623 research outputs found

    Cancer registry in Iran: A brief overview

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    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

    The Effects of Excited States and Energetic Traps on Charge Transport in Disordered Organic Small Molecule Semiconductors.

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    PhDCharge transport is the one the most fundamental concepts in organic semiconductors. The key quantity that characterises this transport behaviour is carrier mobility. The ability to transport carriers in a fast and unimpeded nature in organic devices such as Organic Photovoltaics (OPV) or Organic Light Emitting Diodes (OLED) is a key parameter for building more efficient devices. Significant steps have so far been taken to understand and model this phenomenon, however there are still many questions that need to be answered. One such fundamental question is the role of excited states on the charge transport properties of organic materials which historically has been ignored. This thesis aims to investigate the transport properties of two of the most widely used organic materials, N,N′-bis-[(1-naphthyl)-N,N′-diphenyl]-1,1′-biphenyl)-4,4′-diamine (NPB) and are N,N’-diphenyl-N,N’-bis 3-methylphenyl-1,1’-biphenyl-4,4’-diamine (TPD). We demonstrate how excitons are generated in a single organic layer OLED devices and how traditionally hole transport materials are capable of fast long range electron transport. We provide a comprehensive analysis of the charge transport properties of both materials with respect to the Gaussian Disorder Model (GDM) and demonstrate how both types of carriers can easily be transported in these materials. We then investigate the effects of exciton generation on the transport properties of the materials and propose some numerical modeling to analyse the effects of such excited states and the distribution of energetic traps in our system. We show that the swing of carrier mobility in either direction depends on the interplay and dominance of each mechanism (triplet/carrier interaction and trap filling). We also investigate the effects of 5 removing excited states from our device by deliberately introducing impurities via doping of a phosphorescent molecule to alter their concentration. Finally we propose some future direction that one can take to model charge transport behaviour in disordered organics based on the experimental work discussed in thesis

    Operator Gauge Symmetry in QED

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    In this paper, operator gauge transformation, first introduced by Kobe, is applied to Maxwell's equations and continuity equation in QED. The gauge invariance is satisfied after quantization of electromagnetic fields. Inherent nonlinearity in Maxwell's equations is obtained as a direct result due to the nonlinearity of the operator gauge transformations. The operator gauge invariant Maxwell's equations and corresponding charge conservation are obtained by defining the generalized derivatives of the first and second kinds. Conservation laws for the real and virtual charges are obtained too. The additional terms in the field strength tensor are interpreted as electric and magnetic polarization of the vacuum

    Black hole solutions to Einstein-Bel-Robinson gravity

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    By employing a combination of perturbative analytic methods, we study the physical properties of a static-spherically symmetric black hole in the framework of the recently proposed Einstien-Bel-Robinson version of gravity. We show that interestingly the theory propagates a transverse and massive graviton on a maximally symmetric background with positive energy. There is also a single ghost-free branch that returns to the Einstein case when \beta\to 0. Then, we obtain the conserved charges of the theory to study the thermodynamics of the black hole solutions. We get the thermodynamical quantities and show that the solutions undergo a first-order phase transition with associated Van der Waals behavior. We analyze the specific heat, determining that the black holes are thermodynamically stable over large regions of parametric space.Comment: 16 pages, 5 figure

    DNA vaccination with a plasmid encoding LACK-TSA fusion against Leishmania major infection in BALB/c mice

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    Vaccination would be the most important strategy for the prevention and elimination of leishmaniasis. The aim of the present study was to compare the immune responses induced following DNA vaccination with LACK (Leishmania analogue of the receptor kinase C), TSA (Thiol-specific-antioxidant) genes alone or LACK-TSA fusion against cutaneous leishmaniasis (CL). Cellular and humoral immune responses were evaluated before and after challenge with Leishmania major (L. major). In addition, the mean lesion size was also measured from 3th week post-infection. All immunized mice showed a partial immunity characterized by higher interferon (IFN)-gamma and Immunoglobulin G (IgG2a) levels compared to control groups (p< 0.05). IFN-gamma/Interleukin (IL)-4 and IgG2a/IgG1 ratios demonstrated the highest IFN-gamma and IgG2a levels in the group receiving LACK-TSA fusion. Mean lesion sizes reduced significantly in all immunized mice compared with control groups at 7th week post-infection (p< 0.05). In addition, there was a significant reduction in mean lesion size of LACK-TSA and TSA groups than LACK group after challenge (p< 0.05). In the present study, DNA immunization promoted Th1 immune response and confirmed the previous observations on immunogenicity of LACK and TSA antigens against CL. Furthermore, this study demonstrated that a bivalent vaccine can induce stronger immune responses and protection against infectious challenge with L. major

    SUSTAINABLE LAND USE EVALUATION BASED ON PRESERVATIVE APPROACH

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    Determining the manner of land-use and the spatial structure of cities on the one hand, and the economic value of each piece of land on the other hand, land-use planning is always considered as the main part of urban planning. In this regard, emphasizing the efficient use of land, the sustainable development approach has presented a new perspective on urban planning and consequently on its most important pillar, i.e. land-use planning. In order to evaluate urban land-use, it has been attempted in this paper to select the most significant indicators affecting urban land-use and matching sustainable development indicators. Due to the significance of preserving ancient monuments and the surroundings as one of the main pillars of achieving sustainability, in this research, sustainability indicators have been selected emphasizing the preservation of ancient monuments and historical observance of the city of Susa as one of the historical cities of Iran. It has also been attempted to integrate these criteria with other land-use sustainability indicators. For this purpose, Kernel Density Estimation (KDE) and the AHP model have been used for providing maps displaying spatial density and combining layers as well as providing final maps respectively. Moreover, the rating of sustainability will be studied in different districts of the city of Shush so as to evaluate the status of land sustainability in different parts of the city. The results of the study show that different neighborhoods of Shush do not have the same sustainability in land-use such that neighborhoods located in the eastern half of the city, i.e. the new neighborhoods, have a higher sustainability than those of the western half. It seems that the allocation of a high percentage of these areas to arid lands and historical areas is one of the main reasons for their sustainability
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