Hematologia e sinais clínicos de Piaractus mesopotamicus infectados experimentalmente com Aeromonas hydrophila = Hematology and clinical signs of Piaractus mesopotamicus experimentally infected with Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

Flávio Ruas Moraes

2009-01-01

Full Text Available Este ensaio teve como objetivo avaliar as respostas hematológicas e a ocorrência de sinais clínico-patológicos de Piaractus mesopotamicus infectados experimentalmente por Aeromonas hydrophila. Foram utilizados 324 pacus, P. mesopotamicus, com peso de 102,84 ±27,1 g, distribuídos em 27 caixas de 300 L de capacidade, sendo 14 peixes por caixa. Os peixes foram mantidos nas caixas durante um mês, recebendo dieta balanceada, período em que se evitou qualquer tipo de manejo estressante. Passado esse período, foram infectadoscom 6 x 106 UFC de A. hydrophila, injetada via intraperitoneal. As coletas e análises de sangue foram realizadas 24h antes da infecção experimental e 24h após a infecção. Os resultados permitem concluir que a infecção por A. hydrophila em P. mesopotamicus écaracterizada por escurecimento da derme e sinais clínicos-patológicos relacionados à hemorragia, anemia normocítica-hipocrômica, redução nos níveis de proteínas, globulinasplasmáticas e eosinófilos, leucopenia, linfopenia, trombocitopenia, neutrofilia e monocitose. The purpose of this study was to evaluate the hematological response and clinical sign of Piaractus mesopotamicus infected byAeromonas hydrophila. Were used 324 pacus, P. mesopotamicus weighing 102.84 ± 27.1 g distributed in 27 water tanks with 300 L of capacity, 14 fish per tank. The fish were kept in the water tanks during one month, receiving appropriate diet. In this period was avoidedstressing management. After this period, the fish were infected with 6 × 108 cfu of A. hydrophila fish-1, injected intraperitoneally. The blood collection was carried 24h before experimental infection and 24h after its. The A. hydrophila infection in P. mesopotamicus ischaracterized by dark skin and clinical signs related to hemorrhage, hypochromic normocytic anemia, decrease on plasmatic proteins and globulins levels, leucopenia, lymphopenia, thrombocytopenia, eosinophilia, neutrophilia and monocytosis.

Role of pH in oxidase variability of Aeromonas hydrophila.

OpenAIRE

Hunt, L K; Overman, T L; Otero, R B

1981-01-01

Some strains of Aeromonas hydrophila may be oxidase negative or only weakly oxidase positive by the Kovacs method taken from the surface of a differential medium, such as MacConkey agar. Six strains of A. hydrophila, two oxidase variable, one oxidase constant, and three weakly oxidase positive on MacConkey agar, were studied to determine the cause of oxidase variability. The bacteriostatic dyes in MacConkey agar were considered possible inhibitors of the oxidase reaction. The concentration of...

Chromosomal flhB1 gene of the alphaproteobacterium Azospirillum brasilense Sp245 is essential for correct assembly of both constitutive polar flagellum and inducible lateral flagella.

Science.gov (United States)

Filip'echeva, Yulia; Shelud'ko, Andrei; Prilipov, Alexei; Telesheva, Elizaveta; Mokeev, Dmitry; Burov, Andrei; Petrova, Lilia; Katsy, Elena

2018-03-01

Azospirillum brasilense has the ability of swimming and swarming motility owing to the work of a constitutive polar flagellum and inducible lateral flagella, respectively. The interplay between these flagellar systems is poorly understood. One of the key elements of the flagellar export apparatus is the protein FlhB. Two predicted flhB genes are present in the genome of A. brasilense Sp245 (accession nos. HE577327-HE577333). Experimental evidence obtained here indicates that the chromosomal coding sequence (CDS) AZOBR_150177 (flhB1) of Sp245 is essential for the production of both types of flagella. In an flhB1:: Omegon-Km mutant, Sp245.1063, defects in polar and lateral flagellar assembly and motility were complemented by expressing the wild-type flhB1 gene from plasmid pRK415. It was found that Sp245.1063 lost the capacity for slight but statistically significant decrease in mean cell length in response to transfer from solid to liquid media, and vice versa; in the complemented mutant, this capacity was restored. It was also shown that after the acquisition of the pRK415-harbored downstream CDS AZOBR_150176, cells of Sp245 and Sp245.1063 ceased to elongate on solid media. These initial data suggest that the AZOBR_150176-encoded putative multisensory hybrid sensor histidine kinase-response regulator, in concert with FlhB1, plays a role in morphological response of azospirilla to changes in the hardness of a milieu.

Light microscopy morphological characteristics of the sperm flagellum may be related to axonemal abnormalities.

Science.gov (United States)

Mitchell, V; Sigala, J; Ballot, C; Jumeau, F; Barbotin, A L; Duhamel, A; Rives, N; Rigot, J M; Escalier, D; Peers, M C

2015-03-01

Although electron microscopy provides a detailed analysis of ultrastructural abnormalities, this technique is not available in all laboratories. We sought to determine whether certain characteristics of the flagellum as assessed by light microscopy were related to axonemal abnormalities. Forty-one patients with an absence of outer dynein arms (type I), a lack of a central complex (type III) and an absence of peripheral doublets (type IV) were studied. Sperm morphology was scored according to David's modified classification. Flagella with an irregular thickness were classified as being of normal length, short or broken. There were correlations between missing outer dynein arms and abnormal, short or coiled flagellum. Type III patients showed the highest flagellar defects (a short (P = 0.0027) or an absent flagellum (P = 0.011)). Just over 68% of the irregular flagella were short in Type III patients, whereas this value was only 34.5% in type I and 26.4% in type IV (P = 0.002). There was a negative correlation between misassembly and spermatozoa of irregular flagella (r = -0.79; P = 0.019). It is concluded that light microscopy analysis of flagellum abnormalities may help provide a correct diagnosis, identify sperm abnormalities with fertility potentials and outcomes in assisted reproduction technologies and assess the genetic risk. © 2014 Blackwell Verlag GmbH.

[Real-time PCR in rapid diagnosis of Aeromonas hydrophila necrotizing soft tissue infections].

Science.gov (United States)

Kohayagawa, Yoshitaka; Izumi, Yoko; Ushita, Misuzu; Niinou, Norio; Koshizaki, Masayuki; Yamamori, Yuji; Kaneko, Sakae; Fukushima, Hiroshi

2009-11-01

We report a case of rapidly progressive necrotizing soft tissue infection and sepsis followed by a patient's death. We suspected Vibrio vulnificus infection because the patient's underlying disease was cirrhosis and the course extremely rapid. No microbe had been detected at death. We extracted DNA from a blood culture bottle. SYBR green I real-time PCR was conducted but could not detect V. vulnificus vvh in the DNA sample. Aeromonas hydrophila was cultured and identified in blood and necrotized tissue samples. Real-time PCR was conducted to detect A. hydrophila ahh1, AHCYTOEN and aerA in the DNA sample extracted from the blood culture bottle and an isolated necrotized tissue strain, but only ahh1 was positive. High-mortality in necrotizing soft tissue infections makes it is crucial to quickly detect V. vulnificus and A. hydrophila. We found real-time PCR for vvh, ahh1, AHCYTOEN, and aerA useful in detecting V. vulnificus and A. hydrophila in necrotizing soft tissue infections.

Roles of phagocytosis activating protein (PAP) in Aeromonas hydrophila infected Cyprinus carpio.

Science.gov (United States)

Wonglapsuwan, Monwadee; Kongmee, Pataraporn; Suanyuk, Naraid; Chotigeat, Wilaiwan

2016-06-01

Cyprinus carpio (koi) is one of the most popular ornamental fish. A major problem for C. carpio farming is bacterial infections especially by Aeromonas hydrophila. Previously studies had shown that the Phagocytosis Activating Protein (PAP) gene was involved in the innate immune response of animals. Therefore, we attempted to identify a role for the PAP gene in the immunology of C. carpio. The expression of the PAP was found in C. carpio whole blood and increased when the fish were stimulated by inactivated A. hydrophila. In addition, PAP-phMGFP DNA was injected as an immunostimulant. The survival rate and the phagocytic index were significantly increased in the A. hydrophila infected fish that received the PAP-phMGFP DNA immunostimulant. A chitosan-PAP-phMGFP nanoparticle was then developed and feeded into fish which infected with A. hydrophila. These fish had a significantly lower mortality rate than the control. Therefore, this research confirmed a key role for PAP in protection fish from bacterial infection and the chitosan-PAP-phMGFP nanoparticle could be a good prototype for fish immunostimulant in the future. Copyright © 2016 Elsevier Ltd. All rights reserved.

Parasites in motion: flagellum-driven cell motility in African trypanosomes

Science.gov (United States)

Hill, Kent L.

2011-01-01

SUMMARY Motility of the sleeping sickness parasite, Trypanosoma brucei, impacts disease transmission and pathogenesis. Trypanosome motility is driven by a flagellum that harbors a canonical 9 + 2 axoneme, together with trypanosome-specific elaborations. Trypanosome flagellum biology and motility have been the object of intense research over the last two years. These studies have led to the discovery of a novel form of motility, termed social motility, and provided revision of long-standing models for cell propulsion. Recent work has also uncovered novel structural features and motor proteins associated with the flagellar apparatus and has identified candidate signaling molecules that are predicted to regulate flagellar motility. Together with earlier inventories of flagellar proteins from proteomic and genomic studies, the stage is now set to move forward with functional studies to elucidate molecular mechanisms and investigate parasite motility in the context of host-parasite interactions. PMID:20591724

The LBP Gene and Its Association with Resistance to Aeromonas hydrophila in Tilapia

Directory of Open Access Journals (Sweden)

Gui Hong Fu

2014-12-01

Full Text Available Resistance to pathogens is important for the sustainability and profitability of food fish production. In immune-related genes, the lipopolysaccharide-binding protein (LBP gene is an important mediator of the inflammatory reaction. We analyzed the cDNA and genomic structure of the LBP gene in tilapia. The full-length cDNA (1901 bp of the gene contained a 1416 bp open reading frame, encoding 471 amino acid residues. Its genomic sequence was 5577 bp, comprising 15 exons and 14 introns. Under normal conditions, the gene was constitutively expressed in all examined tissues. The highest expression was detected in intestine and kidney. We examined the responses of the gene to challenges with two bacterial pathogens Streptcoccus agalactiae and Aeromonas hydrophila. The gene was significantly upregulated in kidney and spleen post-infection with S. agalactiae and A. hydrophila, respectively. However, the expression profiles of the gene after the challenge with the two pathogens were different. Furthermore, we identified three SNPs in the gene. There were significant associations (p < 0.05 of two of the three SNPs with the resistance to A. hydrophila, but not with the resistance to S. agalactiae or growth performance. These results suggest that the LBP gene is involved in the acute-phase immunologic response to the bacterial infections, and the responses to the two bacterial pathogens are different. The two SNPs associated with the resistance to A. hydrophila may be useful in the selection of tilapia resistant to A. hydrophila.

Aquatically acquired Aeromonas hydrophila wound infection A ...

African Journals Online (AJOL)

The occurrence of Aeromonas hydrophila wound infections in healthy hosts after water-associated injury is being reported more frequently. This paper reports our experience with 3 such cases and outlines the importance of recognising the association between a water-related injury and, this organism.

Turning off flagellum rotation requires the pleiotropic gene pleD: pleA, pleC, and pleD define two morphogenic pathways in Caulobacter crescentus.

OpenAIRE

Sommer, J M; Newton, A

1989-01-01

We have identified mutations in three pleiotropic genes, pleA, pleC, and pleD, that are required for differentiation in Caulobacter crescentus. pleA and pleC mutants were isolated in an extensive screen for strains defective in both motility and adsorption of polar bacteriophage phi CbK; using temperature-sensitive alleles, we determined the time at which the two genes act. pleA was required for a short period at 0.7 of the swarmer cell cycle for flagellum biosynthesis, whereas pleC was requi...

The Influences of Bacillus subtilis on the Virulence of Aeromonas hydrophila and Expression of luxS Gene of Both Bacteria Under Co-cultivation.

Science.gov (United States)

Ren, Yuwei; Li, Sisi; Wu, Zhixin; Zhou, Chengchong; Zhang, Ding; Chen, Xiaoxuan

2017-06-01

The aim of this study was to explore the influence of Bacillus subtilis CH9 on Aeromonas hydrophila SC2005. The transcription level of virulence genes of A. hydrophila SC2005 and its hemolysin activity as well as its cytotoxicity were analyzed when B. subtilis CH9 and A. hydrophila SC2005 were co-cultured. The results indicated that the transcription levels of four virulence genes of A. hydrophila, including aer, ahyB, hcp, and emp, decreased when A. hydrophila was cultured with B. subtilis CH9. Furthermore, the extracellular products of A. hydrophila showed attenuated hemolysin activity as well as cytotoxicity when A. hydrophila was cultured with B. subtilis CH9. Finally, the transcriptional levels of luxS genes of B. subtilis CH9 and A. hydrophila SC2005 were determined when these two species were co-cultured. RT-qPCR results suggested that the transcription level of A. hydrophila was down-regulated significantly. On the contrary, the transcription level of B. subtilis CH9 was up-regulated significantly. These results suggested that the probiotic role of B. subtilis CH9 is related to the inhibition of growth and virulence of A. hydrophila SC2005, and quorum sensing may be involved.

Detection and analysis of hemolysin genes in Aeromonas hydrophila isolated from Gouramy (Osphronemus gouramy) by polymerase chain reaction (PCR)

Science.gov (United States)

Rozi; Rahayu, K.; Daruti, D. N.

2018-04-01

The goal of this study was to detect of Aeromonas hydrophila carrying the hlyA gene in guramy by PCR assay. A total of 5 A. hydrophila strains were isolated from gouramy with different location and furthermore genotypic of all A. hydrophila strains havedetected by PCR assay for 16S rRNA gene. The primers used in the PCR targeted a 592-bp fragment of the hlyA gene coding for the hemolysin gene. Particularly hlyA genes are responsible for haemolysin toxins production in this genus. After gel electrophoresis, the amplicons from representative strains of the A. hydrophila were purified using extraction kit and were subjected to the DNA sequencing analysis. The results showed that: (i) the 592bp amplicon of the hlyA gene was detected in 5/6 of the A. hydrophila; (ii) the nucleotide blast results of hemolysin gene sequences of the strains of A. hydrophila revealed a high homology of 90-97 % with published sequences, and;(iii) the protein blast showed 95-98 % homology when compared to the published sequences. The PCR clearly identified the haemolysin-producing strains of A. hydrophila by detection in hlyA genes and may have application as a rapid species-specific virulence test.

Characterization of Aeromonas hydrophila wound pathotypes by comparative genomic and functional analyses of virulence genes.

Science.gov (United States)

Grim, Christopher J; Kozlova, Elena V; Sha, Jian; Fitts, Eric C; van Lier, Christina J; Kirtley, Michelle L; Joseph, Sandeep J; Read, Timothy D; Burd, Eileen M; Tall, Ben D; Joseph, Sam W; Horneman, Amy J; Chopra, Ashok K; Shak, Joshua R

2013-04-23

Aeromonas hydrophila has increasingly been implicated as a virulent and antibiotic-resistant etiologic agent in various human diseases. In a previously published case report, we described a subject with a polymicrobial wound infection that included a persistent and aggressive strain of A. hydrophila (E1), as well as a more antibiotic-resistant strain of A. hydrophila (E2). To better understand the differences between pathogenic and environmental strains of A. hydrophila, we conducted comparative genomic and functional analyses of virulence-associated genes of these two wound isolates (E1 and E2), the environmental type strain A. hydrophila ATCC 7966(T), and four other isolates belonging to A. aquariorum, A. veronii, A. salmonicida, and A. caviae. Full-genome sequencing of strains E1 and E2 revealed extensive differences between the two and strain ATCC 7966(T). The more persistent wound infection strain, E1, harbored coding sequences for a cytotoxic enterotoxin (Act), a type 3 secretion system (T3SS), flagella, hemolysins, and a homolog of exotoxin A found in Pseudomonas aeruginosa. Corresponding phenotypic analyses with A. hydrophila ATCC 7966(T) and SSU as reference strains demonstrated the functionality of these virulence genes, with strain E1 displaying enhanced swimming and swarming motility, lateral flagella on electron microscopy, the presence of T3SS effector AexU, and enhanced lethality in a mouse model of Aeromonas infection. By combining sequence-based analysis and functional assays, we characterized an A. hydrophila pathotype, exemplified by strain E1, that exhibited increased virulence in a mouse model of infection, likely because of encapsulation, enhanced motility, toxin secretion, and cellular toxicity. Aeromonas hydrophila is a common aquatic bacterium that has increasingly been implicated in serious human infections. While many determinants of virulence have been identified in Aeromonas, rapid identification of pathogenic versus nonpathogenic

Antimicrobial susceptibility pattern of Aeromonas hydrophila among ...

African Journals Online (AJOL)

A total of one hundred and twenty eight (128) stool samples were collected from patients attending Ahmadu Bello University Teaching Hospital Zaria and Aminu Kano Teaching Hospital Kano, and screened for the presence of Aeromonas hydrophila infection. Out of the one hundred and twenty eight samples analyzed 4 ...

Characterization of Aeromonas hydrophila Wound Pathotypes by Comparative Genomic and Functional Analyses of Virulence Genes

Science.gov (United States)

Grim, Christopher J.; Kozlova, Elena V.; Sha, Jian; Fitts, Eric C.; van Lier, Christina J.; Kirtley, Michelle L.; Joseph, Sandeep J.; Read, Timothy D.; Burd, Eileen M.; Tall, Ben D.; Joseph, Sam W.; Horneman, Amy J.; Chopra, Ashok K.; Shak, Joshua R.

2013-01-01

ABSTRACT Aeromonas hydrophila has increasingly been implicated as a virulent and antibiotic-resistant etiologic agent in various human diseases. In a previously published case report, we described a subject with a polymicrobial wound infection that included a persistent and aggressive strain of A. hydrophila (E1), as well as a more antibiotic-resistant strain of A. hydrophila (E2). To better understand the differences between pathogenic and environmental strains of A. hydrophila, we conducted comparative genomic and functional analyses of virulence-associated genes of these two wound isolates (E1 and E2), the environmental type strain A. hydrophila ATCC 7966T, and four other isolates belonging to A. aquariorum, A. veronii, A. salmonicida, and A. caviae. Full-genome sequencing of strains E1 and E2 revealed extensive differences between the two and strain ATCC 7966T. The more persistent wound infection strain, E1, harbored coding sequences for a cytotoxic enterotoxin (Act), a type 3 secretion system (T3SS), flagella, hemolysins, and a homolog of exotoxin A found in Pseudomonas aeruginosa. Corresponding phenotypic analyses with A. hydrophila ATCC 7966T and SSU as reference strains demonstrated the functionality of these virulence genes, with strain E1 displaying enhanced swimming and swarming motility, lateral flagella on electron microscopy, the presence of T3SS effector AexU, and enhanced lethality in a mouse model of Aeromonas infection. By combining sequence-based analysis and functional assays, we characterized an A. hydrophila pathotype, exemplified by strain E1, that exhibited increased virulence in a mouse model of infection, likely because of encapsulation, enhanced motility, toxin secretion, and cellular toxicity. PMID:23611906

Establishment of infection models in zebrafish larvae (Danio rerio to study the pathogenesis of Aeromonas hydrophila.

Directory of Open Access Journals (Sweden)

Paolo Roberto Saraceni

2016-08-01

Full Text Available Aeromonas hydrophila is a Gram-negative opportunistic pathogen of fish and terrestrial animals. In humans, A. hydrophila mainly causes gastroenteritis, septicaemia and tissue infections. The mechanisms of infection, the main virulence factors and the host immune response triggered by A. hydrophila have been studied in detail using murine models and adult fish. However, the great limitation of studying adult animals is that the animal must be sacrificed and its tissues/organs extracted, which prevents the study of the infectious processes in the whole living animal.Zebrafish larvae are being used for the analysis of several infectious diseases, but their use for studying the pathogenesis of A. hydrophila has never been explored. The great advantage of zebrafish larvae is their transparency during the first week after fertilization, which allows detailed descriptions of the infectious processes using in vivo imaging techniques such as differential interferential contrast (DIC and fluorescence microscopy. Moreover, the availability of fluorescent pathogens and transgenic reporter zebrafish lines expressing fluorescent immune cells, immune marker genes or cytokines/chemokines allows the host-pathogen interactions to be characterized.The present study explores the suitability of zebrafish larvae to study the pathogenesis of A. hydrophila and the interaction mechanisms between the bacterium and the innate immune responses through an infection model using different routes for infection. We used an early-embryo infection model at 3 days post-fertilization (dpf through the microinjection of A. hydrophila into the duct of Cuvier, caudal vein, notochord or muscle and two bath infection models using 4 dpf healthy and injured larvae. The latter resembled the natural conditions under which A. hydrophila produces infectious diseases in animals. We compared the cellular processes after infection in each anatomical site by confocal fluorescence imaging and

Detection of Aeromonas hydrophila Using Fiber Optic Microchannel Sensor

Directory of Open Access Journals (Sweden)

Samla Gauri

2017-01-01

Full Text Available This research focuses on the detection of Aeromonas hydrophila using fiber optic microchannel biosensor. Microchannel was fabricated by photolithography method. The fiber optic was chosen as signal transmitting medium and light absorption characteristic of different microorganisms was investigated for possible detection. Experimental results showed that Aeromonas hydrophila can be detected at the region of UV-Vis spectra between 352 nm and 354 nm which was comparable to measurement provided by UV spectrophotometer and also theoretical calculation by Beer-Lambert Absorption Law. The entire detection can be done in less than 10 minutes using a total volume of 3 μL only. This result promises good potential of this fiber optic microchannel sensor as a reliable, portable, and disposable sensor.

Classification of a hypervirulent Aeromonas hydrophila pathotype responsible for epidemic outbreaks in warm-water fishes

Science.gov (United States)

Lineages of hypervirulent Aeromonas hydrophila (vAh) are the cause of persistent outbreaks of motile Aeromonas septicemia in warm-water fishes worldwide. Over the last decade, this virulent lineage of A. hydrophila has resulted in annual losses of millions of tons of farmed carp and catfish in the P...

Effectiveness of ambon banana stem juice as immunostimulatory against Aeromonas hydrophila infections in catfish Clarias gariepinus

Directory of Open Access Journals (Sweden)

Qorie Astria

2017-07-01

Full Text Available ABSTRACT Outbreaks of infectious diseases due to Aeromonas hydrophila in catfish can cause high death rates (80–100%. Fish disease control can be done using phytopharmaceutical to prevent or treat diseases of fish. One of the phytopharmaceutical that known to prevent the fish diseases is ambon banana stem Musa cavendishii var. dwarf Paxton. This study was conducted to test the effectiveness of catfish immersion using banana stem juice as an immunostimulant against bacterial infections A. hydrophila. The observed parameters were a total performance of production, hematological test, and water quality. Immersion of catfish seeds with stem juice was performed at a concentration of 5 mL/L, 13 mL/L, and 21 mL/L for 30 minutes. Each treatment consisted of three replications. A  total of 15 fishes were immersed in 1.5 L water. At day-9 after immersion, fish was infected by A. hydrophila bacteria at a dose of 104 cfu/mL. The results showed that fish treated with banana stem juice at a concentration of 13 mL/L had the survival rate of 53.33±6.67% which is higher than positive control (33.33±6.67%. Based on hematology observations on the 3rd day post-challenge test (H12 with A. hydrophila, total erythrocytes, hemoglobin, total leukocytes, phagocytic activity, differential leukocyte, and lysozyme activity was highest in treatment13 mL/L. Lower feed conversion ratio (1.08±0.04 were also obtained in treatment 13 mL/L. Thus Immersion of seeds in stem juice can boost the immune system against infections A. hydrophila. Keywords: Aeromonas hydrophila, ambon banana stem juice, soaking, catfish, immune system  ABSTRAK Wabah penyakit akibat infeksi Aeromonas hydrophila pada ikan lele dapat menyebabkan tingkat kematian yang tinggi (80–100%. Penanggulangan penyakit ikan dapat dilakukan menggunakan fitofarmaka untuk mencegah ataupun mengobati penyakit ikan. Salah satu fitofarmaka yang dapat digunakan dalam upaya pencegahan penyakit ikan adalah batang

Aeromonas hydrophila-associated skin lesions and septicaemia in a Nile crocodile (Crocodylus niloticus : clinical communication

Directory of Open Access Journals (Sweden)

H. Turutoglu

2005-06-01

Full Text Available Aeromonas hydrophila is one of the most common bacteria associated with the aquatic environment. There are , however, limited data on A. hydrophila infection in crocodilians. The aim of this report is to describe a case of skin lesions and septicaemia associated with A. hydrophila in a Nile crocodile (Crocodylus niloticus. A captive male crocodile in the Zoological Park of Antalya (Turkey was found dead without showing signs of any disease. Gross examination showed brown or red-spotted skin lesions of varying size. These lesions were mostly scattered over the abdomen and occasionally on the tail and feet. At necropsy, numerous white, multifocal and randomly distributed areas were seen on the liver. Gram-stained smears from skin and liver lesions showed Gram-negative bacilli arranged in clusters. Pure cultures of A. hydrophila were recovered from skin, internal organs and blood. Isolates were found to be susceptible to ceftiofur, amoxicillin + clavulanic acid, oxytetracycline, enrofloxacin, danofloxacin, neomycin, gentamicin, and lincomycin + neomycin. A pathogenicity test was performed using this isolate on 4 male 2-year-old New Zealand white rabbits. Local abscesses formed in 2 rabbits injected subcutaneously and the 2 that were injected intraperitoneally died as a result of septicaemia. In conclusion, this report has shown that A. hydrophila may cause skin lesions and even death due to septicaemia in crocodiles.

Kinerja probiotik Bacillus sp. pada pendederan benih ikan lele Clarias sp. yang diinfeksi Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

, Sukenda

2016-12-01

Full Text Available ABSTRACT This experiment was conducted to assess performance of Bacillus sp. probiotic on catfish juvenile Clarias sp. infected by Aeromonas hydrophila. The probiotic content in the diets were 0% (K+ and K-, 1%, and 2% in duplicates. This experiment used randomized design with four treatments and two replications. Juveniles with average body weight of 3.22±0.15 g/fish were reared in the 1.5×2.8×0.5 m3 pond with density of 800 fish/pond. Fish were reared for 30 days and fed three times a day at rate 8% of  total body weight. At day 31, catfish were challenged by A. hydrophila 0.1 mL (106 cfu/mL. Post infection observation was carried out ten days with density 10 fish/aquaria. The result showed that fish fed diet containing 2% probiotic gave the best probiotic performance with survival rate of catfish 83.33% after challenged, spesific growth rate 5.40%, and 0,75 of feed conversion ratio. The results of the blood profile showed significantly better results in the treatment of probiotics compared to the positive control after challenge test A. hydrophila. Probiotic Bacillus sp. has given as much as 2% on feed provides better performance on catfish juvenile. Keywords: probiotic, Bacillus sp., A. hydrophila, catfish juvenille, growth  ABSTRAK Penelitian ini bertujuan untuk menguji kinerja probiotik Bacillus sp. dalam pakan pada pendederan benih ikan lele Clarias sp. yang diinfeksi bakteri Aeromonas hydrophila. Penelitian ini menggunakan rancangan acak lengkap dengan empat perlakuan yaitu kandungan probiotik dalam pakan perlakuan yaitu 0% (K+ dan K-, 1%,  dan 2%, masing-masing dengan dua ulangan. Ikan lele yang digunakan memiliki bobot rata-rata 3,22±0,15 g/ekor, dipelihara dalam kolam terpal berukuran 1,5×2,8×0,5 m3 dengan kepadatan 800 ekor/kolam. Ikan dipelihara selama 30 hari dengan frekuensi pemberian pakan tiga kali sehari sebanyak 8% dari bobot tubuh ikan. Hari ke-31 benih lele diinjeksi bakteri A. hydrophila dosis 0,1 m

Phytochemical analysis of Binahong (Anredera Cordifolia) leaves extract to inhibit In Vitro growth of Aeromonas Hydrophila

Science.gov (United States)

Basyuni, Mohammad; Ginting, Prita Yulianti Anasta Br; Lesmana, Indra

2017-11-01

Binahong (Anredera cordifolia) is one of the medicinal plants commonly used to treat the disease of living organisms. The secondary metabolite of A. cordifolia leaves has been shown antibacterial activity. This study aimed to investigate the secondary metabolite of A. cordifolia leaves showing antibacterial and analysis the effectiveness of antibacterial to inhibit the growth of bacteria Aeromonas hydrophila. A paper disc soaked in a solution of A. cordifolia leaves extract was used to test in vitro at a concentration of 0% (w/v), 0.2%, 0.4%, 0.6%, 0.8%, and positive control of antibiotic (oxytetracycline), respectively. The extracts then placed on a tryptone soy agar (TSA) medium containing bacteria A. hydrophila and incubated at 37 °C for 24 hours. In vitro test showed that A. cordifolia leaves extract inhibited the growth of bacteria A. hydrophila with an inhibition area around the paper disc. The inhibition growth of A. hydrophila increased with the increasing of extract concentration. Bacterial growth was inhibited in the diameter zone of A. hydrophila under different levels of the extracts were 0 mm (0 % negative control), 8.4 mm (0.2 %), 9.4 mm (0.4 %), 10.5 mm (0.6 %), 11.9 mm (0.8 %), 27.5 mm (positive control), respectively. Phytochemical screening of A. cordifolia leaves extract indicated that the extracts contained flavonoid, phenol, saponin, alkaloid, triterpenoid, and β-sitosterol. Our in vitro study demonstrated the inhibition growth of A. hydrophila that caused the disease of motile Aeromonas septicemia (MAS).

Implication of lateral genetic transfer in the emergence of Aeromonas hydrophila isolates of epidemic outbreaks in channel catfish.

Directory of Open Access Journals (Sweden)

Mohammad J Hossain

Full Text Available To investigate the molecular basis of the emergence of Aeromonas hydrophila responsible for an epidemic outbreak of motile aeromonad septicemia of catfish in the Southeastern United States, we sequenced 11 A. hydrophila isolates that includes five reference and six recent epidemic isolates. Comparative genomics revealed that recent epidemic A. hydrophila isolates are highly clonal, whereas reference isolates are greatly diverse. We identified 55 epidemic-associated genetic regions with 313 predicted genes that are present in epidemic isolates but absent from reference isolates and 35% of these regions are located within genomic islands, suggesting their acquisition through lateral gene transfer. The epidemic-associated regions encode predicted prophage elements, pathogenicity islands, metabolic islands, fitness islands and genes of unknown functions, and 34 of the genes encoded in these regions were predicted as virulence factors. We found two pilus biogenesis gene clusters encoded within predicted pathogenicity islands. A functional metabolic island that encodes a complete pathway for myo-inositol catabolism was evident by the ability of epidemic A. hydrophila isolates to use myo-inositol as a sole carbon source. Testing of A. hydrophila field isolates found a consistent correlation between myo-inositol utilization as a sole carbon source and the presence of an epidemic-specific genetic marker. All epidemic isolates and one reference isolate shared a novel O-antigen cluster. Altogether we identified four different O-antigen biosynthesis gene clusters within the 11 sequenced A. hydrophila genomes. Our study reveals new insights into the evolutionary changes that have resulted in the emergence of recent epidemic A. hydrophila strains.

Effects of naturally occurring aquatic organic fractions on 241Am uptake by Scenedesmus obliquus (Chlorophyceae) and Aeromonas hydrophila (Pseudomonadaceae)

International Nuclear Information System (INIS)

Giesy, J.P. Jr.; Paine, D.

1977-01-01

Naturally occurring organics were extracted from water collected from Skinface Pond near Aiken, S.C. Organics were separated into four nominal diameter size fractions (I, greater than 0.0183; II, 0.0183 to 0.0032; III, 0.0032 to 0.0009; IV, less than 0.0009 μm) by membrane ultrafiltration and introduced into Scenedesmus obliquus and Aeromonas hydrophila cultures to determine their effects on 241 Am availability for uptake. Effects on 241 Am uptake were determined in actively growing S. obliquus cultures after 96 h of growth and in dense cultures of nongrowing cells after 4 h. Uptake by A. hydrophila was determined after 4 and 24 h in actively growing cultures. All organic fractions stimulated S. obliquus growth, with the most pronounced effects due to larger organic fractions, whereas no apparent growth stimulation of A. hydrophila was observed for any organic fraction. For both long-term and short-term studies, cellular 241 Am concentration (picocuries/cell) increased with increasing 241 Am concentration for S. obliquus and A. hydrophila. Fraction IV increased 241 Am uptake by both S. obliquus and A. hydrophila during 4-h incubations. During 96-h incubations fraction I was flocculated and cosedimented, with S. obliquus and A. hydrophila cells causing an apparent increase in 241 Am uptake. Fractions II and III reduced apparent 241 Am uptake by S. obliquus as a result of biological dilution caused by increased algal growth due to the organics. Fraction IV caused a reduction in 241 Am uptake by S. obliquus not attributable to biological dilution. Organics increased 241 Am uptake by A. hydrophila during 4- and 24-h incubations. A. hydrophila also caused flocculation of fraction I during 96-h incubations

UJI AKTIVITAS ANTIBAKTERI EKSTRAK RUMPUT LAUT Kappaphycus alvarezii DAN Eucheuma denticullatum TERHADAP BAKTERI Aeromonas hydrophila DAN Vibrio harveyii

Directory of Open Access Journals (Sweden)

Dwi Budi Wiyanto

2010-04-01

Full Text Available Penelitian tentang Uji Aktivitas Antibakteri Ekstrak Rumput Laut Kappaphycus alvarezii dan Eucheuma denticullatum Terhadap Bakteri Aeromonas hydrophila dan Vibrio harveyii dilakukan, mengingat banyak dijumpai  penyakit pada usaha budidaya ikan dan udang, terutama bakteri Aeromonas hydrophila dan Vibrio harveyii. Penelitian ini bertujuan untuk mengetahui efektifitas senyawa bioaktif rumput laut K. alvarezii dan E. denticullatum yang diekstrak menggunakan pelarut metanol dan etanol sebagai antibakteri terhadap A. hydrophila dan V. harveyii.  Penelitian dilakukan sebanyak dua tahap, yaitu: (1 Uji aktivitas antibakteri ekstrak rumput laut; dan (2 Analisa senyawa bioaktif yang terdapat pada ekstrak rumput laut, dimana masing-masing tahapan dianalisis menggunakan rancangan acak lengkap faktorial. Hasil penelitian menunjukkan, dua jenis ekstrak rumput laut dengan pelarut metanol dan etanol, mempunyai daya antibakteri terhadap A. hydrophila dan V. harveyii. Ekstrak E. denticullatum dengan pelarut metanol memiliki daya hambat lebih luas dibanding ekstrak K. alvarezii dengan pelarut metanol terhadap A. hydrophila (19.43±0,55 mm. Ekstrak E. denticullatum dengan pelarut metanol memiliki daya hambat lebih luas dibanding ekastrak K. alvarezii dengan pelarut metanol terhadap V. harveyii (19.85±0,23 mm. Asam heksadekanoat merupakan senyawa paling dominan dijumpai pada ekstrak rumput laut K. alvarezii, dan E. denticullatum yang diekstrak menggunakan pelarut metanol. Kata Kunci : Aktivitas Antibakteri, Rumput laut K. alvarezii dan E. denticullatum,  Bakteri A.  hydrophila dan V. harveyii. 

Identifikasi Gen Aerolysin dan Sensitivitas Antibiotik Aeromonas Hydrophila Penyebab Kematian Tukik (Lepidochelys olivacea di Pulau Serangan, Bali

Directory of Open Access Journals (Sweden)

Rima Ratnanggana Prasetya

2017-06-01

Full Text Available The purpose of this study was to evaluate the pathogene of Aeromonas hydrophila genes (Aerolysin as the cause of Lepidochelys olivacea death and to perform the antibiotic sensitivity test for antibiotic that often used in order to provide the best antibiotic treatment in the field case. The method used was the identification test using primary cultures on Tryptic Soy Agar (TSA and Mac Conkey Agar (MCA medium, then followed by Gram staining, oxidase, catalase, and biochemical tests. Then, aerolysin genes detection was performed by using Polymerase Chain Reaction (PCR method, while oxytetracycline, chloramphenicol, streptomycin, and kanamycin were tested for their sensitivity. From five samples of dead Lepidochelys olivacea, bleeding on the liver and intestine were observed. The identification result of bacteria was found A. hydrophila, and identified the gene encoding aerolysin. The antibiotic sensitivity test showed a sensitive category of A. hydrophila with a sensitivity level were oxytetracycline, chloramphenicol, kanamycin, and streptomycin. The main cause of Lepidochelys olivacea death in Turtle Conservation and Education Centre, Serangan Island, Bali was A. hydrophila which contains aerolysin genes, in which oxytetracycline seems to be the most effective drug for the treatment. ABSTRAK Tujuan dari penelitian ini adalah membuktikan adanya gen patogen (Aerolysin pada Aeromonas hydrophila sebagai penyebab kematian tukik penyu abu-abu serta mengetahui kepekaan obat antibiotic yang sering digunakan sehingga dapat memberikan terapi yang tepat pada kasus di lapangan. Metode penelitian yang digunakan adalah uji identifikasi menggunakan kultur primer pada media Tryptic Soy Agar (TSA dan Mac Conkey Agar (MCA, dilanjutkan uji pewarnaan Gram, uji oksidase, uji katalase, dan uji biokimiawi. Setelah itu dilakukan deteksi gen aerolysin menggunakan metode Polymerase Chain Reaction (PCR, serta dilakukan uji sensitivitas antibiotik oxytetracycline

Aeromonas hydrophila disturbs water and electrolyte transport in ...

African Journals Online (AJOL)

SERVER

2008-02-19

Feb 19, 2008 ... enterocytes with voluminous and spherical shape, disappearance of enterocyte brush border and lesions at ... (Paniagua et al., 1990) and causes different diseases. ... 22°C and the fish were fed on a standard diet composed of algae. ..... J (1998). Aeromonas hydrophila causes 'black diseases' in fairy.

Iqcg is essential for sperm flagellum formation in mice.

Directory of Open Access Journals (Sweden)

Ren-Ke Li

Full Text Available Mammalian spermatogenesis comprises three successive phases: mitosis phase, meiosis phase, and spermiogenesis. During spermiogenesis, round spermatid undergoes dramatic morphogenesis to give rise to mature spermatozoon, including the condensation and elongation of nucleus, development of acrosome, formation of flagellum, and removal of excessive cytoplasm. Although these transformations are well defined at the morphological level, the mechanisms underlying these intricate processes are largely unknown. Here, we report that Iqcg, which was previously characterized to be involved in a chromosome translocation of human leukemia, is highly expressed in the spermatogenesis of mice and localized to the manchette in developing spermatids. Iqcg knockout causes male infertility, due to severe defects of spermiogenesis and resultant total immobility of spermatozoa. The axoneme in the Iqcg knockout sperm flagellum is disorganized and hardly any typical ("9+2" pattern of microtubule arrangement could be found in Iqcg knockout spermatids. Iqcg interacts with calmodulin in a calcium dependent manner in the testis, suggesting that Iqcg may play a role through calcium signaling. Furthermore, cilia structures in the trachea and oviduct, as well as histological appearances of other major tissues, remain unchanged in the Iqcg knockout mice, suggesting that Iqcg is specifically required for spermiogenesis in mammals. These results might also provide new insights into the genetic causes of human infertility.

Lethal dose and clinical signs of Aeromonas hydrophila in Arapaima gigas (Arapaimidae), the giant fish from Amazon.

Science.gov (United States)

Dias, Marcia K R; Sampaio, Luciana S; Proietti-Junior, Aldo A; Yoshioka, Eliane T O; Rodrigues, Dália P; Rodriguez, Anselmo F R; Ribeiro, Ricardo A; Faria, Fernando S E D V; Ozório, Rodrigo O A; Tavares-Dias, Marcos

2016-05-30

Aeromonas hydrophila is causing substantial economic losses in world aquaculture. This study determined the tolerance limit (LD50-96h) of A. hydrophila in Arapaima gigas, and also investigated the clinical signs after intradermal inoculation. Arapaima gigas fingerlings were inoculated intraperitoneally with 0 (control), 1.0×10(5), 1.0×10(6), 1.0×10(7), 1.0×10(9) and 1.0×10(10)CFU/mL of A. hydrophila for the determination of LD50-96h, which was 1.8×10(8)CFU/mL. In another trial with intradermal inoculation of 1.8×10(8)CFU/mL A. hydrophila, there was a 91.6% of mortality between 8 and 23h, and several clinical signs were found. As follows: depigmentation in the tegument, lesions in the tail and fins, loss of balance, reduction of respiratory movements, hemorrhagic foci, necrotic hemorrhages in the kidney, liver and swim bladder, splenomegaly, ascites in the abdominal cavity and hyperemia, enlargement of the gall bladder, among other clinical signs observed. The results showed that A. gigas has a relative tolerance to A. hydrophila when compared to other Neotropical fish species. Copyright © 2016 Elsevier B.V. All rights reserved.

Aeromonas hydrophila disturbs water and electrolyte transport in ...

African Journals Online (AJOL)

Fish diseases create a menace to aquaculture farms. They provoke disastrous economic losses and sanitary risks for the consumer. The present study aims to investigate the effect of the bacteria, Aeromonas hydrophila on water and electrolyte (Na+, K+, Cl-, HCO3 -) flux of Mugil cephalus (L, 1758) intestine. Anterior, middle ...

Potential of Chromolaena odorata Leaf as A Cure of Aeromonas hydrophila on Giant Gouramy (Osphronemus gouramy

Directory of Open Access Journals (Sweden)

Y. Hadiroseyani

2007-07-01

Full Text Available This study was conducted to examine the potency of Chromolaena odorata leaf extract as a medicine for skin eruption disease caused by  Aeromonas hydrophila in giant gouramy Osphronemus gouramy.  Leaf extract of Chromolaena odorata for in vitro test was 0 (as control, 13000, 15000, 17000, 19000 and 21000 ppm, poured onto TSA medium containing bacteria 103 cfu/ml, and then is incubated for 24 hours. In vivo test was performed by injecting bacteria 0.1 ml of 109 cfu/ml intramuscularly into giant gouramy (14 g weight, and then  fish were maintained in the water containing 15000 ppm of Chromolaena odorata leaf extract. In vitro study showed that prevention area of leaf extract against Aeromonas hydrophila was increase by increasing the concentration of leaf extract used, reached 9,33 mm.  Prevention zone of leaf extract by difusion tends to constant, reached 7,6 mm. By in vivo test, survival rate of giant gouramy infected by Aeromonas hydrophila was no significantly different between dosages of leaf extract.  All treated fish, excluded control died after 24 hours infection. Keywords: Aeromonas hydrophila, Osphronemus gouramy, Chromolaena odorata   ABSTRAK Penelitian ini dilakukan untuk mengetahui potensi daun kirinyuh Chromolaena odorata sebagai obat untuk penyakit cacar yang diakibatkan oleh Aeromonas hydrophila pada ikan gurame Osphronemus gouramy. Konsentrasi ekstrak daun Chromolaena odorata untuk uji in vitro adalah 13000, 15000, 17000, 19000 dan 21000 serta 0 ppm sebagai kontrol, yang diletakkan di atas media TSA yang telah mengandung biakan bakteri 103 cfu/ml dan diinkubasi selama 24 jam. Uji in vivo dilakukan dengan menginjeksikan bakteri  sebanyak 0,1 ml (109 cfu/ml secara intramuskular ke ikan gurame (berat 14 g dan kemudian ikan dipelihara dalam air yang mengandung ekstrak daun kirinyuh 15000 ppm. Hasil uji in virto menunjukkan bahwa semakin tinggi konsentrasi ekstrak daun kirinyuh basah semakin efektif dalam menghambat perkembangan

Diarrea del viajero asociada a Aeromonas hydrophila Traveller's diarrohea caused by Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

M. L. Pita Toledo

2001-06-01

Full Text Available Aeromonas hydrophila es una bacteria que se encuentra frecuentemente en aguas dulces y salobres. Desde hace varios años se conoce que determinadas cepas de la especie pueden causar enfermedad en pescados y en anfibios, existiendo cierta controversia sobre su patogeneicidad en humanos. No obstante, puede dar lugar a infección en personas, que la adquieren bien a través de heridas abiertas o bien por ingestión de alimentos o agua contaminados. Sin embargo, en prácticamente la totalidad de las publicaciones se hace referencia a casos aislados más que a brotes producidos por esta bacteria. Generalmente la infección por A. hydrophila da lugar a gastroenteritis en personas sanas, pudiendo generar una septicemia en individuos inmunodeprimidos.En 1998 se produjo una alarma en el sector hotelero por un incremento considerable de los casos de gastroenteritis entre los turistas que acudían durante sus vacaciones a determinadas zonas costeras de la isla de Tenerife.Tras tener conocimiento de la situación, la Dirección General de Salud Pública inició una investigación epidemiológica con el objetivo de conocer la magnitud real del problema detectado e identificar los factores asociados a la misma, para poner en marcha las medidas correctoras y de control necesarias. El análisis inicial permitió determinar que se trataba de un proceso de gran magnitud en su extensión aunque de carácter leve, que afectaba únicamente a los turistas en una zona costera en concreto, compatible por lo tanto con la diarrea del viajero, planteándose un origen probablemente hídrico.Aeromonas hydrophila is a bacteria frequently found in fresh water and saline water. Certain strains of the species have been known to cause disease in fish and amphibians for several years, although some controversy exists about its ability to cause illness in humans. Nevertheless, either through open wounds or contaminated food or water, it can give rise to infection. However, almost

Transcriptome differences between enrofloxacin-resistant and enrofloxacin-susceptible strains of Aeromonas hydrophila.

Science.gov (United States)

Zhu, Fengjiao; Yang, Zongying; Zhang, Yiliu; Hu, Kun; Fang, Wenhong

2017-01-01

Enrofloxacin is the most commonly used antibiotic to control diseases in aquatic animals caused by A. hydrophila. This study conducted de novo transcriptome sequencing and compared the global transcriptomes of enrofloxacin-resistant and enrofloxacin-susceptible strains. We got a total of 4,714 unigenes were assembled. Of these, 4,122 were annotated. A total of 3,280 unigenes were assigned to GO, 3,388 unigenes were classified into Cluster of Orthologous Groups of proteins (COG) using BLAST and BLAST2GO software, and 2,568 were mapped onto pathways using the Kyoto Encyclopedia of Gene and Genomes Pathway database. Furthermore, 218 unigenes were deemed to be DEGs. After enrofloxacin treatment, 135 genes were upregulated and 83 genes were downregulated. The GO terms biological process (126 genes) and metabolic process (136 genes) were the most enriched, and the terms for protein folding, response to stress, and SOS response were also significantly enriched. This study identified enrofloxacin treatment affects multiple biological functions of A. hydrophila. Enrofloxacin resistance in A. hydrophila is closely related to the reduction of intracellular drug accumulation caused by ABC transporters and increased expression of topoisomerase IV.

Three-dimensional structure of the Trypanosome flagellum suggests that the paraflagellar rod functions as a biomechanical spring.

Directory of Open Access Journals (Sweden)

Louise C Hughes

Full Text Available Flagellum motility is critical for normal human development and for transmission of pathogenic protozoa that cause tremendous human suffering worldwide. Biophysical principles underlying motility of eukaryotic flagella are conserved from protists to vertebrates. However, individual cells exhibit diverse waveforms that depend on cell-specific elaborations on basic flagellum architecture. Trypanosoma brucei is a uniflagellated protozoan parasite that causes African sleeping sickness. The T. brucei flagellum is comprised of a 9+2 axoneme and an extra-axonemal paraflagellar rod (PFR, but the three-dimensional (3D arrangement of the underlying structural units is poorly defined. Here, we use dual-axis electron tomography to determine the 3D architecture of the T. brucei flagellum. We define the T. brucei axonemal repeating unit. We observe direct connections between the PFR and axonemal dyneins, suggesting a mechanism by which mechanochemical signals may be transmitted from the PFR to axonemal dyneins. We find that the PFR itself is comprised of overlapping laths organized into distinct zones that are connected through twisting elements at the zonal interfaces. The overall structure has an underlying 57 nm repeating unit. Biomechanical properties inferred from PFR structure lead us to propose that the PFR functions as a biomechanical spring that may store and transmit energy derived from axonemal beating. These findings provide insight into the structural foundations that underlie the distinctive flagellar waveform that is a hallmark of T. brucei cell motility.

