Cyclic Stretch Induces Inducible Nitric Oxide Synthase and Soluble Guanylate Cyclase in Pulmonary Artery Smooth Muscle Cells

In the pulmonary vasculature, mechanical forces such as cyclic stretch induce changes in vascular signaling, tone and remodeling. Nitric oxide is a potent regulator of soluble guanylate cyclase (sGC), which drives cGMP production, causing vasorelaxation. Pulmonary artery smooth muscle cells (PASMCs) express inducible nitric oxide synthase (iNOS), and while iNOS expression increases during late gestation, little is known about how cyclic stretch impacts this pathway. In this study, PASMC were subjected to cyclic stretch of 20% amplitude and frequency of 1 Hz for 24 h and compared to control cells maintained under static conditions. Cyclic stretch significantly increased cytosolic oxidative stress as compared to static cells (62.9 ± 5.9% vs. 33.3 ± 5.7% maximal oxidation), as measured by the intracellular redox sensor roGFP. Cyclic stretch also increased sGCβ protein expression (2.5 ± 0.9-fold), sGC activity (1.5 ± 0.2-fold) and cGMP levels (1.8 ± 0.2-fold), as well as iNOS mRNA and protein expression (3.0 ± 0.9 and 2.6 ± 0.7-fold, respectively) relative to control cells. An antioxidant, recombinant human superoxide dismutase (rhSOD), significantly decreased stretch-induced cytosolic oxidative stress, but did not block stretch-induced sGC activity. Inhibition of iNOS with 1400 W or an iNOS-specific siRNA inhibited stretch-induced sGC activity by 30% and 68% respectively vs. static controls. In conclusion, cyclic stretch increases sGC expression and activity in an iNOS-dependent manner in PASMC from fetal lambs. The mechanism that produces iNOS and sGC upregulation is not yet known, but we speculate these effects represent an early compensatory mechanism to counteract the effects of stretch-induced oxidative stress. A better understanding of the interplay between these two distinct pathways could provide key insights into future avenues to treat infants with pulmonary hypertension.     

Automated cell classification and visualization for analyzing remyelination therapy

Remyelination therapy is a state-of-the-art technique for treating spinal cord injury (SCI). Demyelination—the loss of myelin sheath that insulates axons, is a prominent feature in many neurological disorders resulting in SCI. This lost myelin sheath can be replaced by remyelination. In this paper, we propose an algorithm for efficient automated cell classification and visualization to analyze the progress of remyelination therapy in SCI. Our method takes as input the images of the cells and outputs a density map of the therapeutically important oligodendrocyte-remyelinated axons (OR-axons) which is used for efficacy analysis of the therapy. Our method starts with detecting cell boundaries using a robust, shape-independent algorithm based on iso-contour analysis of the image at progressively increasing intensity levels. The detected boundaries of spatially clustered cells are then separated using the Delaunay triangulation based contour separation method. Finally, the OR-axons are identified and a density map is generated for efficacy analysis of the therapy. Our efficient automated cell classification and visualization of remyelination analysis significantly reduces error due to human subjectivity. We validate the accuracy of our results by extensive cross-verification by the domain experts.     

Easy detectable isocyanate in the reaction with gelatin

Gelatin reactivity with isocyanate was studied by using the easy detectable 1-naphthyl-isocyanate (NphI). Four different NphI/gelatin feed ratios were investigated with NphI molar amount ranging between 1/10 and 1/1 with respect to the possible reactive groups of gelatin. The reactions were carried out at 45 °C in DMSO as solvent, under nitrogen atmosphere. Modified gelatin samples were characterized by IR, UV–VIS, fluorescence spectroscopies as well as by proton and DOSY NMR. Spectroscopy results allow to evidence the presence of both bonded and unbonded naphthyl derivatives in the gelatin samples. Unbonded species were present particularly at the highest NphI/gelatin feed ratio and their formation was correlated to the increasing competition of the reaction with water since the amount of available reactive groups on gelatin was comparable or smaller than the amount of residuum water in dry gelatin.     

“A pig and a garden”: Fannie Lou Hamer and the Freedom Farms Cooperative

Much of the scholarship on the work and legacy of activist Fannie Lou Hamer concentrates on her tireless efforts for civil/human rights and African American representation and access to electoral politics. This article brings to light an important project she started in 1969, Freedom Farms Cooperative (FFC) in Sunflower County, MS. An agricultural cooperative built on 680-acres, Freedom Farms included a pig bank, Head Start program, community gardens, commercial kitchen, a garment factory, sewing cooperative, tool bank, and low-income, affordable housing as strategies to support the needs of African Americans who were fired and evicted for exercising the right to vote. Freedom Farms offered these sharecroppers and tenant farmers educational and re-training opportunities including health care and disaster relief for those who wanted to stay in the Mississippi Delta. Using a historical method to analyze extensive archival records, this article offers an analysis of Freedom Farms and illuminates valuable lessons on agriculture as resistance, and alternative strategies of rebuilding and investing in sustainable communities. Using the principles of collective and shared ownership, Freedom Farms and the work of Ms. Hamer, offer us important and valuable lessons on rebuilding our communities and investing in sustainable cities around growing food. This article outlines some of these lessons.     

