Photosystem II (PSII) uses light energy to oxidize water and to reduce plastoquinone in the photosynthetic electron transport chain. O is produced as a byproduct. While most members of the PSII research community agree that O originates from water molecules, alternative hypotheses involving bicarbonate persist in the literature. In this perspective, we provide an overview of the important roles of bicarbonate in regulating PSII activity and assembly. Further, we emphasize that biochemistry, spectroscopy, and structural biology experiments have all failed to detect bicarbonate near the active site of O evolution. While thermodynamic arguments for oxygen-centered bicarbonate oxidation are valid, the claim that bicarbonate is a substrate for photosynthetic O evolution is challenged.
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http://dx.doi.org/10.1007/s11120-024-01111-8 | DOI Listing |
Nutrients
December 2024
School of Physical Education and Sports Science, South China Normal University, Guangzhou 510006, China.
Background: Nutritional supplements are widely used by swimmers, but the effectiveness of various supplements and the identification of the most effective intervention require further investigation.
Purpose: This paper evaluated and compared the effectiveness of various nutrition-based interventions on swimming performance through both direct and indirect comparisons.
Methods: PubMed, Embase, Web of Science, Cochrane Library, and SPORTDiscus databases were thoroughly searched up to 4 April 2024.
Postgrad Med J
January 2025
Department of Obstetrics and Gynecology, Chung Shan Hospital, No. 11, Ln. 112, Sec. 4, Ren'ai Rd., Da'an Dist., Taipei City 10689, Taiwan.
Background: Our study aims to evaluate the umbilical vein (UV) hemodynamic change in the prenatal cohort of pregnancies diagnosed with abnormal placental cord insertion (aPCI).
Methods: From January 2022 to December 2022, the fetal umbilical cord insertion site was sonographically examined in singleton fetuses, and umbilical cord blood flow was calculated. The umbilical artery and UV Doppler flow indexes were assessed in cases of normal and abnormal cord insertion.
Chemosphere
January 2025
, School of Water Resources Engineering, Jadavpur University, Kolkata 700032, West Bengal, India. Electronic address:
Groundwater toxicity and water level depletion are serious concerns today. Assessing groundwater quality (GWQ) is crucial for effective planning and management due to increasing demands for drinking and irrigation water. Therefore, this study aims to analyze groundwater hydrochemistry, variability, and factors influencing quality for drinking and irrigation purposes using indices and models.
View Article and Find Full Text PDFEcotoxicol Environ Saf
January 2025
Institute of Combined Injury, State Key Laboratory of Trauma and Chemical Poisoning, Military Key Laboratory of Nanomedicine, Department of Military Preventive Medicine, Army Medical University, Chongqing 400038, China. Electronic address:
Uranium poisoning, particularly from exposure to Depleted Uranium (DU), occurs when uranyl ions enter the bloodstream and bind primarily to transferrin, osteopontin, and albumin before entering cells via corresponding receptors on renal tubular membranes, leading to cellular damage. Uranium poisoning remains a significant clinical challenge, with no ideal treatment currently available. In this study, we investigate the therapeutic potential of human umbilical cord-derived mesenchymal stem cell exosomes (MSC-EXs) in mice exposed to DU.
View Article and Find Full Text PDFJ Clin Neurosci
January 2025
Department of Neurology, Beijing Shunyi Hospital, Beijing 101300, PR China. Electronic address:
Background: This study aims to identify the factors influencing the risk of lactic acidosis (LA) in patients with ischemic stroke (IS) and to develop a predictive model for assessing the risk of LA in IS patients during their stay in the intensive care unit (ICU).
Methods: A retrospective cohort design was employed, with data collected from the Medical Information Mart for Intensive Care (MIMIC)-III and MIMIC-IV databases spanning from 2001 to 2019. LA was defined as pH < 7.
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