Tuning a Circular p-n Junction in Graphene from Quantum Confinement to Optical Guiding

The motion of massless Dirac-electrons in graphene mimics the propagation of photons. This makes it possible to control the charge-carriers with components based on geometrical-optics and has led to proposals for an all-graphene electron-optics platform. An open question arising from the possibility of reducing the component-size to the nanometer-scale is how to access and understand the transition from optical-transport to quantum-confinement. Here we report on the realization of a circular p-n junction that can be continuously tuned from the nanometer-scale, where quantum effects are dominant, to the micrometer scale where optical-guiding takes over. We find that in the nanometer-scale junction electrons are trapped in states that resemble atomic-collapse at a supercritical charge. As the junction-size increases, the transition to optical-guiding is signaled by the emergence of whispering-gallery modes and Fabry-Perot interference. The creation of tunable junctions that straddle the crossover between quantum-confinement and optical-guiding, paves the way to novel design-architectures for controlling electronic transport.Comment: 16 pages, 4 figure

Artificial propagation and Culture of Rutilus frisii kutum of Autumn form for restocking

The Kutum, Rutilus frisii kutum, is one of the most important bony fishes in Iranian coastal of Caspian Sea. Its harvest range is between 9000-10000 tons in a year, nearly 60% of the income of Bony fish fishery produced by kutum fishery. The stock of this species reduced drastically in 1982 and the catch slumped to the less than 250 tons in a year. Kutum spawning grounds deterioration, illegal catch, and lack of restocking program were the main cause of the decline. This Spices in nature comprised by two distinct form, autumn and spring form. It is worth to be mentioned, by the effect of Caspian Sea Bony fishes Research Center s experts in 1983, artificial spawning and releasing the fries to the sea were commenced and the catch steadily improved. But all activities concerning restocking of kutum concentrated in spring form, as at present about 260 million its fries are released into sea for restocking by Iranian Fisheries Organization, but for above reasons and lack of restocking program, the populations of autumn form gravely shrinked and neared to be extinct. Therefore, to enhance the biodiversity and boost fishers livelihood of kutum in Caspian Sea this project implemented by cooperation of Iranian Fisheries Organization (IFRO) and Caspian Environment Program (CEP) in Aquaculture Institute (Inland Waters). In this project, brooders caught from Anzali lagoon and maintained in two different condition, include of floating cages in Anzali lagoon and earthen ponds in Sefidrud Fisheries Research Station. The results showed that there weren’t significant differences between two maintenance statuses in maturation period and other reproductive characteristics of brooders. The ratio of male to female was 1 to 1.4. Minimum and maximum weight measured 1450 to 3100 g (with average of 1850 g) in female and 670 to 1900 g (with average of 1165 g) in male, respectively. The first natural spawning of brooders occurred in the end of January in temperature of 8 till 10 °C in concrete ponds. Also, some of maintained brooders in earthen ponds spawned in February. The average number of absolute, function and relative fecundity determined 88565 16809, 73805 14008 and 48670 12056, respectively. For artificial spawning, male and female brooders injected by pituitary gland with dose of 2-3 and 4-5 mg/kg body weight, respectively. Approximately, 10 and 8 present of female were over-ripe and immature in March (artificial spawning time), respectively. More than 59 % of injected female brooders induced to spawning in first stage after 10-12 hours and 13 % of them in twice stage and 7-8 hours after first stage. And also, 27.6% of females didn’t positive response to injection. Dry method used for eggs fecundity and incubation period lasted 7- 10 days in 14-16 °C. In totally, eggs fertilization were more than 95% and the average of eggs fertilization percent in throughout of period measured more than 92.7 6 %. Eyed eggs appearance occurred 3 days after fecundity and its mean was 92.7 15.1%. Larvae after yolk sac absorption feed with dry milk for 4-5 days and then introduced into fertilized earthen ponds (500 m2 and equipped to aerators) in intensive condition and fed with micro pellet food for 3-4 month. In finally, more than 1.8 million fries of 1-2 g and some more than 5 g produced and released into Anzali lagoon to its restocking for first time. It is expected that continuing of restocking process of autumn form kutum by Iranian Fisheries Organization eventuate to population increasing of this form in Caspian Sea in future

