Amino acid analysis

The process and apparatus for qualitative and quantitative analysis of the amino acid content of a biological sample are presented. The sample is deposited on a cation exchange resin and then is washed with suitable solvents. The amino acids and various cations and organic material with a basic function remain on the resin. The resin is eluted with an acid eluant, and the eluate containing the amino acids is transferred to a reaction vessel where the eluant is removed. Final analysis of the purified acylated amino acid esters is accomplished by gas-liquid chromatographic techniques

Testing procedures for carbon fiber reinforced plastic components

Tests for studying the basic material are considered and quality control investigations involving preimpregnated materials (prepreg) are discussed. Attention is given to the prepreg area weight, the fiber area weight of prepregs, the resin content, volatile components, the effective thickness, resin flow, the resistance to bending strain, tensile strength, and shear strength. A description of tests conducted during the manufacturing process is also presented, taking into account X-ray methods, approaches of neutron radiography, ultrasonic procedures, resonance methods and impedance studies

2-aminophenols containing electron-withdrawing groups from N-aryl hydroxylamines

Reaction of substituted N-aryl hydroxylamines with methanesulfonyl chloride, p-toluenesulfonyl chloride, or trifluoromethanesulfonic anhydride under basic conditions leads to the rearranged 2-aminophenols (45-94%). The overall reaction sequence can be performed using polymer-supported sulfonyl chloride resin allowing for the effective conversion of N-aryl hydroxylamines to the 2-aminophenols without the need for chromatography

The stability of new transparent polymeric materials: The epoxy trimethoxyboroxine system. Part 1: The preparation, characterization and curing of epoxy resins and their copolymers

The effects of resin composition, curing conditions fillers, and flame retardant additives on the flammability of diglycidyl ether of bisphenol-A (DGEBA) as measured by the oxygen index is examined. The oxygen index of DGEBA cured with various curing agents was between 0.198 to 0.238. Fillers and flame retardant additives can increase the oxygen index dependent on the material and the amount used. Changes in the basic cured resin properties can be anticipated with the addition of noncompatible additives. High flame resistant epoxy resins with good stability and mechanical properties are investigated

