Cosmological coincidence problem in interacting dark energy models

An interacting dark energy model with interaction term $Q= \lambda_m H\rho_m+\lambda_dH\rho_d$ is considered. By studying the model near the transition time, in which the system crosses the w=-1 phantom-divide-line, the conditions needed to overcome the coincidence problem is investigated. The phantom model, as a candidate for dark energy, is considered and for two specific examples, the quadratic and exponential phantom potentials, it is shown that it is possible the system crosses the w=-1 line, meanwhile the coincidence problem is alleviated, the two facts that have root in observations.Comment: 15 pages, LaTeX. Some minor explanations are added. To be published in Phys. Rev.

Cancer registry in Iran: A brief overview

Cancer registry is an important tool for any successful cancer control program. The first formal cancer related data from Iran were published in 1956. In 1969, observations documenting a high incidence of esophageal cancer in the Caspian Littoral, urged researchers to set up the first population-based cancer registry in this region. This cancer registry was established jointly by University of Tehran and the International Agency for Research on Cancer (IARC). In 1976, another cancer registry started its activities in Fars Province. In 1984, the Parliament passed a bill mandating the report of all tissues "diagnosed or suspected as cancer tissue" to the Ministry of Health. While only 18% of all estimated cancer cases were reported in first reports, this rate increased to 81% in 2005 In 1998, Tehran Population-Based Cancer Registry started to collect data from cases of cancer referred to the treatment and diagnostic facilities throughout the Tehran metropolis. Digestive Disease Research Center, Tehran University of Medical Sciences, established four new population-based cancer registries in Northern Iran and another in Kerman Province in the south. These five provinces have a total population of about 9.5 million, and constitute about 16% of the total population of Iran. While the pathology-based cancer registration is in place, we hope that the addition of the population-based cancer registries, and establishment of new registries in poorly-covered areas, will improve cancer reporting in the country

Cosmological entropy and generalized second law of thermodynamics in F(R,G)F(R,G) theory of gravity

We consider a spatially flat Friedmann-Lemaitre-Robertson-Walker space time and investigate the second law and the generalized second law of thermodynamics for apparent horizon in generalized modified Gauss Bonnet theory of gravity (whose action contains a general function of Gauss Bonnet invariant and the Ricci scalar: $F(R,G)$). By assuming that the apparent horizon is in thermal equilibrium with the matter inside it, conditions which must be satisfied by $F(R,G)$ are derived and elucidated through two examples: a quasi-de Sitter space-time and a universe with power law expansion.Comment: 10 pages, minor changes, typos corrected, accepted for publication in Europhysics Letter

Transition from quintessence to phantom phase in quintom model

Assuming the Hubble parameter is a continuous and differentiable function of comoving time, we investigate necessary conditions for quintessence to phantom phase transition in quintom model. For power-law and exponential potential examples, we study the behavior of dynamical dark energy fields and Hubble parameter near the transition time, and show that the phantom-divide-line w=-1 is crossed in these models.Comment: LaTeX, 19 pages, four figures, some minor changes in Introduction, two figures added and the references updated, accepted for publication in Phys. Rev.

Modelling the Effects of Competing Anions on Fluoride Removal by Functionalized Polyacrylonitrile Coated with Iron Oxide Nanoparticles

Fe2O3 nano particles supported on functionalized poly-acrylonitrile was prepared. PAN-oxime-nano Fe2O3 was characterized by XRD, FTIR andTEMand used for fluoride adsorption. The adsorption capacity increased with increasing initial fluoride concentration and reaction time. Fluoride-removal performance of PAN-oxime-nano Fe2O3 was also tested in the presence of various competing anions usually found in drinking water. Competitive sorption between fluoride and competing anions showed a minimum preference for chloride counterions. Carbonate was the greatest competitor for fluoride removal followed by phosphate and sulphate. Counterion presence decreased fluoride adsorption capacity in order of CO32−> PO43−> SO42−> Cl−. The presence of anions at various concentrations decreased fluoride adsorption capacity on PAN-oxime-nano Fe2O3 by 1.22 to 6.51 mg g–1. Effects of each two anions exist simultaneously in aqueous solution on fluoride adsorption was investigated using Tukey’s test (called also a pairwise comparison). Tukey’s HSD results indicate that the differences between various pairs of anions are significant (P < 0.05), except for chloride–sulphate (P = 0.08). In the design of PAN-oxime-nano Fe2O3 for environmental applications, the strong influence of the counter ions must be considered.KEYWORDS Fluoride, PAN-oxime- nano Fe2O3, counterion, adsorption

Declining incidence of esophageal cancer in the Turkmen Plain, eastern part of the Caspian Littoral of Iran: A retrospective cancer surveillance

