PL
 |
EN
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 39

Liczba wyników na stronie
first rewind previous Strona / 2 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 2 next fast forward last
1
Content available Impact of modification with cetylpyridinium chloride – a potential cariogenic microflora inhibitor, on selected physical-mechanical properties of the water-activated glass-ionomer
Kupka T., Nowak J., Szczesio A., Kopacz K., Fronczek-Wojciechowska M., Sokolowski J.
Acta of Bioengineering and Biomechanics
|
2018
|
Vol. 20, no. 3
19--24
EN
Teeth caries is one of predominant civilization diseases. Dental fillings with antimicrobial addition might allow prevention of secondary caries. The purpose of this study was to evaluate hardness and tensile strength of cetylpyridinium chloride modified water activated glass-ionomer cement. Methods: Samples with diameter of 6 mm and height of 3 mm made of water-activated glass-ionomer cement were control group (0.0%). Test groups were series of samples of the same dimensions, with addition of cetylpyridinium chloride antibacterial in concentrations of 0.5, 1.0, 1.5 and 2.0%. Two subgroups were prepared in each group to determine Vickers Hardness and Diametral Tensile Strength after 1 and 24 hours of sample storage in distilled water. Results: During hardness studies, no strong effect of antibacterial concentration on hardness of samples was observed. Higher hardness values after 24 hours were demonstrated for all groups, compared to the samples tested after 1 hour. The exception was the group with the addition of 1% cetylpyridinium chloride, in which no statistically significant differences were observed. Diametral Tensile Strength values for samples tested after 1 hour decreased with increasing antibacterial concentration. A similar relationship was noticed for samples tested after 24 hours. No statistically significant differences were found between test samples after 1 or 24 hours. Conclusions: There was no significant effect of cetylpyridinium chloride concentration on the hardness of the samples that significantly increased during the study. With the increase in antibacterial concentration a decrease in diametral tensile strength value was observed, but these values did not change over time.
2
Content available remote Wpływ dioctanowej i diglukonianowej soli chlorheksydyny na właściwości wytrzymałościowe cementu szklano-polialkenowego aktywowanego wodą
Kupka T., Nowak J., Szczesio A., Kopacz K., Fronczek-Wojciechowska M., Sokołowski J.
Przemysł Chemiczny
|
2017
|
T. 96, nr 8
1756--1758
PL
Sól dioctanową chlorheksydyny i roztwór soli diglukonianowej chlorheksydyny dodano do cementu szklano-polialkenowego i oznaczono jego twardość oraz wytrzymałość na rozciąganie średnicowe. Wykazano, że dodatek soli chlorheksydyny do cementu poprawiał jego twardość w zależności od stężenia i czasu, a dodatek czynników przeciwdrobnoustrojowych nie powodował wyraźnego obniżenia wytrzymałości na rozciąganie średnicowe. Dodatek soli dioctanowej w mniejszym stopniu wpływał na zmiany właściwości fizyko-mechanicznych cementu w czasie niż modyfikacja solą diglukonianową. Wskazano na ewentualną możliwość zastosowania dioctanu chlorheksydyny jako modyfikatora cementu szklano-polialkenowego, nie wpływającego znacząco na jego wytrzymałość, a zapewniającego potencjalną ochronę przed próchnicotwórczym działaniem bakterii.
EN
Chlorhexidine diacetate salt powder (CHA) and chlorhexidine digluconate salt fluid (CHG) were sep. incorporated into a H₂O-activated glass-polyalkenoate cement compd. Vickers hardness and diam. tensile strength were detd. The addn. of CHA or CHG into the cement did not result in any significant change in its properties. The CHA was recommended as the cement modifier ensuring potential tooth protection from cariogenic bacteria.
3
Content available remote Evaluating the fetal heart rate baseline estimation algorithms by their influence on detection of clinically important patterns
Jezewski J., Horoba K., Roj D., Wrobel J., Kupka T., Matonia A.
