Heterogeneous mutations in the gene encoding the alpha-subunit of the stimulatory G protein of adenylyl cyclase in Albright hereditary osteodystrophy

Albright hereditary osteodystrophy (AHO) is an inherited disorder associated with deficient activity of the alpha-subunit of the guanine nucleotide-binding regulatory protein (Gs alpha) that couples receptors to adenylyl cyclase. To identify mutations that lead to Gs alpha deficiency, we isolated genomic DNA from patients with AHO and used the polymerase chain reaction to amplify exons of the Gs alpha genes. DNA was amplified using intron-specific oligonucleotide primers flanking exons of the Gs alpha gene. To optimize our ability to detect mutations, one oligonucleotide from each primer pair was synthesized with a 5' GC-clamp. Amplified Gs alpha gene fragments were analyzed by denaturing gradient gel electrophoresis in order to detect mutations that alter the melting point of the double-stranded DNA fragment. Using this technique, we have identified and characterized three mutations and one neutral polymorphism. The polymorphism, located in exon 5, consisted of a T-->C substitution that conserves the isoleucine residue at codon 131 (ATT-->ATC). Two mutations were missense mutations, which in one family consisted of a nucleotide substitution (T-->C) in exon 4 that results in replacement of Leu by Pro at codon 99 of the Gs alpha molecule. Affected subjects in a second family had a single base (C-->T) mutation in exon 6 that resulted in replacement of Arg by Cys at codon 165. A 4-base pair deletion (GTGG) in exon 8 at position +214 was identified in one Gs alpha allele from each affected subject in the third family. This mutation causes a frameshift after the codon for Gln213 that results in a premature stop codon 81 base pair after the deletion. Immunoblot analysis of plasma membranes prepared from cultured fibroblasts or erythrocytes indicated that levels of immunoactive Gs alpha protein were decreased in all affected subjects. We conclude that heterogeneous mutations in the gene encoding Gs alpha, including deletions and single amino acid substitutions, are responsible for Gs alpha deficiency in AHO.     

A generalized theory of simple thermomechanical materials

We develop here a constitutive theory for the generalized simple thermomechanical materials by resorting to generalized thermodynamics in which the empirical temperature is replaced by the thermodynamic temperature which is itself a constitutive function. The restrictions imposed by the generalized Clausius-Duhem inequality on the constitutive relations are fully explored and the theory is applied to a special thermoviscoelastic material.     

Factors influencing the activity and thermostability of immobilized porcine pancreatic lipase

Lipase from porcine pancreas was immobilized on cellulose beads having various degrees of hydrophobicity, by covalent linking and by hydrophobic adsorption. Lipolytic activity was measured in heterogeneous organicaqueous systems of various hydrophobicities using olive oil as a substrate. The main factors influencing lipase activity were hydrophobicity of the reaction mixture and of the carrier. Carriers with increased hydrophobicity enhanced lipase activity more than less hydrophobic ones. Lipase immobilized covalently on cellulose beads was less active than that adsorbed onto tritylcellulose but was considerably more thermostable.     

Treatment of Water Contaminated with Chlorinated Organic Herbicide 2,4-D by an Ozone/Gamma Process

Radiation-induced degradation of 50 ppm 2,4-dichlorophenoxyacetic acid (2,4-D) was investigated in different ozonation times. Co-60 gamma-source was used as a gamma-source with a dose rate of 0.07 kGy/h. Ozonized samples were irradiated for the 0.2 kGy dose. It is observed that irradiation enhances the degradation of 2,4-D with ozone. The amount of passed ozone from samples is between 0.0695 g/L and 8.33 g/L with a flow rate of ozone at 0.078 L/min (10 g/h), from 10 s to 1200 s with the ozone generator. Aliphatic acids and chloride were determined with ion chromatography. Formaldehyde, dissolved oxygen, pH and total acidity were also measured. Both species and amounts of radiolytic intermediates were determined. 2,4-dichloro phenol (2,4-DCP) is one of the toxic intermediates of 2,4-D observed with GC/MS and it decomposes at further ozonation times. It is observed that combination of ozone/gamma irradiation is more effective for degradation of 2,4-D and its intermediate 2,4-DCP. Chloride ions are observed as completely released with combined processes at lower ozonation times although nearly 98% are released with 20 min' ozonation. Intermediate 2,4-DCP decomposes at earlier ozonation times than 2,4-D.     

