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T Mäntylä

Publications and source records attributed to T Mäntylä.

At least 19 recordsLinked to original sources
PubMed2000

Layer Buildup on Two-Layered Porous Substrate by Dip-Coating: Modeling and Effect of Additives on Growth Rate.

A model was developed to describe layer buildup on a two-layered substrate during dip-coating. In this model, the growth rate can be used to estimate the permeability of the cast layer. Layers of submicron alumina were dip-coated onto the asymmetric porous substrate to evaluate the model. The layer buildup and properties were studied with different slip additives. Slips were deflocculated with nitric acid or sodium poly(methacrylic acid) (Na-PMAA) to achieve electrostatic or electrosteric stabilization. Properties of the slips with electrostatic stabilization were varied with poly(vinyl alcohol) (PVA) concentration. Properties of the slips with electrosteric stabilization were varied with Na-PMAA concentration. PVA addition decreased the growth rate of the layer by reducing capillary pressure and increasing the viscosity of the filtrate. Electrostatic stabilization of the slip with PVA addition also led to almost complete deflocculation and a rather high density of layers. Na-PMAA addition led to fast growth of the layer. Na-PMAA addition increased the capillary pressure and had a minor effect on the viscosity of the liquid phase. Na-PMAA addition led to an incomplete dispersion of particles and therefore a high porosity of layers. Permeability values of coated layers obtained from the model were compared with permeability values predicted by the Kozeny-Carman equation. In the case of complete deflocculation of the slip, the permeability values estimated with the model correlated reasonably well with the predicted values. Incomplete deflocculation led to higher permeability values than predicted by the Kozeny-Carman equation. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Expression of CYP1A1, CYP1B1 and CYP3A, and polycyclic aromatic hydrocarbon-DNA adduct formation in bronchoalveolar macrophages of smokers and non-smokers.

Variability in the expression of enzymes metabolizing carcinogens derived from cigarette smoke may contribute to individual susceptibility to pulmonary carcinogenesis. This study was designed to determine the effects of smoking and 3 major cytochrome P450 (CYP) enzymes, i.e., CYP1A1, CYP1B1 and CYP3A, which metabolize polycyclic aromatic hydrocarbons (PAH) on PAH-DNA adduct formation in the bronchoalveolar macrophages (BAM) of 31 smokers and 16 non-smokers. CYP protein levels were determined by immunoblotting and PAH-DNA adduct levels by the nuclease P1 enhanced (32)P-postlabeling method. The expression of specific CYP forms was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR) from 10 additional samples. CYP3A protein, CYP3A5 by RT-PCR, was detected in the majority of samples from smokers and non-smokers. The levels of CYP3A appeared to be lower in active smokers than in ex-smokers (p = 0.10) or never smokers (p = 0.02). CYP1A1 was not detectable by either immunoblotting or RT-PCR. The expression of CYP1B1 was low or undetectable in most samples. The PAH-DNA adduct levels were higher (mean 1.57/10(8) nucleotides) in samples from smokers compared with non-smokers (mean 0.42/10(8) nucleotides, p < 0.001) and the number of adducts correlated with the number of cigarettes smoked daily (regression analysis, p < 0. 001). Higher levels of adducts were detected in samples from smokers with a high level of CYP3A compared with those with a low level (regression analysis, p = 0.002). As CYP3A5 is abundant in both lung epithelial cells and BAM, its association with adduct formation suggests that this CYP form may be important in the activation of cigarette smoke procarcinogens.

Adult↗
PubMed1997

Interrupting intentions: Zeigarnik-like effects in prospective memory.

In two experiments, we examined the effects of task interruption on memory for intentions. Participants studied a series of anagrams, of which they solved one-half (Exp. 1) or two-thirds (Exp. 2), whereas the solution of the remaining items was interrupted by the experimenter. Furthermore, four anagrams (prospective cue items) differed from the remaining anagrams in that the third letter of each item was underlined. Participants were instructed to decide whether a subsequently presented (target) anagram contained the same or a different third letter as the underlined letter of the cue item. The results of both experiments showed Zeigarnik-like effects in prospective memory, so that cue items that were associated with interruption in the anagram task were better reminders than were items that were associated with completion. These findings suggest that interruption of an ongoing activity facilitates subsequent prospective memory performance, possibly by increasing the level of activation of the underlying intention representation that, in turn, increases the individual's sensitivity to identify the target event.