Biocybernetics and Biomedical Engineering
|
2016
|
Vol. 36, no. 4
562--573
EN
A correctly estimated component of fetal heart rate signal (FHR) – so called baseline – is a precondition for proper recognition of acceleration and deceleration patterns. A number of various algorithms for estimating the FHR baseline was proposed so far. However, there is no reference standard enabling their objective evaluation, and thus no methodology of comparing the different algorithms still exists. In this paper we propose a method for evaluation of automatically determined baseline in reference to a set of experts, based on ten separate groups of signals comprising typical variability patterns observed in the fetal heart rate. As it was proposed earlier [1], the given algorithm is evaluated based on the characteristic patterns detected using the obtained baseline, instead of direct analysis of the baseline shape. For the purpose of quantitative assessment of the estimated baseline a new synthetic inconsistency coefficient was applied. The proposed methodology enabled to evaluate eleven well-known algorithms. We believe that the method will be a valuable tool for assessment of the existing algorithms, as well as for developing the new ones.
4
Content available remote Automated detection of uterine contractions in tocography signals – Comparison of algorithms
Horoba K., Wrobel J., Jezewski J., Kupka T., Roj D., Jezewski M.
Biocybernetics and Biomedical Engineering
|
2016
|
Vol. 36, no. 4
610--618
EN
Monitoring of uterine contractile activity enables to control the progress of labor. Automated detection of contractions is an integral part of the signal analysis implemented in computer- aided fetal surveillance system. Comparison of four algorithms for automated detection of uterine contractions in the signal of uterine mechanical activity is presented. Three algorithms are based generally on analysis of the frequency distribution of signal values. The fourth method relies on analyzing the rate of changes of the uterine activity signal. The reference data in form of beginning and end of contraction episodes were provided by human experts. Obtained results show that all algorithms were capable to detect above 91% reference contractions, and less than 7% of recognized patterns were false. Two algorithms can be distinguished as providing a higher performance expressed by the sensitivity of 95% and the positive predictive value of 97%. Such results could be obtained by optimization of contraction validation criteria.
5
Content available Efficiency of automated detection of uterine contraction using tocography
Horoba K., Wrobel J., Jezewski J., Kupka T., Czabanski R., Roj D., Jezewski M.
Journal of Medical Informatics & Technologies
|
2015
|
Vol. 24
207--214
EN
Monitoring of uterine contractile activity enables to control the progress of labour. Automated detection of contractions is to be an integral part of the signal analysis implemented in computer aided fetal surveillance system. Evaluation of efficiency of three algorithms for automated detection of uterine contractions in the signal of uterine mechanical activity is presented. These algorithms are based generally on analysis of the frequency distribution of signal values. The reference data in form of beginning and end of contraction episodes were obtained from human expert. Obtained results showed high efficiency of the algorithms tested where the best one ensured the sensitivity and positive predictive value equal to 92.2 and 97.2, respectively.
6
Content available A novel approach to comparison of the fetal heart rate baseline estimation algorithms
Jezewski J., Horoba K., Roj D., Wrobel J., Kupka T., Matonia A.
Journal of Medical Informatics & Technologies
|
2015
|
Vol. 24
231--238
EN
A number of algorithms for estimating the so called fetal heart rate baseline was proposed so far. However, there is no reference pattern enabling their objective evaluation, and thus no methodology of comparing the competing algorithms still exists. In this paper we propose a method for evaluation of automatically determined baseline in reference to a group of experts, basing on ten separate groups of signals comprising typical patterns observed in the fetal heart rate. For the purpose of quantitative assessment of the estimated baseline a new synthetic inconsistency coefficient is presented. The proposed methodology was applied to evaluate ten well-known algorithms. We believe that the method will be a valuable tool for assessment of the existing algorithms, as well as for developing new ones.
7
Content available The influence of signal loss episodes on fetal heart rate variability measures
Wróbel J., Roj D., Jeżewski J., Horoba K., Kupka T., Jeżewski M.
Journal of Medical Informatics & Technologies
|
2014
|
Vol. 23
35--42
EN
The most important features indicating appropriate fetal development are the measures of instantaneous variability of a fetal heart rate (FHR), describing fluctuations of the beat-to-beat heart intervals. The most popular method for the FHR acquisition is the Doppler ultrasound technique. However, it is very sensitive to various motion artifacts distorting the signal being acquired. The aim of our work was to evaluate the influence of signal loss episodes on the parameters quantitatively describing the instantaneous variability of the FHR. For this purpose we artificially inserted signal loss episodes to the recordings, in different patterns and percentage, in accordance with the real characteristics of the signal loss segments. We particularly would like to answer the question if the signals with significant amount of signal loss can be reliably evaluated by means of instantaneous variability measures, and which of these measures (numerical indices) are more robust to the missing values.
8
Content available Automated detection of fetal movements in Doppler ultrasound signals versus maternal perception
Wróbel J., Kupka T., Horoba K., Matonia A., Roj D., Jeżewski J.