Identification and characterization of pathogenic viruses in aquatic animal using advanced techniques in order to develop rapid diagnostic kit (shrimp viral disease kit as well as TSV, HPV and MBV )

Shrimp production increasing rapidly in the world and in2013 the production reaches 4.2 MT. In Iran the shrimp production is under development and estimated in 1393, 20 thousand tons produced. In this regards the important subject is health and disease in shrimp farm. The white spot syndrome virus for second time appears in chabahar and damage many farms. Because the aquaculture activity expand in the world in national, regional and international scale, many emerge disease are endanger. In this regard the viral disease is very important and not only decrease the production but also has a side effect in business and national economy. For control and prevention the viral disease, the accurate methods such as PCR kit were developed. In this project the PCR methods with sensitivity, specificity and efficacy was designed and used for detection viral disease. Many viruses have several serotypes and in different area maybe new serotype induce the disease. For this reason, the specific kit will be design. Three viruses consist of MBV, TSV and IHHNV are very pathogenic in shrimp farm and need the specific PCR kit for detection them. In this project the MBV virus was identified and designs a new primer with Oligo software and the primer amplified a part of DNA with 185 bp in the gel. The specificity and sensitivity of primer were checked by IQ2000 Kit and the primer used for detection unknown samples

Study on viral nervouse necrosis (isolation, characterisation and pathogenesis) in golden grey mullet in the Caspian Sea and study of pathogenecity and possibility of transmission to the other fish species (Sturgeon fishes, Rutilus frisii kutum and reared Rainbow trout and Carp)

Study on Viral Nervouse necrosis (isolation, characterisation and pathogenesis) in Golden grey mullet in the Caspian Sea and study of pathogenecity and possibility of transmission to the other fish species (Sturgeon fishes, Rutilus frisii kutum and reared Rainbow trout and Carp) Viral Nervous Necrosis (VNN) is a worldwide disease affecting several species of cultured marine fish. For the past two decades, betanodavirus infections that cause Viral Nervous Necrosis (VNN) have emerged as major constraints on the culture and sea ranching of marine fish in almost all parts of the world. More than forty species mainly of marine origin have been so far affected and this number is likely to rise in future following the introduction of new species and the increase of aquaculture trade. Unknown acute mortality occurred in wild golden grey mullet Lisa auratus and Liza saliens in Iranian waters of Caspian Sea in recent years. In order to isolation and confirmation of causative agents of golden grey mullet mortality in the Caspian Sea, a complementary research investigation project was designed in 2005 and approved immediately in Iranian Fisheries Research Organization (IFRO). Many diagnostic aspects such as Virology (Cell culture and Elctereone Microscopy), Hemathology, Bacteriology, Histopathology, Molecular biology (NestedRT-PCR), Heavy metals measuerment and Serology (IFAT and IHC) were employed in mentioned multidiciplinary project. About 322 moribund fish samples which revealed skin darkening, erratic swimming behavior such as spiral and belly-up at rest and high distention of swimming bladder. Suspected samples were collected from coastal capture sites in iranian north proviences in 2006 till 2009. Targets tissue such as brain and eye were removed in strile condition and then kept in -80oC frezzer for cell culture and Nested-RT-PCR. Other tissue samples from liver, kidney, intestine, stomach, gill, skin and muscle, gall bladder and gonads were taken and fixed in 10% buffer formalin and same parts fixed in glutaraldehyde 3% for histopathology, IHC and EM respectively. Cytopathic effect (CPE) was observed in those cell cultures just six days after inoculation with the dilutions of the tested 312 homogenate supernatants. CPE in monolayers of cells cultured (SSN-1 cell line) was characterised by thin or rounded, refractile, granular cells with vacuoles. Nine samples were positive in virology assay. Nested- RT-PCR was done on suspected tissue samples and supernatant of CPE positive samples and 21 tissue samples and all CPE positive samples were positive. IFAT was selected as a confirmatory method for identifying viral strains replicating on cell cultures and carried out with rabbit anti-betanodavirus serum on suspected tissue samples and some smears of CPE positive samples. Some bright points approved betanodavirus antigen and confirmed cell culture and Nested-RT-PCR findings. In fixed tissue samples widespread and massive vacuolation were observed in brain, spinal cord, retina and optical nerve. In order to confirmation of diagnostic findings , IHC was done with monoclonal antibody antibetanodavirus and some red-brown points were observed. Theses findings revealed expected viral antigens and confirmed previous results. Moreover, virus particles with 25-30 nm in diameter were visualized in infected brain and retina using positive staining in TEM. Also pathogenicity test was employed to confirm the obtained results. So Guppy fish Poecilia reticulata and sturgeon fry were used instead of the experimental host due to ease of handling and susceptibility. After 15 days post infection, guppy bathed in VNN-infected tissue culture with 104 TCID50 showed clinical signs similar to naturally infected Golden grey mullet, and the mortality rate reached up to 100% in 75 dpi. When target organs were examined by cell culture isolation, serology, and histopathology, all revealed the presence of virus in the Guppy. Suspected supernatant injected to sturgeon fry through intravitreous injection and widespread vacuolation were observed in brain and spinal cord buy IHC and Real time PCR were negative. In conclusion, with attntion to obtained results in this investigation such as ecological factors, clinical signs, histopathological, virological and bacteriological results, molecular analysis, (IHC, IFAT, PCR), TEM demonstration, serological and hematological findings, it could be confirmed that VNNV was the main causative agent for disease outbreak in Golden grey mullet in Southern coastline of Caspian Sea