Ciprofloxacin-Resistant Aeromonas hydrophila Cellulitis following Leech Therapy

Science.gov (United States)

Giltner, Carmen L.; Bobenchik, April M.; Uslan, Daniel Z.; Deville, Jaime G.

2013-01-01

We report a case of surgical site infection with ciprofloxacin-resistant Aeromonas hydrophila following leech therapy. Antimicrobial and genetic analyses of leech and patient isolates demonstrated that the resistant isolates originated from the leech gut microbiota. These data suggest that ciprofloxacin monotherapy as a prophylaxis regimen prior to leech therapy may not be effective in preventing infection. PMID:23363826

Quantitative Recovery of Aeromonas hydrophila from Nsukka Sewage

African Journals Online (AJOL)

Sewage samples were analyzed for the recovery of Aeromonas hydrophila. The pH of the samples ranged from 8.2 - 9.6 and the temperature from 20.0 – 28.7. Samples were enriched in alkaline peptone water medium (pH 8.4) before plating on different selective media. Media tested for the recovery of Aeromonas ...

The LBP Gene and Its Association with Resistance to Aeromonas hydrophila in Tilapia

Science.gov (United States)

Fu, Gui Hong; Liu, Feng; Xia, Jun Hong; Yue, Gen Hua

2014-01-01

Resistance to pathogens is important for the sustainability and profitability of food fish production. In immune-related genes, the lipopolysaccharide-binding protein (LBP) gene is an important mediator of the inflammatory reaction. We analyzed the cDNA and genomic structure of the LBP gene in tilapia. The full-length cDNA (1901 bp) of the gene contained a 1416 bp open reading frame, encoding 471 amino acid residues. Its genomic sequence was 5577 bp, comprising 15 exons and 14 introns. Under normal conditions, the gene was constitutively expressed in all examined tissues. The highest expression was detected in intestine and kidney. We examined the responses of the gene to challenges with two bacterial pathogens Streptcoccus agalactiae and Aeromonas hydrophila. The gene was significantly upregulated in kidney and spleen post-infection with S. agalactiae and A. hydrophila, respectively. However, the expression profiles of the gene after the challenge with the two pathogens were different. Furthermore, we identified three SNPs in the gene. There were significant associations (p tilapia resistant to A. hydrophila. PMID:25470022

The Efficacy of Nile Tilapia (Oreochromis niloticus Broodstock and Larval Immunization against Streptococcus agalactiae and Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

Wesly Pasaribu

2018-03-01

Full Text Available Streptococcus agalactiae and Aeromonas hydrophila have been recognized as the causative agents of mortality in tilapia larvae with single infection and coinfection. The objective of this study was to evaluate the efficacy of maternal transfer and offspring protection from the immunization of monovalent and bivalent vaccines on Nile tilapia (Oreochromis niloticus broodstock and larval immunization. Four groups of broodstock were intraperitoneally injected with formalin killed whole-cells of S. agalactiae (Sa group, A. hydrophila (Ah group, the bivalent mixed vaccine of them (Biv group, and phosphate-buffered saline as a control (Pbs group. Immunization of the larvae produced from immunized broodstock with a bivalent vaccine (Biv1 group and Pbs (Pbs1 group was performed by immersion at 20 days after hatch. Larvae produced from the Pbs group were unvaccinated as the control (Pbs2 group. Changes in the specific antibody and relative percent survival were measured. The Sa and Ah groups that could increase specific antibodies and protection against pathogenic bacteria were challenged with the homologous bacteria. The Biv group stimulated and protected against both S. agalactiae and A. hydrophila. The specific antibody of the Biv1 group was higher than the Pbs1 and Pbs2 groups. The last observation in this study showed that the relative percent survival of the Biv group after challenged S. agalactiae, A. hydrophila, and coinfection were 74.74 ± 3.18%, 73.81 ± 8.58%, and 71.48 ± 5.70%, respectively. The use of bivalent vaccines on the broodstock and larvae may be a strategy to reduce mortality in Nile tilapia larvae caused by single pathogen infection of S. agalactiae and A. hydrophila, or coinfection with both S. agalactiae and A. hydrophila.

A new species in section Hydrophilae of the genus Psathyrella

NARCIS (Netherlands)

Marchetti, Mauro

1993-01-01

A new species of Psathyrella (Section Hydrophilae) is described from a mediterranean coastal pine forest (Pinus pinaster, Pinus pinea) in Italy, that was burnt on July 31st, 1989. It is dedicated to Dr. E. Kits van Waveren.

PENGGUNAAN EKSTRAK DAUN SIRIH (Piper betle Linn UNTUK MENGHAMBAT BAKTERI Aeromonas hydrophila DAN TOKSISITASNYA PADA IKAN PATIN (Pangasius hypophthalmus (THE USE OF PIPER BETLE LINN EXTRACT ON AEROMONAS HYDROPHILA TO OBSTRUCT AND THE TOKSISITY TO PANGASIUS HYPOPHTHALMUS

Directory of Open Access Journals (Sweden)

Siti Aisiah

2016-06-01

Full Text Available Tujuan penelitian ini untuk mengetahui   daya  hambat  daun  sirih   yang  paling  besar  terhadap  bakteri Aeromonas Hydrophila, mengetahui konsentrasi minimal ekstrak daun sirih yang mampu menghambat pertumbuhan bakteri  A. hydrophila  dan mengetahui toksisitas konsentrasi efektif dari  ekstrak daun sirih terhadap ikan patin. Rancangan percobaan yang digunakan untuk  uji toksisitas  adalah rancangan acak lengkap, terdiri dari 4 perlakuan yaitu A  = Ikan disuntik dengan ekstrak daun sirih konsentrasi 75%, B  = Ikan disuntik dengan ekstrak daun sirih konsentrasi 25%, C  = Kontrol positif (ikan disuntik dengan akuades steril dan D  = Kontrol negatif (ikan tidak disuntik, diulang 3 kali. Hasil uji sensitivitas antibakteri daun sirih yang mempunyai daya hambat dan daya bunuh paling besar terhadap bakteri A. hydrophila adalah ekstrak daun sirih-metanol. Pengujian MIC menunjukkan bahwa ekstrak daun sirih-metanol memiliki daya hambat minimal 25 % terhadap aktivitas bakteri A. hydrophila. Hasil uji toksisitas yang dilakukan terhadap ikan patin dengan konsentrasi 75% dan 25% menunjukkan bahwa mortalitas yang terjadi tidak mencapai 50%. Pengamatan hematologis pada masing-masing perlakuan menunjukkan hasil yang berpengaruh tidak nyata terhadap kesehatan ikan patin. Parameter kualitas air pada penelitian ini yaitu, , kadar oksigen terlarut,  pH, amoniak, CO2 dan suhu masih dapat mendukung kehidupan ikan patin. This research was aimed a finding the part of Piper betle Linn  which had the biggest resistance to Aeromonas hydrophila bacteria and to know the minimal concentrate which could obstruct the growth of A. hydrophila  bacteria and to know effective concentrate toxicity of P. betle Linn  to Pangasius hypophthalmus.  The random sampling used proportionate stratified random sampling. In toxicity test, it had be done 4 treatment, which was given to fish, those were : A = fish was injected with 25 % concentrate of extract  P

Spatial ecology of the coachwhip, Masticophis flagellum (Squamata: Colubridae), in eastern Texas

Science.gov (United States)

Richard W. Johnson; Robert R. Fleet; Michael B. Keck; D. Craig Rudolph

2007-01-01

We radio-tracked nine Masticophis flagellum (Coachwhips) to determine home range, habitat use, and movements in eastern Texas from April to October 2000. Home ranges of Coachwhips contained more oak savanna macrohabitat than early-successional pine plantation or forested seep, based on the availability of these three macrohabitats in the study area....

THE STRUCTURE, ORIGIN, ISOLATION, AND COMPOSITION OF THE TUBULAR MASTIGONEMES OF THE OCHROMONAS FLAGELLUM

Science.gov (United States)

Bouck, G. Benjamin

1971-01-01

The structure, assembly, and composition of the extracellular hairs (mastigonemes) of Ochromonas are detailed in this report. These mastigonemes form two lateral unbalanced rows, each row on opposite sides of the long anterior flagellum. Each mastigoneme consists of lateral filaments of two distinct sizes attached to a tubular shaft. The shaft is further differentiated into a basal region at one end and a group of from one to three terminal filaments at the free end. Mastigoneme ontogeny as revealed especially in deflagellated and regenerating cells appears to begin by assembly of the basal region and shaft within the perinuclear continuum. However, addition of lateral filaments to the shaft and extrusion of the mastigonemes to the cell surface is mediated by the Golgi complex. The ultimate distribution of mastigonemes on the flagellar surface seems to be the result of extrusion of mastigonemes near the base of the flagellum, and it is suggested that mastigonemes are then pulled up the flagellum as the axoneme elongates. Efforts to characterize mastigonemes biochemically after isolation and purification on cesium chloride (CsCl) followed by electrophoresis on acrylamide gels have demonstrated what appear to be a single major polypeptide and several differentially migrating carbohydrates. The polypeptide is not homologous with microtuble protein. The functionally anomalous role of mastigonemes in reversing flagellar thrust is discussed in relation to their distribution relative to flagellar anatomy and to the plane of flagellar undulations. PMID:5123323

Assessment of Skin Pathological Responses in the Yellowfin Seabream (Acanthopagrus latus under the Aeromonas hydrophila Exposure

Directory of Open Access Journals (Sweden)

Fatemeh Azadbakht

2018-01-01

Full Text Available Background: Bacterial diseases in cultured fish are considered the main problem to aquaculture system. Skin is the structure that covers the body in fish. Skin histopatological alterations were used to assess the effects of Aeromonas hydrophila exposure on the yellowfin seabream Acanthopagrus latus(. Methods: In this regard, 90 A. latus were exposed to sublethal concentrations of A. hydrophila (103,106 CFU/ml for 3 weeks. Results: Some more severe alternations found in the skin of fish exposed. The most frequent histopathological changes detected in the skin including hyperplasia of epidermis, hypertrophy and hyperplasia of the mucosal cells and dermis edema. Some more severe alternations found in the skin of fish exposed to higher level of A. hydrophila (106 CFU/ml included telangiectasia of dermis layer. In addition, according to the results of histometrical studies in treated fish compared to control group showed that thickness of epidermis and dermis layers were increased significantly (P<0.05. Conclusion: A. hydrophila can cause major histophatological changes in the skin of A. latus. In addition, histopathological changes of the skin provide helpful information about the environmental conditions and as particular biomarkers may provide imminent into evaluating the general health and stress status of fish.

Effects of dietary Lactobacillus plantarum and AHL lactonase on the control of Aeromonas hydrophila infection in tilapia.

Science.gov (United States)

Liu, Wenshu; Ran, Chao; Liu, Zhi; Gao, Qian; Xu, Shude; Ringø, Einar; Myklebust, Reidar; Gu, Zemao; Zhou, Zhigang

2016-08-01

This study addressed the effects of dietary Lactobacillus plantarum or/and N-acylated homoserine lactonase (AHL lactonase) on controlling Aeromonas  hydrophila infection in juvenile hybrid tilapia (Oreochromis niloticus♀ × O. aureus ♂). Fish were fed Lb. plantarum subsp. plantarum strain JCM1149 (10(8)  CFU/g feed) or/and AHL lactonase AIO6 (4 U/g) and were exposed to a chronic challenge of A. hydrophila NJ-1 (10(5)  cells/mL) for 14 days. Intestinal (foregut) alkaline phosphatase (IAP) activities were evaluated 1 day post challenge to reflect the resistance of fish against A. hydrophila infection. Parallel groups of fish with the same dietary assignments while unchallenged were also included to investigate the effect of dietary Lb. plantarum or/and AIO6 supplementation on gut health of tilapia. The results showed that IAP activity was significantly lower in fish fed with diets supplemented with Lb. plantarum JCM1149 or the combination of Lb. plantarum JCM1149 and AIO6, indicating enhanced resistance against A. hydrophila. Light microscopy and transmission electron microscopy images of foregut revealed damage caused by A. hydrophila NJ-1, but dietary Lb. plantarumJCM1149 or/and AIO6 significantly alleviated the damages. Compared to the fish immersed in A. hydrophila NJ-1, dietary Lb. plantarum JCM1149 or AIO6 could maintain the microvilli length in the foregut of tilapia. However, among the unchallenged groups of fish, the microvilli length in the foregut of tilapia fed AIO6 (singly or combination) and the microvilli density of tilapia fed AIO6 (singly) were significantly lower than those of the control, though the microvilli density in the combination treatment was significantly improved. Additionally, the dietary Lb. plantarum JCM1149 could down-regulate the expression of stress-related gene in the gut after the acute phase. In conclusion, the dietary Lb. plantarum JCM1149 is recommended to control the A. hydrophila infection in

Melanization and Pathogenicity in the Insect, Tenebrio molitor, and the Crustacean, Pacifastacus leniusculus, by Aeromonas hydrophila AH-3

Science.gov (United States)

Noonin, Chadanat; Jiravanichpaisal, Pikul; Söderhäll, Irene; Merino, Susana; Tomás, Juan M.; Söderhäll, Kenneth

2010-01-01

Aeromonas hydrophila is the most common Aeromonas species causing infections in human and other animals such as amphibians, reptiles, fish and crustaceans. Pathogenesis of Aeromonas species have been reported to be associated with virulence factors such as lipopolysaccharides (LPS), bacterial toxins, bacterial secretion systems, flagella, and other surface molecules. Several mutant strains of A. hydrophila AH-3 were initially used to study their virulence in two animal species, Pacifastacus leniusculus (crayfish) and Tenebrio molitor larvae (mealworm). The AH-3 strains used in this study have mutations in genes involving the synthesis of flagella, LPS structures, secretion systems, and some other factors, which have been reported to be involved in A. hydrophila pathogenicity. Our study shows that the LPS (O-antigen and external core) is the most determinant A. hydrophila AH-3 virulence factor in both animals. Furthermore, we studied the immune responses of these hosts to infection of virulent or non-virulent strains of A. hydrophila AH-3. The AH-3 wild type (WT) containing the complete LPS core is highly virulent and this bacterium strongly stimulated the prophenoloxidase activating system resulting in melanization in both crayfish and mealworm. In contrast, the ΔwaaE mutant which has LPS without O-antigen and external core was non-virulent and lost ability to stimulate this system and melanization in these two animals. The high phenoloxidase activity found in WT infected crayfish appears to result from a low expression of pacifastin, a prophenoloxidase activating enzyme inhibitor, and this gene expression was not changed in the ΔwaaE mutant infected animal and consequently phenoloxidase activity was not altered as compared to non-infected animals. Therefore we show that the virulence factors of A. hydrophila are the same regardless whether an insect or a crustacean is infected and the O-antigen and external core is essential for activation of the proPO system

Melanization and pathogenicity in the insect, Tenebrio molitor, and the crustacean, Pacifastacus leniusculus, by Aeromonas hydrophila AH-3.

Directory of Open Access Journals (Sweden)

Chadanat Noonin

Full Text Available Aeromonas hydrophila is the most common Aeromonas species causing infections in human and other animals such as amphibians, reptiles, fish and crustaceans. Pathogenesis of Aeromonas species have been reported to be associated with virulence factors such as lipopolysaccharides (LPS, bacterial toxins, bacterial secretion systems, flagella, and other surface molecules. Several mutant strains of A. hydrophila AH-3 were initially used to study their virulence in two animal species, Pacifastacus leniusculus (crayfish and Tenebrio molitor larvae (mealworm. The AH-3 strains used in this study have mutations in genes involving the synthesis of flagella, LPS structures, secretion systems, and some other factors, which have been reported to be involved in A. hydrophila pathogenicity. Our study shows that the LPS (O-antigen and external core is the most determinant A. hydrophila AH-3 virulence factor in both animals. Furthermore, we studied the immune responses of these hosts to infection of virulent or non-virulent strains of A. hydrophila AH-3. The AH-3 wild type (WT containing the complete LPS core is highly virulent and this bacterium strongly stimulated the prophenoloxidase activating system resulting in melanization in both crayfish and mealworm. In contrast, the ΔwaaE mutant which has LPS without O-antigen and external core was non-virulent and lost ability to stimulate this system and melanization in these two animals. The high phenoloxidase activity found in WT infected crayfish appears to result from a low expression of pacifastin, a prophenoloxidase activating enzyme inhibitor, and this gene expression was not changed in the ΔwaaE mutant infected animal and consequently phenoloxidase activity was not altered as compared to non-infected animals. Therefore we show that the virulence factors of A. hydrophila are the same regardless whether an insect or a crustacean is infected and the O-antigen and external core is essential for activation of the

Antimicrobial activity of some of the south-Indian spices against serotypes of Escherichia coli, Salmonella, Listeria monocytogenes and Aeromonas hydrophila Atividade antimicrobiana de condimentos do sul da India sobre Escherichia coli, Salmonella, Listeria monocytogenes e Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

M.N. Indu

2006-06-01

Full Text Available Antibacterial activity of extracts of Allium sativum (garlic, Myristica fragrans (nutmeg, Zingiber officinale (ginger, Allium cepa (onion and Piper nigrum (pepper has been evaluated against 20 different serogroups of Escherichia coli, 8 serotypes of Salmonella, Listeria monocytogenes and Aeromonas hydrophila. Garlic extract showed excellent antibacterial activity against all the test organisms, except L. monocytogenes. Nutmeg showed good anti-listerial activity, although activity against E. coli and Salmonella were serotype dependent. Both garlic and nutmeg extracts were effective against A. hydrophila. Extracts of ginger showed inhibitory activity against two serogroups of E. coli: as O8 (enterotoxigenic E. coli and O88 only. Extracts of onion and pepper did not show any antibacterial activity against the test organisms.Avaliou-se a atividade antimicrobiana de extratos de alho (Allium sativum, noz-moscada (Mysritica frangrans, gengibre (Zingiber officinale cebola (Allium cepa e pimenta do reino (Piper nigrum sobre 20 sorotipos de Escherichia coli, 8 sorotipos de Salmonella, Listeria monocytogenes e Aeromonas hydrophila. O alho apresentou atividade antimicrobiana excelente sobre todos os microrganismos testados, excepto L. monocytogenes. A noz-moscada apresentou boa atividade antilisteria, emboara atividade sobre E. coli e Salmonella tenha sido sorotipo-dependente. Tanto alho como noz-moscada foram eficientes contra A. hydrophila. O extrato de gengibre apresentou atividade inibitória sobre dois sorotipos de E. coli: 08 (enterotoxigenico e 088. Os extratos de cebola e pimenta do reino não apresentaram nenhuma atividade contra os microrganismos testados.

In vitro antimicrobial activity of ethanolic extracts obtained from Ficus spp. leaves against the fish pathogen Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

Tkachenko Halyna

2016-12-01

Full Text Available The main goal of this study was to determine in vitro antimicrobial activity of ethanolic extracts obtained from the leaves of various Ficus species against Aeromonas hydrophila isolated locally from infected rainbow trout (Oncorhynchus mykiss Walbaum with the aim of providing scientific rationale for the use of the plant in the treatment of bacterial infections induced by Aeromonas spp. in fish. Antimicrobial susceptibility testing was done on Muller-Hinton agar with the disc diffusion method. In the present study, most ethanolic extracts proved effective against the A. hydrophila tested, with 10-12 mm inhibition zones observed. A. hydrophila demonstrated the highest susceptibility to F. pumila. Among various species of Ficus with moderate activity against A. hydrophila, the highest antibacterial activities were noted for F. benghalensis, F. benjamina, F. deltoidea, F. hispida, and F. lyrata. Thus, Ficus can be used as a natural antiseptic and antimicrobial agent in veterinary practice. Further investigations need to be conducted to isolate and identify the bioactive compounds that can then be subjected to detailed pharmacological studies and the development of clinical applications. The alarming rate of increasing resistance in bacterial pathogens in aquaculture environments means that medicinal plants with antibacterial properties are very important as natural resources of new active compounds.

Impact of thermal loading and other water quality parameters on the epizootiology of Aeromonas hydrophila infections of centrarchids

International Nuclear Information System (INIS)

Esch, G.W.; Hazen, T.C.

1979-01-01

During the current contract year, the following results were obtained: (1) Data from field-generated studies have shown that hematocrit, hemoglobin, total red blood cell counts, total white blood cell counts, and cortisol levels are significantly affected in largemouth bass with body conditions < 2.0, suggesting that stress, body condition, and the probability of bass acquiring red-sore disease are related. Laboratory studies appear to at least partially confirm these results. (2) Chemotaxis studies show that Aeromonas hydrophila is attracted to specific sugars and amino acids and that there appears to be a strain-related affect of fish mucous on A. hydrophila isolated from red-sore lesions. (3) Immunologic and serologic tests suggest that A. hydrophila isolated from red-sore lesions on bass from one lake system will not cross-react with antibodies in sera isolated from bass in another lake system, suggesting the existence of different strains in different lakes

Aerocistite aguda induzida por tioglicolato, lipolisacarídeo e Aeromona hydrophila inativada em Piaractus mesopotamicus: efeitos hematológicos

Directory of Open Access Journals (Sweden)

Julieta Rodini Engrácia de Moraes

2012-10-01

Full Text Available Os efeitos da injeção de tioglicolato, lipolissacarídio de Escherichia coli e Aeromonas hydrophila inativada na bexiganatatória de pacus, Piaractus mesopotamicus (Characidae foram avaliados quanto às respostas de células vermelhas,leucócitos e trombócitos do sangue. Ensaios quantitativos de eritrócitos, leucócitos e trombócitos foram realizados6, 24 e 48 h após os estímulos e comparados com peixes que receberam solução salina 0,65% pela mesma via. Peixes inoculados com A. hydrophila apresentaram redução do número de eritrócitos e da taxa de hemoglobina enquanto ohematócrito aumentou 6 h após o estímulo. Os resultados mostraram que o tioglicolato e o LPS também induziram redução da hemoglobina e aumento do hematócrito. A contagem de trombócitos diminuiu 6 h após a inoculação deA. hydrophila inativada e aumentou 48 horas após a injeção de LPS. A contagem de leucócitos aumentou 6 h após ainoculação de A. hydrophila enquanto a de linfócitos a leucócitos granulares PAS positivos (PAS_LG diminuiu 24 hdepois. Peixes injetados com tioglicolato o LPS apresentaram aumento do número de LG_PAS em relação aos inoculadoscom A. hydrophila inativada ou grupo controle. A contagem de monócitos não foi afetada pelos diferentes agentes.

Hesperidin Inhibits Inflammatory Response Induced by Aeromonas hydrophila Infection and Alters CD4+/CD8+ T Cell Ratio

Directory of Open Access Journals (Sweden)

Abdelaziz S. A. Abuelsaad

2014-01-01

Full Text Available Background. Aeromonas hydrophila is an opportunistic bacterial pathogen that is associated with a number of human diseases. Hesperidin (HES has been reported to exert antioxidant and anti-inflammatory activities. Objectives. The aim of this study was to investigate the potential effect of HES treatment on inflammatory response induced by A. hydrophila infection in murine. Methods. A. hydrophila-infected mice were treated with HES at 250 mg/kg b.wt./week for 4 consecutive weeks. Phagocytosis, reactive oxygen species production, CD4+/CD8+ T cell ratio, and CD14 expression on intestinal infiltrating monocytes were evaluated. The expression of E-selectin and intercellular adhesion molecule 1 on stimulated HUVECs and RAW macrophage was evaluated. Results. Percentage of CD4+ T cells in the intestinal tissues of infected treated mice was highly significantly increased; however, phagocytic index, ROS production, CD8+ T cells percentage, and CD14 expression on monocytes were significantly reduced. On the other hand, HES significantly inhibited A-LPS- and A-ECP-induced E-selectin and ICAM-1 expression on HUVECs and ICAM-1 expression on RAW macrophage. Conclusion. Present data indicated that HES has a potential role in the suppression of inflammatory response induced by A. hydrophila toxins through downmodulation of ROS production and CD14 and adhesion molecules expression, as well as increase of CD4+/CD8+ cell ratio.

Therapeutic effects of marshmallow (Althaea officinalis L.) extract on plasma biochemical parameters of common carp infected with Aeromonas hydrophila.

Science.gov (United States)

Banaee, Mahdi; Soleimany, Vahid; Nematdoost Haghi, Behzad

2017-01-01

This study evaluated preclinical and clinical safety of marshmallow ( Althaea officinalis L.) extract as a naturopathic medicine in common carp deliberately infected with Aeromonas hydrophila . The fish were fed 0 (control), 2.50, 5.00 and 10.00 g of marshmallow extract for 60 days in a preclinical experiment and then, challenged with A. hydrophila for a 10-day experiment. Significant increases were observed in aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), creatine phosphokinase (CPK) activities and plasma creatinine levels in fish fed 10 g marshmallow extract per kg feed. However, alanine aminotransferase (ALT) significantly decreased on day 60. The fish fed 2.50 g marshmallow extract per kg feed indicated increased levels of total protein and globulin. There were no significant changes in albumin levels ( p > 0.05). 2.50 and 5.00 g marshmallow significantly decreased triglyceride and cholesterol levels and increased glucose levels ( p Marshmallow extract at 5.00 and 10.00 g can adjust plasma biochemical parameters in fish challenged with A. hydrophila . The results of preclinical studies and pharmaceutical toxicity of marshmallow extract revealed that dietary levels lower than 5.00 g were safe and effective. The results of this clinical study demonstrated that marshmallow extract (5.00 g kg -1 feed) can protect fish against A. hydrophila .

Crystallization and initial X-ray analysis of polyhydroxyalkanoate granule-associated protein from Aeromonas hydrophila

Energy Technology Data Exchange (ETDEWEB)

Zhao, Minglian; Li, Zhenguo; Zheng, Wei; Lou, Zhiyong [MOE Key Laboratory of Protein Science, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084 (China); Chen, Guo-Qiang, E-mail: chengq@stu.edu.cn [MOE Key Laboratory of Protein Science, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084 (China); Multidisciplinary Research Center, Shantou University, Shantou 515063, Guangdong (China)

2006-08-01

The phasin PhaP{sub Ah} from A. hydrophila strain 4AK4 was crystallized using the hanging-drop vapour-diffusion method. Polyhydroxyalkanoate (PHA) granule-associated proteins (phasins) were discovered in PHA-accumulating bacteria. They play a crucial role as a structural protein during initial PHA-granule formation and granule growth and also serve as interfaces for granule stabilization in vivo. The phasin PhaP{sub Ah} from Aeromonas hydrophila strain 4AK4 was crystallized using the hanging-drop vapour-diffusion method. Single crystals were cryocooled for X-ray diffraction analysis. The phasin crystals belonged to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 80.8, b = 108.9, c = 134.4 Å.

Effect of Gamma Radiation and Microwave Cooking on Aeromonas Hydrophila in Bolti Fish Fillet

International Nuclear Information System (INIS)

Mohamad, W.S.; Megahed, A.A.; El-Ghaiaty, H.A.; Hafez, T.A.

2016-01-01

The objective of this study is to determine the bactericidal effect of gamma and microwave radiation on Aeromonas hydrophila inoculated in fish fillets. The study revealed that treatment of fish fillets with a dose of 1 kGy gamma radiation reduced the population of A.hydrophila by 104 cfu/g, while the dose of 2 and 3 kGy completely eliminated the microorganism. Treatment of fish fillets with microwave cooking for 1 and 2 minutes completely eliminated the microorganism. The physical examination of fish after gamma radiation treatment revealed that the used doses had no significant changes on fish fillets. The changes in protein profile (amino acids %) depended on radiation dose and period of cooking in microwave alongside controls while the total protein content was not affected.

Therapeutic effects of marshmallow (Althaea officinalis L.) extract on plasma biochemical parameters of common carp infected with Aeromonas hydrophila

OpenAIRE

Banaee, Mahdi; Soleimany, Vahid; Nematdoost Haghi, Behzad

2017-01-01

This study evaluated preclinical and clinical safety of marshmallow (Althaea officinalis L.) extract as a naturopathic medicine in common carp deliberately infected with Aeromonas hydrophila. The fish were fed 0 (control), 2.50, 5.00 and 10.00 g of marshmallow extract for 60 days in a preclinical experiment and then, challenged with A. hydrophila for a 10-day experiment. Significant increases were observed in aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase ...

Building a flagellum in biological outer space

Directory of Open Access Journals (Sweden)

Lewis D. B. Evans

2014-01-01

Full Text Available Flagella, the rotary propellers on the surface of bacteria, present a paradigm for how cells build and operate complex molecular ‘nanomachines’. Flagella grow at a constant rate to extend several times the length of the cell, and this is achieved by thousands of secreted structural subunits transiting through a central channel in the lengthening flagellum to incorporate into the nascent structure at the distant extending tip. A great mystery has been how flagella can assemble far outside the cell where there is no conventional energy supply to fuel their growth. Recent work published by Evans et al.[Nature (2013 504: 287-290], has gone some way towards solving this puzzle, presenting a simple and elegant transit mechanism in which growth is powered by the subunits themselves as they link head-to-tail in a chain that is pulled through the length of the growing structure to the tip. This new mechanism answers an old question and may have resonance in other assembly processes.

LD5o of the bacteria Aeromonas hydrophila to matrinxã, Brycon amazonicus DL5o da bactéria Aeromonas hydrophila para o matrinxã, Brycon amazonicus

Directory of Open Access Journals (Sweden)

Sarah Ragonha de Oliveira

2011-01-01

Full Text Available In order to determine the lethal dose (96-h LD50 of the bacteria Aeromonas hydrophila to matrinxã, Brycon amazonicus, to be applied in challenge tests, 90 fish (63.23 ± 6.39 g were divided into five treatments, with different bacterial solutions: T1 - Control (0.9% NaCl saline solution; T2 (4 x 10(11 cells/ mL; T3 (5 x 10(11 cells/ mL; T4 (1.36 x 10(12 cells/ mL and T5 (3.06 x 10(12 cells/ mL. Fish were previously anesthetized with benzocaine (60 mg L-1, inoculated in the peritoneal cavity with the bacterial suspensions and then distributed into fifteen 80-L test chambers, where the water variables were monitored and fish mortality was observed. The experiment was randomly designed in three replicates and the 96-h LD50 was estimated according to the trimmed Spearman-Karber method. Water quality variables remained within adequate ranges for fish health and performance. Fish mortality rate increased with the bacterial concentrations of A. hydrophila (T1 = 0%; T2 = 16.66%; T3 = 44.44%; T4 = 72.22% and T5 = 100%, and the first mortalities were observed after 57 h, although the signs of the bacterial infection were already observed 24 h after the inoculation. The results indicate that the 96-h LD50 value of A. hydrophila to matrinxã is 6.66 x 10(11 cells/ mL.Para determinar a dose letal (DL50 96-h da bactéria Aeromonas hydrophila para o matrinxã, Brycon amazonicus, com aplicabilidade para testes de desafio, foram utilizados 90 peixes (63,23 ± 6,39 g, divididos em cinco tratamentos, com diferentes soluções bacterianas: T1 - Controle (solução salina 0,9% NaCl; T2 (4 x 10(11 células/ mL; T3 (5 x 10(11 células/ mL-1; T4 (1,36 x 10(12 células/mL-1 e T5 (3,06 x 10(12 células/ mL-1. Os peixes foram previamente anestesiados com benzocaína (60 mg L-1, inoculados na cavidade peritoneal com as suspensões bacterianas e distribuídos em 15 aquários de vidro de 80 L de capacidade, com aeração constante. O experimento teve duração de 96 h, no

Protective effect of probiotic diets on haematobiochemical and histopathology changes of Mystus montanus (Jerdon 1849 against Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

Gurusamy Chelladurai

2013-11-01

Full Text Available Objectives: To evaluate the protective effect of probiotic diets on haemotobiochemical and histopathology changes of Mystus montanus against Aeromonas hydrophila (A. hydrophila. Methods: Three experimental groups of fish were fed with a diet supplemented with Lactobacillus acidophilus (L. acidophilus (Sporolac, comprising about 0.1 g, 0.2 g and 0.3 g. Control group of fish were fed without L. acidophilus. After 60 d of feeding the fishes in experimental group were injected with 1 mL of A. hydrophila and were supplemented with probiotic diets. The control group fishes were injected with 1 mL of physiological saline solution alone. Results: Blood samples were collected for haematobiochemical analysis, while samples of the liver, and gills were examined for path histology after 7 d of infection. The result showed that the growth parameters, weight gain, specific growth rate were better in infected group maintained on the probiotic diet compared to those in control group. The haematology parameters, erythrocyte sedimentation rate, red blood cell, white blood cell, total serum protein, Mg 2+ , Ca 2+ , Cl, glucose, cholesterol and total immunoglobulin concentration and the pathohistology of the liver, gills were better in the infected fish maintained on the probiotic diet than those in the group fed the control diet. Conclusions: The result of the present study showed that L. acidophilus is useful as a probiotic agent in Mystus montanus against A. hydrophila.

Aeromonas hydrophila urinary tract infection in pregnancy- Case report and literature review

OpenAIRE

Ragunathan, Latha; Kavitha, Kannaiyan; Raveendran, Vinod; Dhandapani, Senthil Pragash; Jaget, Nirmala; Kannivelu, Jayanthi

2012-01-01

A case of a pregnant woman without previous or concomitant disease, who developed an Aeromonas hydrophila urinary tract infection (UTI) at 12 weeks gestation, is reported. A brief review of the literature on the association and incidence of Aeromonas spp in urinary infections and also in association with pregnancy is presented.

POTENTIAL FOR GREAT EGRETS (ARDEA ALBA) TO TRANSMIT A VIRULENT STRAIN OF AEROMONAS HYDROPHILA AMONG CHANNEL CATFISH (ICTALURUS PUNCTATUS) CULTURE PONDS.

Science.gov (United States)

Jubirt, Madison M; Hanson, Larry A; Hanson-Dorr, Katie C; Ford, Lorelei; Lemmons, Scott; Fioranelli, Paul; Cunningham, Fred L

2015-07-01

Aeromonas hydrophila is a gram-negative, rod-shaped, facultative, anaerobic bacterium that is ubiquitous in freshwater and slightly brackish aquatic environments and infects fish, humans, reptiles, and birds. Recent severe outbreaks of disease in commercial channel catfish (Ictalurus punctatus) aquaculture ponds have been associated with a highly virulent A. hydrophila strain (VAH), which is genetically distinct from less-virulent strains. The epidemiology of this disease has not been determined. Given that A. hydrophila infects birds, we hypothesized that fish-eating birds may serve as a reservoir for VAH and spread the pathogen by flying to uninfected ponds. Great Egrets (Ardea alba) were used in this transmission model because these wading birds frequently prey on farmed catfish. Great Egrets that were fed VAH-infected catfish shed VAH in feces demonstrating their potential to spread VAH.

Concentração inibitória mínima de oxitetraciclina para isolados de Aeromonas Hydrophila obtidos de diferentes fontes Minimal inhibitory concentration to oxitetracycline in Aeromonas Hydrophila strains isolated from different sources

Directory of Open Access Journals (Sweden)

Delton José Pereira Júnior

2006-12-01

Full Text Available Objetivou-se com este trabalho determinar a concentração inibitória mínima (MIC de oxitetraciclina para isolados de Aeromonas hydrophila obtidos de pescado, água de cultivo de peixes e casos de septicemia hemorrágica em peixes. Foi determinado MIC de 100 isolados de A. hydrophila, oriundos de 12 pisciculturas localizadas nos Estados de Minas Gerais, Rio de Janeiro e Rio Grande do Sul, utilizando a técnica de macrodiluição em caldo. Os resultados demonstraram que 14 isolados apresentaram MIC>100 µg/mL (resistentes e 86 apresentaram MICThe aim of this paper was to determine the minimal inhibitory concentration (MIC to oxitetracycline in Aeromonas hydrophila strains isolated from marketed fish, pond water of piscicultures and fish suffering hemorrhagic septicemia. These strains were obtained from 12 different piscicultures from Minas Gerais, Rio de Janeiro e Rio Grande do Sul states. It was determined the MIC to 100 strains, using the broth macrodilution method, and the results showed that 86 strains shown value of MIC100µg/mL (classified as resistant. No differences were observed among strains isolated from marketed fish, pond water and disease outbreaks. I was concluded that the variation detected may represent a risk of selection of resistant bacterial strains in aquatic environments under use of oxitetracycline.

Thin-film fixed-bed reactor for solar photocatalytic inactivation of Aeromonas hydrophila: influence of water quality

Directory of Open Access Journals (Sweden)

Khan Sadia J

2012-11-01

Full Text Available Abstract Background Controlling fish disease is one of the major concerns in contemporary aquaculture. The use of antibiotics or chemical disinfection cannot provide a healthy aquaculture system without residual effects. Water quality is also important in determining the success or failure of fish production. Several solar photocatalytic reactors have been used to treat drinking water or waste water without leaving chemical residues. This study has investigated the impact of several key aspects of water quality on the inactivation of the pathogenic bacterium Aeromonas hydrophila using a pilot-scale thin-film fixed-bed reactor (TFFBR system. Results The level of inactivation of Aeromonas hydrophila ATCC 35654 was determined using a TFFBR with a photocatalytic area of 0.47 m2 under the influence of various water quality variables (pH, conductivity, turbidity and colour under high solar irradiance conditions (980–1100 W m-2, at a flow rate of 4.8 L h-1 through the reactor. Bacterial enumeration were obtained through conventional plate count using trypticase soy agar media, cultured in conventional aerobic conditions to detect healthy cells and under ROS-neutralised conditions to detect both healthy and sub-lethally injured (oxygen-sensitive cells. The results showed that turbidity has a major influence on solar photocatalytic inactivation of A. hydrophila. Humic acids appear to decrease TiO2 effectiveness under full sunlight and reduce microbial inactivation. pH in the range 7–9 and salinity both have no major effect on the extent of photoinactivation or sub-lethal injury. Conclusions This study demonstrates the effectiveness of the TFFBR in the inactivation of Aeromonas hydrophila under the influence of several water quality variables at high solar irradiance, providing an opportunity for the application of solar photocatalysis in aquaculture systems, as long as turbidity remains low.

Isolation and Identification of Aeromonas hydrophila and Saprolegnia sp. on Catfish (Clarias gariepinus) in Floating cages in Bozem Moro Krembangan Surabaya

Science.gov (United States)

Kusdarwati, Rahayu; Kismiyati; Sudarno; Kurniawan, Hendi; Teguh Prayogi, Yudha

2017-02-01

Catfish (Clarias gariepinus) is one of the familiar freshwater fish cultured in Indonesia farmer. One of the reason is the high mortality of the catfish infected by Aeromonas hydrophila and Saprolegnia sp. Motile Aeromonas septicemia (MAS) is a common bacterial disease, caused by Aeromonas hydrophila, which affects freshwater fish. In Southeast Asia, the outbreak of this disease was firstly reported from West Java in 1980, when a total of 82.5 tons a month of catfish were lost, while in Central Java in 1984, the total loss was 1.6 tons. Saprolegniosis can cause economic loss due to high mortality from its case reaching 10% to 50%. This research aimed to identify and determine the percentage of A. hydrophila and Saprolegnia sp. the catfish farmed in bozem Moro Krembangan, Surabaya, East Java. Meanwhile, a supporting parameter in this research is the value of water quality parameter including pH, temperature, ammonia and dissolved oxygen that were measured during sampling. The results showed that of the 20 samples taken from the two cages, 19 fish were positively infected by A. drophila. percentage of infections of A. hydrophila that infect umbo catfish in Moro Krembangan, was 95%, while the percentage Saprolegnia sp. was 90%.

Diarrea del viajero asociada a Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

M. Martín Delgado

2001-06-01

Full Text Available Aeromonas hydrophila es una bacteria que se encuentra frecuentemente en aguas dulces y salobres. Desde hace varios años se conoce que determinadas cepas de la especie pueden causar enfermedad en pescados y en anfibios, existiendo cierta controversia sobre su patogeneicidad en humanos. No obstante, puede dar lugar a infección en personas, que la adquieren bien a través de heridas abiertas o bien por ingestión de alimentos o agua contaminados. Sin embargo, en prácticamente la totalidad de las publicaciones se hace referencia a casos aislados más que a brotes producidos por esta bacteria. Generalmente la infección por A. hydrophila da lugar a gastroenteritis en personas sanas, pudiendo generar una septicemia en individuos inmunodeprimidos.En 1998 se produjo una alarma en el sector hotelero por un incremento considerable de los casos de gastroenteritis entre los turistas que acudían durante sus vacaciones a determinadas zonas costeras de la isla de Tenerife.Tras tener conocimiento de la situación, la Dirección General de Salud Pública inició una investigación epidemiológica con el objetivo de conocer la magnitud real del problema detectado e identificar los factores asociados a la misma, para poner en marcha las medidas correctoras y de control necesarias. El análisis inicial permitió determinar que se trataba de un proceso de gran magnitud en su extensión aunque de carácter leve, que afectaba únicamente a los turistas en una zona costera en concreto, compatible por lo tanto con la diarrea del viajero, planteándose un origen probablemente hídrico.

Formação de biofilme em aço inoxidável por Aeromonas hydrophila e Staphylococcus aureus usando leite e diferentes condições de cultivo Biofilm formation by Aeromonas hydrophila and Staphylococcus aureus on stainless steel using milk and different conditions of cultivation

Directory of Open Access Journals (Sweden)

Cleube Andrade Boari

2009-12-01

Full Text Available O objetivo desta pesquisa consistiu em avaliar a formação de biofilme em aço inoxidável por Aeromonas hydrophila e Staphylococcus aureus usando leite e diferentes condições de cultivo. As variáveis em estudo consistem no cultivo monoespécie e combinado, dos referidos microrganismos e nas temperaturas de 4, 7 e 18 °C. Recipientes contendo 1000 mL de leite, densidade populacional de 10(5 UFC.mL-1 de cada microrganismo e 10 cupons de aço inoxidável (10 × 20 mm foram lacrados e armazenados, sob agitação de 60 rpm, por um período de 10 dias. As análises ocorreram a cada 48 horas. Células sésseis de A.hydrophila e S. aureus foram enumeradas através do plaqueamento seletivo em ágar m-Aeromonas selective e Baird-Parker, respectivamente. Estudos sobre o tempo de geração, enumeração de células planctônicas e observação dos cupons através da microscopia eletrônica de varredura foram conduzidos. S. aureus, em monocultivo, formou biofilme a 18 °C e a 7 °C. Para 4 °C, foi observado um processo de adesão. A presença de A. hydrophila reduziu o desempenho de S. aureus. Nesta condição de cultivo multiespécie houve formação de biofilme a 18 °C. A. hydrophila, tanto em monocultivo quanto em presença de S. aureus, formou biofilme em todas as condições pesquisadas.The aim of this research was to verify the capability of biofilm formation on stainless steel by Aeromonas hydrophila and Staphylococcus aureus using milk and different conditions of cultivation. The variables consisted in mono and multi-species cultivation of these microorganisms and in the temperatures of 4, 7 and 18 °C. Containers containing 1000 mL of milk, population density of 10(5 CFU.mL-1 of each microorganism, and ten suspended chips of stainless steel AISI 304 (10 × 20 mm were used to seal up and storage, under 60 rpm of agitation for 10 days. The analyses were conducted every 48 hours. Sessile cells of A. hydrophila and S. aureus and were enumerated

Identification and Characterization of MicroRNAs in the Liver of Blunt Snout Bream (Megalobrama amblycephala Infected by Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

Lei Cui

2016-11-01

Full Text Available MicroRNAs (miRNAs are small RNA molecules that play key roles in regulation of various biological processes. In order to better understand the biological significance of miRNAs in the context of Aeromonas hydrophila infection in Megalobrama amblycephala, small RNA libraries obtained from fish liver at 0 (non-infection, 4, and 24 h post infection (poi were sequenced using Illumina deep sequencing technology. A total of 11,244,207, 9,212,958, and 7,939,157 clean reads were obtained from these three RNA libraries, respectively. Bioinformatics analysis identified 171 conserved miRNAs and 62 putative novel miRNAs. The existence of ten randomly selected novel miRNAs was validated by RT-PCR. Pairwise comparison suggested that 61 and 44 miRNAs were differentially expressed at 4 and 24 h poi, respectively. Furthermore, the expression profiles of nine randomly selected miRNAs were validated by qRT-PCR. MicroRNA target prediction, gene ontology (GO annotation, and Kyoto Encylopedia of Genes and Genomes (KEGG analysis indicated that a variety of biological pathways could be affected by A. hydrophila infection. Additionally, transferrin (TF and transferrin receptor (TFR genes were confirmed to be direct targets of miR-375. These results will expand our knowledge of the role of miRNAs in the immune response of M. amblycephala to A. hydrophila infection, and facilitate the development of effective strategies against A. hydrophila infection in M. amblycephala.

Vaccination in Nile tilapia broodstock with whole cell vaccine and disease resistance in its fry against Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

Sukenda Sukenda

2017-07-01

Full Text Available ABSTRACT The aim of this study was to analyze the effectivity of vaccination in Nile tilapia broodstock with whole cell vaccine and disease resistance in fry tilapia against Aeromonas hydrophila. Tilapia Nirwana strain that used for this had average body weight of 185±13.23 g and were maintained in ponds sizing of (2.5×2.5×1 m3. Vaccinations that has been done through intraperitoneal injection using dose of 0.1 mL/fish, meanwhile the fish for control was injected by phosphate buffered saline (PBS. This study used complete randomized design with two treatments and three replications. Antibody level was measured by using indirect enzyme-linked immunosorbent assay (ELISA method in the broodstock, egg, and fry.  Challenge test in fry tilapia performed at the age of 5, 10, and 15 days. The results showed that vaccination in tilapia broodstock delivered a significant antibody level in broodstock, eggs, and fry (P<0.05 compared to the control. Relative percent survival of offspring at 5, 10, and 15 days were 78.26%, 70.59%, and 65.52%, respectively.  As a conclusion, vaccination in tilapia broodstock was effective to improve specific and non-specific immunity, and protect fry tilapia from A. hydrophila infection through maternal immunity. Keywords: vaccination, antibody, maternal immunity, tilapia, Aeromonas hydrophila  ABSTRAK Penelitian ini bertujuan untuk menganalisis efikasi vaksinasi pada induk nila dengan vaksin sel utuh dan ketahanan benih yang dihasilkan terhadap Aeromonas hydrophila. Ikan nila stain Nirwana yang digunakan dalam penelitian memiliki bobot rata-rata 185±13,23 g dan ikan dipelihara dalam kolam (2,5×2,5×1 m3. vaksinasi dilakukan melalui penyuntikan intraperitoneal dengan dosis 0,1 mL/ikan, sementara itu ikan kontrol disuntik dengan phosphate buffered saline (PBS. Penelitian ini menggunakan rancangan acak lengkap dengan dua perlakuan dan tiga ulangan. Tingkat antibodi diukur dengan menggunakan metode indirect enzyme

A novel recombinant bivalent outer membrane protein of Vibrio vulnificus and Aeromonas hydrophila as a vaccine antigen of American eel (Anguilla rostrata).

Science.gov (United States)

SongLin, Guo; PanPan, Lu; JianJun, Feng; JinPing, Zhao; Peng, Lin; LiHua, Duan

2015-04-01

The immogenicity of a novel vaccine antigen was evaluated after immunized American eels (Anguilla rostrata) with a recombinant bivalent expressed outer membrane protein (OMP) of Vibrio vulnificus and Aeromonas hydrophila. Three groups of eels were intraperitoneal (i.p) injected with phosphate-buffered saline (PBS group), formaline-killed-whole-cell (FKC) of A. hydrophila and V. vulnificus (FKC group) or the bivalent OMP (OMP group). On 14, 21, 28 and 42 days post-vaccination respectively, proliferation of the whole blood cells, titers of specific antibody and lysozyme activities of experimental eels were detected. On 28 day post-vaccination, eels from three groups were challenged by i.p injection of live A. hydrophila or V. vulnificus. The results showed that, compared with the PBS group, proliferation of whole blood cells in OMP group was significant enhanced on 28 days, and the serum titers of anti-A.hydrophila and anti-V. vulnificus antibody in eels of FKC and OMP group were significant increased on 14, 21 and 28d. Lysozyme Activities in serum, skin mucus, liver and kidney were significant changed between the three groups. Relative Percent Survival (RPS) after challenged A. hydrophila in KFC vs. PBS group and OMP vs. PBS group were 62.5% and 50% respectively, and the RPS challenged V. vulnificus in FKC and OMP vs. PBS group were 37.5% and 50% respectively. These results suggest that American eels immunized with the bivalent OMP would positively affect specific as well as non-specific immune parameters and protect against infection by the two pathogens in fresh water farming. Copyright © 2015 Elsevier Ltd. All rights reserved.

