Adenosine triphosphatase ofAspergillus nidulans: Stimulation by aminoacids

Summary Ca²⁺-dependent ATPase ofAspergillus nidulans was found to be stimulated by aminoacids in vitro. Both histidine and arginine stimulated the enzyme more effectively than the aromatic aminoacids. Supplementation of the growth medium with basic or aromatic aminoacids increased the enzyme activity in vivo 2–6-fold. The enhanced activity observed in these cultures in vivo was not mediated through the synthesis of new isoenzyme, as observed in proteinenriched cultures, but appeared to be through the activation of enzyme activity.     

Genetic and neuroimaging studies of cholinergic-neurotrophic modulation of visual attention

Molecular genetics can provide complementary information to neuroimaging methods on the neural mechanisms of perception and cognition. We investigated the role of cholinergic and neurotrophic genes in the modulation of visual attention, as reflected in behavioral, ERP, and MRI measures. Three studies examined the influence of single nucleotide polymorphisms (SNPs) in a nicotinic cholinergic gene, CHRNA4, and a neurotrophic gene, APOE. An association was found between a CHRNA4 SNP and reaction time (RT) measures of orienting of visual attention in space. This behavioral finding was complemented by an association between the same SNP and ERP components reflecting early perceptual/attentional processing. In contrast to these relatively specific effects, the APOE e4 SNP had broad effects on cognition, including visual attention and working memory. An interaction was also found between APOE and CHRNA4 for white matter volume and RT measures of attentional efficiency. These studies confirm the role of nicotinic cholinergic innervation for visual attention and show the benefits of a “multi-level phenotyping” approach in the neurogenetics of attention.     

Neural mechanisms of unconscious visual motion priming

The neural correlates of the motion priming were examined in normal young subjects using event-related brain potentials (ERPs) and functional magnetic resonance imaging (fMRI). Visual motion perception can be uncon-sciously biased in favor of a particular direction by a pre-ceding motion in that direction. Motion priming first in-volved an enhancement of ERP amplitude about 100 ms fol-lowing the onset of motion. The amplitudes of ERP compo-nents after 350 ms were also increased. The fMRI results suggest that the early-latency effect reflects modulation of neural responses in extrastriate cortex. Higher-level visual processing areas, including cortical regions MT/MST and the intraparietal cortices were also activated. The findings provide direct evidence that unconscious priming of motion perception is the result of interaction of direction-selective neural responses to motion stimuli. The results cannot be accounted for by refractoriness of neural responses, but in-stead support a theory of motion priming based on motion opponency, as proposed in computational models.     

Platinum-supported mesoporous carbon (Pt/CMK-3) as anodic catalyst for direct methanol fuel cell applications: The effect of preparation and deposition methods

Platinum-supported ordered mesoporous carbon catalysts were prepared employing colloidal platinum reduced by four different reducing agents, viz., paraformaldehyde, sodium borohydride, ethylene glycol and hydrogen, and deposited over ordered mesoporous carbon (CMK-3) synthesized by silica hard template (SBA-15). The resulting platinum nanoparticles supported mesoporous carbon, designated as Pt/CMK-3, catalysts were tested for the electocatalytic oxidation of methanol. The effect of the various reduction methods on the influence of particle size vis- a-vis on the electrocatalytic effect is investigated. All the catalysts were systematically characterized by XRD, BET and TEM. The results of the synthetic methods, characterization techniques and the electrocatalytic performance indicate that the Pt/CMK-3 catalysts are superior to that prepared with activated carbon (Pt/AC) as well as with that of the commercial platinumsupported carbon catalyst (Pt/E-TEK). In particular, the catalyst, Pt/CMK-3, prepared using paraformaldehyde reduced platinum showed much higher activity and long-term stability as compared to the other reducing methods.     

Genetic and neuroimaging studies of cholinergic-neurotrophic modulation of visual attention

Molecular genetics can provide complementary information to neuroimaging methods on the neural mechanisms of perception and cognition. We investigated the role of cholinergic and neurotrophic genes in the modulation of visual attention, as reflected in behavioral, ERP, and MRI measures. Three studies examined the influence of single nucleotide polymorphisms (SNPs) in a nicotinic cholinergic gene, CHRNA4, and a neurotrophic gene, APOE. An association was found between a CHRNA4 SNP and reaction time (RT) measures of orienting of visual attention in space. This behavioral finding was complemented by an association between the same SNP and ERP components reflecting early perceptual/attentional processing. In contrast to these relatively specific effects, the APOE e4 SNP had broad effects on cognition, including visual attention and working memory. An interaction was also found between APOE and CHRNA4 for white matter volume and RT measures of attentional efficiency. These studies confirm the role of nicotinic cholinergic innervation for visual attention and show the benefits of a “multi-level phenotyping” approach in the neurogenetics of attention.     

Signatures of universal characteristics of fractal fluctuations in global mean monthly temperature anomalies

This paper proposes a general systems theory for fractals visualising the emergence of successively larger scale fluctuations resulting from the space-time integration of enclosed smaller scale fluctuations. Global gridded time series data sets of monthly mean temperatures for the period 1880–2007/2008 are analysed to show that data sets and corresponding power spectra exhibit distributions close to the model predicted inverse power law distribution. The model predicted and observed universal spectrum for interannual variability rules out linear secular trends in global monthly mean temperatures. Global warming results in intensification of fluctuations of all scales and manifested immediately in high frequency fluctuations.