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The digitization of aircraft cockpits places high demands on the colour vision of pilots. The present study investigates colour vision changes upon acute exposure to hypobaric hypoxia. The digital Waggoner Computerized Color Vision Test and the Waggoner D-15 were performed by 54 healthy volunteers in a decompression chamber. Respective altitude levels were sea level, 10,000 or 15,000 ft for exposure periods of 15 and 60 min, respectively. As for 60 min of exposure a significant decrease in colour perception was found between subjects at 15,000 ft as compared to the control group as well as between subjects at 15,000 ft as compared to subjects at 10,000 ft. No significant difference was found in the comparison within the 15,000 ft groups across time points pre-, peri-, and post-exposure. Thus, pilots appear to experience only minor colour vision impairment up to an exposure altitude of 15,000 ft over 60 min of exposure. Keywords: Colour vision, Pilot assessment, Hypobaric hypoxia, Aircraft, Eye, Author(s): F. Liebold[sup.1,8], W. Adler[sup.5], S. Jansen[sup.3], J. P. Klussmann[sup.3], M. Meyer[sup.4], L. Nehrlich[sup.1], J. Schmitz[sup.1,7], A. Vingerhoets[sup.6], L. M. Heindl[sup.2] and J. Hinkelbein[sup.9] Introduction Prompt and accurate colour recognition [...]

OBJECTIVE: Increasing effort has been put in the implementation and certification of head and neck tumor centers in order to establish standardized, quality assured health care for head and neck tumor patients. This study evaluated survival rates after treatment in a certified head and neck tumor center (CHNTC) vs. a non-certified head and neck tumor center (non- CHNTC) in Middle Franconia, Germany. PATIENTS AND METHODS: Age, sex, possible obituary, and typical relevant prognostic variables were analyzed. Diagnosis was recorded according to ICD10. Clinical and pathological TNM staging, tumor grading, localization, R-stage, and morphology were assessed (ICD- 0). Patients diagnosed with oral cancer (N=1047) were divided into groups based on where they received their primary treatment; CHNTCs or non-CHNTCs. RESULTS: Patients treated at CHNTCs had significantly higher survival rates vs. those treated at non-CHNTC (p=0.023) in univariate analysis. In a Cox regression model, survival rates for patients with pN0 and pN+ stage were similar at both types of centers. Men with pN0 had significantly lower survival rates (HR=0.497, p<0.001). Age had a statistically significant influence on survival rates independently from pN stage (HR=1.031 per year, p<0.001 in both groups). CONCLUSIONS: Patients treated at CHNTC had better survival rates than those treated at non-CHNTC. [ABSTRACT FROM AUTHOR]

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Objectives: Comparison of classification methods using data of one clinical study. The tuning of hyperparameters is assessed as part of the methods by nested-loop cross-validation.Methods: We assess the ability of 18 statistical and machine learning classifiers to detect glaucoma. The training data set is one case-control study consisting of confocal scanning laser ophthalmoscopy measurement values from 98 glaucoma patients and 98 healthy controls. We compare bootstrap estimates of the classification error by the Wilcoxon signed rank test and box-plots of a bootstrap distribution of the estimate.Results: The comparison of out-of-bag bootstrap estimators of classification errors is assessed by Spearman's rank correlation, Wilcoxon signed rank tests and box-plots of a bootstrap distribution of the estimate. The classification methods random forests 15.4%, support vector machines 15.9%, bundling 16.3% to 17.8%, and penalized discriminant analysis 16.8% show the best results.Conclusions: Using nested-loop cross-validation we account for the tuning of hyperparameters and demonstrate the assessment of different classifiers. We recommend a block design of the bootstrap simulation to allow a statistical assessment of the bootstrap estimates of the misclassification error. The results depend on the data of the clinical study and the given size of the bootstrap sample. [ABSTRACT FROM AUTHOR]

