Coating of a lignocellulosic aggregate with pectin/polyethylenimin mixtures: Effects on flax shive and cement-shive composite properties

Lignocellulosic lightweight concretes are a potential contributor to sustainable development. However, lignocellulosic aggregates are not always fully compatible with cement matrices leading to setting delays, significant dimensional variations and low mechanical strengths. An aggregate treatment, reducing water absorption and water-soluble molecule release, can avoid or reduce these drawbacks. In this study a coating treatment, using a pectin/polyethylenimin (PP) mixture, was applied to flax shives, which is a lignocellulosic by-product. Before shive coating, a dilution with distilled water or a micro-wave heating were conducted to decrease PP mixture viscosity.The PP treatment involved a decrease in shive water absorption. Compared to standard shive concrete, treated shive concrete exhibited a decrease in setting delay with an increase in cement hydration enthalpy, an increase in mechanical strengths and a significant reduction in dimensional variations. Although a slight increase in thermal conductivity and bulk density was measured, the cement-shive composite obtained still belongs to the insulating concrete category.     

Tissue reactions of subcutaneously implanted mixture of ε-caprolactone-lactide copolymer and tricalcium phosphate. An electron microscopic evaluation in sheep

Biodegradable polymers, mainly derivates of -hydroxy acids, are widely used today in oral- and maxillofacial surgery, orthopedics, and other fields of surgery. These biomaterials are well tolerated by living tissue and fracture fixation devices made of polylactic or polyglycolic acid are clinically widely used today. Still, there are some problems in application of biodegradable polymers. Abacterial inflammatory reactions have been noticed after the clinical introduction of these devices. Both swelling and pain at the site of implantation have also been reported. The etiology of this inflammatory reaction is still unknown, despite the numerous studies. Therefore, the aim of the present study was to further characterize this inflammatory reaction in detail, by electronmicroscopy. We prepared a mixture of -caprolactone–lactide copolymer and tricalcium phosphate and placed it in the dermis in 12 sheep. Follow-up times were 9, 14, 24, and 52 weeks. We found that the mixture caused a mild inflammatory reaction. There were no signs of cell damage. Fibroblasts, macrophages, and eosinophils were found adjacent to the copolymer. The mixture is easy to handle and can be moulded into different shapes in room temperature. The results encourage us to continue our studies to develop a filling material for bone defects.     

Electropolymerization of N-methylanthranilic acid and spectroelectrochemical characterization of the formed film

The electropolymerization of N-methylanthranilic acid (NMAA) is reported in this paper. The monomer is substituted both at ortho- and N-position and, to the best of our knowledge, it has not been previously electropolymerized. Electropolymerization of NMAA was done on glassy carbon and optically transparent (indium) tin oxide electrodes. The obtained films, which are probably of an oligomeric nature (oligoNMMA), were characterized with cyclic voltammetry (CV), in situ UV–vis and Raman spectroscopy, ex situ FTIR spectroscopy and scanning electron microscopy (SEM).Our results show that NMAA can be electropolymerized as thin films in 1.0 M HClO₄, but the oxidation and reduction peak currents in the CVs indicate that the formed oligoNMAA films are thinner than poly(N-methylaniline) or poly(N-butylaniline) films prepared under similar conditions. The CV and UV–vis measurements confirm that oligoNMAA have three oxidation states like suggested in the redox scheme of substituted polyanilines. The Raman spectra of oligoNMAA also verify that more quinoid units are formed at higher potentials in accordance with the redox scheme. The ex situ FTIR measurement proves that covalently attached carboxylic acid groups are present in the film structure and attached to the oligoNMAA backbone.     

Silicate Release from Sand-Manipulated Sediment Cores: Biogenic or Adsorbed Si?

The influence of an addition of either sand and/or spring-bloom algae on the efflux of nutrients from intact sediment cores from the Baltic Sea was studied in a flow-through experiment. The addition of sand significantly increased the efflux of silicon (Si) from sediment, but the algal addition did not. The effects on phosphorus (P) were not as clear, and fluxes of nitrogen (NH₄ and NO_2?+?3) remained relatively unaffected by the additions. The small effect of the algal addition was caused by the short time-period covered by the experiment and possibly by adsorption of released Si by the sediment. A follow-up bottle experiment showed that despite the apparently lower content of easily available Si and biogenic silica, BSi, in the sand, the sand-induced Si efflux was caused by release of Si from the sand itself, rather than by indirectly increasing the dissolution of BSi present in the sediment.     

