The System HfO2-TiO2

The system HfO₂-TiO₂ was studied in the 0 to 50 mol% TiO₂ region using X-ray diffraction and thermal analysis. The monoclinic ( M ) ⇌ tetragonal ( T ) phase transition of HfO₂ was found at 1750°± 20°C. The definite compound HfTiO₄ melts incongruently at 1980°± 10°C, 53 mol% TiO₂. A metatectic at 2300°± 20°C, 35 mol% TiO₂ was observed. The eutectoid decomposition of HfO_2,ss) ( T ) → HfO_2,ss ( M ) + HfTiO_34,ssss occurred at 1570°± 20°C and 22.5 mol% TiO₂. The maximum solubility of TiO₂ in HfO_2,ss,( M ) is 10 mol% at 1570°± 20°C and in HfO_2,ss ( T ) is 30 mol% at 1980°± 10°C. On the HfO₂-rich side and in the 10 to 30 mol% TiO₂ range a second monoclinic phase M of HfO₂( M ) type was observed for samples cooled after a melting or an annealing above 1600°C. The phase relations of the complete phase diagram are given, using the data of Schevchenko et al. for the 50% to 100% TiO₂ region, which are based on thermal analysis techniques.     

Phase Diagram of a Nickel-Zinc Ferrite of Composition Ni0.685Zn0.177Fe2.138O4+γ

The oxygen content of Ni_0.685Zn_0.177Fe_2.138O_4+γ was determined gravimetrically at atmospheric pressure in varying Po₂ , 3.5 × 10⁻⁴ to 1.0 atm at 600° to 1450°C. The phase boundary associated with the precipitation of α-Fe₂O₃ was determined from the change in slope of γ vs T plots observed on heating. Metastability is particularly evident for curves observed on cooling. Isacompositional lines (0.002 < γ < 0.045) are shown on a plot of log PO₂ vs 1/T. An enthalpy of -21.6 kcal/mol is calculated for the oxidation of Fe²⁺.     

Cloning of the Multicopy Suppressor Gene SUR7: Evidence for a Functional Relationship between the Yeast Actin-binding Protein Rvs167 and a Putative Membranous Protein

The rvs161 and rvs167 mutant cells exhibit several identical phenotypes including sensitivity to several different growth conditions and morphological defects such as alteration of the actin cytoskeleton and budding patterns. The selection of genes that, when overexpressed, are able to suppress the reduced viability upon carbon starvation of the rvs167 mutant strain, has allowed the cloning of the SUR7 gene (Accession Number Z46729x11). We showed that the suppressive ability of the overexpressed SUR7 gene concerns all the rvs167 phenotypes. However, this suppression is only partial since the rvs167-suppressed strain is not of wild-type phenotype. Moreover, SUR7 is also able to suppress partially the phenotypes exhibited by the rvs161 and rvs167 rvs161 mutant strains. The SUR7 gene encodes a putative integral membrane protein with four transmembrane domains. Furthermore, sequence comparisons revealed that Sur7p and two other proteins, Ynl194p and Ydl222p, present significant sequence and structural similarities. Taken together, these results strongly suggest that the Rvs161 and Rvs167 proteins act together in relation with Sur7p. Moreover, the putative transmembranous character of Sur7p suggests a membrane localization of the Rvs function, a localization which is consistent with the different rvs phenotypes and the actin–Rvs167p interaction. © 1997 John Wiley & Sons, Ltd.     

RECENT DEVELOPMENTS IN SHAPE SENSITIVITY ANALYSIS: THE PHYSICAL APPROACH

Because of increasing CAD requirements in industry, shape optimum design by finite element is an important field of research and development. The global solution of this problem involves two main aspects: the first one is the availability of powerful and robust optimizers and the second one is the necessity of producing the best sensitivity analysis for the approximate problem concerned by optimization. Nowadays, several good softwares or computer programs are available in order to solve a well stated approximate optimization problem. For sensitivity analysis the method using big design elements is quite successful but it appears that more general and powerful methods could be implemented. It is expected that the physical approach developed in this paper could be one of these better methods of the future.     

VIRULENCE LEVELS OF BIOFILM-GROWN LISTERIA MONOCYTOGENES LO28 ARE LOWER THAN THOSE OF PLANKTONIC CELLS IN AN ORAL INOCULATION TEST ON MICE

The aim of this study was to produce Listeria monocytogenes biofilms suitable for virulence assays and to determine whether the released bacteria had the same virulence potential as their planktonic counterparts. Biofilms of Listeria monocytogenes LO28 strain, with or without Sphingomonas paucimobilis CCL10 strain, containing up to 7 log₁₀ cfu/cm² were produced in polypropylene syringes. The virulence of strain LO28 was analyzed in mice after intravenous, subcutaneous and oral inoculation. Its virulence level in binary cultures was not significantly different from that of monocultures. L. monocytogenes LO28 virulence in biofilms was lower than that of their planktonic counterparts after oral inoculation. Our results suggest that biofilms pose no greater health risk to the consumer than planktonic bacteria.     

On some models for developmental systems Part VIII. Systems with and without feedback: structural properties

In developmental systems without feedback, the growth is polynomial and a hierarchy exists between subsystems according to the location of the generating subword along the generating word; as a consequence, the possibility of regeneration after partial destruction is limited and relative stability of the system structure is observed if one letter is changed in the generating word. In developmental systems whose generating word has feedback the growth is exponential, regeneration may be complete following the survival of a unique element and changing one letter in the generating word may cause a complete change in the structure of the system.     

Gelation of Aluminum Hydroxide Sols

The gelation of aluminum hydroxide sols obtained from aluminum sec -butoxide has been studied as a function of the conditions of preparation, including pH, temperature, and time of aging. The preceding studies of Yoldas have been extended in more acidic conditions, up to a molar proportion of 1.12 HNO₃ per Al(OC₄H₉)₃. It has been found that stable sols can easily be obtained by processing at any temperature between 20° and 90°C beyond a molar proportion of 0.28 HNO₃. The corresponding gels are suggested to have a boehmite-like structure in which there is a metastable folding of the (020) layers at 20°C, and a stable unfolding at 80°C, the two structures coexisting at intermediate processing temperatures.     

Adaptive limits for pc-based inventory control

The paper reports work on the development of a decision support system to implement the adaptive control limits approach within a transaction-oriented pc-based inventory control system. The system developed offers ways for an automatic adjustment of the inventory control parameters when the sales forecasts are updated or management adjusts its expected customer service level. Technical aspects of the approach used to generate the adaptive limits are presented along with an illustrative case example of its application.