Adult↗
PubMed1997

Recollections of faces: remembering differences and knowing similarities.

Components of recollective experience were investigated in 4 experiments in which participants studied either similarities or differences among faces (relational vs. distinctive processing). Subsequently, when recognizing a face, participants indicated whether their decision was based on explicit recollection (remembering) or assessment of familiarity (knowing). Type of encoding interacted with judgments of recollective experience, so that the incidence of "remember" responses was higher following distinctive encoding than following relational encoding, whereas the opposite pattern of results was obtained for "know" responses. Furthermore, recognition of appearance-changed faces was based on feelings of familiarity, rather than on explicit recollection. The results support the dual-component notion of recognition but are inconsistent with the idea that dissociations between remembering and knowing merely reflect differences in conceptual and perceptual processing.

Adult↗
PubMed1996

Adult age differences in source recall: a population-based study.

Age differences in source recall were investigated in a population-based sample of healthy adults aged 35 to 80 years (N = 1000). Participants, who were screened on a variety of demographic, psychological, and biological variables, studied facts about well-known and unknown persons that were presented in four different ways, depicting four different sources of item information. An age-related deterioration of both item and source recall was observed, with source recall being more impaired than item recall. Source error analyses revealed an increase of source amnesia in subjects aged 75-80 years. Individual differences in background variables, age, gender, and word comprehension were related to source recall of well-known items, whereas age and years of formal education were related to source recall of unknown items. Source amnesia was accentuated in the two oldest cohorts and related to word comprehension. The age-related tendency to forget the source even when the fact is retained is suggested to be a specific feature of cognitive aging.

Adult↗
PubMed1996

Asbestos bodies in bronchoalveolar lavage in relation to asbestos bodies and asbestos fibres in lung parenchyma.

In Finland, unlike other countries, anthophyllite asbestos has been widely used due to its domestic production in 1918-1975. In this particular context, the aim of the present study was to analyse the relationship between asbestos bodies (ABs) in bronchoalveolar lavage (BAL) fluid and the concentration of ABs and the different amphibole asbestos fibres in lung tissue. Sixty five BAL lung tissue sample pairs from patients with pulmonary disease were analysed. The concentration of ABs in BAL fluid and lung tissue was determined with optical microscopy, and the concentration, type and dimensions of asbestos fibres in lung tissue with scanning electron microscopy. There was a significant correlation between the concentrations of ABs in BAL fluid and in lung tissue (r = 0.72; p < 0.001), between the concentrations of ABs and amphibole asbestos fibres in lung tissue (r = 0.73; p < 0.001), and between the concentration of ABs in BAL fluid and the concentration of amphibole asbestos fibres in lung tissue (r = 0.64; p < 0.001). In patients who had been exposed mainly to commercial anthophyllite, significantly higher concentrations of ABs were observed per total pulmonary amphibole fibre burden, as compared to patients whose main exposure was to crocidolite/amosite. The anthophyllite fibres in lung tissue were longer than the crocidolite/amosite fibres. The relationship between asbestos body counts in lung tissue and in bronchoalveolar lavage fluid was similar to previous international observations. When using the asbestos body count to predict the underlying total pulmonary amphibole asbestos burden in Finnish patients, however, it should be borne in mind that the relationship between the two parameters seems to be different with anthophyllite as compared to crocidolite/amosite fibres.

Adult↗
PubMed1995

Recognition failure of categorised words: further evidence of exceptions.

When subjects study a list of B items paired with A items and are tested for recognition of the B items alone, and then for recall of the B items given the A items as cues, B items that can be recalled frequently go unrecognised. The extent of this recognition failure is predictable from a function discovered by Tulving and Wiseman (1975), which relates the probability of recognising the recallable items to the probability of recognising all items. Two kinds of exceptions to this function have been discovered: encoding exceptions and retrieval exceptions. Very few observations of retrieval exceptions exist. Four experiments described in this article provide further evidence that such exceptions occur when the B items are categorised and the A items are the names of the categories. According to a contextual account of the function and exceptions to it, these retrieval exceptions occur because the information provided by the A-item cues can be largely retrieved from the B items in the recognition test; hence, as cues, the A items do not provide much different contextual information to that provided by the B items. By this account, the function is an empirical law; exceptions fall outside the range of this law and define its boundary conditions.

