Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Correction factor”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMed2003

Electron-probe X-ray microanalysis of individual particles of solid snow sediment with size factor correction.

A technique is proposed for X-ray electron-probe microanalysis (EPMA) of individual particles of solid snow sediment. Two sample preparation procedures were used to analyze the sediments. The PAP-method and the original bi-exponential model were used for matrix correction and the calculation of elemental composition. A method of calculating composition has been developed for approximately spherical individual particles, comparable in size with an area of X-ray generation. An analytical expression is proposed for determining the composition of these particles, taking account of their size. Including the size factor reduces the error of composition determination from 0.5-45 to 0.2-22% relative percent, for particles in the size range 1-3 microm.

Journal Article↗
PubMed1977

Correctable factors contributing to the anemia of dialysis patients.

Twelve out of 60 patients undergoing regular dialysis treatment were found to have an inappropriate degree of anemia. This was not related to duration on dialysis, square meter hours of dialysis or underlying renal disease. Radioactive methods were used to determine blood losses in the dialyzer, lines, at cannulation and from the gastrointestinal tract in the "anemic" patients. Ten of these patients were found to have excessive blood losses and appropriate measures to correct this produced a significant rise in hematocrit in all cases.

Anemia↗
PubMed1979

Effect of carboxyhemoglobin on the single breath diffusing capacity: derivation of an empirical correction factor.

The effect on measured DLco of different blood concentrations of COHb produced by breathing CO was studied in 19 healthy nonsmoking subjects. The DLco calculated without adjustment for blood COHb was found to be spuriously reduced by approximately 1% of the observed baseline value for each percent increase in blood COHb saturation. When measuring DLco of subjects who are likely to have elevated COHb blood levels, it is recommended that either blood COHb concentration or equilibrated alveolar PCO be determined in order to correct the DLco for the effect of COHb.

Adult↗
PubMed2002

Beyond immunochemotherapy: combinations of rituximab with cytokines interferon-alpha2a and granulocyte colony stimulating factor [corrected].

Monotherapy with the human-mouse chimeric anti-CD20 monoclonal antibody rituximab is effective and well tolerated in the treatment of indolent non-Hodgkin's lymphoma, but the majority of patients relapse. The combination of chemotherapeutic agents with rituximab results in greater efficacy, but at the cost of the increased toxicity associated with chemotherapy. To increase the efficacy of rituximab without compromising tolerability, the cytokines interferon-alpha2a, which has multiple immunomodulatory effects and enhances antibody-dependent cell-mediated cytotoxicity, and the granulocyte-colony stimulating factor, which enhances antibody-dependent cell-mediated cytotoxicity by neutrophils, have been combined with rituximab. In a randomized comparative study in patients with relapsed or untreated indolent non-Hodgkin's lymphoma, the addition of interferon-alpha2a significantly increased responsiveness to a second course of rituximab in patients with a partial response or minor response to an initial course of rituximab monotherapy. In a single-arm study in 20 patients with relapsed disease, the combination of granulocyte-colony stimulating factor with rituximab resulted in a longer duration of response than normally seen with rituximab monotherapy. In both studies, no significant increase in adverse events compared with rituximab monotherapy was reported. Currently available data suggest that the combination of rituximab with immunomodulatory cytokines result in increased efficacy without compromising tolerability.

Antibodies, Monoclonal↗
PubMed1996

The tissue thromboplastin inhibition test in the detection of lupus anticoagulants: importance of a correction factor eliminating the influence of fibrinogen level.

Tissue thromboplastin inhibition test (TTI) is a highly sensitive but poorly specific test used in the diagnosis of lupus anticoagulant (LA) which is usually requested for patient with inflammatory status. Therefore, we investigated the influence of fibrinogen level on TTI using Recombiplastin (Ortho), Neoplastine (Diagnostica Stago) and Thromborel S (Behring), in a group of 84 patients with fibrinogen levels ranging from 1.6 to 11.8 g/l. The highly significant (p < 0.0001) positive correlation observed between fibrinogen level and TTI with the 3 thromboplastins allowed the calculation of a new TTI value corrected for fibrinogen level named TTIfg. TTIfg was defined as TTI - ("S" x fibrinogen level) where "S" was the slope of the regression line defining TTI as a function of fibrinogen values. In the group studied, the low TTI specificity, respectively 64%, 67% and 75% with Recombiplastin, Neoplastine and Thromborel S, was greatly improved to respectively 95%, 93% and 95% when results were expressed as TTIfg. TTIfg remained as sensitive as TTI when evaluated in a group of 38 patients with previously diagnosed LA.

