Evidence-based case reports and epidemiologic surveys have indicated an association between dental erosion and high consumption of acidulated carbonated beverages (ACBs). This study sought to monitor the effect of exposure to ACBs on the topography and geometrical profile of disassociated human dentition. Two representatives of ACBs, caramelized (ACCB) and non-caramelized ...

An optically active helical poly(phenylacetylene) was synthesized by the copolymerization of phenylacetylenes bearing optically active hydroxy or ester groups obtained by the kinetic resolution of a racemic phenylacetylene with lipase; the helix-sense was inverted from one helix to another by the further chemical modification of the hydroxy groups with achiral ...

In our previous study, a three-dimensional zein porous scaffold with a compressive Young's modulus of up to 86.6+/-19.9 MPa and a compressive strength of up to 11.8+/-1.7 MPa was prepared, and was suitable for culture of mesenchymal stem cells (MSCs) in vitro. In this study, we examined its tissue compatibility ...

Estimation of age-at-death for skeletonised forensic remains is one of the most significant problems in forensic anthropology. The majority of existing morphological and histological techniques are highly inaccurate, and show a bias towards underestimating the age of older individuals. One technique which has been successful in forensic age estimation is ...

Stereoblock poly(lactic acid) (sb-PLA) is incorporated into a 1:1 polymer blend system of poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA) that has a high molecular weight to study its addition effect on the stereocomplex (sc) formation of PLLA and PDLA. The ternary polymer blend films are first prepared by casting ...

In this work, six amino acid derived (L-leucinol, L-leucine, L-isoleucinol, L-isoleucine, L-valinol, and L-valine) polymeric chiral surfactants with carboxylate and sulfate head groups that were recently synthesized in our laboratory [30, 33, 35] are compared for the simultaneous enantioseparation of several groups of structurally similar analytes under neutral and basic ...

Poly-beta-hydroxyalkanoate (PHA) is a biodegradable polymer accumulated in intracellular granules by different bacterial species. Its physical and chemical properties are similar to those of petroleum-derived plastics. Material generated by the acid hydrolysis of wood was evaluated for use in the bacterial synthesis of PHA. Acid-hydrolyzed sawdust was prepared and adjusted ...

Polymer modified calcium phosphate cements made with cement powders of varying tetracalcium phosphate [TTCP] content were prepared using two different molecular weight fractions of poly(acrylic acid) at four different concentrations. The ratio of the precursors (TTCP:DCPA) in the cement powder was found to influence the initial setting which decreased with ...

Molecular simulation studies of the microstructure and of the proton transport properties of phosphoric acid solvated Nafion membrane are carried out. The ab initio calculations show that the phosphoric acid is a good solvent to promote the proton ionization of the sulfonic acid group, and only two phosphoric acid molecules ...

Poly(DL-lactic-co-glycolic acid) microspheres are prepared using a double-emulsion technique and are loaded with the model enzyme horseradish peroxidase (HRP). These microspheres can be used alone or as coatings for bioresorbable fibers that may be used as scaffolds for tissue regeneration applications. The present study focuses on the effect of the ...

Cancer treatment efficacy and safety of the environmentally sensitive polymeric micelle drug carriers were significantly increased by optimizing the number of ligands on their surface. These micelles were designed to target the cancerous tumors through the interaction between folate and its receptors that overexpress on the cancer cell membrane while ...

Lipase-catalyzed terpolymerizations were performed with the monomers trimethylolpropane (B3), 1,8-octanediol (B2), and adipic acid (A2). Polymerizations were performed in bulk, at 70 degrees C, for 42 h, using immobilized lipase B from Candida antartica (Novozyme-435) as a catalyst. To determine the substitution pattern of trimethylolpropane (TMP) in copolymers, model compounds ...

Covalently attached organic monolayers on etched silicon nitride (SixN4; x >/= 3) surfaces were prepared by reaction of SixN4-coated wafers with neat or solutions of 1-alkenes and 1-alkynes in refluxing mesitylene. The surface modification was monitored by measurement of the static water contact angle, XPS, IRRAS, AFM, and ToF-SIMS, and ...

OBJECTIVES: The consumption of acidic soft drinks continues to rise as do concerns regarding effects of frequent intake. The aim of the study was to determine the effect of acidic soft drinks containing food approved polymers, on dental enamel. METHODS: The study design was a single blind, randomised, five-treatment crossover ...

