Detection of optic disc in retinal images by means of a geometrical model of vessel structure

We present here a new method to identify the position of the optic disc (OD) in retinal fundus images. The method is based on the preliminary detection of the main retinal vessels. All retinal vessels originate from the OD and their path follows a similar directional pattern (parabolic course) in all images. To describe the general direction of retinal vessels at any given position in the image, a geometrical parametric model was proposed, where two of the model parameters are the coordinates of the OD center. Using as experimental data samples of vessel centerline points and corresponding vessel directions, provided by any vessel identification procedure, model parameters were identified by means of a simulated annealing optimization technique. These estimated values provide the coordinates of the center of OD. A Matlab prototype implementing this method was developed. An evaluation of the proposed procedure was performed using the set of 81 images from the STARE project, containing images from both normal and pathological subjects. The OD position was correctly identified in 79 out of 81 images (98%), even in rather difficult pathological situations.     

Cathepsin D serum mass concentrations in patients with hepatocellular carcinoma and/or liver cirrhosis

Cathepsin D serum mass concentrations were determined by enzyme immunoassay in patients with hepatocellular carcinoma (n = 51) and/or liver cirrhosis (n = 92) or benign steatosis (n = 16) and correlated with some biochemical and clinical properties of these diseases. Increased cathepsin D serum mass concentrations (P < 0.001) were observed in all these groups of patients as compared to normal subjects (n = 98). However, patients with steatosis had serum mass concentrations of this enzyme significantly lower (mean 2-3 fold) than those measured in cancer patients (P < 0.05) or cirrhotic patients (P < 0.001). Interestingly, significantly higher cathepsin D serum mass concentrations (mean + 62%) (P < 0.006) were determined in the cirrhosis group as compared to cancer patients. No correlation between cathepsin D and a number of clinical and biochemical properties examined, namely, alpha-foetoprotein, number of neoplastic lesions and tumour size in cancer patients or, Child-Pugh grade of severity of cirrhosis and other enzymes of liver function tests in the cirrhotic group was found. The present data and those from other studies which indicate that cathepsin D may be involved in carcinogenesis suggest that this enzyme may be potentially useful as an additional biochemical marker to identify cirrhotic patients who may develop precancerous hepatic nodules.     

An On-Line Pneumatic Cigarette Inspection Device Based on Two Tightly Coupled Microprocessors

Ventilation is a technique for controlling the amount of both nicotine and tar delivered to smokers. VECOM is a system designed to control cigarette ventilation. It operates on every cigarette, on-line with the production process, taking measurements in accordance with a pneumatic model of ventilated cigarettes. Presented are the problems associated with performing on-line measurements, error correction, and overall system organization.     

Prevention of hemorrhage and dental treatment of patients with congenital or acquired coagulopathies

The physiopathology of the hemorrhagic blood coagulation disorders caused by genetic or aquired problems is described. Among the former the most frequent ones include the hemophilia of type A-B and the von Willebrand disease, among the latter the use of oral anticoagulant constitutes the most frequent cause. If the are not subjected to an adequate haemostatic prophylaxis, both patients with hemophilia and von Willebrand disease present a serious haemorrhagic risk as a consequence of dental practice. As far as the use of anticoagulants is concerned, a periodical monitoring of the time of prothrombin (PT) is needed to find the right dosage (TP between 20%-30% or INR--international normalized radio between 2 and 3.5). Values over this range cause an increase of the hemorrhagic risk, while lower values involve an increased risk of thrombotic events. According to the authors the patients with the hemorrhagic diathesis show a precise handicap, caused both by his illness and by environmental elements, such as the fear of doctors for the haemorrhagic complications consequent to a therapeutical operation, fear that often leads to neglect important medical measures, in particular dental measures. The specialized dental surgeon has to mantain a strict cooperation with the hematologist in order to arrange an appropriate procedure of the prophylaxis. As far as the hemostatic prophylaxis is concerned, the use of the dermopressin (DDAVP), in patients with hemophilia A and von Willebrand disease, guarantees the realisation of dental practice without hemorrhagic risk. On the contrary, the use of the tranhexanic acid on patients in an anticoagulant oral treatment gives hemostatic security and makes it possible to carry on the therapy and the out-patient treatment.     

Optimal Design of Multioutput Sampling Schedules?Software and Applications to Endocrine?Metabolic and Pharmacokinetic Models

This paper describes a program for computing optimal sampling schedules for multiinput-multioutput experiments designed for parameter estimation of physiological systems models. Theory of the algorithm and details of its implementation are given. Practical applications of the software to models of glucose-insulin regulation, ketone body, and insulin kinetics are presented. Results document the potentiality of the software for designing experiments, and show that optimal design can considerably reduce the number of samples withdrawn from a patient in in vivo clinical studies.     