Prevalence of gingivitis among school attendees in Qazvin, Iran

Objective: The purpose of this study was to determine the gingival status in six to nine years old (6-9 years).Methods: A Total (n= 792) patients comprised 396 girls and 396 boys between 6-9 years were selected from school in Qazvin. Names,ages, sex, addresses and gingival status of each patient were recorded in separate questionnaires. Intra oral examinations were performed with mirror, probe and good light.Results: Among total n=792 patients, the female were 396(50%) and male were 396(50%). The prevalence of gingivitis was 97% (in 6-7 years), 98.1% (7-8 years), 98.5% (in 8-9 years) and 97.9% in all groups.Conclusion: In present study the frequency of gingivitis was found to be higher. According to the high prevalence of gingivitis the most prevalent areas of plaque and gingivitis identified in this study should be taken in consideration during oral hygiene instructions, which should be given to children, parents, and teacher

Different species of basil need different ammonium to nitrate ratio in hydroponics' system

Basil is a very important medicinal plant and culinary spice, and is marketed fresh, dried or frozen. In crop nutrition, nitrogen is essential for plant growth and as a macro-element, is part of the proteins’ structure and participates in the metabolic processes involved in the synthesis and energy transfer. It has been shown that a balance between ammonium and nitrate favors plant growth and that the degree of benefit varies among crops. This study was conducted to evaluate the growth of two varieties of basil in function of four nutrient solutions containing different NH4+/NO3- ratios. Results showed that different variety response differently to nutrient solution. Although the highest yield in both varieties (sweet and purple) was obtained when fed by nutrient solution without ammonium but their response on quality indices were different due to nitrate ammonium ratio in nutrient solutions. The highest total phenol content of sweet and purple basil was 92 and 100 mg gallic acid equivalent per gram of dry weight respectively, while the highest antioxidant capacity was obtained in purple variety grown in nutrient solution 2 (NH4+:1/NO3:4) and the lowest value were related to sweet variety with the same nutrient solution. Moderate content of total nitrogen can be suitable for sweet variety while for purple variety nutrient solution with low amount of ammonium can be more suitable

Različni biotipi bazilike potrebujejo v razmerah hidroponskega gojenja različna razmerja nitrata in amonija

