A hemispheric division of labor aids mental rotation.

In the present study, we investigated whether a hemispheric division of labor is most advantageous to performance when lateralized inputs place unequal resource demands on the left and right cerebral hemispheres. In each trial, participants decided whether 2 rotated letters, presented either in the same visual field (within-field trials) or in opposite visual fields (across-field trials), were both of normal orientation, or whether one was normal and the other was mirror-reversed. To discriminate a letter's orientation, one must rotate the letter to the upright position. Therefore, we manipulated whether the two letters imposed similar or dissimilar demands on cognitive resources by varying the number of degrees that each letter needed to be rotated to reach the upright position. As predicted, in 2 experiments we found that the across-field advantage increased as the number of degrees each letter needed to be rotated became more dissimilar. These findings support a current model of hemispheric interactions, which posits that an unequal hemispheric distribution of cognitive load allows the cerebral hemispheres to take the lead for different aspects of cognitive processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Generalized Technique for Register Counting and its Application to Cost-Optimal DSP Architecture Synthesis

In this paper we propose a generalized technique to count the required number of registers in a schedule which supports overlapped scheduling and can be applied to the case where a general digit-serial data format is used. This technique is integrated into an integer linear programming (ILP) model for time-constrained scheduling. In the ILP model, appropriate processors of certain data formats are chosen from a library of processors and data format converters are automatically inserted between processors of different data formats if necessary. Then the required number of registers for each data format is evaluated correctly by the proposed technique. Hence an optimal architecture for a given digital signal processing algorithm is synthesized where the cost of registers as well as the cost of processors and data format converters are minimized. It is shown that by including the cost of registers in the synthesis task as proposed in this paper leads to up to 12.8% savings in the total cost of the synthesized architecture when compared with synthesis performed without including the register cost in the total cost.     

An absolute requirement of fructose 1,6-bisphosphate for the Lactobacillus caseiL-lactate dehydrogenase activity induced by a single amino acid substitution

Lactobacillus casei allosteric L-lactate dehydrogenase (L-LDH)absolutely requires fructose 1,6-bisphosphate [Fru(1,6)P2] forits catalytic activity under neutral conditions, but exhibitsmarked catalytic activity in the absence of Fru(1,6)P₂ underacidic conditions through the homotropic activation effect ofsubstrate pyruvate. In this enzyme, a single amino acid replacement,i.e. that of His205 conserved in the Fru(1,6)P₂-binding siteof certain allosteric L-LDHs of lactic acid bacteria with Thr,did not induce a marked loss of the activation effect of Fru(1,6)P₂or divalent metal ions, which are potent activators that improvethe activation function of Fru(1,6)P₂ under neutral conditions.However, this replacement induced a great loss of the Fru(1,6)P₂-independentactivation effect of pyruvate or pyruvate analogs under acidicconditions, consequently indicating an absolute Fru(1,6)P₂ requirementfor the enzyme activity. The replacement also induced a significantreduction in the pH-dependent sensitivity of the enzyme to Fru(1,6)P₂,through a slight decrease and increase of the Fru(1,6)P₂ sensitivityunder acidic and neutral conditions, respectively, indicatingthat His205 is also largely involved in the pH-dependent sensitivityof L.casei L-LDH to Fru(1,6)P₂. The role of His205 in the allostericregulation of the enzyme is discussed on the basis of the knowncrystal structures of L-LDHs.     

Sustained photobiological hydrogen production in the presence of N2 by nitrogenase mutants of the heterocyst-forming cyanobacterium Anabaena

Heterocyst-forming cells of the cyanobacterium Anabaena sp. strain PCC 7120 ΔHup, lacking an uptake hydrogenase, photobiologically produce H₂ by nitrogenase. Under N₂-rich atmosphere, the nitrogenase activity declines in a rather short time due to the sufficiency of combined nitrogen. From the parental ΔHup strain, site-directed double-crossover variants, dc-Q193S and dc-R284H, were created with amino acid substitutions presumed to be located in the vicinity of the FeMo-cofactor of nitrogenase. Unlike the case for the ΔHup strain, H₂ production activities of the variants were not decreased by the presence of high concentrations of N₂ and they continuously produced H₂ over 21 days with occasional headspace gas replacement. This property of N₂ insensitivity is a potentially useful strategy for reducing the cost of the culture gas in future practical applications of sustainable biofuel production. This Anabaena strain has only the Mo-containing nitrogenase which reduces acetylene to ethylene, but the dc-Q193S variant also produced ethane at low but measurable rates along with greater rates of ethylene production.     

