Effect of Tannic Acid and Quercetin Antioxidants on Bond Strength of Resin Cement to Dentin after Internal Bleaching.

PURPOSE: To evaluate the influence of tannic acid and quercetin on the immediate microshear bond strength (µSBS) of two resin cements to dentin after internal bleaching. MATERIALS AND METHODS: The access cavity in eighty extracted maxillary incisors was internally bleached except the control groups. The labial surfaces were ground to expose a flat dentin surface. The specimens were randomly divided into eight groups (n=10) as follows: 1) Control/Dou; Doulink without bleaching, 2) Bl/Dou; Bleaching+Doulink, 3) Bl+Ta/ Dou; Bleaching+Tannic acid+Doulink, 4) Bl+Qu/Dou;Bleaching+Quercetin+Doulink, 5) Control/ PSA; Panavia SA without bleaching, 6) Bl/PSA;Bleaching+Panavia SA, 7) Bl+Ta/ PSA; Bleaching+Tannic acid+Panavia SA, 8) Bl+Qu+PSA; Bleaching+Quercetin+Panavia SA. After 24 hours, the µSBS of the specimens was tested and the obtained data were analyzed with two-way ANOVA and Tamhane test (p⟨0.05). RESULTS: The µSBS of Doulink groups were higher than the PSA groups (p⟨0.001). The µSBS of Bl+Ta/Dou and Bl+Qu/ Dou groups did not differ from Bl/Dou (p⟩0.05). The µSBS of Bl+Ta/PSA group was statistically significantly higher than the Bl/PSA group (p⟨0.001). There was no significant difference between µSBS of Bl+Qu/PSA and Bl/PSA groups (p=0.39). CONCLUSIONS: TA partially reversed the negative influence of internal bleaching on the µSBS of Panavia SA while quercetin did not increase the bond strength of both resin cements.

Effects of exogenous enzymes and application method on nutrient intake, digestibility and growth performance of Pelibuey lambs.

Pelibuey sheep is the main breed in the tropical and subtropical regions of Mexico, and high demand of sheep meat has favored the finishing of lambs in feedlots with diets containing high levels of grains. The objective of this study was to evaluate the effects of exogenous enzymes (EE) and application method on nutrient intake and digestibility and performance of growing Pelibuey lambs. Treatments were based on comparison of two different methods of adding an enzyme product (sprayed on the total mixed ration or applied orally to the lambs) versus control treatment (no added enzyme). Twenty-one Pelibuey lambs, weighing 15.7 kg (SD = 1.8 kg) initial body weight, were individually housed in shaded pens and assigned randomly to one of the three enzyme treatments. At the end of study (lasting for 45 days), three lambs from each treatment were randomly selected and adapted to a pants and harness designed for fecal collection to measure nutrient digestibilities. Total body gain and average daily gain were affected (P < 0.05) by supplemental EE. The application method of EE had significant (P < 0.05) effect on FCE and FCR, but no effects were observed on nutrient intake. Supplemental EE did improve (P < 0.05) the digestibilities of dry matter, organic matter, neutral and acid detergent fiber, but no differences were observed in crude protein digestibility. The application method of EE had significant (P < 0.05) effect on the digestibility of acid detergent fiber. Supplemental EE can improve body weight gain and nutrient digestibilities without affecting nutrient intake in Pelibuey lambs, but the results of feed conversion efficiency and acid detergent fiber digestibility depend on the application method used of the EE.

Synthesis and biological activity of some nucleoside analogs of hydroquinoline-3-carbonitrile.

Hydroquinoline acyclonucleosides 2, 4, 6a,b, 8a,b, 9a,b, and their corresponding N-alkyl derivatives (10-12) were obtained by the reaction of 1a,b with acetoxybutylbromide, (2-acetoxyethoxy)methyl bromide, 3-chloropropanol, 1,3-dichloro-2-propanol, epichlorohydrin, propargyl/allyl bromides in the presence of K(2)CO(3) in dry dimethylformamide (DMF). In a similar manner, reaction of 1a,b with glycosyl/galactosyl and lactosyl bromide afforded the corresponding N-nucloside derivatives 13a,b, 15a,b, and 17, respectively. Deacetylation of the N-nucleosides derivatives in the presence of Et(3)N/MeOH and few drops of water gave the deprotected derivatives 3, 5, 7a,b, 14a,b, 16a,b, and 18 in good yields, respectively. All the newly synthesized compounds are elucidated by infrared, (1)H, (13)C NMR and elemental analyses. Some of these compounds were screened for antimicrobial activities.

Synthesis and antimicrobial activity of some 2-pyridone nucleosides containing a sulfonamide moiety.

Glycosylation of 2-pyridonesulfonamide 1a,b with glycosyl/galactosyl bromide gave the corresponding glycosides 2a,b, 3a,b, 6a,b, and 7a,b, respectively. Deacetylation of the resulting glycosides gave the corresponding glycosides 4a,b, 5a,b, 8a,b, and 9a,b, respectively, in good yields. Furthermore, reaction of 2-pyridonesulfonamide 1b with lactosyl bromide gave a mixture the corresponding N, O-lactosides 10 and 11, which were deacetylated to give the corresponding glycosides 12 and 13, respectively. The structures of the new synthesized compounds were characterized by using IR, 1H, 13C NMR spectra, and microanalysis. Selected members of these compounds were screened for antimicrobial activity.

Milk yield and composition of crossbred Sahelian × Anglo-Nubian goats in the semi-intensive system in Mali during the preweaning period.

