Constitution of Bone China: I, High-Temperature Phase Equilibrium Studies in the System Tricalcium Phosphate—Alumina—Silica

This investigation represents a first attempt to interpret the thermal behavior and constitution of bone china by means of a phase diagram of an idealized system. A consideration of the Tricalcium phosphate-alumina-sica phase diagram in relation to the quaternary system lime-alumina-phosphorus pentoxide-silica indicates that the composition of a normally tired commercial bone china body is β-tricalcium phosphate and anorthite in a siliceous glassy matrix. X-ray examinations of many such bodies confirm this interpretation. This preliminary investigation indicates the most profitable fields for further research.     

Momentum and Heat Transfer in Gas Atomization of Melts

Gas atomization of melt is widely used to produce metal powders and spray formed parts. In this process heat and momentum transfer of metal droplets take place during their flight in the gas medium. It is quite important to know the values of various parameters related to these two modes of transport phenomena. In the present paper mathematical models were developed and experimentally verified to predict values of various parameters, such as droplet and gas velocity, droplet temperature with time and distance travelled, percentage release of latent heat by the droplet. Four metals, lead, zinc, aluminium and tin were atomized to collect experimental data.     

THE EPISTEMOLOGY OF THE GENERAL SYSTEMS PROBLEM SOLVER

Abstract

In this paper, I draw a connection between the so-called classical definition of knowledge and the epistemological framework underlying George J. Klir's General Systems Problem Solver methodology. More specifically, I suggest that it is very close to the Representational Realism articulated by such early empiricists as John Locke. However, I also point out that the GSPS epistemology has an affinity to the so-called constructivist view of knowledge, one that t argue is not compatible with Representational Realism     

Transient evoked otoacoustic emissions in patients with normal hearing and in patients with hearing loss

OBJECTIVES: 1) To evaluate transient evoked otoacoustic emission (TEOAE) test performance when measurements are made under routine clinical conditions. 2) To evaluate TEOAE test performance as a function of frequency and as a function of the magnitude of hearing loss. 3) To compare test performance using univariate and multivariate approaches to data analyses. 4) To provide a means of interpreting clinical TEOAE measurements. DESIGN: TEOAEs were measured in 452 ears of 246 patients. All measurements were made after acoustic immittance assessments, which were used to demonstrate that middle-ear function was normal at the time of the TEOAE test. TEOAE amplitudes and signal to noise ratios (SNRs), analyzed into octave bands centered at 1, 2, and 4 kHz, were compared with the pure-tone threshold at the same frequencies. Data were analyzed with clinical decision theory, cumulative distributions, discriminant analyses, and logistic regressions. RESULTS: Using univariate analysis techniques, TEOAEs accurately identified auditory status at 2 and 4 kHz but were less accurate at 1 kHz. Test performance was best when audiometric thresholds between 20 and 30 dB HL were used as the criteria for normal hearing. TEOAE SNR resulted in better test performance than did TEOAE amplitude alone; this effect decreased as frequency increased. Multivariate analysis methods resulted in better separation between normal and impaired ears than did univariate approaches, which relied on only TEOAE amplitude or SNR when test frequency band and audiometric frequency were the same. This improvement in test performance was greatest at 1 kHz, decreased as frequency increased, and was negligible at 4 kHz. CONCLUSIONS: TEOAEs can be used to identify hearing loss in children under routine clinical conditions. Univariate tests accurately identified auditory status at mid and high frequencies but performed more poorly at lower frequencies. The decrease in performance as frequency decreases may be a result of increased noise at lower frequencies but also may be due to properties of the measurement paradigm ("QuickScreen," high-pass filter at 0.8 kHz), which would not be ideal for recording energy around 1 kHz. The improvement in test performance when SNR was used and the interaction of this effect with frequency, however, would be consistent with the view that test performance in lower frequencies is at least partially influenced by the level of background noise. Multivariate analysis techniques improved test performance compared with the more traditional univariate approaches to data analysis. An approach is provided that allows one to assign measured TEOAE amplitudes, SNRs, or outputs from multivariate analyses to one of three categories: response properties consistent with normal hearing; results consistent with hearing loss; hearing status undetermined.     

Identification and partial purification of human double strand RNase activity. A novel terminating mechanism for oligoribonucleotide antisense drugs

We have identified a double strand RNase (dsRNase) activity that can serve as a novel mechanism for chimeric antisense oligonucleotides comprised of 2'-methoxy 5' and 3' "wings" on either side of an oligoribonucleotide gap. Antisense molecules targeted to the point mutation in codon 12 of Harvey Ras (Ha-Ras) mRNA resulted in a dose-dependent reduction in Ha-Ras RNA. Reduction in Ha-Ras RNA was dependent on the oligoribonucleotide gap size with the minimum gap size being four nucleotides. An antisense oligonucleotide of the same composition, but containing four mismatches, was inactive. When chimeric antisense oligonucleotides were prehybridized with 17-mer oligoribonucleotides, extracts prepared from T24 cells, cytosol, and nuclei resulted in cleavage in the oligoribonucleotide gap. Both strands were cleaved. Neither mammalian nor Escherichia coli RNase HI cleaved the duplex, nor did single strand nucleases. The dsRNase activity resulted in cleavage products with 5'-phosphate and 3'-hydroxyl termini. Partial purification of dsRNase from rat liver cytosolic and nuclear fractions was effected. The cytosolic enzyme was purified approximately 165-fold. It has an approximate molecular weight of 50,000-65,000, a pH optimum of approximately 7.0, requires divalent cations, and is inactivated by approximately 300 mM NaCl. It is inactivated by heat, proteinase K, and also by a number of detergents and several organic solvents.     

Prediction of myocardial viability: Tl-201 versus sestamibi versus teboroxime compared with FDG uptake

Several radionuclide imaging agents have been used for assessing the presence of myocardial viability. These include Tl-201 chloride, Tc-99m sestamibi, and Tc-99m teboroxime. Currently, the most reliable indicator is F-18 FDG, which accumulates in severely hypoperfused myocardium, indicating preserved metabolic activity. The presence of chronically ischemic myocardium that has preserved metabolic activity is referred to as "hibernating" myocardium. In this series, the ability of Tl-201, sestamibi, and teboroxime to establish the existence of viable myocardium was compared with that of F-18 FDG. Seventy-seven patients with ischemic cardiomyopathy were referred for determination of myocardial viability. FDG images were compared with representative resting blood-flow images obtained from either: 1) 24 hour Tl-201 reinjection-redistribution images, 2) resting sestamibi blood-flow images, or 3) early images from resting teboroxime washout analysis. Tl-201 was found to underestimate myocardial viability in 41% of patients, Tc-99m sestamibi underestimated viability in 38% of patients, and Tc-99m teboroxime underestimated viability in 26% of patients. There was no significant difference in the prediction of viable myocardium among the three radiopharmaceuticals, as all three underestimated myocardial viability.     

Design of sampled-data control for multiple-time delayed generalised neural networks based on delay-partitioning approach

In this paper, we addressed the problem of stability analysis for a class of generalised mixed delayed neural networks by delay-partitioning approach. A novel integral inequality is developed by employing Wirtinger's integral inequality and Leibniz–Newton formula. By constructing an augmented Lyapunov–Krasovskii functional with triple and quadruple integral terms and using some standard integral inequality techniques, asymptotic stability criterion is obtained to the concerned neural networks. By converting the sampling period into a bounded time-varying delays, the error dynamics of the considered generalised neural networks are derived in terms of a dynamic system with sampling. Finally, numerical examples are given to show that the proposed method is less conservative than existing ones.