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Method validation for detection and quantification of cocoa butter equivalents in cocoa butter and plain chocolate.

A European interlaboratory study was conducted to validate an analytical procedure for the detection and quantification of cocoa butter equivalents in cocoa butter and plain chocolate. In principle, the fat obtained from plain chocolate according to the Soxhlet principle is separated by high-resolution capillary gas chromatography into triacylglycerol fractions according to their acyl-C-numbers, and within a given number, also according to unsaturation. The presence of cocoa butter equivalents is detected by linear regression analysis applied to the relative proportions of the 3 main triacylglycerol fractions of the fat analyzed. The amount of the cocoa butter equivalent admixture is estimated by partial least-squares regression analysis applied to the relative proportions of the 5 main triacylglycerols. Cocoa butter equivalent admixtures were detected down to a level of 2% related to the fat phase, corresponding to 0.6% in chocolate (assumed fat content of chocolate, 30%), without false-positive or -negative results. By using a quantification model based on partial least-squares regression analysis, the predicted cocoa butter equivalent amounts were in close agreement with the actual values. The applied model performed well at the level of the statutory limit of 5% cocoa butter equivalent addition to chocolate with a prediction error of 0.6%, assuming a chocolate fat content of 30%.

Cacao↗

PubMed1992

Update: serologic testing for human T-lymphotropic virus type I--United States, 1989 and 1990.

Human T-lymphotropic virus type I (HTLV-I)* is a retrovirus that has been identified as a cause of human T-cell leukemia/lymphoma and tropical spastic paraparesis; HTLV-II is closely related to HTLV-I but has not been linked to human illness. Both viruses can be transmitted through blood transfusion and injecting-drug use; therefore, accurate and reliable HTLV-I-antibody test results are essential to diagnose HTLV-I infection, conduct public health surveillance and prevention programs, and improve the safety of blood and blood products collected for transfusion (1). During 1989, CDC expanded its Model Performance Evaluation Program (MPEP) to assess the performance of laboratories that conduct HTLV-I-antibody testing and to identify potential problems in the testing process (2). This report summarizes findings of CDC's laboratory performance evaluation surveys.

Antibodies, Viral↗

PubMed2005

[Time factor in radiotherapy and chemotherapy for small cell lung cancer].

INTRODUCTION: Selection of treatment schedule in patients with small cell lung cancer (SCLC) appears to be a subject of controversies. One of the most controversial issue is influence of planned and unplanned gaps in radiotherapy and chemotherapy on efficacy of radical treatment of patients with limited disease. These controversies created the basis for current research. MATERIAL: 245 patients with LD-SCLC treated in Cancer Center in Gliwice between 1989 and 2001 were included in the present analysis. There were 60 women and 185 men, median age 58 years; All these patients were in good general condition. Cisplatine based chemotherapy and total radiation dose higher than 30Gy were used in all of them. METHODS: Overall survival was analyzed using Kaplan-Meier analysis. The variables potentially influencing overall survival including dose-intensity of chemotherapy and radiotherapy were analyzed using multivariate Cox regression model. RESULTS: 3-year actuarial overall survival in a whole group of patients was 10 percent. The following variables had negative influence on overall survival in multivariate Cox model: performance status ZUBROD higher than 0 (p<0.0001), metastases to supraclavicular nodes (p=0.001), dyspnoea according to Borg scale higher than 2 (p=0.004) and radiation dose intensity less than 80% (p=0.02). Gaps in chemotherapy did not appear significant. CONCLUSIONS: Radiation treatment gaps had significant negative influence on survival of the patients with LD-SCLC, while interruptions of chemotherapy did not. This may suggest that within the range of doses and dose-intensities used in this group, interruptions of chemotherapy due to treatment toxicity are justified, while interruptions of radiotherapy should be promptly avoided.

Antineoplastic Agents↗

PubMed1994

Analysis of cerebral concussion frequency with the most commonly used models of football helmets.

