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Biomedical subjects

G Cormier

Publications and source records attributed to G Cormier.

11 recordsLinked to original sources
PubMed2000

Genetic algorithm for ellipsometric data inversion of absorbing layers.

A new data reduction method is presented for single-wavelength ellipsometry. A genetic algorithm is applied to ellipsometric data to find the best fit. The sample consists of a single absorbing layer on a semi-infinite substrate. The genetic algorithm has good convergence and is applicable to many different problems, including those with different independent measurements and situations with more than two angles of incidence. Results are similar to those obtained by other inversion techniques.

Algorithms↗
PubMed1996

Anterior stromal punctures for bullous keratopathy.

OBJECTIVE: To evaluate the therapeutic effects of anterior stromal punctures (ASP) in patients with bullous keratopathy (BK). PATIENTS AND METHODS: Twenty-seven patients awaiting penetrating keratoplasty with a diagnosis of BK were examined. They were seen before treatment with ASP and 1, 4, and 12 weeks after treatment. The examination included slit-lamp examination, photography of the cornea, ultrasonic pachymetry, central esthesiometry, and pneumotonometry. Subjective evaluations of pain, discomfort, and photophobia were also done using a visual scale model. Photographs were analyzed by computer-assisted planimetry and used to measure the corneal surface covered by bullae and microcysts. Pretreatment and posttreatment values (mean +/- SEM) were compared using the Student paired t test. RESULTS: At 3 months, a significant reduction in pain was noted. A decrease in the mean corneal surface covered by bullae (BKPreASP = 2733 +/- 553 microns2; BK3mo = 1006 +/- 356 microns2, P = .004) was observed. A decrease in the esthesiometry (E) measurement (EPreASP = 3.5 +/- 0.4 cm; E3mo = 1.3 +/- 0.3 cm, P < .001), an increase in corneal thickness ([CT] CTPreASP = 869 +/- 24 microns; CT3mo = 902 +/- 21 microns, P < .001), and a decrease in the number of quadrants through which iris (I) details could be seen (IPreASP = 1.7 +/- 0.3; I3mo = 1.2 +/- 0.3, P = .015) were also noted. These findings corroborate the clinical observation of increased subepithelial fibrosis following ASP. CONCLUSIONS: Anterior stromal punctures reduce bullae formation and alleviate pain in patients with BK, and they constitute a valuable alternative to penetrating keratoplasty should surgery be delayed or contraindicated.

Adult↗
PubMed1996

Apolipoprotein E polymorphism in a French Canadian population of northeastern Quebec: allele frequencies and effects on blood lipid and lipoprotein levels.

Apolipoprotein E phenotypes and plasma lipid and lipoprotein levels were determined in 435 individuals (233 men, 202 women) of French Canadian descent living in northeastern Quebec. This region is known for its high frequency of mutant genes responsible for rare genetic disorders. Total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglyceride levels were adjusted for age, height, weight, body mass index (BMI), and waist circumference using regressions performed separately in men and in premenopausal and postmenopausal women. The APOE allele frequencies in this population-based sample were 0.137, 0.749, and 0.114 for the *2, *3, and *4 alleles, respectively. APOE2 (APOE 2,2 and APOE 3,2) subjects had lower total and LDL cholesterol levels than APOE3 (APOE 3,3) subjects. In APOE4 (APOE 4,3 and APOE 4,4) men and postmenopausal women levels of total and LDL cholesterol and triglycerides were significantly higher than in the corresponding APOE3 subjects. The *2 allele was also found to be associated with higher triglyceride levels in men and postmenopausal women. Men of the APOE4 group also presented lower HDL cholesterol levels. Although the impact of APOE polymorphism on blood lipid and lipoprotein levels in this French Canadian population is similar to what has been reported in other white populations, the frequency of the *2 allele is among the highest ever reported. This finding is discussed in terms of the founder effect characterizing the Quebec population.

Abnormalities, Multiple↗
PubMed1977

A study of the applicability of a truly objective measurement model in medical education.

The main purpose of this study is to examine a new measurement model, to explore the range of situations to which it can be applied, and to establish its value in the improvement of the decision-making process in medical education. The objective of this set of investigations is thus to help fill the gap between theory and practice, particularly in the light of a strong movement toward criterion-referenced testing.

College Admission Test↗