Polyethylene glycol conjugates with linkers of varying acid-sensitivity were prepared by reacting five maleimide derivatives of daunorubicin containing an amide bond (1) or acid-sensitive carboxylic hydrazone bonds (2-5) with alpha-methoxy-poly(ethylene glycol)-thiopropionic acid amide (MW 20000) or alpha,omega-bis-thiopropionic acid amide poly(ethylene glycol) (MW 20000). The polymer drug derivatives were designed to ...

Salicylate-based poly(anhydride-esters), collectively referred to as PolyAspirin, hydrolytically degrade into salicylic acid, a nonsteroidal anti-inflammatory drug (NSAID). The variations of the poly(anhydride-ester) investigated in this article are linked by adipic acid, suberic acid, or sebacic acid. To elucidate the erosion mechanism of these polymers, water uptake, mass loss, contact angle, ...

Multiblock terpolymer of poly(L-lactic acid)/poly(ethylene oxide)/poly(L-aspartic acid), (PLLA/PEO/PAsp) was synthesized by ring opening polymerization of beta -benzyl L-aspartate N-carboxyanhydride, Asp(OBzl)-NCA with alpha-omega -hydroxy terminated triblock PLLA/PEO/PLLA copolymer. The resulting multiblock terpolymer was characterized by several techniques including Fourier transform infrared spectroscopy and differential scanning calorimetry.(1)H nuclear magnetic resonance spectra indicated ...

Pseudomonas corrugata was selected from a screening process for the bioconversion of inexpensive soy molasses into medium-chain-length poly(hydroxyalkanoates) (mcl-PHA). We obtained yields of 1.5 g cell dry weight (CDW)/l culture with growth medium supplemented with 2% (w/v) soy molasses, and of an average of 3.4 g CDW/l with 5% (w/v) ...

The analysis of alkyl alkylphosphonic acids, the degradation products of V and G nerve agents as VX, Sarin or Soman, is an important task for the verification of compliance to the Chemical Weapons Convention. The detection of these contaminants at low concentration levels is often difficult in complex matrices due ...

The objective of this study was to evaluate the effectiveness of a self-etching primer, Transbond Plus Self Etching Primer (TSEP, 3M Unitek), and a non-rinse conditioner (NRC, Dentsply DeTrey) for bonding brackets, compared with the acid-etch technique. The brackets were bonded to extracted premolars using Transbond XT (3M Unitek). One ...

The micellization properties of carboxy-modified Pluronics P85 (poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers) are investigated by means of a molecularly realistic self-consistent-field theory. We consider the, so-called, carboxylic acid end-standing P85 (CAE-85) case where the carboxylic group is located at the end of both PEO parts and the carboxylic ...

With the extent of international usage and the critical role phosphine gas (PH3) plays in commercial pest control, identification of the residual components deposited during fumigation is mandatory. It has been postulated that these infrequent residues are primarily composed of phosphoric acid or reduced forms of phosphoric acid [hypophosphorous acid ...

The poly(D,L-lactic acid)-block-(ligand-tethered poly(ethylene glycol)) copolymer was explored to engineer poly(D,L-lactic acid) (PLA) material to promote chondrocyte attachment and growth. The poly(D,L-lactic acid)-block-poly(ethylene glycol) copolymer (PLE) was synthesized by a coupling reaction between PLA and poly(ethylene glycol) (PEG) (M(n) 1000, 2000, and 4000 respectively), with the use of 4,4'-methylenediphenyl diisocyanate ...

This study demonstrates that boronic acid-containing polymers coated onto solid support function as synthetic mitogens for mouse lymphocytes. The polymer was synthesized by radical copolymerization of 3-acrylamidophenylboronic acid with dimethylacrylamide (poly(AAPBA-DMAA)). The boronic acid in the trigonal form in the copolymer activated lymphocytes, probably by crosslinkage to glycoprotein moieties on ...

OBJECTIVE: To evaluate in vitro the efficacy of a new anti-erosion desensitizing toothpaste to inhibit enamel surface softening by a dietary acid, and promote re-hardening of artificial erosive lesions. METHODOLOGY: The ability of the toothpaste to inhibit formation and promote repair of erosive lesions in human enamel has been investigated. ...

INTRODUCTION: Biodegradable polyester scaffolds have proven useful for growing neointestinal tissue equivalents both in vitro and in vivo. These scaffolds allow cells to attach and grow in a 3-dimensional space while nutrient flow is maintained throughout the matrix. The purpose of this study was to evaluate different biopolymer constructs and ...

