https://www.selleckchem.com/products/4-phenylbutyric-acid-4-pba-.html Photosynthetic production of molecular hydrogen (H2 ) by cyanobacteria and green algae is a potential source of renewable energy. These organisms are capable of water biophotolysis by taking advantage of photosynthetic apparatus that links water oxidation at Photosystem II and reduction of protons to H2 downstream of Photosystem I. Although the process has a theoretical potential to displace fossil fuels, photosynthetic H2 production in its current state is not yet efficient enough for industrial applications due to a number of physiological, biochemical, and engineering barriers. This article presents a short overview of the metabolic pathways and enzymes involved in H2 photoproduction in cyanobacteria and green algae and our present understanding of the mechanisms of this process. We also summarize recent advances in engineering photosynthetic cell factories capable of overcoming the major barriers to efficient and sustainable H2 production. To determine whether the severity of obstructive sleep apnea (OSA) is affected by weight gain velocity (WGV) in adolescents with Down syndrome. Retrospective case series. We performed a retrospective case series of children with Down syndrome, aged 9-19, referred for polysomnography (PSG) due to suspected OSA at an academic children's hospital. We determined the velocity (slope of change) of yearly weight gain using a mixed effect linear regression model. Subsequently, we determined if velocity of yearly weight gain was greater in adolescents with severe OSA (apnea-hypopnea index > 10). Significance was set at P < .05. A total of 77 adolescents with Down syndrome were identified. The average age was 12.5 years (standard deviation = 3.1); 44 (57%) were male and 46 (60%) were Hispanic. The majority, 51 (66%) had severe OSA. The velocity of yearly weight gain prior to PSG in Down syndrome adolescents was similar regardless of OSA severity (mean diff in weight g