Hofstadter butterfly of graphene with point defects

Cataloged from PDF version of article.We investigate the structure of Hofstadter's butterfly of graphene with point defects under a perpendicular magnetic field. We use a tight-binding method with interactions up to second-nearest neighbors. First of all, we present the Hofstadter butterfly spectrum of pure graphene, including all four valence orbitals with second-order hopping. To model defects, we perform calculations within an enlarged unit cell of seven carbon atoms and one defect atom. We find that impurity atoms with smaller hopping constants result in highly localized states which are decoupled from the rest of the system. The bands associated with these states form a nearly E = 0 eV line. On the other hand, impurity atoms with higher hopping constants are strongly coupled with the neighboring atoms. These states modify the Hofstadter butterfly around the minimum and maximum values of the energy by forming two self-similar bands decoupled from the original butterfly. We also show that the bands and gaps due to the impurity states are robust with respect to the second-order hopping

Hall conductance in graphene with point defects

Cataloged from PDF version of article.We investigate the Hall conductance of graphene with point defects within the Kubo formalism, which allows us to calculate the Hall conductance without constraining the Fermi energy to lie in a gap. For pure graphene, which we model using a tight-binding Hamiltonian, we recover both the usual and the anomalous integer quantum Hall effects depending on the proximity to the Dirac points. We investigate the effect of point defects on Hall conduction by considering a dilute but regular array of point defects incorporated into the graphene lattice. We extend our calculations to include next nearest neighbor hopping, which breaks the bipartite symmetry of the lattice. We find that impurity atoms which are weakly coupled to the rest of the lattice result in gradual disappearance of the high conductance value plateaus. For such impurities, especially for vacancies which are decoupled from the lattice, strong modification of the Hall conductance occurs near the E = 0 eV line, as impurity states are highly localized. In contrast, if the impurities are strongly coupled, they create additional Hall conductance plateaus at the extremum values of the spectrum, signifying separate impurity bands. Hall conductance values within the original spectrum are not strongly modified

The integer quantum Hall effect of a square lattice with an array of point defects

Cataloged from PDF version of article.The electronic properties of a square lattice under an applied perpendicular magnetic field in the presence of impurities or vacancies are investigated by the tight-binding method including up to second nearest neighbor interactions. These imperfections result in new gaps and bands in the Hofstadter butterfly even when the second order interactions break the bipartite symmetry. In addition, the whole spectrum of the Hall conduction is obtained by the Kubo formula for the corresponding cases. The results are in accordance with the Thouless-Kohmoto-Nightingale-den Nijs integers when the Fermi energy lies in an energy gap. We find that the states due to the vacancies or impurities with small hopping constants are highly localized and do not contribute to the Hall conduction. However, the impurities with high hopping constants result in new Hall plateaus with constant conduction of sigma(xy) = +/- e(2)/h, since high hopping constants increase the probability of an electron contributing to the conduction

The Relationship between Eating Behaviors of Children and Mothers, and Nutritional Status of Children

Introduction: Parents have a significant impact on child nutrition and the child's eating habits in long-term behavior. This study aims to examine the effects of mothers' attitudes on the eating behaviors of children and the determination of their nutritional status.Method: Children's eating habits and mothers' eating attitudes were examined in 417 children with face-to-face interviews using the Child Feeding Questionnaire (CFQ). The participants' anthropometric characteristics were determined, and body mass indexes (kg/m2) were calculated. AnthroPlus software was used to determine the children's BMI-for-age Z-scores. BeBiS nutrition information system was used to assess children's food intake.Results: The mothers' median BMI was above the overweight threshold. The lowest CFQ score was for perceived child weight, and the maximum score was for food restriction. Significant differences were found in mothers ages, mothers' BMIs, children's WAZ and BAZ scores, and BMIs, weight (p<0.001), perceived parent weight scores (p=0.04), and pressure to eat (p=0.04). Families should be conscious about nutrition for the protection and promotion of children's health

Bladder injury during infected tola hip arthroplasty prosthesis removal: Report of a case and review of the literature

The bladder is the most frequently injured organ during pelvic surgery. However, during hip surgery, this complication is extremely rare. We report a case of bladder injury during total hip arthroplasty prosthesis removal surgery. A 65-year-old male was admitted to our hospital with left hip pain and wound infection. On plain radiograms, acetabular protrusion was identified. We decided to remove protruzed acetabular cup and place spacer. During the operation, unexpectedly bladder injury occurred. The rupture was sutured intraoperatively. We left a catheter in the bladder after internal urethrotomy to drain the urine.Keywords: Arthroplasty, Bladder injury, Cystogram, Hip prosthesis removal, Infectio

How reproducible are surface areas calculated from the BET equation?