Aeromonas hydrophila urinary tract infection in pregnancy- Case report and literature review

Directory of Open Access Journals (Sweden)

Latha Ragunathan

2012-03-01

Full Text Available A case of a pregnant woman without previous or concomitant disease, who developed an Aeromonas hydrophila urinarytract infection (UTI at 12 weeks gestation, is reported. A brief review of the literature on the association and incidenceof Aeromonas spp in urinary infections and also in association with pregnancy is presented. J Microbiol Infect Dis 2012;2(1: 26-28

Effect of dietary supplemented andrographolide on growth, non-specific immune parameters and resistance against Aeromonas hydrophila in Labeo rohita (Hamilton).

Science.gov (United States)

Basha, Kusunur Ahamed; Raman, Ram Prakash; Prasad, Kurcheti Pani; Kumar, Kundan; Nilavan, Ezhil; Kumar, Saurav

2013-11-01

The present study evaluated the effect of dietary andrographolide (EC 50%) on growth, non-specific immune parameters and disease resistance against Aeromonas hydrophila infection in Indian major carp, Labeo rohita fingerlings. Fishes were fed with formulated diet containing andrographolide as T0 (0.00%), T1 (0.05%), T2 (0.10%), T3 (0.20%), T4 (0.40%) and T5 (0.80%) for 42 days. Fishes were challenged with A. hydrophila 42 days post feeding and relative percentage survival (RPS) was recorded over 14 days post challenge. Blood and serum samples were collected for nonspecific immune parameters on 14, 28 and 42 days of feeding and growth performance was evaluated at the end of experiment. The results revealed that fishes fed with andrographolide showed significant (p andrographolide were found to be significantly (p andrographolide at the level of 0.10% showed significantly (P andrographolide supplemented diet has a stimulatory effect on non-specific immune parameters along with improved growth performance and increased disease resistance against A. hydrophila infection in L. rohita fingerlings. Copyright © 2013 Elsevier Ltd. All rights reserved.

Aeromonas hydrophila as cause of hemorrhagic septicemia in a ground-hornbill (Bucorvus abyssinicus).

Science.gov (United States)

Ocholi, R A; Kalejaiye, J O

1990-01-01

An acute hemorrhagic septicemia in a captive ground-hornbill (Bucorvus abyssinicus) is reported. Aeromonas hydrophila was isolated from lungs, liver, kidney, and intestines. Postmortem lesions were characterized by hemorrhages in the internal organs. Microscopically, necrotic lesions were found in the liver, lungs, and kidney. Factors that might have contributed to the clinical disease condition are discussed.

Antibacterial Effect of Gallic Acid against Aeromonas hydrophila and Aeromonas sobria Through Damaging Membrane Integrity.

Science.gov (United States)

Lu, Jing; Wang, Zhenning; Ren, Mengrou; Huang, Guoren; Fang, Baochen; Bu, Xiujuan; Liu, Yanhui; Guan, Shuang

In the study, we investigated the antibacterial activity and mechanism of gallic acid against Aeromonas hydrophila and Aeromonas sobria. Gallic acid showed strong antimicrobial activity against the two bacteria. Furthermore, the antibacterial mechanism of gallic acid (0, 3, 6, 12 mM) was performed by membrane integrity assay and scanning electron microscopy (SEM) assay. The results showed that gallic acid notably increased the released material absorption value at 260, 280 nm and electric conductivity in a dose-dependent manner. Moreover, the SEM assay showed that gallic acid induced severe shrink of bacterial intima and irregular morphology in a dose-dependent manner. The SDS-PAGE profiles further confirmed that gallic acid could damage bacterial cells. These results indicated gallic acid exhibited antibacterial effect by destroying membrane integrity of A. hydrophila and A. sobria. Hence, gallic acid has great potential as a new natural food preservative in food fresh-keeping and storage.

Identification of capsule, biofilm, lateral flagellum, and type IV pili in Vibrio mimicus strains.

Science.gov (United States)

Tercero-Alburo, J J; González-Márquez, H; Bonilla-González, E; Quiñones-Ramírez, E I; Vázquez-Salinas, C

2014-11-01

Vibrio mimicus is a bacterium that causes gastroenteritis; it is closely related to Vibrio cholerae, and can cause acute diarrhea like cholera- or dysentery-type diarrhea. It is distributed worldwide. Factors associated with virulence (such as hemolysins, enterotoxins, proteases, phospholipases, aerobactin, and hemagglutinin) have been identified; however, its pathogenicity mechanism is still unknown. In pathogenic Vibrio species such as V. cholerae, Vibrio. parahaemolyticus and Vibrio vulnificus, capsule, biofilms, lateral flagellum, and type IV pili are structures described as essential for pathogenicity. These structures had not been described in V. mimicus until this work. We used 20 V. mimicus strains isolated from water (6), oyster (9), and fish (5) samples and we were able to identify the capsule, biofilm, lateral flagellum, and type IV pili through phenotypic tests, electron microscopy, PCR, and sequencing. In all tested strains, we observed and identified the presence of capsular exopolysaccharide, biofilm formation in an in vitro model, as well as swarming, multiple flagellation, and pili. In addition, we identified homologous genes to those described in other bacteria of the genus in which these structures have been found. Identification of these structures in V. mimicus is a contribution to the biology of this organism and can help to reveal its pathogenic behavior. Copyright © 2014 Elsevier Ltd. All rights reserved.

EFIKASI RUTE VAKSIN Aeromonas hydrophila ASB-01 PADA IKAN GABUS (Ophiocephalus striatus

Directory of Open Access Journals (Sweden)

Olga Olga

2016-06-01

Full Text Available Penelitian ini bertujuan untuk mengetahui rute pemberian vaksin A.hydrophila ASB-01 yang efektif untuk mengendalikan MAS pada ikan gabus.  Efektivitas rute vaksinasi dievaluasi melalui titer antibodi, sintasan, RPS (relative percent survival dan RWK (Rerata waktu kematian.  Penelitian ini terdiri dari 5 perlakuan (vaksinasi secara rendaman (R, oral (O, injeksi intramuscular (IM, injeksi intraperitoneal (IP dan Kontrol (PBS pH 7,0 dengan  3 ulangan. Dosis vaksinasi sebanyak 107 sel/ml. Vaksinasi booster dilakukan setelah 14 hari kemudian, dosisnya sama dengan vaksinasi awal.  Selanjutnya, 14 hari berikutnya ikan ditantang dengan A.hydrophila ASB-01. Untuk memperoleh data titer antibodi dilakukan pengambilan darah pada saat sebelum divaksinasi, sesaat sebelum vaksinasi booster dan 14 hari setelah vaksinasi booster. Ikan tantang diamati selama 14 hari untuk memperoleh data sintasan, RPS dan RWK. Hasil menunjukkan bahwa semua rute pemberian vaksin dapat meningkatkan titer antibodi, akan tetapi titer antibodi tertinggi diperoleh dari ikan yang divaksinasi secara injeksi.  Sintasan gabus yang divaksinasi secara IM (84,47%, IP (82,20%, R (42,27%, O (42,20% dan kontrol (13,13 %. RPS gabus yang divaksinasi melalui rute IM (82,08%, IP (79,46%, R (33,38%, O (33,31%, sedangkan RWK gabus melalui rute IP (3,63 hari, IM (79,46 3,57 hari, R (2,46 hari, O (1,85 hari dan kontrol (1,03 hari. Rute vaksinasi yang efektif adalah melalui injeksi. This study aims to determine the vaccine A.hydrophila ASB-01 is effective for the control of MAS on snakehead fish. Effectiveness of vaccination was evaluated through the antibody titer, survival, RPS (relative percent survival and RWK (mean time of death. The study consisted of 5 treatments (immersion vaccination (R, oral (O, intramuscular injection (IM, intraperitoneal injection (IP and control (PBS pH 7.0 with 3 replications. Vaccination doses were 107 cells / ml. Booster vaccination after 14 days later. Dose is

Surface protein composition of Aeromonas hydrophila strains virulent for fish: identification of a surface array protein

International Nuclear Information System (INIS)

Dooley, J.S.G.; Trust, T.J.

1988-01-01

The surface protein composition of members of a serogroup of Aeromonas hydrophila was examined. Immunoblotting with antiserum raised against formalinized whole cells of A. hydrophila TF7 showed a 52K S-layer protein to be the major surface protein antigen, and impermeant Sulfo-NHS-Biotin cell surface labeling showed that the 52K S-layer protein was the only protein accessible to the Sulfo-NHS-Biotin label and effectively masked underlying outer membrane (OM) proteins. In its native surface conformation the 52K S-layer protein was only weakly reactive with a lactoperoxidase 125 I surface iodination procedure. A UV-induced rough lipopolysaccharide (LPS) mutant of TF7 was found to produce an intact S layer, but a deep rough LPS mutant was unable to maintain an array on the cell surface and excreted the S-layer protein into the growth medium, indicating that a minimum LPS oligosaccharide size required for A. hydrophila S-layer anchoring. The native S layer was permeable to 125 I in the lactoperoxidase radiolabeling procedure, and two major OM proteins of molecular weights 30,000 and 48,000 were iodinated. The 48K species was a peptidoglycan-associated, transmembrane protein which exhibited heat-modifiable SDS solubilization behavior characteristic of a porin protein. A 50K major peptidoglycan-associated OM protein which was not radiolabeled exhibited similar SDS heat modification characteristics and possibly represents a second porin protein

PROTEKSI VAKSIN MONOVALEN DAN KOKTAIL SEL UTUH TERHADAP KO-INFEKSI Mycobacterium fortuitum DAN Aeromonas hydrophila PADA IKAN GURAME, Osphronemus gouramy Uni

Directory of Open Access Journals (Sweden)

Uni Purwaningsih

2014-08-01

serangan agen patogen. Pemberian vaksin diharapkan dapat merangsang respons imun spesifik dan non spesifik pada ikan. Keberhasilan vaksinasi dipengaruhi oleh konsentrasi antigen, reaksi silang dan kompetisi di antara antigen yang berbeda. Penelitian ini bertujuan untuk menganalisis level proteksi vaksin monovalen dan koktail sel utuh terhadap ko-infeksi M. fortuitum dan A. hydrophila pada ikan gurame. Respons imun perlakuan vaksin monovalen maupun koktail pada gurame pasca ko-infeksi menunjukkan nilai parameter-parameter yaitu: hematokrit, hemoglobin, indeks fagositik, persentase fagositik, titer antibodi, uji respiratory burst (NBT, aktivitas komplemen, dan diferensial leukosit yang berbeda nyata (P<0,05 dibanding kontrol. Vaksin monovalen A. hydrophila menunjukkan nilai RPS sebesar 92,3% dan monovalen M. fortuitum sebesar 78,6% setelah ditantang dengan infeksi tunggal bakteri homolog namun menunjukkan proteksi yang rendah terhadap ko-infeksi. Vaksin koktail 50Mf :50Ah memberikan proteksi yang lebih baik dari vaksin monovalen pasca uji tantang dengan ko-infeksi bakteri M. fortuitum dan A. hydrophila.

A foodborne outbreak of Aeromonas hydrophila in a college, Xingyi City, Guizhou, China, 2012.

Science.gov (United States)

Zhang, Qian; Shi, Guo-Qing; Tang, Guang-Peng; Zou, Zhi-Tin; Yao, Guang-Hai; Zeng, Guang

2012-10-01

On 12 May 2012, over 200 college students with acute diarrhoea were reported to the Guizhou Center for Disease Control and Prevention. We conducted an investigation to identify the agent and mode of transmission and to recommend control measures. A suspected case was a person at the college with onset of ≥ two of the following symptoms: diarrhoea (more than three loose stools in 24 hours), abdominal pain, vomiting or fever (> 37.5C) between 6 and 15 May 2012. A confirmed case also had a positive Aeromonas hydrophila culture from a stool sample. A retrospective-cohort study of 902 students compared attack rates (AR) by dining place, meals and food history. We reviewed the implicated premise, its processes and preparation of implicated food. We identified 349 suspected cases (AR = 14%) and isolated Aeromonas hydrophila from three stools of 15 cases. Students who ate in cafeteria A were more likely to be ill compared to those eating in other places (relative risk [RR]: 3.1, 95% confidence interval [CI]: 2.0-4.8). The cohort study implicated cold cucumber (RR: 2.6, 95% CI: 2.0-3.3) and houttuynia dishes (RR: 1.8, 95% CI: 1.4-2.3). Environmental investigation showed that vegetables were washed in polluted water from a tank close to the sewage ditch, then left at 30 °C for two hours before serving. The Escherichia coli count of the tank was well above the standard for drinking-water. This outbreak of Aeromonas hydrophila was most probably caused by salad ingredients washed in contaminated tank water. We recommended enhancing training of foodhandlers, ensuring tanks and sewerage systems comply with appropriate standards and adequate monitoring of drinking-water sources.

A foodborne outbreak of Aeromonas hydrophila in a college, Xingyi City, Guizhou, China, 2012

Directory of Open Access Journals (Sweden)

Guang Zeng

2012-12-01

Full Text Available Background: On 12 May 2012, over 200 college students with acute diarrhoea were reported to the Guizhou Center for Disease Control and Prevention. We conducted an investigation to identify the agent and mode of transmission and to recommend control measures.Methods: A suspected case was a person at the college with onset of more than two of the following symptoms: diarrhoea (more than three loose stools in 24 hours, abdominal pain, vomiting or fever (> 37.5C between 6 and 15 May 2012. A confirmed case also had a positive Aeromonas hydrophila culture from a stool sample. A retrospective-cohort study of 902 students compared attack rates (AR by dining place, meals and food history. We reviewed the implicated premise, its processes and preparation of implicated food.Results: We identified 349 suspected cases (AR = 14% and isolated Aeromonas hydrophila from three stools of 15 cases. Students who ate in cafeteria A were more likely to be ill compared to those eating in other places (relative risk [RR]: 3.1, 95% confidence interval [CI]: 2.0–4.8. The cohort study implicated cold cucumber (RR: 2.6, 95% CI: 2.0–3.3 and houttuynia dishes (RR: 1.8, 95% CI: 1.4–2.3. Environmental investigation showed that vegetables were washed in polluted water from a tank close to the sewage ditch, then left at 30°C for two hours before serving. The Escherichia coli count of the tank was well above the standard for drinking water.Conclusion: This outbreak of Aeromonas hydrophila was most probably caused by salad ingredients washed in contaminated tank water. We recommended enhancing training of foodhandlers, ensuring tanks and sewerage systems comply with appropriate standards and adequate monitoring of drinking water sources.

Comparison of efficacies of bovine immune colostral antibody and each immunoglobulin class against verotoxin 2, flagellum and somatic cells of Escherichia coli O157:H7 in mice.

Science.gov (United States)

Seita, Tetsurou; Kuribayashi, Takashi; Honjo, Toshio; Yamamoto, Shizuo

2013-04-01

The efficacy of bovine immune colostral (colostral) antibodies against verotoxin (VT) 2, flagellum and somatic cells of Escherichia coli (E. coli) O157:H7 in mice was determined. Three major immunoglobulin (Ig) classes were isolated from the colostral antibody against VT2 by affinity chromatography and were used for estimation. Mice inoculated with VT2 were administered each Ig class from the colostral antibody, colostral antibody (colostral whey containing antibody) or serum antibody against VT2 at 1 hour after VT2 inoculation. All control mice (20/20) died after administration of sterilized saline instead of the colostral antibody. The survival rate was 93.3% (14/15) after administration of S-IgA or IgM antibody, or colostral antibody. Survival rates for IgG antibody and serum antibody administration were 80% (12/15) and 60% (9/15), respectively. Serum concentrations of VT2, which was absorbed from the small intestine in mice after administration of VT2 and colostral antibody, were measured by fluorescence enzyme immunoassay (FEIA). Serum concentrations of VT2 after administration of colostral antibody were lower than those after administration of sterilized saline. Mice inoculated with VT2-producing E. coli 157:H7 were administered anti-flagellum or anti-somatic colostral antibodies. Survival rates for E. coli O157:H7-infected mice administered the anti-flagellum and anti-somatic colostral antibodies were 52.4% (11/21) and 22.2% (4/18), respectively. Furthermore, survival rates increased to 89.5% (17/19) with combined administration of anti-flagellum and anti-VT2 colostral antibodies. These results suggest that colostral antibodies against VT2, flagellum and somatic cells are effective against E. coli O157:H7 infection. Copyright © 2012. Published by Elsevier B.V.

Evaluation of traditional plant extracts for innate immune mechanisms and disease resistance against fish bacterial Aeromonas hydrophila and Pseudomonas sp.

Science.gov (United States)

Hardi, E. H.; Saptiani, G.; Kusuma, I. W.; Suwinarti, W.; Nugroho, R. A.

2018-03-01

The purposes of this study were to evaluate effect of ethanol herbal extracts of Boesenbergia pandurata, Solanum ferox and Zingimber zerumbet on Tilapia (Oreochromis nilaticus) innate immune mechanisms and disease resistance against Aeromonas hydrophila and Pseudomonas sp. Fish were intramuscularly injected with 0.1 mL/fish (1010 CFU mL-1) of each bacterium on the day 6th of post treatment using extract by several methods (injection, oral administration and immersion). The doses of extract were 600 ppm of B. pandurata, 900 ppm S. ferox and 200 ppm of Z. zerumbet. The percentage mortality, Relative Percent Survival (RPS) and innate immune response were assessed on weeks 1, 2, 3 and 4. All the methods were effective to enhance the immune parameters after 2 weeks application and the RPS of treatment reached more than 90 %. The results showed that the injection method of extracts was the most effective method to control A. hydrophila and Pseudomonas sp. The result indicated that all the doses of extracts could be significantly influence the immune response and protect the health status of tilapia against A. hydrophila and Pseudomonas sp. infections.

Aminoglycoside-resistant Aeromonas hydrophila as part of a polymicrobial infection following a traumatic fall into freshwater.

Science.gov (United States)

Shak, Joshua R; Whitaker, Jennifer A; Ribner, Bruce S; Burd, Eileen M

2011-03-01

Amikacin is a first-line treatment for Aeromonas infection due to high efficacy. There are few reports of aminoglycoside-resistant Aeromonas spp. We report a soft tissue infection containing multiple pathogens, including a strain of Aeromonas hydrophila resistant to amikacin, tobramycin, and multiple cephalosporins.

FliO Regulation of FliP in the Formation of the Salmonella enterica Flagellum

OpenAIRE

Barker, Clive S.; Meshcheryakova, Irina V.; Kostyukova, Alla S.; Samatey, Fadel A.

2010-01-01

The type III secretion system of the Salmonella flagellum consists of 6 integral membrane proteins: FlhA, FlhB, FliO, FliP, FliQ, and FliR. However, in some other type III secretion systems, a homologue of FliO is apparently absent, suggesting it has a specialized role. Deleting the fliO gene from the chromosome of a motile strain of Salmonella resulted in a drastic decrease of motility. Incubation of the ΔfliO mutant strain in motility agar, gave rise to pseudorevertants containing extrageni...

Multiple drug resistance of Aeromonas hydrophila isolates from Chicken samples collected from Mhow and Indore city of Madhyapradesh

Directory of Open Access Journals (Sweden)

Kaskhedikar

2009-02-01

Full Text Available Fourteen antibacterial agents belonging to 9 different groups of antibiotics viz. aminoglycosides, cephalosporins, nitrofurantoin, fluroquinolones, chloramphenicol, sulphonamides, tetracyclines, penicillin and polymixin were used for in vitro sensitivity testing of Aeromonas hydrophila isolated from fifteen samples of chicken collected from retail shops in Mhow city. The sensitivity (100% was attributed to ciprofloxacin, cefuroxime, ceftriaxone, cephotaxime, chloramphenicol, gentamycin, kanamycin, nitrofurantoin, nalidixic acid and ofloxacin followed by oxytetracycline (50%. All the isolates were resistant to ampicillin and colistin antibiotics. That means, none of the isolates were found to be sensitive for penicillin and polymixin group of antibiotics. Multiple drug resistance was also observed in all A. hydrophila isolates. Out of total isolates, 100% were resistant to two antimicrobial drugs and 50% to three drugs. [Vet. World 2009; 2(1.000: 31-32

Transcriptome differences between enrofloxacin-resistant and enrofloxacin-susceptible strains of Aeromonas hydrophila

OpenAIRE

Zhu, Fengjiao; Yang, Zongying; Zhang, Yiliu; Hu, Kun; Fang, Wenhong

2017-01-01

Enrofloxacin is the most commonly used antibiotic to control diseases in aquatic animals caused by A. hydrophila. This study conducted de novo transcriptome sequencing and compared the global transcriptomes of enrofloxacin-resistant and enrofloxacin-susceptible strains. We got a total of 4,714 unigenes were assembled. Of these, 4,122 were annotated. A total of 3,280 unigenes were assigned to GO, 3,388 unigenes were classified into Cluster of Orthologous Groups of proteins (COG) using BLAST an...

Aminoglycoside-Resistant Aeromonas hydrophila as Part of a Polymicrobial Infection following a Traumatic Fall into Freshwater▿

Science.gov (United States)

Shak, Joshua R.; Whitaker, Jennifer A.; Ribner, Bruce S.; Burd, Eileen M.

2011-01-01

Amikacin is a first-line treatment for Aeromonas infection due to high efficacy. There are few reports of aminoglycoside-resistant Aeromonas spp. We report a soft tissue infection containing multiple pathogens, including a strain of Aeromonas hydrophila resistant to amikacin, tobramycin, and multiple cephalosporins. PMID:21209173

Isolation of bacterial fish pathogen Aeromonas hydrophila and therapeutic effects of medicinal plants on its invasion

Directory of Open Access Journals (Sweden)

Md. Tareq-Uz-Zaman

2014-04-01

Full Text Available Aeromonas hydrophila, a bacterial pathogen, was isolated form Pangasius hypophthalmus. For pathogenicity test, different doses were injected intramuscularly in Barbonymus gonionotus. Crude extracts were prepared from various parts Azadirachta indica, Curcuma longa, C. zedoaria, and Callotropis gigentia and applied to B. gonionotus for 7 days. Bath treatment was done up to their tolerance level and well ventilation was confirmed for aeration and 50% water was exchanged daily. Minimum inhibitory dose was detected as 7 mg/ml. High inhibitory effect was observed in case of A. indica and mixed extract of A. indica and C. gigentia. Both A. indica and C. gigentia showed the best result with 90-95% recovery of infected fish at a dose of 7 mg/l. C. zedoaria showed moderate to weak effect with 50-60% recovery at the same dose. The present study showed that medicinal plants would be an effective control measure against A. hydrophila.

Necrotizing Fasciitis Caused by Inconspicuous Infection of Aeromonas hydrophila in an Immunocompromised Host

Directory of Open Access Journals (Sweden)

Kuo-Chun Liao

2010-09-01

Full Text Available We present a case of serious necrotizing fasciitis due to Aeromonas hydrophila without a suggestive history of routes of pathogen invasion in a 60-year-old male. Despite prompt broad-spectrum antibiotic and extensive surgical therapies, the patient died within 72 hours following initial presentation. Our experience suggests clinicians be highly alert to the disease when an immunocompromised patient featured fulminant soft-tissue infection in the endemic area.

Detection of Aeromonas hydrophila DNA oligonucleotide sequence using a biosensor design based on Ceria nanoparticles decorated reduced graphene oxide and Fast Fourier transform square wave voltammetry

International Nuclear Information System (INIS)

Jafari, Safiye; Faridbod, Farnoush; Norouzi, Parviz; Dezfuli, Amin Shiralizadeh; Ajloo, Davood; Mohammadipanah, Fatemeh; Ganjali, Mohammad Reza

2015-01-01

A new strategy was introduced for ssDNA immobilization on a modified glassy carbon electrode. The electrode surface was modified using polyaniline and chemically reduced graphene oxide decorated cerium oxide nanoparticles (CeO_2NPs-RGO). A single-stranded DNA (ssDNA) probe was immobilized on the modified electrode surface. Fast Fourier transform square wave voltammetry (FFT-SWV) was applied as detection technique and [Ru(bpy)_3]"2"+"/"3"+ redox signal was used as electrochemical marker. The hybridization of ssDNA with its complementary target caused a dramatic decrease in [Ru(bpy)_3]"2"+"/"3"+ FFT-SW signal. The proposed electrochemical biosensor was able to detect Aeromonas hydrophila DNA oligonucleotide sequence encoding aerolysin protein. Under optimal conditions, the biosensor showed excellent selectivity toward complementary sequence in comparison with noncomplementary and two-base mismatch sequences. The dynamic linear range of this electrochemical DNA biosensor for detecting 20-mer oligonucleotide sequence of A. hydrophila was from 1 × 10"−"1"5 to 1 × 10"−"8 mol L"−"1. The proposed biosensor was successfully applied for the detection of DNA extracted from A. hydrophila in fish pond water up to 0.01 μg mL"−"1 with RSD of 5%. Besides, molecular docking was applied to consider the [Ru(bpy)_3]"2"+"/"3"+ interaction with ssDNA before and after hybridization. - Highlights: • New DNA biosensor is designed for sub-femtomolar detection of Aeromonas hydrophila DNA sequence. • Reduced graphene oxide decorated Ceria nanoparticles was used as a new immobilization platform. • Biosensor was successfully used to detect A. hydrophila DNA sequence in fish pond water.

Antibiotic resistence of Aeromonas hydrophila isolated from Piaractus mesopotamicus (Holmberg, 1887 and Oreochromis niloticus (Linnaeus, 1758 Resistência de Aeromonas hydrophila isolada de Piaractus mesopotamicus (Holmberg, 1887 e Oreochromis niloticus (Linnaeus, 1758 a antibióticos

Directory of Open Access Journals (Sweden)

Andréa Belém-Costa

2006-06-01

Full Text Available One of the most important problems involving treatments with antibiotics against Aeromonas hydrophila isolated from fishes is that antibiotic resistance develops readily. The antimicrobial activity of chemotherapeutants in isolates from pacu Piaractus mesopotamicus (Holmberg, 1887 and tilapia Oreochromis niloticus (Linnaeus, 1758 was tested by the Kirby-Bauer disk method, over Mueller-Hinton surface agar previously inoculated with 100 µL of bacterial suspensions. After regular incubation, isolates from tilapia and pacu were uniformly resistant to amoxicillin, ampicillin, lincomycin, novobiocin, oxacillin, penicillin, and trimetoprim+sulfametoxazole. The A. hydrophila type strain presented resistance to the same antimicrobial substances and also against rifampicin; the bacterial isolate from pacu were the only strain resistant to tetracyclin. Isolates from both pacu and tilapia had intermediate reaction with erytromycin. The use of drugs in commercial fish farms in Brazil can favor the development of resistant bacterial strains in native fish species as already observed for exotic species, commercially produced for longer time.Um dos maiores problemas envolvendo o tratamento com antibióticos contra Aeromonas hydrophila isolada de peixes confinados é a rápida resistência ao antibiótico desenvolvida pela bactéria. A atividade antimicrobiana de quimioterapêuticos em isolados a partir de pacu Piaractus mesopotamicus (Holmberg, 1887 e tilápia Oreochromis niloticus (Linnaeus, 1758 foi verificada pelo método de difusão de antibiótico em discos de Kirby-Bauer, sobre uma superfície de Agar Mueller-Hinton previamente inoculada com 100 µL de suspensão bacteriana. Após o período de incubação, os isolados de tilápia e pacu foram uniformemente resistentes a amoxicilina, ampicilina, lincomicina, novobiocina, oxacilina, penicilina e trimetoprim+sulfametoxazol. A cepa tipo para A. hydrophila apresentou resistência às mesmas subst

Detection of Aeromonas hydrophila DNA oligonucleotide sequence using a biosensor design based on Ceria nanoparticles decorated reduced graphene oxide and Fast Fourier transform square wave voltammetry

Energy Technology Data Exchange (ETDEWEB)

Jafari, Safiye [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Faridbod, Farnoush, E-mail: faridbodf@khayam.ut.ac.ir [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Biosensor Research Center, Endocrinology & Metabolism Molecular and Cellular Research Institute, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Norouzi, Parviz [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Biosensor Research Center, Endocrinology & Metabolism Molecular and Cellular Research Institute, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Dezfuli, Amin Shiralizadeh [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Ajloo, Davood [School of Chemistry, Damghan University, Damghan (Iran, Islamic Republic of); Mohammadipanah, Fatemeh [Department of Microbial Biotechnology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, 14155-6455 Tehran (Iran, Islamic Republic of); Ganjali, Mohammad Reza [Center of Excellence in Electrochemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Biosensor Research Center, Endocrinology & Metabolism Molecular and Cellular Research Institute, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

2015-10-01

A new strategy was introduced for ssDNA immobilization on a modified glassy carbon electrode. The electrode surface was modified using polyaniline and chemically reduced graphene oxide decorated cerium oxide nanoparticles (CeO{sub 2}NPs-RGO). A single-stranded DNA (ssDNA) probe was immobilized on the modified electrode surface. Fast Fourier transform square wave voltammetry (FFT-SWV) was applied as detection technique and [Ru(bpy){sub 3}]{sup 2+/3+} redox signal was used as electrochemical marker. The hybridization of ssDNA with its complementary target caused a dramatic decrease in [Ru(bpy){sub 3}]{sup 2+/3+} FFT-SW signal. The proposed electrochemical biosensor was able to detect Aeromonas hydrophila DNA oligonucleotide sequence encoding aerolysin protein. Under optimal conditions, the biosensor showed excellent selectivity toward complementary sequence in comparison with noncomplementary and two-base mismatch sequences. The dynamic linear range of this electrochemical DNA biosensor for detecting 20-mer oligonucleotide sequence of A. hydrophila was from 1 × 10{sup −15} to 1 × 10{sup −8} mol L{sup −1}. The proposed biosensor was successfully applied for the detection of DNA extracted from A. hydrophila in fish pond water up to 0.01 μg mL{sup −1} with RSD of 5%. Besides, molecular docking was applied to consider the [Ru(bpy){sub 3}]{sup 2+/3+} interaction with ssDNA before and after hybridization. - Highlights: • New DNA biosensor is designed for sub-femtomolar detection of Aeromonas hydrophila DNA sequence. • Reduced graphene oxide decorated Ceria nanoparticles was used as a new immobilization platform. • Biosensor was successfully used to detect A. hydrophila DNA sequence in fish pond water.

Draft genome sequence of Pseudomonas mosselii Gil3, isolated from catfish and antagonistic against hypervirulent Aeromonas hydrophila

Science.gov (United States)

Pseudomonas mosselii Gil3 was isolated from a catfish that survived from lethal challenge with hypervirulent Aeromonas hydrophila (vAh). When assayed in vitro, the bacterium showed antagonism against vAh. Sequence analysis revealed that the genome of P. mosselii Gil3 encodes numerous aromatic metabo...

Histopathology of red-sore disease (aeromonas hydrophila) in naturally and experimentally infected largemouth bass micropterus salmoides(lacepede)

Energy Technology Data Exchange (ETDEWEB)

Huizinga, H W [Illinois State Univ., Normal; Esch, G W; Hazen, T C

1979-01-01

The histopathology of red-sore disease, caused by the gram-negative bacterium, Aeromonas hydrophila, is described for largemouth bass, Micropterus salmoides. Externally, lesions range from those affecting a few scales (pin-point), to those associated with extensive chronic ulcerations; there is focal hemorrhage, oedema and dermal necrosis which exposes underlying muscles producing infiltration of mononuclear and granulocytic inflammatory cells. Internally, the liver and kidneys are foci for toxic products produced by A. hydrophila with, in the most severe cases, complete destruction of the structural integrity of both organs. Pathological changes were not serious in either the spleen or heart, even in cases with massive damage in the liver and kidney. Internal and external lesions were similar in both natural and experimentally induced infections. The pathobiology of red-sore disease in bass was postulated to be linked to elevated water temperature stimulating increased metabolism, decreased body condition and stress, leading to the increased production of corticosteroids and the concommitant rise in susceptibility to infection.

CARACTERIZACIÓN Y EVALUACIÓN in vivo E in vitro DEL LIPOPOLISACÁRIDO DE Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

A P JIMENEZ

2008-05-01

Full Text Available A partir de una cepa de A. hydrophila aislada de un brote de enfermedad septicémica en Tilapia nilótica (Piaractus brachypomusoreochromis niloticus, se obtuvieron extractos de lipopolisacárido (LPS crudo (29,5 mg/ml y semipurificado (106,5 mg/ml mediante la técnica fenol-agua caliente descrita por Westphal, Jann (1965. La presencia de proteína fue del 2,3% para el extracto crudo y de 0,1% para el semipurificado; la concentración de polisacáridos osciló entre el 15 y 26%. En electroforesis (SDS-PAGE se observaron bandas de 14 Kd correspondientes al oligosacárido central y al lípido A del LPS. Tres ratones de 25-35 g fueron inoculados intraperitonealmente con 25 mg/Kg de LPS cru-do, a partir de la primera hora todos los animales mostraron erizamiento, taquipnea e inapetencia; microscópicamente se detectó congestión hepática y pulmonar, hemorragias pulmonares y renales, marginación leucocitaria en hígado y pulmón con predominio de polimorfo-nucleares neutrófilos (PMN en todos los animales, mostrando un mayor efecto que el control inoculado con LPS de E. coli (Sigma® a la misma concentración. In vitro el LPS crudo a concentración de 10, 20 y 30 µg/ml indujo proliferación de células mono-nucleares murinas (2 x 10 5 en 200 µl de medio DMEM por incorporación de timidina tritiada; tanto el LPS control (E. coli, como el LPS crudo de A. hydrophila mostraron cuentas por minuto (CPM ascendentes de manera dosis dependiente, el LPS de A. hydrophila desencadeno una proliferación muy similar a la inducida por el control.

Eficácia do florfenicol e da oxitetraciclina no controle de Aeromonas hydrophila em pacu (Piaractus mesopotamicus

Directory of Open Access Journals (Sweden)

S.P. Carraschi

2011-06-01

Full Text Available Determinou-se a concentração eficaz de oxitetraciclina (OTC e florfenicol (FFC no tratamento de Aeromonas hydrophila em pacu (Piaractus. mesopotamicus. Os pacus foram submetidos à captura duas vezes ao dia por quatro dias e em seguida foram infectados com A. hydrophila (2,4x10(7 bactéria mL-1. Os tratamentos utilizados foram: controle sem infecção (CSI, controle com infecção (CCI e tratados com 110,0; 140,0 e 170,0mgOTC.kg-1, e 5,0; 10,0 e 15,0mgFFC.kg-1. As variáveis de qualidade da água foram monitoradas diariamente. Após o tratamento, no CSI dos dois testes, ocorreu 100% de sobrevivência. Nos testes com OTC, no CCI, a sobrevivência foi de 29,2%; em 110,0mg.kg-1, 37,5%; em 140,0mg.kg-1, 29,2%; e em 170,0mg.kg-1, 50,0%. Nos testes com FFC, foi eficaz com 10,0mg.kg-1, e no CCI a sobrevivência foi de 76,9%; em 5,0mg.kg-1, 81,81%; em 10,0mg/L.kg-1, 100% e em 15,0mg.kg-1, 87,5%. A OTC, em concentrações de até 170,0mg.kg-1 de ração, não é eficaz para o controle de A. hydrophila em pacu, e o FFC é eficaz na concentração de 10,0mg.kg-1 e ambos não alteram as variáveis de qualidade de água.

Molecular detection of Aeromonas hydrophila in the aquarium gold fish and cultured rainbow trout in Chaharmahal va Bakhtiary province

Directory of Open Access Journals (Sweden)

firouz Fadaeifard

2014-05-01

Full Text Available Aeromonas hydrophilia   is the etiologic agent of motile aeromonas septicaemia, one of the most important bacterial diseases of fresh and marine water fishes. The aim of the present study was detection of A. hydrophilia in the aquarium goldfish and cultured rainbow trout in Chaharmahal va Bakhtiary province.  In this study 50 goldfish from aquarium fish shops and 60 rainbow trouts suspected of having the disease from 6 farms (10 fish in each farm were randomly collected. The average weight in goldfish and rainbow trout samples were 3-5 g and 10-20 g, respectively. Sampling was performed from kidney and liver, and inoculated into blood agar and incubated at 22°C for 24 hours. Pure colonies which are grown on the mediums were tested by catalase, oxidase and gram staining, then those of gram-negative, catalase and oxidase positive were diagnosed, and cultured on Shotts-Rimler medium (as selective medium for A. hydrophila. These mediums were incubated at 22 °C for 24-48 h. The typical colonies were tested by using oligonucleotide primers of lip gene by PCR method. In light of molecular analysis of all specimens, 9 and 6 isolates from rainbow trout and gold fishes were identified as A. hydrophila respectively. Due to the detection of A. hydrophila in both cultured rainbow trout and aquarium goldfish, the bacteria can lead to septicemia with mortality if the health management principles are not observed in fish farming.

Molecular cloning of Japanese eel Anguilla japonica TNF-α and characterization of its expression in response to LPS, poly I:C and Aeromonas hydrophila infection

Science.gov (United States)

Feng, Jianjun; Guan, Ruizhang; Guo, Songlin; Lin, Peng; Zadlock, Frank

2014-09-01

As a potent pleiotropic cytokine, tumor necrosis factor-alpha (TNF-α) plays an important role in innate immune responses. The cDNA sequence and genomic structure of the TNF-α gene ( Aj TNF-α) in the Japanese eel ( Anguilla japonica) were identified and characterized. The full-length AjTNF-α cDNA was 1 546 bp, including a 5'-untranslated region (UTR) of 13 bp, a 3'-UTR of 879 bp and an open reading frame of 654 bp encoding a protein of 218 amino acids. The full-length genomic sequence of AjTNF-α was 2 392 bp and included four exons and three introns. The putative AjTNF-α protein contained TNF family signature motifs, including a protease cleavage site, a transmembrane domain and two conserved cysteine residues. Quantitative real-time reverse transcription PCR analysis revealed AjTNF-α expression in a wide range of tissues, with predominant expression in blood and liver. Lower levels of expression were seen in spleen, gills, kidney, intestine, heart, and skin, with very low levels in muscle. The modulation of AjTNF-α expression after injection of eels with lipopolysaccharide (LPS), the viral mimic, poly I:C, or Aeromonas hydrophila was assessed in blood, liver, and kidney. In blood, TNF-α mRNA levels increased rapidly and then rapidly decreased after stimulation with LPS, poly I:C or A. hydrophila. However, the response to LPS and A. hydrophila peaked at 6 h while for poly I:C the peak was at 12 h. In liver, after injection with A. hydrophila, an up- and down-regulation of AjTNF-α expression occurred twice, peaking at 6 h and 24 h, respectively. No remarkable increase of AjTNF-α expression appeared in liver until 72 h after LPS or poly I:C treatment. In kidney, AjTNF-α expression increased significantly only at 72 h post-stimulation with LPS or A. hydrophila. Our results suggest that AjTNF-α plays an important role in fish in the defense against viral and bacterial infection.

Modulation of flagellum attachment zone protein FLAM3 and regulation of the cell shape in Trypanosoma brucei life cycle transitions

Czech Academy of Sciences Publication Activity Database

Sunter, J.C.; Benz, C.; Andre, L.; Whipple, S.; McKean, P.G.; Gull, K.; Ginger, M. L.; Lukeš, Julius

2015-01-01

Roč. 128, č. 16 (2015), s. 3117-3130 ISSN 0021-9533 R&D Projects: GA MŠk(CZ) EE2.3.30.0032; GA MŠk LH12104 EU Projects: European Commission(XE) 316304 Institutional support: RVO:60077344 Keywords : Trypanosomes * Morphogenesis * Flagellum attachment zone Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.706, year: 2015

Thin-film fixed-bed reactor (TFFBR for solar photocatalytic inactivation of aquaculture pathogen Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

Khan Sadia J

2012-01-01

Full Text Available Abstract Background Outbreaks of infectious diseases by microbial pathogens can cause substantial losses of stock in aquaculture systems. There are several ways to eliminate these pathogens including the use of antibiotics, biocides and conventional disinfectants, but these leave undesirable chemical residues. Conversely, using sunlight for disinfection has the advantage of leaving no chemical residue and is particularly suited to countries with sunny climates. Titanium dioxide (TiO2 is a photocatalyst that increases the effectiveness of solar disinfection. In recent years, several different types of solar photocatalytic reactors coated with TiO2 have been developed for waste water and drinking water treatment. In this study a thin-film fixed-bed reactor (TFFBR, designed as a sloping flat plate reactor coated with P25 DEGUSSA TiO2, was used. Results The level of inactivation of the aquaculture pathogen Aeromonas hydrophila ATCC 35654 was determined after travelling across the TFFBR under various natural sunlight conditions (300-1200 W m-2, at 3 different flow rates (4.8, 8.4 and 16.8 L h-1. Bacterial numbers were determined by conventional plate counting using selective agar media, cultured (i under conventional aerobic conditions to detect healthy cells and (ii under conditions designed to neutralise reactive oxygen species (agar medium supplemented with the peroxide scavenger sodium pyruvate at 0.05% w/v, incubated under anaerobic conditions, to detect both healthy and sub-lethally injured (oxygen-sensitive cells. The results clearly demonstrate that high sunlight intensities (≥ 600 W m-2 and low flow rates (4.8 L h-1 provided optimum conditions for inactivation of A. hydrophila ATCC 3564, with greater overall inactivation and fewer sub-lethally injured cells than at low sunlight intensities or high flow rates. Low sunlight intensities resulted in reduced overall inactivation and greater sub-lethal injury at all flow rates. Conclusions This

The non-flagellar type III secretion system evolved from the bacterial flagellum and diversified into host-cell adapted systems.

Directory of Open Access Journals (Sweden)

Sophie S Abby

2012-09-01

Full Text Available Type 3 secretion systems (T3SSs are essential components of two complex bacterial machineries: the flagellum, which drives cell motility, and the non-flagellar T3SS (NF-T3SS, which delivers effectors into eukaryotic cells. Yet the origin, specialization, and diversification of these machineries remained unclear. We developed computational tools to identify homologous components of the two systems and to discriminate between them. Our analysis of >1,000 genomes identified 921 T3SSs, including 222 NF-T3SSs. Phylogenomic and comparative analyses of these systems argue that the NF-T3SS arose from an exaptation of the flagellum, i.e. the recruitment of part of the flagellum structure for the evolution of the new protein delivery function. This reconstructed chronology of the exaptation process proceeded in at least two steps. An intermediate ancestral form of NF-T3SS, whose descendants still exist in Myxococcales, lacked elements that are essential for motility and included a subset of NF-T3SS features. We argue that this ancestral version was involved in protein translocation. A second major step in the evolution of NF-T3SSs occurred via recruitment of secretins to the NF-T3SS, an event that occurred at least three times from different systems. In rhizobiales, a partial homologous gene replacement of the secretin resulted in two genes of complementary function. Acquisition of a secretin was followed by the rapid adaptation of the resulting NF-T3SSs to multiple, distinct eukaryotic cell envelopes where they became key in parasitic and mutualistic associations between prokaryotes and eukaryotes. Our work elucidates major steps of the evolutionary scenario leading to extant NF-T3SSs. It demonstrates how molecular evolution can convert one complex molecular machine into a second, equally complex machine by successive deletions, innovations, and recruitment from other molecular systems.

In vitro comparisons of the inhibitory activity of florfenicol copper sulfate and potassium permanganate towards Aeromonas hydrophila and Flavobacterium columnare

Science.gov (United States)

Aeromonas hydrophila and Flavobacterium columnare, the etiological agents of motile aeromonas septicemia (MAS) and columnaris disease, respectively, have been recently causing crippling moralities to the sunshine bass, Morone chrysops female X Morone saxatilis male (Percichthyidae), industry in the ...

A DNA biosensor for molecular diagnosis of Aeromonas hydrophila using zinc sulfide nanospheres

Directory of Open Access Journals (Sweden)

M. Negahdary

2017-07-01

Full Text Available Today, identification of pathogenic bacteria using modern and accurate methods is inevitable. Integration in electrochemical measurements with nanotechnology has led to the design of efficient and sensitive DNA biosensors against bacterial agents. Here, efforts were made to detect Aeromonas hydrophila using aptamers as probes and zinc sulfide (ZnS nanospheres as signal enhancers and electron transfer facilitators. After modification of the working electrode area (in a screen-printed electrode with ZnS nanospheres through electrodeposition, the coated surface of a modified electrode with ZnS nanospheres was investigated through scanning electron microscopy (SEM. The size of synthesized ZnS nanospheres was estimated at about 20–50 nm and their shape was in the form of porous plates in microscopic observations. All electrochemical measurements were performed using cyclic voltammetry (CV, electrochemical impedance spectroscopy (EIS, and constant potential amperometry (CPA techniques. The designed DNA biosensor was able to detect deoxyribonucleic acid (DNA of Aeromonas hydrophila in the range 1.0  ×  10−4 to 1.0  ×  10−9 mol L−1; the limit of detection (LOD in this study was 1  ×  10−13 mol L−1. This DNA biosensor showed satisfactory thermal and pH stability. Reproducibility for this DNA biosensor was measured and the relative standard deviation (RSD of the performance of this DNA biosensor was calculated as 5 % during 42 days.

Antibiotic resistence of Aeromonas hydrophila isolated from Piaractus mesopotamicus (Holmberg, 1887) and Oreochromis niloticus (Linnaeus, 1758)

OpenAIRE

Belém-Costa,Andréa; Cyrino,José Eurico Possebon

2006-01-01

One of the most important problems involving treatments with antibiotics against Aeromonas hydrophila isolated from fishes is that antibiotic resistance develops readily. The antimicrobial activity of chemotherapeutants in isolates from pacu Piaractus mesopotamicus (Holmberg, 1887) and tilapia Oreochromis niloticus (Linnaeus, 1758) was tested by the Kirby-Bauer disk method, over Mueller-Hinton surface agar previously inoculated with 100 µL of bacterial suspensions. After regular incubation, i...

Effect of orally administered azadirachtin on non-specific immune parameters of goldfish Carassius auratus (Linn. 1758) and resistance against Aeromonas hydrophila.

Science.gov (United States)

Kumar, Saurav; Raman, R P; Pandey, P K; Mohanty, Snatashree; Kumar, Abhay; Kumar, Kundan

2013-02-01

Modulation of the immune responses using active bio-ingredients as a possible prophylaxis measure has been novel prospect for aquaculture. The present study evaluated the effects of azadirachtin EC 25% on non-specific immune responses in goldfish Carassius auratus and resistance against pathogenic bacteria Aeromonas hydrophila. The experimental trial for effects of azadirachtin on immuno-haematoloical parameters in goldfish was conducted by feeding the various levels of azadirachtin as control T(0) (without azadirachtin), T(1) (0.1%), T(2) (0.2%), T(3) (0.4%), T(4) (0.8%) and T(5) (1.6%) for a period of 28 days. Fishes were challenged with A. hydrophila 28 days post feeding and relative percentage survival (%) was recorded over 14 days post infection. Immuno-haematoloical (total erythrocyte count, total leukocyte count, haemoglobin, packed cell volume, NBT activity, phagocytic activity, serum lysozyme activity, myeloperoxidase activity, total immunoglobulin) and serum biochemical parameters (serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) and blood glucose) of fishes were examined at 14 and 28 days of feedings. Fish fed with azadirachtin, showed significantly (p 0.05) in the treatment groups compared to control groups. Azadirachtin at the concentration of 4 g kg(-1) showed significantly (p azadirachtin EC 25% (4 g kg(-1)) showed higher NBT activity, serum lysozyme, protein profiles, leukocyte counts and resistance against A. hydrophila infection and thus, can be used as a potential immunostimulant in aquaculture. Copyright © 2012 Elsevier Ltd. All rights reserved.

Transcriptome Analysis of the Innate Immunity-Related Complement System in Spleen Tissue of Ctenopharyngodon idella Infected with Aeromonas hydrophila.

Directory of Open Access Journals (Sweden)

Yunfei Dang

Full Text Available The grass carp (Ctenopharyngodon idella is an important commercial farmed herbivorous fish species in China, but is susceptible to Aeromonas hydrophila infections. In the present study, we performed de novo RNA-Seq sequencing of spleen tissue from specimens of a disease-resistant family, which were given intra-peritoneal injections containing PBS with or without a dose of A. hydrophila. The fish were sampled from the control group at 0 h, and from the experimental group at 4, 8, 12, 24, 48 and 72 h. 122.18 million clean reads were obtained from the normalized cDNA libraries; these were assembled into 425,260 contigs and then 191,795 transcripts. Of those, 52,668 transcripts were annotated with the NCBI Nr database, and 41,347 of the annotated transcripts were assigned into 90 functional groups. 20,569 unigenes were classified into six main categories, including 38 secondary KEGG pathways. 2,992 unigenes were used in the analysis of differentially expressed genes (DEGs. 89 of the putative DEGs were related to the immune system and 41 of them were involved in the complement and coagulation cascades pathway. This study provides insights into the complement and complement-related pathways involved in innate immunity, through expression profile analysis of the genomic resources in C. idella. We conclude that complement and complement-related genes play important roles during defense against A. hydrophila infection. The immune response is activated at 4 h after the bacterial injections, indicating that the complement pathways are activated at the early stage of bacterial infection. The study has improved our understanding of the immune response mechanisms in C. idella to bacterial pathogens.