Adolescent↗
PubMed1994

Asbestos bodies in bronchoalveolar lavage fluid in relation to occupational history.

Concentrations of asbestos bodies (AB) were assessed by optical microscopy of 10 ml iron-stained samples and compared with the exposure history acquired by personal interview for 156 patients. Concentrations equalling or exceeding 1 AB/ml were found in 85% of patients who had been heavily exposed to asbestos and only 7% of those who were unlikely to have been exposed. Elevated AB concentrations were observed among primary asbestos, shipyard and construction workers. Smoking was not found to affect the AB concentrations. The use of Papanicolaou-stained cytological Millipore preparations during routine screening was a less sensitive method for the assessment of AB concentrations than that involving iron-stained preparations. The expression of AB concentration as AB/ml or AB/million cells were found to be equally useful indicators of exposure. The correlation between AB concentration and exposure history was greater than in earlier studies on workers exposed to chrysotile. Concentrations exceeding 1 AB/ml were indicative of a nontrivial exposure to asbestos. Despite the observed correlation between AB concentration and exposure history, the individual variability of AB counts, methodological differences and laboratory-bound reference values are important in the interpretation of AB concentrations in bronchoalveolar lavage (BAL) fluid at individual level.

Adult↗
PubMed1994

Effectiveness of self-generated cues in early Alzheimer's disease.

The ability to utilize cognitive support in the form of self-generated cues in mild Alzheimer's disease (AD), and the factors promoting efficient cue utilization in this group of patients, were examined in two experiments on memory for words. Results from both experiments showed that normal old adults as well as AD patients performed better with self-generated cues than with experimenter-provided cues, although the latter type of cues resulted in gains relative to free recall. The findings indicate no qualitative differences in patterns of performance between the normal old and the AD patients. For both groups of subjects, cue effectiveness was optimized when (a) there was self-generation activity at encoding, and (b) encoding and retrieval conditions were compatible.

Aged↗
PubMed1994

Remembering to remember: adult age differences in prospective memory.

Age-related differences in prospective memory were examined in a laboratory-based task in which younger and older adults performed different actions whenever a semantically defined target word occurred in the context of a free-association task. Requirements for self-initiated retrieval operations were manipulated by presenting target words that were typical or atypical instances (e.g., milk vs ink) of a given semantic category (liquid). The results showed that age differences in prospective memory were accentuated when atypical items were used as targets, but reduced when highly typical targets were presented. Furthermore, age differences were not limited to remembering when to perform action, but young subjects also showed better performance in remembering what was to be done. These findings indicate that the magnitude of age difference in prospective memory interacts with task complexity, and support the view that prospective memory failures are accentuated in tasks with high resource demands on self-initiated retrieval operations.

Adult↗
PubMed1994

Components of recollective experience in cued recall.

Components of recollective experience were examined in relation to cue effectiveness by presenting subjects with their own or someone else's associations as retrieval cues. When recalling an item, subjects indicated whether they consciously recollected its prior occurrence ("remembering") or recalled it on some other basis, in the absence of conscious recollection ("knowing"). The results showed that cue compatibility (self-generated vs. someone else's cues) and retention interval (immediate vs. delayed test) selectively impaired retention accompanied by recollective experience, as measured by remember responses, but had reduced effects in the absence of recollective experience, as measured by know responses. The results are discussed in terms of variables dissociating judgments of recollective experience.

Adult↗
PubMed1993

Priming effects in prospective memory.

The objective of this study was to examine whether an increased activation of knowledge structures facilitates memory for future actions. Priming effects were manipulated by giving subjects a category fluency task for half of the target categories used in the subsequent prospective memory task. In this task, younger and older adults performed an action whenever an instance of a given semantic category occurred in the context of a free association task. The degree of retrieval support was varied by using typical and atypical category instances as targets. Although reliable priming effects were observed for both age groups, the magnitude of priming interacted with the degree of retrieval support. Older adults showed priming effects for typical targets only, whereas the opposite pattern of results was obtained for younger adults. These findings indicate that, in addition to retrieval-related factors, the operations performed at the time of planning also contribute to optimal prospective remembering.

