Overview and update.

A summary of points of agreement and disagreement among the preceding articles is presented. Attention is called to implicit assumptions which if openly acknowledged would improve dialogue on peer review issues. Pertinent events that have occurred since the Anaheim symposium are reviewed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The validity of new memory complaints in the elderly

OBJECTIVE: To determine the validity of new subjective memory complaints (MCs) from individuals who previously, when without dementia, denied having MCs. DESIGN: Prospective cohort. SETTING: Longitudinal, community-based study of aging and dementia. PATIENTS: One hundred thirty-three community-dwelling elderly individuals who were part of a registry for the study of conditions related to aging in North Manhattan, NY. Patients were selected if they were initially without dementia and had completed at least 2 successive annual clinical and neuropsychological evaluations and provided their own medical history. MAIN OUTCOME MEASURES: Performance on memory tests--the Buschke Selective Reminding Test and a visual memory task--and global performance on a neuropsychological test battery and clinical evaluation, by which questionable dementia or dementia was diagnosed according to a well-defined paradigm. RESULTS: Fifty-three subjects with MCs at the initial evaluation performed no worse on the memory test than the 80 subjects who denied MCs initially. There was a weak association between MCs and the diagnosis of questionable dementia at baseline (P = .04), but this was nonsignificant after adjusting for age and education. At 1-year follow-up, 21 of the 80 without baseline MCs now reported MCs. At the follow-up evaluation, these 21 subjects performed significantly worse on the memory tests, were 5 times more likely to have significant cognitive impairment, and had shown significantly greater decline over the preceding year on several of the cognitive measures than the 59 who continued to deny MCs. CONCLUSION: New MCs from individuals, who when without dementia recently denied MCs, may suggest the presence of significant impairment of memory or cognition.     

MAGNESIUM HYDROXIDE FILLED EVA: THE EFFECTS OF FILLER SURFACE MODIFICATION ON THE STRENGTH OF FILLER/MATRIX ADHESION AND THE CONSEQUENCES FOR COMPOSITE STRUCTURE AND PROPERTIES

The interaction of ammonium stearate (AS) and γ-aminopropyltriethoxysilane (APS) treatments with a magnesium hydroxide flame retardant filler and their effects on its use in an ethylene vinyl acetate copolymer compound have been investigated. The work has shown clear evidence of changes in the structure of the surface layers formed on the filler as the amount of additive is increased and the levels at which these occur can be correlated with theoretical monolayer quantities. Infrared (IR) spectroscopy data suggest that the stearate coating changes from a half salt to a full salt as the coating level is increased and that the APS coating on the filler initially has a significant bicarbonate content, presumably due to reaction with atmospheric carbon dioxide. The effect of coating level on the melt flow rate, insoluble matrix content, crystallisation behaviour, tensile properties, limiting oxygen index, and ageing of the filled compound has been studied. Distinct trends have been observed, many of which can be correlated with the structure of the filler surface layers. Of particular importance is the observation that, unlike APS, excess stearate appears to promote detrimental ageing effects.     

Formal methods: The next generation of system design tools

Because of the growing demand for increasingly complex computer-based systems there is now an urgent need to provide tools to assist during the design of such systems. Formal specifications and formal methods provide such assistance but their widespread adoption has been hindered by the so-called ‘math fear’ and the perception that the tools are too difficult, too time consuming and too costly to use in a commercial environment. The aim of this article is to dispel the mystery surrounding the topic and to explain what formal methods are, how and why they are used, the benefits that accrue and why the technology should be accepted on a broader front. The application of formal methods to the design of computer-based systems will be discussed without resorting to jargon or mathematics. The discussion will concentrate more on the software content of systems but the arguments apply equally well to hardware. Some of the available tools will also be introduced.     

Inhibition of TEM-2 beta-lactamase from Escherichia coli by clavulanic acid: observation of intermediates by electrospray ionization mass spectrometry

