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Hybrid biocomposite scaffolds (HBS) that serve as a carrier for cell proliferation and differentiation are increasingly used for tissue regeneration. 3D hybrid scaffold based on collagen-grafted-chitosan-glucan fiber (CO-g-CGF-HBS) was prepared by freeze-drying technique. The swelling percentage, hydrolytic stability, and modulus of elasticity of HBS were enhanced after the chemical modification of CO with CGF. Pore size and porosity of HBS were decreased with an increased CGF ratio. HBS exhibits a higher reduction rate against different types of bacteria compared with a control sample. Thus, chemical modification of CO with different ratios of CGF significantly improved the physicochemical, antibacterial properties of HBS.

The growing interest in biodegradable products paves the way for the safest sustainable earth. Starch is an extensively studied, cost-effective, easily accessible, and highly trusted resource to produce biodegradable products in the present and future. However, the exploitation of these starch in several fields requires substantial changes in its chemical functionalities and related properties. Here, we investigated the conditions (pH, temperature, the concentration of starch, concentration of chloroacetate, time, the ratio between starch/sodium hydroxide, etc.) that affect the preparation of carboxymethyl starch (CMS). The chemical structure and degree of substitution of native starch and CMS were confirmed by Fourier transform infrared ( FTIR), X-ray powder diffraction (XRD), Thermogravimetric analysis (TGA), potentiometric titration, Scanning electron microscope (SEM), and Nuclear magnetic resonance spectroscopy (NMR ). CMS's rheological properties show that CMS's intrinsic viscosity increased with increased degrees of substitutions (DS) from CMS (0.05 to 0.45). The CMS with different DS (0.05 to 0.45) was used for the first time to stabilize selenium nanoparticles (Se-NPs), showing spherical shape with a high homogenous size of Se-NPs (approx. 50 nm). The NPs shape and size stability were investigated and confirmed by different techniques like Dynamic light scanning (DLS), SEM, and Transmission electron microscope (TEM)

In fiber reinforced composites (FRCs), exhibiting heterogeneous structure at multiple length scales, the interphase phenomena at various length scales were shown to be of pivotal importance for the control of the performance and reliability of such structures. Various models based on continuum mechanics were used to describe effects of the macro- and meso-scale interphase on the mechanical response of laminates and large FRC parts, satisfactorilly. At the micro-scale, the interphase is considered a 3D continuum with ascribed average properties. Number of continuum mechanics models was derived over the last 50 years to describe the stress transfer between matrix and individual fiber with realtively good success. In these models, the interphase was characterized by some average shear strength, τa, and elastic modulus, Ea. On the other hand, models for tranforming the properties of the micro-scale interphase around individual fiber into the mechanical response of macroscopic multifiber composite have not been generally successfull. The anisotropy of these composite structures are the main reasons causing the failure of these models. The strong thickness dependence of the elastic modulus of the micro-scale interphase suggested the presence of its underlying sub-structure. On the nano-scale, the discrete molecular structure of the polymer has to be considered. The term interphase, originally introduced for continuum matter, has to be re-defined to include the discrete nature of the matter at this length scale. The segmental immobilization resulting in retarded reptation of chains caused by interactions with solid surface seems to be the primary phenomenon which can be used to re-define term interphase on the nano-scale. Thus, the Rubinstein reptation model and a simple percolation model were used to describe immobilization of chains near solid nano-particles and to explain the peculiarities in the viscoleastic response of nano-scale “interphase.” It has also been shown that below 5 nm, Bernoulli–Euler continuum elasticity becomes not valid and higher-order elasticity along with the proposed reptation dynamics approach can provide suitable means for bridging the gap in modeling the transition between the mechanics of continuum matter at the micro-scale and mechanics of discrete matter at the nano-scale.

