Fabrication and characterization of planar and channel polymer wave guides. I. Plasma-polymerized HMDS films

Plasma-polymerized hexamethyldisiloxane (HMDS) films have been prepared as both planar and channel wave guides. The optical attenuation results measured in both the planar and channel HMDS wave guides were found to be similar, thus demonstrating that the inherent solvent resistance and chemical inertness of the plasma polymerized films allows the use of common photoresist techniques, including application of the photoresist, photomasking, and subsequent etching. This may be contrasted with wave guides made from conventional polymers, where careful consideration must be given to photoresist/polymer compatibility, because the photoresist solvents may adversely affect the underlying polymer and lead to degradation of the material during processing. © 1995 John Wiley & Sons, Inc.     

Chronic abdominal pain: role of video-laparoscopic adhesiolysis

Adhesions have been suggested as a possible cause of chronic abdominal pain, but the reports of their etiological role conflict. Lysis of adhesions has been proposed as the therapeutic modality of choice, although the reports of success are controversial. The aim our prospective study was to determine whether laparoscopic adhesiolysis ameliorates chronic abdominal pain in patients with abdominal adhesions. Forty-one patients with chronic abdominal pain lasting for more than 6 months, but with no abnormal findings other than adhesions found at laparoscopy, underwent laparoscopic adhesiolysis. 37 patients (90.2%) were available for follow-up after a median time interval of 18 months (range: 12-41 months). Twenty-two patients (59.4%) were free from abdominal pain and 9 (24.3%) patients reported significant amelioration of their pain. Six (16.2%) patients had no amelioration. In conclusion the laparoscopy is an effective tool for the evaluation of patients with chronic abdominal pain, and laparoscopic adhesiolysis cures of ameliorates chronic abdominal pain in more than 80% of patients.     

A new epitope presenting system displays a HIV-1 V3 loop sequence and induces neutralizing antibodies

The principal neutralizing domain, IGPGRAF sequence, from the V3-loop of HIV-1 was inserted in two positions on the surface of the protein that makes up the capside shell of the insect Flock House Virus. The hybrid proteins were expressed in insect cells via recombinant baculoviruses. Three different hybrids were used as immunogens: two with a single copy of the insert in different positions of the carrier protein and a third with two copies of the insert at the same positions as before. All hybrid proteins induced strong and broad specific immune response in guinea pigs against different V3-loop sequences. However, only one of the hybrid proteins was able to induce a strong neutralizing response against MN and IIIB HIV-1 isolates. Our results demonstrate that a very short peptide sequence of HIV-1 can constitute a valuable immunogen able to induce a neutralizing response if presented to the immune system in the context of the FHV capsomer structure.     

How do the newer oral antimicrobials stack up against traditional agents?

As the antibiotic arsenal expands with the development of new oral agents, selecting appropriate therapy is becoming more difficult. What are the therapeutic indications for the newer antimicrobials, and what advantages do they have over traditional agents? Drs Gleckman and De La Rosa discuss current issues related to antibiotic treatment and offer specific recommendations for the best use of the newer agents.     

Human neonatal ovary: proposal of a three-dimensional model

A model of human neonatal ovary is presented, derived from morphometric, evaluations carried out on left ovaries removed from five full-term neonates with a 46, XX karyotype, free from malformations of the genital apparatus. According to this model, the gonad can be represented by a triaxial ellipsoid with a central medullary core surrounded by a cortical stratum of constant thickness. The germinal population, consisting of follicles and primitive cortical tissue, occupies the cortex, intermingled with the interstitium or stroma. In the cortex it is then possible to describe an outer layer formed by primitive cortical tissue, and an inner portion occupied by follicles. The primary and secondary follicles fill the portion near the medulla and the primordial ones are contained in the middle and outer zones. Since the variability observed among ovaries is slight, we can propose a mean model of neonatal ovary in which the spatial relationships among the different components, the total number of follicles and their position in the cortex can be calculated.     

Giant cell myocarditis. Report of a case

The authors report a case of giant cell myocarditis leading to rapidly progressive cardiac failure despite immuno-suppressor treatment in a 20 year old woman. The cardiac failure was successfully managed by implantation of a left ventricular assist device and then cardiac transplantation. The problems encountered underline the importance of accurate diagnosis by endomyocardial biopsy before undertaking treatment and the difficulties in the choice of appropriate method of assistance in this indication. Giant cell myocarditis is a rare cause of cardiac failure and should be considered in the differential diagnosis in view of its clinical features and risk of progression. The literature and the therapeutic implications are discussed.     

A method for improving classification reliability of multilayerperceptrons

Criteria for evaluating the classification reliability of a neural classifier and for accordingly making a reject option are proposed. Such an option, implemented by means of two rules which can be applied independently of topology, size, and training algorithms of the neural classifier, allows one to improve the classification reliability. It is assumed that a performance function P is defined which, taking into account the requirements of the particular application, evaluates the quality of the classification in terms of recognition, misclassification, and reject rates. Under this assumption the optimal reject threshold value, determining the best trade-off between reject rate and misclassification rate, is the one for which the function P reaches its absolute maximum. No constraints are imposed on the form of P, but the ones necessary in order that P actually measures the quality of the classification process. The reject threshold is evaluated on the basis of some statistical distributions characterizing the behavior of the classifier when operating without reject option; these distributions are computed once the training phase of the net has been completed. The method has been tested with a neural classifier devised for handprinted and multifont printed characters, by using a database of about 300000 samples. Experimental results are discussed.