Decolorisation of Congo Red by Aeromonas hydrophila Under Microaerophilic Conditions

International Nuclear Information System (INIS)

El Gizawy, S.; Refae, R.A.; Abd El Kareem, H.; Gomaa, O.M.; Hamed, H.

2009-01-01

Among 22 local bacterial isolates, Aeromonas hydrophila isolated from Bolti fish showed a remarkable ability to decolorize congo red under microaerophilic conditions (98.8% in 48 hrs) without prior adaptation. The bacterium had the ability to grow and decolorized high concentrations of congo red which varied from 50 to 1000 mg/l , the decolorisation was irrelevant to bacterial growth. The strain was capable of decolorizing congo red under a wide range of temperatures (20-40 degree C), ph (3-8), NaCl (0-200 mg/l) and also had the ability to decolorized mono, di and poly azo dyes. This bacterium is notable in its ability to decolorized the diazo congo red under extreme conditions of temperature, ph, salinity and high dye concentrations which makes it suitable for decolorisation under extreme industrial conditions

PEMBERIAN PROBIOTIK LACTOBACILLUS BREVIS DAN PREBIOTIK OLIGOSAKARIDA PADA BENIH PATIN SIAM (Pangasionodon hypophthalmus YANG DIINFEKSI Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

Yuke Eliyani

2013-08-01

Lactobacillus brevis, prebiotik oligosakarida dan sinbiotiknya terhadap jumlah bakteri Lactobacillus sp. dan total bakteri dalam usus, total eritrosit, total leukosit, diferensial leukosit, aktivitas fagositik, sintasan, tingkat pertumbuhan, serta FCR benih ikan patin siam yang diinfeksi Aeromonas hydrophila. Hasil uji karakteristik menunjukkan bahwa jenis probiotik dan patogen adalah Lactobacillus sp. dan Aeromonas hydrophila. Pada uji in vivo digunakan lima perlakuan yang terdiri atas K(+, K(-, probiotik (pro, prebiotik (pre serta sinbiotik (sin. Bakteri Lactobacillus sp. ditemukan di usus pada perlakuan probiotik dan sinbiotik dengan kisaran jumlah sekitar 101 sampai 106 (CFU/g. Total eritrosit, total leukosit, aktivitas fagositik berbeda nyata (P<0,05 dengan kontrol pada beberapa waktu pengamatan. Tingkat sintasan terendah diperoleh pada perlakuan K(+ sebesar 43,33±11,55; sedangkan empat perlakuan lainnya memperoleh nilai 100%. Tingkat pertumbuhan harian berbeda nyata antar perlakuan, nilai terbaik dicapai pada perlakuan pemberian sinbiotik sebesar 3,370±0,14. Nilai FCR perlakuan probiotik, prebiotik dan sinbiotik menunjukkan beda nyata dengan kontrol. Perlakuan sin, pre, pro memberikan nilai yang lebih baik pada total eritrosit, total leukosit, aktivitas fagositik, sintasan, pertumbuhan, dan FCR dibandingkan kontrol.

Antibiotic and heavy metal resistance of Aeromonas hydrophila and Edwardsiella tarda isolated from red hybrid tilapia (Oreochromis spp. coinfected with motile aeromonas septicemia and edwardsiellosis

Directory of Open Access Journals (Sweden)

S. W. Lee

2017-07-01

Full Text Available Aim: The aim of this study is to identify antibiogram and heavy metal resistance pattern of Aeromonas hydrophila and Edwardsiella tarda isolated from red hybrid tilapia (Oreochromis spp. coinfected with motile aeromonas septicemia and edwardsiellosis in four commercial fish farms. Materials and Methods: A. hydrophila and E. tarda were isolated using glutamate starch phenol red and xylose lysine deoxycholate (Merck, Germany as a selective medium, respectively. All the suspected bacterial colonies were identified using conventional biochemical tests and commercial identification kit (BBL Crystal, USA. Susceptibility testing of present bacterial isolates to 16 types of antibiotics (nalidixic acid, oxolinic acid, compound sulfonamides, doxycycline, tetracycline, novobiocin, chloramphenicol, kanamycin, sulfamethoxazole, flumequine, erythromycin, ampicillin, spiramycin, oxytetracycline, amoxicillin, and fosfomycin and four types of heavy metals (mercury, chromium, copper, and zinc were carried out using disk diffusion and two-fold agar dilution method, respectively. Results: Three hundred isolates of A. hydrophila and E. tarda were successfully identified by biochemical tests. Antibiotic susceptibility testing results showed that 42.2% of the bacterial isolates were sensitive to compound sulfonamides, sulfamethoxazole, flumequine, oxytetracycline, doxycycline, and oxolinic acid. On the other hand, 41.6% of these isolates were resistant to novobiocin, ampicillin, spiramycin, and chloramphenicol, which resulted for multiple antibiotic resistance index values 0.416. Among tested heavy metals, bacterial isolates exhibited resistant pattern of Zn2+ > Cr6+ > Cu2+ > Hg2+. Conclusion: Results from this study indicated that A. hydrophila and E. tarda isolated from coinfected farmed red hybrid tilapia were multi-resistant to antibiotics and heavy metals. These resistant profiles could be useful information to fish farmers to avoid unnecessary use of

PEMBERIAN TOTAL FENOL TERIPANG PASIR (Holothuria scabra UNTUK MENINGKATKAN LEUKOSIT DAN DIFERENSIAL LEUKOSIT IKAN MAS (Cyprinus carpio YANG DIINFEKSI BAKTERI Aeromonas Hydrophila

Directory of Open Access Journals (Sweden)

Achmad Suhermanto

2011-10-01

Full Text Available Freshwater fishery commodities are most likely to be increased production of carp (Cyprinus carpio. Intensification of cultivation which raises new problems with fish disease outbreaks caused by Aeromonas hydrophila. Providing of immunostimulatory bioactive compounds of sea cucumbers (Holothuria scabra can enhance non-specific immune responses in the goldfish as a mechanism of defense against disease. The purpose of this study is to determine the role and optimal dose of total phenols sea cucumber in enhancing non-specific immune response seen from the hematology parameters Extraction of bioactive components from sea cucumber prepared by using methanol and fractionated with ethyl acetate solvent (v/v. Identification of total phenols in ethyl acetate fraction performed using UV-Vis spectrophotometer and infrared. Total phenol produced was tested on carp with intraperitonial injection, the concentration of 0.09, 0.18 and 0.27 mg phenol/kg fish. Challenge test was done by using the Aeromonas hydrophila (107 cells/ml through the immersion method. The observations included hematological parameters and total plasma proteins.The observations of hematological parameters that Leukocytes, Neutrophils pre-and post-infection were significantly increased. Lymphocyte pre infection was increased significantly and post-bacterial infection was decreased significantly. Eosinophils, Monocytes pre-and post-bacterial infection were not differ significantly between treatment. The use of phenolic compounds at 0.09 mg / kg can be increase of non-specific immune response in carp (Cyprinus carpio. Key Words : Total phenol, Aeromonas hydrophila, Cyprinus carpio, nonspecific immune response 

Effectiveness of ambon banana stem juice as immunostimulatory against Aeromonas hydrophila infections in catfish Clarias gariepinus

OpenAIRE

Qorie Astria; Sri Nuryati; Kukuh Nirmala; Alimuddin Alimuddin

2017-01-01

ABSTRACT Outbreaks of infectious diseases due to Aeromonas hydrophila in catfish can cause high death rates (80–100%). Fish disease control can be done using phytopharmaceutical to prevent or treat diseases of fish. One of the phytopharmaceutical that known to prevent the fish diseases is ambon banana stem Musa cavendishii var. dwarf Paxton. This study was conducted to test the effectiveness of catfish immersion using banana stem juice as an immunostimulant against bacterial infections A. hyd...

White Mulberry (Morus alba Foliage Methanolic Extract Can Alleviate Aeromonas hydrophila Infection in African Catfish (Clarias gariepinus

Directory of Open Access Journals (Sweden)

Atefeh Sheikhlar

2014-01-01

Full Text Available Two experiments were simultaneously conducted with Morus alba (white mulberry foliage extract (MFE as a growth promoter and treatment of Aeromonas hydrophila infection in separate 60 and 30 days trail (Experiments 1 and 2, resp. in African catfish (Clarias gariepinus. In Experiment 1, four diets, control and control supplemented with 2, 5, or 7 g MFE/kg dry matter (DM of diet, were used. In Experiment 2, fish were intraperitoneally infected with Aeromonas hydrophila and fed the same diets as experiment 1 plus additional two diets with or without antibiotic. Results of experiment 1 showed that growth was unaffected by dietary levels of MFE. Treatments with the inclusion of MFE at the levels of 5 and 7 g/Kg DM had no mortality. Red blood cells (RBC, albumin, and total protein were all higher for the treatments fed MFE (5 and 7 g/Kg DM. Results of experiment 2 showed RBC, hemoglobin, hematocrit, globulin, albumin, and total protein improved with the increase in MFE in the infected fish. The dietary MFE at the level of 7 g/kg DM reduced mortality rate. In conclusion, MFE at the level of 7 g/kg DM could be a valuable dietary supplement to cure the infected fish.

White Mulberry (Morus alba) Foliage Methanolic Extract Can Alleviate Aeromonas hydrophila Infection in African Catfish (Clarias gariepinus)

Science.gov (United States)

Sheikhlar, Atefeh; Alimon, Abd Razk; Daud, Hassan; Saad, Chee R.; Webster, Carl D.; Meng, Goh Yong

2014-01-01

Two experiments were simultaneously conducted with Morus alba (white mulberry) foliage extract (MFE) as a growth promoter and treatment of Aeromonas hydrophila infection in separate 60 and 30 days trail (Experiments 1 and 2, resp.) in African catfish (Clarias gariepinus). In Experiment 1, four diets, control and control supplemented with 2, 5, or 7 g MFE/kg dry matter (DM) of diet, were used. In Experiment 2, fish were intraperitoneally infected with Aeromonas hydrophila and fed the same diets as experiment 1 plus additional two diets with or without antibiotic. Results of experiment 1 showed that growth was unaffected by dietary levels of MFE. Treatments with the inclusion of MFE at the levels of 5 and 7 g/Kg DM had no mortality. Red blood cells (RBC), albumin, and total protein were all higher for the treatments fed MFE (5 and 7 g/Kg DM). Results of experiment 2 showed RBC, hemoglobin, hematocrit, globulin, albumin, and total protein improved with the increase in MFE in the infected fish. The dietary MFE at the level of 7 g/kg DM reduced mortality rate. In conclusion, MFE at the level of 7 g/kg DM could be a valuable dietary supplement to cure the infected fish. PMID:25574488

White mulberry (Morus alba) foliage methanolic extract can alleviate Aeromonas hydrophila infection in African catfish (Clarias gariepinus).

Science.gov (United States)

Sheikhlar, Atefeh; Alimon, Abd Razk; Daud, Hassan; Saad, Chee R; Webster, Carl D; Meng, Goh Yong; Ebrahimi, Mahdi

2014-01-01

Two experiments were simultaneously conducted with Morus alba (white mulberry) foliage extract (MFE) as a growth promoter and treatment of Aeromonas hydrophila infection in separate 60 and 30 days trail (Experiments 1 and 2, resp.) in African catfish (Clarias gariepinus). In Experiment 1, four diets, control and control supplemented with 2, 5, or 7 g MFE/kg dry matter (DM) of diet, were used. In Experiment 2, fish were intraperitoneally infected with Aeromonas hydrophila and fed the same diets as experiment 1 plus additional two diets with or without antibiotic. Results of experiment 1 showed that growth was unaffected by dietary levels of MFE. Treatments with the inclusion of MFE at the levels of 5 and 7 g/Kg DM had no mortality. Red blood cells (RBC), albumin, and total protein were all higher for the treatments fed MFE (5 and 7 g/Kg DM). Results of experiment 2 showed RBC, hemoglobin, hematocrit, globulin, albumin, and total protein improved with the increase in MFE in the infected fish. The dietary MFE at the level of 7 g/kg DM reduced mortality rate. In conclusion, MFE at the level of 7 g/kg DM could be a valuable dietary supplement to cure the infected fish.

Experimental induction of motile Aeromonas septicemia in channel catfish (Ictalurus punctatus by waterborne challenge with virulent Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

Dunhua Zhang

2016-05-01

Full Text Available Motile Aeromonas septicemia (MAS, caused by virulent clonal isolates of Aeromonas hydrophila (vAh, is emerging as a major disease in catfish (Ictalurus punctatus aquaculture in the Southeastern United States. Predisposing conditions leading to vAh infection in catfish were however largely unknown. The objective of this study was to investigate factors that predispose catfish to vAh infection and establish a waterborne challenge model that mimics natural occurrence of MAS. Results of this study indicated that wounding on the fish body surface was one of the key factors that predisposed catfish to vAh infection via waterborne route. Relatively uniform wounds were created by clipping part of the fish adipose fin. Adipose fin clipped (Af-clipped fish behaved normally in terms of swimming and feeding and no mortality occurred in the control treatment (a mock challenge. When subjected to challenge in vAh-infected water, Af-clipped fish were highly susceptible, showing typical symptoms of MAS observed in the field. The mortality rate of Af-clipped fish was significantly associated with vAh concentration, challenge time and water temperature. About 90% mortality occurred within 48 h when Af-clipped fish were challenged for 1 h with vAh at the concentration of 2 × 107 colony forming units per mL of water (27 ± 1 °C. The waterborne challenge model was further tested using four field isolates including A. hydrophila and A. veronii. All vAh isolates caused about 90% mortality of Af-clipped fish and one isolate of Aeromonas veronii caused no mortality under the same challenge conditions. The waterborne challenge model described in this study would facilitate urgently-needed studies of MAS prevention (such as wound avoidance and healing and control (such as prophylactic vaccination; antibiotics treatment and probiotics screening. Keywords: Adipose fin, Channel catfish, Motile Aeromonas septicemia, Virulent Aeromonas hydrophila, Waterborne challenge

Effect of salinity and incubation time of planktonic cells on biofilm formation, motility, exoprotease production, and quorum sensing of Aeromonas hydrophila.

Science.gov (United States)

Jahid, Iqbal Kabir; Mizan, Md Furkanur Rahaman; Ha, Angela J; Ha, Sang-Do

2015-08-01

The aim of this study was to determine the effect of salinity and age of cultures on quorum sensing, exoprotease production, and biofilm formation by Aeromonas hydrophila on stainless steel (SS) and crab shell as substrates. Biofilm formation was assessed at various salinities, from fresh (0%) to saline water (3.0%). For young and old cultures, planktonic cells were grown at 30 °C for 24 h and 96 h, respectively. Biofilm formation was assessed on SS, glass, and crab shell; viable counts were determined in R2A agar for SS and glass, but Aeromonas-selective media was used for crab shell samples to eliminate bacterial contamination. Exoprotease activity was assessed using a Fluoro™ protease assay kit. Quantification of acyl-homoserine lactone (AHL) was performed using the bioreporter strain Chromobacterium violaceum CV026 and the concentration was confirmed using high-performance liquid chromatography (HPLC). The concentration of autoinducer-2 (AI-2) was determined with Vibrio harveyi BB170. The biofilm structure at various salinities (0-3 %) was assessed using field emission electron microscopy (FESEM). Young cultures of A. hydrophila grown at 0-0.25% salinity showed gradual increasing of biofilm formation on SS, glass and crab shell; swarming and swimming motility; exoproteases production, AHL and AI-2 quorum sensing; while all these phenotypic characters reduced from 0.5 to 3.0% salinity. The FESEM images also showed that from 0 to 0.25% salinity stimulated formation of three-dimensional biofilm structures that also broke through the surface by utilizing the chitin surfaces of crab, while 3% salinity stimulated attachment only for young cultures. However, in marked contrast, salinity (0.1-3%) had no effect on the stimulation of biofilm formation or on phenotypic characters for old cultures. However, all concentrations reduced biofilm formation, motility, protease production and quorum sensing for old culture. Overall, 0-0.25% salinity enhanced biofilm formation

Effects of Lactobacillus delbrueckii on immune response, disease resistance against Aeromonas hydrophila, antioxidant capability and growth performance of Cyprinus carpio Huanghe var.

Science.gov (United States)

Zhang, Chun-Nuan; Zhang, Ji-Liang; Guan, Wen-Chao; Zhang, Xiao-Fei; Guan, Su-Hua; Zeng, Qing-Hui; Cheng, Gao-Feng; Cui, Wei

2017-09-01

The aim of the present study was to investigate effects of dietary Lactobacillus delbrueckii (L. delbrueckii) on immune response, disease resistance against Aeromonas hydrophila (A. hydrophila), antioxidant capability and growth performance of Cyprinus carpio Huanghe var. 450 fish (mean weight of 1.05 ± 0.03 g) were randomly distributed into five groups that fed diets containing different levels of L. delbrueckii (0, 1 × 10 5 , 1 × 10 6 , 1 × 10 7 and 1 × 10 8  CFU g -1 ) for 8 weeks. The results showed that intestinal immune parameters such as lysozyme, acid phosphatase, and myeloperoxidase activities, immunoglobulin M content, and the survival rate were improved in fish fed with 1 × 10 6 and 1 × 10 7  CFU g -1 L. delbrueckii. In addition, 1 × 10 7  CFU g -1 L. delbrueckii supplementation down-regulated mRNA levels of TNF-α, IL-8, IL-1β and NF-κBp65, and up-regulated IL-10 and TGF-β mRNA levels in the intestine. The survival rate was significantly (P < 0.05) higher (68.33%) in fish fed 1 × 10 6  CFU g -1 L. delbrueckii than the control diet-fed group (40%) after challenge by A. hydrophila. Fish fed with diet containing 1 × 10 6  CFU g -1 L. delbrueckii showed higher antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and total antioxidant capacity (T-AOC) and lower MDA concentrations than those of the control group (P < 0.05). The relative gene expression (SOD, CAT, GPX) showed the same trend with their activities. In addition, the growth performance was significantly improved in fish fed with the diet containing 1 × 10 6 and 1 × 10 7  CFU g -1 L. delbrueckii (P < 0.05). These results demonstrated that dietary optimal levels of L. delbrueckii enhanced immunity, disease resistance against A. hydrophila antioxidant capability and growth performance in Cyprinus carpio Huanghe var. Copyright © 2017 Elsevier Ltd. All rights reserved.

Oreochromis mossambicus diet supplementation with Psidium guajava leaf extracts enhance growth, immune, antioxidant response and resistance to Aeromonas hydrophila.

Science.gov (United States)

Gobi, Narayanan; Ramya, Chinnu; Vaseeharan, Baskaralingam; Malaikozhundan, Balasubramanian; Vijayakumar, Sekar; Murugan, Kadarkarai; Benelli, Giovanni

2016-11-01

In this research, we focused on the efficacy of aqueous and ethanol leaf extracts of Psidium guajava L. (guava) based experimental diets on the growth, immune, antioxidant and disease resistance of tilapia, Oreochromis mossambicus following challenge with Aeromonas hydrophila. The experimental diets were prepared by mixing powdered (1, 5 and 10 mg/g) aqueous and ethanol extract of guava leaf with commercial diet. The growth (FW, FCR and SGR), non-specific cellular immune (myeloperoxidase activity, reactive oxygen activity and reactive nitrogen activity) humoral immune (complement activity, antiprotease, alkaline phosphatase activity and lysozyme activity) and antioxidant enzyme responses (SOD, GPX, and CAT) were examined after 30 days of post-feeding. A significant enhancement in the biochemical and immunological parameters of fish were observed fed with experimental diets compared to control. The dietary supplementation of P. guajava leaf extract powder for 30 days significantly reduced the mortality and increased the disease resistance of O. mossambicus following challenge with A. hydrophila at 50 μl (1 × 10 7  cells ml -1 ) compared to control after post-infection. The results suggest that the guava leaf extract could be used as a promising feed additive in aquaculture. Copyright © 2016 Elsevier Ltd. All rights reserved.

Molecular characterization and expression analysis of cathepsin C in Chinese giant salamander (Andrias davidianus after Aeromonas hydrophila infection

Directory of Open Access Journals (Sweden)

Zisheng Wang

2018-03-01

Full Text Available Background: Cathepsin C (CTSC (dipeptidyl peptidase I, DPPI, is a member of the papain superfamily of cysteine proteases and involves in a variety of host reactions. However, the information of CTST in Chinese giant salamander (Andrias davidianus, an amphibian species with important evolutionary position and economic values, remained unclear. Results: The full-length salamander CTSC cDNA contained a 96 bp of 5′-UTR, a 1392 bp of ORF encoding 463 amino acids, and a 95 bp of 3′-UTR. The salamander CTSC possessed several sequence features similar to other reported CTSCs such as a signal peptide, a propeptide and a mature peptide. The active site triad of Cys, His and Asn were also found existing in salamander CTSC. Salamander CTSC mRNA was constitutively expressed in all the examined tissues with significantly variant expression level. The highest expression of CTSC was in intestine, followed with stomach, spleen, lung and brain. Following Aeromonas hydrophila infection for 12 h, salamander CTSC was significantly up-regulated in several tissues including lung, spleen, brain, kidney, heart, stomach and skin. Conclusion: CTSC plays roles in the immune response to bacterial infection, which provided valuable information for further studying the functions of CTSC in salamander. Keywords: cDNA, CTSC, Dipeptidyl peptidase I, Gene expression, Hydrophila, Immune, Peptide, Sequence, Tissue

Loss of the flagellum happened only once in the fungal lineage: phylogenetic structure of Kingdom Fungi inferred from RNA polymerase II subunit genes

Directory of Open Access Journals (Sweden)

Hodson Matthew C

2006-09-01

Full Text Available Abstract Background At present, there is not a widely accepted consensus view regarding the phylogenetic structure of kingdom Fungi although two major phyla, Ascomycota and Basidiomycota, are clearly delineated. Regarding the lower fungi, Zygomycota and Chytridiomycota, a variety of proposals have been advanced. Microsporidia may or may not be fungi; the Glomales (vesicular-arbuscular mycorrhizal fungi may or may not constitute a fifth fungal phylum, and the loss of the flagellum may have occurred either once or multiple times during fungal evolution. All of these issues are capable of being resolved by a molecular phylogenetic analysis which achieves strong statistical support for major branches. To date, no fungal phylogeny based upon molecular characters has satisfied this criterion. Results Using the translated amino acid sequences of the RPB1 and RPB2 genes, we have inferred a fungal phylogeny that consists largely of well-supported monophyletic phyla. Our major results, each with significant statistical support, are: (1 Microsporidia are sister to kingdom Fungi and are not members of Zygomycota; that is, Microsporidia and fungi originated from a common ancestor. (2 Chytridiomycota, the only fungal phylum having a developmental stage with a flagellum, is paraphyletic and is the basal lineage. (3 Zygomycota is monophyletic based upon sampling of Trichomycetes, Zygomycetes, and Glomales. (4 Zygomycota, Basidiomycota, and Ascomycota form a monophyletic group separate from Chytridiomycota. (5 Basidiomycota and Ascomycota are monophyletic sister groups. Conclusion In general, this paper highlights the evolutionary position and significance of the lower fungi (Zygomycota and Chytridiomycota. Our results suggest that loss of the flagellum happened only once during early stages of fungal evolution; consequently, the majority of fungi, unlike plants and animals, are nonflagellated. The phylogeny we infer from gene sequences is the first one that is

Loss of the flagellum happened only once in the fungal lineage: phylogenetic structure of kingdom Fungi inferred from RNA polymerase II subunit genes.

Science.gov (United States)

Liu, Yajuan J; Hodson, Matthew C; Hall, Benjamin D

2006-09-29

At present, there is not a widely accepted consensus view regarding the phylogenetic structure of kingdom Fungi although two major phyla, Ascomycota and Basidiomycota, are clearly delineated. Regarding the lower fungi, Zygomycota and Chytridiomycota, a variety of proposals have been advanced. Microsporidia may or may not be fungi; the Glomales (vesicular-arbuscular mycorrhizal fungi) may or may not constitute a fifth fungal phylum, and the loss of the flagellum may have occurred either once or multiple times during fungal evolution. All of these issues are capable of being resolved by a molecular phylogenetic analysis which achieves strong statistical support for major branches. To date, no fungal phylogeny based upon molecular characters has satisfied this criterion. Using the translated amino acid sequences of the RPB1 and RPB2 genes, we have inferred a fungal phylogeny that consists largely of well-supported monophyletic phyla. Our major results, each with significant statistical support, are: (1) Microsporidia are sister to kingdom Fungi and are not members of Zygomycota; that is, Microsporidia and fungi originated from a common ancestor. (2) Chytridiomycota, the only fungal phylum having a developmental stage with a flagellum, is paraphyletic and is the basal lineage. (3) Zygomycota is monophyletic based upon sampling of Trichomycetes, Zygomycetes, and Glomales. (4) Zygomycota, Basidiomycota, and Ascomycota form a monophyletic group separate from Chytridiomycota. (5) Basidiomycota and Ascomycota are monophyletic sister groups. In general, this paper highlights the evolutionary position and significance of the lower fungi (Zygomycota and Chytridiomycota). Our results suggest that loss of the flagellum happened only once during early stages of fungal evolution; consequently, the majority of fungi, unlike plants and animals, are nonflagellated. The phylogeny we infer from gene sequences is the first one that is congruent with the widely accepted morphology

Assessment of Aquaflor (c), copper sulfate and potassium permanganate for control of Aeromonas hydrophila and Flavobacterium columnare infection in sunshine bass, Morone chrysops female x Morone saxatilis male

Science.gov (United States)

Two experiments were conducted to assess different therapeutants against a mixed infection of Aeromonas hydrophila and Flavobacterium columnare in sunshine bass (SB) (Morone chrysops female x Morone saxatilis male). Experiment 1 assessed the efficacy of copper sulfate (CuSO4), florfenicol-medicated...

Understanding effects of chemical structure on azo dye decolorization characteristics by Aeromonas hydrophila

Energy Technology Data Exchange (ETDEWEB)

Hsueh, Chung-Chuan [Department of Chemical and Materials Engineering, National I-Lan University, I-Lan 260, Taiwan (China); Chen, Bor-Yann, E-mail: bychen@niu.edu.tw [Department of Chemical and Materials Engineering, National I-Lan University, I-Lan 260, Taiwan (China); Yen, Chia-Yi [Department of Chemical and Materials Engineering, National I-Lan University, I-Lan 260, Taiwan (China)

2009-08-15

This novel comparative study tended to disclose how the molecular structures present in seven azo dyes including two types of azo dyes (i.e., naphthol type azo dyes - Reactive Black 5 (RB 5), Reactive Blue 171 (RB 171), Reactive Green 19 (RG19), Reactive Red 198 (RR198), Reactive Red 141 (RR141) and non-naphthol type azo dyes - Direct Yellow 86 (DY86), Reactive Yellow 84 (RY84)) affected color removal capability of Aeromonas hydrophila. Generally speaking, the decolorization rate of naphthol type azo dye with hydroxyl group at ortho to azo bond was faster than that of non-naphthol type azo dye without hydroxyl group, except of RG19. The azo dyes with electron-withdrawing groups (e.g., sulfo group in RR198, RB5 and RR141) would be easier to be decolorized than the azo dyes with the electron-releasing groups (e.g., -NH-triazine in RB171 and RG19). In addition, the azo dyes containing more electron-withdrawing groups (e.g., RR198, RB5 and RR141) showed significantly faster rate of decolorization. The azo dyes with electron-withdrawing groups (e.g., sulfo group) at para and ortho to azo bond (e.g., RR198, RB5 and RR141) could be more preferred for color removal than those at meta (e.g., DY86 and RY84). The former azo dyes with para and ortho sulfo group provided more effective resonance effects to withdraw electrons from azo bond, causing azo dyes to be highly electrophilic for faster rates of reductive biodecolorization. However, since the ortho substituent caused steric hindrance near azo linkage(s), azo dyes with para substituent could be more favorable (e.g., SO{sub 2}(CH{sub 2}){sub 2}SO{sub 4}{sup -} in RR198 and RB5) than those with ortho substituent (e.g., sulfo group at RR141) for decolorization. Thus, the ranking of the position for the electron-withdrawing substituent in azo dyes to escalate decolorization was para > ortho > meta. This study suggested that both the positions of substituents on the aromatic ring and the electronic characteristics of

Effects of dietary administration of stinging nettle (Urtica dioica) on the growth performance, biochemical, hematological and immunological parameters in juvenile and adult Victoria Labeo (Labeo victorianus) challenged with Aeromonas hydrophila.

Science.gov (United States)

Ngugi, Charles C; Oyoo-Okoth, Elijah; Mugo-Bundi, James; Orina, Paul Sagwe; Chemoiwa, Emily Jepyegon; Aloo, Peninah A

2015-06-01

We investigated effects of dietary administration of stinging nettle (Urtica dioica) on growth performance, biochemical, hematological and immunological parameters in juvenile and adult Victoria Labeo (Labeo victorianus) against Aeromonas hydrophila. Fish were divided into 4 groups and fed for 4 and 16 weeks with 0%, 1%, 2% and 5% of U. dioica incorporated into the diet. Use of U. dioica in the diet resulted in improved biochemical, hematological and immunological parameters. Among the biochemical parameters; plasma cortisol, glucose, triglyceride and cholesterol decreased while total protein and albumin in fish increased with increasing dietary inclusion of U. dioica. Among the haematology parameters: red blood cell (RBC), white blood cell (WBC) counts, haematocrit (Htc), mean cell haemoglobin (MCH), mean cell haemoglobin concentration (MCHC) and netrophiles increased with increasing dietary inclusion levels of U. dioica, some depending on the fish age. Serum immunoglobulins, lysozyme activity and respiratory burst were the main immunological parameters in the adult and juvenile L. victorianus measured and they all increased with increasing herbal inclusion of U. dioica in the diet. Dietary incorporation of U. dioica at 5% showed significantly higher relative percentage survival (up to 95%) against A. hydrophila. The current results demonstrate that using U. dioica can stimulate fish immunity and make L. victorianus more resistant to bacterial infection (A. hydrophila). Copyright © 2015 Elsevier Ltd. All rights reserved.

Leaves from banana (Musa nana) and maize (Zea mays) have no phyto-prophylactic effects on the susceptibility of grass carp (Ctenopharyngodon idella) to Aeromonas hydrophila infection.

Science.gov (United States)

Mayrhofer, Richard; Menanteau-Ledouble, Simon; Pucher, Johannes; Focken, Ulfert; El-Matbouli, Mansour

2017-11-10

The ubiquitous and opportunistic bacterial pathogen Aeromonas hydrophila has been associated with ulcerative dermatitis in fish, especially under stressful conditions. It can cause severe losses in fresh water aquaculture and is particularly prevalent in tropical and subtropical regions. Fresh leaves from maize and bananas have been used as feed supplement by fish farmers in Vietnam and it has been reported that they may have phyto-prophylactic benefits. In the present study, a feeding trial was conducted to investigate the benefits of providing maize and banana leaves as feed supplement: to determine if they were taken up and digested by grass carp (Ctenopharyngodon idella), if this uptake resulted in improved growth performance, and if leaf supplementation protected fish when challenged with A. hydrophila by intramuscular injection. All fish were fed an identical ratio of commercial pelleted feed relative to biomass. However, in 12/18 tanks, this diet was supplemented with either fresh banana leaves or fresh maize leaves; offered ad libitum. Addition of leaves increased the overall feed conversion ratio (FCR) significantly. However, if only the pellet were taken into account, then no difference was found between treatments. Changes to the isotopic composition of the fish showed leaf nutrient uptake occurred. No prophylactic effects of feeding banana or maize leaves were detected against infection with A. hydrophila, and the diet did not induce changes in the fish haematocrit. However, addition of the maize leaves was associated with significantly reduced severity of the skin lesions, which could improve the market value of the fish. Addition of the leaf supplement did not result in significantly improved growth performance. Similarly, the effect of the supplement on the fish survival to infection was not significant.

3-Amino 1,8-naphthalimide, a structural analog of the anti-cholera drug virstatin inhibits chemically-biased swimming and swarming motility in vibrios

Science.gov (United States)

Wang, Hongxia; Silva, Anisia J.; Benitez, Jorge A.

2017-01-01

A screen for inhibitors of Vibrio cholerae motility identified the compound 3-amino 1,8-naphthalimide (3-A18NI), a structural analog of the cholera drug virstatin. Similar to virstatin, 3-A18NI diminished cholera toxin production. In contrast, 3-A18NI impeded swimming and/or swarming motility of V. cholerae and V. parahemolyticus suggesting that it could target the chemotaxis pathway shared by the polar and lateral flagellar system of vibrios. 3-A18NI did not inhibit the expression of V. cholerae major flagellin FlaA or the assembly of its polar flagellum. Finally, 3-A18NI enhanced V. cholerae colonization mimicking the phenotype of chemotaxis mutants that exhibit counterclockwise-biased flagellum rotation. PMID:28392408

Application of the Indirect Immunoperoxidase Stain Technique to the Flagella of Azospirillum brasilense

Science.gov (United States)

Hall, Patrick G.; Krieg, Noel R.

1984-01-01

An indirect immunoperoxidase stain was used to demonstrate by electron microscopy that an antigenic difference exists between the polar flagellum and the lateral flagella of Azospirillum brasilense ATCC 29145. Images PMID:16346482

Inactivation kinetics of various chemical disinfectants on Aeromonas hydrophila planktonic cells and biofilms.

Science.gov (United States)

Jahid, Iqbal Kabir; Ha, Sang-Do

2014-05-01

The present article focuses on the inactivation kinetics of various disinfectants including ethanol, sodium hypochlorite, hydrogen peroxide, peracetic acid, and benzalkonium chloride against Aeromonas hydrophila biofilms and planktonic cells. Efficacy was determined by viable plate count and compared using a modified Weibull model. The removal of the biofilms matrix was determined by the crystal violet assay and was confirmed by field-emission scanning electron microscope. The results revealed that all the experimental data and calculated Weibull α (scale) and β (shape) parameters had a good fit, as the R(2) values were between 0.88 and 0.99. Biofilms are more resistant to disinfectants than planktonic cells. Ethanol (70%) was the most effective in killing cells in the biofilms and significantly reduced (preduction as well as the effectiveness of chemical disinfectants on biofilms. The study showed that the Weibull model could successfully be used on food and food contact surfaces to determine the exact contact time for killing biofilms-forming foodborne pathogens.

Label-free proteomic analysis of intestinal mucosa proteins in common carp (Cyprinus carpio) infected with Aeromonas hydrophila.

Science.gov (United States)

Di, Guilan; Li, Hui; Zhang, Chao; Zhao, Yanjing; Zhou, Chuanjiang; Naeem, Sajid; Li, Li; Kong, Xianghui

2017-07-01

Outbreaks of infectious diseases in common carp Cyprinus carpio, a major cultured fish in northern regions of China, constantly result in significant economic losses. Until now, information proteomic on immune defence remains limited. In the present study, a profile of intestinal mucosa immune response in Cyprinus carpio was investigated after 0, 12, 36 and 84 h after challenging tissues with Aeromonas hydrophila at a concentration of 1.4 × 10 8  CFU/mL. Proteomic profiles in different samples were compared using label-free quantitative proteomic approach. Based on MASCOT database search, 1149 proteins were identified in samples after normalisation of proteins. Treated groups 1 (T1) and 2 (T2) were first clustered together and then clustered with control (C group). The distance between C and treated group 3 (T3) represented the maxima according to hierarchical cluster analysis. Therefore, comparative analysis between C and T3 was selected in the following analysis. A total of 115 proteins with differential abundance were detected to show conspicuous expressing variances. A total of 52 up-regulated proteins and 63 down-regulated proteins were detected in T3. Gene ontology analysis showed that identified up-regulated differentially expressed proteins in T3 were mainly localised in the hemoglobin complex, and down-regulated proteins in T3 were mainly localised in the major histocompatibility complex II protein complex. Forty-six proteins of differential abundance (40% of 115) were involved in immune response, with 17 up-regulated and 29 down-regulated proteins detected in T3. This study is the first to report proteome response of carp intestinal mucosa against A. hydrophila infection; information obtained contribute to understanding defence mechanisms of carp intestinal mucosa. Copyright © 2017 Elsevier Ltd. All rights reserved.

Efficacy of florfenicol, copper sulfate and potassium permanganate in controlling a natural infection of Aeromonas hydrophila and Flavobacterium columnare in sunshine bass, Morone chrysops female x Morone saxatilis male

Science.gov (United States)

Sunshine bass (Morone chrysops female ' Morone saxatilis male) naturally infected with Aeromonas hydrophila and Flavobacterium columnare were randomly assigned to six treatments: 1) two treatments of waterborne exposures to copper sulfate (CuSO4), at 2.1 and at 4.2 mg/L (approximately one and two pe...

Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 3: developmental changes in spermatid flagellum and cytoplasmic droplet and interaction of sperm with the zona pellucida and egg plasma membrane.

Science.gov (United States)

Hermo, Louis; Pelletier, R-Marc; Cyr, Daniel G; Smith, Charles E

2010-04-01

Spermiogenesis constitutes the steps involved in the metamorphosis of spermatids into spermatozoa. It involves modification of several organelles in addition to the formation of several structures including the flagellum and cytoplasmic droplet. The flagellum is composed of a neck region and middle, principal, and end pieces. The axoneme composed of nine outer microtubular doublets circularly arranged to form a cylinder around a central pair of microtubules is present throughout the flagellum. The middle and principal pieces each contain specific components such as the mitochondrial sheath and fibrous sheath, respectively, while outer dense fibers are common to both. A plethora of proteins are constituents of each of these structures, with each playing key roles in functions related to the fertility of spermatozoa. At the end of spermiogenesis, a portion of spermatid cytoplasm remains associated with the released spermatozoa, referred to as the cytoplasmic droplet. The latter has as its main feature Golgi saccules, which appear to modify the plasma membrane of spermatozoa as they move down the epididymal duct and hence may be partly involved in male gamete maturation. The end product of spermatogenesis is highly streamlined and motile spermatozoa having a condensed nucleus equipped with an acrosome. Spermatozoa move through the female reproductive tract and eventually penetrate the zona pellucida and bind to the egg plasma membrane. Many proteins have been implicated in the process of fertilization as well as a plethora of proteins involved in the development of spermatids and sperm, and these are high lighted in this review. Copyright 2009 Wiley-Liss, Inc.

3-Amino 1,8-naphthalimide, a structural analog of the anti-cholera drug virstatin inhibits chemically-biased swimming and swarming motility in vibrios.

Science.gov (United States)

Wang, Hongxia; Silva, Anisia J; Benitez, Jorge A

2017-06-01

A screen for inhibitors of Vibrio cholerae motility identified the compound 3-amino 1,8-naphthalimide (3-A18NI), a structural analog of the cholera drug virstatin. Similar to virstatin, 3-A18NI diminished cholera toxin production. In contrast, 3-A18NI impeded swimming and/or swarming motility of V. cholerae and V. parahemolyticus suggesting that it could target the chemotaxis pathway shared by the polar and lateral flagellar system of vibrios. 3-A18NI did not inhibit the expression of V. cholerae major flagellin FlaA or the assembly of its polar flagellum. Finally, 3-A18NI enhanced V. cholerae colonization mimicking the phenotype of chemotaxis mutants that exhibit counterclockwise-biased flagellum rotation. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Jerusalem artichoke enriched diet on growth performance, immuno-hematological changes and disease resistance against Aeromonas hydrophila in Asian seabass (Lates calcarifer).

Science.gov (United States)

Syed Raffic Ali, Sajjad; Ambasankar, Kondusamy; Saiyad Musthafa, Mohamed; Harikrishnan, Ramasamy

2017-11-01

A 45 days feeding trial was conducted to study the effect of Jerusalem artichoke (JA) on growth performance, body composition, biochemical, immuno-hematological parameters and disease resistance in Asian seabass (Lates calcarifer) fingerlings against Aeromonas hydrophila. JA was supplemented at three different levels viz., control 0, 5, 10, and 20 g kg -1 in the commercial diet (403 g kg -1 protein and 89 g kg -1 lipid) in L. calcarifer. The results showed that there were no significant (P > 0.05) differences in various growth parameters, while the whole body composition showed significant differences (P  0.05) affected by dietary supplementation of JA at different concentration. However, the mean corpuscular volume (MCV) was significantly (P < 0.05) higher in the fish fed with 20 g kg -1  JA supplemented diet. Biochemical parameters revealed that glucose, urea, cholesterol, and triglyceride showed significant (P < 0.05) differences between control and treatments groups. Interestingly, 20 g kg -1  JA supplemented diet significantly modulates the innate immune response and disease resistance against Aeromonas hydrophila compared with control and other treatment groups. The results of the study revealed that 20 g kg -1  JA supplementation has a beneficial effect in the biochemical, immunological and disease resistance in L. calcarifer juveniles. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Effects of replacing soybean meal with rubber seed meal on growth, antioxidant capacity, non-specific immune response, and resistance to Aeromonas hydrophila in tilapia (Oreochromis niloticus × O. aureus).

Science.gov (United States)

Deng, Junming; Mai, Kangsen; Chen, Liqiao; Mi, Haifeng; Zhang, Lu

2015-06-01

This study evaluated the effects of replacing soybean meal (SBM) with rubber seed meal (RSM) on growth, antioxidant capacity, non-specific immune response and resistance to Aeromonas hydrophila in tilapia (Oreochromis niloticus × Oreochromis aureus). Five experimental diets were formulated with 0 (control), 10, 20, 30, and 40% RSM replacing graded levels of SBM, respectively. Fish were fed one of the five experimental diets for eight weeks, and then challenged by A. hydrophila via intraperitoneal injection and kept for seven days. Dietary RSM inclusion level up to 30% did not affect the weight gain and daily growth coefficient, whereas these were depressed by a further inclusion. Fish fed diet with 40% RSM showed the lowest serum total antioxidant capacity, lysozyme, alternative complement pathway, respiratory burst and phagocytic activities. Dietary RSM inclusion gradually depressed the post-challenge survival rate, and that was significantly lower in fish fed diet with 40% RSM compared to fish fed the control diet. Conversely, the inclusion of RSM generally increased the serum total cholesterol level, the plasma alanine aminotransferase and aspartate aminotransferase activities, and these were significantly higher in fish fed diet with 40% RSM compared to fish fed the control diet. The results indicated that RSM can be included at level up to 30% in diet for tilapia without obvious adverse effects on the growth, antioxidant capacity, non-specific immune response and resistance to A. hydrophila infection, whereas these were depressed by a further inclusion. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of The Antibacterial Effects of The New Benzothiazole and Tetrahydropyrimidine Derivatives against Streptococcus Iniae, Edwardsiella Tarda and Aeromonas Hydrophila as Some Zoonotic Bacterial Pathogens

Directory of Open Access Journals (Sweden)

Reza Aryan

2016-09-01

Full Text Available Background & Objective: The novel stronger antibacterial compounds such as the thiazole and pyrimidine derivatives are needed in order to remove the threat of bacterial antibiotic resistance in zoonotic aquatic bacterial pathogens. In this study, we evaluated the inhibitory effect of the new benzothiazole and tetrahydropyrimidine derivatives against three important zoonotic aquatic pathogens including Streptococcus iniae, Edwardsiella tarda and Aeromonas hydrophila. Material & Methods: Benzothiazole and tetrahydropyrimidine derivatives were synthesized and dissolved in DMSO with a concentration of 8129 μg/mL. Then, the disk diffusion and broth microdilution methods were applied to evaluate the antibacterial effects. Results were recorded as the minimum inhibitory concentration (MIC and the growth inhibition zone diameter. Results: The study showed that the two tetrahydropyrimidine derivatives had no inhibition effects on all of the studied bacteria. Moreover, no inhibitory effect was observed from the three banzothiazole derivatives against A. hydrophila. However, the benzothiazole derivatives showed significant inhibitory effect against S. iniae and E. tarda with MIC of 256-1024 µg/mL and the growth inhibition zone diameter of 4.3±0.3-18.2±0.1 mm. Conclusion: The antibacterial effect of the new banzothiazole derivatives was confirmed on S. iniae and E. tarda pathogens for the first time.  

Hericium caput-medusae (Bull.:Fr.) Pers. polysaccharide enhance innate immune response, immune-related genes expression and disease resistance against Aeromonas hydrophila in grass carp (Ctenopharyngodon idella).

Science.gov (United States)

Gou, Changlong; Wang, Jiazhen; Wang, Yuqiong; Dong, Wenlong; Shan, Xiaofeng; Lou, Yujie; Gao, Yunhang

2018-01-01

The objective was to add 0, 400, 800 or 1200 mg/kg of Hericium caput-medusae polysaccharide (HCMP) to the basal diet of grass carp (Ctenopharyngodon idella) and determine effects on humoral innate immunity, expression of immune-related genes and disease resistance. Adding HCMP enhanced (P < 0.05) bactericidal activity at 1, 2 and 3 weeks and also lysozyme activity, complement C3, and SOD activity at 2 and 3 weeks. Supplementing 800 or 1200 mg/kg of HCMP for 2 or 3 weeks increased (P < 0.05) serum concentrations of total protein, albumin and globulin. Two immune-related genes (IL-1β and TNF-α) were up-regulated (P < 0.05) in HCMP supplemented groups given 800 or 1200 mg/kg HCMP after 2 and 3 weeks of feeding. Expression of anti-inflammatory cytokine IL-10 was down-regulated (P < 0.05) after receiving 800 or 1200 mg/kg HCMP for 2 or 3 weeks. Fish fed 800 mg/kg HCMP had maximal disease resistance against Aeromonas hydrophila (65.4%). In conclusion, HCMP enhanced immune response and expression of immune-related genes and increased disease resistance against Aeromonas hydrophila in grass carp, with greatest effects in fish given 800 mg/kg HCMP for 3 weeks. Copyright © 2017 Elsevier Ltd. All rights reserved.

An Element of Determinism in a Stochastic Flagellar Motor Switch.

Science.gov (United States)

Xie, Li; Altindal, Tuba; Wu, Xiao-Lun

2015-01-01

Marine bacterium Vibrio alginolyticus uses a single polar flagellum to navigate in an aqueous environment. Similar to Escherichia coli cells, the polar flagellar motor has two states; when the motor is counter-clockwise, the cell swims forward and when the motor is clockwise, the cell swims backward. V. alginolyticus also incorporates a direction randomization step at the start of the forward swimming interval by flicking its flagellum. To gain an understanding on how the polar flagellar motor switch is regulated, distributions of the forward Δf and backward Δb intervals are investigated herein. We found that the steady-state probability density functions, P(Δf) and P(Δb), of freely swimming bacteria are strongly peaked at a finite time, suggesting that the motor switch is not Poissonian. The short-time inhibition is sufficiently strong and long lasting, i.e., several hundred milliseconds for both intervals, which is readily observed and characterized. Treating motor reversal dynamics as a first-passage problem, which results from conformation fluctuations of the motor switch, we calculated P(Δf) and P(Δb) and found good agreement with the measurements.

Involvement of SPI-2-encoded SpiC in flagellum synthesis in Salmonella enterica serovar Typhimurium

Directory of Open Access Journals (Sweden)

Sugita Asami

2009-08-01

Full Text Available Abstract Background SpiC encoded within Salmonella pathogenicity island 2 on the Salmonella enterica serovar Typhimurium chromosome is required for survival within macrophages and systemic infection in mice. Additionally, SpiC contributes to Salmonella-induced activation of the signal transduction pathways in macrophages by affecting the expression of FliC, a component of flagella filaments. Here, we show the contribution of SpiC in flagellum synthesis. Results Quantitative RT-PCR shows that the expression levels of the class 3 fliD and motA genes that encode for the flagella cap and motor torque proteins, respectively, were lower for a spiC mutant strain than for the wild-type Salmonella. Further, this mutant had lower expression levels of the class 2 genes including the fliA gene encoding the flagellar-specific alternative sigma factor. We also found differences in flagella assembly between the wild-type strain and the spiC mutant. Many flagella filaments were observed on the bacterial surface of the wild-type strain, whereas the spiC mutant had only few flagella. The absence of spiC led to reduced expression of the FlhD protein, which functions as the master regulator in flagella gene expression, although no significant difference at the transcription level of the flhDC operon was observed between the wild-type strain and the spiC mutant. Conclusion The data show that SpiC is involved in flagella assembly by affecting the post-transcription expression of flhDC.