Integrated microfluidic system enabling (bio)chemical reactions with on-line MALDI-TOF mass spectrometry

A continuous flow micro total analysis system (micro-TAS) consisting of an on-chip microfluidic device connected to a matrix assisted laser desorption ionization [MALDI] time-of-flight [TOF] mass spectrometer (MS) as an analytical screening system is presented. Reaction microchannels and inlet/outlet reservoirs were fabricated by powderblasting on glass wafers that were then bonded to silicon substrates. The novel lab-on-a-chip was realized by integrating the microdevice with a MALDI-TOFMS standard sample plate used as carrier to get the microfluidic device in the MALDI instrument. A novel pressure-driven pumping mechanism using the vacuum of the instrument as a driving force induces flow in the reaction microchannel in a self-activating way. Organic syntheses as well as biochemical reactions are carried out entirely inside the MALDI-MS ionization vacuum chamber and analyzed on-line by MALDI-TOFMS in real time. The effectiveness of the micro-TAS system has been successfully demonstrated with several examples of (bio)chemical reactions.     

Constraining accommodative homunculi in evolutionary explorations of jealousy: A reply to Barrett et al. (2006).

This article responds to a critique by H. C. Barrett, D. A. Frederick, M. G. Haselton, and R. Kurzban (see record 2006-10940-009), wherein it is argued that manipulations of cognitive constraints cannot be used to test general evolutionary hypotheses regarding the architecture of mind. In making this argument, Barrett et al. focus on what they believe to be faulty logic in D. DeSteno, M. Y. Bartlett, J. Braverman, and P. Salovey's (see record 2002-18731-006) use of such techniques to examine proposed sex differences in jealousy. In presenting their argument, however, Barrett et al. appear to disregard central findings presented in DeSteno et al. (2002) and, in so doing, fail to grasp the interrelations among findings that might readily address their concerns. Here, the authors present arguments for why and when manipulations of cognitive resources may prove useful in investigating evolved psychological mechanisms and, in so doing, situate their use within the ongoing debate concerning evolved sex differences in jealousy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Real people and virtual bodies: How disembodied can embodiment be?

It is widely accepted that embodiment is crucial for any self-aware agent. What is less obvious is whether the body has to be real, or whether a virtual body will do. In that case the notion of embodiment would be so attenuated as to be almost indistinguishable from disembodiment. In this article I concentrate on the notion of embodiment in human agents. Could we be disembodied, having no real body, as brains-in-a-vat with only a virtual body? Thought experiments alone will not suffice to answer this Cartesian question. I will draw on both philosophical arguments and empirical data on phantom phenomena. My argument will proceed in three steps. Firstly I will show that phantom phenomena provide a prima facie argument that real embodiment is not necessary for a human being. Secondly I will give a philosophical argument that real movement must precede the intention to move and to act. Agents must at least have had real bodies once. Empirical data seems to bear this out. Finally, however, I will show that a small number of aplasic phantom phenomena undermines this last argument. Most people must have had a real body. But for some people a partly virtual, unreal, phantom body seems to suffice. Yet though there is thus no knockdown argument that we could not be brains-in-a-vat, we still have good reasons to suppose that embodiment must be real, and not virtual.     

Collapse of the Magnetic Hyperfine Structure of Barium Hexaferrite by Mechanochemical Activation

The collapse of the magnetic hyperfine structure of barium hexaferrite as an effect of mechanochemical activation was investigated. The various inequivalent sites and phases present in the milled material were studied by transmission Mössbauer spectroscopy. Barium hexaferrite nanoparticles were obtained after only 2 h of milling time and were found to coexist with iron oxide particles for longer times of exposure to mechanochemical activation. The milled samples were then subjected to thermal annealing, in order to test the reversibility of the collapse of the hyperfine structure. The thermal annealing performed (700°C, 1 h) was partly successful in restoring the magnetic hyperfine structure of milled hexaferrite. Complementary information was obtained using transmission electron microscopy (TEM) and electron diffraction (ED).     

Conductometric behaviour of alkali metal halides in non-aqueous solvents containing crown-ethers

The conductometric behaviour of NaCl, KCl and RbCl in ethanol solutions, in the presence of dicyclohexyl-18-crown-6, and of KI in acetonitrile solutions, in the presence of 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6 and dicyclohexyl-18-crown-6, has been investigated. The analysis of data has been performed by means of the Fuoss-Onsager-Skinner equations and the results compared with the parameters of the same salts in pure solvents. The addition of crown-ether to the ethanol solutions gives rise to a greater decrease in conductivity for KCl and RbCl than for NaCl, so that the maximum difference in the Λ_o values which is 4.7 Λ unit in pure ethanol, decreases to 0.9 Λ unit. Also the association constant to ion pairs of the three salts which is appreciable in pure ethanol, decreases to zero when the crown-ether is added. In acetonitrile the difference in the Λ_o values for systems with and without crowns is small for 12-crown-4 (～2.9 Λ unit); it increases according to the complexity of the added crown (～21 Λ unit for the 15-crown-5, ～24 Λ unit for the 18-crown-6, ～ 30 Λ unit for the dicyclo- and dibenzo-18-crown-6). A small association constant value was found for the systms KI with 12-crown-4 and with 15-crown-5 in this solvent. The results of the above systems are discussed in terms of competitive interaction forces of the crown-ethers and the solvent molecules on the ionic species present in solution.