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PubMed2000

Single vessel procedure for acid-vapour partial digestion in a focused microwave: Fe and Co determination in biological samples by ETAAS.

A single vessel procedure using a focused microwave oven is proposed for biological sample preparation with nitric acid vapour under atmospheric pressure. A laboratory-made PTFE support vessel equipped with four cups that received the samples was adapted to fit on the microwave glass vessel. Biological samples (30 mg) were directly weighed into these PTFE cups followed by the addition of 150 microliters of water or H2O2. The mixture was exposed to acid vapour stemming from 15 ml of concentrated HNO3 placed in the bottom of the glass vessel. The acid vapour was formed at 115 degrees C and brought about the Co and Fe extraction in 10 and 60 min, respectively. The resulting suspension was diluted with 0.14 mol l-1 HNO3 to a final volume of 1.0 ml, shaken and centrifuged. The supernatant was analysed by electrothermal atomic absorption spectrometry (ETAAS) by placing the cups directly in the autosampler of the spectrometer. This system minimised contamination, and reagent and time consumption and was suitable for Co and Fe determination in biological materials. The accuracy of the proposed method was assessed by using certified reference materials and by comparison with the closed vessel microwave as a comparative technique. Cobalt and Fe recovery was around 82-99%. As an additional advantage, up to 6 samples can be simultaneously prepared in each vessel, thereby improving the sample throughput from 6 to 24, when a 6-cavity focused microwave is used.

Animals↗
PubMed1981

[Lead intake with food of young infants in the years 1980/81 (author's transl)].

Several studies related minimal cerebral dysfunction in children to environmental lead exposure. We calculated the lead intake of young infants based on measurements of the lead content in their food. There was no significant difference between the lead content of 13 samples of pooled breast milk (50.2 +/- 22.5 micrograms/l), 11 samples of adapted and followup formulas (67.4 +/- 9.9 micrograms/l) and 9 samples of cow milk (59.5 +/- 22.5 micrograms/l). In fruits, commercially prepared strained fruits and juices lead concentrations were between 18.7 and 123.6 micrograms/kg. Based on the mean concentration of all products we calculated the average lead content in an infant's fruit or juice dinner to be 67 micrograms/kg. In plain and creamed vegetables lead concentrations were between 98.2 and 204.0 micrograms/kg, with the highest lead content in potatoes, spinach and carrots. The average lead content in an infant's plain or creamed vegetable dinner was 117 micrograms/kg. The lead intake over the first 6 months of life was calculated from the above-mentioned data and the average amount of food consumed per day. It was found to be below the maximum daily permissible intake from all sources. However, especially after introduction of mixed feeding (vegetables!) at the age of 4 months, the daily lead intake was close to the tolerance limit. There was no evidence of lead contamination during production of commercially-prepared baby food. Environmental contamination seems to be the main reason for the high lead content in infant food, especially in vegetables.

Animals↗
PubMed2003

Parasite contamination (helminth eggs) in sludge treatment plants: definition of a sampling strategy.

The use of sludge in agriculture must be carried out according to many guidelines, especially regarding a precise knowledge of the pathogenic microorganisms it contains. The control of the produced sludge requires a sampling strategy that is representative of the contamination present in the sludge. Thus, we evaluated the distribution of helminth eggs in sludge to determine how to sample and at what frequency. Two plants were studied, firstly we studied sludge that was undergoing biological treatment (anaerobic digestion, prolonged aeration), secondly we evaluated the dehydration step (centrifugation and filter press). The helminth egg concentrations were measured over short periods (between 5 minutes and 7 hours) and for periods of over 24 hours (7 to 28 days). The results showed that there was much homogeneity in periods of less than 7 hours, thus it was advisable to take grab samples. An appropriate sample weight was 30 g dry matter, because this allowed an analysis in triplicate when testing treatment processes according to standards of France, (less than 3 viable eggs/10 g dry matter). Determination of the egg concentration in the plants during periods of over 24 hours showed that the parasite flow was stable. In some cases, large variations were due to the treatment processes (storage or thickening, mixing of different sludges). These results have been confirmed with the study of 6 other plants during a one year period. Thus, the recommended sampling frequency can be limited to every 3 to 6 months, by adapting the sampling methods to the characteristics of the plant.