Effect of guava leaves on the growth performance and cytokine gene expression of Labeo rohita and its susceptibility to Aeromonas hydrophila infection.

Science.gov (United States)

Giri, Sib Sankar; Sen, Shib Sankar; Chi, Cheng; Kim, Hyoun Joong; Yun, Saekil; Park, Se Chang; Sukumaran, V

2015-10-01

The present study aimed to evaluate the effects of Psidium guajava L. (guava) leaves on the growth and immune response of the fish species Labeo rohita and its susceptibility to Aeromonas hydrophila infection. Diets containing five different concentrations of guava leaves (0% [basal diet], 0.1% [G1], 0.5% [G2], 1% [G3], and 1.5% [G4]) were fed to fish (average weight: 11.1 g) for 60 days. Various growth and immune parameters were examined 60 days post-feeding. Fish were challenged with A. hydrophila at the end of the trial, and mortalities were recorded over 15 days post-infection. We found that growth parameters such as percent weight gain (657.61 ± 9.74) and specific growth rate (3.37 ± 0.021) were significantly higher in G2 group than in the control (P guava leaves at any concentration on plasma IgM level. Of the cytokine-related genes examined, interleukin-1beta (IL-1β) and tumour necrosis factor-alpha (TNF-α) were up-regulated in the head-kidney, intestine, and hepatopancreas of fish fed experimental diets, and expression was significantly higher in G2 and G3 than in the control group. In contrast, gene expression of IL-10, transforming growth factor-beta (TGF-β), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and transcription factor nuclear factor-κB (NF-κB) were down-regulated in the treatment groups. Moreover, fish fed the G2 diet exhibited a significantly higher post-challenge survival rate (66.66%). Collectively, these results suggest that dietary supplementation with guava leaves (at 0.5% concentration) could promote growth performance and strengthen immunity of L. rohita. Guava leaves therefore represent a promising feed additive for carps in aquaculture. Copyright © 2015 Elsevier Ltd. All rights reserved.

GENUS DESULFOMICROBIUM

Science.gov (United States)

Short, straight rod- or ellipsoidal-shaped cells (0.5-0.9 x 1.3-2.9 |m) with rounded ends, either singly or in pairs (Sharak Genthner et al., 1994). Gram-negative stain reaction and cell-wall structure. Cells are motile, usually by a single polar flagellum. Obligate anaerobe. End...

Two New Cyathane Diterpenoids from Mycelial Cultures of the Medicinal Mushroom Hericium erinaceus and the Rare Species, Hericium flagellum

Directory of Open Access Journals (Sweden)

Zeljka Rupcic

2018-03-01

Full Text Available Basidiomycetes of the genus Hericium are among the most praised medicinal and edible mushrooms, which are known to produce secondary metabolites with the potential to treat neurodegenerative diseases. This activity has been attributed to the discovery of various terpenoids that can stimulate the production of nerve growth factor (NGF or (as established more recently brain-derived neurotrophic factor (BDNF in cell-based bioassays. The present study reports on the metabolite profiles of a Lion’s Mane mushroom (Hericium erinaceus strain and a strain of the rare species, Hericium flagellum (synonym H. alpestre. While we observed highly similar metabolite profiles between the two strains that were examined, we isolated two previously undescribed metabolites, given the trivial names erinacines Z1 and Z2. Their chemical structures were elucidated by means of nuclear magnetic resonance (NMR spectroscopy and high resolution mass spectrometry. Along with six further, previously identified cyathane diterpenes, the novel erinacines were tested for neurotrophin inducing effects. We found that erinacines act on BDNF, which is a neurotrophic factor that has been reported recently by us to be induced by the corallocins, but as well on NGF expression, which is consistent with the literature.

Two New Cyathane Diterpenoids from Mycelial Cultures of the Medicinal Mushroom Hericium erinaceus and the Rare Species, Hericium flagellum.

Science.gov (United States)

Rupcic, Zeljka; Rascher, Monique; Kanaki, Sae; Köster, Reinhard W; Stadler, Marc; Wittstein, Kathrin

2018-03-06

Basidiomycetes of the genus Hericium are among the most praised medicinal and edible mushrooms, which are known to produce secondary metabolites with the potential to treat neurodegenerative diseases. This activity has been attributed to the discovery of various terpenoids that can stimulate the production of nerve growth factor ( NGF ) or (as established more recently) brain-derived neurotrophic factor ( BDNF ) in cell-based bioassays. The present study reports on the metabolite profiles of a Lion's Mane mushroom ( Hericium erinaceus ) strain and a strain of the rare species, Hericium flagellum (synonym H. alpestre ). While we observed highly similar metabolite profiles between the two strains that were examined, we isolated two previously undescribed metabolites, given the trivial names erinacines Z1 and Z2. Their chemical structures were elucidated by means of nuclear magnetic resonance (NMR) spectroscopy and high resolution mass spectrometry. Along with six further, previously identified cyathane diterpenes, the novel erinacines were tested for neurotrophin inducing effects. We found that erinacines act on BDNF , which is a neurotrophic factor that has been reported recently by us to be induced by the corallocins, but as well on NGF expression, which is consistent with the literature.

Surface contact stimulates the just-in-time deployment of bacterial adhesins.

Science.gov (United States)

Li, Guanglai; Brown, Pamela J B; Tang, Jay X; Xu, Jing; Quardokus, Ellen M; Fuqua, Clay; Brun, Yves V

2012-01-01

The attachment of bacteria to surfaces provides advantages such as increasing nutrient access and resistance to environmental stress. Attachment begins with a reversible phase, often mediated by surface structures such as flagella and pili, followed by a transition to irreversible attachment, typically mediated by polysaccharides. Here we show that the interplay between pili and flagellum rotation stimulates the rapid transition between reversible and polysaccharide-mediated irreversible attachment. We found that reversible attachment of Caulobacter crescentus cells is mediated by motile cells bearing pili and that their contact with a surface results in the rapid pili-dependent arrest of flagellum rotation and concurrent stimulation of polar holdfast adhesive polysaccharide. Similar stimulation of polar adhesin production by surface contact occurs in Asticcacaulis biprosthecum and Agrobacterium tumefaciens. Therefore, single bacterial cells respond to their initial contact with surfaces by triggering just-in-time adhesin production. This mechanism restricts stable attachment to intimate surface interactions, thereby maximizing surface attachment, discouraging non-productive self-adherence, and preventing curing of the adhesive. © 2011 Blackwell Publishing Ltd.

Polarization measurement for internal polarized gaseous targets

International Nuclear Information System (INIS)

Ye Zhenyu; Ye Yunxiu; Lv Haijiang; Mao Yajun

2004-01-01

The authors present an introduction to internal polarized gaseous targets, polarization method, polarization measurement method and procedure. To get the total nuclear polarization of hydrogen atoms (including the polarization of the recombined hydrogen molecules) in the target cell, authors have measured the parameters relating to atomic polarization and polarized hydrogen atoms and molecules. The total polarization of the target during our measurement is P T =0.853 ± 0.036. (authors)

Use of lupin, Lupinus perennis, mango, Mangifera indica, and stinging nettle, Urtica dioica, as feed additives to prevent Aeromonas hydrophila infection in rainbow trout, Oncorhynchus mykiss (Walbaum).

Science.gov (United States)

Awad, E; Austin, B

2010-05-01

Feeding rainbow trout, Oncorhynchus mykiss (Walbaum), with 1% lupin, Lupinus perennis, mango, Mangifera indica, or stinging nettle, Urtica dioica, for 14 days led to reductions in mortality after challenge with Aeromonas hydrophila. In addition, there was significant enhancement in serum bactericidal activity, respiratory burst and lysozyme activity in the treatment groups compared to the controls. Use of lupin and mango led to the highest number of red blood and white blood cells in recipient fish, with use of stinging nettle leading to the highest haematocrit and haemoglobin values; the highest value of mean corpuscular volume and haemoglobin was in the control groups and those fed with stinging nettle.

FliO Regulation of FliP in the Formation of the Salmonella enterica Flagellum

Science.gov (United States)

Barker, Clive S.; Meshcheryakova, Irina V.; Kostyukova, Alla S.; Samatey, Fadel A.

2010-01-01

The type III secretion system of the Salmonella flagellum consists of 6 integral membrane proteins: FlhA, FlhB, FliO, FliP, FliQ, and FliR. However, in some other type III secretion systems, a homologue of FliO is apparently absent, suggesting it has a specialized role. Deleting the fliO gene from the chromosome of a motile strain of Salmonella resulted in a drastic decrease of motility. Incubation of the ΔfliO mutant strain in motility agar, gave rise to pseudorevertants containing extragenic bypass mutations in FliP at positions R143H or F190L. Using membrane topology prediction programs, and alkaline phosphatase or GFPuv chimeric protein fusions into the FliO protein, we demonstrated that FliO is bitopic with its N-terminus in the periplasm and C-terminus in the cytoplasm. Truncation analysis of FliO demonstrated that overexpression of FliO43–125 or FliO1–95 was able to rescue motility of the ΔfliO mutant. Further, residue leucine 91 in the cytoplasmic domain was identified to be important for function. Based on secondary structure prediction, the cytoplasmic domain, FliO43–125, should contain beta-structure and alpha-helices. FliO43–125-Ala was purified and studied using circular dichroism spectroscopy; however, this domain was disordered, and its structure was a mixture of beta-sheet and random coil. Coexpression of full-length FliO with FliP increased expression levels of FliP, but coexpression with the cytoplasmic domain of FliO did not enhance FliP expression levels. Overexpression of the cytoplasmic domain of FliO further rescued motility of strains deleted for the fliO gene expressing bypass mutations in FliP. These results suggest FliO maintains FliP stability through transmembrane domain interaction. The results also demonstrate that the cytoplasmic domain of FliO has functionality, and it presumably becomes structured while interacting with its binding partners. PMID:20941389

FliO regulation of FliP in the formation of the Salmonella enterica flagellum.

Directory of Open Access Journals (Sweden)

Clive S Barker

2010-09-01

Full Text Available The type III secretion system of the Salmonella flagellum consists of 6 integral membrane proteins: FlhA, FlhB, FliO, FliP, FliQ, and FliR. However, in some other type III secretion systems, a homologue of FliO is apparently absent, suggesting it has a specialized role. Deleting the fliO gene from the chromosome of a motile strain of Salmonella resulted in a drastic decrease of motility. Incubation of the ΔfliO mutant strain in motility agar, gave rise to pseudorevertants containing extragenic bypass mutations in FliP at positions R143H or F190L. Using membrane topology prediction programs, and alkaline phosphatase or GFPuv chimeric protein fusions into the FliO protein, we demonstrated that FliO is bitopic with its N-terminus in the periplasm and C-terminus in the cytoplasm. Truncation analysis of FliO demonstrated that overexpression of FliO₄₃-₁₂₅ or FliO₁-₉₅ was able to rescue motility of the ΔfliO mutant. Further, residue leucine 91 in the cytoplasmic domain was identified to be important for function. Based on secondary structure prediction, the cytoplasmic domain, FliO₄₃-₁₂₅, should contain beta-structure and alpha-helices. FliO₄₃-₁₂₅-Ala was purified and studied using circular dichroism spectroscopy; however, this domain was disordered, and its structure was a mixture of beta-sheet and random coil. Coexpression of full-length FliO with FliP increased expression levels of FliP, but coexpression with the cytoplasmic domain of FliO did not enhance FliP expression levels. Overexpression of the cytoplasmic domain of FliO further rescued motility of strains deleted for the fliO gene expressing bypass mutations in FliP. These results suggest FliO maintains FliP stability through transmembrane domain interaction. The results also demonstrate that the cytoplasmic domain of FliO has functionality, and it presumably becomes structured while interacting with its binding partners.

ANTIBIOTICS RESISTANCE AND PUTATIVE VIRULENCE FACTORS OF AEROMONAS HYDROPHILA ISOLATED FROM ESTUARY

Directory of Open Access Journals (Sweden)

Olumide Adedokun Odeyemi

2012-06-01

Full Text Available This study aim to investigate antibiotics resistance profile and putative virulence factors of Aeromonas hydrophila isolated from estuary. Bacteria used for this study were isolated from water and sediment samples obtained from Sungai Melayu, Johor, Malaysia. Serially diluted 100 µL water and 1g sediment were inoculated on modified Rimler - Shott (mRS agar. Colonies with distinct cultural characteristics were picked for further studies. Isolates were tested for biofilm productions, protease enzyme and antibiotics resistance profile using agar well diffusion method against 10 commercial antibiotics. Congo Red Agar (CRA, Microplate and Standard Tube (ST methods were used for assessment of biofilm formation among the isolates while Skim Milk Agar was used for protease production. Sw.KMJ 3 and Sw.KMJ 9 produced black crystalline colonies on CRA. Six of the isolates were biofilm producers in ST method. Result of Microplate method, helped in grouping the isolates into weak (n = 8, moderate (n = 3 and strong producers (n = 4 at 540 nm wavelength. All the isolates were classified as weak ODc  ODi 0.1, moderate ODi = 0.1  0.12 and strong producers ODi  0.12 respectively at 540 nm wavelength. Antibiotics susceptibility test also revealed that all the isolates were resistant to between 6 and 10 antibiotics. Two isolates each were resistant to 6 (60 %, 7 (70 % and 9 (90 % antibiotics respectively. Eight of the isolates showed resistance to 8 (80 % antibiotics while only isolate Sw.KMJ-7 showed resistance to all the tested antibiotics. Sw.KMJ-3, Sw.KMJ-8 and Sw.KMJ-9 produced protease enzyme on SMA. The isolates were also found to be resistant to both antibiotics and heavy metals.

Parenteral immunization of PLA/PLGA nanoparticle encapsulating outer membrane protein (Omp) from Aeromonas hydrophila: Evaluation of immunostimulatory action in Labeo rohita (rohu).

Science.gov (United States)

Rauta, Pradipta Ranjan; Nayak, Bismita

2015-05-01

Advanced vaccine research approaches needs to explore on biodegradable nanoparticles (NPs) based vaccine carrier that can serve as antigen delivery systems as well as immuno-stimulatory action to induce both innate and adaptive immune response in fish. Immunogenicity of PLA and PLGA NPs encapsulating outer membrane protein (Omp) antigen of Aeromonas hydrophila were evaluated through intra-peritoneal injection in fish, Labeo rohita. Antigen loaded PLA-Omp (223.5 ± 13.19 nm) and PLGA-Omp (166.4 ± 21.23 nm) NPs were prepared using double emulsion method by efficiently encapsulating the antigen reaching the encapsulation efficiency 44 ± 4.58% and 59.33 ± 5.13% respectively. Our formulated PLA Omp and PLGA-Omp NPs were in nanometer range (PLA-Omp, it showed considerably slower antigen release in vitro than PLGA-Omp NPs. Other physical properties like zetapotential values and poly dispersity index (PDI) confirmed the stability as well as monodisperse nature of the formulated nanoparticles. The spherical and isolated nature of PLA-Omp and PLGA-Omp NPs were revealed by SEM analysis. Upon immunization of all antigenic formulations (PLA-Omp NP, PLGA-Omp NP, FIA-Omp, PLA NP, PLGA NP, PBS as control), significant higher bacterial agglutination titre and haemolytic activity were observed in case of PLA-Omp and PLGA-Omp immunized groups than rest groups at both 21 days and 42 days. The specific antibody response was significantly increased and persisted up to 42 days of post immunization by PLA-Omp, PLGA-Omp, FIA-Omp. PLA-Omp NPs showed better immune response (higher bacterial agglutination titre, haemolytic activity, specific antibody titre, higher percent survival upon A. hydrophila challenge) than PLGA-Omp in L. rohita confirming its better efficacy. Comparable antibody response of PLA-Omp and PLGA-Omp with FIA-Omp treated groups suggested that PLA and PLGA could be replacement for Freund's adjuvant (for stimulating antibody response) to overcome many side effects

Protective efficacy of Mucuna pruriens (L.) seed meal enriched diet on growth performance, innate immunity, and disease resistance in Oreochromis mossambicus against Aeromonas hydrophila.

Science.gov (United States)

Saiyad Musthafa, Mohamed; Asgari, Syed Mohideen; Kurian, Amitha; Elumalai, Preetham; Jawahar Ali, Abdul Rahman; Paray, Bilal Ahmad; Al-Sadoon, Mohammad K

2018-04-01

The impact of Mucuna pruriens (L.) seed meal diet on growth performance, innate immune response, and disease resistance in Oreochromis mossambicus against Aeromonas hydrophila is reported for the first time. Infected O. mossambicus was fed with 2 g kg -1 , 4 g kg -1 , and 6 g kg -1 of M. pruriens seed meal diets significantly increased initial body weight (IBW) and final body weight (FBW) over control, for a period of 4 weeks. At 4 g kg -1 and 6 g kg -1 the enriched diet significantly (P pruriens can be used as a feed additive to stimulate immunity for effective production of economically valuable freshwater fish, O. mossambicus. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of Euphorbia hirta plant leaf extract on immunostimulant response of Aeromonas hydrophila infected Cyprinus carpio

Science.gov (United States)

Sukumaran, NatarajaPillai

2014-01-01

The main objective of the present study is to improve the immune power of Cyprinus carpio by using Euphorbia hirta plant leaf extract as immunostimulants. The haematological, immunological and enzymatic studies were conducted on the medicated fish infected with Aeromonas hydrophila pathogen. The results obtained from the haematological studies show that the RBC count, WBC count and haemoglobin content were increased in the infected fish at higher concentration of leaf extract. The feeds with leaf extract of Euphorbia hirta were able to stimulate the specific immune response by increasing the titre value of antibody. It was able to stimulate the antibody production only up to the 5th day, when fed with higher concentrations of (25 g and 50 g) plant leaf extract. The plant extract showed non-specific immune responses such as lysozyme activity, phagocytic ratio, NBT assay, etc. at higher concentration (50 g) and in the same concentration (50 g), the leaf extract of Euphorbia hirta significantly eliminated the pathogen in blood and kidney. It was observed that fish have survival percentage significantly at higher concentration (50 g) of Euphorbia hirta, when compared with the control. The obtained results are statistically significant at P < 0.05 and P < 0.01 levels. This research work suggests that the plant Euphorbia hirta has immunostimulant activity by stimulating both specific and non-specific immunity at higher concentrations. PMID:25405077

Knockout of the alanine racemase gene in Aeromonas hydrophila HBNUAh01 results in cell wall damage and enhanced membrane permeability.

Science.gov (United States)

Liu, Dong; Zhang, Lu; Xue, Wen; Wang, Yaping; Ju, Jiansong; Zhao, Baohua

2015-07-01

This study focused on the alanine racemase gene (alr-2), which is involved in the synthesis of d-alanine that forms the backbone of the cell wall. A stable alr-2 knockout mutant of Aeromonas hydrophila HBNUAh01 was constructed. When the mutant was supplemented with d-alanine, growth was unaffected; deprivation of d-alanine caused the growth arrest of the starved mutant cells, but not cell lysis. No alanine racemase activity was detected in the culture of the mutant. Additionally, a membrane permeability assay showed increasing damage to the cell wall during d-alanine starvation. No such damage was observed in the wild type during culture. Scanning and transmission electron microscopy analyses revealed deficiencies of the cell envelope and perforation of the cell wall. Leakage of UV-absorbing substances from the mutants was also observed. Thus, the partial viability of the mutants and their independence of d-alanine for growth indicated that inactivation of alr-2 does not impose an auxotrophic requirement for d-alanine. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Pseudomonas mesophilica and an unnamed taxon, clinical isolates of pink-pigmented oxidative bacteria.

OpenAIRE

Gilardi, G L; Faur, Y C

1984-01-01

Twenty-one strains of pink-pigmented bacteria, isolated from human clinical specimens and an environmental source, were compared with Pseudomonas mesophilica ATCC 29983 and Protaminobacter ruber ATCC 8457. These isolates were gram-negative, oxidative rods which were motile by means of a single polar flagellum; gave positive catalase, indophenol oxidase, urease, and amylase reactions; and grew slowly at 30 degrees C. Fourteen isolates conformed to the designated type strains Pseudomonas mesoph...

Polarization of lanthanum nucleus by dynamic polarization method

International Nuclear Information System (INIS)

Adachi, Toshikazu; Ishimoto, Shigeru; Masuda, Yasuhiro; Morimoto, Kimio

1989-01-01

Preliminary studies have been carried out concerning the application of a dynamic polarization method to polarizing lanthanum fluoride single crystal to be employed as target in experiments with time reversal invariance. The present report briefly outlines the dynamic polarization method and describes some preliminary studies carried out so far. Dynamic polarization is of particular importance because no techniques are currently available that can produce highly polarized static nucleus. Spin interaction between electrons and protons (nuclei) plays a major role in the dynamic polarization method. In a thermal equilibrium state, electrons are polarized almost completely while most protons are not polarized. Positively polarized proton spin is produced by applying microwave to this system. The most hopeful candidate target material is single crystal of LaF 3 containing neodymium because the crystal is chemically stable and easy to handle. The spin direction is of great importance in experiments with time reversal invariance. The spin of neutrons in the target can be cancelled by adjusting the external magnetic field applied to a frozen polarized target. In a frozen spin state, the polarity decreases slowly with a relaxation time that depends on the external magnetic field and temperature. (N.K.)

Polarized neutrons

International Nuclear Information System (INIS)

Williams, W.G.

1988-01-01

The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

Screening probiotic candidates for a mixture of probiotics to enhance the growth performance, immunity, and disease resistance of Asian seabass, Lates calcarifer (Bloch), against Aeromonas hydrophila.

Science.gov (United States)

Lin, Hsueh-Li; Shiu, Ya-Li; Chiu, Chiu-Shia; Huang, Shih-Ling; Liu, Chun-Hung

2017-01-01

Six bacteria, including, Lactobacillus casei M15, Lac. plantarum D8, Lac. pentosus BD6, Lac. fermentum LW2, Enterococcus faecium 10-10, and Bacillus subtilis E20, and one yeast, Saccharomyces cerevisiae P13 were selected as probiotics for Asian seabass, Lates calcarifer, by tracking the growth performance and disease resistance of fish against Aeromonas hydrophila in the first trial. The probiotic efficiency screening results showed that B. subtilis E20 and Lac. pentosus BD6, and S. cerevisiae P13 and Lac. fermentum LW2 respectively improved either the growth performance or disease resistance. Therefore, these four probiotics were then selected to prepare a probiotics mixture, and this was incorporated in equal proportions into diets for Asian seabass at levels of 0 (control), and 10 6 (MD6), 10 7 (MD7), 10 8 (MD8), and 10 9 (MD9) colony-forming units (cfu) (kg diet) -1 . A synergistic effect of the combined probiotics was investigated in this study, and the probiotics mixture was able to improve both the growth performance and health status of fish. After 56 days of feeding, fish fed the MD9 diet had a higher final weight and percentage of weight gain. In addition, protein contents in the dorsal muscle of fish fed the MD8 and MD9 diets were significantly higher compared to the control. For the pathogen challenge test, fish fed the MD7, MD8, and MD9 diets had significantly lower cumulative mortalities after A. hydrophila infection compared to those of fish fed the control and MD6 diets, which might have been due to increased respiratory bursts, decreased superoxide dismutase activity in leucocytes, and increased phagocytic activity. Therefore, we considered that the probiotics mixture could adequately provide probiotic efficiency for Asian seabass, and the diet containing 10 9  cfu (kg diet) -1 probiotic mixture is recommended to improve the growth and health status of Asian seabass. Copyright © 2016. Published by Elsevier Ltd.

Workshop on polarized neutron filters and polarized pulsed neutron experiments

International Nuclear Information System (INIS)

Itoh, Shinichi

2004-07-01

The workshop was held in KEK by thirty-three participants on April 26, 2004. The polarized neutron filter method was only discussed. It consists of three parts; the first part was discussed on the polarized neutron methods, the second part on the polarized neutron experiments and the third on the pulse neutron spectrometer and polarized neutron experiments. The six papers were presented such as the polarized 3 He neutron spin filter, neutron polarization by proton polarized filter, soft master and neutron scattering, polarized neutron in solid physics, polarization experiments by chopper spectroscope and neutron polarization system in superHRPD. (S.Y.)

Biosorption of Cr(VI) from aqueous solution using A. hydrophila in up-flow column. Optimization of process variables

Energy Technology Data Exchange (ETDEWEB)

Hasan, S.H.; Srivastava, P.; Ranjan, D. [Banaras Hindu Univ., Varanasi (India). Water Pollution Research Lab.; Talat, M. [Banaras Hindu Univ., Varanasi (India). Dept. of Biochemistry

2009-06-15

In the present study, continuous up-flow fixed-bed column study was carried out using immobilized dead biomass of Aeromonas hydrophila for the removal of Cr(VI) from aqueous solution. Different polymeric matrices were used to immobilized biomass and polysulfone-immobilized biomass has shown to give maximum removal. The sorption capacity of immobilized biomass for the removal of Cr(VI) evaluating the breakthrough curves obtained at different flow rate and bed height. A maximum of 78.58% Cr(VI) removal was obtained at bed height of 19 cm and flow rate of 2 mL/min. Bed depth service time model provides a good description of experimental results with high correlation coefficient (>0.996). An attempt has been made to investigate the individual as well as cumulative effect of the process variables and to optimize the process conditions for the maximum removal of chromium from water by two-level two-factor full-factorial central composite design with the help of Minitab {sup registered} version 15 statistical software. The predicted results are having a good agreement (R{sup 2}=98.19%) with the result obtained. Sorption-desorption studies revealed that polysulfone-immobilized biomass could be reused up to 11 cycles and bed was completely exhausted after 28 cycles. (orig.)

Neutron polarization in polarized 3He targets

International Nuclear Information System (INIS)

Friar, J.L.; Gibson, B.F.; Payne, G.L.; Bernstein, A.M.; Chupp, T.E.

1990-01-01

Simple formulas for the neutron and proton polarizations in polarized 3 He targets are derived assuming (1) quasielastic final states; (2) no final-state interactions; (3) no meson-exchange currents; (4) large momentum transfers; (5) factorizability of 3 He SU(4) response-function components. Numerical results from a wide variety of bound-state solutions of the Faddeev equations are presented. It is found that this simple model predicts the polarization of neutrons in a fully polarized 3 He target to be 87%, while protons should have a slight residual polarization of -2.7%. Numerical studies show that this model works very well for quasielastic electron scattering

When measured spin polarization is not spin polarization

International Nuclear Information System (INIS)

Dowben, P A; Wu Ning; Binek, Christian

2011-01-01

Spin polarization is an unusually ambiguous scientific idiom and, as such, is rarely well defined. A given experimental methodology may allow one to quantify a spin polarization but only in its particular context. As one might expect, these ambiguities sometimes give rise to inappropriate interpretations when comparing the spin polarizations determined through different methods. The spin polarization of CrO 2 and Cr 2 O 3 illustrate some of the complications which hinders comparisons of spin polarization values. (viewpoint)

Chlorophytum borivilianum Polysaccharide Fraction Provokes the Immune Function and Disease Resistance of Labeo rohita against Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

Sib Sankar Giri

2015-01-01

Full Text Available The present study aimed to investigate the effects of Chlorophytum borivilianum polysaccharide (CBP, as a dietary supplement administered at varying concentrations with feed (basal diet, on various cytokine-related responses in Labeo rohita fingerlings. Immune parameters and immune-related gene expressions were measured at 3rd, 4th, and 5th week after feeding. The results revealed that dietary administration of CBP at 0.2% and 0.4% for 4 weeks significantly upregulated serum lysozyme and phagocytic activity. Complement C3 and respiratory burst activity (RBA were significantly higher after 4 weeks of CBP feeding. The immune related genes IL-8, IL-1β, TNF-α, and iNOS were downregulated (P<0.05 in groups with 0.2% and 0.4% CBP supplemented diets at week 4. Expression of anti-inflammatory cytokines (IL-10 and TGF-β was also downregulated (P<0.5 after 4 weeks of feeding with 0.2% to 0.8% CBP. However, five weeks of CBP administration had no significant effect on immune gene expression, except TNF-α and IL-8. Fish fed with 0.4% CBP for 4 weeks showed maximum resistance against Aeromonas hydrophila (73.3% survival compared to control. From these results, we recommend that CBP administration at 0.4% for 4 weeks could effectively improve immune response and disease resistance in L. rohita.

Aspects of constitutive and acquired antibioresistance in Aeromonas hydrophila strains isolated from water sources.

Science.gov (United States)

Balotescu, Carmen; Israil, Anca; Radu, Roxana; Alexandru, Ionela; Dobre, Georgeta

2003-01-01

Over the last three decades, the literature pointed out the implications of Aeromonas species in human pathology. These species were described as being involved in intestinal (several outbreaks of acute gastroenteritis of choleric/dysenteric form or chronic diarrhoea, ulcerative colitis, etc.) in normal adults or children, as well as in extraintestinal infections in immunocompromised hosts. This last aspect included a large range of cutaneous injuries (micronecrosis, abscesses, bums, cellulites, furunculosis), joint, bones, respiratory, urinary tract, ocular infections up to meningitis, endocarditis, peritonitis, hepatobilliary disease, endotoxic shock and septicemia (as consequence of leech microvascular surgery). During the last decade, the literature reported a high mortality in Aeromonas infections determined by certain phenospecies (A. hydrophila and A. veronii) especially in extraintestinal infections in immunocompromised patients. In microbiologists' opinion this high rate of mortality was probably due to poor knowledge concerning the aspects of antibioresistance in Aeromonas strains, to empiric treatments with antibiotics to which these bacteria exhibiting constitutive resistance lead to insuccessful results, and at last to the increasing trend of aeromonads resistance to certain antibiotics after 1996. The literature mentioned also that for a great number of Beta-lactamase producing Aeromonas strains, the use of microdilution method (by comparison to disk diffusion in agar medium) giving false results made more difficult the true knowledge of Aeromonas antibioresistance patterns. At the same time, in 2002, the literature mentioned 4 ecological compartments considered as "reservoirs for dissemination and transfer of microbial antibioresistance i.e. humans, animals, plants and natural soil and water. In the last time, more and more data of the literature revealed that some bacteria with role of reservoir of antibioresistance in the natural environment, even

Research on generating various polarization-modes in polarized illumination system

Science.gov (United States)

Huang, Jinping; Lin, Wumei; Fan, Zhenjie

2013-08-01

With the increase of the numerical aperture (NA), the polarization of light affects the imaging quality of projection lens more significantly. On the contrary, according to the mask pattern, the resolution of projection lens can be improved by using the polarized illumination. That is to say, using the corresponding polarized beam (or polarization-mode) along with the off-axis illumination will improve the resolution and the imaging quality of the of projection lens. Therefore, the research on the generation of various polarization modes and its conversion methods become more and more important. In order to realize various polarization modes in polarized illumination system, after read a lot of references, we provide a way that fitting for the illumination system with the wavelength of 193nm.Six polarization-modes and a depolarized mode are probably considered. Wave-plate stack is used to generate linearly polarization-mode, which have a higher degree polarization. In order to generate X-Y and Y-X polarization mode, the equipment consisting of four sectors of λ/2 wave plate was used. We combined 16 sectors of λ/2 wave plate which have different orientations of the "slow" axis to generate radial and azimuthal polarization. Finally, a multi-polarization control device was designed. Using the kind of multi-polarization control device which applying this method could help to choose the polarization modes conveniently and flexibility for the illumination system.

Polarization properties of linearly polarized parabolic scaling Bessel beams

Energy Technology Data Exchange (ETDEWEB)

Guo, Mengwen; Zhao, Daomu, E-mail: zhaodaomu@yahoo.com

2016-10-07

The intensity profiles for the dominant polarization, cross polarization, and longitudinal components of modified parabolic scaling Bessel beams with linear polarization are investigated theoretically. The transverse intensity distributions of the three electric components are intimately connected to the topological charge. In particular, the intensity patterns of the cross polarization and longitudinal components near the apodization plane reflect the sign of the topological charge. - Highlights: • We investigated the polarization properties of modified parabolic scaling Bessel beams with linear polarization. • We studied the evolution of transverse intensity profiles for the three components of these beams. • The intensity patterns of the cross polarization and longitudinal components can reflect the sign of the topological charge.

Social motility in african trypanosomes.

Directory of Open Access Journals (Sweden)

Michael Oberholzer

2010-01-01

Full Text Available African trypanosomes are devastating human and animal pathogens that cause significant human mortality and limit economic development in sub-Saharan Africa. Studies of trypanosome biology generally consider these protozoan parasites as individual cells in suspension cultures or in animal models of infection. Here we report that the procyclic form of the African trypanosome Trypanosoma brucei engages in social behavior when cultivated on semisolid agarose surfaces. This behavior is characterized by trypanosomes assembling into multicellular communities that engage in polarized migrations across the agarose surface and cooperate to divert their movements in response to external signals. These cooperative movements are flagellum-mediated, since they do not occur in trypanin knockdown parasites that lack normal flagellum motility. We term this behavior social motility based on features shared with social motility and other types of surface-induced social behavior in bacteria. Social motility represents a novel and unexpected aspect of trypanosome biology and offers new paradigms for considering host-parasite interactions.

Polarized nuclear target based on parahydrogen induced polarization

OpenAIRE

Budker, D.; Ledbetter, M. P.; Appelt, S.; Bouchard, L. S.; Wojtsekhowski, B.

2012-01-01

We discuss a novel concept of a polarized nuclear target for accelerator fixed-target scattering experiments, which is based on parahydrogen induced polarization (PHIP). One may be able to reach a 33% free-proton polarization in the ethane molecule. The potential advantages of such a target include operation at zero magnetic field, fast ($\\sim$100 Hz) polarization reversal, and operation with large intensity of an electron beam.

Functional genomic characterization of virulence factors from necrotizing fasciitis-causing strains of Aeromonas hydrophila.

Science.gov (United States)

Grim, Christopher J; Kozlova, Elena V; Ponnusamy, Duraisamy; Fitts, Eric C; Sha, Jian; Kirtley, Michelle L; van Lier, Christina J; Tiner, Bethany L; Erova, Tatiana E; Joseph, Sandeep J; Read, Timothy D; Shak, Joshua R; Joseph, Sam W; Singletary, Ed; Felland, Tracy; Baze, Wallace B; Horneman, Amy J; Chopra, Ashok K

2014-07-01

The genomes of 10 Aeromonas isolates identified and designated Aeromonas hydrophila WI, Riv3, and NF1 to NF4; A. dhakensis SSU; A. jandaei Riv2; and A. caviae NM22 and NM33 were sequenced and annotated. Isolates NF1 to NF4 were from a patient with necrotizing fasciitis (NF). Two environmental isolates (Riv2 and -3) were from the river water from which the NF patient acquired the infection. While isolates NF2 to NF4 were clonal, NF1 was genetically distinct. Outside the conserved core genomes of these 10 isolates, several unique genomic features were identified. The most virulent strains possessed one of the following four virulence factors or a combination of them: cytotoxic enterotoxin, exotoxin A, and type 3 and 6 secretion system effectors AexU and Hcp. In a septicemic-mouse model, SSU, NF1, and Riv2 were the most virulent, while NF2 was moderately virulent. These data correlated with high motility and biofilm formation by the former three isolates. Conversely, in a mouse model of intramuscular infection, NF2 was much more virulent than NF1. Isolates NF2, SSU, and Riv2 disseminated in high numbers from the muscular tissue to the visceral organs of mice, while NF1 reached the liver and spleen in relatively lower numbers on the basis of colony counting and tracking of bioluminescent strains in real time by in vivo imaging. Histopathologically, degeneration of myofibers with significant infiltration of polymorphonuclear cells due to the highly virulent strains was noted. Functional genomic analysis provided data that allowed us to correlate the highly infectious nature of Aeromonas pathotypes belonging to several different species with virulence signatures and their potential ability to cause NF. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Fusion of a polarized projectile with a polarized target

International Nuclear Information System (INIS)

Christley, J.A.; Johnson, R.C.; Thompson, I.J.

1995-01-01

The fusion cross sections for a polarized target with both unpolarized and polarized projectiles are studied. Expressions for the observables are given for the case when both nuclei are polarized. Calculations for fusion of an aligned 165 Ho target with 16 O and polarized 7 Li beams are presented

Update of the Polar SWIFT model for polar stratospheric ozone loss (Polar SWIFT version 2)

Science.gov (United States)

Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

2017-07-01

The Polar SWIFT model is a fast scheme for calculating the chemistry of stratospheric ozone depletion in polar winter. It is intended for use in global climate models (GCMs) and Earth system models (ESMs) to enable the simulation of mutual interactions between the ozone layer and climate. To date, climate models often use prescribed ozone fields, since a full stratospheric chemistry scheme is computationally very expensive. Polar SWIFT is based on a set of coupled differential equations, which simulate the polar vortex-averaged mixing ratios of the key species involved in polar ozone depletion on a given vertical level. These species are O3, chemically active chlorine (ClOx), HCl, ClONO2 and HNO3. The only external input parameters that drive the model are the fraction of the polar vortex in sunlight and the fraction of the polar vortex below the temperatures necessary for the formation of polar stratospheric clouds. Here, we present an update of the Polar SWIFT model introducing several improvements over the original model formulation. In particular, the model is now trained on vortex-averaged reaction rates of the ATLAS Chemistry and Transport Model, which enables a detailed look at individual processes and an independent validation of the different parameterizations contained in the differential equations. The training of the original Polar SWIFT model was based on fitting complete model runs to satellite observations and did not allow for this. A revised formulation of the system of differential equations is developed, which closely fits vortex-averaged reaction rates from ATLAS that represent the main chemical processes influencing ozone. In addition, a parameterization for the HNO3 change by denitrification is included. The rates of change of the concentrations of the chemical species of the Polar SWIFT model are purely chemical rates of change in the new version, whereas in the original Polar SWIFT model, they included a transport effect caused by the

Neutron polarization

International Nuclear Information System (INIS)

Firk, F.W.K.

1976-01-01

Some recent experiments involving polarized neutrons are discussed; they demonstrate how polarization studies provide information on fundamental aspects of nuclear structure that cannot be obtained from more traditional neutron studies. Until recently, neutron polarization studies tended to be limited either to very low energies or to restricted regions at higher energies, determined by the kinematics of favorable (p, vector n) and (d, vector n) reactions. With the advent of high intensity pulsed electron and proton accelerators and of beams of vector polarized deuterons, this is no longer the case. One has entered an era in which neutron polarization experiments are now being carried out, in a routine way, throughout the entire range from thermal energies to tens-of-MeV. The significance of neutron polarization studies is illustrated in discussions of a wide variety of experiments that include the measurement of T-invariance in the β-decay of polarized neutrons, a search for the effects of meson exchange currents in the photo-disintegration of the deuteron, the determination of quantum numbers of states in the fission of aligned 235 U and 237 Np induced by polarized neutrons, and the double- and triple-scattering of fast neutrons by light nuclei

Proteomic Analysis of Intact Flagella of Procyclic Trypanosoma brucei Cells Identifies Novel Flagellar Proteins with Unique Sub-localization and Dynamics*

Science.gov (United States)

Subota, Ines; Julkowska, Daria; Vincensini, Laetitia; Reeg, Nele; Buisson, Johanna; Blisnick, Thierry; Huet, Diego; Perrot, Sylvie; Santi-Rocca, Julien; Duchateau, Magalie; Hourdel, Véronique; Rousselle, Jean-Claude; Cayet, Nadège; Namane, Abdelkader; Chamot-Rooke, Julia; Bastin, Philippe

2014-01-01

Cilia and flagella are complex organelles made of hundreds of proteins of highly variable structures and functions. Here we report the purification of intact flagella from the procyclic stage of Trypanosoma brucei using mechanical shearing. Structural preservation was confirmed by transmission electron microscopy that showed that flagella still contained typical elements such as the membrane, the axoneme, the paraflagellar rod, and the intraflagellar transport particles. It also revealed that flagella severed below the basal body, and were not contaminated by other cytoskeletal structures such as the flagellar pocket collar or the adhesion zone filament. Mass spectrometry analysis identified a total of 751 proteins with high confidence, including 88% of known flagellar components. Comparison with the cell debris fraction revealed that more than half of the flagellum markers were enriched in flagella and this enrichment criterion was taken into account to identify 212 proteins not previously reported to be associated to flagella. Nine of these were experimentally validated including a 14-3-3 protein not yet reported to be associated to flagella and eight novel proteins termed FLAM (FLAgellar Member). Remarkably, they localized to five different subdomains of the flagellum. For example, FLAM6 is restricted to the proximal half of the axoneme, no matter its length. In contrast, FLAM8 is progressively accumulating at the distal tip of growing flagella and half of it still needs to be added after cell division. A combination of RNA interference and Fluorescence Recovery After Photobleaching approaches demonstrated very different dynamics from one protein to the other, but also according to the stage of construction and the age of the flagellum. Structural proteins are added to the distal tip of the elongating flagellum and exhibit slow turnover whereas membrane proteins such as the arginine kinase show rapid turnover without a detectible polarity. PMID:24741115

Proteomic analysis of intact flagella of procyclic Trypanosoma brucei cells identifies novel flagellar proteins with unique sub-localization and dynamics.

Science.gov (United States)

Subota, Ines; Julkowska, Daria; Vincensini, Laetitia; Reeg, Nele; Buisson, Johanna; Blisnick, Thierry; Huet, Diego; Perrot, Sylvie; Santi-Rocca, Julien; Duchateau, Magalie; Hourdel, Véronique; Rousselle, Jean-Claude; Cayet, Nadège; Namane, Abdelkader; Chamot-Rooke, Julia; Bastin, Philippe

2014-07-01

Cilia and flagella are complex organelles made of hundreds of proteins of highly variable structures and functions. Here we report the purification of intact flagella from the procyclic stage of Trypanosoma brucei using mechanical shearing. Structural preservation was confirmed by transmission electron microscopy that showed that flagella still contained typical elements such as the membrane, the axoneme, the paraflagellar rod, and the intraflagellar transport particles. It also revealed that flagella severed below the basal body, and were not contaminated by other cytoskeletal structures such as the flagellar pocket collar or the adhesion zone filament. Mass spectrometry analysis identified a total of 751 proteins with high confidence, including 88% of known flagellar components. Comparison with the cell debris fraction revealed that more than half of the flagellum markers were enriched in flagella and this enrichment criterion was taken into account to identify 212 proteins not previously reported to be associated to flagella. Nine of these were experimentally validated including a 14-3-3 protein not yet reported to be associated to flagella and eight novel proteins termed FLAM (FLAgellar Member). Remarkably, they localized to five different subdomains of the flagellum. For example, FLAM6 is restricted to the proximal half of the axoneme, no matter its length. In contrast, FLAM8 is progressively accumulating at the distal tip of growing flagella and half of it still needs to be added after cell division. A combination of RNA interference and Fluorescence Recovery After Photobleaching approaches demonstrated very different dynamics from one protein to the other, but also according to the stage of construction and the age of the flagellum. Structural proteins are added to the distal tip of the elongating flagellum and exhibit slow turnover whereas membrane proteins such as the arginine kinase show rapid turnover without a detectible polarity. © 2014 by The

Three-photon polarization ququarts: polarization, entanglement and Schmidt decompositions

International Nuclear Information System (INIS)

Fedorov, M V; Miklin, N I

2015-01-01

We consider polarization states of three photons, propagating collinearly and having equal given frequencies but with arbitrary distributed horizontal or vertical polarizations of photons. A general form of such states is a superposition of four basic three-photon polarization modes, to be referred to as the three-photon polarization ququarts (TPPQ). All such states can be considered as consisting of one- and two-photon parts, which can be entangled with each other. The degrees of entanglement and polarization, as well as the Schmidt decomposition and Stokes vectors of TPPQ are found and discussed. (paper)

Aloe vera enhances the innate immune response of pacu (Piaractus mesopotamicus) after transport stress and combined heat killed Aeromonas hydrophila infection.

Science.gov (United States)

Zanuzzo, Fábio S; Sabioni, Rafael E; Montoya, Luz Natalia F; Favero, Gisele; Urbinati, Elisabeth C

2017-06-01

In this study, pacu (Piaractus mesopotamicus) were fed with diets containing Aloe vera for 10 days prior to transport stress and infection with heat killed Aeromonas hydrophila. A. vera is popular around the world due to its medicinal properties, including immunostimulatory effects which was observed in this study. The results show that transport causes immunosuppression, an effect that was prevented by A. vera. Specifically, A. vera prevented reductions of both leukocyte respiratory burst and hemolytic activity of complement system caused by transport. Further, fish fed with A. vera also showed significantly higher leukocyte respiratory burst, serum lysozyme concentrations and activity of complement system 24 h after bacterial infection. Additionally, we observed that A. vera may modulate the innate response through activation of complement system during bacterial immune stimulation. In summary, A. vera extract enhanced innate immune parameters and consequently the ability of fish to cope with pathogens following transport stress. These findings show that A. vera has promise for use in aquaculture and add further evidence that medicinal herbs added to fish feed assist to prevent disease outbreaks. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polarization splitter and polarization rotator designs based on transformation optics.

Science.gov (United States)

Kwon, Do-Hoon; Werner, Douglas H

2008-11-10

The transformation optics technique is employed in this paper to design two optical devices - a two-dimensional polarization splitter and a three-dimensional polarization rotator for propagating beams. The polarization splitter translates the TM- and the TE-polarized components of an incident beam in opposite directions (i.e., shifted up or shifted down). The polarization rotator rotates the polarization state of an incoming beam by an arbitrary angle. Both optical devices are reflectionless at the entry and exit interfaces. Design details and full-wave simulation results are provided.

Polarization dynamics and polarization time of random three-dimensional electromagnetic fields

International Nuclear Information System (INIS)

Voipio, Timo; Setaelae, Tero; Shevchenko, Andriy; Friberg, Ari T.

2010-01-01

We investigate the polarization dynamics of random, stationary three-dimensional (3D) electromagnetic fields. For analyzing the time evolution of the instantaneous polarization state, two intensity-normalized polarization autocorrelation functions are introduced, one based on a geometric approach with the Poincare vectors and the other on energy considerations with the Jones vectors. Both approaches lead to the same conclusions on the rate and strength of the polarization dynamics and enable the definition of a polarization time over which the state of polarization remains essentially unchanged. For fields obeying Gaussian statistics, the two correlation functions are shown to be expressible in terms of quantities characterizing partial 3D polarization and electromagnetic coherence. The 3D degree of polarization is found to have the same meaning in the 3D polarization dynamics as the usual two-dimensional (2D) degree of polarization does with planar fields. The formalism is demonstrated with several examples, and it is expected to be useful in applications dealing with polarization fluctuations of 3D light.

Polarized electron sources

Energy Technology Data Exchange (ETDEWEB)

Prepost, R. [Univ. of Wisconsin, Madison, WI (United States)

1994-12-01

The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented.

Polarized electron sources

International Nuclear Information System (INIS)

Prepost, R.

1994-01-01

The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented

Update of the Polar SWIFT model for polar stratospheric ozone loss (Polar SWIFT version 2

Directory of Open Access Journals (Sweden)

I. Wohltmann

2017-07-01

Full Text Available The Polar SWIFT model is a fast scheme for calculating the chemistry of stratospheric ozone depletion in polar winter. It is intended for use in global climate models (GCMs and Earth system models (ESMs to enable the simulation of mutual interactions between the ozone layer and climate. To date, climate models often use prescribed ozone fields, since a full stratospheric chemistry scheme is computationally very expensive. Polar SWIFT is based on a set of coupled differential equations, which simulate the polar vortex-averaged mixing ratios of the key species involved in polar ozone depletion on a given vertical level. These species are O3, chemically active chlorine (ClOx, HCl, ClONO2 and HNO3. The only external input parameters that drive the model are the fraction of the polar vortex in sunlight and the fraction of the polar vortex below the temperatures necessary for the formation of polar stratospheric clouds. Here, we present an update of the Polar SWIFT model introducing several improvements over the original model formulation. In particular, the model is now trained on vortex-averaged reaction rates of the ATLAS Chemistry and Transport Model, which enables a detailed look at individual processes and an independent validation of the different parameterizations contained in the differential equations. The training of the original Polar SWIFT model was based on fitting complete model runs to satellite observations and did not allow for this. A revised formulation of the system of differential equations is developed, which closely fits vortex-averaged reaction rates from ATLAS that represent the main chemical processes influencing ozone. In addition, a parameterization for the HNO3 change by denitrification is included. The rates of change of the concentrations of the chemical species of the Polar SWIFT model are purely chemical rates of change in the new version, whereas in the original Polar SWIFT model, they included a transport effect

Promoting Diversity Through Polar Interdisciplinary Coordinated Education (Polar ICE)

Science.gov (United States)

McDonnell, J. D.; Hotaling, L. A.; Garza, C.; Van Dyk, P. B.; Hunter-thomson, K. I.; Middendorf, J.; Daniel, A.; Matsumoto, G. I.; Schofield, O.