Data on helmet models used and occurrence of cerebral concussions over five seasons were collected from a representative sample of college football teams including a total of 8,312 player-seasons and 618,596 athlete-exposures to the possibility of being injured in a game or practice. Results showed that players with a history of concussion any time during the previous 5 years were six times as likely to suffer a new concussion as those with no previous history. In light of previous studies showing cognitive deficits for up to 30 days following even minor head injuries, and the growing awareness of "second impact" fatalities, these data support a need for reconsideration of the common practice of immediate return to play following non-loss-of-consciousness head injuries. Results on concussion frequency in ten models of football helmets indicated a significantly lower than expected frequency in the Riddell M155 and a significantly higher frequency in the Bike Air Power. All other models performed within expectations. This study demonstrates the need for monitoring on-the-field performance of football helmets through continuing epidemiological studies to supplement laboratory test data, which cannot duplicate all the factors involved in actual helmet performance.

Journal Article↗

PubMed1991

Interpretive criteria used to report western blot results for HIV-1-antibody testing--United States.

The Association of State and Territorial Public Health Laboratory Directors (ASTPHLD), CDC, and other organizations (e.g., American Red Cross [ARC] and Consortium for Retrovirus Serology Standardization [CRSS]) have recommended for antibody testing to human immunodeficiency virus type 1 (HIV-1) that duplicate repeat reactive enzyme immunoassay (EIA) screening results be confirmed by a supplemental test. This report examines the variation in Western blot (WB) interpretive criteria reported by laboratories enrolled in CDC's Model Performance Evaluation Program (MPEP) for HIV-1-antibody testing.

Blotting, Western↗

PubMed1983

Correlation between chromatin morphology as derived by digital image analysis and autoradiographic labeling pattern.

In order to interpret the Feulgen-dependent chromatin morphology on a functional basis, we performed model experiments in which labeling with 14C-thymidine and 14C-uridine was used as a functional parameter. Using a relocation facility, information on either DNA or RNA, labeling intensity of a cell was added to the parameters of image analysis by measuring the same cell by scanning photometry after Feulgen staining. The Feulgen-stained nuclei were interactively sampled and automatically segmented. Most of the textural information was gained from a flat texture image obtained by subtracting the original image from a median-filtered image. In addition to the autoradiographic features, visually recognizable differences in nuclear morphology, such as the number of nucleoli and the level of condensed (inactive) and diffuse (active) regions of the chromatin, were also correlated with textural parameters. Using the supervised cluster analysis method, an attempt was made to establish a correlation between visual nuclear morphology and autoradiographic labeling intensity that improved the functional understanding of the Feulgen features. Our results further clarify the supramolecular chromatin structure and its dynamics during specific transitions in the cell cycle, namely the G0-G1, G1-S and S-G2 transitions; this information may become useful in diagnostic procedures.

Animals↗

PubMed1980

[Lysolecithin and stress ulcers in rats].

The effect of lysolecithin on gastric mucosa in rats has been investigated using a new operative model. Ten rats underwent sham-laparotomy. In 4 other groups, each of 10 animals, the rats underwent pyloro-jejunostomy and Roux-en-Y anastomosis. 9 of 10 rats operated upon in this way, and given a solution of lysolecithin to drink before administration of restraint stress, produced stress ulcers. However, only 3 of 10 animals given Ringer-solution produced minor mucosal defects. Lysolecithin not combined with stress had no noteworthy deleterious effect on gastric mucosa either in sham-operated rats or in those with our operation model. Thus, lysolecithin combined with stress in our model performed an important function in the pathogenesis of stress lesions. Lysolecithin is produced in considerable quantities during fat metabolism in the intestine, and may be regurgitated together with duodenal contents into the stomach.

Animals↗

PubMed1995

Regional medical information network using optical memory cards and integrated services for digital network.

Since 1986, we have been developing a regional health and welfare system using optical memory cards. We have expanded the system and performed model experiments and evaluations this time. There are approximately 3000 card-holders and 23 card-reader terminals in use. They cover 50 percent of the medical facilities in the city of Isehara. Two medical clinics within neighboring cities have joined our project. Standard Deviation Index (SDI) has been introduced to standardize the numeric results of examinations. The terminals are connected with Integrated Services for Digital Network (ISDN) allowing remote access to the optical memory cards. This enhanced connectivity has allowed greater cooperation in delivering quality medical services.