Agriculture↗
PubMed2001

Efficient transition path sampling for nonequilibrium stochastic dynamics.

The transition path sampling methodology is adapted to the efficient sampling of large fluctuations in nonequilibrium systems evolving according to Langevin's equations of motion. This technique is used to simulate the behavior of the bistable Maier-Stein system at noise intensities much lower than those previously possible.

Journal Article↗
PubMed2002

New technique (the NOW test) for rapid detection of Streptococcus pneumoniae in the nasopharynx.

Although the NOW test was originally introduced as a rapid pneumococcal antigen detection test for use with urine samples, it was successfully adapted to nasopharyngeal samples in the present study. The sensitivity, specificity, positive predictive value, and negative predictive value of the test were 92.2, 97.7, 95.9, and 95.5%, respectively. These results demonstrate that nasopharyngeal colonization with Streptococcus pneumoniae can be documented within 15 min of sample collection.

Adolescent↗
PubMed1990

The Self-Adapting Focused Review System. Probability sampling of medical records to monitor utilization and quality of care.

Medical record review is increasing in importance as the need to identify and monitor utilization and quality of care problems grow. To conserve resources, reviews are usually performed on a subset of cases. If judgment is used to identify subgroups for review, this raises the following questions: How should subgroups be determined, particularly since the locus of problems can change over time? What standard of comparison should be used in interpreting rates of problems found in subgroups? How can population problem rates be estimated from observed subgroup rates? How can the bias be avoided that arises because reviewers know that selected cases are suspected of having problems? How can changes in problem rates over time be interpreted when evaluating intervention programs? Simple random sampling, an alternative to subgroup review, overcomes the problems implied by these questions but is inefficient. The Self-Adapting Focused Review System (SAFRS), introduced and described here, provides an adaptive approach to record selection that is based upon model-weighted probability sampling. It retains the desirable inferential properties of random sampling while allowing reviews to be concentrated on cases currently thought most likely to be problematic. Model development and evaluation are illustrated using hospital data to predict inappropriate admissions.

Bias↗
PubMed2004

An adapted version of the U.S. Department of Agriculture Food Insecurity module is a valid tool for assessing household food insecurity in Campinas, Brazil.

Until recently, Brazil did not have a national instrument with which to assess household food insecurity (FI). The objectives of this study were as follows: 1) to describe the process of adaptation and validation of the 15-item USDA FI module, and 2) to assess its validity in the city of Campinas. The USDA scale was translated into Portuguese and subsequently tested for content and face validity through content expert and focus groups made up of community members. This was followed by a quantitative validation based on a convenience (n = 125) and a representative (n = 847) sample. Key adaptations involved replacing the term "balanced meal" with "healthy and varied diet," to construct items as questions rather than statements, and to ensure that respondents understood that information would not be used to determine program eligibility. Chronbach's alpha was 0.91 and the scale item response curves were parallel across the 4 household income strata. FI severity level was strongly associated in a dose-response manner (P < 0.001) with income strata and the probability of daily intake of fruits, vegetables, meat/fish, and dairy. These findings were replicated in the 2 independent survey samples. Results indicate that the adapted version of the USDA food insecurity module is valid for the population of Campinas. This validation methodology has now been replicated in urban and/or rural areas of 4 additional states with similar results. Thus, Brazil now has a household food insecurity instrument that can be used to set national goals, to follow progress, and to evaluate its national hunger and poverty eradication programs.

Adult↗
PubMed2003

Cool walking: a new Markov chain Monte Carlo sampling method.