High temperature distillation process with sea water feed decalcification pretreatment

The performance ratio of a desalination plant can be increased to reach 16–18 by coupling it with a decalcification pretreatment by ion exchange of the sea-water make-up, so making MSF comparable with RO from energetic point of view. A new strong cationic resin DECAL has been tailored; its main features are high selectivity towards the calcium ion and low concentration of the regenerating brine. These characteristics make it compatible with the normal operating range of multiflash plants and very suitable for the above service, when compared with other resins.The optimum coupling conditions of the whole plant, as has been pointed out, lie between 140°C and 150 °C for the top brine temperature and 2 to 2.5 for the brine concentration factor. In these conditions it is possible to operate with sea water-resin bed ratio higher than 20.     

Chemical kinetics and diffusion in poly(butylene terephthalate) solid-state polycondensation: Experiments and theory

Postpolymerization was obtained in solid PBT sheets, by annealing in a dry nitrogen stream at 214°C. After different reaction times, the samples were cut into thin slices. The M_w profile within the sample was obtained through intrinsic viscosity measurements in a phenol–TCE mixture. At each location inside the sample, the [η] vs. time curve typically shows a maximum, which is rather broad at the midplane and much sharper at the external surface. The phenomenon was mathematically described by accounting for both diffusion and chemical reactions within the slab; five simultaneous chemical reactions have been considered. The observed behavior is found to be essentially due to two competing processes, i.e., the diffusion of the low molecular weight species generated during the polycondensation and the thermal degradation reaction. The model predictions are compared with the experimental data showing a satisfactory agreement.     

1-GHz GaAs ADC building blocks

GaAs ICs for high-speed, 6-b, 1G-sample/s (Gs/s) data acquisition are under development, using a low-cost conventional D-MESFET technology. First-generation sample-and-holds (S/Hs) and comparators are currently being sampled to customers. Diode-bridge and FET-switch S/Hs have been compared. Best performances have been achieved with diode-bridge switches: 1 ns and 6 bits. Comparators provide 6-b sensitivity at 1 GHz, but require offset adjustments. Second-generation analog-to-digital converter (ADC) building blocks have been made. Performances and applications of resulting circuits as well as advanced ADC design criteria are discussed, with special attention to yield. First results on a 4-b ADC are presented     

Book Embeddability of Series–Parallel Digraphs

In this paper we deal with the problem of computing upward two-page book embeddings of Two Terminal Series-Parallel (TTSP) digraphs, which are a subclass of series-parallel digraphs. An optimal O(n) time and space algorithm to compute an upward two-page book embedding of a TTSP-digraph with n vertices is presented. A previous algorithm of Alzohairi and Rival [1] runs in O(n³) time and assumes that the input series-parallel digraph does not have transitive edges. An application of this result to a computational geometry problem is also discussed. More precisely, upward two-page book embeddings are used to deal with the upward point-set embeddability problem, i.e., the problem of mapping planar digraphs onto a given set of points in the plane so that all edges are monotonically increasing in a common direction. The equivalence between upward two-page book embeddability and upward point-set embeddability with at most one bend per edge on any given set of points is proved. An O(n log n)-time algorithm for computing an upward point-set embedding with at most one bend per edge for TTSP-digraphs is presented.     

A program for the optimization of cyclosporine therapy using population kinetics modeling

Cyclosporine is one of the most widely used immunosuppressive agents in organ transplantation. Due to large inter- and intra-individual variations, its behavior in the specific patient is still difficult to predict. Dosage optimization is thus mainly performed on a trial-and-error basis. In this paper, we present a new program based on the population kinetics approach, which was designed to help physicians in the difficult task of adjusting patient specific cyclosporine dosing regimens. Dose optimization is carried out by model simulation, using a two-compartment mathematical model of cyclosporine kinetics to predict the drug behavior in the patient. Two of the model parameters are assumed from the literature, the other two are estimated from the patient data through a Bayesian estimation procedure. Previous information needed by the Bayesian algorithm is derived by a population analysis, performed beforehand and based on a nonlinear mixed effect model. A user-friendly graphical interface written in Delphi under Windows makes the program easily accessible to physicians. A preliminary retrospective validation of the program, performed on data from 18 renal transplanted patients, yielded very satisfactory results.