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At least 523 records · Page 29Linked to original sources
PubMed2001

Comparison of two software versions for assessment of body-composition analysis by DXA.

OBJECTIVE: To compare two software versions provided by Lunar CO: for assessment of body composition analysis by DXA. RESEARCH METHODS AND PROCEDURES: Soft-tissue phantoms for lean tissue (water) and fat tissue (methanol) were repeatedly scanned using DXA machines (DPX-L; Lunar CO., Madison, WI) and analyzed using software version 1.33 and the updated year 2000-compatible version 1.35. For the intersoftware comparison, the phantoms were scanned 10 times (each scan was analyzed once) with both software versions using all three scanning modes (slow, medium, and fast) for a total of 60 scans and analyses. For the intermachine comparison, the same phantoms were scanned three times (each scan was analyzed once) with a second machine from the same manufacturer using all three scanning modes and version 1.35 only. Percentage of fat was the variable of interest. RESULTS: For version 1.33, fat was 9.9 +/- 0.4%, 10.0 +/- 0.5%, and 11.0 +/- 0.5% (mean +/- SD) for the lean-tissue phantom and 50.8 +/- 0.3%, 50.9 +/- 0.5%, and 51.1 +/- 0.6% for the fat-tissue phantom using the slow, medium, and fast scanning modes, respectively. For version 1.35, the respective fat values were 9.8 +/- 0.7%, 9.9 +/- 0.4%, and 10.3 +/- 0.7%, and 50.6 +/- 0.5%, 50.9 +/- 0.6%, and 50.8 +/- 0.8%, respectively. For the lean-tissue phantom, the estimation of percentage of fat was significantly (p < 0.05) affected by scanning mode but not by software version. For the fat-tissue phantom, the estimation of percentage of fat was not affected by either scanning mode or software version. The use of version 1.35 did not effect intermachine variability. DISCUSSION: Versions 1.33 and 1.35 of the Lunar body composition software appear to be comparable. Soft-tissue phantoms, such as the ones described in this paper, may be useful in monitoring the reproducibility of body composition analyses within and between DXA machines, particularly in longitudinal studies.

Absorptiometry, Photon↗
PubMed1996

Initial experience of the ORATEL computerised information tools in general practice.

ORATEL (a telematic system for quality assurance indicators in oral health care) is a three-year project with the ultimate objective of improving the quality of oral health care through the use of appropriate computerised information systems. These tools are designed to promote quality assurance and quality of care development in oral health care by using common quality indicators/standards. ORATEL has developed three prototypes of computerised information systems: an interactive multimedia teach software on quality assurance in oral health care, ORATEL-TEACH; a proactive quality assurance support tool for real time use at the dental unit, ORATEL-PROACT; and an integrated set of modules for monitoring and self assessment at the clinical level and for the computerised reporting of aggregated data for evaluation at higher levels, ORATEL-REVAL. The initial experiences of using these tools was assessed during 1993 in general dental practice locations in Liverpool and clinics in for other European countries. Overall, the dentists were positive about the potential usefulness of the ORATEL tools but further improvements were considered necessary. Finding has been approved by the European Commission for further development under a new project called ORQUEST.

Computer Communication Networks↗
PubMed2005

Benchmark calculations of proton affinities and gas-phase basicities of molecules important in the study of biological phosphoryl transfer.

Benchmark calculations of proton affinities and gas-phase basicities of molecules most relevant to biological phosphoryl transfer reactions are presented and compared with available experimental results. The accuracy of proton affinity and gas-phase basicity results obtained from several multi-level model chemistries (CBS-QB3, G3B3, and G3MP2B3) and density-functional quantum models (PBE0, B1B95, and B3LYP) are assessed and compared. From these data, a set of empirical bond enthalpy, entropy, and free energy corrections are introduced that considerably improve the accuracy and predictive capability of the methods. These corrections are applied to the prediction of proton affinity and gas-phase basicity values of important biological phosphates and phosphoranes for which experimental data does not currently exist. Comparison is made with results from semiempirical quantum models that are commonly employed in hybrid quantum mechanical/molecular mechanical simulations. Data suggest that the design of improved semiempirical quantum models with increased accuracy for relative proton affinity values is necessary to obtain quantitative accuracy for phosphoryl transfer reactions in solution, enzymes, and ribozymes.

Algorithms↗
PubMed2000

Specialized spring design in segmented edgewise orthodontics: further verification of dedicated software.