Influence of charged tail groups of self-assembled monolayers on electrodeposition of polyaniline

Self-assembled monolayers (SAMs) of thiols with three different tail groups, −COOH, −SO₃Na, and −NH₂, were used to modify the Au substrates for electrodepositing polyaniline (PANI). Electrochemical quartz crystal microbalance (EQCM) results indicated a slower rate of deposition of PANI on a SAM surface consisting of positively charged amine groups compared to polymerization on bare gold and on a SAM of carboxyl acid groups. The properties of the SAM layers are dependent on the pH value of the solutions, and are effective only at very low pH values (pH < 2). A layer of the positively charged amino groups in acidic solution acted as a barrier for electron transfer in electro-oxidation of aniline monomer. The positively charged SAM of amine groups also increased repulsion between the coupled aniline species and the electrode surface and in this way hindered electrodeposition. Modification of the surface with pre-patterned SAMs have been demonstrated to be a convenient and practical way to fabricate selectively deposited thin films of polyaniline.     

Ion-implanted capacitively coupled silicon strip detectors with integrated polysilicon bias resistors processed on a 100 mm wafer

Double-sided silicon strip detectors with integrated coupling capacitors and polysilicon resistors have been processed on a 100 mm wafer. A detector with an active area of 19 × 19 mm² was connected to LSI readout electronics and tested. The strip pitch of the detector is 25 μm on the p-side and 50 μm on the n-side. The readout pitch is 50 μm on both sides. The number of readout strips is 774 and the total number of strips is 1161. On the p-side a signal-to-noise of 35 has been measured using a ⁹⁰Sr β-source. The n-side has been studied using a laser.     

Epidermal growth factor, transforming growth factor-alpha, and epidermal growth factor receptor in labial salivary glands in Sj?gren's syndrome

OBJECTIVE: Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) affect cells through binding to a shared EGF receptor (EGF-R), which is a transmembrane protein with tyrosine kinase activity. They exert trophic effects on vascular endothelial, salivary acinar, and ductal and mucosal epithelial cells. In Sj?gren's syndrome (SS) focal sialadenitis leads to salivary gland tissue damage, diminished salivary flow, and changes in the oral epithelium, a complex referred to as xerostomia. We compared the localization of EGF, TGF-alpha, and EGF-R in labial salivary glands in SS and in healthy controls. METHODS: Labial salivary gland tissues of 12 patients with SS and 7 healthy controls were stained with the immunohistochemical peroxidase-antiperoxidase method for EGF, TGF-alpha, and EGF-R. RESULTS: Immunoreactivity for both EGF and TGF-alpha was found in endothelial cells of blood vessels and in some ductal epithelial cells. TGF-alpha, but not EGF, was also found in some acinar cells. EGF-R was found in endothelial, acinar, and salivary duct epithelial cells. There was no difference in the expression of EGF-R between diseased and healthy specimens, but both EGF and TGF-alpha were diminished in SS. CONCLUSION: The interrelated localization of EGF-R and its ligands, EGF and TGF-alpha, suggests an autocrine, juxtacrine, and paracrine mitogenic/trophic role for them and thus a role in the maintenance of the secretory and excretory cells of the normal salivary glands. The trophic effects on acinar cells seem not to be mediated by EGF, but more likely by TGF-alpha. The diminished expression of EGF and TGF-alpha indicates a failure of this trophic system in SS, which may contribute to the acinar atrophy and secondary changes thereof, including atrophy of the oral mucosa.     

