Note on B-splines, wavelet scaling functions, and Gabor frames

Let g be a continuous, compactly supported function on such that the integer translates of g constitute a partition of unity. We show that the Gabor system (g,a,b), with window g and time-shift and frequency-shift parameters a,b>0 has no lower frame bound larger than 0 if b=2,3,... and a>0. In particular, (g,a,b) is not a Gabor frame if g is a continuous, compactly supported wavelet scaling function and if b=2,3,... and a>0. We give an example for our result for the case that g=B/sub 1/, the triangle function supported by [-1,1], by showing pictures of the canonical dual corresponding to (g,a,b) where ab=1/4 and b crosses the lines N=2,3,.     

The liberal ophthalmologists of the northern France and management of children with vision deficiencies

PURPOSE: The purpose of this analysis was to appreciate the management of visually handicaped children outside specialized structures. We also assessed relays between primary physicians, hospitals and specialized structures. METHOD: A 12-question survey was sent to 144 liberal ophthalmologists of the North of France. The questionnary included 12 questions. We compared the results to litterature. RESULTS: The response-rate was 59.6%. This study indicated that the observed children by the liberal ophtalmologists had more simple diseases than in specialized structures. In hospitals, it seemed that the ophtalmologists diagnosed more severe diseases. These practitioners diagnosed some of these diseases. However some of diagnosis were to late. This study showed that specialized structures were not enough known by the practitioners who detected this handicap and that the families prefered the taking in charge near their home. CONCLUSION: We demonstrated the necessary organisation of precocious and systematic detection, and the necessary information to all practitioners on specialized structures.     

Health trajectories: long-term dynamics among black and white adults

Flow cytometry is a unique technology useful in the examination of effects of immunotoxic agents on target cells of the immune system. The purpose of this workshop was to provide an overview of the use of flow cytometry in new and established models of immunotoxicity, with emphasis on the potential applications, assay validation, and potential pitfalls. This overview begins with a discussion of methods useful in the assessment of Ca2+-dependent mechanisms of lymphoid cell activation in surface marker-defined human B cells, T cells, and monocytes. A discussion of the use of flow cytometry in analysis of apoptosis is also presented in this paper. The second paper presents data on the development and use of flow cytometry as an alternative to a Cr51 release assay for an assessment of cytotoxic T cell activation. The use of surface markers for characterizing and distinguishing the effects of chemical irritants from sensitizers is next presented, followed by an overview of the use of fluorescent probes to assess cell thiol status and overall oxidant-induced injury to lymphoid cells. Finally, an interlaboratory study designed to compare and evaluate the use of flow cytometry procedures in rat splenic cell subtyping is presented. Overall, these studies demonstrate the utility of flow cytometry assays in immunotoxicologic research, but further efforts are needed in the validation of many of these assays for routine use in immunotoxicologic testing.     

Experimental peri-implant tissue breakdown around hydroxyapatite-coated implants

Factor V Leiden mutation was initially detected in thrombophilic patients and relatives by PCR RFLP (Restriction Fragment Length Polymorphism) according to Bertina (1). This technique presents some drawbacks and the current trend is to simplify the diagnosis. We describe a technique of Allele Specific Amplification (ASA) which is optimized in terms of reliability: an additional mismatch in antepenultimate position enables to obtain the same specificity as PCR RFLP. Furthermore, coamplification of internal control warrants an optimal sensitivity. All the PCR have been simplified: the DNA extraction improvement allows to analyse the genotype with only a few microliters of whole blood whatever the anticoagulant and the procedure of preservation (freezing, dried blood spots, storage at +4 degrees C for several days). This technique saves time. Moreover, full automation of the ASA technique may be shortened thanks to the lack of extraction and the positive/negative reading of the PCR signal.     

Linkage analysis under locus heterogeneity: behaviour of the A-test in complex analyses

The admixture test (A-test) is a popular method for the analysis of linkage data when locus heterogeneity is suspected. It can be applied on pairwise linkage data, multipoint data and even for the simultaneous analysis of data from multiple dispersed candidate regions. However, very little is known about the conditions for the use of the method under these divergent circumstances. By performing analytical evaluations, we demonstrate that the A-test is inconsistent if there is a relationship between the phenotype and the probability of being linked. Biased estimates of the recombination fraction (theta) and the proportion of linked families (alpha) may occur if the actual frequency of linked families is not identical among small and large families. We conclude that the A-test should be used with caution if the phenotype and the probability of developing the phenotype at a certain age cannot be shown to be equal for family members of linked and unlinked families. If dissimilarities in family size cannot be ruled out, the extent of bias should be considered and size specific alpha-values should be used in risk calculations.     

Postoperative radiotherapy with concurrent cisplatin appears to improve locoregional control of advanced, resectable head and neck cancers: RTOG 88-24

PURPOSE: Despite aggressive surgery and postoperative radiation therapy, only 30% of patients who have advanced, potentially resectable carcinomas of the head and neck survive for 5 years. In the hope of improving this situation we studied the effect of postoperative radiotherapy delivered concurrently with cisplatin. METHODS AND MATERIALS: Patients who had Stage IV tumors and/or involved surgical margins received 60 Gy in 30 fractions over 6 weeks plus 100 mg/m2 of cisplatin on radiotherapy days 1, 23 and 43. Fifty-two patients participated in this trial and 51 were evaluated. Forty-three (84%) patients had pathologic T3 or T4 disease, 43 (84%) had Stage IV disease, and 27 (53%) had histologically involved surgical margins. RESULTS: Severe and life-threatening toxicities occurred in 20% and 12% of patients, respectively; the most common drug-related toxicities were leukopenia, anemia, nausea, and vomiting. Seventeen patients (43%) remain alive with no evidence of disease. Four patients (8%) died with no evidence of neoplastic disease, and one patient has died of a second independent malignancy. By actuarial analysis at 3 years, 48% of patients are alive, 81% have locoregional control of disease, and 57% are free of distant metastases. CONCLUSIONS: Based on comparison with similar patients treated in a prior Radiation Therapy Oncology Group/Intergroup trial (RTOG), we conclude that postoperative radiotherapy with concurrent cisplatin may improve locoregional control rates and should be prospectively tested.