A software program for use in the investigation of specialized springs used in the segmented arch technique has previously been developed and an example of its clinical application has been shown. The purpose of this study was to further assess the reliability of the software in 4 tests using T-loop springs. A numerical simulation of a determined experimental condition relative to a T-loop spring was carried out in each test. Numerical and experimental results were compared, and the precision of the analytical tool was assessed relative to a variety of parameters of the spring. Since the comparison between numerical and experimental results showed good agreement along the entire range of activation of the spring, the reliability of the software is sufficient for the clinical purposes of the segmented arch technique.

Computer Simulation↗
PubMed1998

Mathematical shape matching as a tool in tooth wear assessment--development and conduct.

The quantitative assessment of restoration and tooth wear usually requires fixed reference points from which measurements are made. In longitudinal patient follow-up the loss or erosion of such points may preclude measurement and an alternative approach is to seek regions of coincidence and conflict in digital models of before and after wear surfaces, with a continuous refinement of the parameters of the coordinate transformations, until the closest correspondence between them is found. A computer program has been written to implement the algorithm and assess the technique's capacity to find the match between surfaces both artificially generated and from tooth replicas recorded from patients at different epochs. The program was able to achieve the desired ends, demonstrating the utility of the technique in tooth wear assessment but identifying the need to refine the program further to enhance both its difference detection capabilities and level of automation. Examination of the theory and practical experience highlighted certain situations when user understanding is invaluable to ensure a satisfactory solution. This strengthened the investigators' resolve against reliance upon commercially based surface fitting programs whose basis may not be fully understood. Notwithstanding this surface matching is a powerful tool in the investigation of dental wear.

Algorithms↗
PubMed2001

Intermittent mode reversion to VOO of a dual chamber pacemaker model.

This report describes an asymptomatic patient with a DDDR pacemaker system (Inos Cls, Biotronik) that showed intermittent mode reversion to VOO and sometimes to VVI without a detectable source of electromagnetic interference and oversensing. Patients with this Biotronik model should be carefully assessed along with a surface ECG before placing the programming head.

Cardiac Pacing, Artificial↗
PubMed2002

Impaired detection of ventricular tachyarrhythmias by a rate-smoothing algorithm in dual-chamber implantable defibrillators: intradevice interactions.

INTRODUCTION: Rate smoothing is an algorithm initially designed to prevent rapid changes in pacemaker rates. In this study, we sought to determine the potential of the rate-smoothing mechanism in preventing detection of ventricular tachyarrhythmias. METHODS AND RESULTS: Clinical testing of rate smoothing was performed at the time of defibrillator arrhythmia induction in 16 patients with implantable defibrillators during 65 episodes of ventricular tachyarrhythmias. We also performed simulator-based testing to assess detection of ventricular tachycardia between 170 and 220 beats/min with systematic sequential change of rate-smoothing percent, AV delay, and maximal rate. During clinical testing of 54 ventricular fibrillation/polymorphic ventricular tachyarrhythmia episodes, there were no cases of nondetection and 3 episodes (5%) of minimally delayed detection. Of 10 monomorphic ventricular tachyarrhythmias, 6 had either delayed (2 cases) or absent (4 cases) detection. During simulator testing, complex interrelationships were demonstrated in AV delay, upper rate, and rate-smoothing percent in determining the severity of the effect on detection. Generally, long AV delay, higher upper rate, and smaller (more aggressive) rate smoothing were associated with increased risk of ventricular tachyarrhythmia underdetection. Importantly, use of parameters that impaired detection was always accompanied by a programmer warning message. CONCLUSION: Rate smoothing may result in delay or failure of ventricular tachycardia detection. It is important to consider warning messages when programming rate smoothing and to test for appropriate detection when rate smoothing is used despite warning messages.

Algorithms↗
PubMed2003

Feasibility and reliability of on-line automated microemboli detection after carotid endarterectomy. A transcranial Doppler study.