In 1987, a survey of eye abnormalities was undertaken of the mentally handicapped patients in Stoke Park Hospital, Bristol. The total population was 367 patients (262 females and 105 males). Of the 367 patients reviewed, 218 were found to have one or more eye anomalies (including the Down's Syndrome group), which shows that more than half the patients suffered from eye disorders (59%). The prevalence of the following anomalies is presented in detail: strabismus, refractive errors and cataracts. Corneal anomalies, nystagmus, retinopathy, glaucoma and other eye pathologies associated with various syndromes are noted. Eye anomalies in 31 patients suffering from Down's syndrome in the sample are recorded. Preventative measures to ameliorate the defects of eyesight, particularly in the aging population, relevance of regular eye examination and medical or surgical treatment of eye disorders are discussed.

A case of Marden-Walker syndrome with its typical facies, blepharophimosis, congenital joint contractures, mental handicap and other anomalies is reported in a 29-year-old female and the literature reviewed. There is a history of mental handicap on the paternal side and cancer on the maternal side of the family tree.

This is probably the first retrospective study of an adult mentally handicapped population of incestuous parentage. Eleven known incestuous unions were identified with 38 offspring, of whom 15 were admitted to the Stoke Park group of hospitals. Incest and its legal definition in different societies are considered. The effects of close inbreeding on mortality, morbidity, mental function and adoption are examined. The study also reaffirms that incest is one of the causes of mental handicap in a high percentage of offspring.

A case of a mentally handicapped female with unbalanced form of translocation deletion between chromosomes 6 and 22 is reported. Clinical features, mental disorder and abnormal dermatoglyphs of the propositus are described.

The temperature dependence of critical strain energy release rate (G c ') and standardized Charpy notched impact strength (CNIS) were measured for a thermoplastic polyurethane (TPUR) reinforced with 30 wt% of short glass fibers (SGF) over a temperature interval ranging from -150°C to 23°C (RT) at two strain rates, 70 and 150 s -1 , respectively. Fractographic observation of fracture planes was used to qualitatively assess the fracture modes and mechanisms. Adhesion between the reinforcement and the matrix was excellent and the integrity of the fiber-matrix interfacial contact was relatively insensitive to exposure to hydrolysis during the immersion in boiling water for 100 hours. At temperatures above -30°C, there was a large extent of plastic deformation in the vicinity of crack planes while at temperatures below -50°C, the extent of plastic deformation was substantially reduced. This resulted in a change in the major energy dissipation mechanism and led to a decrease of both CNIS and G c ' values for SGF/TPUR composites. It was suggested that the plastic deformation of TPUR matrix in the immediate vicinity of glass fibers was the primary source of energy dissipation at temperatures above -30°C, while the friction and fiber pull-out was the main dissipative process below -50°C. Over the whole temperature interval investigated, greater G c ' values were obtained at higher strain rate of 150 s -1 , without any significant change in the fractographic patterns observed on the fracture planes. The CNIS/G c ' ratio, used to assess suitability of CNIS for comparison of materials, changed with temperature substantially suggesting that the functional dependences of CNIS and G c ' on temperature differ substantially. Hence, CNIS data do not provide a reliable base for material selection and for design purposes in this case.