Clavulanic acid, the therapeutically important inhibitor of beta-lactamases containing a nucleophilic serine residue at their active sites, inhibits Escherichia coli TEM-2 beta-lactamase via a complex mechanism. Electrospray ionization mass spectrometry (ESIMS) studies revealed that a minimum of four different modified proteins are formed upon incubation of clavulanate with the TEM-2 enzyme. These exhibit mass increments relative to the unmodified TEM-2 beta-lactamase of 52, 70, 88, and 155 Da. Time course studies implied that no long-lived forms of clavulanate-inhibited TEM-2 beta-lactamase retain the carbons of the oxazolidine ring of clavulanate. The absence of a 199 Da increment to unmodified TEM-2 suggests rapid decarboxylation of clavulanate upon binding to the enzyme. Proteolytic digestions of purified forms of clavulanate inhibited TEM-2 beta-lactamase followed by analyses using high-performance liquid chromatography coupled to ESIMS (HPLC-ESIMS) and chemical sequencing were used to provide positional information on the modifications to the enzyme. Increments of 70 and 80 Da increments were shown to be located in a peptide containing Ser-70. A further 70 Da mass increment, assigned as a beta-linked acrylate, was localized to a peptide containing Ser-130. A mechanistic scheme for the reaction of clavulanate with TEM-2 beta-lactamase is proposed in which acylation at Ser-70 and subsequent decarboxylation is followed either by cross-linking with Ser-130 to form a vinyl ether or by reformation of unmodified enzyme via a Ser-70 linked (hydrated) aldehyde. Purified cross-linked vinyl ether was observed to slowly convert under acidic conditions to a Ser-70 linked (hydrated) aldehyde with concomitant conversion of Ser-130 to a dehydroalanyl residue.     

Plasma alloying and spheroidization process and development

Elemental and blended refractory metal powders were processed using a plasma alloying and spheroidization (PAS) process. The powders were characterized to determine changes in chemistry and morphology after processing. Five refractory metal powders were evaluated during this investigation: (1) crystalline W, (2) spray dried Mo, (3) W-25 wt.% Re composite powder, (4) W-2 wt.% Re composite powder, and (5) Mo-40 wt.% Re composite powder. Benefits of the PAS process, such as a two-order of magnitude reduction in oxygen contamination, production of highly spherical powders for enhanced flow characteristics, and the ability to produce prealloyed powders were demonstrated. This paper was presented at the 2nd International Surface Engineering Congress sponsored by ASM International, on September 15–17, 2003, in Indianapolis, Indiana, and appears on pp. 441–47 of the Proceedings.     

Nightingallery: theatrical framing and orchestration in participatory performance

The Nightingallery project encouraged participants to converse, sing, and perform with a musically responsive animatronic bird, playfully interacting with the character while members of the public could look on and observe. We used Nightingallery to frame an HCI investigation into how people would engage with one another when confronted with unfamiliar technologies in conspicuously public, social spaces. Structuring performances as improvisational street theatre, we styled our method of exhibiting the bird character. We cast ourselves in supporting roles as carnival barkers and minders of the bird, presenting him as if he were a fantastical creature in a fairground sideshow display, allowing him the agency to shape and maintain dialogues with participants, and positioning him as the focal character upon which the encounter was centred. We explored how the anthropomorphic nature of the bird itself, along with the cultural connotations associated with the carnival/sideshow tradition helped signpost and entice participants through the trajectory of their encounters with the exhibit. Situating ourselves as secondary characters within the narrative defining the performance/use context, our methods of mediation, observation, and evaluation were integrated into the performance frame. In this paper, we explore recent HCI theories in mixed reality performance to reflect upon how genre-based cultural connotations can be used to frame trajectories of experience, and how manipulation of roles and agency in participatory performance can facilitate HCI investigation of social encounters with playful technologies.     

The chemical nature of combustion deposition and corrosion: The case of alkali chlorides

Quantitative deposition studies are reported involving flame gases containing traces of sodium and chlorine. Comparisons with previously published and unpublished data involving Na₂SO₄ and Na₂CO₃ deposition indicate a similar behavior and a generic type mechanism. A wide series of propane and hydrogen flames of varying equivalence ratio have been examined that contain sodium on a part per million by volume scale (ppmv) and chlorine either as a similar trace amount or in excess. An important aspect is that deposition is efficient and the product does not directly correlate to the gas-phase metal speciation. Whether sodium is present as gaseous NaCl, NaOH or Na in a flame is irrelevant to the composition of the deposit. Rates are controlled by the total amount of sodium reaching the surface. Once there, the flame becomes solely a provenience of preferred ingredients. Below 850 K, formation rates of NaCl, Na₂CO₃ or Na₂SO₄ are the same, and for Na/Cl containing flames the ranking is NaCl > Na₂CO₃ > NaOH as predicted by thermodynamics. Rates are first-order in alkali and zero-order for chlorine concentrations. They are independent of equivalence ratio, flame temperature, flow velocity, or temperature gradient across the surface boundary layer. Compositional analyses of deposits indicate that below 850 K, where NaCl vaporization is negligible, a several fold excess of chlorine over sodium is required to produce the theoretically predicted 100% deposit of NaCl. The data suggest slight kinetic constraints relating to the chlorine concentrations, which might imply conversions of transient hydroxide or carbonate. Deposition of NaCl continues to higher temperatures but rapidly becomes short-lived due to vaporization. Deposition processes are seen as a steady state balance between a perpetual influx and egress of materials at all temperatures. In this regard, steel corrosion by NaCl is reported above its ‘dew point’ with the formation of Na₂CrO₄.