PurposeTo assess the combined diagnostic power of frequency-doubling technique (FDT)-perimetry and retinal nerve fibre layer (RNFL) thickness measurements with spectral domain optical coherence tomography (SDOCT).MethodsThe study included 330 experienced participants in five age-related groups: 77 'preperimetric' open-angle glaucoma (OAG) patients, 52 'early' OAG, 50 'moderate' OAG, 54 ocular hypertensivepatients, and 97 healthy subjects. For glaucoma assessment in all subjects conventional perimetry, evaluation of fundus photographs, FDT-perimetry and RNFL thickness measurement with SDOCT was done. Glaucomatous visual field defects were classified using the Glaucoma Staging System. FDT evaluation used a published method with casewise calculation of an 'FDT-score', including all missed localized probability levels. SDOCT evaluation used mean RNFL thickness and a new individual SDOCT-score considering normal confidence limits in 32 sectors of a peripapillary circular scan. To examine the joined value of both methods a combined score was introduced. Significance of the difference between Receiver-operating-characteristic (ROC) curves was calculated for a specificity of 96%.ResultsSensitivity in the preperimetric glaucoma group was 44% for SDOCT-score, 25% for FDT-score, and 44% for combined score, in the early glaucoma group 83, 81, and 89%, respectively, and in the moderate glaucoma group 94, 94, and 98%, respectively, all at a specificity of 96%. ROC performance of the newly developed combined score is significantly above single ROC curves of FDT-score in preperimetric and early OAG and above RNFL thickness in moderate OAG.ConclusionCombination of function and morphology by using the FDT-score and the SDOCT-score performs equal or even better than each single method alone. [ABSTRACT FROM AUTHOR]

A row of jets discharging normally into a confined cylindrical crossflow is numerically investigated using the control-volume-based finite difference method. Interest is focused on determining the relationship between the temperature trajectory and the upstream flow and geometric variables. Parameter variations studied include nozzle diameter, number of nozzles, duct radius, jet and mainstream volume-flow, temperature ratio, and dynamic pressure ratio. The dynamic pressure ratio, the number of nozzles, and nozzle spacing are found to be significant variables. A logarithmic function describing the relationship between penetration depth and dynamic pressure divided by the square of the number of nozzles is derived by fitting the data of the computation results. The values for penetration depth and nozzle spacing are described for optimum mixing. A suggested design procedure is presented, which can be used as a first approach in configuration design. [ABSTRACT FROM AUTHOR]

Four specific interleukin-2 (IL-2) surface binding proteins can be detected by covalent cross-linking of [125I]IL-2 to rat spleen cells that have been activated with various stimuli including concanavalin A (Con A), phytohaemagglutinin (PHA), calcium ionophore, and phorbol dibutyrate (PDB) with or without calcium ionophore. These four cross-linked proteins could not be demonstrated in either unstimulated T cells or in activated T cells when binding was performed in the presence of a 20-100- fold excess of unlabelled IL-2. The molecular weights of the four cross-linked proteins, after subtraction of the molecular weight contribution of IL-2 are: 53,000,70,000,90,000 and 118,000. The 53,000 MW protein was identified as the rat 11-2 receptor (IL-2R) 2-chain by immune precipitation. Additionally, results suggest that the rat LL-2R α-chain is tightly complexed to both the 118,000 and 90,000 MW IL-2 binding proteins. Purification of surface labelled proteins from activated cells using IL-2 affinity chromatography yields four proteins with similar molecular weight to those identified by cross-linking plus an additional non-ligand cross-linked protein of 46,000 MW. The 46,000 MW band may be a non-binding associated protein since it was not seen following [125I]IL-2 binding cross- linking. Tryptic digests and two-dimensional separation of the affinity-isolated proteins indicate that unique peptide maps are generated for the 46,000. 53,000 and 70,000 MW proteins and excludes the possibility that the bands identified by cross-linking represents cross-linking of multiple ligands to the 53,000 MW subunit. However, the 90,000 and 118,000 MW bands yield peptide maps that closely resemble each other suggesting that these binding proteins may be related. These results suggest that at least four IL-2 surface binding proteins may constitute the rat IL-2R system. [ABSTRACT FROM AUTHOR]

