Diagnostic captioning: a survey

Knowledge and Information Systems - Diagnostic captioning (DC) concerns the automatic generation of a diagnostic text from a set of medical images of a patient collected during an examination. DC...     

Interleukin 1 beta synergises with interleukin 2 in the outgrowth of autologous tumour-reactive CD8+ effectors

Using peritoneal fluid or pleural effusion obtained from 20 patients with lung, ovarian or metastatic breast cancer, we separated tumour cells from malignant effusion-associated mononuclear cells (MEMNCs) using discontinuous Ficoll-Hypaque density gradients. CD3+ T lymphocytes represented the main population of MEMNCs. The mean +/- s.d. CD4/CD8 ratio of MEMNC suspensions was 1.18 +/- 0.40. MEMNCs proliferated and expanded in vitro with human interleukin 2 (IL-2) either as CD3+ CD8+ cells or as CD3+ CD4+ cells or as mixed populations of CD8+ and CD4+ cells. Preferential cytolytic activity against autologous tumour cells was demonstrated in IL-2-activated MEMNC cultures with excess CD3+ CD8+ cells. In contrast, effectors derived from IL-2-activated cultures with excess CD3+ CD4+ cells lysed both autologous and allogeneic tumour target cells. The addition on day 0 of interleukin 1 beta (IL-1 beta) to MEMNCs cultured in the presence of IL-2 was effective in promoting the growth of CD3+ CD8+ cells and augmenting the cytotoxicity against autologous tumour. Simultaneously, the production of gamma-interferon (IFN-gamma) was increased in these cultures. This is the first report suggesting that IL-1 beta synergises with IL-2 to induce autologous tumour-specific CD8+ cytotoxic T lymphocytes (CTLs) within the MEMNC population. Selective enrichment in T-cell subsets by IL-1 beta may be useful in cellular adoptive immunotherapy using cells isolated from malignant effusions.     

Geostatistical analysis of spatial variability of rainfall and optimal design of a rain gauge network

Kriging is a geostatistical estimation technique for regionalized variables that exhibit an autocorrelation structure. Such a structure can be described by a semivariogram of the observed data. The punctual-kriging estimate at any point is a weighted average of the data, where the weights are determined by using the semivariogram and an assumed drift, or lack of drift, in the data. The kriging algorithm, based on unbiased and minimum-variance estimates, involves a linear system of equations to calculate the weights. Kriging is applied in an attempt to describe the spatial variability of rainfall data over a geographical region in northern Greece. Monthly rainfall data of January and June 1987 have been taken from 20 measurement stations throughout the above area. The rainfall data are used to compute semivariograms for each month. The resulting semivariograms are anisotropic and fitted by linear and spherical models. Kriging estimates of rainfall and standard deviation were made at 90 locations covering the study area in a rectangular grid and the results used to plot contour maps of rainfall and contour maps of kriging standard deviation. Verification of the kriging estimates of rainfall are made by removing known data points and kriging an estimate at the same location. This verification is known as the jacknifing technique. Kriging errors, a by-product of the calculations, can then be used to give confidence intervals of the resulting estimates. The acceptable results of the verification procedure demonstrated that geostatistics can be used to describe the spatial variability of rainfall. Finally, it is shown how the property of kriging variance depends on the structure and the geometric configuration of the data points and the point to be estimated can also be used for the optimal design of the rain gauge network in an area.     

Large and small signal distortion analysis using modified Volterra series

A new approach to the Volterra analysis of analog circuits is presented. Volterra analysis is widely used for the calculation of harmonic and intermodulation distortion products. However, the analysis is limited to circuits experiencing small signal excitations and becomes inaccurate when the input signal amplitude increases, especially when MOS transistors are involved. In this paper, we analyze the cause of this drawback, which is no other than the Taylor series’ convergence properties. Moreover, we propose a solution, by calculating the nonlinearity coefficients using a different type of polynomial expansion, the Chebyshev series. This replacement improves significantly the capabilities of Volterra analysis. We also present results comparing Chebyshev series with other types of polynomial expansions. Finally, we apply the proposed method to analyze the intermodulation distortion (IMD) of a CMOS RF power amplifier, both in the small and the large signal regimes.     

Elevated prostaglandin E2 production by monocytes is responsible for the depressed levels of natural killer and lymphokine-activated killer cell function in patients with breast cancer

