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PubMed2000

Towards automated Laue data processing: application to the choice of optimal X-ray spectrum.

Laue data reduction has now reached a level of sophistication that allows nearly automated processing to be performed. The software described enables complete reduction of the data with essentially no user intervention, making Laue processing almost as straightforward as monochromatic data processing. Interactive work is limited to the indexing of only one Laue pattern. More importantly, it is shown that the data quality is substantially enhanced when soft-limited predictions are used. Further improvement obtained by taking advantage of the structure-factor amplitudes from a known closely related structure is described. To determine the most suitable type of insertion device to be used for time-resolved Laue crystallography, the technique described was applied to Laue data sets collected from photoactive yellow protein under identical conditions but with three different insertion devices: a wiggler, a broad-bandpass undulator and a single-line undulator. Although the optimal choice may ultimately be dictated by sample parameters (such as mosaic spread) and by the type of experiment (repeatable or non-repeatable reactions), the results here show that the use of single-line undulators will generally yield by far the best compromise between data quality, acquisition time and radiation damage.

Bacterial Proteins↗
PubMed1987

Children in cars. Some aspects of the safety of children as car passengers in road traffic accidents.

The purpose of this study was to investigate child safety in cars from different aspects, such as the epidemiology of child injuries and injury assessment, restraint use effectiveness, restraint use limitations and drawbacks, data quality and improper use of child restraints. The materials used for the studies were of different types and sizes. Insurance materials were used for the epidemiological investigation and supplemented with questionnaires, for studies of restraint use effectiveness. Data on injuries reported by the police were used for studies of data quality and of the limitations and drawbacks of restraint use. Observational studies were conducted to detect improper use of child restraints and these were followed-up by dynamic barrier tests to assess possible consequences in frontal collisions. All injuries were classified according to the Abbreviated Injury Scale (AIS) and the risk of death and disability was predicted by RSC (Rating system for Serious Consequences) with modified figures for children. The main conclusions reached were that injury assessing methods derived for adults can be used also for children with some modifications concerning disability risks. Child restraint use was found to be effective in reducing injuries, especially the use of rearward-facing restraints. Injuries occurring in spite of restraint use were often minor in terms of fatality risks, but injuries to the neck and head may cause long-term consequences. The police was found to report only slightly more than half of the injured children reported to the insurance company. Misuse of child restraints was found to exist and may decrease restraint use effectiveness or induce injuries. On the basis of these studies it is recommended that child restraints be incorporated into cars as an in-built system with the same basic design as restraints that are available as extra equipment. Certain considerations should be paid, however, to those injuries occurring among restrained children that entail a risk of medical disability.

Accidents, Traffic↗
PubMed2003

Patient centered assessment of ankylosing spondylitis-specific health related quality of life: evaluation of the Patient Generated Index.

OBJECTIVE: To evaluate the Patient Generated Index (PGI) for the measurement of individualized health related quality of life in ankylosing spondylitis (AS). METHODS: The PGI asks patients to nominate areas of their lives affected by their disease that they consider the most important. Semistructured interviews with AS patients produced a trigger list of areas of life affected by AS. The PGI was self-completed by UK patients taking part in a multicenter postal survey. The instrument was assessed for data quality, reliability, validity, and responsiveness. RESULTS: The PGI had acceptable completion rates. Scores covered the available range and approximated normality. Test-retest reliability estimates support the use of the PGI in group evaluation (intraclass correlation coefficient > 0.80). Comparisons with scores for other health status instruments provided evidence for the validity of the PGI. The largest levels of correlation were found for the AS Quality of Life Questionnaire (ASQoL) and the EuroQol. The informed and open format of the PGI had the strongest linear relationship with responses to both specific and general health transition questions (p < 0.01), and was the most responsive format of the PGI. CONCLUSION: The PGI is the first AS-specific individualized measure of health related quality of life. There is good support for the content validity of the instrument and patient acceptability is high. Adequate levels of data quality and reliability support the use of the PGI in group evaluation. Moderate levels of responsiveness to changes in health were produced by the informed and open format of the PGI.

Adult↗
PubMed2007

Air quality assessment in Delhi: before and after CNG as fuel.

A number of policy measures have been activated in India in order to control the levels of air pollutants such as particulate matter, sulphur dioxide (SO(2)) and nitrogen dioxide (NO(2)). Delhi, which is one of the most polluted cities in the world, is also going through the implementation phase of the control policies. Ambient air quality data monitored during 2000 to 2003, at 10 sites in Delhi, were analyzed to assess the impact of implementation of these measures, specifically fuel change in vehicles. This paper presents the impact of policy measures on ambient air quality levels and also the source apportionment. CO and NO(2) concentration levels in ambient air are found to be associated with the mobile sources. The temporal variation of air quality data shows the significant effect of shift to CNG (Compressed Natural Gas) in vehicles.

