Inhibitory Effects of Plant Tannins on Ultraviolet Light-Induced Epidermal DNA Synthesis in Hairless Mice

Naturally occurring hydrolyzable (HT) and condensed (CT) tannins and their monomeric units were tested for their ability to inhibit the stimulation of DNA synthesis by UVB radiation. Hairless mice were irradiated with either single (200 mJ/cm²) or multiple (150 mJ/cm²) doses of UVB applied at 24 h intervals and epidermal DNA synthesis was measured at different times after the last of these treatments. The peak of DNA synthesis that is observed 48–56 h after a single UVB irradiation shifts to an earlier time of 16–24 h after multiple UVB treatments. Interestingly, the early inhibitory period of DNA synthesis observed 8 h after a single UVB treatment is not detected following multiple UVB treatments. Rather, DNA synthesis is stimulated six-fold 24 h after multiple UVB treatment, a response that is higher than the peak occurring 48–56 h after a single UVB irradiation. The disappearance of the early period of inhibition when the peak of DNA synthesis shifts to an earlier time may be linked to reactive oxygen species brought to the epidermis by infiltrating leukocytes, which, in turn, act as second messengers to stimulate growth signals in cells. Topical applications of HT or CT remarkably inhibit the DNA responses to single and multiple UVB treatments, an effect that is dependent on the dose and time of administration. Indeed, the peak stimulation of DNA synthesis is maximally inhibited when 17 mg of Tarapod tannic acid (TA), an HT, are applied topically 20 min before a single UVB treatment. The polymeric tannins inhibited DNA synthesis to a greater degree than equal doses of their monomeric units, gallic acid and catechin. These results suggest that various oligomeric HT and CT may be useful against tumor-promoting responses associated with the exposure of skin to physical carcinogens.     

Formation of a spiral-shaped inorganic-organic hybrid chain, [Cu(II)(2,2'-bipy)(H(2)O)(2)Al(OH)(6)Mo(6)O(18)](n)()(n)()(-): influence of intra- and interchain supramolecular interactions

A novel chainlike coordination polymer [Cu(II)(2,2'-bipy)(H(2)O)(2)Al(OH)(6)Mo(6)O(18)](n)()(n)()(-), formed from a heteropolyanion [Al(OH)(6)Mo(6)O(18)](3)(-) as a building unit and a copper(II) complex fragment, [Cu(II)(2,2'-bipy)(H(2)O)(2)](2+), as a linker, provides the first example of an extended structure based on an Anderson type of polyanion and a transition metal complex with organic ligand. The intra- and interchain O-H.O hydrogen-bonding interactions are seemingly responsible for the spiral shape of this chain. Crystal data: triclinic space group Ponemacr;, a = 11.2253(18) A, b = 14.5194(17) A, c = 15.2672(10) A, alpha = 112.191(8) degrees, beta = 106.693(9) degrees, gamma = 93.916(13) degrees, and Z = 2.     

Generation of millimeter wave Gaussian beams and their propagation in a dielectric waveguide

Linearly polarized fundamental mode Gaussian beams were generated and coupled to a hollow circular oversized dielectric waveguide by placing the waist of the beam at the guide entrance. The transmission properties of the waveguide were characterized as a function of frequency for a variety of coupling conditions. These conditions included changes in the input beam waist radius, angle of incidence, and displacement perpendicular and parallel to the guide axis. It has been found that: 1.) power transmission is maximized when the waist of the input beam is centered at the guide input, injected normally, and has a radius of 0.43 times the waveguide radius, 2.) power transmission decreases rapidly with increasing angle of incidence and the rate of that loss increases with frequency, 3.) the waveguide preserves the linear polarization of the input beam, 4.) power transmission in the fundamental waveguide mode is not greatly affected by moderate displacements in the input beam position, and 5.) upon exit from the waveguide the launched EH₁₁ mode propagates as a fundamental mode Gaussian beam in the quasi-far field. The results compare favorably to the transmission theory of Belland and Crenn and approximately to the near and far field mode pattern theory of Degnan.     

Earliness and tardiness single machine scheduling with proportional weights

This paper presents the first efficient method to solve an earliness-tardiness single machine n job scheduling model with idle times permitted. In this model the earliness and tardiness penalties are proportional to the processing times of the jobs. A two stage decomposition process builds the optimal job arrangement as a sequence of single and multijob blocks. The arrangement of the jobs within each multijob block is unspecified since it depends on the start time of this block. This process is followed by a procedure that drastically reduces the number of candidate optimal n job sequences. Finally an available optimal timing algorithm is recommended and implemented to select the best schedule among those sequences. The solution procedure tested on a PC on 400 examples for n=40 and 50 proves to be very fast.     