The escalating problems regarding the treatment of plastic waste materials have led to development of biodegradable plastics. At present, a number of aliphatic polyesters; such as poly[(R)-3-hydroxybutyrate] (PHB), poly(l-lactide), polycaplolactone, poly(ethylene succinate) and poly(butylene succinate) have been developed. Among these aliphatic polyesters, PHB is one of the most attractive since ...

We have found strong supporting evidence for the helical structures of single-stranded nucleic acids by stretching individual molecules of polyadenylic acid [poly(A)] and polycytidylic acid [poly(C)]. Analyzing the force versus extension data using a two-state elastic model in which random-coil domains alternate with rigid helical domains allows one to extract ...

Initiated chemical vapor deposition (iCVD) is presented as an all-dry synthesis and coating method for applying methacrylic acid copolymers as pH-responsive controlled release layers. iCVD combines the strengths of liquid-phase chemical synthesis with a precision solvent-free chemical vapor deposition environment. Copolymers of methacrylic acid and ethyl acrylate were confirmed by ...

Huperzine A loaded poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres were prepared by an oil/water (o/w) solvent evaporation technique. With a decrease of the ratio of o/w from 1 : 100 to 1 : 50, the encapsulation efficiency was reduced about 4%. Increasing the PVA concentration from 0.5 to 2% reduced the percentage ...

Novel cholic acid functionalized branched oligo/poly(epsilon-caprolactone)s were synthesized through the ring-opening polymerization of epsilon-caprolactone initiated by cholic acid with hydroxyl groups. The molecular weight of the branched polymers can be adjusted by controlling the feed ratio of the initiator cholic acid to the monomer epsilon-caprolactone. Comparing with linear homopolymer poly(epsilon-caprolactone) ...

Conservative techniques for treatment of discolored human enamel include in-office bleaching with heat-activated 35% hydrogen peroxide, Nightguard vital bleaching with 10% carbamide peroxide, and enamel microabrasion with 18% hydrochloric acid. OBJECTIVES: In this study, these bleaching techniques were performed on 30 extracted teeth to evaluate their effects on microhardness of ...

The drug release profiles of poly(dimer acid-dodecanedioic acid) P(DA-DDDA) copolymer containing 5% adriamycin hydrochloride (ADM) in vitro were evaluated. The biocompatibility of P(DA-DDDA) under mice skin was also evaluated, macroscopic observation and microscopic analysis demonstrated that the copolymer is biocompatible and well tolerated in vivo. Antitumor efficacy of P(DA-DDDA) copolymers ...

Inverse gas chromatography (IGC) has been used to characterise the surface properties of polycaprolactone (PCL) and poly(lactic acid) (PLA). The dispersive component of the surface free energy (gamma(S)(D)) was found to be very small for both of them--values close to 30 mJ/m(2) in the case of the PLA and ca. ...

To prepare sulfur-containing natural polymers effectively, several plant oils and 3,3'-thiodipropionic acid (TDP) have been used as carbon sources for the biosynthesis of copolymer poly[(3-hydroxybutyrate)-co-(3-mercaptopropionate)] [poly(3HB-co-3MP)] by a wild-type bacterium Cupriviadus necator H16. By using the plant oils, copolymer accumulation and incorporation of 3MP units are greater than those of ...

Molecularly imprinted polymers (MIPs) against fructosyl valine (Fru-Val), the N-terminal constituent of hemoglobin A1c beta-chains, were prepared by cross-linking of beta-D-Fru-Val-O-bis(4-vinylphenylboronate) with an excess of ethylene glycol dimethacrylate (EDMA) or trimethylolpropane trimethacrylate (TRIM). Control MIPs were prepared in analogy by cross-linking the corresponding vinylphenylboronate esters of fructose and pinacol. After ...

The presence of a hydroxyl group at the end of poly(3-hydroxyoctanoate) oligomers, noted PHO oligomers, is required to prepare diblock copolymers with improved properties by ring-opening polymerization of cyclic monomer as epsilon-caprolactone. Several chemical methods such as basic hydrolysis, acid-catalyzed reaction with APTS, and methanolysis were used to prepare well-defined ...