Basil is a very important medicinal plant and culinary spice, and is marketed fresh, dried or frozen. In crop nutrition, nitrogen is essential for plant growth and as a macro-element, is part of the proteins’ structure and participates in the metabolic processes involved in the synthesis and energy transfer. It has been shown that a balance between ammonium and nitrate favors plant growth and that the degree of benefit varies among crops. This study was conducted to evaluate the growth of two varieties of basil in function of four nutrient solutions containing different NH4+/NO3- ratios. Results showed that different variety response differently to nutrient solution. Although the highest yield in both varieties (sweet and purple) was obtained when fed by nutrient solution without ammonium but their response on quality indices were different due to nitrate ammonium ratio in nutrient solutions. The highest total phenol content of sweet and purple basil was 92 and 100 mg gallic acid equivalent per gram of dry weight respectively, while the highest antioxidant capacity was obtained in purple variety grown in nutrient solution 2 (NH4+:1/NO3:4) and the lowest value were related to sweet variety with the same nutrient solution. Moderate content of total nitrogen can be suitable for sweet variety while for purple variety nutrient solution with low amount of ammonium can be more suitable

Comparing the three color pounehh tooth paste with the conventional one in preventing the formation of the microbial plaque

"nBackground and Aim: Plaque control has always been important in preventive dentistry. Various methods and materials have been introduced for this purpose. Recently a three-colored tooth paste has been introduced which claims to prevent plaque formation. The aim of this study was to compare three-colored pouneh tooth paste containing triclosan with the conventional one in preventing plaque formation. "nMaterials and Methods: This was a randomized double blind cross over clinical trial which was carried out on 40 dental students of Tehran azad university in 2005. Before beginning the trial, the index of plaque was evaluated, registered and reduced to null. The subjects were randomly divided into two groups, the case group (three color tooth paste) and the control group (conventional tooth paste). The participants were asked to apply the specified tooth paste with an oral B Advantage Artica toothbrush for two weeks. After two weeks, the amount of plaque was re-registered and again reduced to null. The type of tooth paste was changed among two groups and the plaque was registered for the third time at the end of two weeks. Then the patients and assessors were not aware of the type of tooth paste in the tubes (double blind). McNamar and ManWhitney test were used. "nResults: From the 40 subjects, 4 cases were omitted due to the different reasons. The amount of initial plaque index was 88.3 12.1 which was reduced to 78.2 16.9 in the control and 74.1 19.3 in the case group. The difference between primary plaque and secondary plaque (after applying tooth paste) was significant in both case and control groups, however there was not any significant difference between two groups. "nConclusion: Based on the results of this study, there was not any significant difference between conventional and three-colored tooth paste in reducing the plaque index

Extending the application of a magnetic PEG three-part drug release device on a graphene substrate for the removal of Gram-positive and Gram-negative bacteria and cancerous and pathologic cells

M Ramezani Farani,1 P Khadive Parsi,1 Gh Riazi,2 M Shafiee Ardestani,3 H Saligeh Rad4,5 1School of Chemical Engineering, University College of Engineering, University of Tehran, Tehran 4563-11155, Iran; 2Institute of Biophysics and Biochemistry, University of Tehran, Tehran 1417614411, Iran; 3Department of Radiopharmacy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran; 4Quantitative Medical Imaging Systems Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran; 5Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran Objective: In this study, novel graphene oxide (GO)-based nanocomposites are presented. In fact, we have tried to replace the carboxyl groups on the surface of GO with amine groups to allow the biocompatible poly(ethylene glycol) bis(carboxymethyl) ether (average Mn 600) polymer to bond through an amide bond. Materials and methods: The synthesis was conducted accurately according to final characterization experiments (Raman, X-ray diffraction [XRD], atomic force microscopy [AFM], X-ray photoelectron spectroscopy [XPS], thermogravimetric analysis [TGA], etc). The antimicrobial property of this nanocomposite was examined in Escherichia coli (ATCC 25922) as Gram-negative and Staphylococcus aureus (ATCC 25923) as Gram-positive bacterial species. Besides, curcumin (CUR) was added to the produced nanocomposite both as a promising anticancer drug and an antioxidant, the toxicity of which was then assessed on cellular-based HepG2 and pC12. Results: An intense increase in toxicity was detected by MTT assay. Conclusion: It can mainly be concluded that the nanocomposite synthesized in this study is capable of delivering drugs with antibacterial properties. Keywords: graphene oxide, magnetic nanocomposite, drug delivery, antimicrobial, curcumi