Air Pollutants↗
PubMed1996

Using clinical and functional data for quality improvement in outcomes measurement consortia.

BACKGROUND: Using standardized measures, American Group Practice Association care providers compiled a national database from which patients could be tracked, allowing for epidemiologic comparisons among treatments, sources of care, and results. Within five years, the consortia expanded from 6 to 55 clinics and from a focus on total hip replacement surgery to eight different health conditions. DATA COLLECTION PROCESS: Reflecting areas of significant public concern, high prevalence, high cost, or research needs, both patient- and provider-source data are collected at group practices at standardized intervals: 6 months, 12 months, and annually thereafter. OUTCOMES DATA MANAGEMENT AND REPORTING: A readily adaptable database infrastructure allows data-collection tools to adapt individual questions to changing conditions in the health care environment while maintaining the integrity of the whole structure. Aggregate-level reports complement individual clinics' own internal analysis efforts by providing a context for the interpretation of results. CASE STUDIES: In a total hip replacement consortium (including more than 2,300 patients), early findings have shown that patients do not fully recover from surgery as quickly as they themselves anticipated. In the cataract consortium, data scores on near, distant, day, night, glare, and overall vision scales improve considerably after cataract surgery, giving clinics a new tool to monitor and improve performance. In the asthma consortium, one clinic reevaluated the distribution of peak flow meters and the reasons for their underuse after noting the low number of patients in the clinic that had peak flow meters. LESSONS LEARNED: Provider participation in study design, instrumentation, data analysis, and feedback is important, and physician buy-in and support are critical to the success of any outcomes initiative. Missing data are the greatest limitations of a longitudinal data set and are difficult to collect through follow-up. There is still much to be learned about what functional status and well being measures can show about the relationship between health care services and patient health.

Asthma↗
PubMedDate not supplied

Calibration of the DRASTIC ground water vulnerability mapping method.

Ground water vulnerability maps developed using the DRASTIC method have been produced in many parts of the world. Comparisons of those maps with actual ground water quality data have shown that the DRASTIC method is typically a poor predictor of ground water contamination. This study significantly improved the effectiveness of a modified DRASTIC ground water vulnerability map by calibrating the point rating schemes to actual ground water quality data by using nonparametric statistical techniques and a geographic information system. Calibration was performed by comparing data on nitrite plus nitrate as nitrogen (NO2 + NO3-N) concentrations in ground water to land-use, soils, and depth to first-encountered ground water data. These comparisons showed clear statistical differences between NO2 + NO3-N concentrations and the various categories. Ground water probability point ratings for NO2 + NO3-N contamination were developed from the results of these comparisons, and a probability map was produced. This ground water probability map was then correlated with an independent set of NO2 + NO3-N data to demonstrate its effectiveness in predicting elevated NO2 + NO3-N concentrations in ground water. This correlation demonstrated that the probability map was effective, but a vulnerability map produced with the uncalibrated DRASTIC method in the same area and using the same data layers was not effective. Considerable time and expense have been out-laid to develop ground water vulnerability maps with the DRASTIC method. This study demonstrates a cost-effective method to improve and verify the effectiveness of ground water vulnerability maps.

Calibration↗
PubMed1997

Interventions for improving information management in family practice.

Information management training has been neglected in family practice in the UK in the past. An adult learning model for such training is introduced. A pilot study using the adult learning approach showed improvements in information management processes over the six-month study period. The research project described in this paper compares the effectiveness of on-site training using adult learning methods, written information, and no intervention, in 33 family practices in the UK. Nine of the eleven practices in the on-site training group completed the training sessions and provided data, whereas only four of the eleven practices in the written information group provided data, and only three of the eleven practices in the control group did so. Preliminary analysis demonstrates that on-site training practices made considerable changes to the information systems in their practices, and appreciated the importance of high-quality data, both for patient care and reporting requirements. Full comparisons of data quality and information management methods are presented, and an assessment of priority training needs for maximum benefit is made.

Adult↗
PubMed2003

Interlaboratory variability in the quantification of new generation antiepileptic drugs based on external quality assessment data.