OBJECTIVES: recently, a new algorithm for transcranial Doppler (TCD) ultrasound detection of microembolic signals (MES) was developed. In the present study, we investigated its on-line performance in TCD monitoring after carotid endarterectomy (CEA) and assessed off-line its accuracy in detecting MES. MATERIALS AND METHODS: first, the feasibility of MES detection in TCD monitoring after CEA in a routine clinical setting was evaluated in 50 patients. Second, to test the reliability of the software a 2-h digital audio study tape was made and analysed by the algorithm and five human experts. The "gold standard" was defined as the agreement between human experts: a MES was considered to be present if at least three human observers agreed. RESULTS: TCD monitoring for emboli detection after CEA was well tolerated by the patients and could be performed reliably. In the study tape, the human gold standard detected 107 MES, with 93 MES having an intensity of > or =7 dB. The software detected 81 and 77 MES, respectively. Using the 7 dB intensity threshold, the software had no false positives and 16 false negatives. The kappa value between the human gold standard and the software was 0.91, the proportion of specific agreement was 0.83. CONCLUSIONS: the tested algorithm provides a reliable method for automated on-line microemboli detection after CEA. This makes monitoring of the effectiveness of antiplatelet agents in the prevention of stroke after CEA more practicable.

Algorithms↗
PubMed2000

Infection control training: evaluation of a computer-assisted learning package.

An evaluation of the training module of an interactive infection control computer-assisted learning (CAL) software program was carried out with ward-based nurses, third-year medical students and infection control personnel. All nursing staff, 87% of the medical students and all infection control staff found the programme easy and enjoyable to use. The module was accessed 3101 times on the hospital network in 18 months with usage settling to between 100-150 times per month. There was a higher level of use by night-duty and weekend staff. Medical students gained as much infection control knowledge from using the CAL package (increase in correct responses from 63.5% to 83.4%;P<0.0001) as they did from a formal lecture (increase in correct responses from 62.1% to 79.5%;P<0.0001). We conclude the training module which is accessible on the hospital wards and across the academic network, is a convenient and effective way for staff and students to gain a basic understanding in evidence-based infection control practices, at locations and times suitable for them.

Attitude of Health Personnel↗
PubMed2001

A computer-based method for calculation of orbital floor fractures from coronal computed tomography scans.

PURPOSE: A computer program recently developed for the calculation of the orbital floor and fracture areas from coronal computed tomography (CT) scans was used in a study to evaluate the accuracy and ability of this new method. MATERIAL AND METHODS: The size of orbital floors and fabricated fractures in 14 dried, anatomic specimens were measured in coronal CT scans by 3 independent observers. Based on this data set, the orbital floor and fracture regions were calculated with the newly developed computer program. These calculated regions were then compared with a direct measurement of the specimens that had been obtained by digital photography. The accuracy of the computer-based calculations was assessed using Lin's concordance correlation coefficient. RESULTS: The size of the orbital floor (mean +/- SD) was found to be 5.21 +/- 0.39 cm(2) by direct measurement of the specimens and 5.30 +/- 0.52 cm(2) by calculation with the computer program. The region of the fracture (mean +/- SD) was 1.05 +/- 0.64 cm(2) by direct measurement and 1.01 +/- 0.62 cm(2) by computer calculation. The between-method mean difference (direct measurement minus computer based calculation) was -0.09 cm(2) (or 1.7% of mean orbital floor region) for orbital floor region and 0.04 cm(2) (or 3.8% of mean fracture region) for fracture region. CONCLUSIONS: This accurate and time-saving method is practicable for determining the size and location of orbital floor fractures. This calculation program can be advantageously applied in the clinical management of blowout fractures of the orbit.

Algorithms↗
PubMed2006

[Quantification of pulmonary emphysema in multislice-CT using different software tools].

PURPOSE: The data records of thin-section MSCT of the lung with approx. 300 images are difficult to use in manual evaluation. A computer-assisted pre-diagnosis can help with reporting. Furthermore, post-processing techniques, for instance, for quantification of emphysema on the basis of three-dimensional anatomical information might be improved and the workflow might be further automated. MATERIALS AND METHODS: The results of 4 programs (Pulmo, Volume, YACTA and PulmoFUNC) for the quantitative analysis of emphysema (lung and emphysema volume, mean lung density and emphysema index) of 30 consecutive thin-section MSCT datasets with different emphysema severity levels were compared. The classification result of the YACTA program for different types of emphysema was also analyzed. RESULTS: Pulmo and Volume have a median operating time of 105 and 59 minutes respectively due to the necessity for extensive manual correction of the lung segmentation. The programs PulmoFUNC and YACTA, which are automated to a large extent, have a median runtime of 26 and 16 minutes, respectively. The evaluation with Pulmo and Volume using 2 different datasets resulted in implausible values. PulmoFUNC crashed with 2 other datasets in a reproducible manner. Only with YACTA could all graphic datasets be evaluated. The lung volume, emphysema volume, emphysema index and mean lung density determined by YACTA and PulmoFUNC are significantly larger than the corresponding values of Volume and Pulmo (differences: Volume: 119 cm(3)/65 cm(3)/1 %/17 HU, Pulmo: 60 cm(3)/96 cm(3)/1 %/37 HU). Classification of the emphysema type was in agreement with that of the radiologist in 26 panlobular cases, in 22 paraseptalen cases and in 15 centrilobular emphysema cases. CONCLUSION: The substantial expenditure of time obstructs the employment of quantitative emphysema analysis in the clinical routine. The results of YACTA and PulmoFUNC are affected by the dedicated exclusion of the tracheobronchial system. These fully automatic tools enable not only fast quantification without manual interaction, but also a reproducible measurement without user dependence.

