Three different criteria for the design of two-dimensional zerophase FIR digital filters

An error criterion for the design of FIR filters is proposed. Filters with relatively many free filter coefficients are designed using the Chebyshev, the weighted-least-squares (WLS), and a new partitioned minimax error criterion, and the performance of the filters is compared. A general and fast technique for the WLS design is also presented     

Does psychosocial intervention in cancer patients affect survival and psychological well-being?]

We have critically reviewed the scientific literature examining the effect of psychosocial interventions on survival and well-being among adult cancer patients. Only studies using randomization and including a control-group not receiving psychosocial intervention were reviewed. Six studies examined the effect on prognosis. In four of these studies survival increased significantly in the intervention group as compared to the control group. All of these studies, however, have methodological flaws, leaving a possible prognostic effect to be clarified in larger, well-controlled future studies. The effect of psychosocial intervention on various psychosocial variables (such as anxiety and depression) was evaluated in 20 studies. Differences in patient populations, intervention strategies, and outcomes decrease the comparability of the results, and the majority of these studies suffer from methodological flaws as well. A positive effect on anxiety and depression immediately following the intervention is, however, reported in the majority of these studies. It is thus possible that the level of anxiety and depression may be decreased by integrating psychosocial intervention in the overall treatment of cancer.     

On convergence proofs in system identification – a general principle using ideas from learning theory

It is shown that learning theory offers convergence analysis tools that are useful in system identification problems. They allow analysis in a parameter-free context, which elevates the analysis from parameter sets to model sets and from parameter identification to model identification. When a parameterization is eventually introduced, this leads to alternative assumptions on the parameterization and parameter set. Moreover, structural identification can be analyzed within the same framework. Another advantage is that the proofs are technically and conceptually simple.     

Mechanism for enhanced external transfer of dimeric IgA over pentameric IgM: studies of diffusion, binding to the human polymeric Ig receptor, and epithelial transcytosis

Transport of polymeric Igs (pIgA and pIgM) across secretory epithelia is mediated by the polymeric Ig receptor (pIgR), also known as the transmembrane secretory component. Compared with local production, external transfer of pIgA is favored 6- to 12-fold over that of pIgM on a molar basis. This transfer may be modulated at several levels: diffusion through matrix and basement membranes, ligand affinity for pIgR, and efficiency of epithelial transcytosis. To investigate these possibilities, we compared the ability of Madin-Darby canine kidney epithelial cells transfected with human pIgR to transport pIgA vs pIgM from the basolateral to the apical face, and examined the inhibitory effect of various filter types used for mounting of the monolayer. Binding data showed that pIgR bound pIgA and pIgM with similar affinity. Internalization of both ligands was fast and took place at similar rates; transcytosis was also found to be equally efficient at the molar level. Thus, the overall rate of transport across the epithelial monolayer was comparable for pIgA and pIgM, and was not further enhanced by ligand stimulation over a 20-fold increased concentration level. Conversely, pIgA had a considerable advantage over pIgM in passive diffusion assays performed in vitro. Moreover, in situ immunofluorescence staining showed retention of IgM over IgA and IgG in mucosal basement membrane zones, in contrast to the preferential epithelial uptake of IgA and, less so, IgM. The biologic consequences of the highly efficient epithelial pIg transport, and the diffusion advantage of pIgA over pIgM, are discussed in relation to the evolution and function of secretory Abs.     

Mesocosm study of Mytilus edulis larvae and postlarvae, including the settlement phase, exposed to a gradient of tributyltin