Effective relaxation processes for difficult systems like proteins or spin glasses require special simulation techniques that permit barrier crossing to ensure ergodic sampling. Numerous adaptations of the venerable Metropolis Monte Carlo (MMC) algorithm have been proposed to improve its sampling efficiency, including various hybrid Monte Carlo (HMC) schemes, and methods designed specifically for overcoming quasi-ergodicity problems such as Jump Walking (J-Walking), Smart Walking (S-Walking), Smart Darting, and Parallel Tempering. We present an alternative to these approaches that we call Cool Walking, or C-Walking. In C-Walking two Markov chains are propagated in tandem, one at a high (ergodic) temperature and the other at a low temperature. Nonlocal trial moves for the low temperature walker are generated by first sampling from the high-temperature distribution, then performing a statistical quenching process on the sampled configuration to generate a C-Walking jump move. C-Walking needs only one high-temperature walker, satisfies detailed balance, and offers the important practical advantage that the high and low-temperature walkers can be run in tandem with minimal degradation of sampling due to the presence of correlations. To make the C-Walking approach more suitable to real problems we decrease the required number of cooling steps by attempting to jump at intermediate temperatures during cooling. We further reduce the number of cooling steps by utilizing "windows" of states when jumping, which improves acceptance ratios and lowers the average number of cooling steps. We present C-Walking results with comparisons to J-Walking, S-Walking, Smart Darting, and Parallel Tempering on a one-dimensional rugged potential energy surface in which the exact normalized probability distribution is known. C-Walking shows superior sampling as judged by two ergodic measures.

Journal Article↗
PubMedDate not supplied

Footprint area sampled texturing.

We study texture projection based on a four region subdivision: magnification, minification, and two mixed regions. We propose improved versions of existing techniques by providing exact filtering methods which reduce both aliasing and overblurring, especially in the mixed regions. We further present a novel texture mapping algorithm called FAST (Footprint Area Sampled Texturing), which not only delivers high quality, but also is efficient. By utilizing coherence between neighboring pixels, performing prefiltering, and applying an area sampling scheme, we guarantee a minimum number of samples sufficient for effective antialiasing. Unlike existing methods (e.g., MIP-map, Feline), our method adapts the sampling rate in each chosen MIP-map level separately to avoid undersampling in the lower level l for effective antialiasing and to avoid oversampling in the higher level l + 1 for efficiency. Our method has been shown to deliver superior image quality to Feline and other methods while retaining the same efficiency. We also provide implementation trade offs to apply a variable degree of accuracy versus speed.

Algorithms↗
PubMedDate not supplied

Bilateral recovering of sharp edges on feature-insensitive sampled meshes.

A variety of computer graphics applications sample surfaces of 3D shapes in a regular grid without making the sampling rate adaptive to the surface curvature or sharp features. Triangular meshes that interpolate or approximate these samples usually exhibit relatively big error around the insensitive sampled sharp features. This paper presents a robust general approach conducting bilateral filters to recover sharp edges on such insensitive sampled triangular meshes. Motivated by the impressive results of bilateral filtering for mesh smoothing and denoising, we adopt it to govern the sharpening of triangular meshes. After recognizing the regions that embed sharp features, we recover the sharpness geometry through bilateral filtering, followed by iteratively modifying the given mesh's connectivity to form singlewide sharp edges that can be easily detected by their dihedral angles. We show that the proposed method can robustly reconstruct sharp edges on feature-insensitive sampled meshes.

Algorithms↗
PubMed1989

Antigenic characterization of swine rotaviruses in Argentina.