Adolescent↗
PubMed2004

Error function attack of chaos synchronization based encryption schemes.

Different chaos synchronization based encryption schemes are reviewed and compared from the practical point of view. As an efficient cryptanalysis tool for chaos encryption, a proposal based on the error function attack is presented systematically and used to evaluate system security. We define a quantitative measure (quality factor) of the effective applicability of a chaos encryption scheme, which takes into account the security, the encryption speed, and the robustness against channel noise. A comparison is made of several encryption schemes and it is found that a scheme based on one-way coupled chaotic map lattices performs outstandingly well, as judged from quality factor.

Algorithms↗
PubMed2001

Quantitative analysis of apical root resorption by means of digital subtraction radiography.

OBJECTIVE: This study was performed to assess the diagnostic and quantifying ability of digital subtraction images for simulated apical root resorption, as well as to compare the diagnostic accuracy of conventional intraoral radiographs with digital subtraction images for this condition. STUDY DESIGN: Digital and intraoral radiographs of 10 sound maxillary central incisors and those with simulated apical root resorption were taken with varying horizontal and vertical angulations of the x-ray beam. Paired t tests were used to compare the lengths of the sound teeth on the images with their actual lengths, and the estimated amount of simulated apical root resorption was compared with the actual amount of tooth loss by means of Emago software. The diagnostic accuracy for detecting lesions was also evaluated on conventional intraoral radiographs and digital subtraction images through receiver operating characteristic (ROC) analysis. RESULTS: There were no statistically significant differences between the actual lengths and those measured on the reconstructed images of the sound teeth. The calculated amounts of apical root resorption showed no statistically significant differences in comparison with the actual amounts (P >.05). The diagnostic accuracy of the conventional intraoral radiographs in detecting the lesions was low (ROC area = 0.6446). CONCLUSION: A quantitative analysis of small amounts of apical root resorption can be performed by means of digital subtraction radiography.

Humans↗
PubMed1999

The year 2000 problem: hiccough or approaching Armageddon.

The complexity of information technology systems has increased to approximate that of biological organisms, with a similar unpredictability of behaviour. With several million lines of code, a modern computer operating system, still can only be compared in complexity to a bacterial genome. However, just as unpredictable mutations continuously arise in the 3000 million haploid base pairs of human code and cause much misery and disease, undiscovered errors lie buried in the accumulated machine code which make up our world. As in human genetics, the difficulty is often distinguishing the harmless polymorphisms from the dangerous or lethal mutations. Similarly there is uncertainty about the impact of errors in data-handling code, which make up the "Year 2000 Problem". Over the remaining months it is vital that critical systems are checked for year 2000 compliance so as to avoid potentially serious disruption.

Chronology as Topic↗
PubMed2003

Students' responses to the introduction of a digital laboratory guide in medical neuroscience.

This study investigated student acceptance of a digital laboratory guide in a medical neuroscience course. The guide was created in Macromedia Authorware 5.2 by transforming a text-based lab manual into a comprehensive multimedia program. Student attitudinal survey data indicated that the guide was used primarily as a study tool at home. Some 53% of students (primarily males) used the guide for independent study exclusively, while the remainder used it for both independent and group study; 87% of the class used the guide as a routine study tool rather than as a final review for examinations. Most students perceived that the guide increased their study efficiency and lab performance while decreasing their out-of-class study time in the lab. Female students were significantly more enthusiastic about the guide's impact on their study efficiency, lab performance and laboratory study time. Gender differences in student satisfaction with and use of instructional multimedia are discussed.

Attitude of Health Personnel↗