Origin and evolution of osmoregulatory mechanisms in blue-green algae (cyanobacteria) as a function of metabolic and structural complexity: Reflections of Precambrian paleobiology

Major accomplishments underlying the basic understanding of cyanobacterial resistance to salt tolerance and osmotic stress were made. The methodology proposed included: the tracing of the pathways of formation of osmoregulatory solutes by traditional methods involving C-14 labelled substrates; gas chromatography; amino acid analysis; X-ray analysis using scanning transmission electron microscopy; and most importantly, C-13 labelled substrates, followed by Nuclear Magnetic Resonance (NMR) spectroscopy. It was found that the cyanobacteria employ a diversity of organic, osmoregulatory solutes. Osmoregulatory solutes were found to serve four functions: adjustment of water activity, noninhibition of enzymes; lowering of K sub m of enzymes to allow functioning at normal levels when the intracellular salt accumulates, and extending the pH optimum of enzymes as intracellular pH rises due to proton-potassium ion pump action during osmoregulation. Differences in osmoregulatory solutes may, but are not always, be attributed to differences in nutritional capabilities. The mechanism of osmoregulation and concomitant salt tolerance in halophilic cyanobacteria was elucidated. The activities of betaine and S-Adenosylhomocysteine hydrolase are discussed

Use of Hydroponics to Maintain Quality of Recirculated Water in a Fish Culture System

Fish production, biofiltration, and hydroponics were linked in a closed system of recirculating water. Fish tanks were stocked with channel catfish (Ictalurus punctatus) and the fish were fed daily. A revolving plate-type biofilter was used. Three field varieties of tomatoes (Lycopericon esculentum) were planted in outdoor hydroponic tanks. Three production units were operated during the 1976 growing season. All significant water quality variables were monitored. Performance was evaluated in terms of water quality, vegetative and fruit production of the tomatoes, and growth of the fish. Fish survival was high, but growth was below maximum because the temperature in the system was below optimum. The average loading rate of fish for the three units at harvest was 31.5 kg/unit, 489 g/tomato plant, 1.9 kg/m2 of hydroponic area, and 691 g/m2 of biofilter surface. Excellent water quality was maintained. The biofilter satisfactorily converted the waste to nitrate-N and phosphate-P and the hydroponic system removed these end products from the water. Nutrients were periodically added to supplement the nutrients from fish waste. Tomato yield was approximately twice that either demonstrated or expected in field production of the same varieties, and the hydroponically produced tomatoes were of better quality than the same varieties grown under field conditions

Predictors and outcomes of converted minimally invasive pancreaticoduodenectomy: a propensity score matched analysis

Background Data-driven patient selection guidelines are not available to optimize outcomes in minimally invasive pancreaticoduodenectomy (MIPD). We aimed to define risk factors associated with conversion from MIPD to open PD and to determine the impact of conversion on post-operative outcomes. Methods We conducted a retrospective review of MIPD using NSQIP from 2014 to 2015. Propensity score was used to match patients who underwent completed MIPD to converted MIPD. Results 467 patients were included: 375 (80.3%) MIPD and 92 (19.7%) converted. Converted patients were more often male (64% vs. 52%, p = 0.030), had higher rates of dyspnea (10% vs. 3%, p = 0.009), underwent more vascular (44% vs. 14%, p < 0.001) or multivisceral resection (19% vs. 6%, p = 0.0005), and were more likely attempted laparoscopically compared to robotically (76% vs. 51%, p < 0.001). Robotic approach was independently associated with reduced risk of conversion (OR 0.40, 95% CI 0.23-0.69), while male gender (OR 1.70, 95% CI 1.02-2.84), history of dyspnea (OR 3.85, 95% CI 1.49-9.96), vascular resection (OR 4.32, 95% CI 2.53-7.37), and multivisceral resection (OR 2.18, 95% CI 1.05-4.52) were associated with increased risk. Major complications were more common in converted patients (68% vs. 37%, p < 0.001). Converted patients had increased odds of non-home discharge (OR 3.25, 95% CI 1.06-9.97) and an associated increased length of stay of 3 days (95% CI 0.1-6.7). Conclusion Patients with a history of dyspnea or tumors requiring vascular or multivisceral resection were at increased risk of conversion, and the robotic platform was associated with a lower rate of conversion. Conversion was independently associated with increased overall complications, increased length of stay, and non-home discharge