The Emi2 Protein of Saccharomyces cerevisiae is a Hexokinase Expressed under Glucose Limitation

Hexokinases catalyze glucose phosphorylation at the first step in glycolysis in eukaryotes. In the budding yeast Saccharomyces cerevisiae , three enzymes for glucose phosphorylation have long been known: Hxk1, Hxk2, and Glk1. In this study, we focus on Emi2, a previously uncharacterized hexokinase-like protein of S. cerevisiae . Our data show that the recombinant Emi2 protein (rEmi2), expressed in Escherichia coli , possesses glucose-phosphorylating activity in the presence of ATP and Mg ²⁺ . It was also found that rEmi2 phosphorylates not only glucose but also fructose, mannose and glucosamine in vitro . In addition, we examined changes in the level of endogenous Emi2 protein in S. cerevisiae in the presence or absence of glucose and a non-fermentable carbon source. We found that the expression of Emi2 protein is tightly suppressed during proliferation in high glucose, while it is strongly upregulated in response to glucose limitation and the presence of a non-fermentable carbon source. Our data suggest that the expression of the endogenous Emi2 protein in S. cerevisiae is regulated under the control of Hxk2 in response to glucose availability in the environment.     

Oxidation of doped europium in BaMgAl10O17 by annealing studied by x‐ray‐absorption fine‐structure measurements

Abstract— We studied the influence of annealing in air on doped europium in BaMgAl₁₀O₁₇ by performing x‐ray absorption fine‐structure measurements. We determined the oxidation of doped divalent europium by annealing in air at over 500°C. The interatomic distance between the europium and the surrounding oxygen atoms was compressed by oxidation. It also appears that the oxidation process of europium is determined by the diffusion of oxygen into BaMgAl₁₀O₁₇.     

Decreasing the number of test specimens by utilizing both fracture stress and fracture location for the estimation of Weibull parameter

In a bending load test for brittle materials, such as ceramics for spacecraft and aircraft, decreasing the number of test specimens required is a crucial problem. This paper discusses the effectiveness of using the information of both fracture stress and fracture location to decrease the number of specimens required to obtain the same precision as the Weibull estimator. The following results were obtained: It was found that by adding the fracture location information, the precision of the Weibull parameter estimation under the optimal design became 1.5–1.9 times better compared with the case of using only the fracture stresses. This means the number of samples necessary to attain the same precision becomes 1/1.5–1/1.9. Tables and figures which give information on the number of samples necessary to attain the required precision are given.     

Volumetric properties of mixtures of 1,4-dioxane and water at high pressures

Densities of aqueous of 1,4-dioxane have been measured at temperatures from 298 to 348 K and at pressures up to 40 MPa by a vibrating-tube method. Molar volumes obtained with an estimated uncertainty of ±0.2°,% are correlated with pressure by the Tait equation within the experimental uncertainty. Pressure and composition dependences of the excess molar volume, partial molar volume, and isothermal compressibility are determined and they are compared with those of other aqueous solutions.     

Acute myocardial infarction during pregnancy caused by coronary artery spasm

A 33-year-old pregnant woman suffered from acute anteroseptal myocardial infarction at the 19th gestational week. Despite periodic attacks of myocardial ischaemia after admission, the coronary arteriograms under the use of nitroglycerin were normal. Thereafter, she remained free from the ischaemic events with diltiazem hydrochloride and delivered a healthy baby. The coronary arteriography at puerperium also showed no organic narrowing. However, the provocative test with acetylcholine chloride caused severe spasm of the left anterior descending coronary artery. These findings strongly suggest that acute myocardial infarction in this pregnant woman was caused by coronary artery spasm.     

Is it possible to differentiate between choledochal cyst and congenital biliary atresia (type I cyst) by antenatal ultrasonography?

Both choledochal cyst and congenital biliary atresia (type I cyst) may share the same ultrasonographic pattern. We report 2 cases which were shown to have cystic structures on the upper abdomen by antenatal ultrasonography. The size of the choledochal cyst found at 24 weeks' gestation increased steadily as gestational age advanced. But the size of the cyst in congenital biliary atresia found at 29 weeks' gestation remained unchanged throughout the remaining pregnancy. Cyst enlargement, therefore, may suggest the possibility of a choledochal cyst.     

Forming mental models in learning operating procedures for terminalequipment

People faced with an unfamiliar product or service tend to fall back on mental models based on analogical relationships with familiar products or services. Two experiments on the analogical relationships or metaphors that people might use when operating a communications terminal are described. In the first experiment, the role previously acquired operating knowledge has in determining the mental models people use when directory dialing with novel equipment is examined. In a second experiment, it is shown that an explicit appeal to an analogy between conventional mail and electronic mail can help users learn to use an electronic mail system, and make it easier for them to remember how to use the system as long as 90 days after initial exposure. It is concluded that the mental model is constructed only from the user's operating knowledge acquired as a result of past experiences, and the metaphor method is effective when the instructions are metaphorically taught     

A 64-Mb DRAM with meshed power line

A 64-Mb dynamic RAM (DRAM) has been developed with a meshed power line (MPL) and a quasi-distributed sense-amplifier driver (qDSAD) scheme. It realizes high speed, t_RAS=50 ns (typical) at V_cc=3.3 V, and 16-b input/output (I/O). This MPL+qDSAD scheme can reduce sensing delay caused by the metal layer resistance. Furthermore, to suppress crosstalk noise, a V_SS shield peripheral layout scheme has been introduced, which also widens power line widths. This 64-Mb DRAM was fabricated with 0.4-μm CMOS technology using KrF excimer laser lithography. A newly developed memory cell structure, the tunnel-shaped stacked-capacitor cell (TSSC), was adapted to this 64-Mb DRAM