The melting behaviour and transport properties of straight chain alkanes mono- and difunctionalized with phosphonic acid groups have been investigated as a function of their length. The increase of melting temperature and decrease of proton conductivity with increasing chain length is suggested to be the consequence of an increasing ordering ...

Hyperbranched copolymers were prepared by the heat transesterification of 4-hydroxycinnamic acid (4HCA) and 3,4-dihydroxycinnamic acid (DHCA) with a high 4HCA composition dissolved in trifluoroacetic acid (TFA). The nanoparticles were formed after two homogeneous copolymer solutions were mixed in DMF and TFA, which are both good solvents for the copolymer P(4HCA-co-DHCA). ...

This paper reports on the synthesis, characterisation, and efficiency of a new intravenous conjugate of amphotericin B (AMB). Twelve molecules of AMB were attached to block copolymer poly(ethylene glycol)-b-poly(L-lysine) via pH-sensitive imine linkages. In vitro drug release studies demonstrated the conjugate (M(w)=26,700) to be relatively stable in human plasma and ...

A blend mixture of poly(epsilon-caprolactone) (PCL) and poly(ethylene oxide) (PEO) was electrospun to produce fibrous meshes that could release a protein drug in a controlled manner. Various biodegradable polymers, such as poly(l-lactic acid) (PLLA), poly(epsilon-caprolactone) (PCL), and poly(d,l-lactic-co-glycolic acid) (PLGA) were dissolved, along with PEO and lysozyme, in a mixture ...

PURPOSE: The purpose of this prospective randomized controlled clinical study was to evaluate the clinical performance of a "mild" two-step self-etching adhesive, Clearfil SE, in Class V restorations after 5 years of clinical functioning. MATERIALS AND METHODS: Twenty-nine patients received two or four restorations following two randomly assigned experimental protocols: ...

The capability of different organic acids to produce a derivative of PHB [poly(3-hydroxybutyric-co-3-hydroxyvaleric acid), P(3HB-co-3HV)] was examined in shake flask cultivations. Propionic and valeric acids demonstrated the potential to produce P(3HB-co-3HV) under nitrogen limiting conditions at 30 degrees C. The addition time and the initial concentration of valeric acid needed ...

The aim of this in vitro study was to investigate the effects of Er:YAG laser pretreatment procedures in fissure sealing. The fissures of 90 third molars were prepared in the mesial halves with Er:YAG laser (lambda = 2,940 nm, 250 mJ/pulse, 4 Hz, fluence 32 J/cm(2)) and acid etched. They ...

It is advantageous to incorporate controlled growth factor delivery into tissue engineering strategies. The objective of this study was to develop a three-dimensional (3D) porous tissue engineering scaffold with the capability of controlled releasing recombinant human bone morphogenetic protein-7 (rhBMP-7) for enhancement of bone regeneration. RhBMP-7 was first encapsulated into ...

The oxygen isotope ratio of CO(2) liberated from structural carbonate in tooth enamel apatite was measured at phosphoric acid reaction temperatures of 25 degrees C, 60 degrees C and 90 degrees C, and it was found that apparent acid fractionation factors for pristine enamel, fossilized enamel, and calcite follow different ...

This paperwork deals with the obtaining and characterisation of new acrylic cements for bone surgery. The final mixture of cement contains derivatives of methacryloyloxyethyl phosphate, methacrylic acid or 2-acrylamido-2-methyl-1-propane sulphonic acid. The idea of using these monomers is sustained by their ability to form ionic bonds with barium, which is ...

The aim of this in vitro study was to examine the effect of fluoride treatment on pellicle-covered enamel exposed to an acidic challenge simulating gastric reflux. Sixteen bovine and 16 human teeth were sectioned into four pieces, divided into four groups: (1) control, (2) 2-hour pellicle, (3) TiF(4), and (4) ...

The release of ions from a glass-ionomer glass, which in the polyacid matrix effects the cross-linking and setting of a cement, can be modelled and initiated by acid-treatment in a dilute acid. This study examined the effect of time of acetic acid leaching on the working time, setting time, and ...

Multi-purpose bonding performance of three kinds of newly synthesized phosphonic acid monomers was investigated. Methacryloxyalkyl or acryloxyalkyl phosphonoacetates of 6-MHPA, 6-AHPA, 10-MDPA were synthesized in 42.8-51.9% yields with a light yellow viscous liquid, and identified as new compounds by 1H NMR, IR, and elemental analysis. Conventional adhesive monomers, namely VBPA, ...

