. This study investigated how gut microbiota-derived signals shape Tfh responses and IgA production, with implications for enhancing mucosal vaccine efficacy. We demonstrate that Peyer's patches (PP)-derived Tfh cells exhibit superior IgA-inducing capacity compared to splenic Tfh cells. RNA sequencing revealed distinct transcriptional profiles in PP-Tfh cells, including upregulation of the genes associated with Tfh differentiation and activation (Bcl6, Cd40lg, Maf), T-B cell interactions (Il21, Sh2d1a, Fyn), and migration (Ccr6, Cxcr5). Functionally, PP-Tfh cells formed larger T-B cell contact areas and induced significantly higher IgA secretion in co-culture than their splenic counterparts. Microbiota depletion experiments revealed that eliminating neomycin-depleted bacteria reduced fecal IgA levels and diminished PP-Tfh cell frequencies. Fecal microbiota transplantation from neomycin-treated mice restored both IgA production and Tfh responses in germ-free (GF) mice. Bioinformatic analysis (PICRUSt2 and LEfSe) identified butyrate-producing Lachnospiraceae and Ruminococcaceae as key drivers of the Tfh-IgA axis. Butyrate supplementation enhanced Tfh differentiation and IgA⁺ germinal center B cell development in vitro and increased fecal IgA levels in vivo. Mechanistically, butyrate promoted IgA production via GPR43 signaling, as its effect was lost in co-cultures with Gpr43⁻/⁻ Tfh cells. Moreover, treatment with tributyrin, a butyrate prodrug, enhanced vaccine-induced IgA and protected mice against Salmonella Typhimurium infection, reducing bacterial burden and tissue damage. These findings define a functional microbiota-Tfh-IgA axis sustained by neomycin-depleted, butyrate-producing bacteria. Our study underscores the crucial role of the gut microbiota, particularly neomycin-depleted butyrate producing taxa, in regulating PP-Tfh cell function and IgA production. Butyrate emerges as a metabolite linking microbial metabolism to Tfh differentiation and IgA class switching. Together, these findings establish a microbiota-metabolite-Tfh cell axis essential for mucosal immune homeostasis and suggest novel strategies for enhancing vaccine efficacy and protection against enteric infections. Video Abstract.

A 70-year-old man was admitted to the Department of Rehabilitation Medicine of a university hospital for postoperative rehabilitation following the surgical treatment of spondylodiscitis.One month before admission, the patient was diagnosed with spondylodiscitis at the L3-L4 level, accompanied by spinal instability, for which debridement and posterior fixation from L1-L5 were performed.The spinal surgery was performed with the patient in the prone position.He had undergone kidney transplantation for end-stage chronic kidney disease 23 years previously with ongoing oral immunosuppressive therapy consisting of tacrolimus (1 mg twice daily), mycophenolate mofetil (500 mg twice daily), and prednisolone (5 mg once daily).The patient had no additional significant medical history.The patient reported weakness in the left hand accompanied by tingling pain localized to the ulnar aspect, which developed after the spinal surgery.The pain intensity was rated as 3 on the numeric rating scale.On physical examination, manual muscle testing revealed decreased strength of the left abductor digiti minimi muscle, corresponding to Medical Research Council grade 3. Sensory examination revealed hypoesthesia involving the fifth digit and medial side of the fourth digit.Froment's sign (Fig. 1A) and the crossed finger test (Fig. 1B) were positive on the left side but negative on the right side, indicating weakness of the left intrinsic hand muscles innervated by the ulnar nerve.Deep tendon reflexes of the biceps and triceps were normal and symmetric.Spurling's test and Tinel's sign at the wrist were negative, and no upper motor neuron signs, such as Hoffmann reflex, were observed.Provocative test results for thoracic outlet syndrome, including Roos and Adson's tests, were also negative. Differential diagnosisThe following potential diagnoses were considered to explain the patient's left-hand weakness and sensory disturbance.

Many biological tissues, such as cardiac muscle, tendons, and the cornea, exhibit highly organized microstructural alignment that is critical for mechanical and physiological functions. Disruptions in this structural organization are commonly associated with pathological conditions such as fibrosis, infarction, and cancer. However, conventional histological imaging techniques rely on immunofluorescence or histochemical staining, and they evaluate tissue alignment via non-physical 2D gradient-based calculation, which is labor-intensive, antibody-dependent, and prone to variability. Here, we demonstrate label-free mid-infrared dichroism-sensitive photoacoustic microscopy (MIR-DS-PAM), an analytical imaging system for cardiac tissue assessments. By combining molecular specificity with polarization sensitivity, this method selectively visualizes protein-rich engineered heart tissue (EHT) and quantifies the extracellular matrix (ECM) alignment without any labeling. The extracted dichroism-sensitive parameters, such as the degree of dichroism and the orientation angle, enable histostructural evaluation of tissue integrity and reveal diagnostic cues in fibrotic EHT. This technique offers a label-free analytical tool for fibrosis research and tissue engineering applications.

PERCIVAL, “pixellated energy-resolving CMOS imager versatile and large”, is a 2-megapixel soft X-ray imager developed for use at FELs and modern-day synchrotrons. A combination of capabilities is necessary to meet the scientific needs: a large, uninterrupted imaging area with small pixels, high dynamic range, high frame rate, and soft X-ray suitable entrance window to the sensor. A single PERCIVAL sensor offers over 4 cm × 4 cm uninterrupted imaging area (1408 × 1484 pixels of 27 × 27 μm2). Three auto-adapting gains (per pixel per image) provide the large dynamic range from 13 e- noise to over 3 Me- signal. The sensor is designed for up to 300 Hz frame rate, and can be operated faster in ROI mode.The first generation of the sensor was hampered by severe crosstalk preventing parallel operation of ADC, streamout, and pixel switches and by non-uniformity of baselines over the sensor.A revised “respin” sensor addresses these issues at the root — and good noise performance at higher frame rates as well as a more uniform baseline can now be provided to users.The first generation DAQ system — still based on existing Virtex5 hardware — had limitations that ultimately prevented handling the fast data rates from a Percival running at full speed, or other complexities such as ROI operation. A complete overhaul of the percival-specific DAQ components (FPGA with periphery and firmware) today enables acquisition at envisioned frame rates and in ROI mode.This paper summarizes first laboratory results from the respin sensors in combination with the new DAQ hardware and firmware.