Defect theorems with compatibility relations

We consider words together with a compatibility relation induced by a relation on letters. Unique factorization with respect to two arbitrary word relations R and S defines the (R,S)-freeness of the semigroup considered. We generalize the stability theorem of Schützenberger and Tilson’s closure result for (R,S)-free semigroups. The inner and the outer (R,S)-unique factorization hull and the (R,S)-free hull of a set of words are introduced and we show how they can be computed. We prove that the (R,S)-unique factorization hulls possess a defect effect, which implies a variant of a cumulative defect theorem of word semigroups. In addition, a defect theorem of partial words is proved as a corollary.     

Optimization of ultrasound-assisted extraction (UAE) of flavonoids compounds (FC) from hawthorn seed (HS)

Hawthorn seed (HS), an important by-product of the Hawthorn industry, is rich in potentially health-promoting flavonoids compounds. In this paper, the ultrasound-assisted extraction (UAE) of FC from HS was investigated. Important variables and their levels were obtained using Plackett-Burman (PB) design and Box-Behnken (BB) design. A mathematical model was developed to show the effects of each variable and their combinatorial interactions on extraction yield of FC. A high coefficient of determination (R² = 91.26%) indicated good agreement between the experimental and predicted values of FC yield. The optimum levels of these significant parameters were determined using response surface methodology (RSM), which revealed these as follows: ultrasound temperature 65 °C, ultrasonic time 37 min, extraction temperature 91 °C, extraction time 1.5 h, solid-liquid ratio of 1:18, and 72% ethanol. Under the optimum condition, the UAE rate of FC was up to 91.7%, and the yield of FC was 16.45 ± 0.02 mg/g (P < 0.05) that was 1.32-fold the yield of conventional reflux extraction (CRE).     

Determination of α-decay branching ratios for 178, 179Hg

The neutron-deficient nuclides ^{182, 183}Pb were produced at the Accelerator Laboratory of the University of Jyv?skyl? by bombarding a ¹⁰⁷Ag target with ⁷⁸Kr ions. The nuclei of interest were separated using the RITU gas-filled separator and their radioactive decays investigated using the GREAT spectrometer. Correlating the $ \alpha$ decays of these Pb isotopes with those of their respective Hg daughters allowed $ \alpha$ -decay branching ratios of $\ensuremath b_\alpha($ ^178Hg) = 89(4)% and $\ensuremath b_\alpha($ ^179Hg) = 75(4)% to be deduced.     

Perceptually informed synthesis of bandlimited classical waveforms using integrated polynomial interpolation

Digital subtractive synthesis is a popular music synthesis method, which requires oscillators that are aliasing-free in a perceptual sense. It is a research challenge to find computationally efficient waveform generation algorithms that produce similar-sounding signals to analog music synthesizers but which are free from audible aliasing. A technique for approximately bandlimited waveform generation is considered that is based on a polynomial correction function, which is defined as the difference of a non-bandlimited step function and a polynomial approximation of the ideal bandlimited step function. It is shown that the ideal bandlimited step function is equivalent to the sine integral, and that integrated polynomial interpolation methods can successfully approximate it. Integrated Lagrange interpolation and B-spline basis functions are considered for polynomial approximation. The polynomial correction function can be added onto samples around each discontinuity in a non-bandlimited waveform to suppress aliasing. Comparison against previously known methods shows that the proposed technique yields the best tradeoff between computational cost and sound quality. The superior method amongst those considered in this study is the integrated third-order B-spline correction function, which offers perceptually aliasing-free sawtooth emulation up to the fundamental frequency of 7.8 kHz at the sample rate of 44.1 kHz.     

Binding properties of HABA-type azo derivatives to avidin and avidin-related protein 4

The chicken genome encodes several biotin-binding proteins, including avidin and avidin-related protein 4 (AVR4). In addition to D-biotin, avidin binds an azo dye compound, 4-hydroxyazobenzene-2-carboxylic acid (HABA), but the HABA-binding properties of AVR4 are not yet known. Differential scanning calorimetry, UV/visible spectroscopy, and molecular modeling were used to analyze the binding of 15 azo molecules to avidin and AVR4. Significant differences are seen in azo compound preferences for the two proteins, emphasizing the importance of the loop between strands beta3 and beta4 for azo ligand recognition; information on these loops is provided by the high-resolution (1.5 A) X-ray structure for avidin reported here. These results may be valuable in designing improved tools for avidin-based life science and nanobiotechnology applications.     

Evidence for non-yrast states in 254No

Evidence for the decay of non-yrast states in ²⁵⁴No has been observed for the first time in an experiment performed at the University of Jyv?skyl?. The experiment employed the JUROGAM array of germanium detectors coupled to the gas-filled recoil separator RITU and the focal-plane spectrometer GREAT. The ground-state rotational band has been tentatively extended up to a spin of 24ℏ and has a smoothly behaving dynamical moment of inertia. It is speculated that the observation of high-energy γ-rays is due to the decay of a K = 3 band-head state.     

An expedient synthesis of spiroketals: model studies for the calyculin C16-C25 fragment

A new short strategy to prepare the spiroketal fragment of calyculins is presented. A novel Seyferth-Gilbert type homologation of hindered lactols to the corresponding alkynes has been achieved for the first time. The spirocyclization was achieved efficiently via a DIHMA (double intramolecular hetero-Michael addition) process of this hindered ynone. The spirocyclization rate is not dependent on the stereochemistry of the alkoxy substituent in the oxolane ring.     

Quantitative estimation of brain white matter abnormalities in elderly subjects using magnetic resonance imaging

Twenty-five elderly subjects were examined with brain magnetic resonance imaging (MRI). The subjects were divided into two groups: those with Mini-Mental State Examination (MMSE) scores above 25, and those subjects with MMSE scores between 18 and 24. The degree of white matter abnormalities (WMA) (expressed as relative volumes) as well as the presence of cerebrovascular risk factors were evaluated in the two groups. We found that a) subjects with low MMSE scores had significantly larger relative volumes of WMA than the subjects with higher scores, b) a significant correlation (r_s = 0.53, p < 0.009) between MMSE scores and the relative volume of WMA was also established, and c) a weak significant correlation (r_s = −0.51, p < 0.05) between arterial blood pressure and WMA was found in the subjects with high MMSE scores. Besides these findings no other correlations between the presence of cerebrovascular risk factors and WMA were found in any of the groups.     

Squares,clique graphs,and chordality

We study the squares and the clique graphs of chordal graphs and various special classes of chordal graphs. Chordality conditions for squares and clique graphs are given. Several theorems concering chordal graphs are generalized. © 1996 John Wiley & Sons, Inc.