Environmental ethics and medical ethics: some implications for end-of-life care, Part I

Heterotrimeric G proteins, consisting of alpha, beta, and gamma subunits, transduce environmental signals through coupling to plasma membrane-localized receptors. We previously reported that the filamentous fungus Neurospora crassa possesses a Galpha protein, GNA-1, that is a member of the Galphai superfamily. Deletion of gna-1 leads to defects in apical extension, differentiation of asexual spores, sensitivity to hyperosmotic media, and female fertility. In addition, Deltagna-1 strains have lower intracellular cAMP levels under conditions that promote morphological abnormalities. To further define the function of GNA-1 in signal transduction in N. crassa, we examined properties of strains with mutationally activated gna-1 alleles (R178C or Q204L) as the only source of GNA-1 protein. These mutations are predicted to inhibit the GTPase activity of GNA-1 and lead to constitutive signaling. In the sexual cycle, gna-1(R178C) and gna-1(Q204L) strains are female-fertile, but produce fewer and larger perithecia than wild type. During asexual development, gna-1(R178C) and gna-1(Q204L) strains elaborate abundant, long aerial hyphae, produce less conidia, and possess lower levels of carotenoid pigments in comparison to wild-type controls. Furthermore, gna-1(R178C) and gna-1(Q204L) strains are more sensitive to heat shock and exposure to hydrogen peroxide than wild-type strains, while Deltagna-1 mutants are more resistant. In contrast to Deltagna-1 mutants, gna-1(R178C) and gna-1(Q204L) strains have higher steady-state levels of cAMP than wild type. The results suggest that GNA-1 possesses several Gbetagamma-independent functions in N. crassa. We propose that GNA-1 mediates signal transduction pathway(s) that regulate aerial hyphae development and sensitivity to heat and oxidative stresses, possibly through modulation of cAMP levels.     

Gastrointestinal sutureless anastomosis using fibrin glue: reinforcement of the sliding absorbable intraluminal nontoxic stent and development of a stent placement device

Sutureless anastomosis of the gastrointestinal tract using fibrin glue and sliding absorbable intraluminal nontoxic stents (SAINTs) has two shortcomings, stent shaft breakage and the lack of a transanal insertion device (TID) for low anterior resection. Reinforcement of the sucrose base SAINT (R-SAINT) is described. Sutureless anastomosis is attempted using a stapleless mechanical stapler (SS) and used as preprototype to screen histologically and mechanically for TID anastomoses in the small intestine. Finally, a prototype absorbable head SAINT placement device (SAINT-PD) intended for TID, similar to the SS, is utilized on the small intestine. Fifty-seven Landrace pigs weighing 25-35 kg were used to perform 58 anastomoses, including the small intestine (15 manual, 19 SAINT, 11 SS, 5 R-SAINT, 6 SAINT-PD) and large intestine (2 R-SAINT). All anastomoses performed with the R-SAINT succeeded on the first attempt even if the shaft cracked. The SS technique proved impractical, but the histological screen results from 7 to 60 days did approximate those of corresponding SAINT anastomoses. The SAINT-PD demonstrated operational improvement over the SS, but the histological results were similar to both the SS and SAINT. The advantages of the R-SAINT and SAINT-PD are that they leave no foreign bodies or pressure clamping devices at the anastomostic site. Larger studies may show the R-SAINT and the SAINT-PD to be practical, new surgical tools in sutureless fibrin glue anastomosis.     

Packaging optimization using the dynamic vector fields method

In this paper, a novel packaging optimization method for convex objects is presented. This method solves the packaging optimization problem through dynamic simulation of object positions and rotations over time. Object positions and orientations are determined by dynamic vector fields, which accelerate objects according to optimization objectives or physical effects between objects or their environment. Using these vector fields, any number of objectives or effects can be accounted for, and this scalability allows the method to potentially be employed to solve a wide variety of engineering packaging optimization problems. The current implementation, as presented in this paper, represents the foundation of the method that future improvements will build upon and is currently limited to the analysis of convex objects. Three basic vector fields are presented to solve packing density maximization problems: the first maximizes packing density, the second prevents collisions between objects, and the third optimally orients objects relative to each other. Collisions between objects are relaxed in this method, allowing objects to pass through each other, which provides the potential for reduced initial condition dependence and has shown promising results thus far. Several test problems are presented and solved, demonstrating the method and its ability to generate optimal solutions.     

Diatoms abound in ice-covered Lake Erie: An investigation of offshore winter limnology in Lake Erie over the period 2007 to 2010

The limnology of offshore Lake Erie during periods of extensive (> 70%) ice cover was examined from ship borne sampling efforts in 2007 to 2010, inclusive. Dense and discrete accumulations of the centric filamentous diatom Aulacoseria islandica (> 10 μg Chl-a/L) were located in the isothermal (< 1 °C) water column directly below the ice and only detectable in the ship wake; viable phytoplankton were also observed within ice. Evidence from these surveys supports the notions that winter blooms of diatoms occur annually prior to the onset of ice cover and that the phytoplankton from these blooms are maintained in the surface waters of Lake Erie and reduce silicate concentrations in the lake prior to spring. The mechanisms by which high phytoplankton biomass rise at this time of year requires further investigation, but these winter blooms probably have consequences for summer hypoxia and how the lake responds to climate change.     

Color-accurate underwater imaging using perceptual adaptive illumination

Capturing color in water is challenging due to the heavy non-uniform attenuation of light in water across the visible spectrum, which results in dramatic hue shifts toward blue. Yet observing color in water is important for monitoring and surveillance as well as marine biology studies related to species identification, individual and group behavior, and ecosystem health and activity monitoring. Underwater robots are equipped with motor control for large scale transects but they lack sensors that enable capturing color-accurate underwater images. We present a method for color-accurate imaging in water called perceptual adaptive illumination. This method dynamically mixes the illumination of an object in a distance-dependent way using a controllable, multi-color light source. The color mix compensates correctly for color loss and results in an image whose color composition is equivalent to rendering the object in air. Experiments were conducted with a color palette in the pool and at three different coral reefs sites, and with an underwater robot collecting image data with the new sensor.     

Emotional states and physical health.

Positive emotional states may promote healthy perceptions, beliefs, and physical well-being itself. To explore potential mechanisms linking pleasant feelings and good health, the authors consider several lines of research including (a) direct effects of positive affect on physiology, especially the immune system, (b) the information value of emotional experiences, (c) the psychological resources engendered by positive feeling states, (d) the ways in which mood can motivate health-relevant behaviors, and (e) the elicitation of social support. As anticipated by the Greek physician Hippocrates, positive emotions and healthy outcomes may be linked through multiple pathways. (PsycINFO Database Record (c) 2010 APA, all rights reserved)