BACKGROUND: Human natural killer (NK) cells mediate spontaneous cytotoxicity against tumor cells and represent the main precursors of lymphokine-activated killer (LAK) cell activity. A comparison of some aspects of NK and LAK cell activity was undertaken in 85 preoperative patients with breast cancer and 75 healthy donors. METHODS: NK cell activity (tested in 18-hour cultures of effector peripheral blood mononuclear cells [PBMC] with K562 or MOLT-4 tumor target cells) was significantly diminished in these patients as it was the fully mature LAK cell activity (i.e., interleukin-2 (IL-2)-induced cytotoxicity in PBMC) against NK resistant target cells. Using immunoenzymatic methods we showed that the reduced NK cell activity was due to abnormally high levels of prostaglandin E2 (PGE2) produced by monocytes in culture. RESULTS: PGE2 was found to suppress the production of IL-2 in these cultures. Removal of monocytes from PBMC restored to almost normal levels the deficient NK and LAK cell activity in patients with breast cancer and was also associated with a normalization in the levels of PGE2 and IL-2. Indomethacin and gamma-interferon (IFN-gamma) increased the NK and LAK cell activity in these patients up to the levels of healthy donors. When highly purified CD56+ cells (obtained by an immunomagnetic isolation technique) were used as effector cells, no differences in LAK cell activity could be noticed between healthy donors and patients with cancer. FACS and northern blot analyses demonstrated a PGE2-mediated down-regulation of IL-2 receptor (IL-2R) expression on CD56+ cells that correlated with reduced LAK cell activity. This inhibitory effect of PGE2 was noticeable in long-term LAK cultures and was abrogated in the presence of IFN-gamma or indomethacin. CONCLUSION: This study may have important implications in the potentiation of NK and LAK cell activity for immunotherapeutic protocols in patients with breast cancer.     

Traffic-Responsive Linked Ramp-Metering Control

A new traffic-responsive ramp-metering strategy is presented that coordinates local ramp-metering actions, thus enabling the linked control of the inflow from two (or more) consecutive on-ramps to the freeway mainstream. The proposed linked ramp-metering scheme is simple and utterly reactive, i.e., based on readily available real-time measurements without any need for real-time model calculations or external disturbance prediction. The well-known feedback strategy, known as Asservissement LINeaire d'Entree Autoroutiere (ALINEA), is used at a local level. Simulation results are presented for a hypothetical freeway axis with two successive on-ramps. Some pitfalls and misapplications of the local ramp metering are also illustrated via appropriately designed simulation scenarios. The proposed linked strategy is demonstrated to outperform the uncoordinated local ramp metering and, thus, to increase the achievable control benefit over the no-control case. In fact, the new strategy is shown to reach the efficiency of sophisticated proactive optimal control schemes.     

A Misapplication of the Local Ramp Metering Strategy ALINEA

In a recent series of articles with largely identical contents and results, some claims are raised about the pertinence and performance of the well-known and widely field-applied local ramp metering algorithm ALINEA and of some extended versions thereof. The expressed claims are based on simulation results with a self-made microscopic simulator. This paper shows that the produced simulation results and derived conclusions are based on an insufficient understanding of the feedback character of the ALINEA algorithm, which led to an inappropriate application of the method. More specifically, the mainstream measurement that feeds ALINEA was misplaced so that any occurring congestion could not be monitored; this renders ALINEA blind to the traffic conditions under control and negates the very notion of feedback.     

Analytical Tools for Rapid,Sensitive, Quantitative Identification of Potential Meat Quality Markers

Myofibrillar extracts from bovine Musculus longissimus dorsi (MLD) were subjected to SDS‐PAGE, electroblotted and fragments of the 30 kDa band determined by internal and N‐terminal Edman sequencing, giving unequivocal proof, troponin‐T (TNT) to be the origin of this band. Based on the N‐terminal primary sequence of the 30 kDa band, a peptide with high antigenic sites was synthesized, conjugated to keyhole limpet hemocyanin (KLH), antibodies were generated and an enzyme‐linked immunosorbent assay (ELISA) was developed for the determination of TNT concentrations in meat samples. For routine determinations of meat quality markers it seems more convenient to analyse soluble meat extracts, produced by trichloroacetic acid (TCA) or HCl treatment. In the supernatants of TCA‐treated MLDs, prominent peptide fragments from glyceraldehyde‐3‐phosphate dehydrogenase and TNT (16—31) could be separated by HPLC and identified by Edman degradation. Both fragments were found to increase with ageing and might become useful indicators of meat quality. After HPLC separation and structure elucidation of MLD HCl extracts, fructose biphosphate aldolase, creatine kinase, glyceraldehyde‐3‐phosphate dehydrogenase and myoglobin could be identified, further potential candidates to correlate their quantitative appearance with meat quality. These peptides and proteins, found in soluble meat extracs, can be analyzed in an automatic, rapid, convenient way either by immunoassay methods, capillary electrophoreses or HPLC, for sure preferable compared to the tedious, inconvenient, time‐consuming method of SDS‐PAGE, also not suitable for automation.     

The no slot wasting bandwidth balancing mechanism for dual busarchitectures

A bandwidth balancing (BWB) mechanism has been added to the distributed queueing algorithm of the distributed-queue dual bus (DQDB) network. BWB can provide the requested throughputs by lightly loaded stations and evenly distribute the remaining channel bandwidth among overloaded stations. However, its operation requires the wastage of channel slots. The authors introduce a new bandwidth balancing mechanism for DQDB. The operation of the new mechanism requires one additional bit in the access control field (ACF) of the slot but has the advantage of exhibiting a similar behavior with the current BWB mechanism of DQDB without wasting any channel slots. For this reason, it can converge faster to the steady state in which fair bandwidth allocation is achieved. The authors investigate the throughput and delay performance of the proposed mechanism under one traffic class and examine its capacity to support multiple priority classes of traffic. They also compare its performance with the corresponding performance of the BWB mechanism of DQDB