Aged↗

PubMed1998

Impact of quality control on accuracy in enzyme immunoassay testing for human immunodeficiency virus type 1 antibodies.

OBJECTIVE: To assess use of quality control (QC) material, supplemental to internal kit controls (calibrators), as protection against errors in enzyme immunoassay testing for human immunodeficiency virus type 1 antibodies. DESIGN: From August 1994 to January 1996, enzyme immunoassay testing accuracy was assessed for laboratories participating in the Centers for Disease Control and Prevention Model Performance Evaluation Program that provided information regarding their use of QC material. Error rates were examined for human immunodeficiency virus type 1 antibody-negative, strongly positive, and weakly positive samples. RESULTS: The overall error rate with QC (2.20%) was significantly (P = .0023) lower than the error rate without QC (2.90%). With QC use there was a significant reduction in the relative risk of error for negative (P = .014) and weakly positive (P = .0067) samples. After multivariate analysis, use of QC lowered overall error rate by 29% (P = .0009). Laboratories not using QC were at increased risk of systematic error. Following the Clinical Laboratory Improvement Amendments of 1988 guidelines for QC material was relatively more protective against error than lower frequencies/number of levels. CONCLUSIONS: Using QC protected against errors in enzyme immunoassay testing for human immunodeficiency virus type 1 antibodies. Two levels of QC should be used with each run as mandated by the Clinical Laboratory Improvement Amendments of 1988.

Clinical Laboratory Techniques↗

PubMed1998

Quantification of cocontraction in spastic cerebral palsy.

Antagonist cocontraction was hypothesized to limit net moment production in children with spastic diplegic cerebral palsy (CP). A second hypothesis was that concontraction would vary with joint angle. To test these hypotheses, surface EMG activity and moment data from the quadriceps and hamstrings muscle groups were obtained from children with CP and compared with normally developing children during isometric flexion and extension exertions. A biomechanical model was developed to predict individual moments produced by the agonist and antagonist muscle groups. Concontraction was defined as the percentage of the net moment that was negated by the antagonist moment. The model performed well in predicting the measured moment as illustrated by high R2 correlation coefficients and low prediction errors. The mean maximum moment produced was greater in normally developing children than children with CP in both flexion and extension. Antagonist cocontraction during extension was greater in children with CP (12.2 +/- 14.4%) than in normally developing children (4.9 +/- 3.8%), implying that antagonist cocontraction is one explanation for the observed extension weakness in children with CP. However, during flexion, cocontraction was not significantly different between the two groups. Cocontraction differed significantly with joint angle in both groups during flexion and in the normally developing children during extension. Although quantifying coactivation based on EMG activity alone produced similar results, it underestimated the effect of the antagonist. The quantification of cocontraction has potential applications for characterizing spastic muscle dysfunction and thereby improving clinical outcomes in children with CP.

Adolescent↗

PubMed2004

Performance of 3D-database molecular docking studies into homology models.

The performance of docking studies into protein active sites constructed by homology model building was investigated using CDK2 and factor VIIa screening data sets. When the sequence identity between model and template near the binding site area is greater than approximately 50%, roughly 5 times more active compounds are identified than would be found randomly. This performance is comparable to docking to crystal structures.

Binding Sites↗

PubMed2005

Myosin heavy chain isoform expression and in vivo isometric performance: a regression model.

