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A Kashuba

Publications and source records attributed to A Kashuba.

6 recordsLinked to original sources

Domain instability during magnetization precession.

Spin wave equations describing the nonequilibrium precessional state of a ferromagnetic system are given. The equations reveal a new type of spin wave instability (SWI) towards growing domains of uniform magnetization. In the developed stages of SWI a nonstationary picture of domain chaos is revealed by numerical simulations. SWI is capable of explaining recent experimental observation of stochastic switching in precessional magnetization reversal.

Journal Article↗

Sensitivity and specificity of three clinical criteria for dementia with Lewy bodies in an autopsy-verified sample.

OBJECTIVE: To evaluate the sensitivity and specificity of the clinical features of three published diagnostic criteria for diffuse Lewy body disease (DLBD) using autopsy-confirmed Alzheimer's (AD), DLBD and AD+DLBD (mixed) dementia cases. DESIGN: Retrospective chart review of an autopsy series of 56 patients selected from the State of Florida Brain Bank on the basis of a pathological diagnosis of either pure AD, DLBD (pure and common forms) or AD+DLBD (mixed) dementia. Clinical features were assessed by three raters blind to the pathological diagnosis. RESULTS: The existing criteria for a clinical diagnosis of DLBD were highly specific (90-100%) but not very sensitive (49-63%) in the differential diagnosis of DLBD versus AD; sensitivity did improve (61-74%) when mixed AD+DLBD cases were eliminated. Clinical features that occur more frequently in DLBD than in AD were unspecified hallucinations, unspecified EPS, fluctuating course and rapid progression. Post-hoc analysis also indicated that hallucinations and EPS were more common early in the disease course of DLBD than in AD. Empirically derived criteria, formulated using the most prevalent clinical features, demonstrated sensitivity values of 57-96% for pure forms and 43-91% for mixed forms. CONCLUSIONS: This study demonstrated that additional improvements in the established criteria for DLBD are needed. Our empirically derived criteria enhanced the distinction of DLBD from AD while allowing the clinician the choice of maximizing sensitivity with acceptable specificity, and vice versa.

Aged↗

Assessment of the effects of dentifrices on plaque acidogenesis via intra-oral measurement of plaque acids.

Dionex ion chromatography was used for identification and quantification of the plaque acids (formate, lactate, acetate, and propionate) formed in vivo following a sucrose rinse. Consistent with other literature reports, lactate and acetate were the predominant acid species generated by plaque. This micro-analytical technique was used for investigation of the effects of dentifrice formulations containing NaF, xylitol, or NaF/xylitol on plaque acid metabolism. Neither a single nor multiple exposures (three times daily for one week) to the experimental dentifrices significantly altered the profiles of the individual acids or total plaque acidity relative to the placebo dentifrice. The lack of an effect of fluoride and xylitol on plaque acid metabolism is attributed to the variability of dental plaque and the low concentrations of active ingredients reaching the plaque. However, we believe that, with further improvement in sampling technique and study design, this approach may prove useful for the study of the effects of active ingredients (i.e., anticaries agents) on plaque acidogenesis.

Acetates↗