2017-12-01

Polar Interdisciplinary Coordinated Education (ICE) is an education and outreach program designed to provide public access to the Antarctic and Arctic regions through polar data and interactions with the scientists. The program provides multi-faceted science communication training for early career scientists that consist of a face-to face workshop and opportunities to apply these skills. The key components of the scientist training workshop include cultural competency training, deconstructing/decoding science for non-expert audiences, the art of telling science stories, and networking with members of the education and outreach community and reflecting on communication skills. Scientists partner with educators to provide professional development for K-12 educators and support for student research symposia. Polar ICE has initiated a Polar Literacy initiative that provides both a grounding in big ideas in polar science and science communication training designed to underscore the importance of the Polar Regions to the public while promoting interdisciplinary collaborations between scientists and educators. Our ultimate objective is to promote STEM identity through professional development of scientists and educators while developing career awareness of STEM pathways in Polar science.

Polarization-independent broadband meta-holograms via polarization-dependent nanoholes.

Science.gov (United States)

Zhang, Xiaohu; Li, Xiong; Jin, Jinjin; Pu, Mingbo; Ma, Xiaoliang; Luo, Jun; Guo, Yinghui; Wang, Changtao; Luo, Xiangang

2018-05-17

Composed of ultrathin metal or dielectric nanostructures, metasurfaces can manipulate the phase, amplitude and polarization of electromagnetic waves at a subwavelength scale, which is promising for flat optical devices. In general, metasurfaces composed of space-variant anisotropic units are sensitive to the incident polarization due to the inherent polarization dependent geometric phase. Here, we implement polarization-independent broadband metasurface holograms constructed by polarization-dependent anisotropic elliptical nanoholes by elaborate design of complex amplitude holograms. The fabricated meta-hologram exhibits a polarization insensitive feature with an acceptable image quality. We verify the feasibility of the design algorithm for three-dimensional (3D) meta-holograms with simulation and the feasibility for two-dimensional (2D) meta-holograms is experimentally demonstrated at a broadband wavelength range from 405 nm to 632.8 nm. The effective polarization-independent broadband complex wavefront control with anisotropic elliptical nanoholes proposed in this paper greatly promotes the practical applications of the metasurface in technologies associated with wavefront manipulation, such as flat lens, colorful holographic displays and optical storage.

Polarization digital holographic microscopy using low-cost liquid crystal polarization rotators

Science.gov (United States)

Dovhaliuk, Rostyslav Yu

2018-02-01

Polarization imaging methods are actively used to study anisotropic objects. A number of methods and systems, such as imaging polarimeters, were proposed to measure the state of polarization of light that passed through the object. Digital holographic and interferometric approaches can be used to quantitatively measure both amplitude and phase of a wavefront. Using polarization modulation optics, the measurement capabilities of such interference-based systems can be extended to measure polarization-dependent parameters, such as phase retardation. Different kinds of polarization rotators can be used to alternate the polarization of a reference beam. Liquid crystals are used in a rapidly increasing number of different optoelectronic devices. Twisted nematic liquid crystals are widely used as amplitude modulators in electronic displays and light valves or shutter glass. Such devices are of particular interest for polarization imaging, as they can be used as polarization rotators, and due to large-scale manufacturing have relatively low cost. A simple Mach-Zehnder polarized holographic setup that uses modified shutter glass as a polarization rotator is demonstrated. The suggested approach is experimentally validated by measuring retardation of quarter-wave film.

Polarization holography

DEFF Research Database (Denmark)

Nikolova, L.; Ramanujam, P.S.

Current research into holography is concerned with applications in optically storing, retrieving, and processing information. Polarization holography has many unique properties compared to conventional holography. It gives results in high efficiency, achromaticity, and special polarization...... properties. This books reviews the research carried out in this field over the last 15 years. The authors provide basic concepts in polarization and the propagation of light through anisotropic materials, before presenting a sound theoretical basis for polarization holography. The fabrication...... and characterization of azobenzene based materials, which remain the most efficient for the purpose, is described in detail. This is followed by a description of other materials that are used in polarization holography. An in-depth description of various applications, including display holography and optical storage...

Polarized neutron spectrometer

International Nuclear Information System (INIS)

Abov, Yu.G.; Novitskij, V.V.; Alfimenkov, V.P.; Galinskij, E.M.; Mareev, Yu.D.; Pikel'ner, L.B.; Chernikov, A.N.; Lason', L.; Tsulaya, V.M.; Tsulaya, M.I.

2000-01-01

The polarized neutron spectrometer, intended for studying the interaction of polarized neutrons with nuclei and condensed media in the area of energies from thermal up to several electron-volt, is developed at the IBR-2 reactor (JINR, Dubna). Diffraction on the Co(92%)-Fe(8%) magnetized monocrystals is used for the neutron polarization and polarization analysis. The neutron polarization within the whole energy range equals ∼ 95% [ru

PolarTrack: Optical Outside-In Device Tracking that Exploits Display Polarization

DEFF Research Database (Denmark)

Rädle, Roman; Jetter, Hans-Christian; Fischer, Jonathan

2018-01-01

PolarTrack is a novel camera-based approach to detecting and tracking mobile devices inside the capture volume. In PolarTrack, a polarization filter continuously rotates in front of an off-the-shelf color camera, which causes the displays of observed devices to periodically blink in the camera feed....... The periodic blinking results from the physical characteristics of current displays, which shine polarized light either through an LC overlay to produce images or through a polarizer to reduce light reflections on OLED displays. PolarTrack runs a simple detection algorithm on the camera feed to segment...... displays and track their locations and orientations, which makes PolarTrack particularly suitable as a tracking system for cross-device interaction with mobile devices. Our evaluation of PolarTrack's tracking quality and comparison with state-of-the-art camera-based multi-device tracking showed a better...

Lunar true polar wander inferred from polar hydrogen.

Science.gov (United States)

Siegler, M A; Miller, R S; Keane, J T; Laneuville, M; Paige, D A; Matsuyama, I; Lawrence, D J; Crotts, A; Poston, M J

2016-03-24

The earliest dynamic and thermal history of the Moon is not well understood. The hydrogen content of deposits near the lunar poles may yield insight into this history, because these deposits (which are probably composed of water ice) survive only if they remain in permanent shadow. If the orientation of the Moon has changed, then the locations of the shadowed regions will also have changed. The polar hydrogen deposits have been mapped by orbiting neutron spectrometers, and their observed spatial distribution does not match the expected distribution of water ice inferred from present-day lunar temperatures. This finding is in contrast to the distribution of volatiles observed in similar thermal environments at Mercury's poles. Here we show that polar hydrogen preserves evidence that the spin axis of the Moon has shifted: the hydrogen deposits are antipodal and displaced equally from each pole along opposite longitudes. From the direction and magnitude of the inferred reorientation, and from analysis of the moments of inertia of the Moon, we hypothesize that this change in the spin axis, known as true polar wander, was caused by a low-density thermal anomaly beneath the Procellarum region. Radiogenic heating within this region resulted in the bulk of lunar mare volcanism and altered the density structure of the Moon, changing its moments of inertia. This resulted in true polar wander consistent with the observed remnant polar hydrogen. This thermal anomaly still exists and, in part, controls the current orientation of the Moon. The Procellarum region was most geologically active early in lunar history, which implies that polar wander initiated billions of years ago and that a large portion of the measured polar hydrogen is ancient, recording early delivery of water to the inner Solar System. Our hypothesis provides an explanation for the antipodal distribution of lunar polar hydrogen, and connects polar volatiles to the geologic and geophysical evolution of the Moon

Polarized proton beams

International Nuclear Information System (INIS)

Roser, T.

1995-01-01

The acceleration of polarized proton beams in circular accelerators is complicated by the presence of numerous depolarizing spin resonances. Careful and tedious minimization of polarization loss at each of these resonances allowed acceleration of polarized proton beams up to 22 GeV. It has been the hope that Siberian Snakes, which are local spin rotators inserted into ring accelerators, would eliminate these resonances and allow acceleration of polarized beams with the same ease and efficiency that is now routine for unpolarized beams. First tests at IUCF with a full Siberian Snake showed that the spin dynamics with a Snake can be understood in detail. The author now has results of the first tests of a partial Siberian Snake at the AGS, accelerating polarized protons to an energy of about 25 GeV. These successful tests of storage and acceleration of polarized proton beams open up new possibilities such as stored polarized beams for internal target experiments and high energy polarized proton colliders

Flagellation of Pseudomonas aeruginosa in newly divided cells

Science.gov (United States)

Zhao, Kun; Lee, Calvin; Anda, Jaime; Wong, Gerard

2015-03-01

For monotrichous bacteria, Pseudomonas aeruginosa, after cell division, one daughter cell inherits the old flagellum from its mother cell, and the other grows a new flagellum during or after cell division. It had been shown that the new flagellum grows at the distal pole of the dividing cell when the two daughter cells haven't completely separated. However, for those daughter cells who grow new flagella after division, it still remains unknown at which pole the new flagellum will grow. Here, by combining our newly developed bacteria family tree tracking techniques with genetic manipulation method, we showed that for the daughter cell who did not inherit the old flagellum, a new flagellum has about 90% chances to grow at the newly formed pole. We proposed a model for flagellation of P. aeruginosa.

Charge transport in non-polar and semi-polar III-V nitride heterostructures

International Nuclear Information System (INIS)

Konar, Aniruddha; Verma, Amit; Fang, Tian; Zhao, Pei; Jana, Raj; Jena, Debdeep

2012-01-01

Compared to the intense research focus on the optical properties, the transport properties in non-polar and semi-polar III-nitride semiconductors remain relatively unexplored to date. The purpose of this paper is to discuss charge-transport properties in non-polar and semi-polar orientations of GaN in a comparative fashion to what is known for transport in polar orientations. A comprehensive approach is adopted, starting from an investigation of the differences in the electronic bandstructure along different polar orientations of GaN. The polarization fields along various orientations are then discussed, followed by the low-field electron and hole mobilities. A number of scattering mechanisms that are specific to non-polar and semi-polar GaN heterostructures are identified, and their effects are evaluated. Many of these scattering mechanisms originate due to the coupling of polarization with disorder and defects in various incarnations depending on the crystal orientation. The effect of polarization orientation on carrier injection into quantum-well light-emitting diodes is discussed. This paper ends with a discussion of orientation-dependent high-field charge-transport properties including velocity saturation, instabilities and tunneling transport. Possible open problems and opportunities are also discussed. (paper)

Polarization-sensitive color in butterfly scales: polarization conversion from ridges with reflecting elements.

Science.gov (United States)

Zhang, Ke; Tang, Yiwen; Meng, Jinsong; Wang, Ge; Zhou, Han; Fan, Tongxiang; Zhang, Di

2014-11-03

Polarization-sensitive color originates from polarization-dependent reflection or transmission, exhibiting abundant light information, including intensity, spectral distribution, and polarization. A wide range of butterflies are physiologically sensitive to polarized light, but the origins of polarized signal have not been fully understood. Here we systematically investigate the colorful scales of six species of butterfly to reveal the physical origins of polarization-sensitive color. Microscopic optical images under crossed polarizers exhibit their polarization-sensitive characteristic, and micro-structural characterizations clarify their structural commonality. In the case of the structural scales that have deep ridges, the polarization-sensitive color related with scale azimuth is remarkable. Periodic ridges lead to the anisotropic effective refractive indices in the parallel and perpendicular grating orientations, which achieves form-birefringence, resulting in the phase difference of two different component polarized lights. Simulated results show that ridge structures with reflecting elements reflect and rotate the incident p-polarized light into s-polarized light. The dimensional parameters and shapes of grating greatly affect the polarization conversion process, and the triangular deep grating extends the outstanding polarization conversion effect from the sub-wavelength period to the period comparable to visible light wavelength. The parameters of ridge structures in butterfly scales have been optimized to fulfill the polarization-dependent reflection for secret communication. The structural and physical origin of polarization conversion provides a more comprehensive perspective on the creation of polarization-sensitive color in butterfly wing scales. These findings show great potential in anti-counterfeiting technology and advanced optical material design.

System for measuring the proton polarization in a polarized target

International Nuclear Information System (INIS)

Karnaukhov, I.M.; Lukhanin, A.A.; Telegin, Yu.N.; Trotsenko, V.I.; Chechetenko, V.F.

1984-01-01

The system for measuring the proton polarization in a polarized target representing the high-sensitivity nuclear magnetic resonance (NMR) is described Q-meter with series connection and a circuit for measuring system resonance characteristic is used for NMR-absorption signal recording. Measuring coil is produced of a strip conductor in order to obtain uniform system sensitivity to polarization state in all target volume and improve signal-to-noise ratio. Polarization measuring system operates ion-line with the M-6000 computer. The total measuring error for the value of free proton polarization in target taking into account the error caused by local depolarization of working substance under irradiation by high-intense photon beam is <= 6%. Long-term application of the described system for measuring the proton polarization in the LUEh-20000 accelerator target used in the pion photoproduction experiments has demonstrated its high reliability

Sources of polarized neutrons

International Nuclear Information System (INIS)

Walter, L.

1983-01-01

Various sources of polarized neutrons are reviewed. Monoenergetic source produced with unpolarized or polarized beams, white sources of polarized neutrons, production by transmissions through polarized hydrogen targets and polarized thermal neutronsare discussed, with appropriate applications included. (U.K.)

PolarHub: A Global Hub for Polar Data Discovery

Science.gov (United States)

Li, W.

2014-12-01

This paper reports the outcome of a NSF project in developing a large-scale web crawler PolarHub to discover automatically the distributed polar dataset in the format of OGC web services (OWS) in the cyberspace. PolarHub is a machine robot; its goal is to visit as many webpages as possible to find those containing information about polar OWS, extract this information and store it into the backend data repository. This is a very challenging task given huge data volume of webpages on the Web. Three unique features was introduced in PolarHub to make it distinctive from earlier crawler solutions: (1) a multi-task, multi-user, multi-thread support to the crawling tasks; (2) an extensive use of thread pool and Data Access Object (DAO) design patterns to separate persistent data storage and business logic to achieve high extendibility of the crawler tool; (3) a pattern-matching based customizable crawling algorithm to support discovery of multi-type geospatial web services; and (4) a universal and portable client-server communication mechanism combining a server-push and client pull strategies for enhanced asynchronous processing. A series of experiments were conducted to identify the impact of crawling parameters to the overall system performance. The geographical distribution pattern of all PolarHub identified services is also demonstrated. We expect this work to make a major contribution to the field of geospatial information retrieval and geospatial interoperability, to bridge the gap between data provider and data consumer, and to accelerate polar science by enhancing the accessibility and reusability of adequate polar data.

Polarization extinction ratio of the polarization crosstalk caused by point pressure force in the polarization-maintaining fiber

Science.gov (United States)

Mukhtubayev, Azamat B.; Aksarin, Stanislav M.; Strigalev, Vladimir E.

2017-11-01

A study of the orthogonal polarization modes crosstalk changes in the point of different mechanical actions (pressure force) in the polarization-maintaining fiber with straining elliptical cladding is presented. It was found that by increasing of the pressure force the polarization extinction ratio increases nonlinearly. Also revealed the dependence of the extinction coefficient and the angle between vector of the mechanical action and polarization axes of the test fiber, which leads to change the extinction coefficient variable from -57 dB to -25 dB under the pressure force of 0.7 N. Also it was found that the cross angle of the fiber axes doesn't influence on the extinction ratio value of the mechanical induced polarization crosstalk.

Polarized secondary radioactive beams

International Nuclear Information System (INIS)

Zaika, N.I.

1992-01-01

Three methods of polarized radioactive nuclei beam production: a) a method nuclear interaction of the non-polarized or polarized charged projectiles with target nuclei; b) a method of polarization of stopped reaction radioactive products in a special polarized ion source with than following acceleration; c) a polarization of radioactive nuclei circulating in a storage ring are considered. Possible life times of the radioactive ions for these methods are determined. General schemes of the polarization method realizations and depolarization problems are discussed

Scattering of polarized electrons from polarized targets: Coincidence reactions and prescriptions for polarized half-off-shell single-nucleon cross sections

International Nuclear Information System (INIS)

Caballero, J.A.; Massachusetts Inst. of Tech., Cambridge, MA; Donnelly, T.W.; Massachusetts Inst. of Tech., Cambridge, MA; Poulis, G.I.; Massachusetts Inst. of Tech., Cambridge, MA

1993-01-01

Coincidence reactions of the type vector A( vector e, e'N)B involving the scattering of polarized electrons from polarized targets are discussed within the context of the plane-wave impulse approximation. Prescriptions are developed for polarized half-off single-nucleon cross sections; the different prescriptions are compared for typical quasi-free kinematics. Illustrative results are presented for coincidence polarized electron scattering from typical polarized nuclei. (orig.)

Ortho-Babinet polarization-interrogating filter: an interferometric approach to polarization measurement.

Science.gov (United States)

Van Delden, Jay S

2003-07-15

A novel, interferometric, polarization-interrogating filter assembly and method for the simultaneous measurement of all four Stokes parameters across a partially polarized irradiance image in a no-moving-parts, instantaneous, highly sensitive manner is described. In the reported embodiment of the filter, two spatially varying linear retarders and a linear polarizer comprise an ortho-Babinet, polarization-interrogating (OBPI) filter. The OBPI filter uniquely encodes the incident ensemble of electromagnetic wave fronts comprising a partially polarized irradiance image in a controlled, deterministic, spatially varying manner to map the complete state of polarization across the image to local variations in a superposed interference pattern. Experimental interferograms are reported along with a numerical simulation of the method.

Coronal Polarization of Pseudostreamers and the Solar Polar Field Reversal

Science.gov (United States)

Rachmeler, L. A.; Guennou, C.; Seaton, D. B.; Gibson, S. E.; Auchere, F.

2016-01-01

The reversal of the solar polar magnetic field is notoriously hard to pin down due to the extreme viewing angle of the pole. In Cycle 24, the southern polar field reversal can be pinpointed with high accuracy due to a large-scale pseudostreamer that formed over the pole and persisted for approximately a year. We tracked the size and shape of this structure with multiple observations and analysis techniques including PROBA2/SWAP EUV images, AIA EUV images, CoMP polarization data, and 3D tomographic reconstructions. We find that the heliospheric field reversed polarity in February 2014, whereas in the photosphere, the last vestiges of the previous polar field polarity remained until March 2015. We present here the evolution of the structure and describe its identification in the Fe XII 1074nm coronal emission line, sensitive to the Hanle effect in the corona.

Experiments with Fermilab polarized proton and polarized antiproton beams

International Nuclear Information System (INIS)

Yokosawa, A.

1990-01-01

We summarize activities concerning the Fermilab polarized beams. They include a brief description of the polarized-beam facility, measurements of beam polarization by polarimeters, asymmetry measurements in the π degree production at high p perpendicular and in the Λ (Σ degree), π ± , π degree production at large x F , and Δσ L (pp, bar pp) measurements. 18 refs

Recent advance in polar seismology: Global impact of the International Polar Year

Science.gov (United States)

Kanao, Masaki; Zhao, Dapeng; Wiens, Douglas A.; Stutzmann, Éléonore

2015-03-01

The most exciting initiative for the recent polar studies was the International Polar Year (IPY) in 2007-2008. The IPY has witnessed a growing community of seismologists who have made considerable efforts to acquire high-quality data in polar regions. It also provided an excellent opportunity to make significant advances in seismic instrumentation of the polar regions to achieve scientific targets involving global issues. Taking these aspects into account, we organize and publish a special issue in Polar Science on the recent advance in polar seismology and cryoseismology as fruitful achievements of the IPY.

Study of excess carrier dynamics in polar, semi-polar, and non-polar (In,Ga)N epilayers and QWs

Energy Technology Data Exchange (ETDEWEB)

Aleksiejunas, R. [Institute of Applied Research, Vilnius University, Sauletekio Ave. 9-III, 10222 Vilnius (Lithuania); Laser Research Center, Vilnius University, Sauletekio Ave. 10, 10222 Vilnius (Lithuania); Lubys, L.; Jarasiunas, K. [Institute of Applied Research, Vilnius University, Sauletekio Ave. 9-III, 10222 Vilnius (Lithuania); Vengris, M. [Laser Research Center, Vilnius University, Sauletekio Ave. 10, 10222 Vilnius (Lithuania); Wernicke, T.; Hoffmann, V.; Netzel, C.; Knauer, A.; Weyers, M. [Ferdinand-Braun-Institut, Leibniz-Institut fuer Hoechstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12498 Berlin (Germany); Kneissl, M. [Ferdinand-Braun-Institut, Leibniz-Institut fuer Hoechstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12498 Berlin (Germany); Institute of Solid State Physics, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany)

2011-07-15

We studied carrier recombination and diffusion in GaN/sapphire templates, (In,Ga)N layers, and (In,Ga)N quantum well structures oriented along the polar [0001], semi-polar [11-22], and non-polar [11-20] orientations by means of light induced transient grating, differential transmission, and photoluminescence optical techniques. We show that the lifetime of excess carriers drops by orders of magnitude when changing the orientation from polar to non-polar, both in GaN templates and (In,Ga)N layers. We attribute the shorter lifetime to carrier trapping by extended structural defects that are more abundant in non-polar grown samples. In addition, we observe pronounced carrier localization effects in the semi- and non-polar layers. We show that thick (In,Ga)N layers inherit the properties of the GaN templates. However, the thin quantum well structures show a lower carrier trapping activity. So, a better electrical quality can be assumed as compared to the thick (In,Ga)N layers. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Polarized targets and beams

International Nuclear Information System (INIS)

Meyer, W.

1985-01-01

First the experimental situation of the single-pion photoproduction and the photodisintegration of the deuteron is briefly discussed. Then a description of the Bonn polarization facilities is given. The point of main effort is put on the polarized target which plays a vital role in the program. A facility for photon induced double polarization experiments at ELSA will be presented in section 4. Properties of a tensor polarized deuteron target are discussed in section 5. The development in the field of polarized targets, especially on new target materials, enables a new generation of polarized target experiments with (polarized) electrons. Some comments on the use of a polarized target in combination with electron beams will be discussed in section 6. Electron deuteron scattering from a tensor polarized deuteron target is considered and compared with other experimental possibilities. (orig./HSI)

Reduction of coating induced polarization aberrations by controlling the polarization state variation

International Nuclear Information System (INIS)

Li, Yanghui; Shen, Weidong; Zheng, Zhenrong; Zhang, Yueguang; Liu, Xu; Hao, Xiang

2011-01-01

The mechanism of coating induced polarization state variation is analysed by the Jones matrix. Pauli spin matrices are used to establish the relationship between coating induced polarization state variation and polarization aberrations. To reduce coating induced polarization aberrations, we propose that δ = 0 and T s = T p at arbitrary incident angle should be appended as two additional optimization goals of optical coating design when the requirements of transmittance are met. Two typical anti-reflection (AR) coatings are designed and the polarization state variation induced by them is simulated. The MTF (modulation transfer function) calculated by polarization ray tracing is applied to evaluate the polarization aberrations of the practical lithography objective system with the two AR coatings. All the obtained results show that the coating induced polarization aberrations can be reduced by optimizing the angle dependent properties of the optical coating without additional optical elements

Effect of 3D Polarization profiles on polarization measurements and colliding beam experiments

Energy Technology Data Exchange (ETDEWEB)

Fischer, W.; Bazilevsky, A.

2011-08-18

The development of polarization profiles are the primary reason for the loss of average polarization. Polarization profiles have been parametrized with a Gaussian distribution. We derive the effect of 3-dimensional polarization profiles on the measured polarization in polarimeters, as well as the observed polarization and the figure of merit in single and double spin experiments. Examples from RHIC are provided. The Relativistic Heavy Ion Collider (RHIC) is the only collider of spin polarized protons. During beam acceleration and storage profiles of the polarization P develop, which affect the polarization measured in a polarimeter, and the polarization and figure of merit (FOM) in colliding beam experiments. We calculate these for profiles in all dimensions, and give examples for RHIC. Like in RHIC we call the two colliding beams Blue and Yellow. We use the overbar to designate intensity-weighted averages in polarimeters (e.g. {bar P}), and angle brackets to designate luminosity-weighted averages in colliding beam experiments (e.g.

).

Effect of 3D Polarization profiles on polarization measurements and colliding beam experiments

International Nuclear Information System (INIS)

Fischer, W.; Bazilevsky, A.

2011-01-01

The development of polarization profiles are the primary reason for the loss of average polarization. Polarization profiles have been parametrized with a Gaussian distribution. We derive the effect of 3-dimensional polarization profiles on the measured polarization in polarimeters, as well as the observed polarization and the figure of merit in single and double spin experiments. Examples from RHIC are provided. The Relativistic Heavy Ion Collider (RHIC) is the only collider of spin polarized protons. During beam acceleration and storage profiles of the polarization P develop, which affect the polarization measured in a polarimeter, and the polarization and figure of merit (FOM) in colliding beam experiments. We calculate these for profiles in all dimensions, and give examples for RHIC. Like in RHIC we call the two colliding beams Blue and Yellow. We use the overbar to designate intensity-weighted averages in polarimeters (e.g. (bar P)), and angle brackets to designate luminosity-weighted averages in colliding beam experiments (e.g. ).

Nuclear polarization and neutrons

International Nuclear Information System (INIS)

Glaettli, H.

1985-01-01

Different possibilities for the use of polarized nuclei in thermal neutron scattering on condensed matter are reviewed. Highly polarized nuclei are the starting point for studying dipolar magnetic order. Systematic measurement of spin-dependent scattering lengths is possible on samples with polarized nuclei. Highly polarized hydrogen should help to unravel complicated structures in chemistry and biology. The use of polarized proton targets as an energy-independent neutron polarizer in the thermal and epithermal region should be considered afresh. (author)

NUCLEON POLARIZATION IN 3-BODY MODELS OF POLARIZED LI-6

NARCIS (Netherlands)

SCHELLINGERHOUT, NW; KOK, LP; COON, SA; ADAM, RM

1993-01-01

Just as He-3 --> can be approximately characterized as a polarized neutron target, polarized Li-6D has been advocated as a good isoscalar nuclear target for the extraction of the polarized gluon content of the nucleon. The original argument rests upon a presumed ''alpha + deuteron'' picture of Li-6,

Superconducting polarizing magnet for a movable polarized target

International Nuclear Information System (INIS)

Anishchenko, N.G.; Bartenev, V.D.; Blinov, N.A.

1998-01-01

The superconducting polarizing magnet was constructed for the JINR (Dubna) movable polarized target (MPT) with working volume 200 mm long and 30 mm in diameter. The magnet provides a polarizing magnetic field up to 6 T in the centre with the uniformity of 4.5 x 10 -4 in the working volume of the target. The magnet contains a main solenoidal winding 558 mm long and 206/144 mm in diameters, and compensating and correcting winding placed at its ends. The windings are made of a NbTi wire, impregnated with the epoxy resin and placed in the horizontal cryostat. The diameter of the 'warm' aperture of the magnet cryostat is 96 mm. The design and technology of the magnet winding are described. Results of the magnetic field map measurements, using a NMR-magnetometer are given. A similar magnet constructed at DAPNIA, CEA/Saclay (France), represented a model for the present development. The MPT array is installed in the beam line of polarized neutrons produced by break-up of polarized deuterons extracted from the synchrophasotron of the Laboratory of High Energies (LHE), JINR (Dubna)

CMB polarization at large angular scales: Data analysis of the POLAR experiment

International Nuclear Information System (INIS)

O'Dell, Christopher W.; Keating, Brian G.; Oliveira-Costa, Angelica de; Tegmark, Max; Timbie, Peter T.

2003-01-01

The coming flood of cosmic microwave background (CMB) polarization experiments, spurred by the recent detection of CMB polarization by the DASI and WMAP instruments, will be confronted by many new analysis tasks specific to polarization. For the analysis of CMB polarization data sets, the devil is truly in the details. With this in mind, we present details of the data analysis for the POLAR experiment, which recently led to the tightest upper limits on the polarization of the cosmic microwave background radiation at large angular scales. We discuss the data selection process, map-making algorithms, offset removal, and likelihood analysis which were used to find upper limits on the polarization. Stated using the modern convention for reporting CMB Stokes parameters, these limits are 5.0 μK on both E- and B-type polarization at 95% confidence. Finally, we discuss simulations used to test our analysis techniques and to probe the fundamental limitations of the experiment

Few-body experiments with polarized beams and polarized targets

International Nuclear Information System (INIS)

Simmons, J.E.

1983-01-01

A survey is presented concerning recent polarization experiments in the elastic p-d, p- 3 He, and p- 4 He systems. Mention is made of selected neutron experiments. The nominal energy range is 10 to 1000 MeV. Recent results and interpretations of the p-d system near 10 MeV are discussed. New experiments on the energy dependence of back angle p-d tensor polarization are discussed with respect to resolution of discrepancies and difficulty of theoretical interpretation. Progress is noted concerning multiple scattering interpretation of forward p-d deuteron polarization. Some new results are presented concerning the p- 3 He system and higher energy p- 4 He polarization experiments. 52 references

Long-period polar rain variations, solar wind and hemispherically symmetric polar rain

International Nuclear Information System (INIS)

Makita, K.; Meng, C.

1987-01-01

On the basic of electron data obtained by the Defense Meteorological Satellite Program (DMSP) F2 satellite the long-period variations of the polar rain flux are examined for four consecutive solar rotations. It is clearly demonstrated that the asymmetric enhancement of the polar rain flux is strongly controlled by the sector structure of the interplanetary magnetic field (IMF). However, the orbit-to-orbit and day-to-day variations of the polar rain flux are detected even during a very stable sector period, and the polar rain flux does not have any clear relationship to the magnitude of the IMF B/sub x/ or B/sub y/. Thus the polarity of B/sub x/ controls only the accessibility of a polar region. It is also noticed that the intensity of polar rain fluxes does not show any relationship to the density of the solar wind, suggesting that the origin of the polar rain electrons is different from the commonly observed part of the solar wind electron distribution function. In addition to the asymmetric polar rain distribution, increasing polar rain fluxes of similar high intensity are sometimes detected over both polar caps. An examination of more than 1 year's data from the DMSP F2 and F4 satellites shows that simultaneous intense uniform precipitations (>10 7 electrons/cm 2 s sr) over both polar caps are not coincidental; it also shows that the spectra are similar. The occurrence of hemispherically symmetric events is not common. They generally are observed after an IMF sector transition period, during unstable periods in the sector structure, and while the solar wind density is high. copyright American Geophysical Union 1987

Degree of polarization and source counts of faint radio sources from Stacking Polarized intensity

International Nuclear Information System (INIS)

Stil, J. M.; George, S. J.; Keller, B. W.; Taylor, A. R.

2014-01-01

We present stacking polarized intensity as a means to study the polarization of sources that are too faint to be detected individually in surveys of polarized radio sources. Stacking offers not only high sensitivity to the median signal of a class of radio sources, but also avoids a detection threshold in polarized intensity, and therefore an arbitrary exclusion of sources with a low percentage of polarization. Correction for polarization bias is done through a Monte Carlo analysis and tested on a simulated survey. We show that the nonlinear relation between the real polarized signal and the detected signal requires knowledge of the shape of the distribution of fractional polarization, which we constrain using the ratio of the upper quartile to the lower quartile of the distribution of stacked polarized intensities. Stacking polarized intensity for NRAO VLA Sky Survey (NVSS) sources down to the detection limit in Stokes I, we find a gradual increase in median fractional polarization that is consistent with a trend that was noticed before for bright NVSS sources, but is much more gradual than found by previous deep surveys of radio polarization. Consequently, the polarized radio source counts derived from our stacking experiment predict fewer polarized radio sources for future surveys with the Square Kilometre Array and its pathfinders.

Polarization developments

International Nuclear Information System (INIS)

Prescott, C.Y.

1993-07-01

Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist

Geographical Income Polarization

DEFF Research Database (Denmark)

Azhar, Hussain; Jonassen, Anders Bruun

inter municipal income inequality. Counter factual simulations show that rising property prices to a large part explain the rise in polarization. One side-effect of polarization is tendencies towards a parallel polarization of residence location patterns, where low skilled individuals tend to live...

Perceiving polarization with the naked eye: characterization of human polarization sensitivity

Science.gov (United States)

Temple, Shelby E.; McGregor, Juliette E.; Miles, Camilla; Graham, Laura; Miller, Josie; Buck, Jordan; Scott-Samuel, Nicholas E.; Roberts, Nicholas W.

2015-01-01

Like many animals, humans are sensitive to the polarization of light. We can detect the angle of polarization using an entoptic phenomenon called Haidinger's brushes, which is mediated by dichroic carotenoids in the macula lutea. While previous studies have characterized the spectral sensitivity of Haidinger's brushes, other aspects remain unexplored. We developed a novel methodology for presenting gratings in polarization-only contrast at varying degrees of polarization in order to measure the lower limits of human polarized light detection. Participants were, on average, able to perform the task down to a threshold of 56%, with some able to go as low as 23%. This makes humans the most sensitive vertebrate tested to date. Additionally, we quantified a nonlinear relationship between presented and perceived polarization angle when an observer is presented with a rotatable polarized light field. This result confirms a previous theoretical prediction of how uniaxial corneal birefringence impacts the perception of Haidinger's brushes. The rotational dynamics of Haidinger's brushes were then used to calculate corneal retardance. We suggest that psychophysical experiments, based upon the perception of polarized light, are amenable to the production of affordable technologies for self-assessment and longitudinal monitoring of visual dysfunctions such as age-related macular degeneration. PMID:26136441

Measurement of the polarized neutron---polarized 3He total cross section

International Nuclear Information System (INIS)

Keith, C.D.; Gould, C.R.; Haase, D.G.; Seely, M.L.; Huffman, P.R.; Roberson, N.R.; Tornow, W.; Wilburn, W.S.

1995-01-01

The first measurements of polarized neutron--polarized 3 He scattering in the few MeV energy region are reported. The total cross section difference Δσ T for transversely polarized target and beam has been measured for neutron energies between 1.9 and 7.5 MeV. Comparison is made to predictions of Δσ T using various descriptions of the 4 He continuum. A brute-force polarized target of solid 3 He has been developed for these measurements. The target is 4.3x10 22 atoms/cm 2 thick and is polarized to 38% at 7 Telsa and 12 mK. copyright 1995 American Institute of Physics

Scattering with polarized neutrons

International Nuclear Information System (INIS)

Schweizer, J.

2007-01-01

In the history of neutron scattering, it was shown very soon that the use of polarized neutron beams brings much more information than usual scattering with unpolarized neutrons. We shall develop here the different scattering methods that imply polarized neutrons: 1) polarized beams without polarization analysis, the flipping ratio method; 2) polarized beams with a uniaxial polarization analysis; 3) polarized beams with a spherical polarization analysis. For all these scattering methods, we shall give examples of the physical problems which can been solved by these methods, particularly in the field of magnetism: investigation of complex magnetic structures, investigation of spin or magnetization densities in metals, insulators and molecular compounds, separation of magnetic and nuclear scattering, investigation of magnetic properties of liquids and amorphous materials and even, for non magnetic material, separation between coherent and incoherent scattering. (author)

Dynamically polarized hydrogen target as a broadband, wavelength-independent thermal neutron spin polarizer

International Nuclear Information System (INIS)

Zhao Jinkui; Garamus, Vasil M.; Mueller, Wilhelm; Willumeit, Regine

2005-01-01

A hydrogen-rich sample with dynamically polarized hydrogen nuclei was tested as a wavelength-independent neutron transmission spin polarizer. The experiment used a modified setup of the dynamic nuclear polarization target station at the GKSS research center. The standard solvent sample at the GKSS DNP station was used. It is 2.8mm thick and consists of 43.4wt% water, 54.6wt% glycerol, and 2wt% of EHBA-Cr(v) complex. The wavelength of the incident neutrons for the transmission experiment was λ=8.1A with Δλ/λ=10%. The polarization of neutron beam after the target sample was analyzed with a supermirror analyzer. A neutron polarization of -52% was achieved at the hydrogen polarization of -69%. Further experiments will test the feasibility of other hydrogen-rich materials, such as methane, as the polarizer. A theoretical calculation shows that a polarized methane target would allow over 95% neutron polarizations with more than 30% transmission

Possibility of determining gluon polarization via polarized top pairs in gamma-proton scattering

International Nuclear Information System (INIS)

Atag, S.; Billur, A.A.

2009-01-01

We study the possibility for directly measuring the polarized gluon distribution in the process γp→t-bar t. It is shown that polarization asymmetry of the final top quarks is proportional to the gluon polarization. With available energy and luminosity, the collision of a polarized proton beam and a Compton backscattered photon beam can create polarized top quarks which carry the spin information of the process. Energy dependence and angular distributions of the polarization asymmetry of the top pairs has been discussed including statistical uncertainty.

Material and device studies for the development of ultra-violet light emitting diodes (UV-LEDS) along polar, non-polar and semi-polar directions

Science.gov (United States)

Chandrasekaran, Ramya

Over the past few years, significant effort was dedicated to the development of ultraviolet light emitting diodes (UV-LEDs) for a variety of applications. Such applications include chemical and biological detection, water purification and solid-state lighting. III-Nitride LEDs based on multiple quantum wells (MQWs) grown along the conventional [0001] (polar) direction suffer from the quantum confined Stark effect (QCSE), due to the existence of strong electric fields that arise from spontaneous and piezoelectric polarization. Thus, there is strong motivation to develop MQW-based III-nitride LED structures grown along non-polar and semi-polar directions. The goal of this dissertation is to develop UV-LEDs along the [0001] polar and [11 2¯ 0] non-polar directions by the method of Molecular Beam Epitaxy (MBE). The polar and non-polar LEDs were grown on the C-plane and R-plane sapphire substrates respectively. This work is a combination of materials science studies related to the nucleation, growth and n- and p-type doping of III-nitride films on these two substrates, as well as device studies related to fabrication and characterization of UV-LEDs. It was observed that the crystallographic orientation of the III-nitride films grown on R-plane sapphire depends strongly on the kinetic conditions of growth of the Aluminum Nitride (AIN) buffer. Specifically, growth of the AIN buffer under group III-rich conditions leads to nitride films having the (11 2¯ 0) non polar planes parallel to the sapphire surface, while growth of the buffer under nitrogen rich conditions leads to nitride films with the (11 2¯ 6) semi-polar planes parallel to the sapphire surface. The electron concentration and mobility for the films grown along the polar, non-polar and semi-polar directions were investigated. P-type doping of Gallium Nitride (GaN) films grown on the nonpolar (11 2¯ 0) plane do not suffer from polarity inversion and thus the material was doped p-type with a hole concentration

Peculiarities of annihilation of polarized positronium in polarized media

International Nuclear Information System (INIS)

Silenko, A.Ya.

2005-01-01

Features of positronium annihilation (PA) in polarized media are investigated. Strong exchange interaction with nonpaired electrons of paramagnetic atoms essentially accelerates the PA in comparison with annihilation of free positrons. The value of the spin projection on the direction of polarized nonpaired electrons has essential effect on the orthopositronium lifetime and on the width of the gamma spectrum annihilation line. It is shown that these features of PA permit to use it for studying the paramagnetic polarization [ru

Angular distribution coefficients for γ-ray polarization produced in polarized capture reactions

International Nuclear Information System (INIS)

Wulf, E.A.; Guillemette, J.; Weller, H.R.; Seyler, R.G.

1999-01-01

The previous publications have dealt with the angular momentum formalism of both linear and circularly polarized photons in (γ, x) reactions on both polarized and unpolarized targets, and the inverse (capture) reactions initiated by polarized beams. In the present work, utilizing the general formalism of Welton, the authors deal with the linear polarization of the γ-rays which are produced in capture reactions on unpolarized targets, including the possibility of having incident polarized spin 1/2 projectiles. These capture reactions are denoted by a(rvec x, rvec L)c, where rvec x is the incident polarized spin 1/2 projectile and rvec L represents the outgoing polarized γ-ray. They present here the formalism in a convenient form, display a sample table of coefficients, and illustrate its use by means of several examples. A FORTRAN code will be made available for generating similar coefficients for other reactions

Polarization effects. Volume 2

Energy Technology Data Exchange (ETDEWEB)

Courant, E.

1981-01-01

The use of polarized proton beams in ISABELLE is important for several general reasons: (1) With a single longitudinally polarized proton beam, effects involving parity violation can be identified and hence processes involving weak interactions can be separated from those involving strong and electromagnetic interactions. (2) Spin effects are important in the strong interactions and can be useful for testing QCD. The technique for obtaining polarized proton beams in ISABELLE appears promising, particularly in view of the present development of a polarized proton beam for the AGS. Projections for the luminosity in ISABELLE for collisions of polarized protons - one or both beams polarized with longitudinal or transverse polarization - range from 1/100 to 1 times the luminosity for unpolarized protons.

Instrumentation with polarized neutrons

International Nuclear Information System (INIS)

Boeni, P.; Muenzer, W.; Ostermann, A.

2009-01-01

Neutron scattering with polarization analysis is an indispensable tool for the investigation of novel materials exhibiting electronic, magnetic, and orbital degrees of freedom. In addition, polarized neutrons are necessary for neutron spin precession techniques that path the way to obtain extremely high resolution in space and time. Last but not least, polarized neutrons are being used for fundamental studies as well as very recently for neutron imaging. Many years ago, neutron beam lines were simply adapted for polarized beam applications by adding polarizing elements leading usually to unacceptable losses in neutron intensity. Recently, an increasing number of beam lines are designed such that an optimum use of polarized neutrons is facilitated. In addition, marked progress has been obtained in the technology of 3 He polarizers and the reflectivity of large-m supermirrors. Therefore, if properly designed, only factors of approximately 2-3 in neutron intensity are lost. It is shown that S-benders provide neutron beams with an almost wavelength independent polarization. Using twin cavities, polarized beams with a homogeneous phase space and P>0.99 can be produced without significantly sacrificing intensity. It is argued that elliptic guides, which are coated with large m polarizing supermirrors, provide the highest flux.

Feasibility studies of a polarized positron source based on the Bremsstrahlung of polarized electrons

International Nuclear Information System (INIS)

Dumas, J.

2011-09-01

The nuclear and high-energy physics communities have shown a growing interest in the availability of high current, highly-polarized positron beams. A sufficiently energetic polarized photon or lepton incident on a target may generate, via Bremsstrahlung and pair creation within a solid target foil, electron-positron pairs that should carry some fraction of the initial polarization. Recent advances in high current (> 1 mA) spin polarized electron sources at Jefferson Lab offer the perspective of creating polarized positrons from a low energy electron beam. This thesis discusses polarization transfer from electrons to positrons in the perspective of the design optimization of a polarized positron source. The PEPPo experiment, aiming at a measurement of the positron polarization from a low energy (< 10 MeV) highly spin polarized electron beam is discussed. A successful demonstration of this technique would provide an alternative scheme for the production of low energy polarized positrons and useful information for the optimization of the design of polarized positron sources in the sub-GeV energy range. (author)

Dispersing surface-modified imogolite nanotubes in polar and non-polar solvents

Science.gov (United States)

Li, Ming; Brant, Jonathan A.

2018-02-01

Furthering the development of nanocomposite structures, namely membranes for water treatment applications, requires that methods be developed to ensure nanoparticle dispersion in polar and non-polar solvents, as both are widely used in associated synthesis techniques. Here, we report on a two-step method to graft polyvinylpyrrolidone (PVP), and a one-step method for octadecylphosphonic acid (OPA), onto the outer surfaces of imogolite nanotubes. The goal of these approaches was to improve and maintain nanotube dispersion in polymer compatible polar and non-polar solvents. The PVP coating modified the imogolite surface charge from positive to weakly negative at pH ≤ 9; the OPA made it weakly positive at acidic pH values to negative at pH ≥ 7. The PVP surface coating stabilized the nanotubes through steric hindrance in polar protic, dipolar aprotic, and chloroform. In difference to the PVP, the OPA surface coating allowed the nanotubes to be dispersed in n-hexane and chloroform, but not in the polar solvents. The lack of miscibility in the polar solvents, as well as the better dispersion in n-hexane, was attributed to the stronger hydrophobicity of the OPA polymer relative to the PVP. [Figure not available: see fulltext.

Modeling optical and UV polarization of AGNs. IV. Polarization timing

Science.gov (United States)

Rojas Lobos, P. A.; Goosmann, R. W.; Marin, F.; Savić, D.

2018-03-01

Context. Optical observations cannot resolve the structure of active galactic nuclei (AGN), and a unified model for AGN was inferred mostly from indirect methods, such as spectroscopy and variability studies. Optical reverberation mapping allowed us to constrain the spatial dimension of the broad emission line region and thereby to measure the mass of supermassive black holes. Recently, reverberation was also applied to the polarized signal emerging from different AGN components. In principle, this should allow us to measure the spatial dimensions of the sub-parsec reprocessing media. Aim. We conduct numerical modeling of polarization reverberation and provide theoretical predictions for the polarization time lag induced by different AGN components. The model parameters are adjusted to the observational appearance of the Seyfert 1 galaxy NGC 4151. Methods: We modeled scattering-induced polarization and tested different geometries for the circumnuclear dust component. Our tests included the effects of clumpiness and different dust prescriptions. To further extend the model, we also explored the effects of additional ionized winds stretched along the polar direction, and of an equatorial scattering ring that is responsible for the polarization angle observed in pole-on AGN. The simulations were run using a time-dependent version of the STOKES code. Results: Our modeling confirms the previously found polarization characteristics as a function of the observer`s viewing angle. When the dust adopts a flared-disk geometry, the lags reveal a clear difference between type 1 and type 2 AGN. This distinction is less clear for a torus geometry where the time lag is more sensitive to the geometry and optical depth of the inner surface layers of the funnel. The presence of a scattering equatorial ring and ionized outflows increased the recorded polarization time lags, and the polar outflows smooths out dependence on viewing angle, especially for the higher optical depth of the

Study on polarized optical flow algorithm for imaging bionic polarization navigation micro sensor

Science.gov (United States)

Guan, Le; Liu, Sheng; Li, Shi-qi; Lin, Wei; Zhai, Li-yuan; Chu, Jin-kui

2018-05-01

At present, both the point source and the imaging polarization navigation devices only can output the angle information, which means that the velocity information of the carrier cannot be extracted from the polarization field pattern directly. Optical flow is an image-based method for calculating the velocity of pixel point movement in an image. However, for ordinary optical flow, the difference in pixel value as well as the calculation accuracy can be reduced in weak light. Polarization imaging technology has the ability to improve both the detection accuracy and the recognition probability of the target because it can acquire the extra polarization multi-dimensional information of target radiation or reflection. In this paper, combining the polarization imaging technique with the traditional optical flow algorithm, a polarization optical flow algorithm is proposed, and it is verified that the polarized optical flow algorithm has good adaptation in weak light and can improve the application range of polarization navigation sensors. This research lays the foundation for day and night all-weather polarization navigation applications in future.

Design and simulation of a novel circularly polarized antenna with polarization reconfigurable characteristics

Directory of Open Access Journals (Sweden)

Zhang Hai

2016-01-01

Full Text Available A novel circularly polarized antenna with polarization reconfigurable characteristics was designed using co-simulation of Ansoft HFSS and Designer software. It consists of a dual-polarized antenna and phase switching network which act as the feed network for the dual-polarized antenna. The phase switching network was designed based on a Wilkinson power divider, where the output port was connected with SPDT to form a switching network. By controlling the SPDT state-off / on, the phase difference of the two ports could be alternated, which generated the orthogonal modes between the two ports of dual-polarized antenna. So that Left-hand circular polarization (LHCP and Right-hand circular polarization (RHCP could be achieved. The simulation shown that reflection coefficient was less than -12 dB and the axial ratio was below 3 dB between 1.8 GHz and 2.4 GHz with polarization reconfigurable characteristics.

VIIRS-J1 Polarization Narrative

Science.gov (United States)

Waluschka, Eugene; McCorkel, Joel; McIntire, Jeff; Moyer, David; McAndrew, Brendan; Brown, Steven W.; Lykke, Keith; Butler, James; Meister, Gerhard; Thome, Kurtis J.

2015-01-01

The VIS/NIR bands polarization sensitivity of Joint Polar Satellite Sensor 1 (JPSS1) Visible/Infrared Imaging Radiometer Suite (VIIRS) instrument was measured using a broadband source. While polarization sensitivity for bands M5-M7, I1, and I2 was less than 2.5%, the maximum polarization sensitivity for bands M1, M2, M3, and M4 was measured to be 6.4%, 4.4%, 3.1%, and 4.3%, respectively with a polarization characterization uncertainty of less than 0.3%. A detailed polarization model indicated that the large polarization sensitivity observed in the M1 to M4 bands was mainly due to the large polarization sensitivity introduced at the leading and trailing edges of the newly manufactured VISNIR bandpass focal plane filters installed in front of the VISNIR detectors. This was confirmed by polarization measurements of bands M1 and M4 bands using monochromatic light. Discussed are the activities leading up to and including the instruments two polarization tests, some discussion of the polarization model and the model results, the role of the focal plane filters, the polarization testing of the Aft-Optics-Assembly, the testing of the polarizers at Goddard and NIST and the use of NIST's T-SIRCUS for polarization testing and associated analyses and results.