In this paper we report on the morphogenesis of dental resins formed by a thermally initiated radical cross-linking copolymerization of model dental resins. These systems were considered reasonable model simplifications of the actual resins used in commercial filling composites, veneers, etc. Effect of bis-GMA content varying from 0 to 100% on the degree of conversion and morphology of the cured resin was investigated. Dynamic scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), dynamic mechanical thermal analysis (DMTA) and high temperature solvent extraction experiments were performed in order to determine the nature and location of unreacted unsaturations in relation to bis-GMA concentration. The interval of cure temperatures, ranging from 23 to 250°C, may seem irrelevant from the clinical point of view but is instrumental for an understanding of the processes involved. Single glass transition temperature (Tg) found in DMTA experiments showed that the copolymerization process between bis-GMA and TEGDMA is random in nature, however, the overall cure reaction is inhomogeneous and this inhomogeneity is increasing with increasing bis-GMA molar fraction. Heterogeneous character of the cure was reflected into the network morphogenesis characterized by microgellation preceded by cyclization and, following connection of microgels. These cure kinetics resulted in a heterogeneous morphology of the cured resin. Moreover, it was shown that the cure kinetics controls to a great extent the degree of conversion of the reactive vinylidene C=C bonds in a fully cured resin. A decrease in bis-GMA concentration in the resin mixture led to a higher degree of conversion, however, even a neat TEGDMA homopolymer did not exhibit C=C conversion greater than 65–70% under the cure conditions used. Leaching out tests, consisting of an extraction of unreacted monomer from a finely ground cured resin in boiling cyclohexanone at 160°C over a period of 5 d, revealed total weight loss of the order of 3.2–5.6 wt % regardless of the total conversion. No uncured monomer was detected in the extract solution using FTIR spectroscopy, however, the method used is not sensitive to the presence of oligomers. It was concluded that the remaining unreacted double bonds are the inevitable result of the diffusion controled heterogeneous cure reaction. The low rate of diffusion in the resin beyond its gel point is controlled by high monomer rigidity, low mobility and radius of gyration of the monomers. The unreacted C=C bonds exist in the form of pendant, side groups chemically attached to the network. In addition, a hypothesis has been proposed that for concentrations of rigid bis-GMA monomers above 50 wt %, preferably only one methacrylate group of its molecule has reacted on the time span of the experiment performed and has been incorporated in the cured network. Hence, a substantial part of unsaturation exists in the solid polymer in the form of pendant groups formed by mechanically ineffective bis-GMA monomers. The results are in good qualitative agreement with computer simulations based on the kinetic gelation model. © 2000 Kluwer Academic Publishers

Sixty-four mentally retarded people with hemiplegia (35 females and 29 males), first recorded in 1963, were re-examined 30 years later for life expectancy. Detailed physical and mental states, lengths of hospital stays and other information were noted. Recent advances in diagnosis and prognosis of hemiplegics were included. The results of the study indicate that, with special provisions available, people with hemiplegia have the prospect of reaching pensionable age and beyond: the oldest female is 85 and the oldest male 76 years of age.

Dependencies of the yield strength (σyc), yield strain (ɛyc) and Charpy notched impact strength (CNIS) of polypropylene (PP) reinforced with 30 wt% short glass fibres (SGF) and ethylene — propylene random copolymer (EPR) inclusions on EPR volume fraction (ve) were investigated within the interval of ve varying from 0–0.2. Only one limiting phase morphology has been attained reproducibly using a procedure based on chemical modification of PP. Adhesion enhancement between SGF and PP and complete separation between SGF and EPR was achieved by grafting PP with 2wt % maleic anhydride (MAH). Two regions existed on σyc versus ve curves in the case of complete separation of the reinforcement and elastomer. The observed increase of σyc with increasing ve within the interval 0

Elastic and viscoelastic moduli, yielding and failure of ternary composites of thermoplastic matrix filled with particulate fillers and elastomer inclusions are discussed. Modeling of the role of elastomer interphase in elastic response and in failure processes, based on the combination of numerical method (Finite Element Analysis) and percolation concept, is presented for PP/EPR/filler systems. Proposed expressions for Young modulus, yield strength and critical strain energy release rate are used to predict the lower and upper limiting values of these properties in the case of the two limiting morphologies. Good agreement is found between theoretical predictions and experimental data.

The effects of oxyen plasma treatment on the surface chemistry of Spectra 1000® high modulus polyethylene fibers and on the mechanical properties of fiber-reinforced composites of the fibers in a Bis-GMA based acrylic resin have been studied. X-ray photoelectron spectroscopy and diffuse reflectance FTIR spectroscopy have been used to show that the majority of oxygen on the fiber surface exists mostly in the form of ether and/or epoxy linkages, with carbonyl-, carboxylic- and ester-containing compounds accounting for less than 10 percent of the total. While the untreated and plasma-treated fibers have similar chemical compositions, the surfaces of the plasma-treated fibers are more polar and the oxygen is chemically bonded instead of being merely physisorbed. The interfacial shear strength between the fibers and the acrylic resin is increased by a factor of 2.3 by the plasma treatment indicating the presence of a weak boundary layer on the surface of the untreated fibers. The hydrolytic stability ...