Fecal samples from 156 diarrheic piglets were collected from several herds located in two main breeding areas of Argentina. Rotaviruses were detected in 60 samples (38.4%) by polyacrylamide gel electrophoresis and in 55 samples by a group A-specific enzyme-linked immunosorbent assay (ELISA). All samples which were positive by polyacrylamide gel electrophoresis and negative by ELISA had elicited atypical electropherotypes resembling those of group B or C. ELISA-positive samples showing genome rearrangements were also detected (R.C. Bellinzoni, N.M. Mattion, O.R. Burrone, S.A. González, J.L. La Torre, and E.A. Scodeller, J. Clin. Microbiol. 25:952-954, 1987; N.M. Mattion, S.A. González, O.R. Burrone, R.C. Bellinzoni, J.L. La Torre, and E.A. Scodeller, J. Gen. Virol. 69:695-698, 1988). By subgrouping with monoclonal antibodies, it was found that of 32 positive samples, 13 belonged to subgroup I, 2 belonged to subgroup II, 2 samples had both specificities, and 15 samples were neither subgroup I nor subgroup II (non-I/II). In addition, 10 samples were adapted to grow in tissue culture, cloned, and serotyped by means of neutralization assays. Two samples were classified as serotype 5, and none of them were classified as serotype 4. The other strains showed only a one-way relationship with serotype 5 and can be tentatively classified as new porcine serotypes. Two samples with rearranged genomes had a one-way relationship with antiserum to human strain 69M, which displays a supershort electropherotype and was classified as a new human serotype (S. Matsuno, A. Hasegawa, A. Mukoyama, and S. Inouye, J. Virol. 54:623-624, 1985). At one farm, similar rearranged strains were detected during three successive years. Serotype changes were found between the isolates of the first and the second year, suggesting that a high degree of antigenic variability went on during continuous circulation of these strains in the field.

Animals↗
PubMed2001

Modification of the sample size and the schedule of interim analyses in survival trials based on data inspections.

A method is presented which allows us to adapt the sample size as well as the number and time points of interim analyses to the treatment difference observed at an interim look during the course of a clinical trial with censored survival time as the endpoint. The method allows the inclusion of data inspections during the course of the trial and redesign of the trial on the basis of the observed treatment difference without affecting the type I error risk. Formulae for recalculating the required number of events and the number of further patients to be randomized as a function of the observed hazard rates and the detectable hazard ratio are given.

Carcinoma, Non-Small-Cell Lung↗
PubMed1986

Lowry protein assay using an automatic microtiter plate spectrophotometer.

The method of protein determination reported by Lowry et al. (1951, J. Biol. Chem. 193, 265-275) has been adapted for use with 96-well microtiter plates and an automatic microplate spectrophotometer. The spectrophotometer has been interfaced with a computer which plots the standard curve and calculates the protein content of each sample. The adapted method offers advantages over previously reported methods in that it is more rapid and uses a smaller sample volume (100 microliters) for samples containing 3-300 micrograms/ml (0.3-30 micrograms/assay) of protein. The method of Bensadoun and Weinstein (1976, Anal. Biochem. 70, 241-252) for precipitating microgram amounts of protein away from substances which interfere with the Lowry assay has also been adapted to this microplate procedure. These techniques should be particularly useful for laboratories where large numbers of samples containing a wide range of protein concentrations are assayed.

Animals↗
PubMedDate not supplied

Marginal and internal adaptation of class II restorations after immediate or delayed composite placement.

Direct class II composite restorations still represent a challenge, particularly when proximal limits extend below the CEJ. The aim of this in vitro study was to evaluate the influence of the type of adhesive and the delay between adhesive placement and composite insertion on restoration adaptation. Direct class II MOD box-shaped composite restorations (n=8 per group) were placed on intact human third molars, with proximal margins 1mm above or under CEJ. All cavities were filled with a horizontal layering technique, immediately after adhesive placement (IP) or after a 24h delay (DP). A filled three-component adhesive (OptiBond FL: OB) and a single-bottle, unfilled one (Prime & Bond 2.1: PB) were tested. Marginal adaptation was assessed before and after each phase of mechanical loading (250000 cycles at 50 N, 250000 cycles at 75 N and 500000 cycles at 100 N); internal adaptation was evaluated after test completion. Gold-plated resin replicas were observed in the SEM and restoration quality evaluated in percentages of continuity (C) at the margins and within the internal interface, after sample section. Adaptation to beveled enamel proved satisfactory in all groups. After loading, adaptation to gingival dentin degraded more in PB-IP (C=55.1%) than PB-DP (C=86.9%) or OB-DP (C=89%). More internal defects were observed in PB samples (IP: C=79.2% and DP: C=86.3%) compared to OB samples (IP: C=97.4% and DP: C=98.3%). The filled adhesive (OB) produced a better adaptation than the 'one-bottle' brand (PB), hypothetically by forming a stress-absorbing layer, limiting the development of adhesive failures. Postponing occlusal loading (such as the indirect approach) improved also restoration adaptation.