Background: Previous studies have shown that upper gastrointestinal cancers are the most common cancers in Caspian Littoral, and rate of esophageal cancer (EC) in Iranian Turkmens residing in the Eastern part of littoral are among the highest in the world. Our aim was to reassess the rate 30 years later and following socioeconomic changes in the region. Methods: A comprehensive retrospective search was undertaken to find all new cancer cases during the 1996-2000 period. Diagnosis of cancer was based on histopathological reports in 68.2, clinical and/or radiological evidence in 29.7 and death certificate only (DCO) in 2.1 of the cases. Results: A total of 5143 new cancer cases were registered of whom 3063 (59.6) were males. The median (IQR) age was 60 (44-69) years. Age-standardized rates (ASR) for all cancers in males and females were 134.7 and 104.5 per 100,000, respectively. Based on ASR, the top five common cancers in males (excluding skin cancer) were cancers of esophagus (43.4), stomach (27.8), colorectal (10.7), bladder (7.8) and oral cavity (6.3), while in females cancer of esophagus (36.3) was followed by cancers of breast (15.7), stomach (8.3) colorectal (6.6) and cervix (3.6). Conclusion: We conclude that EC incidence rate has decreased to less than half the rate reported 30 years ago, while the incidence rates of colorectal and breast cancers have increased significantly. © 2006 International Society for Preventive Oncology. Published by Elsevier Ltd. All rights reserved

Cancer incidence in Golestan province: Report of an ongoing population-based cancer registry in Iran between 2004 and 2008

Background: Golestan Province, at the western end of the Asian esophageal cancer (EC) belt in northeastern Iran, was reported to have one of the highest worldwide rates of EC in the 1970s. We have previously shown a declining incidence of EC in Golestan during the last decades. This study reports additional new results from the Golestan Population-based Cancer Registry (GPCR). Methods: The GPCR collected data from newly diagnosed (incident) cancer cases from all 68 public and private diagnostic and therapeutic centers in Golestan Province. CanReg-4 software was used for data entry and analysis based on the guidelines of the International Agency for Research on Cancer (IARC). Age-standardized incidence rates (ASR) of cancers were calculated using the 2000 world standard population. Results: From 2004 through 2008, 9007 new cancer cases were reported to the GPCR. The mean (SD) age was 55.5 (18.6) years, and 54 were diagnosed in men. The ASRs of all cancers were 175.3 and 141.1 per 100,000 person-years for males and females, respectively. Cancers of the stomach (ASR:30.7), esophagus (24.3), and lung (15.4) were the most common cancers in males. In females, breast cancer (ASR:26.9) was followed by malignancies of the esophagus (19.1) and stomach (12.4). The diagnosis of cancer was based on histopatho- logical reports in 71 and on death certificate only in 9 ofcases. Conclusions: The EC incidence rate continues to decline in Golestan, while the incidence rates of stomach, colorectal, and breast cancers continue to increase

The incidence of prostate cancer in Iran: Results of a population-based cancer registry

Background: Little is known about the epidemiology of prostate cancer in Iranian men. We carried out an active prostate cancer surveillance program in five provinces of Iran. Methods: Data used in this study were obtained from population-based cancer registries between 1996 and 2000. Results: The age-standardized incidence rate of prostate carcinoma in the five provinces was 5.1 per 100,000 person-years. No significant difference was seen in the age-standardized incidence rate of prostate cancer within the provinces studied. The mean±SD age of patients with prostate cancer was 67±13.5 years. Conclusion: The incidence of prostate cancer in Iran is very low as compared to the Western countries. This can partly be explained by lack of nationwide screening program, younger age structure and quality of cancer registration system in Iran

Preparation of palladated porous nitrogen-doped carbon using halloysite as porogen: disclosing its utility as a hydrogenation catalyst

In this article, halloysite nanoclay (Hal) was used as porogen for the synthesis of nitrogen doped porous carbon material with high specific surface area and pore volume. To this purpose, polymerization of melamine and terephthalaldehyde (MT) was performed in the presence of amine-functionalized carbon coated Hal (Hal@Glu-2N) that was prepared from hydrothermal treatment of Hal and glucose. Then, the prepared nanocomposite was palladated and carbonized to afford Pd@Hal@C. To further improve the textural properties of the nanocomposite, and introduce more pores in its structure, Hal nanotubes were etched. The characterization of the resulting compound, Pd@C, and comparing it with Pd@Hal@C, showed that etching of Hal significantly increased the specific surface area and pore volume in Pd@C. Pd@C was successfully used as a heterogeneous catalyst for promoting hydrogenation of nitroarens in aqueous media using hydrogen with atmospheric pressure as a reducing agent. The comparison of the structural features and catalytic activity of the catalyst with some control catalysts, including, Pd@Hal, Pd@Hal@Glu, Pd@Hal@Glu-MT and Pd@Hal@C confirmed that nitrogen groups in C could improve the Pd anchoring and suppress its leaching, while etching of Hal and introduction of more pores could enhance the catalytic activity through facilitating the mass transfer

wd=−1w_d=-1 in interacting quintessence model

A model consisting of quintessence scalar field interacting with cold dark matter is considered. Conditions required to reach $w_d=-1$ are discussed. It is shown that depending on the potential considered for the quintessence, reaching the phantom divide line puts some constraints on the interaction between dark energy and dark matter. This also may determine the ratio of dark matter to dark energy density at $w_d=-1$.Comment: 10 pages, references updated, some notes added, minor changes applied, accepted for publication in Eur. Phys. J.