OBJECTIVE: The purpose of this study was to compare the reactivity of three dentifrice formulations on smear layer-covered root dentin surfaces, and the effects of the formulation treatments on resistance to acid softening and dentinal tubuli disclosure. METHODOLOGY: Commercial dentifrices, including Crest Cavity Protection Regular, Colgate Total, and a new ...

This study evaluated the effectiveness of acidic low-fluoride dentifrices compared to conventional neutral dentifrices. Enamel blocks were submitted to pH cycling and treatment with slurries of dentifrices containing 0, 275, 412, 550 and 1,100 microg F/g (pH 4.5 or 7.0), and also a commercial dentifrice (1,100 microg F/g) and a ...

Bonding to enamel has over 50 years of history. Efforts have been made to develop or introduce a simplified alternative, but enamel acid etching remains the most effective procedure for stable enamel bonding. Although acid etching is considered the most popular procedure in dentistry, there are characteristics that deserve special ...

In this paper we describe how to template a demixed monolayer into a spatially patterned inorganic replica. For this purpose a new amphiphilic monomer was synthesized which can be polymerized both in solution and in the monolayer of a Langmuir-Blodgett (LB) trough. Since it inhibits the crystallization of CaCO3, it ...

The developing leaf three of barley provides an excellent model system for the direct determination of relationships between amounts of waxes and cutin and cuticular permeance. Permeance of the cuticle was assessed via the time-course of uptake of either toluidine blue or (14)C-labelled benzoic acid ([(14)C] BA) along the length ...

Poly(ethylene terephthalate) (PET)/Clay hybrids were prepared via in situ polymerization, in which the clay was modified with 12-aminododecanoic acid (ADA). Three types of bifunctional compounds were introduced into the system, respectively, as compatibilizers between PET and ADA-Clay. The three compounds contain 1 degree, 2 degree, and 3 degree amino groups, ...

The electrospinning of stereocomplex nanofibers of high-molecular-weight poly(L-lactic acid) (PLLA)/poly(D-lactic acid) (PDLA) (PLLA/PDLA = 1:1) was carried out with chloroform as the spinning solvent. The stereocomplex nanofibers with diameters of 830-1400 and 400-970 nm were successfully obtained at voltages of -12 and -25 kV, respectively. Wide-angle X-ray scattering indicated that ...

OBJECTIVE: Although self-etching bonding systems (SES) are indicated to prepare dental enamel for bonding, concerns have been expressed regarding their effectiveness. The aim of this study was to analyze the etching pattern (EP) of nine SES in comparison with 35% and 34% phosphoric acid etchants (FA) on intact (IN) and ...

Development of fibrous matrices of bioceramic-biopolymer nanocomposite offers great potential in the field of bone regeneration and tissue engineering. However, in order to produce electrospun fibers with homogeneous structure, it is essential for the ceramic powder to be fine and to remain stable in suspension. Herein, we developed a novel ...

OBJECTIVE: The purpose of this study was to analyze dentinal surfaces that were exposed to acidic beverages, then treated with Nd:YAG laser and afterwards exposed to acidic beverages again. BACKGROUND DATA: Dentin hypersensitivity can result from surface erosion caused by acidic beverages, which exposes and enlarges the dentinal tubules. Nd:YAG ...

An efficient method for the liquid-phase combinatorial synthesis of N4-substituted 1,4-benzodiazepine-2,5-diones has been developed. Poly(ethylene glycol) (PEG) stepwise reacted with bromoacetyl bromide, a primary amine and 2-azidobenzoic acid to give a potential PEG-bound dipeptide, which was reduced by NaI / acetic acid, along with concurrent cyclization and cleavage of the ...

Carboxylated pyrrole (Pyr, a index)- and carbazole (Cbz, b index)-containing monomers 6-7a/b and 9a/b have been readily synthesized from the monobenzyl ester of L-glutamic acid and triamine 2 using Clauson-Kaas and amide coupling reactions. In contrast to Pyr-containing compounds 6-7a, and 9a, the three Cbz-containing monomers 6-7b, and 9b have ...