The characteristics and measuring technique of refractory dissolved organic substances in urban runoff.

It is considered that refractory dissolved organic substances have caused an increase in the COD concentration in Lake Biwa in recent years. We investigated the organic matter in the first flush of stormwater runoff from a road in the watershed area of the lake, and studied the possibility of improvement in the water environment from that aspect. After percolating the stormwater through soil, we analyzed organic substances fractionated by using GPC-TC. And we examined the effect of removal of organic substances by comparing the peak height before and after percolation. In the result of the experiments, we found that soil infiltration reduced the refractory dissolved organic substance and we successfully designed a system for a simple and easy experimental facility to treat urban runoff.     

A general discrete contour model in two, three, and four dimensions for topology-adaptive multichannel segmentation

We present a discrete contour model for the segmentation of image data with any dimension of image domain and value range. The model consists of a representation using simplex meshes and a mechanical formulation of influences that drive an iterative segmentation. The object's representation as well as the influences are valid for any dimension of the image domain. The image influences introduced here, can combine information from independent channels of higher-dimensional value ranges. Additionally, the topology of the model automatically adapts to objects contained in images. Noncontextual tests have validated the ability of the model to reproducibly delineate synthetic objects. In particular, images with a signal to noise ratio of SNR /spl les/ 0.5 are delineated within two pixels of their ground truth contour. Contextual validations have shown the applicability of the model for medical image analysis in image domains of two, three, and four dimensions in single as well as multichannel value ranges.     

Yielding- and fracture behaviour of ferritic steels in the transition region of quasistatic to dynamic loading

This paper presents results of investigations on the influence of loading rate on yielding and fracture behaviour of ferritic steels. The range of loading rates was below a certain level at which a special stress wave analysis is required. Concerning the yielding behaviour it was found, that the yield strength can be predicted by the model of thermally activated flow. The strain hardening dσ/dε appeared to be independent of strain rate, if adiabetic heating can be neglected. Concerning the fracture behaviour it is demonstrated that the K_lc-T-curves are shifted to higher temperatures with increasing loading rate. The temperature shift could be correlated with the strain rate sensitivity m = d lnσ/d lnε. The ductile/brittle transition temperature increases with incrasing loading rate. For the upper shelf region crack resistance curves as a function of loading rate are presented. It is shown that the crack length can be determined using the key-curve-method. A slightly increasing tendency of the evaluated J_R-curves was found.     

A Shortcut Method for Estimating the HETP of Structured Packed Distillation Columns at Elevated Pressure

A shortcut model is developed for predicting the HETP of a structured packed distillation column operating at elevated pressure. The proposed model incorporates the geometrical parameters of the packing, physical properties of the vapor and liquid phases, and the hydrodynamics of the two‐phase flow. The proposed model is tested and validated by comparing the predicted results with the present experimental data and some published HETP data. The results show that the proposed model can predict the experimental data with a deviation smaller than 20 %.     

The effects of leukotrienes C4 and D4 on ciliary activity of human paranasal sinus mucosa in vitro

The effects of leukotrienes C4 and D4 on ciliary activity of human paranasal sinus mucosa were investigated in vitro. Normal mucosa was surgically obtained from human paranasal sinuses and incubated in the form of tissue culture. Ciliated cells were magnified under an inverted microscope, and ciliary activity was photoelectrically measured. LTD4 progressively inhibited ciliary activity, and showed a more potent effect on ciliary activity compared to LTC4. The concentrations of LTC4 and LTD4 in the incubation medium were determined by radioimmunoassay when the mucosa was incubated with 10(-8) M LTC4. The concentration of LTD4 gradually increased and after 90 min reached the maximum of 0.71 x 10(-8) M, while that of LTC4 was reduced to about 10% of its initial concentration within 60 min. These results suggested the possible conversion of LTC4 to LTD4 on the mucosa, and that LTC4 can inhibit ciliary activity by means of LTD4.     

Prognostic value of nocturnal pulse-oximetry in patients with chronic obstructive pulmonary disease treated with oxygen at home

Guaiac tests for faecal occult blood are used for colorectal neoplasia screening. Specificity may be improved by using an immunochemical test for human blood. We evaluated and compared, within an endoscopic study, an immunochemical test for human stool albumin, BM-Test Colon Albumin, with the guaiac test, Hemoccult SENSA. Both tests were given to 527 screenees who had had a low-peroxidase diet before and during the tests. All had a colonoscopic (59%) or flexible sigmoidoscopic (41%) examination. Both tests were easy to perform and develop. They were of similar sensitivity (35-30%) for adenomas > or = 1.0 cm in diameter or cancers, but Colon Albumin had a higher specificity (90%) than Hemoccult (85%; P < 0.05). The latter, however, had a higher sensitivity for neoplasia of all sizes (25% vs 20%; NS) but lower specificity (85% vs 90%; P < 0.05). Colon Albumin was positive in 11.2%, while Hemoccult SENSA was positive in 16.7% and appears very sensitive to dietary peroxidases. Positivity was reduced to 7% by changing the methodology protocol. Overall, the guaiac test is more sensitive but less specific than the immunochemical test for colorectal neoplasia. However, the technical and diagnostic limitations of these tests must be appreciated, and because of their high positivity rate neither is suitable for mass screening. A more specific test for neoplasia is needed.     

Spontaneous platelet activation and aggregation during obstructive sleep apnea and its response to therapy with nasal continuous positive airway pressure. A preliminary investigation

STUDY OBJECTIVE: To determine whether alterations of platelet reactivity occur during obstructive sleep apnea (OSA) and, if so, whether therapy with nasal-continuous positive airway pressure (N-CPAP) alters this reactivity. DESIGN: Patients with suspected moderate to severe OSA had blood drawn for spontaneous platelet aggregation (sAGG) and activation (sACT) measurements at hourly intervals during diagnostic polysomnography (PSG) and, in those with confirmed OSA, on a separate night during which N-CPAP was applied. SETTING: Tertiary care center sleep laboratory. PATIENTS: Six patients with OSA had matched blood samples drawn on both diagnostic and N-CPAP treatment nights. Five patients without confirmed OSA served as controls. INTERVENTIONS: N-CPAP was applied to those patients with OSA and pressures adjusted with goals of eliminating apneas; N-CPAP was then maintained through the night. MEASUREMENTS AND RESULTS: sACT and sAGG were measured using flow cytometric determination of P-selectin expression using a monoclonal antibody. Platelet aggregation was assessed by measuring the proportion of platelets larger than resting platelets by light scatter techniques. Mean values for sACT and sAGG were higher on the diagnostic night compared with treatment night (p = 0.001 and p = 0.003, analysis of variance, respectively). The mean baseline supine sACT compared with completion supine sACT for both diagnostic and N-CPAP nights also revealed significant differences (mean = 16.6 +/- 3.5% vs 36.9 +/- 7.5%, p = 0.04; and 11.9 +/- 3% vs 39.5 +/- 9.1%, p = 0.04). Platelet activation during sleep in five subjects without OSA resembles that found in patients with OSA during N-CPAP. CONCLUSIONS: Increased platelet sACT and sAGG occur during sleep in patients with OSA. This effect is greatly reduced by N-CPAP.     

Y Zeolite as a component of catalysts for hydrotreating petroleum fractions

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 7–12, March, 1991.