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Results for “sensitivity analysis”

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At least 433 records · Page 24Linked to original sources
PubMed1988

Rapid and sensitive analysis of 8-methoxypsoralen in plasma.

A new method has been developed to extract 8-methoxypsoralen (8-MOP) from human plasma and to prepare samples for high performance liquid chromatography (HPLC) analysis. Plasma samples are passed through solid phase extraction cartridges that are essentially HPLC "microcolumns" consisting of a bonded silica sorbent that, after activation, selectively retain 8-MOP and then release it when exposed to an eluting solvent. The 8-MOP collected from the cartridge is analyzed by reversed phase HPLC. With this new technique, the 8-MOP is completely recovered and as little as 10 ng/ml can be detected in a 1-ml plasma sample. The average plasma level in a series of 17 patients who had ingested Oxsoralen (approximately 0.6 mg/kg) was 117 ng/ml (+/- 79).

Humans↗
PubMed1980

Errors in oxygen concentration analysis: sensitivity of the IMI analyser to nitrous oxide.

The sensitivity to nitrous oxide of the IMI oxygen analyser (Model 3300) has been tested. Even if the manufacturer's checks are performed and the analyser appears to be functioning correctly, the reading given by the IMI oxygen analyser may be seriously affected by the presence of nitrous oxide. There is a wide variation in the sensitivity to N2O between different instruments, and this variation is partly a function of the electrode. The influence of nitrous oxide on a particular meter may be assessed by placing the probe in 100% nitrous oxide and noting the shift of the meter from zero.

Electrodes↗
PubMed1990

Metabolic control analysis. Sensitivity of control coefficients to elasticities.

This paper illustrates a method to calculate the sensitivities of control coefficients to the elasticities which determine their values and it is shown that these sensitivities are systemic properties. We show, both theoretically and with a practical example, how they can be used to investigate: (a) the relative importance of a particular elasticity in the determination of the value of a control coefficient; (b) the effect of experimental error on the values of the control coefficients and (c) the construction of confidence limits around the values of the control coefficients.

Animals↗
PubMed1991

Sensitive analysis of genetic heterogeneity of adenovirus types 3 and 7 in the Soviet Union.

An analysis of adenovirus strains isolated in the Soviet Union from 1976 to 1988 revealed four genome types of adenovirus type 3 (Ad3), i.e., Ad3a4, Ad3a9, Ad3a10, and Ad3a11, and four genome types of adenovirus type 7 (Ad7), i.e., Ad7p, Ad7a, Ad7a(1-5), and Ad7f1, identified with the DNA restriction enzymes BamHI, BglII, and HindIII. Three of them, Ad3a10, Ad3a11, and Ad7f1, are newly discovered. The genetic heterogeneity of adenoviruses was examined with restriction endonuclease Cfr13I with a 4-base recognition cleavage site. Eighteen different restriction patterns were identified among 21 selected Ad3 strains after cleavage of DNA with Cfr13I. Eight different subtypes were identified among 20 Ad7 strains by the same technique. For estimation of the relationships among these genome subtypes, pairwise analyses of comigrating DNA restriction fragments from isolates of Ad3 and Ad7 were done after digestion with Cfr13I or with restriction endonucleases recognizing DNA sequences of 6 bp. Surprisingly, the results were very discrepant.

Adenovirus Infections, Human↗
PubMed1979

Regulation of simian virus 40 transcription: sensitive analysis of the RNA species present early in infections by virus or viral DNA.

We have examined the discrete species of simian virus 40 (SV40) RNA present very early in infection of monkey cells with wild-type virus, with mutant tsA58 virus, and with the corresponding DNAs to distinguish between two classes of models for control of late transcription: (i) positive control mediated by large-T antigen and (ii) negative control mediated by a repressor protein associated with viral DNA in the virion. Total cytoplasmic or nuclear polyadenylated RNAs from infected cells were denatured with glyoxal, separated by electrophoresis on agarose gels, and transferred to diazobenzyloxymethyl paper. The positions of specific early and late RNA species were determined with region-specific SV40 DNA probes. The technique can detect individual RNAs present at the level of less than one copy per cell. After 9.5 h at 37 degrees C, appreciable amounts of two early RNAs (2.6 kilobases [kb] and 2.9 kb) were present in the cytoplasm of cells infected with wild-type virus or DNA, along with much smaller amounts of two late RNAs, 1.6 kb (16S) and 2.5 kb (19S). The amounts of the late RNAs were reduced, but they were still synthesized in the presence of cytosine arabinoside, an inhibitor of DNA synthesis. In comparable infections with tsA58 virus or DNA at nonpermissive temperature (41 degrees C), substantial amounts of the two early RNAs were again present, but the two late RNAs could not be detected. However, small amounts of the late RNAs were found when infections with tsA58 virus or DNA were prolonged to 30 h at 41 degrees C. These results are not consistent with negative control of late transcription through the action of a repressor and, taken together with other data, suggest that T antigen has an active role in late RNA synthesis. Specific early and late viral RNAs were also detected in the nuclear poly(A)(+) fractions and were similar in size to the RNA species found in the cytoplasmic polyadenylated fractions. The late nuclear RNAs (1.8 and 2.9 kb) were significantly larger than the late cytoplasmic species, possibly because they are precursors. The 2.6- and 2.9-kb early RNAs found in the cytoplasm are probably the messengers for large-T and small-t antigens, respectively.