The effects of phase morphology, interfacial adhesion and filler particle shape and volume fraction on the fracture toughness of polypropylene (PP) filled with CaCO3 or Mg(OH)2 and ethylene-propylene elastomer (EPR) were investigated. Separation of the inorganic filler and elastomer particles was achieved using maleic-anhydride-grafted PP (MPP) to enhance the inorganic filler-matrix adhesion. Encapsulation of the rigid filler by the elastomer was achieved by using maleic-anhydride-grafted EPR (MEPR) to increase the inorganic filler-elastomer adhesion. The two limiting morphologies differed significantly in fracture toughness under impact loading at the same material composition. A model for a mixed mode of failure, accounting for the plane strain and plane stress contributions to the strain energy release rate,G c, was used to predict the upper and lower limits forG c for the two limiting morphologies over an interval of elastomer volume fractions,v e, from 0–0.2 at a constant filler volume fraction,V f = 0.3, and over the filler volume fraction from 0–0.4 at constant EPR content. The role of material yield strength in controlling fracture toughness has been described successfully using Irwin's analysis of plastic zone size. The presence of elastomer enhances both the critical strain energy release rate for crack initiation,G c, and the resistance to crack propagation as expressed by Charpy notched impact strength for the two limiting morphologies. Satisfactory agreement was found between the experimental data and predictions of upper and lowerG c limits.

The effects of phase morphology, interfacial adhesion, rigid filler particle shape and elastomer volume fraction on the tensile yield strength of polypropylene (PP) filled with inorganic filler (CaCO3 or Mg(OH)2) and ethylene-propylene elastomer (EPR) were investigated. Separation of the filler and elastomer particles was achieved using maleic-anhydride-grafted PP (MPP) to enhance the filler-matrix adhesion. Encapsulation of the rigid filler by the elastomer was achieved using maleic-anhydride-grafted EPR (MEPR) to increase the filler-elastomer adhesion. The two limiting morphologies differ significantly in mechanical properties under tensile loading at the same material composition. Elastomer particles separately dispersed in the matrix enhance the shear banding in the bulk matrix which prevents the crazes growing from the filler surface from becoming unstable and, thus, increases the ductility of the material. Encapsulation by an elastomer layer on the filler surface relieves triaxial stresses at the filler surface, changing the major local failure mechanism from crazing to shear yielding and, hence, increasing the ductility of the material. Increase of the elastomer volume fraction also causes, in both cases, an increase in matrix ductility. Composite models are used to predict upper and lower limits of yield strength (σy) for the two limiting morphologies over an interval of elastomer volume fractions (V e) from 0 to 0.2 at a constant filler loading of 30 vol.% and over a filler volume fraction from 0 to 0.4 at a constant EPR content in the matrix. Satisfactory agreement was found between the experimental data and theoretical predictions.

Experimental data on the standard Charpy notched impact strength (CNIS) for a large sampling of particulate-filled and rubber-modified polypropylenes were ana lyzed. To determine the significance of the CNIS for material selection and design, CNIS data were compared with fracture toughness measurements expressed as the critical strain energy release rate G' c , measured under impact loading. A scale factor representing the state of stress at the crack tip was calculated, assuming small scale yielding, Class I linear elastic fracture mechanics (LEFM). Based on the data. three principal groups of materials were identified. In the smallest of the three. CNIS and G' c measurements showed the same functional dependence on the maternal variables studied and were characterized by a scale factor independent of the composition. In these cases, one can justify comparisons of toughness of different compositions using single values of the CNIS, since the materials are probably being compared in equivalent states of stress. In a second group, CNIS and G' c also show the same functional dependence on maternal variables, but exhibit large variations in the scale factor with composition. One should not compare the toughness of different materials from this group based on single values of CNIS, since it is likely that the comparisons would not be made relative to equivalent states of stress. In these cases, only measurements of G' c can separate the effect of specimen geometry from those of the intrinsic properties of the material. The majority of materials studied fell into a third group, in which the CNIS and G' c exhibited substantially different functional dependencies on the material properties, and the scale factors depended also on composition. In these latter cases, a comparison of CNIS values for different compositions is not a reliable indication of the relative toughness and is of little value as a parameter for material selection and design

