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Laser powder bed fusion of copper-bearing AISI 316 L: Microstructure, biofunctional and corrosion performance

2025-11-10T07:13:37Z

Title: Laser powder bed fusion of copper-bearing AISI 316 L: Microstructure, biofunctional and corrosion performance Authors: Behjat, Amir; Norouzi, Ehsan; Kharaziha, Mahshid; Suh, Jin-Yoo; Bagherifard, Sara; Khorramian, Mahta; Saboori, Abdollah Abstract: Developing strategies to impart antibacterial properties to biomaterials while preserving cytocompatibility is essential for addressing implant-associated infections. In this study, copper-alloyed AISI 316 L stainless steel produced by laser powder bed fusion (L-PBF) was investigated as a dual-functional biomaterial with both antibacterial and cytocompatible characteristics. Unlike previous studies that mainly focus on bulk composition, this study emphasizes the role of microstructural features unique to L-PBF processing, specifically copper micro-segregation at cellular boundaries and nanoscale oxides and examines how these influence electrochemical behavior and biological responses. Electrochemical tests suggest that the AISI 316 L-Cu samples exhibit corrosion behavior comparable to that of conventional AISI 316 L. Nevertheless, the addition of Cu resulted in diminished pitting resistance, which subsequently affected the characteristics of the passive film. Importantly, AISI 316 L-Cu demonstrate significant antibacterial activity against both Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). Moreover, AISI 316 L-Cu reveals in vitro bioactivity and cytocompatibility in contact with osteoblast-like MG63 cells, supporting cell proliferation and spreading. The daily release of copper ions in physiological saline solution is measured at a trace level of parts per billion (2.5 ppb/cm2), which is considered to pose minimal risk to human health. In summary, AISI 316 L-Cu exhibited a strong capacity to enhance both antibacterial properties and cytocompatibility, suggesting a distinct advantage for its application in orthopedic settings.

Programmable FPGA-based TDLAS-WMS hygrometer (PFTWH) for broad-range water vapour detection: Quantitative assessment of digital lock-in amplifier (DLIA) performance via integrated WMS system (I-WMS)

2025-11-10T07:00:19Z

Title: Programmable FPGA-based TDLAS-WMS hygrometer (PFTWH) for broad-range water vapour detection: Quantitative assessment of digital lock-in amplifier (DLIA) performance via integrated WMS system (I-WMS) Authors: Choi, Minyoung; Cho, Gyuwon; Hwang, Seyeon; Lee, Jinwoo; Kim, Yangmo; Kim, Jeongmin; Kim, Kyunghoon; So, Hongyun; Choi, Sun Abstract: This study demonstrates the capability of wavelength modulation spectroscopy (WMS) based on tunable diode laser absorption spectroscopy (TDLAS) using a hand-held field-programmable gate array (FPGA) system. Programmable FPGA-based TDLAS-WMS hygrometer (PFTWH) enables measurement of water vapour concentrations over a broad range (70？5800？ppm) for applications in climate science. This system incorporates a custom-designed digital lock-in amplifier (DLIA), optimized for water vapour detection. For the DLIA, a 100？Hz cut-off frequency and a finite impulse response filter with a windowed-Hamming design and a 200-tap coefficient were used. The PFTWH demonstrated simultaneous processing capability of 1？f and 2？f signals by programming the DLIA on a commercial FPGA board. To quantitatively evaluate DLIA performance, we introduced an integrated WMS system that enables parallel operation of a commercial FPGA-based TDLAS-WMS hygrometer (CFTWH), the PFTWH, and direct TDLAS (dTDLAS). The 1？f and 2？f signals are extracted from both the CFTWH and PFTWH, while the dTDLAS provides reference concentration information for performance assessment. The linearity and accuracy of the designed PFTWH were validated by comparison with the CFTWH. Additionally, long-term measurements of water vapour concentrations across the broad range (70？5800？ppm) were successfully performed with a time resolution of 0.1？s, maintaining stable performance over 1000？s with 30？s averaging. Furthermore, both PFTWH and CFTWH were demonstrated to meet uncertainty, accuracy, and precision requirements for airborne measurement.