PENGARUH PENGGODOKAN TERHADAP MONOMER SISA PADA ELEMEN GIGI TIRUAN RESIN AKRILIK

ABSTRAK Nama : Anna Fitria Rossa Program Studi : Kedokteran Gigi Judul : Pengaruh Penggodokan Terhadap Monomer Sisa pada Elemen Gigi Tiruan Resin Akrilik. Gigi tiruan resin akrilik terdiri dari basis dan elemen gigi tiruan. Elemen gigi tiruan yang paling sering digunakan adalah elemen gigi tiruan resin akrilik. Pada prosedur pembuatan gigi tiruan diperlukan proses polimerisasi dimana ikatan kimiawi antara elemen gigi tiruan dan basis terjadi melalui proses polimerisasi. Resin akrilik heat-cured dipolimerisasi menggunakan pemanasan air (penggodokan). Meskipun berbagai metode digunakan untuk memulai reaksi polimerisasi namun konversi monomer menjadi polimer tidak pernah sempurna dan selalu terdapat monomer yang tidak habis bereaksi (monomer sisa). Adanya monomer sisa pada resin akrilik berpotensi menyebabkan iritasi, peradangan, dan reaksi alergi pada mukosa mulut. Penelitian ini bertujuan untuk melihat jumlah monomer sisa pada elemen gigi tiruan resin akrilik setelah dilakukan penggodokan. Penelitian ini menggunakan elemen gigi tiruan resin akrilik merk GC Permacryl China dan Basic. Spesimen berjumlah 12 spesimen dari 2 merk yang berbeda. Spesimen dari setiap merk di bagi menjadi 3 spesimen yang dilakukan penggodokan dan 3 spesimen tidak dilakukan penggodokan. Pengukuran monomer sisa menggunakan Gas Kromatografi dengan jenis detektor Flame Ionization Detector (FID). Analisis statistik pada penelitian ini menggunakan uji t-test independent. Hasil uji t-test independent menunjukkan bahwa tidak ada perbedaan yang bermakna (p>0.05) antara elemen gigi tiruan resin akrilik merk GC Permacryl China dan Basic yang dilakukan pengodokan dan tanpa penggodokan. Dapat disimpulkan bahwa tidak terdapat pengaruh penggodokan terhadap monomer sisa elemen gigi tiruan resin akrilik dan tidak terdapat perbedaan jumlah monomer sisa antara elemen gigi tiruan resin akrilik merk GC Permacryl China dan dan merk Basic. Kata Kunci : Elemen gigi tiruan resin akrilik, monomer sisa, penggodokan, gas kromatografi flame ionization detector ABSTRACT Name : Anna Fitria Rossa Program Study : Dentistry Title : The Effect of Curing to Residual Monomer on Resin Acrylic Artificial teeth Resin acrylic prosthesis consist of denture base and artificial teeth. The most common use of artificial teeth is from resin acrylic. One of step in procedure to make a prosthesis is polymerization which chemical bound between artificial teeth and denture base occur with polymerization. Resin acrylic heat cured was polymerized using wet heat (curing). Although many methods was used in polymerization but the conversion of monomer to be polymer never be completed and always conduct of residual monomer. The residual monomer of resin acrylic could lead to irritation, inflammation and allergic reaction of oral mucous. This study was aimed to analyze the effect of residual monomer on resin acrylic artificial teeth after curing. This study was using resin acrylic artificial teeth GC Permacryl China and Basic. Specimens was 12 from different brands. Specimens of each brand was divided into 2 groups which consist of 3 specimens. 3 specimens was curing and the others without curing. The measuring of residual monomer was using gas chromatography with Flame Ionization Detector (FID) system. The data of this study was analyzed using t-test independent. The result shown that there was no significant different (p > 0,05) between artificial teeth of Permacryl and Basic with curing and without curing. It can be concluded that there was no effect of curing to residual monomer of resin acrylic artificial teeth Permacryl and Basic brands. Keywords: Resin acrylic artificial teeth, residual monomer, curing, gas chromatography FI

Weak anion-exchange hypercrosslinked sorbent in on-line solid-phase extraction-liquid chromatography coupling to achieve automated determination with an effective clean-up

A mixed-mode polymeric sorbent was on-line coupled to liquid chromatography (LC) for the first time and applied it to the selective solid-phase extract a group of pharmaceuticals in complex environmental water samples. The mixed-mode polymeric sorbent is a high-specific surface area hypercrosslinked polymer resin (HXLPP) in the form of monodisperse microspheres further modified with 1,2-ethylenediamine (EDA) moieties. These properties allows its application as a weak anion-exchange (WAX) sorbent in the on-line solid-phase extraction (SPE) coupling. The on-line SPE-LC method developed using the HXLPP-WAX sorbent was successfully applied to percolate a large volume of ultrapure (500 ml), river (250 ml) and effluent sewage (100 ml) water samples. In all the cases, the HXLPP-WAX resin provided near total recoveries of the most acidic compounds studied and clean chromatograms. This is because the ion-exchange interactions enable a washing step to be added to the SPE protocol that removes the compounds with weak acidic, neutral and basic properties from the sample matrix

PENGARUH SEDUHAN KOPI ARABIKA GAYO TERHADAP PERUBAHAN WARNA ELEMEN GIGI TIRUAN RESIN AKRILIK YANG BERBEDA MEREK

ABSTRAKNama:Asri MaulinaFakultas:Kedokteran GigiJudul:Pengaruh Seduhan Kopi Arabika Gayo Terhadap Perubahan Warna Elemen Gigi Tiruan Resin Akrilik Yang Berbeda MerekSalah satu sifat gigi tiruan resin akrilik adalah penyerapan cairan, termasuk larutan berwarna yang dapat mempengaruhi perubahan warna gigi tiruan resin akrilik. Penelitian eksperimen ini bertujuan untuk mengetahui perbedaan stabilitas warna gigi tiruan resin akrilik yang berbeda merek setelah perendaman dalam minuman kopi arabika gayo. Penelitian ini menggunakan 20 spesimen (10 spesimen gigi tiruan resin akrilik Hard dent dan 10 spesimen Basic Germany). Semua spesimen direndam dalam minuman kopi arabika gayo selama 4 hari, pengukuran perubahan warna untuk setiap spesimen diukur sebelum dan setelah 4 hari perendaman menggunakan sistem Munsell Soil Color Chart (hue, value, chroma). Data analisis statistik setiap kelompok gigi tiruan resin akrilik menggunakan Wilcoxon dan Mann-Whitney test (