The effect of elastomer volume fraction and phase morphology on the elastic modulus of ternary composites polypropylene (PP)/ethylene-propylene rubber (EPR)/inorganic filler containing 30 vol % of either spherical or lamellar filler has been investigated. Phase morphology was controlled using maleated polypropylene (MPP) and/or maleated ethylene-propylene elastomer (MEPR). As revealed by SEM observations, composites of MPP/EPR/filler exhibit separation of the filler and elastomer and good adhesion between MPP and the filler, whereas composites of PP/MEPR/filler exhibit encapsulation of the filler by MEPR. Composite models were utilized to estimate upper and lower bounds for the elastic modulus of these materials, which is strongly dependent on the morphology of the ternary composite. A model based on the Kerner equation for perfect separation of the soft inclusions and rigid fillers gives a good prediction of the upper limit for relative elastic modulus as a function of filler and elastomer volume fractions. The lower limit, achieved in the case of perfect encapsulation, depends significantly on the particle shape. Good agreement was found between experimental data and lower limits predicted using the Halpin-Tsai equation for lamellar filler and the Kerner-Nielsen equation for spherical filler. In order to calculate reinforcing efficiency of the core-shell inclusions, the finite element method (ANSYS 4.4A, GT STRUDL) has been used.

The mechanical properties of an orthodontic wire pultruded from S2-glass-reinforced polyethyleneterephthalate glycol (PETG) were measured using two experimental devices simulating clinical conditions. A comparison of moduli measured in the clinically relevant devices with those measured in a standard flexural test reveals that data obtained using small cross-section, short span length clinical specimens require corrections associated with clamping and shearing effects. The clamping effect dominates and is caused by the softening of the material near the clamps. The shear effect becomes important at high fibre volume fractions and small span/thickness ratios. With adoption of these corrections, good agreement between moduli calculated using rule of mixtures and those measured in clinical tests is achieved. The analytical base developed for prediction of the stiffness of the orthodontic wire for different span/thickness ratios improves the procedure for design of dental appliances.

Clinical implementation of fibre-reinforced composites (FRCs) for treatment of misaligned teeth requires a stability of the material under stress in a moist environment. The performance of the material is strongly dependent on its resistance to hydrolytic deterioration of the components. Of particular concern are the quality and durability of the interfaces between the fibres and the matrix. Scanning electron microscopy (SEM) was utilized to evaluate qualitatively the effect of water immersion on the interfaces between constituents in a variety of E-glass fibre-reinforced thermoplastics. A particular series of organosilane-coated fibres embedded in polycarbonate (PC) were chosen for further quantitative study of the residual shear strength of the interfaces using an embedded-single-fibre test. Annealed PC and maleated polypropylene (MPP) reinforced with bare E-glass fibres have an appropriate combination of mechanical properties and environmental stability for potential orthodontic applications. The usual sizing agents used for commercial E-glass fibres interfere with the bonding of the fibres to the matrix and the usual silane treatments used to promote bonding could lead to problems of hydrolytic stability under extreme conditions of stress and moisture.