Fibrinogen↗
PubMed1991

Nerve growth factor corrects developmental impairments of basal forebrain cholinergic neurons in the trisomy 16 mouse.

The trisomy 16 (Ts16) mouse, which shares genetic and phenotypic homologies with Down syndrome, exhibits impaired development of the basal forebrain cholinergic system. Basal forebrains obtained from Ts16 and euploid littermate fetuses at 15 days of gestation were dissociated and cultured in completely defined medium, with cholinergic neurons identified by choline acetyltransferase (ChAT) immunoreactivity. The Ts16 cultures exhibited fewer ChAT-immunoreactive neurons, which were smaller and emitted shorter, smoother, and more simplified neurites than those from euploid littermates. Whereas the addition of beta-nerve growth factor (100 ng/ml) augmented the specific activity of ChAT and neuritic extension for both Ts16 and euploid cholinergic neurons, only Ts16 cultures exhibited an increase in the number and size of ChAT-immunoreactive neurons. Furthermore, Ts16 ChAT-immunoreactive neurites formed varicosities only in the presence of beta-nerve growth factor.

Animals↗
PubMed1982

Total effective time of the forced expirogram in disease: sources of error and a correction factor.

Effective time of the forced expirogram is a sensitive index for the detection of mild airways obstruction. However, there is evidence that this measurement is not superior to maximum flow rates in the lower half of the forced vital capacity or even FEV1 and FEV1% in some patients suffering from obstructive lung disease. Furthermore we noticed that in some patients with a decrease of the forced vital capacity caused by exacerbation of airways obstruction, the effective time was not appreciably changed. We concluded that this apparent disadvantage of the effective time is the result of the different forced vital capacities. To eliminate this error we transformed the forced expirogram to the equivalent curve that the patient would produce, if his forced vital capacity was equal to the predicted mean value for his age, sex, and height. The derived corrected total effective time seems to have increased sensitivity for detection of small changes in expirograms obtained from the same subject or from different subjects.

Asthma↗
PubMed2003

A corrective factor for scoring small finger function using the Littler's line and area under a Gaussian curve method.

PURPOSE: The Littler's line and area under a Gaussian curve method for scoring digital range of motion is an extremely convenient method for evaluating functional return after injury. This method, although being sufficiently accurate for other fingers, leads to a faulty estimation of function in the small finger. METHOD: Twenty-six normal hands in 14 volunteers were scored by using the earlier-described method. The statistical significance of the resulting error in small finger function was determined by using the standard error of difference between means. Corrective methods were determined and their statistical validity was established by using the same test. RESULTS: There was a consistent error in scoring of small finger flexion by about 2.26% using the earlier-described method, which was statistically significant. The error was caused by a radial deviation of the small finger on full flexion. To eliminate the error the proximal reference point of the small finger needs to be shifted radially. The amount of this shift is determined either by using the opposite hand if normal, or by an amount equal to 0.16 times the length of the small finger. CONCLUSIONS: The use of the new reference point for calculating the functional score of the small finger has added to the accuracy of a simple and realistic scoring system for flexion injuries. This eliminates a potential source of error and makes our analysis that much more reliable.

Adult↗
PubMed1987

Volume/pressure curve of total respiratory system in paralysed patients: artefacts and correction factors.

The volume/pressure (V/P) curve of the total respiratory system in paralysed patients is drawn assuming that volume changes of the respiratory system (delta V resp) equals volume displacement of the measuring apparatus (delta V syr), usually a supersyringe. However, in 93 VP curves we found that O2 removed from the lung-syringe system during the procedure (proportional to the time) largely exceeds the CO2 added to the lung-syringe system (delta V gas). This results in a net loss of volume from the system (delta V resp less than delta V-syr). Deflation compliance, hysteresis area and ratio are significantly affected by this phenomenon. Inflation compliance is less influenced by delta V gas, partially compensated by the intrapulmonary gas expansion due to the temperature changes. We conclude that the parameters computed on the deflation limb of V/P curve are misleading if proper correction of the volume scale is not introduced.

Adolescent↗
PubMed1999

Hemoglobin correction factors for estimating the prevalence of iron deficiency anemia in pregnant women residing at high altitudes in Bolivia.