This investigation estimated the amount of variance in voluntary in vivo muscle performance that can be explained by relative myosin heavy chain (MHC) isoform expression. The role of the relative expression of these proteins in relation to in vitro force and velocity performance is well understood, but the in vivo model is less clear. Twenty-two men and women (mean +/- SD age, 27 +/- 6 years) performed isometric knee extensor actions in which peak force and rate of force development (RFD) were measured. The results of regression analysis showed that the inclusion of MHC IIb explained a significant (19.9%, p < 0.05) amount of variance in relative peak force (adjusted for muscle mass) and 14.1% of the variance in the first half of the rise phase of the force-time curve (RFD(0-50%)) (p < 0.1). The addition of MHC I into this model explained a significant (p < 0.05) amount of variance above that accounted for by MHC IIb in RFD (45.4%), RFD(0-50%) (50.8%), and RFD(50-100%) (second half of the rise phase of the force-time curve) (37.4%). Since the percentage of MHC IIb is reduced rather quickly with training, these data suggest that peak force may also be affected quickly by training. The percentage of MHC I has a longer course for change with training; therefore, it may be inferred that the greatest changes in RFD variables will likely occur during a longer course.

Adult↗

PubMed2004

Modelling the biological performance of a side-stream membrane bioreactor using ASM1.

Membrane bioreactors (MBRs) are attracting global interest but the mathematical modeling of the biological performance of MBRs remains very limited. This study focuses on the modelling of a side-stream MBR system using Activated Sludge Model No. 1 (ASM1), and comparing the results with the modelling of traditional activated sludge processes. ASM1 parameters relevant for the long-term biological behaviour in MBR systems were calibrated (i.e. Y(H) = 0.72gCOD/gCOD, Y(A) = 0.25gCOD/gN, b(H) = 0.25 d(-1), b(A) = 0.080 d(-1) and f(P) = 0.06), and generally agreed with the parameters in traditional activated sludge processes, with the exception that a higher autotrophic biomass decay rate was observed in the MBR. A sensitivity analysis for steady state operation and DO dynamics suggested that the biological performance of the MBR system (the sludge concentration, effluent quality and the DO dynamics) are very sensitive to the parameters(i.e. Y(H), Y(A), b(H), b(A), micro(maxH) and micro(maxA)), and influent wastewater components(X(I), S(S), X(S), S(NH)).

Biomass↗

PubMed1999

A structural model of achievement motives, performance approach and avoidance goals, and performance among Norwegian olympic athletes.

A structural model of achievement motives, performance approach and avoidance goals, and performance was applied and tested among 136 Norwegian Olympic level athletes. Achievement motives, competitive behavior over time, performance approach goal-clarity, and performance-avoidance goals were assessed, and elite performance observed. Analysis indicated that the motive to achieve success is positively correlated with competitive behavior over time (a long-term goal), whereas the motive to avoid failure is positively associated with performance avoidance goals. Both long-term competitive behavior goals and performance approach goal-clarity were positively correlated with elite performance whereas the performance-avoidance goal was negatively correlated with performance. When the proximal influences of goals are controlled, the achievement motives are not significantly related to performance. In this structural model, motives and goals shared 32% of the variance with the performance measure, whereas a more complicated model including goals, sex, and a triple interaction of sex and motives shared 42% of the variance with the performance measure.

Achievement↗

PubMed2004

Transformational leadership: relations to the five-factor model and team performance in typical and maximum contexts.

This study examined the 5-factor model of personality, transformational leadership, and team performance under conditions similar to typical and maximum performance contexts. Data were collected from 39 combat teams from an Asian military sample (N = 276). Results found that neuroticism and agreeableness were negatively related to transformational leadership ratings. Team performance ratings correlated at only.18 across the typical and maximum contexts. Furthermore, transformational leadership related more strongly to team performance in the maximum rather than the typical context. Finally, transformational leadership fully mediated the relationship between leader personality and team performance in the maximum context but only partially mediated the relationship between leader personality and team performance in the typical context. The Discussion section focuses on how these findings, although interesting, need to be replicated with different designs, contexts, and measures.

Adolescent↗

PubMed2002

The quantitative evaluation of functional neuroimaging experiments: mutual information learning curves.

