Computer Vision and Pattern Recognition 2020

International Journal of Computer Vision -     

Surgery for hepatoblastoma in children

In order to characterize the role of transforming growth factor-alpha (TGF alpha) during hepatocarcinogenesis, liver tissue was examined at 10, 16, and 19 weeks following initial 10-week diethylnitrosamine (50 mg l-1 drinking water) exposure in female Wistar rats. Liver tissue protein extracts were electrophoresed and transferred to nitrocellulose filters. Levels of tissue-derived TGF alpha and epidermal growth factor receptor (EGFr) were assessed using an anti-TGF alpha monoclonal antibody (Ab-1) and an anti-EGFr polyclonal antibody (AB-4), coupled with scanning densitometric quantification. Immunolocalization of TGF alpha was performed in Bouin's-fixed, paraffin-embedded liver tissue sections. The distribution and intensity of TGF alpha immunoreactivity varied according to the degree of dysplasia, severely dysplastic cells being strongly immunoreactive. At week 10, mild hepatocyte dysplasia and perivenular inflammation were evident, together with a corresponding increase in perivenular TGF alpha immunoreactivity. By week 16, foci of moderate to severe dysplasia were observed; at this stage, there was a decrease in perivenular immunoreactivity but a further increase in overall liver tissue TGF alpha levels. Some 'altered foci' and dysplastic nodules showed intense immunoreactivity for TGF alpha. At these time points, immunodetectable liver EGFr was found to decrease significantly in comparison with normal control tissue. TGF alpha immunoreactivity was observed in fully developed carcinomas at week 19, although some tumours were negative by immunohistochemistry. The up-regulation of immunodetectable TGF alpha and the concomitant down-regulation of EGFr demonstrated positive (P < 0.01) and negative (P < 0.001) correlations, respectively, with hepatocyte proliferation indices. These findings suggest that the TGF alpha/EGFr ligand receptor system may be important during tumour promotion and in the stimulation of continued proliferation in hepatocellular carcinomas.     

Analysis of molecular determinants in native AMPA receptors

For this study, 194 respondents completed a biographical data sheet, the Templer (1970) Death Anxiety Scale and the Constantinople (1973) Inventory of Psychosocial Development to help assess the relationship among death anxiety, age, and psychosocial maturity. Findings showed that psychosocial maturity was a better predictor of death anxiety than age was. However, both variables were significantly negatively correlated with death anxiety, revealing that as psychosocial maturity and age increase, death anxiety decreases.     

Heat transfer at the base of a cylindrical cavity oriented perpendicular to a freestream flow

The average and local heat transfer at the base surface of a cylindrical cavity whose opening is perpendicular to an oncoming freestream have been determined experimentally. During the course of the experiments, the cavity depth was varied from zero to 65% of the diameter, while the freestream Reynolds number ranged between about 5000 and 50,000. The average heat transfer coefficient decreased sharply with increasing cavity depth, the reduction being slightly greater than 50% at a depth-diameter ratio of 0.10 and greater than 90% when the depth-diameter ratio was 0.65. For the finite-depth cavities, the local heat transfer coefficient attained its maximum value at the center of the base surface and decreased with increasing radial distance from the center until a minimum was reached, after which there was a moderate increase adjacent to the outer edge of the base. The minimum occurred at the location where the radial outflow along the base separated from the surface, and a toroidal-shaped recirculation zone occupied the corner region at the intersection of the cavity base and side wall. In contrast, for the zero-depth cavity (i.e. a free disk oriented perpendicular to the oncoming flow), the local coefficient attained its minimum at the center of the surface and increased with increasing radial distance from the center.     

Dynamic range of coherent analog fiber-optic links

We investigate the performance of coherent analog optical links employing amplitude modulation (AM), phase modulation (PM), and frequency modulation (FM). The performance of these coherent links is compared to that of AM direct-detection (DD) links. The signal-to-noise ratios, nonlinearities, and-spurious-free dynamic ranges (SFDR's) of the foregoing links are evaluated. We calculate the SFDR for links using DFB and Nd:YAG lasers with typical linewidths of 10 MHz and 5 kHz, respectively. The performance of PM and FM links is dominated by phase noise above a critical value of received optical power. For a linewidth of 10 MHz, and SFDR's of PM and FM links are 30 and 31 dB, respectively, for a received optical power above -27 dBm in a 1 GHz bandwidth. For a linewidth of 5 kHz, the corresponding SFDR's above a received power level of 0 dBm are 51 and 53 dB. The performance of DD and AM links is dominated by RIN above a critical value of received optical power. For a RIN level of -155 dB/Hz, the SFDR's of DD and AM links are 49 and 47 dB, respectively, for a received optical power of 10 dBm in a 1 GHz bandwidth. The SFDR's of the DD and coherent links used for transmission of subcarrier-multiplexed (SCM) signals are also derived. We evaluate target laser parameters needed by a number of different applications. For AM video and antenna remoting applications, linewidths of <1 and <3 kHz are required to use PM and FM links, respectively. For FM video, linewidths of <150 and <350 MHz are required to use PM and FM links. For SCM digital applications, linewidths of <80 and <200 MHz are required to use PM and FM links. The paper concludes with a discussion of system implementation issues, including linearization, optical frequency modulation, balanced receivers, and IF issues     

A novel laboratory bench for practical evaluation of catalysts useful for simultaneous conversion of NOx and soot in diesel exhaust

This study deals with the development of a laboratory bench for the practical evaluation of catalysts that are useful for the direct conversion of NO_x and soot in the exhaust of diesel engines. The employed model exhaust is generated by using a diffusion burner with additionally dosing some gaseous components to the burner gas to obtain a realistic feed composition. The produced soot is extensively characterized by employing thermogravimetry, transmission electron microscopy, N₂ physisorption and temperature programmed techniques. The results of the different characterization methods show that the present soot is suitable for the intended catalytic investigations. The simultaneous conversion of NO_x and soot is examined like in practice, i.e. the soot is separated from the tail gas by a diesel particulate filter (DPF) that is coated with the catalyst. The deposited soot is then catalytically converted by NO_x and O₂ to form N₂ and CO₂. The conversions of NO_x and soot are measured by exclusively applying gas analysers, whereby a special experimental procedure is developed to determine the soot removal. Hence, additional soot related analytics are not required. To show the suitability of the constructed bench a Pt/Fe₂O₃/β-zeolite sample is taken as test catalyst that is reported to be very active in NO_x/soot reaction. The measurements performed with and without catalyst clearly show the effect of the used sample in simultaneous NO_x/soot conversion. We therefore consider the constructed laboratory bench to be a useful tool for testing and ranking catalytic materials.