A threshold heating rate for single-stage heat treatments in glass-ceramics containing seed formers

The development of glass-ceramic materials is often achieved using an elementary microstructural strategy that splits the tasks of seed formation and functionality between two types of crystals. This strategy requires customized time-temperature ceramization protocols, which have been so far implemented using empirical parameters. Here, a more fundamental approach is proposed: the extent of overlap Oe between seed formation and volume crystallization is evaluated by calorimetric and dilatometric measurements, targeting the computation of a threshold heating rate qt for effective single-stage heat treatments. The applicability of this novel parameter is tested in TiO2-doped lithium magnesium aluminosilicate glass-ceramics, whose seed formation stage is thoroughly characterized by Raman spectroscopy and STEM. High-temperature X-ray diffraction demonstrates that insufficient seeding results in potentially weaker performances of the final products, due to large sizes and silica deficiency of the functional quartz solid solution crystals

The experimental gas-phase structures of 1,3,5-trisilylbenzene and hexasilylbenzene and the theoretical structures of all benzenes with three or more silyl substituents

The structures of 1,3,5-trisilylbenzene and hexasilylbenzene in the gas phase have been determined by electron diffraction, and that of 1,3,5-trisilylbenzene by X-ray crystallography. The structures of three trisilylbenzene isomers, three tetrasilylbenzenes, pentasilylbenzene and hexasilylbenzene have been computed, ab initio and using Density Functional Theory, at levels up to MP2/6-31G*. The primary effect of silyl substituents is to narrow the ring angle at the substituted carbon atoms. Steric interactions between silyl groups on neighbouring carbon atoms lead first to displacement of these groups away from one another, and then to displacement out of the ring plane, with alternate groups moving to opposite sides of the ring. In the extreme example, hexasilylbenzene, the SiCCSi dihedral angle is 17.8(8)°

Callimachi Cyrenaei hymni (cum suis scholiis Graecis) et Epigrammata. Ejusdem Poematium De coma Berenices, a Catullo versum. Nicodemi Frischlini Balingensis interpretationes duae Hymnorum : una oratione soluta : altera, carmine. Ejusdem interpretatio Epigrammatum et annotationes in Hymnos. Henrici Stephani partim emendationes partim annotationes in quosdam Hymnorum locos. Ejusdem duplex interpretatio Hymni primi, carmine utraque : quarum una, adstrictae, altera, liberae et paraphrasticae interpretationis exemplum esse possit.

GLN-2617Adams, Cambridge, C 232Cat. BN Hung., K2CDM, p. 88Drummond, Aberdeen, n° 864Fletcher-Smith, New South Wales, n° 453Kecskeméti, Estienne, n° 103Malicki, BJ 16, n° C-115Matagne, Moretus, C 10Messkataloge Willer, print. 1577, t. 2, p. [228].Shaaber, Univ. of Pennsylvania, C 39Shaw, Cathedral Libr., 2, C 122STC Edinburgh, p. 7

Fever and hypothermia represent two populations of sepsis patients and are associated with outside temperature

Background!#!Fever and hypothermia have been observed in septic patients. Their influence on prognosis is subject to ongoing debates.!##!Methods!#!We did a secondary analysis of a large clinical dataset from a quality improvement trial. A binary logistic regression model was calculated to assess the association of the thermal response with outcome and a multinomial regression model to assess factors associated with fever or hypothermia.!##!Results!#!With 6542 analyzable cases we observed a bimodal temperature response characterized by fever or hypothermia, normothermia was rare. Hypothermia and high fever were both associated with higher lactate values. Hypothermia was associated with higher mortality, but this association was reduced after adjustment for other risk factors. Age, community-acquired sepsis, lower BMI and lower outside temperatures were associated with hypothermia while bacteremia and higher procalcitonin values were associated with high fever.!##!Conclusions!#!Septic patients show either a hypothermic or a fever response. Whether hypothermia is a maladaptive response, as indicated by the higher mortality in hypothermic patients, or an adaptive response in patients with limited metabolic reserves under colder environmental conditions, remains an open question. Trial registration The original trial whose dataset was analyzed was registered at ClinicalTrials.gov (NCT01187134) on August 23, 2010, the first patient was included on July 1, 2011