OBJECTIVES: Comparative assessment of the failure rate of molar tubes bonded to first and second molars with a self-etching primer and conventional acid-etching. MATERIAL AND METHODS: Four hundred forty-four molar tubes (246 first molar tubes and 198 second molar tubes) were bonded, using a split-mouth design, on 62 patients (23 ...

The aim of this study was to evaluate by dispersive Raman spectroscopy the mineral and organic components of human dentin before and after laser irradiation and acid etching. The occlusal enamel of six non-carious human third molars was removed providing 6 dentin discs, which were divided in four quadrants each ...

During and after an erosive challenge, behavioral factors play a role in modifying the extent of erosive tooth wear. The manner that dietary acids are introduced into the mouth (gulping, sipping, use of a straw) will affect how long the teeth are in contact with the erosive challenge. The frequency ...

The mineral in our teeth is composed of a calcium-deficient carbonated hydroxyapatite (Ca10-xNax(PO4)6-y(CO3)z(OH)2-uFu). These substitutions in the mineral crystal lattice, especially carbonate, renders tooth mineral more acid soluble than hydroxyapatite. During erosion by acid and/or chelators, these agents interact with the surface of the mineral crystals, but only after they ...

The investigated polymers, poly(sebacic acid-co-ricinoleic acid) containing > or =70% ricinoleic acid, may be injected via a 22 gauge needle and become gel upon contact with aqueous medium, both in vitro and in vivo. Various properties of the polymers including viscosity, thermal analysis, and in vivo behavior, before and after ...

Novel polyester-co-polyether dendrimers consisting of a hydrophilic core were synthesized by a combination of convergent and divergent syntheses. The core was synthesized from biocompatible moieties, butanetetracarboxylic acid and aspartic acid, and the dendrons from PEO (poly(ethylene oxide)), dihydroxybenzoic acid or gallic acid, and PEG monomethacrylate. The dendrimers, Den-1-(G 2) (second ...

The Brazilian phosphate fertilizer is obtained by wet reaction of igneous phosphate rock with concentrated sulphuric acid, giving as final product, phosphoric acid and dehydrated calcium sulphate (phosphogypsum) as by-products. Phosphoric acid is the starting material for triple superphosphate (TSP), single superphosphate (SSP), monoammonium phosphate (MAP) and diammonium phosphate (DAP). ...

The effects of lysine (Lys), monosodium glutamate (GluNa), glycine, alanine and epsilon-poly(L-lysine) (PL) with different degrees of polymerization on the gelatinization behavior of potato starch granules were investigated by DSC, viscosity and swelling measurements, microscopic observation, and measurement of the retained amino acid amount to clarify the contribution of the ...

This study aimed to evaluate the susceptibility of eroded enamel to brushing abrasion performed by manual, power or sonic toothbrushes. Bovine enamel samples were subjected to 5 cycles, each consisting of 5 min demineralisation, 15 min remineralisation and 10 min brushing in a machine. Toothbrushing with the activated electric devices ...

A novel photo-cured amino-acid-constructed glass-ionomer cement system has been developed. Glutamic acid- and beta-alanine-based methacrylate and acrylate derivatives were synthesized, characterized and used to construct the polyalkenoic acids and formulated with water and Fuji II glass filler to form self-cured cement. Compressive strength (CS) of the cement and viscosity of ...

The aim of this study was to determine whether a tooth cream containing casein/calcium phosphate (CasCP) protects enamel against erosion. Sixty bovine enamel specimens were prepared for profilometry and distributed into five groups. Specimens were rinsed with artificial saliva interrupted by 1% citric acid (pH 2.3) for 30 s 6 ...

A novel biocompatible polyelectrolyte complex multilayer (PECML) was successfully prepared using hyaluronic acid (HA) and poly-l-lysine (PLL). The formation of PECML through the electrostatic interaction of HA as a polyanion and PLL as a polycation was confirmed by contact angle measurement, ESCA analysis and HA content analysis. According to the ...

OBJECTIVE: The purpose of this study was to characterize the etching behavior of titanium in concentrated sulfuric acid and discuss its application on surface modification of titanium for biological use. METHODS: Commercially pure titanium (cpTi) plate was etched in 48% H2SO4 at RT -90 degrees C for 0.25-8 h. The ...

