Modification of anatase TiO2_2(001) surface electronic structure by Au impurity

We have used density functional theory calculations based on the projector augmented wave method to investigate the electronic structure of Au-incorporated anatase TiO$_2$(001) surface. Due to the coordination with several level oxygens, Au atoms can be encapsulated inside TiO$_2$ slab. Au is adsorbed over the surface Ti--O bond, so called the bridge site on anatase TiO$_2$(001)--1$\times$1 surface. However, for 0.25 ML coverage, Au atoms energetically prefer to stay at 0.64 {\AA} above the midpoint of the two surface oxygens which is significantly closer to the surface layer. When implanted inside the slab for full coverage, Au forms parallel metallic wires inside TiO$_2$ lattice where interlayer distances increase due to local segregation. Au brings half-filled impurity states into the band gap leading to metallization, in addition to other filled surface and impurity bands within the gap. These Au-driven Fermi-level-pinning gap states are close to, or even in some cases inside, the conduction band of the host slab. On the other hand, if Au is substituted for the surface Ti atom, Fermi level falls lower in the gap closer to the valence band top.Comment: 10 pages, 4 figure

Range separated hybrid density functional study of organic dye sensitizers on anatase TiO2_2 nanowires

The adsorption of organic molecules coumarin and the donor-$\pi$-acceptor type tetrahydroquinoline (C2-1) on anatase (101) and (001) nanowires have been investigated using screened Coulomb hybrid density functional theory calculations. While coumarin forms single bond with the nanowire surface, C2-1 additionally exhibits bidentate mode giving rise to much stronger adsorption energies. Nonlinear solvation effects on the binding characteristics of the dye chromophores on the nanowire facets have also been examined. These two dye sensitizers show different electronic charge distributions for the highest occupied and the lowest unoccupied molecular states. We studied the electronic structures in terms of the positions of the band edges and adsorbate related band gap states and their effect on the absorption spectra of the dye-nanowire combined systems. These findings were interpreted and discussed from the view point of better light harvesting and charge separation as well as in relation to more efficient charge carrier injection into the semiconductor nanowire.Comment: 8 pages, 4 figures, and 1 tabl

Antioxidant Enzyme Activities and Abiotic Stress Tolerance Relationship in Vegetable Crops

Climatic changes can cause serious reductions in yield and crop quality. Under the threat of climatic changes, one of the precautions to cope is selection and development of resistant vegetable genotypes to abiotic stresses. Several physiological and biochemical reactions and different tolerance levels can occur according to plant species. When plants are subjected to environmental stresses such as salinity, drought, temperature extremes, herbicide treatment and mineral deficiency, the balance between the production of reactive oxygen species (ROS) and the quenching activity of antioxidants is upset, often resulting in oxidative damage. Since activated oxygen species can disrupt normal metabolism through oxidative damage to lipids, protein and nucleic acids, plants possess a number of antioxidant enzymes that protect them from these cytotoxic effects. To control the level of ROS and to protect cells under stress conditions, plant tissues contain several enzymes for scavenging ROS. The high levels of antioxidative enzyme activities were determined in the tolerant genotypes of tomatoes, eggplant, peppers, cucumbers, melons, squash, beans, okra, etc. to several abiotic stress factors. Both the whole plant and in vitro callus culture experiments gave similar results. Antioxidant enzymes can be useful for screening to determine the tolerant and sensitive plant genotypes against abiotic stresses

DFT study of noble metal impurities of TiO2(110)

Cataloged from PDF version of article.Atomic and electronic structures of TiO2(110) surface with possible adsorptional, substitutional and interstitial Au or Pt elemental impurities at full and one-sixth monolayer concentrations were investigated by density functional theory calculations using the projector augmented wave approach within the plane wave method. Relative thermodynamic stabilities of such phases have been discussed by means of their surface free energies. Our results suggest that tunable photocatalytic activity can be achieved on Pt atom admixed rutile (110) surface at low coverages

Indução de divisão nuclear simétrica e estruturas multinucleadas em micrósporos de berinjela (Solanum melongena L.) cultivados in vitro