Acetone↗
PubMed2006

Immunomagnetic recovery of Mycobacterium bovis from naturally infected environmental samples.

AIMS: To adapt an immunomagnetic capture (IMC) technique to concentrate and cultivate Mycobacterium bovis from environmental samples including soil, faeces and urine. METHODS AND RESULTS: Cells of Myco. bovis BCG and wild-type Myco. bovis were successfully isolated and cultured from seeded and naturally infected materials respectively. The IMC cell recovery estimated by colony forming units (CFUs) counts ranged from 0.10% to 0.16% for spiked media, and 0.15-0.36% for naturally infected soil and faeces. Recovery estimated by cell counts calculated using semi-quantitative PCR ranged from 80.3% to 88.6% for spiked and 84.1-88.2% for naturally infected material. The differences in the recovery rates estimated by CFUs compared with pixel intensity is likely to be due to clustering of cells on culture plates, thereby underestimating the true cell count. CONCLUSIONS: The IMC techniques can be applied to isolate viable wild type Myco. bovis from naturally contaminated environmental samples. SIGNIFICANCE AND IMPACT OF STUDY: Cultivation of Myco. bovis from environmental samples using traditional methods is extremely problematic. Here, we demonstrate a novel development of IMC techniques that will greatly facilitate the study of the organism in situ in order to assess its epidemiological importance in bovine tuberculosis persistence.

Animals↗
PubMed1997

[Do psychological factors modify survival of cancer patients? I: Review of the literature].

The present paper addresses the question whether psychological factors influence the course of the disease in cancer patients. Studies investigating this issue are reviewed from a methodological point of view. The main objective is to design guidelines for future research. The review begins with Greer's and his co-workers' study on breast cancer patients. They demonstrated that ways of coping called fighting spirit and denial are predictive of longer survival. However, axillary lymph node status and oestrogen receptor status could not be controlled, because these measures had not been assessed on a routine basis at the time of diagnosis. The Greer study has been stimulating a series of replications. Moreover, investigations into patients with various other cancer sites including melanoma and lung cancer have been performed. In general, results were inconsistent. Studies with positive findings are contrasted by those with negative results. Within positive findings, results were partially contradictory. Moreover, most of the investigations suffered from serious methodological limitations rendering interpretation difficult. The following methodological conclusions can be drawn: Testing of a priori hypotheses instead of multiple retrospective tests; prospective design to prevent that psychological predictors turn out to be indicators of the somatic state of the patient; multi-method and longitudinal assessment of coping and adaptation; homogeneous sample; taking into account all known biological prognostic factors; multivariate statistical analysis.

Adaptation, Psychological↗
PubMedDate not supplied

Spanish version of the Rotterdam Symptom Check List: cross-cultural adaptation and preliminary validity in a sample of terminal cancer patients.

We report on the process of adaptation into Spanish of the Rotterdam Symptom Check List (RSCL). The original version was translated and back-translated by professional bilingual translators. A quantitative rating method was used to select the items to include in the final Spanish version. Validity (discriminant and construction) and reliability were test in 118 terminal cancer patients. In addition to the RSCL the Nottingham Health Profile (NHP) and the Karnofsky Performance Status (KPS) were used. The RSCL showed different ratings on all scales according to the functional level of the patients. The scales were moderately to highly correlated with the NHP (from 0.48 to 0.71). Internal consistency, measured by Cronbach's alpha coefficient ranged from 0.74 (physical) to 0.90 (activity). Twenty-four hours test-retest intraclass correlation coefficient ranged from 0.71 to 0.88. The results of this study suggest that the Spanish version of the RSCL is conceptually equivalent to the original. More research is needed to assess the responsiveness of the version before using it in clinical trials.

Activities of Daily Living↗