Energetics, but not development, is impacted in coral embryos exposed to ocean acidification

In light of the chronic stress and mass mortality reef-building corals face under climate change, it is critical to understand the processes driving reef persistence and replenishment, including coral reproduction and development. Here we quantify gene expression and sensitivity to ocean acidification across a set of developmental stages in the rice coral, Montipora capitata. Embryos and swimming larvae were exposed to pH treatments 7.8 (Ambient), 7.6 (Low) and 7.3 (Xlow) from fertilization to 9 days post-fertilization. Embryo and larval volume, and stage-specific gene expression were compared between treatments to determine the effects of acidified seawater on early development. While there was no measurable size differentiation between pH treatments at the fertilized egg and prawn chip (9 hours post-fertilization) stages, early gastrulae and larvae raised in reduced pH treatments were significantly smaller than those raised in ambient seawater, suggesting an energetic cost to developing under low pH. However, no differentially expressed genes were found until the swimming larval stage. Notably, gene expression patterns of larvae developing at pH 7.8 and pH 7.3 were more similar than those developing at pH 7.6. Larvae from pH 7.6 showed upregulation of genes involved in cell division, regulation of transcription, lipid metabolism, and response to oxidative stress in comparison to the other two treatments. While low pH appears to increase energetic demands and trigger oxidative stress in larvae, the developmental process is robust to this at a molecular level, with the swimming larval stage reached in all pH treatments.

The spectral quality of light is a key driver of photosynthesis and photoadaptation in Stylophora pistillata colonies from different depths in the Red Sea

Depth zonation on coral reefs is largely driven by the amount of downwelling, photosynthetically active radiation (PAR) that is absorbed by the symbiotic algae (zooxanthellae) of corals. The minimum light requirements of zooxanthellae are related to both the total intensity of downwelling PAR and the spectral quality of the light. Here we used Stylophora pistillata colonies collected from shallow (3 m) and deep (40 m) water; colonies were placed in a respirometer under both ambient PAR irradiance and a filter that only transmits blue light. We found that the colonies exhibited a clear difference in their photosynthetic rates when illuminated under PAR and filtered blue light, with higher photosynthetic performance when deep colonies were exposed to blue light compared with full-spectrum PAR for the same light intensity and duration. By contrast, colonies from shallow water showed the opposite trend, with higher photosynthetic performances under full-spectrum PAR than under filtered blue light. These findings are supported by the absorption spectra of corals, with deeper colonies absorbing higher energy wavelengths than the shallow colonies, with different spectral signatures. Our results indicate that S. pistillata colonies are chromatically adapted to their surrounding light environment, with photoacclimation probably occurring via an increase in photosynthetic pigments rather than algal density. The spectral properties of the downwelling light are clearly a crucial component of photoacclimation that should be considered in future transplantation and photoacclimation studies.

Portable infusion pumps in ambulatory cancer chemotherapy

Fifty-seven adult patients receiving chemotherapy were treated with a total of 133 infusions using portable user-worn infusion pumps, the Autosyringe AS*2F Cormed ML6-4, and two earlier versions of the latter, the Sigmamotor ML6-2 and ML6-3. Ninety-eight infusions were given on an ambulatory basis. Fourteen infusions were given through peripheral venous catheters, 115 through central venous catheters, and four intra-arterially. Of 127 evaluable infusions, 65 were completed within 5% and 87 within 10% of the planned rate; results are similar for both inpatient and outpatient infusions. The Cormed ML6-4 pump was equal to the Autosyringe AS*2F in reliability but superior to the latter in patient preference. There were no instances of dangerously rapid administration of the drug. The only serious catheter complications were a pneumothorax after insertion of a subclavian catheter in one patient and cellulitis in a leukopenic patient with a Broviac catheter. All but three patients preferred outpatient therapy to hospitalization. Outpatient therapy costs about $300 per day less than in-hospital treatment.

Influence of Chemical Nature on Flow Behavior of Polymers. I. Shear Rate and Temperature Dependence

The flow behavior of low molecular weight liquid polybutadiene polymers was studied as a function of shear rate, temperature, and molecular structure. Measurements were made in the temperature range 15 to 50° C and shear rate range 1 to 15,000 sec−1 with a cone and plate and a capillary viscometer. Limiting low shear viscosity, flow activation energy, and critical shear rate marking onset of shear rate thinning were found to be strongly dependent upon the presence of functional groups such as hydroxyl, carboxyl, and nitrile. The modifying groups showed a greater effect than the molecular weight upon the properties measured.