Evaluation of the effect of food and beverages on enamel and restorative materials by SEM and Fourier transform infrared spectroscopy.

OBJECTIVES: To examine different types of restorative materials used in children as well as primary and permanent teeth enamel when affected by erosive foods. MATERIALS AND METHOD: Buttermilk, fruit yoghurt, Coca-cola, fruit juice, Filtek Z-250, Dyract Extra, Fuji II LC, and Fuji IX and tooth enamel were used. Measurements were performed on 1-day, 1-week, 1-month, 3-month, 6-month time periods by using ATR-FTIR technique and surface of the specimens were examined with SEM. RESULTS: Permanent tooth showed the least change among human tooth samples when compared to restorative materials. Among filler materials, the most change was observed in Fuji IX. In terms of beverages the most changes on absorption peaks obtained from spectra were seen on the samples held in Coca-Cola and orange-juice. CONCLUSION: The exposure of human enamel and restorative materials to acidic drinks may accelerate the degradation process and so reduce the life time of filler materials at equivalent integral exposure times longer than three months. Clinical Relevance Erosive foods and drinks having acidic potential destroy not only tooth enamel but also restorative materials.

4-Chloro-2-[(4-chloro-benzyl-idene)amino]-phenol.

In the title Schiff base compound, C(13)H(9)Cl(2)NO, the mol-ecule displays an E conformation about the imine C=N double bond, with a dihedral angle of 8.09 (11)° between the two benzene rings. In the crystal, mol-ecules are linked by a single O-H⋯O hydrogen bond, giving one-dimensional chains which extend along (100).

3-Amino-4-[4-(dimethyl-amino)-phen-yl]-4,5-dihydro-1,2,5-thia-diazole 1,1-dioxide.

The title compound, C(10)H(14)N(4)O(2)S, exists in the amine tautomeric form. The dihedral angle between the benzene and thia-diazo-lidine rings is 66.54 (19)°. In the crystal, mol-ecules are linked by N-H⋯O and N-H⋯N hydrogen bonds into a layer parallel to the ac plane. The layers are further linked by C-H⋯O hydrogen bonds.

Antimicrobial activity of some sulfonamide derivatives on clinical isolates of Staphylococus aureus.

BACKGROUND: Staphylococcus aureus is a non-motile, gram positive, non-sporforming, facultative anaerobic microorganism. It is one of the important bacteria as a potential pathogen specifically for nosocomial infections. The sulfonamide derivative medicines are preferred to cure infection caused by S. aureus due to methicillin resistance. METHODS: Antimicrobial activity of four sulfonamide derivatives have been investigated against 50 clinical isolates of S. aureus and tested by using MIC and disc diffusion methods. 50 clinical isolate which collected from specimens of patients who are given medical treatment in Ondokuz Mayis University Medical School Hospital. A control strain of S. aureus ATCC 29213 was also tested. RESULTS: The strongest inhibition was observed in the cases of I [N-(2-hydroxy-4-nitro-phenyl)-4-methyl-benzensulfonamid], and II [N-(2-hydroxy-5-nitro-phenyl)-4-methyl-benzensulfonamid] against S. aureus. Compound I [N-(2-hydroxy-4-nitro-phenyl)-4-methyl-benzensulfonamid] showed higher effect on 21 S. aureus MRSAisolates than oxacillin antibiotic. Introducing an electron withdrawing on the ring increased the antimicrobial activity remarkably. CONCLUSION: This study may help to suggest an alternative possible leading compound for development of new antimicrobial agents against MRSA and MSSA resistant S. aureus. It was also shown here that that clinical isolates of 50 S. aureus have various resistance patterns against to four sulfonamide derivatives. It may also be emphasized here that in vitro antimicrobial susceptibility testing results for S. aureus need standardization with further studies and it should also have a correlation with in vivo therapeutic response experiments.

µ-Squarato-κO:O-bis-{[2-(2-amino-ethyl)pyridine-κN,N']aqua-nickel(II)} squarate 0.25-hydrate.

The asymmetric unit of title compound, [Ni(2)(C(4)O(4))(C(7)H(10)N(2))(4)(H(2)O)(2)]C(4)O(4)·0.25H(2)O, contains one-half of a squarate ligand, one-half of an uncoordinated squarate dianion, two 2-(2-amino-ethyl)pyridine ligands and one aqua ligand, all coordinated to an Ni(II) ion. The compound also contains 0.25 solvent water mol-ecules. The Ni(II) ion has distorted octa-hedral geometry. The squarate ligand adopts a µ-1,2 coordination mode, the intra-dimer Ni(II)⋯Ni(II) separation being 7.1442 (7) Å, while the other squarate unit acts as a counter-anion. The crystal structure is stabilized by inter-molecular O-H⋯O and N-H⋯O hydrogen-bond inter-actions, forming a three-dimensional network.

Spectrophotometric flow-injection analysis of mercury(II) in pharmaceuticals with p-nitrobenzoxosulfamate.

A new, simple and rapid spectrophotometric FI method for the accurate and precise determination of Hg(II) in pharmaceutical preparations has been developed. The method is based on the measuring the decrease of absorbance intensity of p-nitrobenzoxosulfamate (NBS) due to the complexation with Hg(II). The absorption peak of the NBS, which is decreased linearly by addition of Hg(II), occurs at 430 nm in 2x10(-4) moll(-1) HNO(3) as a carrier solution. Optimization of chemical and FI variables has been made. A micro column consisting of several packing materials applied instead of reaction coil was also investigated. A background level of Fe(III) maintained in reagent carrier solution with NBS was found useful for sensitivity and selectivity. Under the optimized conditions, the sampling rate was over 100 h(-1), the calibration curve obtained were linear over the range 1-10 mugml(-1), the detection limit was lower than 0.2 mugml(-1) for a 20 mul injection volume, and the precision [S(r)=1% at 2 mugml(-1) Hg(II) (n=10)] was found quite satisfactory. Application of the method to the analysis of Hg(II) in pharmaceutical preparations resulted a good agreement between the expected and found values.

Sodium p-nitrobenzoxasulfamate monohydrate.

The title compound, alternatively named sodium 6-nitro-3H-1,2,3-benzoxathiazole 2,2-dioxide monohydrate, Na+*C6H3N2O5S-*H2O, consists of chains of NaO7 units, with the seven donor-O atoms coming from two water molecules and five p-nitrobenzoxasulfamate anions. The seven-coordinate geometry around the Na+ ion is described as monocapped trigonal prismatic, but with a large distortion from ideal geometry. Each triangular face is defined by one O atom each from a water molecule, a nitro group and a sulfonyl group. An O atom from a sulfonyl group caps one of the square faces of the trigonal prism in an unsymmetrical fashion. The water molecules and one sulfonyl O atom are involved in bridging adjacent units, as is the nitro group of the anion. The sulfamate ions adopt an antiparallel alignment between the NaO7 units and are connected to each other by C-H...O and pi-pi interactions. The three-dimensional crystal structure is stabilized by a network of strong O-H...N hydrogen bonds.