The effect of a deterioration of matrix and matrix-fibre interface, caused by moisture, on the flexural properties (modulus, strength and ultimate strain) of unidirectional E-glass fibre-reinforced thermoplastics [polycarbonate, poly(ethyleneterephthalate glycol) and nylon 12] was investigated. Specimens of span/thickness ratio varying from 15 to 30, prepared from pultruded thermoplastic prepregs, were tested in directions parallel to and perpendicular to the fibre orientation as moulded and after immersion in water at 85°C for 100 h. No significant reduction in longitudinal properties, controlled by fibre behaviour, resulted from exposure to water. A significant reduction in transverse properties, controlled by the matrix and interface behaviour, was observed. Polycarbonate/bare E-glass fibre composite annealed at 275°C for 1 h before immersion in water exhibited a superior resistance to moisture attack. This phenomenon is attributed to the “transcrystalline” interphase near the fibre surface and good wetting of fibres by the matrix. Resistance against moisture favours this material for further clinical application as an orthodontic wire.

The effect of adhesion on the strain energy release rate (Gc) and Charpy notched impact strength (NIS) of calcium carbonate (CaCO3)-filled polypropylene (PP) at room temperature is investigated over a wide interval of particulate filler volume fractions. The concentration dependence of Gc and NIS are discussed in terms of competition between the effects of increasing stiffness, decreasing effective matrix cross section, and the transition from a plane strain to a plane stress mode of failure. In all cases the plane stress and plane strain limits of the critical strain energy release rate for initiation of cracks were not affected by the presence of the filler and are the same as those for neat matrix. In the case of no adhesion between components, the size of the crack tip plastic zone increases with increasing filler volume fraction (vf) because of the reduction of the material yield strength. In the region 0 < vf < 0.12, there is a mixed mode of failure, and the measured value of Gc for crack initiation increases steadily as the sample cross section approaches a fully plane stress state. The reduction in yield strength also results in the increase in Gc for crack propagation as reflected by an increase in NIS. Above vf= 0.12, the specimen cross section is in a fully plane stress state, and further increase in filler volume fraction (decrease in matrix effective cross section) has the net effect of reducing both Gc and NIS. In the case of “perfect” adhesion, the yield strength increases only slightly with vf. In the region 0 < yr < 0.05 there is also a mixed mode of failure, but the increase in Gc is much less than that for the no-adhesion case since the size of the plastic zone in front of the crack is much smaller. Above vf= 0.05, the combined effects of increasing stiffness, reduction of the size of the plastic zone, and decreasing matrix cross section dominate the behavior, causing a steady reduction in both Gc and NIS. Good agreement was found between experimental data and calculations based on fracture mechanics principles.

Dynamic mechanical, tensile and impact properties and modes of failure of binary blends of polypropylene and ethylene-propylene random copolymer rubber (PP/EPR) were studied over a wide interval of EPR volume fractions. The effect of grafting maleic anhydride on both PP and EPR on the mechanical properties was also investigated. The effects of elastomer inclusions on the failure processes were analysed in terms of critical strain energy release rate and Charpy notched impact strength (NIS). Phase morphology of the blends was examined using dynamic mechanical spectroscopy and SEM. PP remains as a continuous phase even as a minor component. This is reflected by the experimental values of elastic moduli significantly higher than those predicted using the Kerner model. The plane strain and plane stress limits of the critical strain energy release rate for initiation of cracks in the blends were the same as those for neat PP. On the other hand, the presence of EPR decreased the yield strength of the material due to the overlapping stress fields of adjacent particles, thereby increasing significantly the critical strain energy release rate for crack propagation. This was reflected by an increase in NIS. The results are explained in terms of a mixed mode of fracture with macroscopic transition from the state of plane strain to plane stress.

The effects of the filler volume fraction and strength of adhesion on the mode of tensile failure of a particulate reinforced polypropylene (PP) are investigated using finite element simulation (FES). When there is perfect adhesion between con- stituents, an upper bound for tensile yield strength is found to be 1.33 times the matrix yield strength above a critical volume of particulate concentration. Utilizing Sjoerdsma's model for interacting stress concentration fields, one can determine the concentration dependence of the yield strength below the critical filler volume fraction

Persistent subcutaneous nodules may arise after vaccination or allergen desensitization. The swelling might appear as a result of a specific histiocytic reaction to aluminum, which is used in many preparations to hasten immune response. A wide range of such vaccines are used in national childhood vaccination programs. Such nodules are frequently itchy or painful with local skin alterations. The condition tends to resolve spontaneously, although long-term observation is recommended. We describe the clinical history of a 10-year-old girl who presented with an itchy subcutaneous nodule that appeared five months after her second DiTe revaccination.