Uma modificação de um protocolo utilizado para induzir embriogênese a partir de micrósporos de tabaco foi testada em berinjela (Solanum melongena L.). Em tabaco, micrósporos uninucleados são submetidos a um tratamento de estresse em meio "B" contendo manitol a 33ºC por seis dias. Os micrósporos são então transferidos para um meio AT3 contendo maltose para as fases posteriores de desenvolvimento. Neste estudo, micrósporos uninucleados e binucleados tardios do cultivar de berinjela Bambino foram pré-cultivados em meio "B" e, posteriormente, incubados a 4ºC, 25ºC e 33ºC por dois dias. Após os pré-tratamentos, as culturas de micrósporos foram transferidas para o meio AT3 contendo maltose 0,25 M e mantidas a 25ºC no escuro. A presença de divisão simétrica e estruturas multinucleadas foram verificadas com coloração DAPI do núcleo após uma e duas semanas. Foram observadas divisões simétricas dos núcleos e estruturas multinucleadas somente em micrósporos uninucleados, pré-tratados a 33ºC por dois dias. A frequência de estruturas multinucleadas foi de 19,4% sob essas condições. Nós demonstramos que a berinjela responde ao protocolo modificado de tabaco para produção de divisões simétricas e estruturas multinucleadas. Esses resultados podem ser utilizados como base para uma completa adaptação do sistema de tabaco em berinjela.A modification of a protocol used to induce tobacco microspore embryogenesis was tested in eggplant (Solanum melongena L.). In tobacco, uninucleate microspores are subjected to stress treatment by culturing in mannitol containing "B" medium at 33ºC for six days. The microspores are then transferred to maltose containing AT3 medium for further development. In the experiment presented here late uninucleate and bi-nucleate microspores of the eggplant cultivar Bambino were pre-cultured in B medium and then incubated at +4ºC, 25ºC and 33ºC, respectively, for two days. After the pre-treatments, microspore cultures were transferred to AT3 medium containing 0.25 M maltose and maintained at 25ºC in the dark. Presence of symmetrical division and multinucleate structures was checked with DAPI staining of the nucleus after one and two weeks. Symmetrical division of the nucleus and multinucleate structures were observed only in uni-nucleate microspores pre-treated at 33ºC for two days. The frequency of multinucleate structures was 19.4% under these conditions. We demonstrated that eggplant is responsive to the modified tobacco protocol in the production of symmetrically division and multinucleate structures. These results may be used as a basis for adaptation fully of the tobacco system in eggplant

The investigation of electronic, mechanical and lattice dynamical properties of PdCoX (X=Si and Ge) half-Heusler metallics in , and structural phases: an ab initio study

WOS: 000406494900001PdCoX (X=Si and Ge) alloys which are XYZ type half-Heusler alloys and also have face centred cubic MgAgAs-type structure which conforms to space group, have been investigated in different atomic arrangements which are called , and phases, using local spin density approximation in the density functional theory as implemented in VASP (Vienna Ab Initio Simulation Package) software. Both of the alloys are considered in ferromagnetic order. After the investigation of stable structural phase for these alloys, their full structural, electronic, magnetic, mechanical, and dynamical properties have been examined in this structural phase. The calculated electronic band structure and the total electronic density of states of our alloys indicated metallic behaviour. The estimated elastic constants show that these are stable and show anisotropic behaviour mechanically in and phases. Also, the calculated phonon dispersion curves show that PdCoX (X=Si and Ge) alloys are stable dynamically in the same structural phases.Ahi Evran University Research Project UnitAhi Evran University [PYO-KMY.4001.15.001]This work was supported by the Ahi Evran University Research Project Unit [project number PYO-KMY.4001.15.001]

The efficacy of intra-articular PRP, ozone and ozone+PRP injections in patients with osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis and some joints are effected more than others. The prevalence of OA increases with age and it represents the major problem for functional impairment in older patients. Non-surgical treatment with oral drugs is not suitable for many patients suffering from gastric disorders, high blood pressure or different heart diseases. Intra-articular injections are a promising solution in these cases. This study was performed to compare the efficacy and safety of ozone injections, PRP (platelet rich plasma) injections and combined ozone plus PRP injections in patients with symptomatic knee OA. 120 patients were diagnosed of OA according to the criteria of the American College of Rheumatology and included into this study. Patients were randomly divided into three equal groups (40 patients each group). We include patients whose VAS score was 5 or above. Patients with inflammatory, endocrine and metabolic disturbances, and patients who had meniscectomy within the past 10 years, extra articular surgery within the last year, arthrocentesis in last 6 months or any drug given intra-articular were not included. We did not include either patients with misalignment. Patients in the first group were treated with intra-articular injections of ozone/oxygen gas mixture 2 times/week, at 10 µg/mL concentration and a volume of 5 mL for a total of 12 injections. Patients in the second group were treated only with PRP injections once a week for a total of 3 times. Patients in the third group were treated with intra-articular injections of Ozone+PRP (10 µg/ml concentration, 5 ml volume) once a week for a total of 3 times. The pain levels of patients were measured with Visual Analog Scale (VAS). Side effects were collected using an open list record. All the groups improved their baseline VAS in a significant way, although the group with the best results was group 3 with the combination of ozone and PRP in the same injection. We are planning further studies including systemic ozone in order to improve more the pain in our patients