Journal of Medical Informatics & Technologies
|
2014
|
Vol. 23
43--50
EN
Analysis of movement activity is important since it enables detection of nonreactive fetal heart rate recordings. The aim of the study was to develop an algorithm for automated detection of the fetal movement activity (actogram), based on analysis of the Doppler ultrasound signal, and to evaluate a reliability of the actogram as a source of information about the fetal movements. Bandpass filtering (20-80 Hz) was used to separate the actogram signal describing the fetal movement activity. Simultaneously there were recorded the markers of fetal movements perceived by mother, being the reference information. For the determination of the binary actogram, the authors proposed an algorithm in which the classification threshold was estimated at the beginning of each recording and was adaptively modified during its duration. The algorithm ensured detection of up to 89% of movement episodes corresponding to movements perceived by mother. At the same time almost as high number of episodes not related to the reference information was recognized. Obtained results revealed that the automated analysis of fetal movements is characterized by much higher sensitivity of movement episode detection compared to the maternal perception.
9
Content available Od modelowania molekularnego po nanotechnologię i czystą energię
Kupka T., Stachów M., Nieradka M., Radula-Janik K., Stobiński L., Kaminsky W.
Chemik
|
2014
|
Vol. 68, nr 4
288--295
PL
W dobie ogromnego rozwoju przemysłu i gospodarki oraz katastroficznego widma wyczerpania się surowców kopalnych jako źródeł energii, istotne jest znalezienie alternatywnych źródeł pozyskiwania oraz magazynowania energii. Nanorurki węglowe, grafeny i fulereny stały się najbardziej obiecującymi materiałami XXI w. Ponadto, przewodzące materiały polimerowe mogą być wykorzystane do konwersji energii słonecznej na energię elektryczną. Modelowanie molekularne pozwala na dokładne przewidywanie właściwości fizyko-chemicznych związków chemicznych i materiałów o potencjalnym zastosowaniu w nowoczesnej energetyce (m.in. karbazoli, nanorurek węglowych, grafenów i fulerenów). W pracy przedstawiono zastosowanie modelowania molekularnego do przewidywania parametrów strukturalnych spektroskopowych.
EN
In the times of worldwide energetic crisis and catastrophic threat of depletion of fossil resources as energy source, it is important to find new alternative energy sources and methods for energy storage. Carbon nanotubes, graphenes and fullerenes have become most promising materials of 21st century. Moreover, conductive polymer materials might be use for conversion of solar energy to electricity. Molecular modelling allows to precisely predict physical and chemical properties of chemical compounds and materials that might be potentially applied in modern power industry (i.a. carbazoles, carbon nanotubes, graphenes and fullerenes). The article presents examples of molecular modelling application for prediction of spectroscopic parameters.
10
Content available Reconstruction of FHR series recorded via ultrasound - method validation using abdominal fetal electrocardiography
Kupka T., Horoba K., Roj D., Matonia A., Czabanski R., Jezewski M.
Journal of Medical Informatics & Technologies
|
2013
|
Vol. 22
135--141
EN
Analysis of variability of the fetal heart rate (FHR) is very important for fetal wellbeing assessment. The beat-to-beat variability is described quantitatively by the indices originated from invasive fetal electrocardiography which provides the FHR signal in a form of time event series. Nowadays, monitoring instrumentation is based on Doppler ultrasound technology. The fetal monitors provide the output signal in a form of evenly spaced measurements. The goal of this work is to present a new method for the FHR signal processing, which enables extraction of time series of consecutive heartbeat intervals from the evenly repeated values. The proposed correction algorithm enables recognition and removal of the duplicated measurements. Reliable evaluation of the algorithm requires the reference event series, thus the FHR signals were obtained from abdominal fetal electrocardiograms to be used in this research study.
11
Content available Detection of human fall episodes based on coordinates of body tags and numerical differentiation
Momot M., Momot A., Nowak G., Seredynski R., Jezewski J., Kupka T.