Poly (lactic-co-glycolic acid) (PLGA) microspheres containing all-trans retinoic acid (atRA) were prepared by emulsion/solvent evaporation technique. PLGA (50:50) with inherent viscosities of 0.17 and 0.39 dL g(-1) was used. Polyvinyl alcohol (PVA) or PVA and sodium oleate (SO) combinations (4:1) were used to stabilize the emulsions. The effect of polymer ...

Sports drinks are becoming increasingly popular as we are all being encouraged to adopt a healthier lifestyle with regular exercise. However, many of these products are based on acidic fruits and may contribute to erosion. The aim of this study was to screen a number of these products for their ...

Nanocrystalline hydroxyapatite (nHA) can be mixed with phosphoric acid to form a brushite cement; a degradable inorganic bone filling material. nHA was precipitated from reactants of calcium to phosphate (Ca/P) ratio 0.8 to 2.0 and mixed with phosphoric acid, which resulted in the formation of a brushite cement. Cement was ...

We describe a simple, potentially low-cost, amperometric, enzyme-amplified, sandwich-type immunoassay, monitoring IgG at a concentration as low as approximately 7 pg/mL with a dynamic range of 10(4). The assay utilizes a screen-printed carbon electrode on which a redox hydrogel and avidin are co-electrodeposited. To neutralize nonspecifically binding positively charged microdomains ...

A basic host polymer exhibiting pH-regulatable saccharide recognition has been investigated. Poly(m-ethynylpyridine) bearing dialkylamino groups forms helical complexes with saccharides to show induced circular dichroism (ICD). When trifluoroacetic acid was titrated on these complexes, the ICD was gradually enhanced until the amount of the acid reached ca. 0.5 molar equivalence ...

We have developed a one-step, hydrofluoric acid-free hydrothermal etching method that not only produces bismuth nano/micrometer-sized spheres but also prepares porous silicon with vertical holes. By controlling the heating temperature and time, nanoscale vertical-channeled porous silicon can be received. Our result indicated that the Bi clusters were formed first on ...

Despite worldwide clinical use of bio-absorbable devices for internal fixation in orthopaedic surgery, the degradation behaviour and tissue replacement of these implants are not fully understood. In a long-term experimental study, we have determined the patterns of tissue restoration 36 and 54 months after implantation of polyglycolic acid and poly-laevo-lactic ...

The morphology and miscibility of semi-interpenetrating polymer networks (semi-IPN) prepared with poly(styrene-co-methacrylic acid) [P(S-co-MAA)] of different carboxylic acid contents and poly(epsilon-caprolactone) (PCL) have been studied by ESR spin-label method. The ESR spectra of spin-labeled PCL showed one motional component at any specific temperature. It indicated that the spin-labeled molecules were ...

The elimination or minimization of non-specific protein adsorption from serum is critical for the use of surface plasmon resonance (SPR) sensors for in vitro and in vivo analysis of complex biological solutions. The ultimate goals in this application are to minimize non-specific adsorption of protein and to maximize analyte signal. ...

New unsaturated polyesters of poly(fumaric acid-glycol-dodecanedioic acid) P(FA-GLY-DDDA) copolymers, poly(fumaric acid-glycol-brassylic acid) P(FA-GLY-BA) copolymers, poly(fumaric acid-glycol-tetradecanedioic acid) P(FA-GLY-TA) copolymers and poly(fumaric acid-glycol-pentadecanedioic acid) P(FA-GLY-PA) copolymers were prepared by melt polycondensation of the corresponding mixed monomers: fumaric acid, glycol and one of C(12-15) dibasic acids. The copolymers were characterized by FT-IR, ...

Oxalic acid and its metal oxalate salts have been used extensively in dentistry in a range of applications: as desensitisers, in cavity preparation, and as bonding agents. This study investigated the influence of oxalic acid upon the working time, initial setting time, 24-h hardness and compressive strength of a glass-ionomer ...

The ability to monitor etching solutions using a spectroscopy directly through existing Teflon lines in electronic industries is highly beneficial and offers many advantages. A monitoring method was developed using near-infrared (NIR) measurements with Teflon tubing as a sample container for the quantification of components in the indium-tin-oxide (ITO) etching ...

Concept of creating mechanical retention for bonding through crystal growth has been successfully achieved in the present study. By using polyacrylic acid, sulphated with sulphuric acid as etchant, abundant crystal growth was demonstrated. Keeping in view the obvious benefits of crystal growth technique, the present SEM study was aimed to ...