Quantitative assessment of mast cells in recurrent aphthous ulcers (RAU)

Previous studies on the frequency of mast cells (MCs) in recurrent aphthous ulcers (RAU) have yielded conflicting results. Monoclonal antibodies specific for tryptase (AA1) and anti-IgE (polyclonal antibody) were used to identify density and distribution of MCs in an immunohistochemical study of RAU (n=15), induced oral traumatic ulcers (TUs) (n=9), and control clinically healthy oral mucosa (n=15). Results were quantified by means of a VIDAS image analyzer. In all sections studied, IgE-positive cells showed similar frequency and distribution to tryptase-positive MCs. In RAU lesions, numerous tryptase-positive MCs were found in the sub-epithelial lamina propria, but MC numbers in the epithelium were low and present only in some RAU biopsies. MCs were also more numerous in RAU-inflammatory infiltrates (118+/-31 cells/mm2) than those seen in TU-inflammatory infiltrates (75+/-18 cells/mm2, P<0.001). MC activation/degranulation, as judged by diffuse extracellular tryptase staining, was a common feature within RAU-inflammatory infiltrates and at RAU-inflammatory infiltrates-connective tissue interfaces, which were often associated with connective tissue disruption. MC counts in the RAU connective tissue, lateral to the inflammatory infiltrates, were significantly greater than in the connective tissue of TUs and of control biopsies (124+/-36 vs 73+/-13 vs 69+/-21 cells/mm2, respectively; P<0.001). Overall, MCs were significantly increased in aphthae (116+/-26 cells/mm2) compared with TU lesions (72+/-11 cells/mm2, P<0.001) and controls (71+/-16 cells/mm2, P<0.001). In conclusion, MC numbers are increased in a typical topographical pattern, and the local MCs show signs of activation/degranulation suggesting active involvement of this cell type in RAU pathogenesis.     

Dietary fats and properties of endoplasmic reticulum: II. Dietary lipid induced changes in activities of drug metabolizing enzymes in liver and duodenum of rat

Rats were fed cholesterol, cacao butter, or olive oil diets to determine the effect of dietary lipids on the rate of drug biotransformation in the liver and duodenum. The cholesterol rich diet maintained the hepatic aryl hydrocarbon hydroxylase activity at the same level as did the standard diet. Rats fed olive oil and cacao butter diets showed lower hepatic aryl hydrocarbon hydrorylase activity. The p-nitroanisole 0-demethylase activity was doubled in hepatic microsomes of rats fed the high cholesterol diet when compared to rats fed the standard diet. The hepatic uridine diphosphate glucoronosyltransferase activity showed different patterns depending on the in vitro treatment of the microsomal membranes. If the enzyme activity was assayed from the native, untreated microsomes, an increase in the measurable uridine diphosphate glucuronosyl transferase activity was found in rats having cholesterol rich diet. After the in vitro activation of membrane-bound uridine diphosphate glucuronosyltransferase by trypsin, the increase in measurable activity was 10 fold in the group fed the standard diet, 6 fold in group fed cholesterol, 4 fold in group fed cacao butter, and 3 fold in group fed olive oil. Trypsin digestion of microsomes increased the measurable uridine diphosphate glucuronosyltransferase activity less in rats fed diets rich in neutral fats than those fed the standard diet. In the duodenal mucosa, lipid diets decreased the activities of drug hydroxylation and glucuronidation.     

Activation of periprosthetic connective tissue in aseptic loosening of total hip replacements

In aseptic loosening of initially well inserted total hip prostheses, implant wear debris and cyclic mechanical loading lead to a foreign body type of chronic inflammatory reaction, then to osteolysis, and finally to loosening of the implant. In the present work the reactive and adaptive changes of the periprosthetic tissues and pseudojoint were characterized by analysis of the local cell proliferation. Immunohistochemical demonstration of proliferating cells was performed by application of affinity purified rabbit antihuman Ki-67 antibodies to periprosthetic tissues obtained from revision operations for loose total hip prostheses. The fibrous areas and, in particular, the cell rich, vascular areas of the interface tissue (between implant and bone) and the pseudocapsule around aseptically loosened implants contained higher numbers of proliferating cells than the tissues around well fixed implants. In addition, the pseudosynovial lining occasionally contained some Ki-67 positive proliferating cells. Somewhat surprisingly, proliferating vascular endothelial cells were relatively rare. These findings suggest that reactive (interface tissues) and adaptive (pseudojoint and capsule formed around the artificial joint) tissue changes in loosening total hip prostheses comprise proliferation of local fibroblastlike cells. It is concluded that periprosthetic tissues of the loosened total hip prosthesis represent activated mesenchymal tissue.