Although, major histocompatibility complex (MHC) class H antigen expression in allografts is thoroughly studied, regulation of the genes for these antigens is not fully understood. The graft-specific MHC class II genes are potentially important in determining the immunogenicity of graft but their detection in a mixed-cell `population such as in the allograft would require unambiguous differentiation of graft-specific class II expression from those in host lymphoid cells. With an oligonucleotide probe that specifically hybridizes to I-Ab mRNA from He2k haplotype mice, we have studied I-A gene expression in cardiac allografts heterotopically transplanted from B10.Br (H2k) to B10.D2 (H-22) mice. Normal B10.Br hearts do not have appreciable I-Ab transcripts as determined with this probe, but 4 days after allografting, a substantial increase in I-Abk messenger RNA (mRNA) content was noted in the allografted hearts which persisted for the next 2 days and then decreased concomitant with destruction of the heart. The increase in I-Abk mRNA preceded the expression of surface lak antigens on dendritic and endothelial cells in the allograft. These data indicate increased transcription of the 1-Ab gene in cells of graft origin suggesting that transcriptional regulation is the initial mechanism for expression of class II genes in allografts. The sustained rise in grail-specific class 11 mRNA also seen in these allografts suggests that increased mRNA stability may be another mechanism for the increased density of class II antigens in allografts undergoing rejection. [ABSTRACT FROM AUTHOR]

Concanavalin A (Con A)-induced cytotoxic activity, interferon (IFN) and interleukin-2 (IL-2) levels in cultures of spleen cells from young (2-3 months) and old (22-24 months) C578L/6 female mice were studied. Con A-activated spleen cells from old mice attained significantly higher cytotoxic activity compared with activated spleen cells from young mice. Activated spleen cells from old and young mice showed differences in their ability to lyse different types of target cells. Both could lyse P 815 cells, neither could lyse K562 cells, and only activated cells from old mice could lyse EL-4 cells. Cytotoxic spleen cells from the old mice were more sensitive to anti-asialo-GM-l and anti-Lyt-2.2 plus complement (C) treatment. While levels of IL-2 produced by spleen cells from young mice were higher, the addition of exogenous IL-2 had no effect on cytotoxic activity of the spleen cells from old mice. Exogenous IL-2, however, could lower cytotoxic activity of Con A-activated spleen cells from young mice. Activated spleen cells from old mice generated higher levels of IFN-γ while the addition of an anti-IFN-γ antibody boosted the level of cytotoxicity by Con A-activated spleen cells from young mice. These results suggest that IFN-γ may act as a feedback inhibitory signal regulating the levels of cytotoxicity induced in spleen cells from young mice in response to Con A. The cytotoxic activity generated in Con A-activated spleen cells from old mice reflects a defect in this feed-back regulation. [ABSTRACT FROM AUTHOR]

Groups of 6-week-old female C57B1/6 mice were fed a normal diet with recommended levels of all vitamins Dr a vitamin-deficient (VD) diet containing half of the recommended level of each vitamin. At different time periods (1-11 weeks) after the initiation of diets, basal natural killer (NK) activity, interleukin-2 (IL-2) and concanavalin A (Con A)-induced cytotoxic activity, Con A-induced IL-2 production and levels of allospecific cytotoxic T cell activity generated in a mixed lymphocyte culture (MLC), were studied in spleen cells derived from control and VD mice. Results indicated that: (i) spleen NK activity remained normal until 2 weeks after the initiation of VD diet, fell steeply to tow levels at the 4 and 5 week time points and remained depressed thereafter; (ii) IL-2- and Con A-induced levels of cytotoxic activity in spleen cells derived from VD mice declined at 4 weeks alter the institution of VD diet, and then remained low throughout the study; (iii) the capacity of spleen cells from VD mice to generate IL-2 in response to Con A and cytotoxic T cells in response to allogeneic spleen cells, was normal at 1 and 4 weeks alter initiation of the VD diet and was markedly depressed at the 6 and 9 week time points. These results suggest that partial combined deficiencies of dietary vitamins strongly influence assays of immune function. [ABSTRACT FROM AUTHOR]