Polarization of Be stars

International Nuclear Information System (INIS)

Johns, M.W.

1975-01-01

Linear polarization of starlight may be produced by electron scattering in the extended atmospheres of early type stars. Techniques are investigated for the measurement and interpretation of this polarization. Polarimetric observations were made of twelve visual double star systems in which at least one member was a B type star as a means of separating the intrinsic stellar polarization from the polarization produced in the interstellar medium. Four of the double stars contained a Be star. Evidence for intrinsic polarization was found in five systems including two of the Be systems, one double star with a short period eclipsing binary, and two systems containing only normal early type stars for which emission lines have not been previously reported. The interpretation of these observations in terms of individual stellar polarizations and their wavelength dependence is discussed. The theoretical basis for the intrinsic polarization of early type stars is explored with a model for the disk-like extended atmospheres of Be stars. Details of a polarimeter for the measurement of the linear polarization of astronomical point sources are also presented with narrow band (Δ lambda = 100A) measurements of the polarization of γ Cas from lambda 4000 to lambda 5800

Ionic polarization

International Nuclear Information System (INIS)

Mahan, G.D.

1992-01-01

Ferroelectricity occurs in many different kinds of materials. Many of the technologically important solids, which are ferroelectric, can be classified as ionic. Any microscopic theory of ferroelectricity must contain a description of local polarization forces. We have collaborated in the development of a theory of ionic polarization which is quite successful. Its basic assumption is that the polarization is derived from the properties of the individual ions. We have applied this theory successfully to diverse subjects as linear and nonlinear optical response, phonon dispersion, and piezoelectricity. We have developed numerical methods using the local Density approximation to calculate the multipole polarizabilities of ions when subject to various fields. We have also developed methods of calculating the nonlinear hyperpolarizability, and showed that it can be used to explain light scattering experiments. This paper elaborates on this polarization theory

POLARIZED BEAMS: 1 - Longitudinal electron spin polarization at HERA

Energy Technology Data Exchange (ETDEWEB)

Anon.

1994-09-15

Wednesday 4 May marked a turning point in the art of the manipulation of spins in electron storage rings: longitudinal electron spin polarization (with the spins oriented along the electrons' direction of motion) was established in the electron ring of HERA, the electronproton collider at DESY in Hamburg. A polarization level of about 55% was obtained and polarizations of over 60% were reproducibly obtained in the following days. The beam energy was 27.52 GeV, corresponding to half integer spin tune of 62.5.

Polarized Electrons at Jefferson Laboratory

Energy Technology Data Exchange (ETDEWEB)

Sinclair, C.K.

1997-12-31

The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously.initial operational experience with the polarized source will be presented.

Adapting the HSV polarization-color mapping for regions with low irradiance and high polarization.

Science.gov (United States)

Scott Tyo, J; Ratliff, Bradley M; Alenin, Andrey S

2016-10-15

Many mappings from polarization into color have been developed so that polarization information can be displayed. One of the most common of these maps the angle of linear polarization into color hue and degree of linear polarization into color saturation, while preserving the irradiance information from the polarization data. While this strategy enjoys wide popularity, there is a large class of polarization images for which it is not ideal. It is common to have images where the strongest polarization signatures (in terms of degree of polarization) occur in regions of relatively low irradiance: either in shadow in reflective bands or in cold regions in emissive bands. Since the irradiance is low, the chromatic properties of the resulting images are generally not apparent. Here we present an alternate mapping that uses the statistics of the angle of polarization as a measure of confidence in the polarization signature, then amplifies the irradiance in regions of high confidence, and leaves it unchanged in regions of low confidence. Results are shown from an LWIR and a visible spectrum imager.

Polarized Moessbauer transitions

International Nuclear Information System (INIS)

Barb, D.

1975-01-01

Theoretical aspects of the emission, absorption and scattering of polarized gamma rays are reviewed for a general case of combined magnetic and electric hyperfine interactions; various possibilities of obtaining polarized gamma sources are described and examples are given of the applications of Moessbauer spectroscopy with polarized gamma rays in solving problems of solid state physics. (A.K.)

Polarization division multiple access with polarization modulation for LOS wireless communications

Directory of Open Access Journals (Sweden)

Cao Bin

2011-01-01

Full Text Available Abstract In this paper, we discuss a potential multiple access and modulation scheme based on polarized states (PS of electromagnetic (EM waves for line-of-sight (LOS communications. The proposed scheme is theoretic different from the existing polar modulation for EDGE and WCDMA systems. We propose the detailed bit representation (modulation and multiple access scheme using PS. Because of the inflexibility of polarization information in the time and frequency domains, as well as independence of frequency and space, the polarization information can be used independently for wireless communications, i.e., another independent resource domain that can be utilized. Due to the independence between the PS and the specific features of signals (such as waveform, bandwidth and data rate, the discussed polarization division multiple access (PDMA and polarization modulation (PM are expected to improve the spectrum utilization effectively. It is proved that the polarization filtering technique can be adopted in the PDMA-PM wireless communications to separate the multiuser signals and demodulate the bit information representing by PS for desired user. Some theoretical analysis is done to demonstrate the feasibility of the proposed scheme, and the simulation results are made to evaluate the performance of the suggested system.

Polarization at SLC

International Nuclear Information System (INIS)

Swartz, M.L.

1988-07-01

The SLAC Linear Collider has been designed to readily accommodate polarized electron beams. Considerable effort has been made to implement a polarized source, a spin rotation system, and a system to monitor the beam polarization. Nearly all major components have been fabricated. At the current time, several source and polarimeter components have been installed. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. It is expected that a beam polarization of 45% will be achieved with no loss in luminosity. 13 refs., 15 figs

Polarized electrons at Jefferson laboratory

International Nuclear Information System (INIS)

Sinclair, C.K.

1998-01-01

The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously. Initial operational experience with the polarized source will be presented. copyright 1998 American Institute of Physics

When the swimming gets tough, the tough form a biofilm.

Science.gov (United States)

Belas, Robert

2013-10-01

Bacteria live either as independent planktonic cells or as members of surface-attached communities called biofilms. Motility and biofilm development are mutually exclusive events, and control of the phase of this 'swim-or-stick' switch involves the ability of the bacterium to sense and respond appropriately to a surface. Cairns et al. (2013) report that the Bacillus subtilis flagellum functions in surface-sensing. Using mutants of B. subtilis that prevent flagellum rotation, they measured the expression and activity of DegU, the response regulator of the two-component DegS-DegU circuit. DegU activity and degU transcription increased when flagellum rotation was prevented, and were dependent on the DegS kinase. Inhibiting flagellar rotation by overexpressing the EpsE flagellar 'clutch' or addition of anti-flagellin antiserum also increased degU transcription and activity. These results suggest B. subtilis senses restriction of flagellum rotation as the cell nears a surface. Inhibition of the flagellum activates the DegS-DegU circuit to turn on biofilm formation, i.e. the flagellum is acting as a mechanosensor of surfaces. B. subtilis joins an ever-expanding group of bacteria, including species of Vibrio, Proteus and Caulobacter that use the flagellum as a surface sensor. © 2013 John Wiley & Sons Ltd.

Suomi National Polar-Orbiting Partnership Visible Infrared Imaging Radiometer Suite Polarization Sensitivity Analysis

Science.gov (United States)

Sun, Junqiang; Xiong, Xiaoxiong; Waluschka, Eugene; Wang, Menghua

2016-01-01

The Visible Infrared Imaging Radiometer Suite (VIIRS) is one of five instruments onboard the Suomi National Polar-Orbiting Partnership (SNPP) satellite that launched from Vandenberg Air Force Base, California, on October 28, 2011. It is a whiskbroom radiometer that provides +/-56.28deg scans of the Earth view. It has 22 bands, among which 14 are reflective solar bands (RSBs). The RSBs cover a wavelength range from 410 to 2250 nm. The RSBs of a remote sensor are usually sensitive to the polarization of incident light. For VIIRS, it is specified that the polarization factor should be smaller than 3% for 410 and 862 nm bands and 2.5% for other RSBs for the scan angle within +/-45deg. Several polarization sensitivity tests were performed prelaunch for SNPP VIIRS. The first few tests either had large uncertainty or were less reliable, while the last one was believed to provide the more accurate information about the polarization property of the instrument. In this paper, the measured data in the last polarization sensitivity test are analyzed, and the polarization factors and phase angles are derived from the measurements for all the RSBs. The derived polarization factors and phase angles are band, detector, and scan angle dependent. For near-infrared bands, they also depend on the half-angle mirror side. Nevertheless, the derived polarization factors are all within the specification, although the strong detector dependence of the polarization parameters was not expected. Compared to the Moderate Resolution Imaging Spectroradiometer on both Aqua and Terra satellites, the polarization effect on VIIRS RSB is much smaller.

A Si nanocube array polarizer

Science.gov (United States)

Chen, Linghua; Jiang, Yingjie; Xing, Li; Yao, Jun

2017-10-01

We have proposed a full dielectric (silicon) nanocube array polarizer based on a silicon dioxide substrate. Each polarization unit column includes a plurality of equal spaced polarization units. By optimizing the length, the width, the height of the polarization units and the center distance of adjacent polarization unit (x direction and y direction), an extinction ratio (ER) of higher than 25dB was obtained theoretically when the incident light wavelength is 1550nm. while for applications of most polarization optical elements, ER above 10dB is enough. With this condition, the polarizer we designed can work in a wide wavelength range from 1509.31nm to 1611.51nm. Compared with the previous polarizer, we have introduced a polarizer which is a full dielectric device, which solves the problems of low efficiency caused by Ohmic loss and weak coupling. Furthermore, compared with the existing optical polarizers, our polarizer has the advantages of thin thickness, small size, light weight, and low processing difficulty, which is in line with the future development trend of optical elements.

Polarization: A Must for Fusion

Directory of Open Access Journals (Sweden)

Guidal M.

2012-10-01

Full Text Available Recent realistic simulations confirm that the polarization of the fuel would improve significantly the DT fusion efficiency. We have proposed an experiment to test the persistence of the polarization in a fusion process, using a terawatt laser hitting a polarized HD target. The polarized deuterons heated in the plasma induced by the laser can fuse producing a 3He and a neutron in the final state. The angular distribution of the neutrons and the change in the corresponding total cross section are related to the polarization persistence. The experimental polarization of DT fuel is a technological challenge. Possible paths for Magnetic Confinement Fusion (MCF and for Inertial Confinement Fusion (ICF are reviewed. For MCF, polarized gas can be used. For ICF, cryogenic targets are required. We consider both, the polarization of gas and the polarization of solid DT, emphasizing the Dynamic Nuclear polarization (DNP of HD and DT molecules.

PolarTREC—A Model Program for Taking Polar Literacy into the Future

Science.gov (United States)

Warburton, J.; Timm, K.; Larson, A. M.

2009-12-01

Polar TREC—Teachers and Researchers Exploring and Collaborating, is a three-year (2007-2009) NSF-funded International Polar Year (IPY) teacher professional development program that advances Science, Technology, Engineering, and Mathematics (STEM) education by improving teacher content knowledge and instructional practices through Teacher Research Experiences (TRE) in the Arctic and Antarctic. Leveraging profound changes and fascinating science taking place in the polar regions, PolarTREC broadly disseminates activities and products to students, educators, researchers, and the public, connecting them with the Arctic and Antarctica and sustaining the widespread interest in the polar regions and building on the enthusiasm that was generated through IPY. Central to the PolarTREC Teacher Research Experience Model, over 40 teachers have spent two to eight weeks participating in hands-on research in the polar regions and sharing their experiences with diverse audiences via live events, online multimedia journals, and interactive bulletin boards. The Connecting Arctic/Antarctic Researchers and Educators (CARE) Network unifies learning community members participants, alumni, and others, developing a sustainable association of education professionals networking to share and apply polar STEM content and pedagogical skills. Educator and student feedback from preliminary results of the program evaluation has shown that PolarTREC’s comprehensive program activities have many positive impacts on educators and their ability to teach science concepts and improve their teaching methods. Additionally, K-12 students polled in interest surveys showed significant changes in key areas including amount of time spent in school exploring research activities, importance of understanding science for future work, importance of understanding the polar regions as a person in today’s world, as well as increased self-reported knowledge and interest in numerous science content areas. Building

Generating highly polarized nuclear spins in solution using dynamic nuclear polarization

DEFF Research Database (Denmark)

Wolber, J.; Ellner, F.; Fridlund, B.

2004-01-01

A method to generate strongly polarized nuclear spins in solution has been developed, using Dynamic Nuclear Polarization (DNP) at a temperature of 1.2K, and at a field of 3.354T, corresponding to an electron spin resonance frequency of 94GHz. Trityl radicals are used to directly polarize 13C...... and other low-γ nuclei. Subsequent to the DNP process, the solid sample is dissolved rapidly with a warm solvent to create a solution of molecules with highly polarized nuclear spins. Two main applications are proposed: high-resolution liquid state NMR with enhanced sensitivity, and the use...

Polarized Light Microscopy

Science.gov (United States)

Frandsen, Athela F.

2016-01-01

Polarized light microscopy (PLM) is a technique which employs the use of polarizing filters to obtain substantial optical property information about the material which is being observed. This information can be combined with other microscopy techniques to confirm or elucidate the identity of an unknown material, determine whether a particular contaminant is present (as with asbestos analysis), or to provide important information that can be used to refine a manufacturing or chemical process. PLM was the major microscopy technique in use for identification of materials for nearly a century since its introduction in 1834 by William Fox Talbot, as other techniques such as SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared spectroscopy), XPD (X-ray Powder Diffraction), and TEM (Transmission Electron Microscopy) had not yet been developed. Today, it is still the only technique approved by the Environmental Protection Agency (EPA) for asbestos analysis, and is often the technique first applied for identification of unknown materials. PLM uses different configurations in order to determine different material properties. With each configuration additional clues can be gathered, leading to a conclusion of material identity. With no polarizing filter, the microscope can be used just as a stereo optical microscope, and view qualities such as morphology, size, and number of phases. With a single polarizing filter (single polars), additional properties can be established, such as pleochroism, individual refractive indices, and dispersion staining. With two polarizing filters (crossed polars), even more can be deduced: isotropy vs. anisotropy, extinction angle, birefringence/degree of birefringence, sign of elongation, and anomalous polarization colors, among others. With the use of PLM many of these properties can be determined in a matter of seconds, even for those who are not highly trained. McCrone, a leader in the field of polarized light microscopy, often

Non-polar InGaN quantum dot emission with crystal-axis oriented linear polarization

Energy Technology Data Exchange (ETDEWEB)

Reid, Benjamin P. L., E-mail: benjamin.reid@physics.ox.ac.uk; Chan, Christopher C. S.; Taylor, Robert A. [Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom); Kocher, Claudius [Department of Physics, University of Konstanz, Konstanz 78457 (Germany); Zhu, Tongtong; Oehler, Fabrice; Oliver, Rachel A. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

2015-04-27

Polarization sensitive photoluminescence is performed on single non-polar InGaN quantum dots. The studied InGaN quantum dots are found to have linearly polarized emission with a common polarization direction defined by the [0001] crystal axis. Around half of ∼40 studied dots have a polarization degree of 1. For those lines with a polarization degree less than 1, we can resolve fine structure splittings between −800 μeV and +800 μeV, with no clear correlation between fine structure splitting and emission energy.

The Physics of Polarization

Science.gov (United States)

Landi Degl'Innocenti, Egidio

2015-10-01

The introductory lecture that has been delivered at this Symposium is a condensed version of an extended course held by the author at the XII Canary Island Winter School from November 13 to November 21, 2000. The full series of lectures can be found in Landi Degl'Innocenti (2002). The original reference is organized in 20 Sections that are here itemized: 1. Introduction, 2. Description of polarized radiation, 3. Polarization and optical devices: Jones calculus and Muller matrices, 4. The Fresnel equations, 5. Dichroism and anomalous dispersion, 6. Polarization in everyday life, 7. Polarization due to radiating charges, 8. The linear antenna, 9. Thomson scattering, 10. Rayleigh scattering, 11. A digression on Mie scattering, 12. Bremsstrahlung radiation, 13. Cyclotron radiation, 14. Synchrotron radiation, 15. Polarization in spectral lines, 16. Density matrix and atomic polarization, 17. Radiative transfer and statistical equilibrium equations, 18. The amplification condition in polarized radiative transfer, and 19. Coupling radiative transfer and statistical equilibrium equations.

Fiber-Based Polarization Diversity Detection for Polarization-Sensitive Optical Coherence Tomography

Directory of Open Access Journals (Sweden)

Hamid Pahlevaninezhad

2014-09-01

Full Text Available We present a new fiber-based polarization diversity detection (PDD scheme for polarization sensitive optical coherence tomography (PSOCT. This implementation uses a new custom miniaturized polarization-maintaining fiber coupler with single mode (SM fiber inputs and polarization maintaining (PM fiber outputs. The SM fiber inputs obviate matching the optical lengths of the two orthogonal OCT polarization channels prior to interference while the PM fiber outputs ensure defined orthogonal axes after interference. Advantages of this detection scheme over those with bulk optics PDD include lower cost, easier miniaturization, and more relaxed alignment and handling issues. We incorporate this PDD scheme into a galvanometer-scanned OCT system to demonstrate system calibration and PSOCT imaging of an achromatic quarter-wave plate, fingernail in vivo, and chicken breast, salmon, cow leg, and basa fish muscle samples ex vivo.

Bringing Society to a Changing Polar Ocean: Polar Interdisciplinary Coordinated Education (ICE)

Science.gov (United States)

Schofield, O.

2015-12-01

Environmental changes in the Arctic and Antarctic appear to be accelerating and scientists are trying to understand both the patterns and the impacts of change. These changes will have profound impact on humanity and create a need for public education about these critical habitats. We have focused on a two-pronged strategy to increase public awareness as well as enable educators to discuss comfortably the implications of climate change. Our first focus is on entraining public support through the development of science documentaries about the science and people who conduct it. Antarctic Edge is a feature length award-winning documentary about climate change that has been released in May 2015 and has garnered interest in movie theatres and on social media stores (NetFlix, ITunes). This broad outreach is coupled with our group's interest assisting educators formally. The majority of current polar education is focused on direct educator engagement through personal research experiences that have impact on the participating educators' classrooms. Polar Interdisciplinary Coordinated Education (ICE) proposes to improve educator and student engagement in polar sciences through exposure to scientists and polar data. Through professional development and the creation of data tools, Polar ICE will reduce the logistical costs of bringing polar science to students in grades 6-16. We will provide opportunities to: 1) build capacity of polar scientists in communicating and engaging with diverse audiences; 2) create scalable, in-person and virtual opportunities for educators and students to engage with polar scientists and their research through data visualizations, data activities, educator workshops, webinars, and student research symposia; and 3) evaluate the outcomes of Polar ICE and contribute to our understanding of science education practices. We will use a blended learning approach to promote partnerships and cross-disciplinary sharing. This combined multi-pronged approach

Techniques in polarization physics

International Nuclear Information System (INIS)

Clausnitzer, G.

1974-01-01

A review of the current status of the technical tools necessary to perform different kinds of polarization experiments is presented, and the absolute and relative accuracy with which data can be obtained is discussed. A description of polarized targets and sources of polarized fast neutrons is included. Applications of polarization techniques to other fields is mentioned briefly. (14 figures, 3 tables, 110 references) (U.S.)

Polarization: A must for fusion

Directory of Open Access Journals (Sweden)

Didelez J.-P.

2013-11-01

Full Text Available The complete polarization of DT fuel would increase the fusion reactivity by 50% in magnetic as well as in inertial confinements. The persistence of polarization in a fusion process could be tested, using a terawatt laser hitting a polarized HD target. The polarized deuterons heated in the plasma induced by the laser can fuse producing a 3He and a neutron in the final state. The angular distribution of the emitted neutrons and the change in the corresponding total Cross Section (CS can sign the polarization persistence. The polarization of solid H2, D2 or T2 Hydrogen isotopes is very difficult. However, it has been possible to polarize HD, a hetero-molecular form of Hydrogen, by static polarization, at very low temperature and very high field. The radioactivity of DT molecules forbids there high polarization by the static method, therefore one has to develop the Dynamic Nuclear Polarization (DNP by RF transitions. The DNP of HD has been investigated in the past. The magnetic properties of HD and DT molecules are very similar, it is therefore expected that any polarization result obtained with HD could be extrapolated to DT.

An elliptically-polarizing undulator with phase adjustable energy and polarization

International Nuclear Information System (INIS)

Lidia, S.

1993-08-01

The authors present a planar helical undulator designed to produce elliptically polarized light. Helical magnetic fields may be produced by a variety of undulators with four parallel cassettes of magnets. In their design, all cassettes are mounted in two planes on slides so that they may be moved parallel to the electron beam. This allows the undulator to produce x-rays of left- or right-handed elliptical or circular polarization as well as horizontal or vertical linear polarization. In model calculations, they have found that by sliding the top pair of rows with respect to the bottom pair, or the left pair with respect to the right pair, they retain the polarization setting but change the magnetic field strength, and hence the x-ray energy. This allows them to select both energy and polarization by independent phase adjustments alone, without changing the gap between the rows. Such a design may be simpler to construct than an adjustable gap machine. The authors present calculations that model its operation and its effects on an electron beam

Linearly polarized photons at ELSA

Energy Technology Data Exchange (ETDEWEB)

Eberhardt, Holger [Physikalisches Institut, Universitaet Bonn (Germany)

2009-07-01

To investigate the nucleon resonance regime in meson photoproduction, double polarization experiments are currently performed at the electron accelerator ELSA in Bonn. The experiments make use of a polarized target and circularly or linearly polarized photon beams. Linearly polarized photons are produced by coherent bremsstrahlung from an accurately aligned diamond crystal. The orientation of the crystal with respect to the electron beam is measured using the Stonehenge-Technique. Both, the energy of maximum polarization and the plane of polarization, can be deliberately chosen for the experiment. The linearly polarized beam provides the basis for the measurement of azimuthal beam asymmetries, such as {sigma} (unpolarized target) and G (polarized target). These observables are extracted in various single and multiple meson photoproduction channels.

Polarized atomic beams for targets

International Nuclear Information System (INIS)

Grueebler, W.

1984-01-01

The basic principle of the production of polarized atomic hydrogen and deuterium beams are reviewed. The status of the present available polarization, density and intensity are presented. The improvement of atomic beam density by cooling the hydrogen atoms to low velocity is discussed. The possible use of polarized atomic beams as targets in storage rings is shown. It is proposed that polarized atomic beams can be used to produce polarized gas targets with high polarization and greatly improved density

Polarized Proton Collisions at RHIC

CERN Document Server

Bai, Mei; Alekseev, Igor G; Alessi, James; Beebe-Wang, Joanne; Blaskiewicz, Michael; Bravar, Alessandro; Brennan, Joseph M; Bruno, Donald; Bunce, Gerry; Butler, John J; Cameron, Peter; Connolly, Roger; De Long, Joseph; Drees, Angelika; Fischer, Wolfram; Ganetis, George; Gardner, Chris J; Glenn, Joseph; Hayes, Thomas; Hseuh Hsiao Chaun; Huang, Haixin; Ingrassia, Peter; Iriso, Ubaldo; Laster, Jonathan S; Lee, Roger C; Luccio, Alfredo U; Luo, Yun; MacKay, William W; Makdisi, Yousef; Marr, Gregory J; Marusic, Al; McIntyre, Gary; Michnoff, Robert; Montag, Christoph; Morris, John; Nicoletti, Tony; Oddo, Peter; Oerter, Brian; Osamu, Jinnouchi; Pilat, Fulvia Caterina; Ptitsyn, Vadim; Roser, Thomas; Satogata, Todd; Smith, Kevin T; Svirida, Dima; Tepikian, Steven; Tomas, Rogelio; Trbojevic, Dejan; Tsoupas, Nicholaos; Tuozzolo, Joseph; Vetter, Kurt; Wilinski, Michelle; Zaltsman, Alex; Zelenski, Anatoli; Zeno, Keith; Zhang, S Y

2005-01-01

The Relativistic Heavy Ion Collider~(RHIC) provides not only collisions of ions but also collisions of polarized protons. In a circular accelerator, the polarization of polarized proton beam can be partially or fully lost when a spin depolarizing resonance is encountered. To preserve the beam polarization during acceleration, two full Siberian snakes were employed in RHIC to avoid depolarizing resonances. In 2003, polarized proton beams were accelerated to 100~GeV and collided in RHIC. Beams were brought into collisions with longitudinal polarization at the experiments STAR and PHENIX by using spin rotators. RHIC polarized proton run experience demonstrates that optimizing polarization transmission efficiency and improving luminosity performance are significant challenges. Currently, the luminosity lifetime in RHIC is limited by the beam-beam effect. The current state of RHIC polarized proton program, including its dedicated physics run in 2005 and efforts to optimize luminosity production in beam-beam limite...

Polarization recovery through scattering media.

Science.gov (United States)

de Aguiar, Hilton B; Gigan, Sylvain; Brasselet, Sophie

2017-09-01

The control and use of light polarization in optical sciences and engineering are widespread. Despite remarkable developments in polarization-resolved imaging for life sciences, their transposition to strongly scattering media is currently not possible, because of the inherent depolarization effects arising from multiple scattering. We show an unprecedented phenomenon that opens new possibilities for polarization-resolved microscopy in strongly scattering media: polarization recovery via broadband wavefront shaping. We demonstrate focusing and recovery of the original injected polarization state without using any polarizing optics at the detection. To enable molecular-level structural imaging, an arbitrary rotation of the input polarization does not degrade the quality of the focus. We further exploit the robustness of polarization recovery for structural imaging of biological tissues through scattering media. We retrieve molecular-level organization information of collagen fibers by polarization-resolved second harmonic generation, a topic of wide interest for diagnosis in biomedical optics. Ultimately, the observation of this new phenomenon paves the way for extending current polarization-based methods to strongly scattering environments.

On feasibility of the experiments with a polarized deuteron beam and a polarized target at Charles University in relation with polarized fusion

International Nuclear Information System (INIS)

Plis, Yu.A.

2001-01-01

There is an interest in the problem of polarized fusion with the neutron-free d 3 He reaction. Up to now, the experimental data on the cross sections of two dd reactions, which produce neutrons at once or through secondary dt reaction, are absent for polarized deuterons. There is a relatively cheap way to carry out the experiments with polarized deuterons at the Charles University in Prague. A polarized deuteron beam with energy from 100 keV up to approximately 1 MeV may be produced on the Van de Graaff accelerator by the channeling of a deuteron beam through magnetized Ni single crystal foil, according M. Kaminsky [Phys. Rev. Lett. 23, 819 (1969)]. This method permits to produce a polarized deuteron beam of an energy ≤1 MeV with a current of ∼1 nA, vector polarization P 3 up to 2/3 and tensor polarization P 33 =0. It will be necessary to modify the existing polarized target at Charles University for work with a low energy deuteron beam [N. S. Borisov et al., Nucl. Instr. and Meth. A 345, 421 (1994)

Polarized particles in storage rings

International Nuclear Information System (INIS)

Derbenev, Ya.S.; Kondratenko, A.M.; Serednyakov, S.I.; Skrinskij, A.N.; Tumajkin, G.M.; Shatunov, Yu.M.

1977-01-01

Experiments with polarized beams on the VEPP-2M and SPEAK storage rings are described. Possible methods of producing polarized particle beams in storage rings as well as method of polarization monitoring are counted. Considered are the processes of radiation polarization of electrons and positrons. It is shown, that to preserve radiation polarization the introduction of regions with a strong sign-variable magnetic field is recommended. Methods of polarization measurement are counted. It is suggested for high energies to use dependence of synchrotron radiation power on transverse polarization of electrons and positrons. Examples of using polarizability of colliding beams in storage rings are presented

Polarized neutron capture in polarized 59Co and 165Ho nuclei

International Nuclear Information System (INIS)

Bosman, J.J.

1976-01-01

Gamma spectroscopy on the reactions 59 Co(n,γ) 60 Co and 165 Ho(n,γ) 166 Ho with polarized neutrons and polarized targets enabled the assignment of spins to 36 levels in 60 Co and 15 levels in 166 Ho. Several of them had not been reported earlier. The techniques used to polarize neutron beams and targets and the gamma-spectroscopy are extensively discussed

Review of polarized ammonium target

International Nuclear Information System (INIS)

Matsuda, Tatsuo

1987-01-01

Recently, ammonia (NH 3 ) and deutron ammonia (ND 3 ), instead of conventional alcohol substances, have been used more frequently as a polarized target substance for experiments of polarization at high energy regions. This article reviews major features of the polarized (deutron) ammonia targets. The dynamic nuclear polarization (DNT) method is widely used in high energy polarization experiments. While only a low polarization degree of hydrogen nucleus of 1.7 percent can be obtained by the Brute force method, DNP can produce polarization as high as ∼ 90 percent (2.5 T, ∼ 200 mK). In 1979, ammonia was irradiated with radiations to form NH 2 free radicals, resulting in the achievement of a high polarization degree of greater than 90 percent (hydrogen). Since then, ammonia and deutron ammonia have increasingly been replacing alcohols including butanol. Irradiation of a target substance with radiations destroys the structure of the substance, leading to a decrease in polarization degree. However, ammonia produces unpaired electrons as a result of irradiation, allowing it to be highly resistant to radiation. This report also present some study results, including observations on effects of radiation on the polarization degree of a target, effects of annealing, and polarization of 14 N. A process for producing an ammonia target is also described. (Nogami, K.)

Achievement of transportable polarized D, in solid HD, with a one day passively maintained polarization

International Nuclear Information System (INIS)

Honig, A.; Alexander, N.; Fan, Q.; Wei, X.; Yu, Y.Y.

1993-01-01

At a previous workshop, we discussed evaporating solid HD with spin-polarized deuterons to produce a high density polarized deuteron gaseous internal target. Since then, we have achieved in solid HD 38% polarized D, whose spin-lattice relaxation time at 1.5 K in a field of 0.1 T is of the order of a day. Optimization of the procedure with the present apparatus should result in 60% D polarization, and longer polarization holding times. The polarized sample of approximately 0.2 cm 3 volume used here is extractable from the dilution refrigerator with a cold-transfer apparatus which maintains the sample at or below 5 K, insuring retention of the high polarization. It is subsequently insertable into a variety of systems, and employable as a polarized solid, liquid, or gas. We are exploring the possibility of extending the polarization maintenance time to about a month (with a matched 1 month preparation time), of polarizing metastably H as well as D, and of producing much larger samples, of the order of 100 cm 3

Acceleration of polarized particles

International Nuclear Information System (INIS)

Buon, J.

1992-05-01

The spin kinetics of polarized beams in circular accelerators is reviewed in the case of spin-1/2 particles (electrons and protons) with emphasis on the depolarization phenomena. The acceleration of polarized proton beams in synchrotrons is described together with the cures applied to reduce depolarization, including the use of 'Siberian Snakes'. The in-situ polarization of electrons in storage rings due to synchrotron radiation is studied as well as depolarization in presence of ring imperfections. The applications of electron polarization to accurately calibrate the rings in energy and to use polarized beams in colliding-beam experiments are reviewed. (author) 76 refs., 19 figs., 1 tab

Role of calmodulin and calcineurin in regulating flagellar motility and wave polarity in Leishmania.

Science.gov (United States)

Mukhopadhyay, Aakash Gautam; Dey, Chinmoy Sankar

2017-11-01

We have previously reported the involvement of cyclic AMP in regulating flagellar waveforms in Leishmania. Here, we investigated the roles of calcium, calmodulin, and calcineurin in flagellar motility regulation in L. donovani. Using high-speed videomicroscopy, we show that calcium-independent calmodulin and calcineurin activity is necessary for motility in Leishmania. Inhibition of calmodulin and calcineurin induced ciliary beats interrupting flagellar beating in both live (in vivo) and ATP-reactivated (in vitro) parasites. Our results indicate that signaling mediated by calmodulin and calcineurin operates antagonistically to cAMP signaling in regulating the waveforms of Leishmania flagellum. These two pathways are possibly involved in maintaining the balance between the two waveforms, essential for responding to environmental cues, survival, and infectivity.

Determination of the polarization states of an arbitrary polarized terahertz beam: vectorial vortex analysis.

Science.gov (United States)

Wakayama, Toshitaka; Higashiguchi, Takeshi; Oikawa, Hiroki; Sakaue, Kazuyuki; Washio, Masakazu; Yonemura, Motoki; Yoshizawa, Toru; Tyo, J Scott; Otani, Yukitoshi

2015-03-24

Vectorial vortex analysis is used to determine the polarization states of an arbitrarily polarized terahertz (0.1-1.6 THz) beam using THz achromatic axially symmetric wave (TAS) plates, which have a phase retardance of Δ = 163° and are made of polytetrafluorethylene. Polarized THz beams are converted into THz vectorial vortex beams with no spatial or wavelength dispersion, and the unknown polarization states of the incident THz beams are reconstructed. The polarization determination is also demonstrated at frequencies of 0.16 and 0.36 THz. The results obtained by solving the inverse source problem agree with the values used in the experiments. This vectorial vortex analysis enables a determination of the polarization states of the incident THz beam from the THz image. The polarization states of the beams are estimated after they pass through the TAS plates. The results validate this new approach to polarization detection for intense THz sources. It could find application in such cutting edge areas of physics as nonlinear THz photonics and plasmon excitation, because TAS plates not only instantaneously elucidate the polarization of an enclosed THz beam but can also passively control THz vectorial vortex beams.

The use of transpositional mutagenesis to study bacterial virulence

International Nuclear Information System (INIS)

Mousa, M.A.B.

1989-01-01

Extracellular protease of A. hydrophila was shown to be lethal factor for fish. Protease deficient mutants were obtained from A. hydrophila strain 79. A. hydrophila was mutagenized by inserting Tn10 (tetracycline resistance factor) into the chromosome. This was achieved by conjugation between A. hydrophila and E. coli which contains Tn10 carried on the suicide vector pRK2013. Virulence of the protease deficient mutants was determined by injecting into channel catfish and comparing the mortalities produced by the mutants to that produced by the wild type strain. Protease deficient isolates were non virulent when inoculated into channel catfish (compared to the wild type strain). Proteolytic activities of some protease deficient isolates were compared to the activities of the wild type strain using a quantitative plate technique. The following substrates were used to study the proteolytic activities: casein, gelatin, elastin, staphylococcus and klebsiella. Loss of the proteolytic activity of caseinase, gelatinase and elastase was associated with the loss of virulence of A. hydrophila. Acquiring the DNA from the media was studied using a new transformation technique; no artificial competence was provided. A strain of Escherchi coli, Edwardsiella ictaluri, and Aeromonas hydrophila acquired antibiotic resistance markers when they were grown on media containing the target antibiotic and the resistance markers. When homologous and heterologous 32 P-labelled DNA were supplied to growing cultures of A. hydrophila, A. hydrophila cells and their chromosomes were found labelled. Total cellular radioactivity of the culture receiving heterologous labelled DNA was higher than the culture receiving homologous DNA; however the chromosomal radioactivity was on the opposite where it was higher in case of the culture receiving homologous DNA

Polarized light and optical measurement

CERN Document Server

Clarke, D N; Ter Haar, D

2013-01-01

Polarized Light and Optical Measurement is a five-chapter book that begins with a self-consistent conceptual picture of the phenomenon of polarization. Chapter 2 describes a number of interactions of light and matter used in devising optical elements in polarization studies. Specific optical elements are given in Chapter 3. The last two chapters explore the measurement of the state of polarization and the various roles played in optical instrumentation by polarization and polarization-sensitive elements. This book will provide useful information in this field of interest for research workers,

Towards helium-3 neutron polarizers

International Nuclear Information System (INIS)

Tasset, F.

1995-01-01

With a large absorption cross-section entirely due to antiparallel spin capture, polarized helium-3 is presently the most promising broad-band polarizer for thermal and epithermal neutrons. Immediate interest was raised amongst the neutron community when a dense gaseous 3 He polarizer was used for the first time in 1988, on a pulsed neutron beam at Los Alamos. With 20 W of laser power on a 30 cm long, 8.6 atm target, 40% 3 He polarization was achieved in a recent polarized electron scattering experiment at SLAC. In this technique the 3 He nuclei are polarized directly at an appropriate high pressure through spin-exchange collisions with a thick, optically pumped rubidium vapor. A different and competitive approach is being presently developed at Mainz University in collaboration with ENS Paris and now the ILL. A discharge is established in pure 3 He at low pressure producing excited metastable atoms which can be optically pumped with infra-red light. Highly effective exchange collision with the atoms remaining in the ground state quickly produces 75% polarization at 1.5 mbar. A truly non-magnetic system then compresses the polarized gas up to several bars as required. The most recent machine comprises a two-stage glass-titanium compressor. In less than 1 h it can inflate a 100 cm 3 target cell with three bars of polarized gas. The very long relaxation times (several days) now being obtained at high pressure with a special metallic coating on the glass walls, the polarized cell can be detached and inserted in the neutron beam as polarizer. We expect 50% 3 He-polarization to be reached soon, allowing such filters to compete favorably with existing Heusler-crystal polarizers at thermal and short neutron wavelengths. It must be stressed that such a system based on a 3 He polarization factory able to feed several passive, transportable, polarizers is well matched to neutron scattering needs. (orig.)

Multifocal Aeromonas Osteomyelitis in a Child with Leukemia

Directory of Open Access Journals (Sweden)

Dimitrios Doganis

2016-01-01

Full Text Available Aeromonas hydrophila is a Gram negative organism causing both intestinal and extraintestinal disease. The case of a 14-year-old girl with underlying immunodeficiency and leukemia who developed systemic A. hydrophila infection is described in this report. While in deep bone marrow aplasia she developed fever, severe pain in the lower extremities, and swelling of the left femur. Blood culture showed Escherichia coli and A. hydrophila whereas pus culture from the soft tissue swelling showed the presence of A. hydrophila. Imaging studies showed diffuse osteolytic lesions. Patient received 5 months of intravenous and oral antibiotics and she improved clinically whereas the radiology findings persisted.

Design of reproducible polarized and non-polarized edge filters using genetic algorithm

International Nuclear Information System (INIS)

Ejigu, Efrem Kebede; Lacquet, B M

2010-01-01

Recent advancement in optical fibre communications technology is partly due to the advancement of optical thin film technology. The advancement of optical thin film technology includes the development of new and existing optical filter design methods. The genetic algorithm is one of the new design methods that show promising results in designing a number of complicated design specifications. It is the finding of this study that the genetic algorithm design method, through its optimization capability, can give more reliable and reproducible designs of any specifications. The design method in this study optimizes the thickness of each layer to get to the best possible solution. Its capability and unavoidable limitations in designing polarized and non-polarized edge filters from absorptive and dispersive materials is well demonstrated. It is also demonstrated that polarized and non-polarized designs from the genetic algorithm are reproducible with great success. This research has accomplished the great task of formulating a computer program using the genetic algorithm in a Matlab environment for the design of a reproducible polarized and non-polarized filters of any sort from any kind of materials

Polarized target as analyzer of polarization of particle beam with spin Ssub(B)=1/2

International Nuclear Information System (INIS)

Golovin, V.M.; Golubeva, M.B.; Gornushkin, Yu.A.

1982-01-01

A possibility of using a polarized target as a target analyzer of beam particle polarization (Ssub(T)=1/2 Psub(T) vector) so that all the components of beam polarization Ssub(B)=1/2 anti Psub(B) should be determined in one experiment, is revealed. A proton polarization target is considered as a polarization target-analyzer. Asub(SK) and Asub(kk) asymmetry tensors are considered for elastic pp and pn scatterings by amplitudes of NN scattering which attain the values of 0.3-0.9 at 95-400 MeV. Asub(kk)(pp) and Asub(sk)(pp) are experimentally measured in the 445-576 MeV range. It is found that their highest absolute values are equal to 0.4-0.5 and 0.2-0.3 respectively. Elastic proton scattering on polarized electrons may be another variant of using polarized target for measuring proton beam polarization. Asub(sk) and Asub(kk) components of asymmetry tensor of elastic pe scattering are graphically presented. A possibility of using a polarized charge with spin I=1/2 as a target-analyzer of particle beam polarization is marked

Calculation of polarization effects

International Nuclear Information System (INIS)

Chao, A.W.

1983-09-01

Basically there are two areas of accelerator applications that involve beam polarization. One is the acceleration of a polarized beam (most likely a proton beam) in a synchrotron. Another concerns polarized beams in an electron storage ring. In both areas, numerical techniques have been very useful

Preliminary Analysis of Chinese GF-3 SAR Quad-Polarization Measurements to Extract Winds in Each Polarization

Directory of Open Access Journals (Sweden)

Lin Ren

2017-11-01

Full Text Available This study analyzed the noise equivalent sigma zero (NESZ and ocean wind sensitivity for Chinese C-band Gaofen-3 (GF-3 quad-polarization synthetic aperture radar (SAR measurements to facilitate further operational wind extraction from GF-3 data. Data from the GF-3 quad-polarization SAR and collocated winds from both NOAA/NCEP Global Forecast System (GFS atmospheric model and National Data Buoy Center (NDBC buoys were used in the analysis. For NESZ, the co-polarization was slightly higher compared to the cross-polarization. Regarding co-polarization and cross-polarization, NESZ was close to RadarSAT-2 and Sentinel-1 A. Wind sensitivity was analyzed by evaluating the dependence on winds in terms of normalized radar cross-sections (NRCS and polarization combinations. The closest geophysical model function (GMF and the polarization ratio (PR model to GF-3 data were determined by comparing data and the model results. The dependence of co-polarized NRCS on wind speed and azimuth angle was consistent with the proposed GMF models. The combination of CMOD5 and CMOD5.N was considered to be the closest GMF in co-polarization. The cross-polarized NRCS exhibited a strong linear relationship with moderate wind speeds higher than 4 m·s−1, but a weak correlation with the azimuth angle. The proposed model was considered as the closest GMF in cross-polarization. For polarization combinations, PR and polarization difference (PD were considered. PR increased only with the incidence angle, whereas PD increased with wind speed and varied with azimuth angle. There were three very close PR models and each can be considered as the closest. Preliminary results indicate that GF-3 quad-polarization data are valid and have the ability to extract winds in each polarization.

[Intermediate energy studies of polarization transfer, polarized deuteron scattering, and (p,π+-) reactions: Rapporteur's report

International Nuclear Information System (INIS)

Moss, J.M.

1985-01-01

An overview of intermediate energy (80 to 1000 MeV) study contributions to the International Polarization Symposium in Osaka, Japan, August 1985 is presented in this report. Contributions fall into three categories: polarization transfer, polarized deuteron scattering and polarized (p,π +- ) reactions

Enhancement of molecular NMR signal induced by polarization transfer from laser-polarized 129Xe

International Nuclear Information System (INIS)

Sun Xianping

2001-01-01

There is a large non-equilibrium nuclear polarization and a longer relaxation time in the laser-polarized 129 Xe produced by means of optical pumping and spin exchange. The characteristics of the laser-polarized 129 Xe permit the transfer of the polarization to enhance the atomic nuclear spin in liquid, solid and surface of solid molecules. Therefore, the sensitivity in nuclear magnetic resonance measurements for the molecules is enhanced and applications in the investigations of materials and surface sciences are expanded. The progress in the investigations of materials and surface sciences are expanded. The progress in the investigations of the polarization transfer between laser-polarized 129 Xe and the atomic nuclei in the molecules, the relative physics and the measurement of some parameters are introduced

Graphics of polar figure; Graficado de figura polar

Energy Technology Data Exchange (ETDEWEB)

Macias B, L.R

1991-11-15

The objective of this work, is that starting from a data file coming from a spectra that has been softened, and of the one that have been generated its coordinates to project it in stereographic form, to create the corresponding polar figure making use of the Cyber computer of the ININ by means of the GRAPHOS package. This work only requires a Beta, Fi and Intensity (I) enter data file. It starts of the existence of a softened spectra of which have been generated already with these data, making use of some language that in this case was FORTRAN for the Cyber computer, a program is generated supported in the Graphos package that allows starting of a reading of the Beta, Fi, I file, to generate the points in a stereographic projection and that it culminates with the graph of the corresponding polar figure. The program will request the pertinent information that is wanted to capture in the polar figure just as: date, name of the enter file, indexes of the polar figure, number of levels, radio of the stereographic projection (cms.), crystalline system to which belongs the sample, name the neuter graph file by create and to add the own general data. (Author)

Airborne Laser Polarization Sensor

Science.gov (United States)

Kalshoven, James, Jr.; Dabney, Philip

1991-01-01

Instrument measures polarization characteristics of Earth at three wavelengths. Airborne Laser Polarization Sensor (ALPS) measures optical polarization characteristics of land surface. Designed to be flown at altitudes of approximately 300 m to minimize any polarizing or depolarizing effects of intervening atmosphere and to look along nadir to minimize any effects depending on look angle. Data from measurements used in conjunction with data from ground surveys and aircraft-mounted video recorders to refine mathematical models used in interpretation of higher-altitude polarimetric measurements of reflected sunlight.

Polarization-preserving holey fibers

DEFF Research Database (Denmark)

Broeng, Jes; Mogilevtsev, Dmitri; Libori, Stig E. Barkou

2001-01-01

In this work we suggest and discuss a microstructure of air capillaries with elliptical cross-section in a tread of glass that gives opportunity for Creation of polarization-preserving fiber with very small beat length between the fundamental modes of different polarization......In this work we suggest and discuss a microstructure of air capillaries with elliptical cross-section in a tread of glass that gives opportunity for Creation of polarization-preserving fiber with very small beat length between the fundamental modes of different polarization...

Development of polarized {sup 3}He filter for polarized neutron experiment

Energy Technology Data Exchange (ETDEWEB)

Sakai, K.; Sato, H.; Yoshimi, A.; Asahi, K. [Tokyo Inst. of Tech. (Japan). Faculty of Science; Masuda, Y.; Muto, S.; Ishimoto, S.; Morimoto, K.

1996-08-01

A high-pressure polarized {sup 3}He gas cell, pumped with two diode lasers, has been developed at KEK for use as a polarizer and a spin analyzer for low energy neutrons. The polarization attained of {sup 3}He was determined through the measurement of the transmission of the unpolarized neutrons through the {sup 3}He cell. So far we obtained P{sub He}=18% at 10 atm and P{sub He}=12% at 20 atm. (author)

Thermal stability study of Cr/Au contact formed on n-type Ga-polar GaN, N-polar GaN, and wet-etched N-polar GaN surfaces

International Nuclear Information System (INIS)

Choi, Yunju; Kim, Yangsoo; Ahn, Kwang-Soon; Kim, Hyunsoo

2014-01-01

Highlights: • The Cr/Au contact on n-type Ga-polar (0 0 0 1) GaN, N-polar (0 0 0 −1) GaN, and wet-etched N-polar GaN were investigated. • Thermal annealing led to a significant degradation of contact formed on N-polar n-GaN samples. • Contact degradation was shown to be closely related to the increase in the electrical resistivity of n-GaN. • Out-diffusion of Ga and N atoms was clearly observed in N-polar samples. - Abstract: The electrical characteristics and thermal stability of a Cr/Au contact formed on n-type Ga-polar (0 0 0 1) GaN, N-polar GaN, and wet-etched N-polar GaN were investigated. As-deposited Cr/Au showed a nearly ohmic contact behavior for all samples, i.e., the specific contact resistance was 3.2 × 10 −3 , 4.3 × 10 −4 , and 1.1 × 10 −3 Ω cm 2 for the Ga-polar, flat N-polar, and roughened N-polar samples, respectively. However, thermal annealing performed at 250 °C for 1 min in a N 2 ambient led to a significant degradation of contact, i.e., the contact resistance increased by 186, 3260, and 2030% after annealing for Ga-polar, flat N-polar, and roughened N-polar samples, respectively. This could be due to the different disruption degree of Cr/Au and GaN interface after annealing, i.e., the insignificant interfacial reaction occurred in the Ga-polar sample, while out-diffusion of Ga and N atoms was clearly observed in N-polar samples

Thermal stability study of Cr/Au contact formed on n-type Ga-polar GaN, N-polar GaN, and wet-etched N-polar GaN surfaces

Energy Technology Data Exchange (ETDEWEB)

Choi, Yunju [School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Suncheon Center, Korea Basic Science Institute, Suncheon 540-742 (Korea, Republic of); Kim, Yangsoo [Suncheon Center, Korea Basic Science Institute, Suncheon 540-742 (Korea, Republic of); Ahn, Kwang-Soon, E-mail: kstheory@ynu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 712-749 (Korea, Republic of); Kim, Hyunsoo, E-mail: hskim7@jbnu.ac.kr [School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

2014-10-30

Highlights: • The Cr/Au contact on n-type Ga-polar (0 0 0 1) GaN, N-polar (0 0 0 −1) GaN, and wet-etched N-polar GaN were investigated. • Thermal annealing led to a significant degradation of contact formed on N-polar n-GaN samples. • Contact degradation was shown to be closely related to the increase in the electrical resistivity of n-GaN. • Out-diffusion of Ga and N atoms was clearly observed in N-polar samples. - Abstract: The electrical characteristics and thermal stability of a Cr/Au contact formed on n-type Ga-polar (0 0 0 1) GaN, N-polar GaN, and wet-etched N-polar GaN were investigated. As-deposited Cr/Au showed a nearly ohmic contact behavior for all samples, i.e., the specific contact resistance was 3.2 × 10{sup −3}, 4.3 × 10{sup −4}, and 1.1 × 10{sup −3} Ω cm{sup 2} for the Ga-polar, flat N-polar, and roughened N-polar samples, respectively. However, thermal annealing performed at 250 °C for 1 min in a N{sub 2} ambient led to a significant degradation of contact, i.e., the contact resistance increased by 186, 3260, and 2030% after annealing for Ga-polar, flat N-polar, and roughened N-polar samples, respectively. This could be due to the different disruption degree of Cr/Au and GaN interface after annealing, i.e., the insignificant interfacial reaction occurred in the Ga-polar sample, while out-diffusion of Ga and N atoms was clearly observed in N-polar samples.

