Highly Crosslinked Polysilane–Schiff Base

Summary N,N-Bis(4-hydroxysalicylidene)ethylendiamine (salen) was attached to a poly[iodopropyl(methyl)-co-diphenylsilane)chain. Due to intermolecular crosslinking reactions, a high molecular weight polymer formation was observed. The resulted material was doped with metal cations through complexation reactions. The chemical structure of the polysilane-Schiff base metal complex was investigated by spectral analysis (IR, ¹H-NMR, ¹³C-NMR, UV), thermogravimetric analysis (TGA) and gel permeation chromatography (GPC).     

Evaluation of Transport Capacity through Liquid Membranes of Some Crown Ether‐Siloxane Copolymers

The complexation ability of some linear crown ether‐siloxane copolymers of ester or amide type with cations as K⁺ and NH₄⁺ was investigated spectrophotometrically in order to select the polysiloxane receptors that achieve good ion transport ability by bulk liquid membrane systems. The transport properties of the potassium picrate through a liquid membrane using siloxane‐crown ether polyamide as carrier were discussed.     

Histopathologic and immunohistochemic correlations in virus B chronic hepatitis

Complete diagnosis of chronic hepatitis relies on exploring the liver by bipsic punction, performing the classic histopathologic and immunohistochemic exams. We worked out viral antigens hepatocytes by using avidin-biotin-peroxidase complex technique as following: Ag HBs placed in cytoplasm or at the level of the cell membrane. Ag HBc preferably placed in nucleus and, a small part of it, in cytoplasm. Ag HD present especially in nucleus. A correlation between tissular antigen expression and hepatic histopathologic aspect was established. Two main types of viral expression were remarked: a regressive type reflected by cytoplasmatic Ag HBs in the absence of generalised nuclear Ag HBc--situations linked to persistent chronic hepatitis: an aggressive type characterised by the presence of the focal nuclear Ag HBc, cytoplasmatic Ag HBc or antigen HD--situations linked to active chronic hepatitis with various degrees of severity.     

Calcifying odontogenic cyst: report of two cases and review of literature

The "Histological Typing of Odontogenic Tumours" (W.H.O., 1992) classified the Calcifying Odontogenic Cyst (C.O.C.) into two variants: the non-neoplastic cystic C.O.C. and the odontogenic ghost cell tumour, which is predominantly solid. We reported two cases of C.O.C.: a case with intraosseous development and another with extraosseous localisation, in the soft tissue of the alveolar area. The first case represents a cyst delimited by a squamous, non-keratinized epithelium, thickened in some areas through the accumulation of ghost cells (big pale-staining cells with a non-staining nuclear area). The connective tissue wall contains small ameloblastoma like islands. Dysplastic dentine islands, adjacente to the basal layer of the epithelium or in the connective tissue wall were also observed. The second case was a well-delimitated tumour consisting of ameloblastoma-like islands with numerous ghost cells inside. Islands of dysplastic dentine with psammomathous calcifications also exist. In certain histological sections microcystic aspects surrounded by ghost cells, dentinoid and ameloblastoma-like structures were noticed. The histochemical reaction for keratin and the immunohistochemical reaction for epithelial membrane antigen and for citokeratin were positive for ghost cells, suggesting their epithelial origin. Through this article we try to render pathologists sensitive with a particular and rare maxillary tumour.     

Detection of toluene dissolved in water by using PCS fibers excited by an inclined collimated beam

This paper reports results on the sensitivity of straight polymer-clad silica (PCS) detection fibers with short sensing parts coated with polysiloxane polymers to toluene dissolved in water. The detection was based on refractive index changes of the polymers induced by the penetration of toluene into them. These changes were detected by measuring changes of the output power from the detection fibers excited by an inclined collimated beam at 630 nm.

Commercially available Cablelite 950-701 and two types of polymethylphenylsiloxane polymers developed at the Romanian Academy were tested as materials for the fabrication of the detection part in the fiber cladding. These parts were prepared by application of polymer layers onto a bare silica core by a dip-coating technique. Layers with thicknesses of about 20 μm were prepared.

Examples of angular distributions of the output power determined for the detection polymers in contact with air, time response curves measured with the detection parts brought into contact with aqueous solutions of toluene under different hydrodynamic conditions, and sensitivity curves are shown in the paper. The best detection limit of about 10 mg/l of toluene, reversibility and linearity of the fiber response in a range 0–100 mg/l could be achieved with fibers coated with Cablelite 950-701 polymer.     

Influence of heat exposure on the cerebral metabolism in infant rats

Studies carried out on 96 Wistar newborn rats led to the following conclusions: the chronic exposure to heat (+40 degrees C), 10 min. daily, starting with day 1, induces a significant stimulation of 32P-incorporation into brain phospholipids (in 7-, 14-, and 21-day-old rats), into phosphoproteins (especially 14 days after birth), and into RNA and DNA (during the first 3 weeks after birth). The hypothalamic 32P-uptake is enhanced in 7- and 14-day-old rats. The authors discuss the biological significance of these findings.