The aim of this study was to evaluate milk yield and its composition during the preweaning period for Sahelian goats (SG) and Anglo-Nubian (AN) crossbred depending on some factors. The experiments were conducted from January to December 2008 for 44 suckled and hand-milked does, randomized, and divided into two equal groups: SG (n = 22) and F(1) Anglo-Nubian × Sahelian goats (1/2AN; n = 22). The does and their offsprings were kept in a pen where they stayed indoors for 45 days before they were allowed outdoors when the weather was suitable. Each category received supplemental feeds depending on the season (rainy season, dry cold season, and dry hot season). The average daily milk yield was recorded weekly from parturition to 100 days of age. Individual milk samples were taken for chemical analysis in connection with the yield measurements twice per month from the fourth week of lactation throughout the different seasons (rainy, cold dry, and hot dry). The daily milk yield differed between breed types (P = 0.001) during the preweaning, while the effect of kids' sex on daily milk production was not significant. Litter size affected milk yield up to day 60 (P = 0.032) where does with twins producing more milk than those with single kid. However, at day 100, both groups had similar (P = 0.001) milk production. Total milk yield at weaning increased by 103 % in 1/2AN over SG. The highest concentration of total solids of milk was (12.76 %) recorded in the hot dry season. The results of this study indicate that crossbreeding native Sahelian goats with high potential Anglo-Nubian buck improved milk production and its composition.

Understanding Periodic Dislocations in 2D Supramolecular Crystals: The PFP/Ag(111) Interface.

In-plane dislocation networks arise in both inorganic and organic films as a way of relieving the elastic strain that builds up at the substrate interface. In molecule/surface systems, supramolecular interactions are weak and more complex (compared to the atomic bonds in inorganic films), and their interplay with molecule-substrate interactions is very subtle, making it difficult to single out the driving force for a nanoscale dislocation pattern. On the basis of a combined experimental and theoretical work, we here show that periodic dislocations in a molecular PFP film are mainly driven by the optimization of molecule-substrate interactions. Compared to inorganic networks however, it implies a much lower energy imbalance, allowing a thermally induced transition from a low-energy strain dislocation pattern to a high-energy incommensurate moiré.

Lifshitz transition across the Ag/Cu(111) superlattice band gap tuned by interface doping.

The two-dimensional, free-electron-like band structure of noble metal surfaces can be radically transformed by appropriate nanostructuration. A case example is the triangular dislocation network that characterizes the epitaxial Ag/Cu(111) system, which exhibits a highly featured band topology with a full band gap above E(F) and a hole-pocket-like Fermi surface. Here we show that controlled doping of the Ag/Cu(111) interface with Au allows one to observe a complete Lifshitz transition at 300 K; i.e., the hole pockets fill up, the band gap entirely shifts across E(F), and the Fermi surface becomes electron-pocket-like.

Synthesis of acyclovir and HBG analogues having nicotinonitrile and its 2-methyloxy 1,2,3-triazole.

Reaction of pyridin-2(1H)-one 1 with 4-bromobutylacetate (2), (2-acetoxyethoxy)methyl bromide (3) gave the corresponding nicotinonitrile O-acyclonucleosides, 4 and 5, respectively. Deacetylation of 4 and 5 gave the corresponding deprotected acyclonucleosides 6 and 7, respectively. Treatment of pyridin-2(1H)-one 1 with 1,3-dichloropropan-2-ol (8), epichlorohydrin (10) and allyl bromide (12) gave the corresponding nicotinonitrile O-acyclonucleosides 9, 11, and 13, respectively. Furthermore, reaction of pyridin-2(1H)-one 1 with the propargyl bromide (14) gave the corresponding 2-O-propargyl derivative 15, which was reacted via [3+2] cycloaddition with 4-azidobutyl acetate (16) and [(2-acetoxyethoxy)methyl]azide (17) to give the corresponding 1,2,3-triazole derivatives 18 and 19, respectively. The structures of the new synthesized compounds were characterized by using IR, (1)H, (13)C NMR spectra, and microanalysis. Selected members of these compounds were screened for antibacterial activity.

Synthesis, antitumor and antimicrobial activities of 4-(4-chlorophenyl)-3-cyano-2-(ß-O-glycosyloxy)-6-(thien-2-yl)-nicotinonitrile.

4-(4-Chlorophenyl)-3-cyano-6-(thien-2-yl)-1H-pyridin-2-one (2) was obtained by reaction of 2-acetyl thiophene with 4-chlorobenzaldehyde and ethyl cyanoacetate in presence of ammonium acetate or by the reaction of α,ß-unsaturated compound 1 with ethyl cyanoacetate in the presence of ammonium acetate. 4-(4-Chlorophenyl)-2-(2',3',4',6'-tetra-O-acetyl-ß-d-gluco/galactopyranosyloxy)-6-(thien-2-yl)nicotinonitrile (5a and 5b), riboside 11, xyloside 12 and lactoside 16 were prepared by the reaction of 2 with glycosyl/galactosyl/xylosyl/lactosyl bromide and peracetylated xylose/ribose under the conventional and microwave irradiation methods. The reaction has regioselectively gave the O-glycosides and not the N-glycosides. The glycosides 5a,b, riboside 11, xyloside 12 and lactoside 16 were deacetylated in the presence of Et(3)N/MeOH and few drops of water to give 7a,b, 13, 14 and 17. The structure of the new synthesized compounds was confirmed by using IR, (1)H, (13)C NMR spectra and microanalysis. Selected members of these compounds were screened for antitumor and antibacterial activity.