In polymer matrix composites, exhibiting heterogeneous structure at multiple length scales, the interphase phenomena at various length scales were shown to be of pivotal importance for the control of the performance and reliability of such structures. At the micro-scale, the interphase is modelled as a 3D continuum with some average properties most commonly resulting from data fitting procedures. Number of continuum mechanics models was derived over the last 50 years to describe the stress transfer between matrix and an individual fiber, considering the interphase with various chemical structure and thickness the third component of the model composite characterized by some average shear strength, τa, with realtively good success. The observed strong thickness dependence of the elastic modulus of the interphase with thickness smaller than 500 nm suggested presence of its underlying nano-scale molecular sub-structure. On the nano-scale, the discrete molecular structure of the polymer has to be considered. At this length scale, the continuum mechanics can only be used for materials with characteristic length scale greater than approximately 20 nm. Below 20 nm, continuum mechanics becomes not valid and gradient-strain elasticity along with molecular dynamics approach has to be used. The segmental immobilization seems to be the primary mechanism controlling the behavior of nano—scale “interphase”. Modified reptation model was used to describe the dynamics of chains near a solid nano-particles and to explain the peculiarities in the viscoleastic response of polymer nanocomposites. These results reflecting the discrete molecular nature of the nano-scale interphase can be used in gradient-strain elasticity models. Experimental results obtained for model nanocomposites were used to support theoretical predictions.

To give the Slovenian communes and their inhabitants the possibility to obtain information about electromagnetic fields in their neighborhood, Forum EMS – an independent project aimed to inform general public about electromagnetic fields and their biological effects – started monitoring campaign in 2005. In communes expressed the interest, remote monitoring station was installed for one week. The value of electric field intensity was stored every minute 24 hours a day and. For each location all collected data were evaluated and presented to the interested public as an article in commune bulletin and on internet, where the data for all locations are available. In last two years more than 35 communes participated in this campaign. The monitoring campaign showed that typical electromagnetic field exposure due to GSM base stations in urban area is low. Maximum values reach 2 % of reference level for I. region of Slovenian legislation, which is 0.2 % of ICNIRP reference level for general public. Due to the vicinity of radio and TV broadcasting tower in one case, instead of GSM probe, wide band probe was used. In this case, measured electric field was 40 % of reference level for I. region of Slovenian legislation (4 % of ICNIRP reference level for general public).