Porosity and surface area analysis play a prominent role in modern materials science. At the heart of this sits the Brunauer-Emmett-Teller (BET) theory, which has been a remarkably successful contribution to the field of materials science. The BET method was developed in the 1930s for open surfaces but is now the most widely used metric for the estimation of surface areas of micro- and mesoporous materials. Despite its widespread use, the calculation of BET surface areas causes a spread in reported areas, resulting in reproducibility problems in both academia and industry. To prove this, for this analysis, 18 already-measured raw adsorption isotherms were provided to sixty-one labs, who were asked to calculate the corresponding BET areas. This round-robin exercise resulted in a wide range of values. Here, the reproducibility of BET area determination from identical isotherms is demonstrated to be a largely ignored issue, raising critical concerns over the reliability of reported BET areas. To solve this major issue, a new computational approach to accurately and systematically determine the BET area of nanoporous materials is developed. The software, called "BET surface identification" (BETSI), expands on the well-known Rouquerol criteria and makes an unambiguous BET area assignment possible

Current trend in synthesis, Post-Synthetic modifications and biological applications of Nanometal-Organic frameworks (NMOFs)

Since the early reports of MOFs and their interesting properties, research involving these materials has grown wide in scope and applications. Various synthetic approaches have ensued in view of obtaining materials with optimised properties, the extensive scope of application spanning from energy, gas sorption, catalysis biological applications has meant exponentially evolved over the years. The far‐reaching synthetic and PSM approaches and porosity control possibilities have continued to serve as a motivation for research on these materials. With respect to the biological applications, MOFs have shown promise as good candidates in applications involving drug delivery, BioMOFs, sensing, imaging amongst others. Despite being a while away from successful entry into the market, observed results in sensing, drug delivery, and imaging put these materials on the spot light as candidates poised to usher in a revolution in biology. In this regard, this review article focuses current approaches in synthesis, post functionalization and biological applications of these materials with particular attention on drug delivery, imaging, sensing and BioMOFs

Parasitism of the Wheat Stinkbug, Aelia rostrata Boh. (Heteroptera: Pentatomidae) with the Entomopathogenic Nematode, Hexamermis sp (Nematoda: Mermithidae)

WOS: 000314559600008The aim of this study was to determine the rate of parasitism of wheat stinkbug (WSB), Aelia rostrata Boh. (Heteroptera: Pentatomidae) with Hexamermis sp. (Nematoda: Mermithidae) in 2010 and 2011. For this purpose, the adults of A rostrata were collected from overwintering areas in Ankara, Turkey. The samples were brought to laboratory and sexed. They were dissected to check for the presence or absence of mermithids. Thus, the rates of parasitism were calculated for females and males of A rostrata. Parasitism rates were 24.7 and 21.4% for females and 33.6 and 36.1% for males in 2010 and 2011, respectively. Parasitized A. rostrata contained an average of 2.6 +/- 0.72 nematode individuals. In a sample of 30 parasitized A. rostrata, 63.3% contained a single juvenile worm, 16.7% contained 2 and 20.0% contained 3 or more individuals. The mean body length of juvenile measured 7.6 +/- 0.24 cm for females and 3.0 +/- 0.15 cm for males. The results suggest that Hexamermis sp. is an important natural enemy of A rostrata in overwintering areas and could be potential a biological control agent for the pest management in the future

Reduction of spinal cord injury with pentobarbital and hypothermia in a rabbit model

WOS: 000179554600013PubMed ID: 12443752Objectives: to evaluate the effects of hypothermia and pentobarbital on spinal cord ischaemia induced in a rabbit model. Materials and Methods: thirty-two rabbits, allocated into four equal groups, had the infrarenal aorta clamped distal to the left renal artery and above the iliac bifurcation for 40 min. Groups 3 and 4 had infusion of 15 mg/kg of pentobarbital intravenously for 5 min, 15 min before the cross-clamping. Groups 2 and 4 had infusion of 20 ml of Ringer's lactate (LR) solution at 3degreesC for 3 min during aortic cross clamp into the isolated aortic segment. Group 1 was untreated and served as control. Postoperative functions of spinal cord were assessed. Results: paraplegia occurred in all rabbits in Group 1, in one in each of Groups 2 and 3, whereas no paraplegia was observed in Group 4. In addition 2 and 3 animals of Groups 2 and 3, respectively revealed varying degree of neurological disturbances, whereas all animals of Group 4 had normal function. This difference between Groups 2, 3, and 4 vs Group 1 was significant (p < 0.002). So was the difference between Groups 2 and 4 (p = 0.03), whereas the difference between Groups 3 and 4 was not significant. Conclusions: hypothermia and pentobarbital was more effective than hypothermia alone for prevention of spinal cord ischaemia in a rabbit model

Evaluation of phenolic compounds in Tilia rubra Subsp. caucasica by HPLC-UV and HPLC-UV-MS/MS

Profile of phenolic compounds of Tilia rubra subsp. caucasica was measured by high performance liquid chromatography coupled with ultraviolet and tandem mass spectroscopy. Three different extraction methods (methonolic, selective extraction, and acidic hydrolysis) were used to evaluate phenolic composition and antioxidant capacity in three different parts of T. rubra. The antioxidant activities of the species were investigated in terms of total phenolics and flavonoids, and cupric reducing antioxidant capacity and 1,1-diphenyl-2- picrylhydrazyl scavenging assays. Different phenolic compounds related to antioxidant activities of three different parts and three different extraction ways of T. rubra were determined by high performance liquid chromatography- ultraviolet and high performance liquid chromatography-mass spectroscopy. Gallic and protocatechuic acid were the main phenolic compounds in the all extracts and parts of Tilia rubra subsp. caucasica by high performance liquid chromatography-ultraviolet ranging from 356.20 to 159.83 and 1873.90 to 720.80 ?g phenolic compound/g dry sample, respectively. Epicatechin, luteolin, and rhamnazin were detected by high performance liquid chromatography-mass spectroscopy. © 2014 Copyright Taylor and Francis Group, LLC.Huseyin S¸ahin would like to thank TUB?TAK B?DEB for the financial support given to him. The authors would also like to thank Professor Salih Terziog?lu for identifying the tilia genus and Faculty of Pharmacology, Karadeniz Technical University for helping with the HPLC device