PURPOSE: To assess interlaboratory variability in the determination of serum levels of new antiepileptic drugs (AEDs). METHODS: Lyophilised serum samples containing clinically relevant concentrations of felbamate (FBM), gabapentin (GBP), lamotrigine (LTG), the monohydroxy derivative of oxcarbazepine (OCBZ; MHD), tiagabine (TGB), topiramate (TPM), and vigabatrin (VGB) were distributed monthly among 70 laboratories participating in the international Heathcontrol External Quality Assessment Scheme (EQAS). Assay results returned over a 15-month period were evaluated for precision and accuracy. RESULTS: The most frequently measured compound was LTG (65), followed by MHD (39), GBP (19), TPM (18), VGB (15), FBM (16), and TGB (8). High-performance liquid chromatography was the most commonly used assay technique for all drugs except for TPM, for which two thirds of laboratories used a commercial immunoassay. For all assay methods combined, precision was <11% for MHD, FBM, TPM, and LTG, close to 15% for GBP and VGB, and as high as 54% for TGB (p < 0.001). Mean accuracy values were <10% for all drugs other than TGB, for which measured values were on average 13.9% higher than spiked values, with a high variability around the mean (45%). No differences in precision and accuracy were found between methods, except for TPM, for which gas chromatography showed poorer accuracy compared with immunoassay and gas chromatography-mass spectrometry. CONCLUSIONS: With the notable exception of TGB, interlaboratory variability in the determination of new AEDs was comparable to that reported with older-generation agents. Poor assay performance is related more to individual operators than to the intrinsic characteristics of the method applied. Participation in an EQAS scheme is recommended to ensure adequate control of assay variability in therapeutic drug monitoring.

Anticonvulsants↗
PubMed1991

Interlaboratory variability in drug assay: a comparison of quality control data with reanalysis of routine patient samples. I: Anticonvulsant drugs and theophylline. Clinical Pharmacology and Toxicology Study Group, Italian Society for Clinical Biochemistry.

The interlaboratory variability in the assay of theophylline and various anticonvulsant drugs was evaluated in a 16-month prospective study by using two independent experimental approaches: (a) a conventional method based on the distribution of quality control (QC) lyophilized human sera spiked with the test drugs (phenytoin, phenobarbital, carbamazepine, valproic acid, primidone, theophylline); and (b) reanalysis by two to four reference laboratories of patients' samples randomly selected among those routinely assayed for phenytoin and theophylline by the 52 participating laboratories. For all tested drugs, precision as assessed by results on spiked QC samples was generally satisfactory, interlaboratory coefficients of variation (CV) being below 18.5% for all drugs tested except primidone (CV = 24.1%) at clinically relevant drug concentrations. For both phenytoin and theophylline, there was a good agreement between results obtained by individual reference laboratories (reference results) on routine samples. The correlation coefficients relating the original values to the means of the reference results were greater than 0.94. It is concluded that interlaboratory variability in the assay of the drugs included in this survey is relatively low not only when assessed by using conventional QC material, but also under strictly routine conditions.

Anticonvulsants↗
PubMed1999

Reducing cesarean birth rates with data-driven quality improvement activities.

Reduction of cesarean section rates has been a difficult process that has not been easily accomplished by the institution of guidelines. It is more a process of changing physician behavior rather than of medical education. This article analyzed the role of intensive feedback of outcomes to bring about such changes. Two large private obstetric services in San Francisco, CA, were studied. Intensive outcomes feedback using a computerized information system, The Perinatal Data Center, regarding cesarean birth rates and a variety of obstetric outcomes was provided to the medical and nursing staff at one hospital. The other center served as a control. After the first observation period, the outcomes system was introduced to the second hospital. Finally, "open label" feedback, intradepartmental release of everyone's key statistics with names attached, was performed. Active management of labor was not practiced at either hospital. Results. Cesarean birth rates were stable in the baseline period from 1980 through 1988 at 24% to 25%. Introduction of the Perinatal Data Center outcomes system was associated with a reduction to 21% at the first hospital with no change in the control hospital. Subsequent introduction of the system 3 years later in the control hospital resulted in a decline from 25% to 20.5%. After merger of the two obstetric units and the institution of "open label" feedback, an additional decline to 18.5% was observed. Conclusion. Physician practice patterns and cesarean birth rates can be altered with the intensive use of comparative outcome data and strong physician leadership. Nonblinded, intradepartmental distribution of outcomes is an even more effective tool.

Algorithms↗
PubMed1998

Multimodal hemodynamic neuromonitoring--quality and consequences for therapy of severely head injured patients.

