Actual new cancer-causing hydrazines, hydrazides, and hydrazones

Twenty actual new cancer-causing hydrazines, hydrazides, and hydrazones of synthetic or natural origin are described. These compounds induce tumors in various target tissues in mice, hamsters and rats. To nine of these compounds the human population is exposed in the form of drugs, agricultural herbicides, and naturally occurring ingredients of edible mushrooms. Yet, with one exception, none of the hydrazines described here were investigated for cancer-inducing abilities in man. The human population should be warned against the use of this hazardous class of chemicals, the total number of which is now 40.     

Mechanical Resuscitation of Chemical Oscillations in Belousov–Zhabotinsky Gels

The conversion of mechanical to chemical energy is a natural phenomenon that few synthetic materials have been able to mimic robustly. The first demonstration of mechanical triggering of Belousov–Zhabotinsky (BZ) oscillations is presented in N‐isopropylacrylamide‐co‐Ru(bpy)₃ gels for which the oscillatory nature of the BZ reaction can be visualized via periodic changes in color. It is demonstrated that BZ oscillations can be induced by the application of compressive stress to gels in which the BZ reaction has attained a steady‐state upon depletion of reagents. Such macroscopic compression physically increases the volume fraction of polymer to which the Ru(bpy)₃ catalyst is grafted and triggers BZ oscillations by utilizing unreacted reagents in the aqueous solution, thus effectively resuscitating and extending the functionality of these oscillatory gels. The applied stress and the initial concentrations of malonic acid are varied to show that there is a critical stress required to trigger and restore these oscillations, and that the period and amplitude of oscillation are tunable. Leveraging this capacity to restore the functionality of the material via applied pressure, sensor applications comprising discrete BZ gels, which are capable of both visually indicating the origin of mechanical loading and transmitting this signal away from the deformation site, are demonstrated. Mechanical resuscitation of such chemical oscillations affords novel approaches to creating pressure sensors based on self‐oscillating gels.     

Crops that feed the world 8: Potato: are the trends of increased global production sustainable?

Potato is produced on all continents except Antarctica and is the world??s third most important food crop. Potato production has increased dramatically in developing countries in the past two decades, and has now overtaken that in the developed world, underlining the growing importance of potato as a staple food crop to meet the demands of increasing human populations. Potato is also an important source of starch. It has been adapted for cultivation in a wide range of environments and, with the availability of significant germplasm resources, the potential to further exploit its natural biodiversity is considerable. Potato yields vary considerably across the world, with the lowest being in Sub-Saharan Africa; <75?% of the global average and <30?% of the top producing regions. Many factors contribute to this variation, providing targets for improved agronomic practice and a stimulus to improve varieties to increase production in the poorest-yielding countries. The ability to adapt potato to withstand multiple biotic and abiotic stresses is critical to its future growth as a major food source. In current breeding efforts, strong emphasis is being placed on these traits in attempts to better equip the potato crop in a changing climate. The genomics era is accelerating our understanding of the key genes and mechanisms underlying potato development, physiology, water and nutrient use efficiency and resistance to biotic and abiotic stresses. Genomics technologies provide the potential for more rapid, marker-assisted breeding strategies, and afford the opportunity for biotechnological approaches, particularly in the case of major gene resistance to pests and diseases. Continued review of GM policies and regulations, and associated social and political opinions, are needed to guide and determine the safest and most productive routes to potato improvement.     

Dissolution and Migration of Platinum in PEMFCs Investigated for Start/Stop Cycling and High Potential Degradation

Dissolution and migration of platinum due to start/stop degradation and increased cathode potentials were studied for commercial membrane electrode assemblies (MEA). The chosen conditions closely mimic real situations in automotive operation. In start/stop tests, we observed a strongly enhanced platinum dissolution due to the dynamic interplay of repeated cell start‐up and consecutive normal fuel cell operation, which is related to platinum oxidation (start‐up) and reduction (normal operation) cycles. Consequently, the performed test protocols distinguish between dynamic and static load profiles. Electrochemical investigations before and after degradation monitor the loss in cell performance. Since electron microscopy offers the unique possibility to unravel and distinguish degradation due to carbon corrosion and agglomeration or platinum dissolution, a focus was set on this method. For the start/stop MEA pronounced platinum dissolution accompanied by the formation of large platinum precipitations in the membrane was found. Carbon corrosion was also observed, but did not lead to a significantly reduced porosity and loss in platinum dispersion. In contrast, the MEA which was exposed to high constant potentials exhibited severe damage to the 3D cathode structure due to carbon corrosion. However, no pronounced platinum dissolution was observed and only few Pt precipitations were found in the membrane itself.     

Aging and recollection in the accuracy of judgments of learning.

Dual-process theories propose that episodic memory performance reflects both recollection of prior details as well as more automatic influences of the past. The authors explored the idea that recollection mediates the accuracy of judgments of learning (JOLs) and may also help explain age differences in JOL accuracy. Young and older adults made immediate JOLs at study and then completed recognition or recall tests that included a recollect/familiar judgment. JOLs were found to be strongly related to recollected items but not to items remembered on the basis of familiarity. The pattern was weaker in older adults, consistent with age-related declines in recollection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simplified Model of Voids Able to Mimic Accelerating Expansion at High <Emphasis Type="Italic">z</Emphasis> without Dark Energy

We present a simplified model of voids in the Universe. Using this model, we investigate the effect of inhomogeneities on light propagation. We calculate the corresponding Hubble diagrams and compare them to those expected in different cosmological models. We find that voids in a universe containing only nonrelativistic matter can mimic accelerating expansion as far as Hubble diagrams are concerned.