statement of problem: shear bond strength (sbs) of home and office bleached enamel will be compromised by immediate application of composite restoration. antioxidant agent may overcome this problem. objectives: this in vitro study assessed the effect of green tea extract on shear bond strength of resin composite to in-office and home-bleached enamel. materials and methods: in this experimental ...

Ribonucleotide reductases (RNRs) catalyze the conversion of ribonucleotides to deoxyribonucleotides in all living organisms. The catalytic cycle of E. coli RNR involves a long-range proton-coupled electron transfer (PCET) from a tyrosyl radical (Y122c) in subunit b2 to a cysteine (C439) in the active site of subunit a2, which subsequently initiates nucleotide reduction. This oxidation occurs ov...

Let n and q be given integers and X a finite set with n elements. The following theorem is proved for n > n0(q). The family of all q-element subsets of X can be partitioned into disjoint pairs (except possibly one if (n q ) is odd), so that |A1∩A2|+ |B1 ∩B2| ≤ q, |A1 ∩B2|+ |B1 ∩A2| ≤ q holds for any two such pairs {A1, B1} and {A2, B2}. This is a sharpening of a theorem in [2]. It is also shown...

(a) Prove that the sum and product of abstract symbols is well-defined. That is, if [a1, b1] = [a2, b2] and [c1, d1] = [c2, d2], prove that we have [a1, b1] · [c1, d1] = [a2, b2] · [c2, d2] and [a1, b1] + [c1, d1] = [a2, b2] + [c2, d2] . (b) One can check that Q satisfies all of the axioms of Z except for the Well-Ordering Axiom (please don’t check this), with additive identity [0, 1] ∈ Q and m...

We use the following convention: A, B, C, A1, B1, C1, A2, B2, C2 are points of E2 T, l1, m1, n1 are real numbers, and X, Y , Z are subsets of E2 T. Let us consider X, Y . We introduce X is parallel to Y as a synonym of X misses Y . Let us consider X, Y , Z. We say that X, Y , Z are concurrent if and only if: (Def. 1) X is parallel to Y and Y is parallel to Z and Z is parallel to X or there exis...

We give a synthetic proof of Dao’s generalization of the Simson line theorem. In [3], Dao Thanh Oai published without proof a remarkable generalization of the Simson line theorem. Theorem 1 (Dao). Let ABC be a triangle with its orthocenter H , let P be an arbitrary point on the circumcircle. Let l be a line through the circumcenter and AP , BP , CP meet l at A1, B1, C1, respectively. Denote A2,...

The 1:1 Cu(II) complexes of bleomycin (BLM) A2, BLM B2, epi-BLM B2, iso-BLM B2, depyruvamide-BLM A2, deglyco-BLM B2 and the structurally related peptides (P-5m, P-3A and P-3) have been comprehensively investigated by ESR and electrochemical methods. ESR spectra for Cu(II) complexes of BLM A2, epi-BLM B2, depyruvamide-BLM A2 and P-3 revealed the axially symmetric g-anisotropies. In contrast, ESR...

Traditional medicine "Jamu" is becoming very popular used by the community as an alternative treatment that can minimize side effects. However, it profitable for manufacturers who are not responsible herbal products adding medicinal chemicals (BKO) to traditional products. The samples in this study were of coded A1, A2; B1, B2; C1, C2; D1, D2; E1, E2; and F1, F2, which analyzed qualitatively qu...