Enzymatic production of human milk fat analogues containing stearidonic acid and optimization of reactions by response surface methodology

Human milk fat analogues containing stearidonic acid (SDA) were produced by enzymatic acidolysis reactions between tripalmitin and free fatty acids (FFA) obtained from hazelnut oil and commercial oil mixture containing Echium oil. Lipozyme^® TL IM, immobilized sn-1,3 specific lipase was used in the enzymatic reactions. Response surface methodology (RSM) was applied by using central composite circumscribed design with five levels and three factors. The factors chosen were: Reaction temperature [55–65 °C], reaction time [4–12 h] and substrate molar ratio [3–5 mol/mol (total FFA/tripalmitin)]. Good quadratic models were obtained for the incorporation of SDA and oleic acid. Optimal conditions generated from the models were determined as 60 °C; 8 h, 4 mol/mol for temperature, time and substrate molar ratio, respectively. The models were verified at optimum conditions and furthermore scale-up synthesis of structured lipids (SLs) was performed. Stearidonic and oleic acid contents of the SL from scale-up production were found to be 2.0 and 22.9 mol/100 mol total FA respectively, with 46.2 mol/100 mol total FA of palmitic acid content located at sn-2 position. Besides, oxidative stability and melting profile of final SL were determined for characterization. SL had 6.1 h of induction time, and also had a wider melting range compared with tripalmitin.     

Novel High-Speed High Pressure Torsion Technology for Obtaining Fe-Mn-Si-Cr Shape Memory Alloy Active Elements

This paper introduces an adapted high-speed high pressure torsion (HS-HPT) method of severe plastic deformation applied for obtaining shape memory alloy (SMA) active elements with revolution symmetry, able to develop axial displacement/force. Billets with circular crown forms were cut from Fe-28Mn-6Si-5Cr (mass%) SMA ingots and, by means of HS-HPT technology, were directly turned into modules, with truncated cone shell configurations. This process was performed, during time intervals of seconds, under the effect of high pressure (up to 1 GPa) cumulated with high rotation speed (hundreds of rotations per minute) applied on the active surfaces of sintered-carbide anvils, specially designed for this purpose. Due to pressure and friction, generated by rotation, the entire sample volume is heated and simultaneously deformed to final shape. During the process, microstructure fragmentation occurred enabling to obtain (ultra)fine grains and nanocrystalline areas, in spite of the heat developed by friction, which was removed by conduction at the contact surface between sample and anvils, before the occurrence of any recrystallization phenomena. When compressed between flat surfaces, the truncated cone modules developed a superelastic-like response, unique among Fe-Mn-Si base SMAs and, when heated in compressed state, they were able to develop either axial strokes or recovery forces by either free or constrained recovery shape memory effect (SME), respectively. By means of optical (OM) and scanning electron microscopy (SEM) marked structural changes caused by HT-HPT were revealed, along with fine and ultrafine crystalline grains. The presence of stress-induced ε-hexagonal close-packed (hcp) martensite, together with nanocrystalline areas were confirmed by x-ray diffraction.     

Synthesis, Electrical and Magnetic Characterization of Polyacrylamide Hydrogels Including NiFe2O4 Nanoparticles

This study investigates synthesis and characterization of polyacrylamide (PAAm) hydrogels containing magnetic NiFe₂O₄ nanoparticles. Structural, electrical, and magnetic characterization of the gels have been performed with X-ray powder diffractometry, scanning electron microscopy, DC conductivity, magnetization and fluorescence spectroscopy techniques. Fluorescence and electrical measurements show that nanoparticles have got trapped in the gel so it cannot move through the gel even if the gel is swollen and the voltage is applied. It was observed that the presence of NiFe₂O₄ nanoparticles makes the gel more homogeneous. Magnetization measurements reveal that NiFe₂O₄ nanoparticles have superparamagnetic behavior and total magnetization of the gel does not change as the swelling ratio increases. These features make the gel very suitable for applications like magnetic adsorbents.