In a mesocosm study, the effects of a gradient of tributylin (TBT) (nominal TBT concentrations of 0.3, 2.3, 18.5, 146, and 1150 ng Sn liter-1) on Mytilus edulis larvae and postlarvae, including the settlement phase, were investigated over 15 days. Effects of TBT on mortality, growth measured as increase in shell length, shell dimensions, and settlement were evaluated. In general, mortality was high in all mesocosms including the control; during the first 24 h of the experiment, mortality was 63% at the highest TBT concentration (26% in the control). An LC50 (24 h) of 254 ng Sn liter-1 was estimated. The mortality rate of larvae/postlarvae increased 40% at 18.5 ng Sn liter-1 (0.41 day-1) compared with the control (0.30 day-1). For postlarvae, the growth rate decreased with increasing TBT concentration. The mean shell length at 2.3 ng Sn liter-1 was significantly reduced in comparison to the control on Day 15. Then EC10 (15 days) for shell growth was estimated to be 5.4 ng Sn liter-1. This is the lowest effect concentration ever reported in the literature. For postlarvae, shell dimensions in terms of shell length-shell width relations were affected by TBT at 1150 ng Sn liter-1, because the reduced growth led to the failure of adult mussels to secret a dissochonch shell. During the first days of exposure, the settlement monitored on polyethylene settling strips was stimulated by TBT, after which the settlement decreased due to the high mortality. Only a small portion of the population survived to the end of the test period. By comparison of the biotic conditions (in terms of larval abundance and particle concentration reflecting larval food) in the control mesocosm with those in the cove where the experiment was conducted, it was concluded that the mesocosm had successfully simulated the field conditions.     

Venous thromboembolism--incidence and risk factors in Oslo

Over a period of three years, 378 patients with objectively verified venous thromboembolism were treated at Aker University Hospital. Below the age of 60, men and women had about the same incidence of venous thromboembolism, but that age the incidence was significantly higher among men than among women. Incidence increased exponentially with age, from about 1:10,000 at age 20 to about 1:1,000 at age 50. The incidence found here is lower than in earlier Nordic studies. The great majority of the patients (93%) had deep venous thrombosis in the lower extremities, 11% had symptomatic and verified pulmonary embolism, and 1% had their thrombus in an inner organ vein. 23% of patients were previously treated for venous thromboembolism, and 22% had cancer. Seven women were on oral contraception, and 22 used postmenopausal hormone substitution. An obvious temporary precipitating factor was present in 42% of the patients, while 36% had a spontaneous venous thromboembolism. Hereditary thrombophilic disorder was found in 32% of patients below the age of 60.     

High-resolution computer tomography of the lungs

High-resolution CT (HRCT) is a technique developed over the last decade. It optimises spatial resolution and provides details similar to those obtainable from gross pathologic specimens. HRCT of the lungs provides an accurate assessment of the pattern and distribution of many disease processes that in the conventional chest radiograph are occult or non-specific. HRCT is an established technique and the method of choice for evaluating a variety of pulmonary diseases. In this review we describe the modifications in CT technique that are instrumental in obtaining HRCT, and we also give examples of normal and pathologic findings in general.     

Hydrogenation of fatty acid methyl esters to fatty alcohols at supercritical conditions

Extremely rapid hydrogenation of fatty acid methyl esters (FAME) to fatty alcohols (FOH) occurs when the reaction is conducted in a substantially homogeneous supercritical phase, using propane as a solvent, over a solid catalyst. At these conditions, the limitations of hydrogen transport are eliminated. At temperatures above 240°C, complete conversion of the starting material was reached at residence times of 2 to 3 s, which is several orders of magnitude shorter than reported in the literature. Furthermore, formation of by-products, i.e., hydrocarbons, could be prevented by choosing the right process settings. Hydrogen concentration turned out to be the key parameter for achieving the above two goals. As a result of the supercritical conditions, we could control the hydrogen concentration at the catalyst surface independently of the other process parameters. When methylated rapeseed oil was used as a substrate, the hydrogenation catalyst was deactivated rapidly. However, by using methylated sunflower oil, a catalyst life similar to that obtained in industrial processes was achieved. Our results showed that the hydrogenation of FAME to FOH at supercritical conditions is a much more efficient method than any other published process.     

Computer-Based Teleconferencing: Effects on Working Patterns

Working with others via computer terminal facilitated information exchange but created other psychological barriers.     

Surface activation of carbon film supports for biological electron microscopy

The effect of glow-discharging on maked carbon-filmed grids has been evaluated. The effect of different locations of the grids within a DC discharge, operated in the normal glow, was analyzed by applying various biological specimens to the grids. Two locations were found to give consistent results: (a) in Crookes dark space, particulate specimens, negatively stained, spread evenly — suggesting a net negative surface charge of the support; (b) below the anode, nucleic acids, selectively (positively) stained, appeared as well spread filaments, indicating a net positive surface charge.