This study had two primary objectives: 1) to derive a method to determine hemoglobin cutoffs that could be used to better estimate the prevalence of iron deficiency anemia in pregnancy at high altitudes and 2) to estimate the prevalence of anemia in a sample of pregnant women residing in two cities in Bolivia, La Paz (3,600 meters) and El Alto (4,000 meters). We derived a hemoglobin-altitude curve from previously published data on the mean hemoglobin concentrations of nonanemic women of childbearing age at various altitudes. In addition, we abstracted data on hemoglobin concentration during pregnancy from medical records of women from La Paz and El Alto who had given birth at a maternity hospital in La Paz between January and June of 1996. Using our approach and two other previously published, currently used methods, we calculated and compared prevalences of iron deficiency anemia in this population using hemoglobin cutoffs determined from a hemoglobin-altitude curve corrected for pregnancy. The hemoglobin-altitude curve derived in this study provided a better fit to data for women of childbearing age than the two other models. Those models used cutoffs based on non-iron-replete populations of children or men, both of which were residing below 4,000 m, and then extrapolated to women and higher altitudes. The estimated prevalences of iron deficiency anemia in pregnancy using the hemoglobin cutoffs determined in this study were higher than those estimated by the two other approaches.

Adult↗
PubMed1999

Absorbed dose beam quality correction factors kappaQ for the NE2571 chamber in a 5 MV and a 10 MV photon beam.

Dose to water (Dw) determination in clinical high-energy photon beams with ionization chambers calibrated in terms of absorbed dose to water has been proposed as an alternative to ionization chamber dosimetry based on air kerma calibrations. Dw in the clinical beam is derived using a kappaQ factor that scales the absorbed dose calibration factor in the reference beam to the absorbed dose calibration factor in the user beam. In the present study kappaQ values were determined for the NE2571 chamber in a 5 MV and a 10 MV high-energy photon beam generated at the 15 MeV high-intensity electron linac of the University of Gent. A set of three NE2571 chambers was calibrated relative to the Gent sealed water calorimeter both in 60Co and in the linac beam at a depth of 5 cm and a source to detector distance of 100 cm. Two high-purity chemical water systems were used in the detection vessel of the calorimeter, H2-saturated and Ar-saturated pure water, which are both supposed to give a zero heat defect. TPR20(10) and %dd(10) have been evaluated as beam quality specifiers. Simulations using the BEAM/DOSXYZ Monte Carlo system were performed to evaluate potential corrections on the measured beam qualities. The average kappaQ values measured for the three NE2571 chambers in the 5 MV and 10 MV photon beams are 0.995 +/- 0.005 and 0.979 +/- 0.005 respectively. For the three chambers used, the maximum deviation of individual kappaQ values is 0.2%. The measured beam quality specifiers %dd(10) and TPR20(10) are 67.0 and 0.705 for the 5 MV beam and 75.0 and 0.759 for the 10 MV beam. Although our beam design is very different from those used by other investigators for the measurement of kappaQ values, the agreement with their results is satisfactory showing a slightly better agreement when %dd(10) is used as the beam quality specifier.

Belgium↗
PubMed2006

Assessment of residents' loss of interest in academic careers and identification of correctable factors.

OBJECTIVE: To quantify interest in an academic career at the dermatology resident and residency applicant level. DESIGN: Cross-sectional survey. PARTICIPANTS: Dermatology residents attending a basic science course and residency applicants applying to a single residency program. MAIN OUTCOME MEASURES: Self-reported level of interest in an academic dermatology career, reasons for losing interest in academics, and area of desired primary academic contribution. RESULTS: One hundred nine of 230 dermatology applicants and 130 of 190 dermatology residents completed the survey. Seventy-nine applicants (72.5%) and 48 residents (36.9%) were interested in an academic career. Thirty-three of 47 residents (70.2%) and 63 of 79 applicants (79.8%) interested in an academic career hoped to make their primary academic contribution as teacher-clinicians, while only 7 residents (14.9%) and 15 applicants (19.0%) planned to primarily contribute through basic or clinical research. Thirty-eight resident respondents (29.2%) reported losing interest in academics for the following primary reasons: bureaucracy, 24 (63.2%); salary differential/financial issues, 20 (52.6%); lack of effective mentorship, role model, or professional guidance, 19 (50.0%); and location or practice environment, 10 (26.3%). CONCLUSIONS: Many residents report losing interest in pursuing a career in academic dermatology. Many reasons for this are not easy to correct. However, half of those residents primarily lose interest because of a lack of mentors, role models, and career guidance. Methods to improve this perception and experience should be sought. Strategies should also be developed to cultivate future teacher-clinicians, where most of the interest lies.

Academic Medical Centers↗