Perron Transforms

We generalize Zariski's Perron transforms to obtain a proof of local uniformization of an arbitrary singular variety of characteristic zero along a valuation of arbitrary rank. Furthermore, we resolve the centers of all the composite valuations as well as the prime ideals of infinite value.     

Solid-to-solid formation at the solid-liquid interface leading to a chiral coordination polymer from an achiral monomer

An achiral crystal of a simple mononuclear copper complex [Cu(II)(C(6)H(8)N(2))(2)SO(4)]·H(2)O (1), on dipping into an aqueous azide solution, transforms into a chiral crystal of a coordination polymer [Cu(II)(C(6)H(8)N(2))(N(3))(2)](n) (2) in a solid-liquid interface reaction demonstrating replacement of a sulfate anion by an azide anion from an aqueous solution.     

Spectroscopic Investigations for the Six New Synthesized Complexes of Fluoroquinolones and Quinolones Drugs With Nickel(Ⅱ) Metal Ion: Infrared and Electronic Spectroscopy

Quinolone has a broad spectrum of synthetic antibiotics with a strong therapeutic effect and quinolone is a term used for chemical treatments used to treat a powerful bacteria. Quinolones are divided into 4 generations according to the bacterial spectrum, the majority of quinolones used clinically belong to the sub fluoroquinolones group, which has a fluorine atom linked to the central ring system, usually on its carbon atom 6 or 7. Herein in this article, six new nickel(Ⅱ) complexes (Ⅰ-Ⅵ) have been synthesized in aqueous alkaline media at pH ranged 8-9, the chemical reactions take place between levofloxacin (HLEV), lomefloxacin (HLOM), nalidixic acid (HNLA), oxolonic acid (HOXO), pipemidic acid (HPIP), and pefloxacin mesylate (HPEF) with nickel(Ⅱ) nitrate hexahydrate. The microanalytical (percentage of carbon, hydrogen and nitrogen), molar conductance (Λ_m), Infrared (FTIR) spectra, electronic (UV-Vis) spectra, and effective magnetic moment instrumentals were used to identify the suggested structures and their surface morphology. According the analytical and spectroscopic analyses, the stoichiometry between nickel(Ⅱ) metal ion and drug ligands was found to be 1∶2 with general formula as [Ni(L)₂(H₂O)₂]·xH₂O (L=LEV (Ⅰ), LOM (Ⅱ), NAL (Ⅲ), OXO (Ⅳ), PIP (V), and PEF (Ⅵ); x=2 or 4). By the comparison between FTIR spectra of quinolone drugs and their complexes, it can be deduced that all the drug ligands act as a bidentate chelates through oxygen atoms of pyridine ring and carboxylate group. The electronic configuration of all synthesized nickel(Ⅱ) complexes were octahedral geometry which confirmed based on the values of magnetic susceptibility and the electronic transition bands.     

D-π-A-A-π-D prototype 2,2'-bipyridine dyads exhibiting large structure and environment-sensitive fluorescence: synthesis, photophysics, and computation

A series of 4,4'-π-conjugated-2,2'-bipyridine chromophores (MS 1-8) were synthesized, and their photophysical and thermal properties were investigated. The title "push-pull' chromophores", except MS 1, were integrated with both alkoxy and alkylamino donor functionalities that differ in their donation capabilities. The oligophenylenevinylene (OPV) chromophores MS 4-8 are associated with a π-extended backbone in which the position and the number of alkoxy donors were systematically varied. All of the studied systems possess a D-π-A-A-π-D dyad archetype in which the A-A is the central 2,2'-bipyridine acceptor core that is electronically attached with the donor termini through π-linkers. The fluorescence quantum yields of the synthesized chromophores are found to be sensitive to the molecular archetype and the solvent medium. Out of the eight fluorescent compounds reported in this article, the compound MS 5 exhibits fluorescence in the solid state also. The modulating effect of the nature, position, and number of donor functionalities on the optical properties of these classes of compounds has further been comprehended on the basis of DFT and TD-DFT computation in a solvent reaction field.     

Trithiaazafulvalene: a promising building block between tetrathiafulvalene and dithiadiazafulvalene

[reaction: see text] New electroactive building blocks, the trithiaazafulvalenes (TTAFs), were synthesized. These redox-active molecules, intermediate between tetrathiafulvalene (TTF) and dithiadiazafulvalene (DTDAF), show promising features for the elaboration of molecular materials.