Effects of fatty acid and emulsifier on the complex formation and in vitro digestibility of gelatinized potato starch

The effects of fatty acid, monoacylglycerol, and polyglycerol fatty acid ester with varying chain length in their acyl chains on the extent of complex formation (complex index) and in vitro enzymatic digestibility of gelatinized potato starch were investigated. The complex index increased with increase in the concentration of the ligands (fatty acid, monoacylglycerol, and polyglycerol fatty acid ester), with the plateau in the complex index value depending on the type of ligands. In comparison of complex index among fatty acid-samples, the complex index maximum increased as the chain length increased up to octanoic acid and then decreased. In comparison of complex index among fatty acid-, monoacylglycerol-, and polyglycerol fatty acid ester-samples at each acyl chain, the complex index maximum followed the order polyglycerol fatty acid ester > monoacylglycerol > fatty acid. Fatty acid, monoacylglycerol, and polyglycerol fatty acid ester with long acyl chains greatly reduced the enzymatic hydrolysis of starch. Polyglycerol fatty acid ester with palmitic acid chains was the strongest inhibitor of starch hydrolysis, suggesting that further complex formation may occur during the hydrolysis of gelatinized starch (enzyme-annealing).     

Liquid phase growth of graphene on silicon carbide

We developed a novel method to produce graphene on silicon carbide (SiC) at a temperature as low as 1000 °C. The method is based on liquid phase growth (LPG) of graphene mediated by liquid gallium, which acts not only as a flux to store carbon dissolved from a surface of SiC when heated, but also as a catalyst to promote the formation of graphene on SiC when cooled. Our experimental results revealed that gallium-treated SiC substrates are coated with uniform and continuous graphene films. The LPG method is able to supply graphene films consisting of one to several hundreds of layers, depending on heating temperatures. Our approach can not only provide an alternative way to form graphene natively on SiC, but will also bring a technological breakthrough in industrial applications of graphene, e.g. the realization of graphene-on-insulator substrates.     

Cloning and characterization of a β-N-acetylglucosaminidase (BmFDL) from silkworm Bombyx mori

In insects, β-N-acetylglucosaminidase (GlcNAcase) participates in critical physiological processes such as fertilization, metamorphosis, and glycoconjugate degradation. Insects produce glycoproteins carrying paucimannosidic-type N-glycans, the terminal GlcNAc residue of which is cleaved by a GlcNAc-linkage specific GlcNAcase, also known as the fused lobes (FDL) protein. To obtain information on the structure of GlcNAcases and insight into their contribution to physiological processes, we cloned Bombyx mori FDL (BmFDL) from silkworm larvae. The full-length cDNA (1.9 kb) encoded a protein of 633 amino acids with 42% amino acid sequence identity to Drosophila melanogaster FDL (DmFDL). Recombinant BmFDL cleaved only β-1,2-linked GlcNAc residues from the α-1,3 branch of biantennary N-glycan. This substrate specificity was similar to that of DmFDL. Microsomal FDL activity was inhibited by anti-BmFDL antibodies. Taken together, our results suggest that BmFDL is a N-glycan-processing GlcNAcase in B. mori.     

A flow method with photocatalytic oxidation of dissolved organic matter using a solid-phase (TiO2) reactor followed by amperometric detection of consumed oxygen

A photocatalytic sensor for the determination of chemical oxygen demand (COD) using titanium dioxide, based on the use of a pair of oxygen electrodes and flow injection analysis, is described. The measuring principle is based on the direct determination of the oxygen concentration change resulting from photocataltic oxidation of organic compounds. One of the two oxygen electrodes, the reference oxygen electrode, was utilized to measure the reference signal responding only to oxygen present in the injected samples. Oxygen consumption due to the TiO2-catalyzed photochemical oxidation of organic compounds in samples was monitored with the working oxygen electrode. The COD value of this sensor was calculated as the difference of the currents at reference and working oxygen electrodes, respectively. The operation characteristics of the sensor are demonstrated using artificially treated wastewater as a substrate. The sensor was also applied to the determination of COD in real water samples from dam reservoirs (n = 20) all over Japan. The results were in good agreement with those from the conventional COD methods (i.e., permanganate and dichromate methods).     

Determining the minimum iteration period of an algorithm

Digital signal processing algorithms are repetitive in nature. These algorithms are described by iterative data-flow graphs where nodes represent computations and edges represent communications. For all data-flow graphs, there exists a fundamental lower bound on the iteration period referred to as theiteration bound. Determining the iteration bound for signal processing algorithms described by iterative data-flow graphs is an important problem. In this paper we review two existing algorithms for determination of the iteration bound. Then we propose another novel method based on theminimum cycle mean algorithm to determine the iteration bound with a lower polynomial time complexity than the two existing techniques. It is convenient to represent many multi-rate signal processing algorithms by multi-rate data-flow graphs. The iteration bound of a multi-rate data-flow graph (MRDFG) can be determined by considering the single-rate data-flow graph (SRDFG) equivalent of the MRDFG. However, the equivalent single-rate data-flow graph contains many redundant nodes and edges. The iteration bound of the MRDFG can be determined faster if these redundancies in the equivalent SRDFG are first removed. A previous approach has considered elimination of edge redundancy. In this paper we present an approach to eliminatenode redundancy in the MRDFG. We combine elimination of node and edge redundancies to propose a novel algorithm for faster determination of the iteration bound of the MRDFG.This research was supported by the Advanced Research Projects Agency and monitored by Wright—Patterson AFB under contract number F33615-93-C-1309.