Adult↗
PubMed1993

Prior knowledge and face recognition in a community-based sample of healthy, very old adults.

This experiment addressed the effects of prior knowledge on episodic face recognition in a community-based sample of healthy older adults from 75 to 96 years of age (N = 228). Subjects were presented with photographs of public Swedish individuals who attained their fame during the 1930s and 1940s, or during the 1980s. Results indicated an overall deterioration of face recognition performance across age. However, performance was higher with the dated than with the contemporary faces across the entire age range, suggesting that the ability to utilize prior knowledge in the context of face recognition is well preserved in very old age. Finally, a multiple regression analysis indicated that, among a variety of demographic, psychometric, and biological variables, age was the best predictor of face recognition performance.

Aged↗
PubMed1993

Knowing but not remembering: adult age differences in recollective experience.

Age differences in recollective experience were examined in two experiments in which younger and older adults used their self-generated associations as retrieval cues. When recalling an item, subjects indicated whether they consciously remembered its prior occurrence, or merely knew that it was presented previously. The results of both experiments showed that aging selectively impaired retention accompanied by recollective experience, as measured by remember responses, but had no effects in the absence of recollective experience, as measured by know responses. In Experiment 2, a similar pattern of data was obtained for a group of younger adults by increasing the rate of presentation at study. The results also indicated that judgments of recollective experience were related to type of encoding: Subjects who generated detailed associations reported higher levels of remember responses and lower levels of know responses than did subjects who generated fewer detailed associations. The results are discussed in terms of processes related to perceptual familiarity and contextual detail.

Adult↗
PubMed1992

Aging and memory for expected and unexpected objects in real-world settings.

Adult age differences in the consistency effect were examined in 3 experiments. The consistency effect refers to items inconsistent with expectations being better remembered than items consistent with expectations. Younger and older adults walked into an office room and viewed objects that varied in their consistency with expectation. Immediate and delayed recognition tests on item information (i.e., distractors were defined by their semantic identity) revealed that both age groups recognized unexpected items better than expected items. However, when recognition of token information was requested (i.e., distractors were defined by their physical appearance), younger adults, in contrast to older adults, exhibited consistency effects. Also, under divided attention, young adults revealed the same pattern of data as did elderly adults under full attention. The results are discussed in terms of capacity-related differences in distinctive encoding.

Adult↗
PubMed1990

Encoding variability and age-related retrieval failures.

The hypothesis that an age-related decrease in consistency of processing may contribute to age-related deficits in episodic remembering was examined in 2 experiments. Older and younger adults generated properties to a series of target words on 2 occasions. Encoding variability was determined by calculating the degree of intra- and intersubject overlap of properties generated on both occasions. Experiment 1 showed that older adults' interpretations varied more than those of younger adults. Furthermore, older adults were less idiosyncratic in their descriptions than were younger adults. Experiment 2 replicated this pattern of results and showed that the observed age-related decrease in consistency of processing was associated with age-related retrieval failures. An age-related decrease in distinctiveness of encoding was proposed as a factor underlying age differences in consistency that, in turn, is assumed to contribute to age-related deficits in episodic remembering.

Adult↗
PubMed1988

Effectiveness of self-generated cues in younger and older adults: the role of retention interval.

Younger and older participants generated one or three properties to a set of forty nouns. Immediately after, one week after, or three weeks after this generation phase, the participants received an incidental recall test, in which they were cued with their self-generated properties, and requested to recall the nouns. Although the younger adults recalled more nouns than the older participants in all conditions, both age groups exhibited an extremely high level of immediate recall. In addition, younger and older adults did not differ with respect to the forgetting rate, and both age groups recalled more nouns when three, as compared to one, properties were provided as cues. It is suggested that cue effectiveness is optimized both for younger and older adults when the cues describing the information encoded are compatible and distinctive. Finally, it is emphasized that the individual's idiosyncratic knowledge may serve an important function in attempts at optimizing memory performance of elderly people.

Adult↗