Animals↗
PubMedDate not supplied

Sensitive analysis of apoptosis using confocal laser scan microscopy.

Application of the TUNEL method and immunostaining cell-specific markers to a whole isolated glomerulus in combination with confocal laser scan microscopy can be used to analyze cell turnover including apoptosis within glomeruli. Furthermore, the technologies can be used to deepen our understanding of glomerular cell biology and pathophysiology at the cellular and molecular levels.

Animals↗
PubMed2004

A note on the use of sensitivity analysis to explore the potential impact of declining institutional care utilisation on disability prevalence.

Many health and disability surveys are conducted using the non-institutionalised population as a sampling frame. Consequently, it is possible that changes in the utilisation of institutional care could account for all or part of any change in the observed prevalence of functional limitation, disability or other health state, based on samples from the non-institutionalised population. Using conditional probability arguments, I present an adjustment formula for computing health state prevalences for the non-institutionalised population under a scenario in which health state prevalences are held constant except for movement into the non-institutionalised population of individuals who would formerly have been in institutional care. By comparing the adjusted prevalence with observed non-institutionalised health state prevalences the contribution of changes in institutionalisation to observed changes in the non-institutionalised health state prevalence can be assessed.

Journal Article↗
PubMed1998

Soft-copy sonography: cost reduction sensitivity analysis in a pediatric hospital.

OBJECTIVE: Our objective was to determine whether interpreting sonograms of pediatric patients using soft-copy (computer workstation) instead of laser-printed film could reduce costs for a pediatric radiology department. We used theoretic models of growth to analyze costs. MATERIALS AND METHODS: The costs of a sonographic picture archiving and communication system (three interface devices, two workstations, a network server, maintenance expenses, and storage media costs) were compared with the potential savings of eliminating film and increasing technologist efficiency or reducing the number of technologists. The model was based on historic trends and future capitation estimates that will reduce fee-for-service reimbursement. The effects of varying the study volume and reducing technologists' work hours were analyzed. RESULTS: By converting to soft-copy interpretation, we saved 6 min 32 sec per examination by eliminating film processing waiting time, thus reducing examination time from 30 min to 24 min. During an average day of 27 examinations, 176 min were saved. However, 33 min a day were spent retrieving prior studies from long-term storage; thus, 143 extra minutes a day were available for scanning. This improved efficiency could result in five more sonograms a day obtained by converting to soft-copy interpretation, using existing staff and equipment. Alternatively, five examinations a day would equate to one half of a full-time equivalent technologists position. Our analysis of costs considered that the hospital's anticipated growth of sonography and the depreciation of equipment during 5 years resulted in a savings of more than $606,000. Increasing the examinations by just 200 sonograms in the first year and no further growth resulted in a savings of more than $96,000. If the number of sonograms stayed constant, elimination of film printing alone resulted in a loss of approximately $157,000; reduction of one half of a full-time equivalent technologist's position would recuperate approximately $134,000 of that loss. CONCLUSION: Soft-copy sonography can save money through improved technologist efficiency, thereby increasing the number of sonograms obtained and revenue generated. If the number of sonograms does not increase, elimination of printing costs and reduction of staff technologists will not result in a savings.

Cost Savings↗
PubMed2000

Sensitivity analysis of risk assessment programs to various input parameters.

HESP 2.b risk assessment program was studied in detail concerning the effect of changing different input parameters for the output ADI values calculated by the program. We used the standard Netherlands 1.0 scenario offered by the program. With this we fixed a lot of input parameters which define the area, human and animal recipient parameters etc. The remaining 31 unfixed parameters were fixed at first to "BASE" input values and the BASE output values were calculated by HESP. Later we chose only one parameter at a time and changed it to an another value. The calculated ADI values were then compared to BASE output values. Seven parameters (soil type, soil usage, site length, soil pH, groundwater fraction in drinking water, basement floor type and Qev) were studied. We found, that changing soil pH or Qev have not any influence on the output ADI values in case of any contaminant. Soil type change has not any effect on the output ADI value in case of Pb or Cd but it seems to play important role in all cases of the four organic material we investigated. Changing soil usage have influence on the output ADI value almost in every case. It seems to be linear relation between the maximal concentration of contaminant and calculated ADI. Changing the site length and basement floor type gave in some cases different ADI values compared to BASE values. If we alter the groundwater fraction in drinking water we got usually different ADI values. With Risc Human risk assessment program we got similar results: nor the changes in soil type, site diameter or soil pH gave any changes in output ADI values. Our results hint that using HESP and Risc Human requires enhanced caution.

Adult↗