Journal of Medical Informatics & Technologies
|
2012
|
Vol. 21
11--17
EN
This paper presents a new method for detection of changes in alignment of the human body, particularly the fall, on the basis of signals acquired from the position sensors placed on the body of the monitored person. The sensors are located on the cuffs, waist and chest. Transformation of data sequence collected from sensors is proposed in order to best distinguish between the collapse from the normal movement. It is based on nonlinear combination of the first two derivatives of the signals being read. Because data from the sensors is sent asynchronously, a numerical algorithm for unevenly sampled data differentiation is proposed. Derivative values are calculated in equidistant nodes through differentiation of a polynomial, which is adjusted by minimizing the mean square error. The developed method can be used in home care telemedicine systems, where it is necessary to long term monitor of multiple vital parameters of people under care.
12
Content available Comparison of instantaneous fetal heart rate extracted from abdominal and direct fetal electrocardiograms
Matonia A., Kupka T., Jezewski J., Momot A., Jeżewski M., Bernys M.
Journal of Medical Informatics & Technologies
|
2012
|
Vol. 19
101--107
EN
This work is an attempt to assess the reliability of indirect abdominal electrocardiography as an alternative technique of fetal monitoring. As a reference signal we used the simultaneously acquired direct fetal electrocardiogram. Each recording consisted of four signals acquired from maternal abdomen and the reference signal acquired directly from fetal head. The first stage of our study concerned the signal loss episodes. In order to reduce the influence of incorrectly detected R-waves, some certain validation rules were applied. In the second stage, the corresponding intervals determined on basis of both acquisition methods were matched and the accuracy of fetal heart rate measurement was evaluated. Although the accuracy of abdominal electrocardiography turned out to be slightly lower than reported for ultrasound method, it still has some unique features deciding of its prevalence in a certain circumstances.
13
Content available An approach to unsupervised classification
Przybyła T., Pander T., Horoba K., Kupka T., Matonia A.
Journal of Medical Informatics & Technologies
|
2011
|
Vol. 17
105--111
EN
Classification methods can be divided into supervised and unsupervised methods. The supervised classifier requires a training set for the classifier parameter estimation. In the case of absence of a training set, the popular classifiers (e.g. K-Nearest Neighbors) can not be used. The clustering methods are considered as unsupervised classification methods. This paper presents an idea of the unsupervised classification with the popular classifiers. The fuzzy clustering method is used to create a learning set. The learning set includes only these patterns that are the best representative of each class in the input dataset. The numerical experiment uses an artificial dataset as well as the medical datasets (PIMA, Wisconsin Breast Cancer) and illustrates the usefulness of the proposed method.
14
Content available Improving the periodicity measurement in fetal heart activity signal
Roj D., Wróbel J., Horoba K., Przybyła T., Kupka T.
Journal of Medical Informatics & Technologies
|
2010
|
Vol. 16
19--26
EN
In this paper we discussed the influence of preliminary processing of the ultrasound Doppler signal on accuracy of the fetal heart rate estimation as well as on reliability of the FHR instantaneous variability assessment. We attempted to develop an optimal processing channel of US Doppler signal in order to measure the periodicity of fetal heart activity with accuracy as close as possible to that ensured by FECG. The FHR values determined from the US signal were compared to the reference data obtained from direct FECG. In a final evaluation we used the parameters describing the FHR variability as the clinically important signal features being the most sensitive to any periodicity inaccuracy. The results proved that an application of proposed algorithms improves the accuracy of interval measurements and FHR instantaneous variability assessment in relation to the new-generation fetal monitors.
15
Content available Evaluation of predictive capabilities of quantitative cardiotocographic signal features
Czabański R., Jeżewski M., Roj D., Szaszkowski Z., Kupka T., Wróbel J.
Journal of Medical Informatics & Technologies
|
2010
|
Vol. 16
11--17
EN
Cardiotocography (CTG) is the main method of assessment of the fetal state during pregnancy and labour used in clinical practice. It is based on quantitative analysis of fetal heart rate, fetal movements and uterine contractions signals. The evaluation of the CTG signals can be made using criteria recommended by International Federation of Obstetrics and Gynecology. Nevertheless, the diagnosis verification is possible only after the delivery on the basis of newborn assessment. In the proposed work we evaluated the capacity of quantitative analysis of CTG traces in predicting fetal outcome. The relationship between CTG signal features and attributes of fetal outcome was assessed on the basis of ROC curves analysis. The obtained results indicate the adequate predictive capabilities of the selected CTG features especially for fetal outcome assessed with Apgar score and suggest the necessity of applying the criteria for the CTG traces evaluation that are related to the gestational age. Our study also shows the value of the CTG monitoring as a screening procedure providing appropriate confirmation of fetal wellbeing.