Hemoglobin as a pseudoperoxidase and drug target for oxidative stress-related diseases

2026-02-19T00:30:30Z

Title: Hemoglobin as a pseudoperoxidase and drug target for oxidative stress-related diseases Authors: Won, Woojin; Lee, Elijah Hwejin; Gotina, Lizaveta; Chun, Heejung; Lee, Jae-Hun; Bhalla, Mridula; Park, Uiyeol; Kim, Daeun; Kim, Tai Young; Choi, Ji Won; Kim, Yoowon; Park, Sun Jun; Lim, Jiwoon; Park, Jong-Hyun; Kim, Hyeon Jeong; Heo, Jun Young; Chung, Woosuk; Oh, Myung Jin; An, Hyun Joo; Lee, Junghee; Oh, Soo-Jin; Ryu, Hoon; Pae, Ae Nim; Park, Ki Duk; Lee, C. Justin Abstract: Hemoglobin (Hb) is well known for transporting oxygen in the blood, but its role in the brain remains poorly understood. Here, we identified Hb in the cytosol, mitochondria, and nuclei of hippocampal and substantia nigra astrocytes and dopaminergic neurons. As a pseudoperoxidase, Hb decomposes hydrogen peroxide (H2O2) and mitigates H2O2-induced oxidative damage. However, in Alzheimer’s disease, Parkinson’s disease, and aging, excessive H2O2 diminishes astrocytic Hb, perpetuating a vicious cycle of oxidative stress and neurodegeneration. To counter the harmful effects of aberrant H2O2 production in diseases, we developed KDS12025, a BBB-permeable small molecule that enhances Hb pseudoperoxidase activity 100-fold, even at a low level of Hb. KDS12025 and its analogs achieve this enhancement through its electron-donating amine group, possibly stabilizing the complex between Hb, H2O2, and KDS12025. KDS12025 reduces astrocytic H2O2, alleviates astrogliosis, normalizes Hb, and reverts to a virtuous cycle of redox balance, preventing neurodegeneration without altering the oxygen-transport function of Hb. Gene silencing of Hb abrogates the impact of KDS12025 in both culture and animal models, confirming the necessity of Hb for the effects of KDS12025. KDS12025 extends survival and improves motor function even in severe amyotrophic lateral sclerosis and aging. Furthermore, the enrichment of astrocytic Hb in the nucleolus highlights a novel antioxidative mechanism potentially protecting against nuclear oxidative damage. Our findings suggest that Hb is a new therapeutic target for neurodegenerative diseases, with KDS12025 emerging as a first-in-class approach that enhances Hb pseudoperoxidase activity to reduce H2O2. Increasing Hb pseudoperoxidase activity with KDS12025 mitigates oxidative stress and alleviates neurodegeneration in AD, PD, and ALS patients and increases the degree of aging, with broad applicability for numerous oxidative-stress-driven diseases.

Sulfonated polybenzimidazole for low-alkalinity ion solvating membrane water electrolysis

2026-02-20T09:07:00Z

Title: Sulfonated polybenzimidazole for low-alkalinity ion solvating membrane water electrolysis Authors: Mara , Muhammad Ikhsan; Yang, Chaeyeon; Ghotia, Kamal; Egert, Franz; Ansar, Syed-Asif; Żurowska, Olga; Rózga,, Maria; Michalak, Artur; Kraglund, Mikkel Rykær; Aili, David; Park, Hyun S.; Razmjooei, Fatemeh; Henkensmeier, Dirk Abstract: Ion solvating membranes based on polybenzimidazole (PBI) are alternatives to diaphragms in alkaline water electrolysers but can typically only operate with electrolyte concentrations of 15-30 wt% KOH. Sulfonation of the membrane broadens the operational range to 0.1 wt%-30 wt%; however, the swelling of sulfonated para-PBI means that crosslinkers are needed, complicating membrane fabrication and decreasing alkaline stability. Here we report a non-crosslinked PBI membrane with a 50% degree of sulfonation that shows a high room temperature conductivity in 1 M KOH of 135 mS cm-1. We did not observe degradation in a 6-month alkaline stability test at 80 °C. Using this membrane in an anion-exchange membrane water electrolyser, we report a current density of 4.8 A cm-2 at 2 V (3 M KOH at 80 °C; Pt and NiFe electrode catalysts); the H2 crossover to the O2 side remained <2%. Using non-platinum group metal electrodes and a polyphenylene sulfide-reinforced membrane, a cell operated for >1,000 h without failure. 1Center for