Learning curves are presented as an unbiased means for evaluating the performance of models for neuroimaging data analysis. The learning curve measures the predictive performance in terms of the generalization or prediction error as a function of the number of independent examples (e.g., subjects) used to determine the parameters in the model. Cross-validation resampling is used to obtain unbiased estimates of a generic multivariate Gaussian classifier, for training set sizes from 2 to 16 subjects. We apply the framework to four different activation experiments, in this case [(15)O]water data sets, although the framework is equally valid for multisubject fMRI studies. We demonstrate how the prediction error can be expressed as the mutual information between the scan and the scan label, measured in units of bits. The mutual information learning curve can be used to evaluate the impact of different methodological choices, e.g., classification label schemes, preprocessing choices. Another application for the learning curve is to examine the model performance using bias/variance considerations enabling the researcher to determine if the model performance is limited by statistical bias or variance. We furthermore present the sensitivity map as a general method for extracting activation maps from statistical models within the probabilistic framework and illustrate relationships between mutual information and pattern reproducibility as derived in the NPAIRS framework described in a companion paper.

Adult↗

PubMed2005

Effect of patient location on the performance of clinical models to predict pulmonary embolism.

INTRODUCTION: Current clinical likelihood models for predicting pulmonary embolism (PE) are used to categorize outpatients into low, intermediate and high clinical pre-test likelihood of PE. Since these clinical prediction rules were developed using outpatients it is not known if they can be applied universally to both inpatients and outpatients with suspected PE. Thus, the purpose of this study was to determine the effect of patient location on the performance of clinical models to predict PE. MATERIALS AND METHODS: Two clinical models (Wells and Wicki) were applied to data from the multi-centered PIOPED study. The Wells score was applied to 1359 patients and the Wicki score was applied to 998 patients. 361 patients (27%) from the PIOPED study did not have arterial gas measurement and were excluded from the Wicki score patient group. Patients were stratified by their location at the time of entry into the PIOPED study as follows: outpatient/emergency, surgical ward, medicine/coronary care unit or intensive care unit. The diagnostic performance of the two clinical models was applied to the various patient locations and the performance was evaluated using the area under a fitted receiver operating characteristic curve (AUC). RESULTS: The prevalence of PE in the three clinical probability categories were similar for the two scoring methods. Both clinical models yielded the lowest diagnostic performance in patients referred from surgical wards. The AUC for both clinical prediction rules decreased significantly when applied to inpatients in comparison to outpatients. CONCLUSIONS: Current clinical prediction rules for determining the pre-test likelihood of PE yielded different diagnostic performances depending upon patient location. The performance of the clinical prediction rules decreased significantly when applied to inpatients. In particular, the rules performed least well when applied to patients referred from surgical wards suggesting these rules should not be used in this patient group. As expected the clinical prediction rules performed best in outpatients with the optimum diagnostic performance in patients referred from emergency and outpatient wards.

Adult↗

PubMed2001

Multicomponent simulation of wastewater-derived nitrogen and carbon in shallow unconfined aquifers. I. Model formulation and performance.

One of the most common methods to dispose of domestic wastewater involves the release of septic effluent from drains located in the unsaturated zone. Nitrogen from such systems is currently of concern because of nitrate contamination of drinking water supplies and eutrophication of coastal waters. The objectives of this study are to develop and assess the performance of a mechanistic flow and reactive transport model which couples the most relevant physical, geochemical and biochemical processes involved in wastewater plume evolution in sandy aquifers. The numerical model solves for variably saturated groundwater flow and reactive transport of multiple carbon- and nitrogen-containing species in a three-dimensional porous medium. The reactive transport equations are solved using the Strang splitting method which is shown to be accurate for Monod and first- and second-order kinetic reactions, and two to four times more efficient than sequential iterative splitting. The reaction system is formulated as a fully kinetic chemistry problem, which allows for the use of several special-purpose ordinary differential equation (ODE) solvers. For reaction systems containing both fast and slow kinetic reactions, such as the combined nitrogen-carbon system, it is found that a specialized stiff explicit solver fails to obtain a solution. An implicit solver is more robust and its computational performance is improved by scaling of the fastest reaction rates. The model is used to simulate wastewater migration in a 1-m-long unsaturated column and the results show significant oxidation of dissolved organic carbon (DOC), the generation of nitrate by nitrification, and a slight decrease in pH.

Fresh Water↗