Fifty-five head injured patients (GCS < 8) were studied at an average of 7.5 +/- 3.4 days on the ICU to check quality of hemodynamic monitoring and the consequences for therapy. Multimodal neuromonitoring included intracranial pressure (ICP), mean arterial pressure (MAP), cerebral perfusion pressure (CPP), endtidal CO2 (EtCO2) as well as brain tissue--pO2 (p(ti)O2), regional oxygen (rSO2) and jugular venous oxygen saturation (SjO2). Regional p(ti)O2 as well as global SjO2 were sensitive technologies to detect hemodynamic changes. However analyzing reliability and good data quality regional p(ti)O2 (up to 95%) was superior to jugular bulb oximetry (up to 50%). Longterm-measurements of rSO2 using near infrared spectroscopy reached, if possible, a restricted reliability (good data quality up to 70%) and sensitivity in comparison to p(ti)O2. Especially p(ti)O2 enabled detection of critical p(ti)O2 (< 15 mm Hg) in up to 50% frequency during the first days after trauma and a second peak after day 6 to 8 according to evidence of CPP insults. Knowledge of baseline p(ti)O2 and CO2-reactivity allowed minimizing risk of ischemia by induced hyperventilation and improvement on cerebral microcirculation after mannitol administration could be individually recognized.

Blood Pressure↗
PubMed1998

Using reference data on quality of life--the importance of adjusting for age and gender, exemplified by the EORTC QLQ-C30 (+3).

Interpretation of health related quality of life (HRQOL) results in cancer patients is facilitated by knowledge of the levels of HRQOL in the general population. However, direct comparisons can be misleading unless age and gender are considered. We demonstrate the derivation of age- and gender-specific 'expected' values from population reference values by means of simple calculations. This survey included 3000 randomly selected Norwegians above 18 years of age who received the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire (EORTC QLQ-C30 (+3) by mail. 1965 responses from 2,892 eligible persons (68%) were received. The population was divided into six disease groups based on self-reported health problems. The observed mean scale scores of the different groups deviated greatly from those obtained in the general population. The score for physical function, for example, was 72 for cancer patients and ranged from 73.3 to 82.5 in other disease groups, as opposed to 89.9 in the general population and 98.9 in those with no health problems. The range for one of the quality of life (QOL) scales was 57.7 to 84.7 compared with 73.7 in the general population. Expected mean scores for the patient groups were computed from the reference values, based on the concept of equivalence of age and gender. The differences between the observed mean scores and the reference values were strongly mediated by this method. The expected scores for physical function then ranged from 83.3 to 93.1 and from 70.3 to 75 for the QOL scale. The impact of age and gender on the reference data from the EORTC QLQ-C30 (+3) obtained in a general population shows that these variables must be considered when interpreting data on HRQOL for cancer patients. The demonstration of how to generate mean values which are adjusted according to the age and gender distribution of a population should increase the usefulness of this questionnaire among clinicians.

Adult↗
PubMed1998

Is the SF-36 suitable for assessing health status of older stroke patients?

INTRODUCTION: The Medical Outcomes Study short form 36 health survey (SF-36) is being increasingly used and recommended as a suitable measure of subjective health status. However, it is unlikely that any measure will be appropriate for all groups. We wished to determine the suitability of the SF-36 for assessing quality of life in older stroke patients. METHODS: A screening questionnaire was used to identify prevalent cases of stroke from a random sample of 2000 subjects aged 45 years and over. The SF-36 was included as part of a self-completion questionnaire posted to each stroke patient. Data quality indicators were analysed. RESULTS: We identified 104 cases of stroke and the response rate for the SF-36 questionnaires sent was 83%. Completion rates for individual items ranged from 66 to 96%. All items in the role physical and role emotional scales had completion rates < 75%. The percentage of subjects for whom an individual scale score could be computed ranged from 67 to 96%, being lowest for the role physical and role emotional scales. Floor effects were high (> 15%) for these two scales and for the social functioning and physical functioning scales. Ceiling effects were substantial (> 15%) for the two role effect scales and for social functioning and bodily pain. CONCLUSIONS: This study has shown high response rates from older stroke patients to a postal questionnaire incorporating the SF-36. The poor completion rates and consequent inability to compute scores for a large proportion of responders in certain scales raises concerns about the perceived relevance of these sections. Results for the response effects suggest that, on its own, the instrument is not suitable for assessing outcome. When data quality indicators were examined, it appears that postal administration of the SF-36 is not appropriate for assessing quality of life of older stroke patients.

Activities of Daily Living↗