16
Content available State-space averaging for maternal ECG suppression
Kotas M., Jeżewski J., Kupka T., Matonia A.
Journal of Medical Informatics & Technologies
|
2009
|
Vol. 13
194--200
EN
In this paper a new method of maternal electrocardiogram suppression for fetal component extraction from one-channel maternal abdominal bioelectric signals is proposed. The method performs maternal ECG estimation by application of state-space averaging. The estimated signal is subtracted from the original one and this way suppressed. The method parameters allow us to balance between the precision of maternal ECG suppression and the necessity not to attenuate the fetal QRS complexes. A small database of the maternal abdominal bioelectric signals is used to investigate the developed system for fetal heart rate determination. The final assessment is based on the detection performance index. It is shown that by proper choice of the parameters we can tune the system so that it is more effective than the classical approach based on template subtraction.
17
Content available The prediction of the low fetal birth weight based on quantitative description of cardiotocographic signals
Czabański R., Jeżewski M., Wróbel J., Kupka T., Łęski J., Jeżewski J.
Journal of Medical Informatics & Technologies
|
2008
|
Vol. 12
97--102
EN
Cardiotocography (CTG) is a routine method of fetal condition assessment used in modern obstetrics. It is a biophysical method based on simultaneous recording and analysis of activity of fetal heart, fetal movements and maternal uterine contractions. The fetal condition is diagnosed on the basis of printed CTG trace evaluation. The correct interpretation of CTG traces from a bedside monitor is very difficult even for experienced clinicians. Therefore, computerized fetal monitoring systems are used to yield the quantitative description of the signal. However, the effective methods, aiming to support the conclusion generation, are still being searched. One of the most important features defining the state of fetal outcome is the weight of the newborn. The presented work describes an application of the Artificial Neural Network Based on Logical Interpretation of fuzzy if-then Rules (ANBLIR) to evaluate the risk of the low birth weight using a set of parameters quantitatively describing the CTG traces. The obtained results confirm that the neuro-fuzzy based CTG classification methods are very efficient for the prediction of the fetal outcome.
18
Content available Telemedical system for home fetal monitoring with online analysis of bioelectricalabdominal signals
Wróbel J., Jeżewski J., Matonia A., Kupka T., Gacek A., Roj D.
Journal of Medical Informatics & Technologies
|
2008
|
Vol. 12
91--95
EN
This paper presents some aspects of the on-line remote fetal monitoring system based on the GPRS data transmission service and WAN network. The remote signal recording instrumentation consists of bioelectrical signal recorder and tablet PC computer. The central surveillance system located in hospital has a capability of simultaneous monitoring of up to 24 patients, both remotely and within hospital. The system enables analysis, dynamic presentation and archiving of signals and medical data. The clinical interpretation is immediately available in hospital as well as at patient's home or attending doctor office.
19
Content available Separation of abdominal fetal electrocardiograms in twin pregnancy
Kotas M., Jeżewski J., Matonia A., Kupka T.
Journal of Medical Informatics & Technologies
|
2008
|
Vol. 12
83--89
EN
A combined application of independent component analysis and projective filtering of the time-aligned ECG beats is proposed to solve the problem of fetal ECG extraction from multi-channel maternal abdominal electric signals. The developed method is employed to process the four-channel abdominal signals recorded during twin pregnancy. The signals are complicated mixtures of the maternal ECG, the ECGs of the fetal twins and noise of other origin. The independent component analysis cannot separate the respective signals, but the proposed combination of the methods allows to suppress the maternal ECG and when the level of noise is low it leads to an effective separation of the twins' signals.
20
Content available remote Recognition of early symptoms of fetal distress with on-line analysis of bioelectrical signals from maternal abdomen
Gacek A., Matonia A., Jeżewski J., Kupka T.
Biocybernetics and Biomedical Engineering
|
2007
|
Vol. 27, no. 1-2
207-216
EN
Conventional fetal monitoring for recognition of fetal distress is based on ultrasound Doppler technique. The new approach proposed in this work relies on analysis of bioelectrical signals recorded from the maternal abdominal wall. Fetal electrocardiogram and uterine electrical signal are extracted from abdominal signals using advanced instrumentation and algorithms for signal processing. Evaluation of the fetal heart rate variability with an additional analysis of fetal electrocardiogram morphology is expected to ensure early detection of fetal hypoxia symptoms and, finally, an appropriate obstetrical intervention.
first rewind previous Strona / 2 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.