In this paper we report on the morphogenesis of dental resins formed by a thermally initiated radical cross-linking copolymerization of model dental resins. These systems were considered reasonable model simplifications of the actual resins used in commercial filling composites, veneers, etc. Effect of bis-GMA content varying from 0 to 100% on the degree of conversion and morphology of the cured resin was investigated. Dynamic scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), dynamic mechanical thermal analysis (DMTA) and high temperature solvent extraction experiments were performed in order to determine the nature and location of unreacted unsaturations in relation to bis-GMA concentration. The interval of cure temperatures, ranging from 23 to 250 degrees C, may seem irrelevant from the clinical point of view but is instrumental for an understanding of the processes involved. Single glass transition temperature (Tg) found in DMTA experiments showed that the copolymerization process between bis-GMA and TEGDMA is random in nature, however, the overall cure reaction is inhomogeneous and this inhomogeneity is increasing with increasing bis-GMA molar fraction. Heterogeneous character of the cure was reflected into the network morphogenesis characterized by microgellation preceded by cyclization and, following connection of microgels. These cure kinetics resulted in a heterogeneous morphology of the cured resin. Moreover, it was shown that the cure kinetics controls to a great extent the degree of conversion of the reactive vinylidene C=C bonds in a fully cured resin. A decrease in bis-GMA concentration in the resin mixture led to a higher degree of conversion, however, even a neat TEGDMA homopolymer did not exhibit C=C conversion greater than 65-70% under the cure conditions used. Leaching out tests, consisting of an extraction of unreacted monomer from a finely ground cured resin in boiling cyclohexanone at 160 degrees C over a period of 5 d, revealed total weight loss of the order of 3.2-5.6 wt % regardless of the total conversion. No uncured monomer was detected in the extract solution using FTIR spectroscopy, however, the method used is not sensitive to the presence of oligomers. It was concluded that the remaining unreacted double bonds are the inevitable result of the diffusion controlled heterogeneous cure reaction. The low rate of diffusion in the resin beyond its gel point is controlled by high monomer rigidity, low mobility and radius of gyration of the monomers. The unreacted C=C bonds exist in the form of pendant, side groups chemically attached to the network. In addition, a hypothesis has been proposed that for concentrations of rigid bis-GMA monomers above 50 wt %, preferably only one methacrylate group of its molecule has reacted on the time span of the experiment performed and has been incorporated in the cured network. Hence, a substantial part of unsaturation exists in the solid polymer in the form of pendant groups formed by mechanically ineffective bis-GMA monomers. The results are in good qualitative agreement with computer simulations based on the kinetic gelation model.

Two cases of dysthymia in mentally handicapped patients are described. The absence of publications on dysthymia in the mentally handicapped is noted. The importance of early diagnosis and treatment with advanced antidepressants and psychotherapy is emphasised.

The present paper describes age-related fractures in 68 people with intellectual disability and epilepsy (39 females and 29 males). A higher incidence of fractures in epileptic subjects (26%) was noted when they were compared with non-epileptic patients (15%). In the sample of 263 epileptics (121 females and 142 males), a higher number of females (32%) sustained fractures than their male counterparts (20%). The peak period of all fractures is between 40 and 49 years of age. The highest incidence of fractures in females occurred during the periods from 10 to 19 and 40 to 49 years, while the peak was between 30 and 39 years for males. The causes of fractures and preventative measures are discussed, and further avenues for research are indicated.

The records of 17 people with intellectual disability and untreated phenylketonuria (12 females and five males), who were resident in the Stoke Park Group of Hospitals, Bristol, England, 25 years ago, were re-examined for life expectancy. Six subjects had died (five females and one male). The oldest deceased female was 69 years of age. The average age at death was 55.8 years. Eleven subjects were still alive (seven females and four males). The oldest living male was 79 years of age. The average age of the survivors was 55.7 years.

In a retrospective study of hospital records over a 50-year period, data on 32 patients who died as a result of intestinal obstruction are presented and compared with comparison groups and national mortality statistics. There was a higher incidence and lower mean age at death of fatal intestinal obstruction compared with the total national population. The mean age at death significantly increased over the study period. Intestinal volvulus was a common cause of obstruction particularly in those with cerebral palsy. There was a high prevalence of chronic constipation and megacolon. Foreign-body obstruction was de facto related to pica, but overall, there was a low prevalence of pica. Overall, mean IQ was low, but only significantly so in the male subjects. The length of acute illness was short; in 22 patients it was less than 24 h. Vomiting and abdominal distension were often absent and abdominal signs were recorded only in five patients. Pain or distress was recorded in only nine patients. Only eight patients were correctly diagnosed before death and only two had surgery. The results suggest that fatal intestinal obstruction is more common in mentally handicapped people and chronic constipation and megacolon are risk factors. Intestinal obstruction in mentally handicapped people can present late and with deceptively minimal signs and symptoms.

In four hospitals for the mentally handicapped, 302 patients died during the decade 1976–85; of these, 53 (17.5%) died from cancer. The percentage of deaths from all types of cancer during that period showed an increase, particularly in gastrointestinal cancer, as compared with the previous four decades.