The binding of glycosaminoglycans to peptides : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Biochemistry at Massey University

The overall aim this study was to examine the possibility of using immobilised polypeptide chains to fractionate/separate Glycosaminoglycans (GAG's) from mixtures. Initially individual samples of three GAG classes (chondroitin sulphate, dermatan sulphate and heparin) were characterised to establish purity and provide basic information. Once these samples had been characterised the samples were treated as standards. Three short poly-l-lysine (PLL) chains with defined length and orientation were synthesized. As a control a PLL chain with 633 residues was immobilised. The interaction of the GAG standards with these resins did not replicate published solution binding behaviour of longer PLL chains. This suggested a different mode of binding. The interaction of two lengths of PLL (126 and 633 residues) and the K8G peptide with the GAG standards in solution was investigated. These studies demonstrated that the mode of binding of GAG's to short PLL chains was radically different to the earlier reported solution binding studies. β-Strand dominates with the short PLL chains instead of α-helix established in the published solution binding studies. The interaction of two peptides PCI (264-283) and thrombospondin peptide with the GAG standards was studied using circular dichroism spectroscopy. In the case of the PCI peptide, each GAG induced different secondary structures. Chondroitin sulphate and heparin induced an α-helix, whereas dermatan sulphate gave β-strands. Heparin and dermatan sulphate induced double the amount of secondary structure compared to chondroitin sulphate. The strength of the interaction of GAG's with the peptide was also measured by the concentration of salt required to dissociate 50% of the complex. The figures for dermatan sulphate and heparin were found to be 0.1 and 0.3 M salt respectively. The binding of the GAG standards to the thrombospondin peptide did not elicit any detectable change in conformation of the peptide. Critical examination of published material on the interaction of GAG's (principally heparin) with short peptides, prompted the writer to propose two new complementary models. The first model examines binding in terms of the conformation of the peptide induced by binding to the GAG. It is composed of three components, the periodicity of polar and nonpolar residues within the peptide sequence, the spacing of pairs of basic residues and the spacing of pairs of acidic and basic residues. This model is successfully able to rationalise the binding behaviour of a number of GAG/peptide interactions in terms of the dominant secondary structure and the biological activity. The model is able to make a number of specific predictions. The second model examines the strength of the interaction between heparin and peptides containing the proposed consensus sequences for GAG binding sites. A significant correlation between the binding strength and an attribute derived from the sequence of the peptide was found using only one assumption. The assumption was that the peptides in the correlation bound to heparin with significant levels of β-strand. For the first time it is possible to rationalise the behaviour of GAG/peptide interactions in a coherent manner. The design of peptides that are capable of binding to specific GAG's now seems possible

Elastomer coated filler and composites thereof comprising at least 60% by weight of a hydrated filler and an elastomer containing an acid substituent

The impact resistance of flame retardant composites, especially thermoplastic molding: compounds containing over 60% hydrated mineral filler such as Al(OH)3 or Mg(OH)2 as improved by coating the filler with 1 to 20% of an elastomer. The composite will fail by crazing or shearing rather than by brittle fracture. A well bonded elastomeric interphase resulted by utilizing acidic substituted resins such as ethyl-hexyl acrylate-acrylic acid copolymers which bond to and are cross-linked by the basic filler particles. Further improvement in impact resistance was provided by incorporating 1 to 10% of a resin fiber reinforcement such as polyvinyl alcohol fibers that decompose to yield at least 30% water when heated to decomposition temperature