Sea ice occurs abundantly at the polar caps of the Earth and, probably, of many other planets. Its static and dynamic properties that may be important for prebiotic and early biotic reactions are described. It concentrates substrates and has many features that are important for catalytical actions. We propose that ...

Micropatterns of silica on a gold substrate were generated by a biomimetic approach, namely, the biosilicification of silicic acids. The procedure consists of three simple steps: pattern generation of a polymerization initiator, (BrC(CH(3))(2)COO(CH(2))(11)S)(2), by microcontact printing; surface-initiated, atom-transfer radical polymerization of 2-(dimethylamino)ethyl methacrylate (DMAEMA) from the patterned area; and polycondensation ...

OBJECTIVES: The aim of this study was to synthesize a novel ampiphilic polyalkenoic acid copolymer based on acrylic acid and a methacrylic macromonomer of Triton X-100 and determine the efficacy of the novel copolymeric polyalkenoic acid in the formation of glass-ionomer cements. METHODS: Two water soluble copolymers of acrylic acid ...

Poly(ethylene glycol)-b-poly(5-benzyloxy-trimethylene carbonate-lactic acid) copolymers (PEG-b-P(BTMC-LA)) were synthesized by ring-opening polymerization of lactide and 5-benzyloxy trimethylene carbonate in the presence of mono-hydroxyl poly(ethylene glycol) with diethyl zinc as catalyst. They were further converted into deprotected copolymers with the pendant hydroxyl groups by hydrogenolysis in the presence of Pd(OH)2/C, and finally ...

Polymeric micelles based on poly(L-lactide)-b-poly(2-ethyl-2-oxazoline)-b-poly(L-lactide) (PLLA-PEOz-PLLA) ABA triblock copolymers were designed as intracellular drug carriers. The PLLA-PEOz-PLLA micelles adopt a "flower-like" arrangement with A-blocks at the core and a B-block on the shell under neutral condition. The deformation of the core-shell structure is then promoted by the aggregation of PEOzs ...

The pseudobioaffinity chromatography with L-histidines immobilized onto poly(ethylene-vinyl alcohol) hollow-fiber membranes was studied for a selective purification of anionic oligosaccharides. Oligoglucuronans with different degrees of polymerization and acetylation, prepared by an enzymatic degradation of bacterial polyglucuronic acid, were used as models. The adsorption and elution parameters were studied to optimise ...

Blank and bovine serum albumin (BSA)-loaded microspheres based on poly(lactic-acid-alt-glycolic acid) (D,L-PLGA50) and poly(epsilon-caprolactone)-b-poly(lactic-acid-alt-glycolic acid) (PCL-b-D,L-PLGA50) were successfully fabricated using water-in-oil-in-water (w/o/w) double-emulsion extraction/evaporation technique. In vitro degradation of the blank microspheres was characterized by techniques including nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC) ...

Thiolated polymers or designated thiomers are mucoadhesive basis polymers, which display thiol bearing side chains. Based on thiol/disulfide exchange reactions and/or a simple oxidation process disulfide bonds are formed between such polymers and cysteine-rich subdomains of mucus glycoproteins building up the mucus gel layer. Thiomers mimic therefore the natural mechanism ...

BACKGROUND: Dental erosion is highly prevalent today, and acidic drinks are thought to be an important cause. The aim of the present investigation was to determine the erosive potential of a range of common beverages on extracted human teeth. METHODS: The beverages were tested for their individual pHs using a ...

The purpose of this study was to investigate the interfacial interaction of tartaric acid with hydroxyapatite and enamel. Hydroxyapatite particles were mixed with 15% (w/v) alcohol-aqueous (1:1) solution of tartaric acid for 72 h. After the mixture, the filtrate was separated from the solid. The filtrate, the solid, hydroxyapatite, and ...

Phosphoric acid esters (PAEs) have been used as a self-etching primer for composite-to-enamel bonding in adhesive dentistry. However, the chemical mechanism of their interactions with hydroxyapatite (HA) is not clear. In the present study, HA particles were mixed with Resulcin AquaPrime (Merz Co.) priming agent that contains a mixture of ...

OBJECTIVES: To assess the antimicrobial effect of acid etching or a triclosan-containing compomer on the cultivable microflora of incompletely excavated dentinal carious lesions. METHODS: Thirty detinal lesions were opened with a diamond burr. Subsequent to removal of the softened biomass a sample of dentin was taken from the cavity floor ...