Polarized proton colliders

International Nuclear Information System (INIS)

Roser, T.

1995-01-01

High energy polarized beam collisions will open up the unique physics opportunities of studying spin effects in hard processes. This will allow the study of the spin structure of the proton and also the verification of the many well documented expectations of spin effects in perturbative QCD and parity violation in W and Z production. Proposals for polarized proton acceleration for several high energy colliders have been developed. A partial Siberian Snake in the AGS has recently been successfully tested and full Siberian Snakes, spin rotators, and polarimeters for RHIC are being developed to make the acceleration of polarized beams to 250 GeV possible. This allows for the unique possibility of colliding two 250 GeV polarized proton beams at luminosities of up to 2 x 10 32 cm -2 s -1

Pseudomonas mesophilica and an unnamed taxon, clinical isolates of pink-pigmented oxidative bacteria.

Science.gov (United States)

Gilardi, G L; Faur, Y C

1984-10-01

Twenty-one strains of pink-pigmented bacteria, isolated from human clinical specimens and an environmental source, were compared with Pseudomonas mesophilica ATCC 29983 and Protaminobacter ruber ATCC 8457. These isolates were gram-negative, oxidative rods which were motile by means of a single polar flagellum; gave positive catalase, indophenol oxidase, urease, and amylase reactions; and grew slowly at 30 degrees C. Fourteen isolates conformed to the designated type strains Pseudomonas mesophilica ATCC 29983 and Protaminobacter ruber ATCC 8457. The remaining seven strains represented an undescribed taxon. These pink bacteria appear to be invaders of debilitated patients with an underlying chronic disease.

Prey capture by freely swimming flagellates

Science.gov (United States)

Andersen, Anders; Dolger, Julia; Nielsen, Lasse Tor; Kiorboe, Thomas

2017-11-01

Flagellates are unicellular microswimmers that propel themselves using one or several beating flagella. Here, we explore the dependence of swimming kinematics and prey clearance rate on flagellar arrangement and determine optimal flagellar arrangements and essential trade-offs. To describe near-cell flows around freely swimming flagellates we consider a model in which the cell is represented by a no-slip sphere and each flagellum by a point force. For uniflagellates pulled by a single flagellum the model suggests that a long flagellum favors fast swimming, whereas high clearance rate is favored by a very short flagellum. For biflagellates with both a longitudinal and a transversal flagellum we explore the helical swimming kinematics and the prey capture sites. We compare our predictions with observations of swimming kinematics, prey capture, and flows around common marine flagellates. The Centre for Ocean Life is a VKR Centre of Excellence supported by the Villum Foundation.

Polarization and Persuasion: Integrating the Elaboration Likelihood Model with Explanations of Group Polarization.

Science.gov (United States)

Mongeau, Paul A.

Interest has recently focused on group polarization as a function of attitude processes. Several recent reviewers have challenged polarization researchers to integrate the explanations of polarization to existing theories of attitude change. This review suggests that there exists a clear similarity between the social comparison and persuasive…

Polar bears at risk

Energy Technology Data Exchange (ETDEWEB)

Norris, S.; Rosentrater, L.; Eid, P.M. [WWF International Arctic Programme, Oslo (Norway)

2002-05-01

Polar bears, the world's largest terrestrial carnivore, spend much of their lives on the arctic sea ice. This is where they hunt and move between feeding, denning, and resting areas. The world population, estimated at 22,000 bears, is made up of 20 relatively distinct populations varying in size from a few hundred to a few thousand animals. About 60 per cent of all polar bears are found in Canada. In general, the status of this species is stable, although there are pronounced differences between populations. Reductions in the extent and thickness of sea ice has lead the IUCN Polar Bear Specialist Group to describe climate change as one of the major threats facing polar bears today. Though the long-term effects of climate change will vary in different areas of the Arctic, impacts on the condition and reproductive success of polar bears and their prey are likely to be negative. Longer ice-free periods resulting from earlier break-up of sea ice in the spring and later formation in the fall is already impacting polar bears in the southern portions of their range. In Canada's Hudson Bay, for example, bears hunt on the ice through the winter and into early summer, after which the ice melts completely, forcing bears ashore to fast on stored fat until freeze-up in the fall. The time bears have on the ice to hunt and build up their body condition is cut short when the ice melts early. Studies from Hudson Bay show that for every week earlier that ice break-up occurs, bears will come ashore 10 kg lighter and in poorer condition. It is likely that populations of polar bears dividing their time between land and sea will be severely reduced and local extinctions may occur as greenhouse gas emissions continue to rise and sea ice melts. Expected changes in regional weather patterns will also impact polar bears. Rain in the late winter can cause maternity dens to collapse before females and cubs have departed, thus exposing occupants to the elements and to predators. Such

Asymptotic behaviour in polarized and half-polarized U(1) symmetric vacuum spacetimes

International Nuclear Information System (INIS)

Isenberg, James; Moncrief, Vincent

2002-01-01

We use the Fuchsian algorithm to study the behaviour near the singularity of certain families of U(1) symmetric solutions of the vacuum Einstein equations (with the U(1) isometry group acting spatially). We consider an analytic family of polarized solutions with the maximum number of arbitrary functions consistent with the polarization condition (one of the 'gravitational degrees of freedom' is turned off) and show that all members of this family are asymptotically velocity term dominated (AVTD) as one approaches the singularity. We show that the same AVTD behaviour holds for a family of 'half-polarized' solutions, which is defined by adding one extra arbitrary function to those characterizing the polarized solutions. (The full set of nonpolarized solutions involves two extra arbitrary functions.) Using SL(2, R) Geroch transformations, we produce a further class of U(1) symmetric solutions with AVTD behaviour. We begin to address the issue of whether AVTD behaviour is independent of the choice of time foliation by showing that indeed AVTD behaviour is seen for a wide class of choices of harmonic time in the polarized and half-polarized (U(1) symmetric vacuum) solutions discussed here

The polarization of fast neutrons

International Nuclear Information System (INIS)

Talov, V.V.

2000-01-01

The present work is the review of polarization of fast neutrons and methods of polarization analysis. This also includes information about polarization of fast neutrons from first papers, which described polarization in the D(d,n) 3 He, 7 Li(p,n) 7 Be, and T(p,n) 3 He reactions. (authors)

Elite Polarization and Public Opinion

DEFF Research Database (Denmark)

Robison, Joshua; Mullinix, Kevin

2016-01-01

Elite polarization has reshaped American politics and is an increasingly salient aspect of news coverage within the United States. As a consequence, a burgeoning body of research attempts to unravel the effects of elite polarization on the mass public. However, we know very little about how...... polarization is communicated to the public by news media. We report the results of one of the first content analyses to delve into the nature of news coverage of elite polarization. We show that such coverage is predominantly critical of polarization. Moreover, we show that unlike coverage of politics focused...... on individual politicians, coverage of elite polarization principally frames partisan divisions as rooted in the values of the parties rather than strategic concerns. We build on these novel findings with two survey experiments exploring the influence of these features of polarization news coverage on public...

FDTD simulation of trapping nanowires with linearly polarized and radially polarized optical tweezers.

Science.gov (United States)

Li, Jing; Wu, Xiaoping

2011-10-10

In this paper a model of the trapping force on nanowires is built by three dimensional finite-difference time-domain (FDTD) and Maxwell stress tensor methods, and the tightly focused laser beam is expressed by spherical vector wave functions (VSWFs). The trapping capacities on nanoscale-diameter nanowires are discussed in terms of a strongly focused linearly polarized beam and radially polarized beam. Simulation results demonstrate that the radially polarized beam has higher trapping efficiency on nanowires with higher refractive indices than linearly polarized beam.

Polarization Property Measurement of the Long Undulator Radiation Using Cr/C Multilayer Polarization Elements

International Nuclear Information System (INIS)

Niibe, Masahito; Mukai, Mikihito; Shoji, Yoshihiko; Kimura, Hiroaki

2004-01-01

A rotating analyzer ellipsometry (RAE) system was developed with Cr/C multilayers that function as polarization elements for photon energy range of 110 - 280 eV. Polarization properties of a planar undulator change axisymmetrically in off-axial manner, and the second harmonic is more remarkable for the change. By using the RAE system, the polarization property of the second harmonic radiation from the NewSUBARU long undulator at the energy of 180 eV was examined. The degree of linear polarization of the on-axis radiation was over 0.996. The spatial distribution of the polarization azimuth was measured and was in fair agreement with the theoretical calculation. A peculiar behavior of the polarization property near the radiation peak of the second harmonic was observed by changing the height of the undulator gap

PolarTREC: Successful Methods and Tools for Attaining Broad Educational Impacts with Interdisciplinary Polar Science

Science.gov (United States)

Timm, K. M.; Warburton, J.; Owens, R.; Warnick, W. K.

2008-12-01

PolarTREC--Teachers and Researchers Exploring and Collaborating, a program of the Arctic Research Consortium of the U.S. (ARCUS), is a National Science Foundation (NSF)-funded International Polar Year (IPY) project in which K-12 educators participate in hands-on field experiences in the polar regions, working closely with IPY scientists as a pathway to improving science education. Developing long-term teacher- researcher collaborations through PolarTREC ensures up-to-date climate change science content will permeate the K-12 education system long after the IPY. By infusing education with the cutting edge science from the polar regions, PolarTREC has already shown an increase in student and public knowledge of and interest in the polar regions and global climate change. Preliminary evaluations have shown that PolarTREC's program activities have many positive impacts on educators and their ability to teach science concepts and improve their teaching methods. Additionally, K-12 students polled in interest surveys showed significant changes regarding the importance of understanding the polar regions as a person in today's world. Researchers have been overwhelmingly satisfied with PolarTREC and cited several specific strengths, including the program's crucial link between the teachers' field research experiences and their classroom and the extensive training provided to teachers prior to their expedition. This presentation will focus on other successful components of the PolarTREC program and how researchers and organizations might use these tools to reach out to the public for long-term impacts. Best practices include strategies for working with educators and the development of an internet-based platform for teachers and researchers to interact with the public, combining several communication tools such as online journals and forums, real-time Internet seminars, lesson plans, activities, audio, and other educational resources that address a broad range of scientific

Swimming Motility Mediates the Formation of Neutrophil Extracellular Traps Induced by Flagellated Pseudomonas aeruginosa.

Directory of Open Access Journals (Sweden)

Madison Floyd

2016-11-01

Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen causing severe infections often characterized by robust neutrophilic infiltration. Neutrophils provide the first line of defense against P. aeruginosa. Aside from their defense conferred by phagocytic activity, neutrophils also release neutrophil extracellular traps (NETs to immobilize bacteria. Although NET formation is an important antimicrobial process, the details of its mechanism are largely unknown. The identity of the main components of P. aeruginosa responsible for triggering NET formation is unclear. In this study, our focus was to identify the main bacterial factors mediating NET formation and to gain insight into the underlying mechanism. We found that P. aeruginosa in its exponential growth phase promoted strong NET formation in human neutrophils while its NET-inducing ability dramatically decreased at later stages of bacterial growth. We identified the flagellum as the primary component of P. aeruginosa responsible for inducing NET extrusion as flagellum-deficient bacteria remained seriously impaired in triggering NET formation. Purified P. aeruginosa flagellin, the monomeric component of the flagellum, does not stimulate NET formation in human neutrophils. P. aeruginosa-induced NET formation is independent of the flagellum-sensing receptors TLR5 and NLRC4 in both human and mouse neutrophils. Interestingly, we found that flagellar motility, not flagellum binding to neutrophils per se, mediates NET release induced by flagellated bacteria. Immotile, flagellar motor-deficient bacterial strains producing paralyzed flagella did not induce NET formation. Forced contact between immotile P. aeruginosa and neutrophils restored their NET-inducing ability. Both the motAB and motCD genetic loci encoding flagellar motor genes contribute to maximal NET release; however the motCD genes play a more important role. Phagocytosis of P. aeruginosa and superoxide production by neutrophils were also

The evolution of tensor polarization

International Nuclear Information System (INIS)

Huang, H.; Lee, S.Y.; Ratner, L.

1993-01-01

By using the equation of motion for the vector polarization, the spin transfer matrix for spin tensor polarization, the spin transfer matrix for spin tensor polarization is derived. The evolution equation for the tensor polarization is studied in the presence of an isolate spin resonance and in the presence of a spin rotor, or snake

System for measuring of proton polarization in polarized target

International Nuclear Information System (INIS)

Derkach, A.Ya.; Lukhanin, A.A.; Karnaukhov, I.M.; Kuz'menko, V.S.; Telegin, Yu.N.; Trotsenko, V.I.; Chechetenko, V.F.

1981-01-01

Measurement system of proton polarization in the target, which uses the method of nuclear magnetic resonance is described. To record the signal of NMR-absorption a parallel Q-meter of voltage with analogous subtraction of resonance characteristics of measurement circuit is used. To obtain gradual sensitivity of the system to polarization state in the whole volume of the target the measurement coils is made of tape conductor. The analysis and mathematical modelling of Q-meter are carried out. Corrections for nonlinearity and dispersion are calculated. Key diagrams of the main electron blocks of Q-meter are presented. The system described operates on line with the M6000 computer. Total error of measurement of polarization value of free protons in the target does not exceed 6% [ru

Polarization experiments

International Nuclear Information System (INIS)

Halzen, F.

1977-02-01

In a theoretical review of polarization experiments two important points are emphasized: (a) their versatility and their relevance to a large variety of aspects of hadron physics (tests of basic symmetries; a probe of strong interaction dynamics; a tool for hadron spectroscopy); (b) the wealth of experimental data on polarization parameters in pp and np scattering in the Regge language and in the diffraction language. (author)

Study of Jupiter polarization properties

International Nuclear Information System (INIS)

Bolkvadze, O.R.

1980-01-01

Investigations into polarization properties of the Jupiter reflected light were carried on at the Abastumani astrophysical observatory in 1967, 1968 and 1969 in the four spectral ranges: 4000, 4800, 5400 and 6600 A deg. Data on light polarization in different parts of the Jupiter visible disk are given. Curves of dependence of the planet light polarization degree on a phase angle are plotted. It is shown that in the central part of the visible planet disk the polarization degree is low. Atmosphere is in a stable state in this part of Jupiter. Mean radius of particles of a cloud layer is equal to 0.26μ, and optical thickness of overcloud atmosphere tau=0.05. Height of transition boundary of the cloud layer into overcloud gas atmosphere changes from year to year at the edges of the equatorial zone. Optical thickness of overcloud atmosphere changes also with changing height of a transient layer. The polar Jupiter regions possess a high degree of polarization which depends on a latitude. Polarization increases monotonously with the latitude and over polar regions accepts a maximum value [ru

High energy polarized electron beams

International Nuclear Information System (INIS)

Rossmanith, R.

1987-01-01

In nearly all high energy electron storage rings the effect of beam polarization by synchrotron radiation has been measured. The buildup time for polarization in storage rings is of the order of 10 6 to 10 7 revolutions; the spins must remain aligned over this time in order to avoid depolarization. Even extremely small spin deviations per revolution can add up and cause depolarization. The injection and the acceleration of polarized electrons in linacs is much easier. Although some improvements are still necessary, reliable polarized electron sources with sufficiently high intensity and polarization are available. With the linac-type machines SLC at Stanford and CEBAF in Virginia, experiments with polarized electrons will be possible

Interferometric polarization control

International Nuclear Information System (INIS)

Chuss, David T.; Wollack, Edward J.; Moseley, S. Harvey; Novak, Giles

2006-01-01

We develop the Jones and Mueller matrices for structures that allow control of the path length difference between two linear orthogonal polarizations and consider the effect of placing multiple devices in series. Specifically, we find that full polarization modulation (measurement of Stokes Q, U, and V) can be achieved by placing two such modulators in series if the relative angles of the beam-splitting grids with respect to the analyzer orientation are appropriately chosen. Such a device has several potential advantages over a spinning wave plate modulator for measuring astronomical polarization in the far infrared through millimeter: (i) The use of small, linear motions eliminates the need for cryogenic rotational bearings; (ii) the phase flexibility allows measurement of circular as well as linear polarization; and (iii) this architecture allows for both multiwavelength and broadband modulation. We also present initial laboratory results

Photonic Crystal Polarizing and Non-Polarizing Beam Splitters

International Nuclear Information System (INIS)

Chun-Ying, Guan; Jin-Hui, Shi; Li-Boo, Yuan

2008-01-01

A polarizing beam splitter (PBS) and a non-polarizing beam splitter (NPBS) based on a photonic crystal (PC) directional coupler are demonstrated. The photonic crystal directional coupler consists of a hexagonal lattice of dielectric pillars in air and has a complete photonic band gap. The photonic band structure and the band gap map are calculated using the plane wave expansion (PWE) method. The splitting properties of the splitter are investigated numerically using the finite difference time domain (FDTD) method

Trigonella foenum-graceum (Seed Extract Interferes with Quorum Sensing Regulated Traits and Biofilm Formation in the Strains of Pseudomonas aeruginosa and Aeromonas hydrophila

Directory of Open Access Journals (Sweden)

Fohad Mabood Husain

2015-01-01

Full Text Available Trigonella foenum-graecum L. (Fenugreek is an important plant of the Leguminosae family known to have medicinal properties. However, fraction based antiquorum sensing and antibiofilm activities have not been reported from this plant. In the present study T. foenum-graecum seed extract was sequentially fractionated and sub-MICs were tested for above activities. The methanol fraction of the extract demonstrated significant inhibition of AHL regulated virulence factors: protease, LasB elastase, pyocyanin production, chitinase, EPS, and swarming motility in Pseudomonas aeruginosa PAO1 and PAF79. Further, QS dependent virulence factor in the aquatic pathogen Aeromonas hydrophila WAF38 was also reduced. Application of T. foenum-graecum seed extract to PAO1, PAF79, and WAF38 decreased the biofilm forming abilities of the pathogens by significant levels. The extract also exhibited reduced AHL levels and subsequent downregulation of lasB gene. In vivo study showed an enhanced survival of PAO1-preinfected C. elegans after treatment with extract at 1 mg/mL. Further, the major compound detected by GC-MS, caffeine, reduced the production of QS regulated virulence factors and biofilm at 200 µg/mL concentration indicating its role in the activity of the methanol extract. The results of the present study reveal the potential anti-QS and antibiofilm property of T. foenum-graceum extract and caffeine.

Recent results on polarizations and the present status of the Fermilab polarized beams

International Nuclear Information System (INIS)

Yokosawa, Akihiko.

1986-01-01

Experimental results are reviewed on polarization phenomena in nucleon-nucleon scattering at intermediate energies. The present status of S = 0 dibaryon resonances is presented. The status of the Fermilab polarized beam program is presented, including the construction of polarized beam, two polarimeters being installed in the experimental hall, and the experimental program

Reciprocal and dynamic polarization of planar cell polarity core components and myosin

Science.gov (United States)

Newman-Smith, Erin; Kourakis, Matthew J; Reeves, Wendy; Veeman, Michael; Smith, William C

2015-01-01

The Ciona notochord displays planar cell polarity (PCP), with anterior localization of Prickle (Pk) and Strabismus (Stbm). We report that a myosin is polarized anteriorly in these cells and strongly colocalizes with Stbm. Disruption of the actin/myosin machinery with cytochalasin or blebbistatin disrupts polarization of Pk and Stbm, but not of myosin complexes, suggesting a PCP-independent aspect of myosin localization. Wash out of cytochalasin restored Pk polarization, but not if done in the presence of blebbistatin, suggesting an active role for myosin in core PCP protein localization. On the other hand, in the pk mutant line, aimless, myosin polarization is disrupted in approximately one third of the cells, indicating a reciprocal action of core PCP signaling on myosin localization. Our results indicate a complex relationship between the actomyosin cytoskeleton and core PCP components in which myosin is not simply a downstream target of PCP signaling, but also required for PCP protein localization. DOI: http://dx.doi.org/10.7554/eLife.05361.001 PMID:25866928

[Biofilm Formation by the Nonflagellated flhB1 Mutant of Azospirillum brasilense Sp245].

Science.gov (United States)

Shelud'ko, A V; Filip'echeva, Yu A; Shumiliva, E M; Khlebtsov, B N; Burov, A M; Petrova, L P; Katsy, E I

2015-01-01

Azospirillum brasilense Sp245 with mixed flagellation are able to form biofilms on various surfaces. A nonflagellated mutant of this strain with inactivated chromosomal copy of the flhB gene (flhB1) was shown to exhibit specific traits at the later stages of biofilm formation on a hydrophilic (glass) surface. Mature biofilms of the flhB1::Omegon-Km mutant Sp245.1063 were considerably thinner than those of the parent strain Sp245. The biofilms of the mutant were more susceptible to the forces of hydrodynamic shear. A. brasilense Sp245 cells in biofilms were not found to possess lateral flagella. Cells with polar flagella were, however, revealed by atomic force microscopy of mature native biofilms of strain Sp245. Preservation of a polar flagellum (probably nonmotile) on the cells of A. brasilense Sp245 may enhance the biofilm stability.

Polarization transfer from polarized nuclear spin to μ- spin in muonic atom

International Nuclear Information System (INIS)

Kuno, Yoshitaka; Nagamine, Kanetada; Yamazaki, Toshimitsu.

1987-02-01

A theoretical study of polarization transfer from an initially-polarized nuclear spin to a μ - spin in a muonic atom is given. The switching of the hyperfine interaction at excited muonic states as well as at the ground 1s state is taken into account. The upper state of hyperfine doublet at the muonic 1s state is considered to proceed down to the lower state. It is found that as the hyperfine interaction becomes effective at higher excited muonic orbitals, a less extent of polarization is transferred from the nuclear spin to the μ - spin. The theoretical values obtained are compared with the recent experiment of μ - repolarization in a polarized 209 Bi target. (author)

Polarized proton beams since the ZGS

International Nuclear Information System (INIS)

Krisch, A.D.

1994-01-01

The author discusses research involving polarized proton beams since the ZGS's demise. He begins by reminding the attendee that in 1973 the ZGS accelerated the world's first high energy polarized proton beam; all in attendance at this meeting can be proud of this accomplishment. A few ZGS polarized proton beam experiments were done in the early 1970's; then from about 1976 until 1 October 1979, the majority of the ZGS running time was polarized running. A great deal of fundamental physics was done with the polarized beam when the ZGS ran as a dedicated polarized proton beam from about Fall 1977 until it shut down on 1 October 1979. The newly created polarization enthusiats then dispersed; some spread polarized seeds al over the world by polarizing beams elsewhere; some wound up running the High Energy and SSC programs at DOE

Polarization Optics in Telecommunications

CERN Document Server

Damask, Jay N

2005-01-01

The strong investments into optical telecommunications in the late 1990s resulted in a wealth of new research, techniques, component designs, and understanding of polarization effects in fiber. Polarization Optics in Telecommunications brings together recent advances in the field to create a standard, practical reference for component designers and optical fiber communication engineers. Beginning with a sound foundation in electromagnetism, the author offers a dissertation of the spin-vector formalism of polarization and the interaction of light with media. Applications discussed include optical isolators, optical circulators, fiber collimators, and a variety of applied waveplate and prism combinations. Also included in an extended discussion of polarization-mode dispersion (PMD) and polarization-dependent loss (PDL), their representation, behavior, statistical properties, and measurement. This book draws extensively from the technical and patent literature and is an up-to-date reference for researchers and c...

Electroproduction of polarized Λ's

International Nuclear Information System (INIS)

Kunne, R.A.

1992-01-01

Lambdas are a powerful tool to explore spin effects of QCD. The λ polarization is self analyzing, as it is measurable from the angular distribution of the decay products. Two applications of polarized electroproduced λ's are suggested: the measurement of λ polarization at large transverse momentum as a possible test of QCD and the measurement of transversely polarized parton distributions

Polarized proton collider at RHIC

International Nuclear Information System (INIS)

Alekseev, I.; Allgower, C.; Bai, M.; Batygin, Y.; Bozano, L.; Brown, K.; Bunce, G.; Cameron, P.; Courant, E.; Erin, S.; Escallier, J.; Fischer, W.; Gupta, R.; Hatanaka, K.; Huang, H.; Imai, K.; Ishihara, M.; Jain, A.; Lehrach, A.; Kanavets, V.; Katayama, T.; Kawaguchi, T.; Kelly, E.; Kurita, K.; Lee, S.Y.; Luccio, A.; MacKay, W.W.; Mahler, G.; Makdisi, Y.; Mariam, F.; McGahern, W.; Morgan, G.; Muratore, J.; Okamura, M.; Peggs, S.; Pilat, F.; Ptitsin, V.; Ratner, L.; Roser, T.; Saito, N.; Satoh, H.; Shatunov, Y.; Spinka, H.; Syphers, M.; Tepikian, S.; Tominaka, T.; Tsoupas, N.; Underwood, D.; Vasiliev, A.; Wanderer, P.; Willen, E.; Wu, H.; Yokosawa, A.; Zelenski, A.N.

2003-01-01

In addition to heavy ion collisions (RHIC Design Manual, Brookhaven National Laboratory), RHIC will also collide intense beams of polarized protons (I. Alekseev, et al., Design Manual Polarized Proton Collider at RHIC, Brookhaven National Laboratory, 1998, reaching transverse energies where the protons scatter as beams of polarized quarks and gluons. The study of high energy polarized protons beams has been a long term part of the program at BNL with the development of polarized beams in the Booster and AGS rings for fixed target experiments. We have extended this capability to the RHIC machine. In this paper we describe the design and methods for achieving collisions of both longitudinal and transverse polarized protons in RHIC at energies up to √s=500 GeV

Optical properties of polarization-dependent geometrical phase elements with partially polarized light

International Nuclear Information System (INIS)

Gorodetski, Y.; Biener, G.; Niv, A.; Kleiner, V.; Hasman, E.

2005-01-01

Full Text:The behavior of geometrical phase elements illuminated with partially polarized monochromatic beams is being theoretically as well as experimentally investigated. The element discussed in this paper is composed of wave plates with retardation and space-variant orientation angle. We found that a beam emerging from such an element comprises two polarization orders of right and left-handed circularly polarized states with conjugate geometrical phase modification. This phase equals twice the orientation angle of the space-variant wave plate comprising the element. Apart from the two polarization orders, the emerging beam coherence polarization matrix comprises a matrix termed as the vectorial interference matrix. This matrix contains the information concerning the correlation between the two orthogonal circularly polarized portions of the incident beam. In this paper we measure this correlation by a simple interference experiment. Furthermore, we found that the equivalent mutual intensity of the emerging beam is being modulated according to the geometrical phase induced by the element. Other interesting phenomena along propagation will be discussed theoretically and experimentally demonstrated. We demonstrate experimentally our analysis by using a spherical geometrical phase element, which is realized by use of space-variant sub wavelength grating and illuminated with a CO 2 laser radiation of 10.6μm wavelength

POLARIZED BEAMS: 2 - Partial Siberian Snake rescues polarized protons at Brookhaven

International Nuclear Information System (INIS)

Huang, Haixin

1994-01-01

To boost the level of beam polarization (spin orientation), a partial 'Siberian Snake' was recently used to overcome imperfection depolarizing resonances in the Brookhaven Alternating Gradient Synchrotron (AGS). This 9-degree spin rotator recently permitted acceleration with no noticeable polarization loss. The intrinsic AGS depolarizing resonances (which degrade the polarization content) had been eliminated by betatron tune jumps, but the imperfection resonances were compensated by means of harmonic orbit corrections. However, at high energies these orbit corrections are difficult and tedious and a Siberian Snake became an attractive alternative

Nuclear physics with polarized particles

CERN Document Server

Paetz gen Schieck, Hans

2012-01-01

The measurement of spin-polarization observables in reactions of nuclei and particles is of great utility and advantage when the effects of single-spin sub-states are to be investigated. Indeed, the unpolarized differential cross-section encompasses the averaging over the spin states of the particles, and thus loses details of the interaction process. This introductory text combines, in a single volume, course-based lecture notes on spin physics and on polarized-ion sources with the aim of providing a concise yet self-contained starting point for newcomers to the field, as well as for lecturers in search of suitable material for their courses and seminars. A significant part of the book is devoted to introducing the formal theory-a description of polarization and of nuclear reactions with polarized particles. The remainder of the text describes the physical basis of methods and devices necessary to perform experiments with polarized particles and to measure polarization and polarization effects in nuclear rea...

The polarization of fast neutrons

International Nuclear Information System (INIS)

Talov, V.V.

2001-01-01

It is insufficient to know coordinates and momentum to describe a state of a neutron. It is necessary to define a spin orientation. As far as it is known from quantum mechanics, a half spin has a projection in the positive direction or in the negative direction. The probability of both projections in an unpolarized beam is equal. If a direction exists, in which the projection is more probably then beam is called polarized in this direction. It is essential to know polarization of neutrons for characteristics of a neutron source, which is emitting it. The question of polarization of fast neutrons came up in 50's. The present work is the review of polarization of fast neutrons and methods of polarization analysis. This also includes information about polarization of fast neutrons from first papers, which described polarization in the D(d,n) 3 He, 7 Li (p,n) 7 Be, T(p,n) 3 He reactions. (authors)

Stanford polarized atomic beam target

International Nuclear Information System (INIS)

Mavis, D.G.; Dunham, J.S.; Hugg, J.W.; Glavish, H.F.

1976-01-01

A polarized atomic beam source was used to produce an atomic hydrogen beam which was in turn used as a polarized proton target. A target density of 2 x 10'' atoms/cm 3 and a target polarization of 0.37 without the use of rf transitions were measured. These measurements indicate that a number of experiments are currently feasible with a variety of polarized target beams

Solar Spectral Lines with Special Polarization Properties for the Calibration of Instrument Polarization

Energy Technology Data Exchange (ETDEWEB)

Li, W.; Casini, R.; Alemán, T. del Pino; Judge, P. G. [High Altitude Observatory, National Center for Atmospheric Research 1, P.O. Box 3000, Boulder, CO 80307-3000 (United States)

2017-10-20

We investigate atomic transitions that have previously been identified as having zero polarization from the Zeeman effect. Our goal is to identify spectral lines that can be used for the calibration of instrumental polarization of large astronomical and solar telescopes, such as the Daniel K. Inouye Solar Telescope, which is currently under construction on Haleakala. We use a numerical model that takes into account the generation of scattering polarization and its modification by the presence of a magnetic field of arbitrary strength. We adopt values for the Landé factors from spectroscopic measurements or semi-empirical results, thus relaxing the common assumption of LS-coupling previously used in the literature. The mechanisms dominating the polarization of particular transitions are identified, and we summarize groups of various spectral lines useful for the calibration of spectropolarimetric instruments, classified according to their polarization properties.

Polar transport in plants mediated by membrane transporters: focus on mechanisms of polar auxin transport.

Science.gov (United States)

Naramoto, Satoshi

2017-12-01

Directional cell-to-cell transport of functional molecules, called polar transport, enables plants to sense and respond to developmental and environmental signals. Transporters that localize to plasma membranes (PMs) in a polar manner are key components of these systems. PIN-FORMED (PIN) auxin efflux carriers, which are the most studied polar-localized PM proteins, are implicated in the polar transport of auxin that in turn regulates plant development and tropic growth. In this review, the regulatory mechanisms underlying polar localization of PINs, control of auxin efflux activity, and PIN abundance at PMs are considered. Up to date information on polar-localized nutrient transporters that regulate directional nutrient movement from soil into the root vasculature is also discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Parallel Polarization State Generation.

Science.gov (United States)

She, Alan; Capasso, Federico

2016-05-17

The control of polarization, an essential property of light, is of wide scientific and technological interest. The general problem of generating arbitrary time-varying states of polarization (SOP) has always been mathematically formulated by a series of linear transformations, i.e. a product of matrices, imposing a serial architecture. Here we show a parallel architecture described by a sum of matrices. The theory is experimentally demonstrated by modulating spatially-separated polarization components of a laser using a digital micromirror device that are subsequently beam combined. This method greatly expands the parameter space for engineering devices that control polarization. Consequently, performance characteristics, such as speed, stability, and spectral range, are entirely dictated by the technologies of optical intensity modulation, including absorption, reflection, emission, and scattering. This opens up important prospects for polarization state generation (PSG) with unique performance characteristics with applications in spectroscopic ellipsometry, spectropolarimetry, communications, imaging, and security.

Polarized deuteron elastic scattering from a polarized proton target

International Nuclear Information System (INIS)

Schmelzer, R.; Kuiper, H.; Schoeberl, M.; Berber, S.; Hilmert, H.; Koeppel, R.; Pferdmenges, R.; Zankel, H.

1983-01-01

Measurements are reported of the spin correlation parameter Cy,y for the elastic scattering of 10.0 MeV vector polarized deuterons from a polarized proton target at five CM angles (76 0 ,85 0 ,98 0 ,115 0 ,132 0 ). The experimental results are compared with different predictions. A Faddeev type calculation on the basis of local potentials also including approximate Coulomb distortion is favoured by our experimental results. (orig.)

Polarized vacuum ultraviolet and X-radiation

International Nuclear Information System (INIS)

Samson, J.A.R.

1978-01-01

The most intense source of polarized vacuum UV and X-radiation is synchrotron radiation, which exhibits a degree of partially polarized light between about 80-100%. However, the radiation transmitted by vacuum UV monochromators can also be highly polarized. The Seya-Namioka type of monochromator can produce partially polarized radiation between 50-80%. For certain experiments it is necessary to know the degree of polarisation of the radiation being used. Also, when synchrotron radiation and a monochromator are combined the polarization characteristic of both should be known in order to make full use of these polarization properties. The polarizing effect on monochromators (i.e. diffraction gratings) have been measured at the Seya angle and at grazing angles for various spectral orders. The author presents the first experimental evidence that the reciprocity law holds for polarization by reflection where the angle of incidence and diffraction are unequal. These results are reviewed along with the techniques for measuring the degree of polarization. (Auth.)

Spin-polarized photoemission

International Nuclear Information System (INIS)

Johnson, Peter D.

1997-01-01

Spin-polarized photoemission has developed into a versatile tool for the study of surface and thin film magnetism. In this review, we examine the methodology of the technique and its application to a number of different problems, including both valence band and core level studies. After a detailed review of spin-polarization measurement techniques and the related experimental requirements we consider in detail studies of the bulk properties both above and below the Curie temperature. This section also includes a discussion of observations relating to unique metastable phases obtained via epitaxial growth. The application of the technique to the study of surfaces, both clean and adsorbate covered, is reviewed. The report then examines, in detail, studies of the spin-polarized electronic structure of thin films and the related interfacial magnetism. Finally, observations of spin-polarized quantum well states in non-magnetic thin films are discussed with particular reference to their mediation of the oscillatory exchange coupling in related magnetic multilayers. (author)

A review of polarized ion sources

International Nuclear Information System (INIS)

Schmor, P.W.

1995-06-01

The two main types of polarized ion sources in use on accelerators today are the Atomic Beam Polarized Ion Source (ABIS) source and the Optically Pumped Polarized Ion Source (OPPIS). Both types can provide beams of nuclearly polarized light ions which are either positively or negatively charged. Heavy ion polarized ion sources for accelerators are being developed. (author). 35 refs., 1 tab

Polarization phenomena in heavy-ion reactions

International Nuclear Information System (INIS)

Sugimoto, K.; Ishihara, M.; Takahashi, N.

1984-01-01

This chapter presents a few key experiments which provide direct evidence of the polarization phenomena in heavy-ion reactions. The theory of polarization observables and measurements is given with the necessary formulae. The polarization phenomena is described and studies of product nuclear polarization in heavy-ion reactions are discussed. Studies of heavy-ion reactions induced by polarized beams are examined

Dynamic nuclear polarization tests in some polymers for polarized targets

International Nuclear Information System (INIS)

Brandt, B. van den; Hautle, P.; Konter, J.A.; Mango, S.; Bunyatova, E.I.

1998-01-01

The results of dynamic polarization tests in polyethylene (PE) and ethylene propylene copolymer (EPC), doped with the stable free radical 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), are presented. Sizable proton polarizations have been achieved in a magnetic field of 2.5 T at a temperature below 0.3 K and 5T at 1 K

Broad-aperture polarized proton target with arbitrary orientation of polarization vector

International Nuclear Information System (INIS)

Belyaev, A.A.; Get'man, V.A.; Derkach, A.Ya.; Karnaukhov, I.M.; Lukhanin, A.A.; Razumnyj, A.A.; Sorokin, P.V.; Sporov, E.A.; Telegin, Yu.N.; Trotsenko, V.I.

1985-01-01

Polarized proton target with the Helmholtz broad-aperture superconducting magnetic system is described. Axial aperture α=95 deg, inter-coil access angle β=23 deg. The structure of the target allows various versions of the installation what make sure an arbitrary orientation of polarization vector. The 0.1 W cold output 3 He evaporation cryostat was used to obtain the work temperature 0.5 K allowing quick transformation to a 3 He- 4 He dilution refrigerator. Results of the study are given on the dynamical proton polarization in 1,2-propylenglycol with various stable Cr 5 complexes

Do embryonic polar bodies commit suicide?

Science.gov (United States)

Fabian, Dušan; Čikoš, Štefan; Rehák, Pavol; Koppel, Juraj

2014-02-01

The extrusion and elimination of unnecessary gametic/embryonic material is one of the key events that determines the success of further development in all living organisms. Oocytes produce the first polar body to fulfill the maturation process just before ovulation, and release the second polar body immediately after fertilization. The aim of this study was to compile a physiological overview of elimination of polar bodies during early preimplantation development in mice. Our results show that three-quarters of the first polar bodies were lost even at the zygotic stage; the 4-cell stage embryos contained only one (second) polar body, and the elimination of second polar bodies proceeded continuously during later development. Both first and second polar bodies showed several typical features of apoptosis: phosphatidylserine redistribution (observed for the first time in the first polar body), specific DNA degradation, condensed nuclear morphology, and inability to exclude cationic dye from the nucleus during the terminal stage of the apoptotic process. Caspase-3 activity was recorded only in the second polar body. From the morphological point of view, mouse polar bodies acted very similarly to damaged embryonic cells which have lost contact with their neighboring blastomeres. In conclusion, polar bodies possess all the molecular equipment necessary for triggering and executing an active suicide process. Furthermore, similarly as in dying embryonic cells, stressing external conditions (culture in vitro) might accelerate and increase the incidence of apoptotic elimination of the polar bodies in embryos.

Spin exchange in polarized deuterium

International Nuclear Information System (INIS)

Przewoski, B. von; Meyer, H.O.; Balewski, J.; Doskow, J.; Ibald, R.; Pollock, R.E.; Rinckel, T.; Wellinghausen, A.; Whitaker, T.J.; Daehnick, W.W.; Haeberli, W.; Schwartz, B.; Wise, T.; Lorentz, B.; Rathmann, F.; Pancella, P.V.; Saha, Swapan K.; Thoerngren-Engblom, P.

2003-01-01

We have measured the vector and tensor polarization of an atomic deuterium target as a function of the target density. The polarized deuterium was produced in an atomic beam source and injected into a storage cell. For this experiment, the atomic beam source was operated without rf transitions, in order to avoid complications from the unknown efficiency of these transitions. In this mode, the atomic beam is vector and tensor polarized and both polarizations can be measured simultaneously. We used a 1.2-cm-diam and 27-cm-long storage cell, which yielded an average target density between 3 and 9x10 11 at/cm 3 . We find that the tensor polarization decreases with increasing target density while the vector polarization remains constant. The data are in quantitative agreement with the calculated effect of spin exchange between deuterium atoms at low field

Study by polarized muon

International Nuclear Information System (INIS)

Yamazaki, Toshimitsu

1977-01-01

Experiments by using polarized muon beam are reported. The experiments were performed at Berkeley, U.S.A., and at Vancouver, Canada. The muon spin rotation is a useful method for the study of the spin polarization of conductive electrons in paramagnetic Pd metal. The muon Larmor frequency and the relaxation time can be obtained by measuring the time distribution of decay electrons of muon-electron process. The anomalous depolarization of negative muon spin rotation in the transitional metal was seen. The circular polarization of the negative muon X-ray was measured to make clear this phenomena. The experimental results show that the anomalous depolarization is caused at the 1-S-1/2 state. For the purpose to obtain the strong polarization of negative muon, a method of artificial polarization is proposed, and the test experiments are in progress. The study of the hyperfine structure of mu-mesic atoms is proposed. The muon capture rate was studied systematically. (Kato, T.)

ACCELERATION OF POLARIZED PROTONS AT RHIC

International Nuclear Information System (INIS)

HUANG, H.

2002-01-01

Relativistic Heavy Ion Collider (RHIC) ended its second year of operation in January 2002 with five weeks of polarized proton collisions. Polarized protons were successfully injected in both RHIC rings and maintained polarization during acceleration up to 100 GeV per ring using two Siberian snakes in each ring. This is the first time that polarized protons have been accelerated to 100 GeV. The machine performance and accomplishments during the polarized proton run will be reviewed. The plans for the next polarized proton run will be outlined

Polarized deuteron elastic scattering from a polarized proton target

Energy Technology Data Exchange (ETDEWEB)

Schmelzer, R.; Kuiper, H.; Schoeberl, M.; Berber, S.; Hilmert, H.; Koeppel, R.; Pferdmenges, R. (Erlangen-Nuernberg Univ., Erlangen (Germany, F.R.). Physikalisches Inst.); Zankel, H. (Graz Univ. (Austria). Inst. fuer Theoretische Physik)

1983-01-13

Measurements are reported of the spin correlation parameter Cy,y for the elastic scattering of 10.0 MeV vector polarized deuterons from a polarized proton target at five CM angles (76/sup 0/,85/sup 0/,98/sup 0/,115/sup 0/,132/sup 0/). The experimental results are compared with different predictions. A Faddeev type calculation on the basis of local potentials also including approximate Coulomb distortion is favoured by our experimental results.

The Polarization of Achernar

Science.gov (United States)

McDavid, D.

2005-11-01

Recent near-infrared measurements of the angular diameter of Achernar (the bright Be star alpha Eridani) with the ESO VLT interferometer have been interpreted as the detection of an extremely oblate photosphere, with a ratio of equatorial to polar radius of at least 1.56 ± 0.05 and a minor axis orientation of 39° ± 1° (from North to East). The optical linear polarization of this star during an emission phase in 1995 September was 0.12 ± 0.02% at position angle 37° ± 8° (in equatorial coordinates), which is the direction of the projection of the rotation axis on the plane of the sky according to the theory of polarization by electron scattering in an equatorially flattened circumstellar disk. These two independent determinations of the orientation of the rotation axis are therefore in agreement. The observational history of correlations between Hα emission and polarization as found in the literature is that of a typical Be star, with the exception of an interesting question raised by the contrast between Schröder's measurement of a small polarization perpendicular to the projected rotation axis in 1969--70 and Tinbergen's measurement of zero polarization in 1974.5, both at times when emission was reportedly absent.

Polarization-Insensitive Surface Plasmon Polarization Electro-Absorption Modulator Based on Epsilon-Near-Zero Indium Tin Oxide

Science.gov (United States)

Jin, Lin; Wen, Long; Liang, Li; Chen, Qin; Sun, Yunfei

2018-02-01

CMOS-compatible plasmonic modulators operating at the telecom wavelength are significant for a variety of on-chip applications. Relying on the manipulation of the transverse magnetic (TM) mode excited on the metal-dielectric interface, most of the previous demonstrations are designed to response only for specific polarization state. In this case, it will lead to a high polarization dependent loss, when the polarization-sensitive modulator integrates to a fiber with random polarization state. Herein, we propose a plasmonic modulator utilizing a metal-oxide indium tin oxide (ITO) wrapped around the silicon waveguide and investigate its optical modulation ability for both the vertical and horizontal polarized guiding light by tuning electro-absorption of ITO with the field-induced carrier injection. The electrically biased modulator with electron accumulated at the ITO/oxide interface allows for epsilon-near-zero (ENZ) mode to be excited at the top or lateral portion of the interface depending on the polarization state of the guiding light. Because of the high localized feature of ENZ mode, efficient electro-absorption can be achieved under the "OFF" state of the device, thus leading to large extinction ratio (ER) for both polarizations in our proposed modulator. Further, the polarization-insensitive modulation is realized by properly tailoring the thickness of oxide in two different stacking directions and therefore matching the ER values for device operating at vertical and horizontal polarized modes. For the optimized geometry configuration, the difference between the ER values of two polarization modes, i.e., the ΔER, as small as 0.01 dB/μm is demonstrated and, simultaneously with coupling efficiency above 74%, is obtained for both polarizations at a wavelength of 1.55 μm. The proposed plasmonic-combined modulator has a potential application in guiding and processing of light from a fiber with a random polarization state.

Optically pumped electron spin polarized targets for use in the production of polarized ion beams

International Nuclear Information System (INIS)

Anderson, L.W.

1979-01-01

The production of relatively dense electron spin polarized alkali metal vapor targets by optical pumping with intense cw dye lasers is discussed. The target density and electron spin polarization depend on the dye laser intensity and bandwidth, the magnetic field at the target, and the electron spin depolarization time. For example in a magnetic field of 1.5 x 10 3 G, and using 1 W dye laser with a bandwidth of 10 10 Hz one can construct an electron spin polarized Na vapor target with a target thickness of 1.6 x 10 13 atoms/cm 2 and an average electron spin polarization of about 90% even though the Na atoms are completely depolarized at every wall collision. Possible uses of the electron spin polarized targets for the production of intense beams of polarized H - or 3 He - ions are discussed. (orig.)

Design of a tensor polarized deuterium target polarized by spin-exchange with optically pumped NA

International Nuclear Information System (INIS)

Green, M.C.

1984-01-01

A proposed design for a tensor polarized deuterium target (approx. 10 15 atoms/cm 2 ) for nuclear physics studies in an electron storage ring accelerator is presented. The deuterium atoms undergo electron spin exchange with a highly polarized sodium vapor; this polarization is transferred to the deuterium nuclei via the hyperfine interaction. The deuterium nuclei obtain their tensor polarization through repeated electron spin exchange/hyperfine interactions. The sodium vapor polarization is maintained by standard optical pumping techniques. Model calculations are presented in detail leading to a discussion of the expected performance and the technical obstacles to be surmounted in the development of such a target

Design of a tensor polarized deuterium target polarized by spin-exchange with optically pumped NA

International Nuclear Information System (INIS)

Green, M.C.

1984-05-01

A proposed design for a tensor polarized deuterium target (approx. 10 15 atoms/cm 2 ) for nuclear physics studies in an electron storage ring accelerator is presented. The deuterium atoms undergo electron spin exchange with a highly polarized sodium vapor; this polarization is transferred to the deuterium nuclei via the hyperfine interaction. The deuterium nuclei obtain their tensor polarization through repeated electron spin exchange/hyperfine interactions. The sodium vapor polarization is maintained by standard optical pumping techniques. Model calculations are presented in detail leading to a discussion of the expected performance and the technical obstacles to be surmounted in the development of such a target. 15 references, 10 figures

Sources of linear polarized x-rays

International Nuclear Information System (INIS)

Aiginger, H.; Wobrauschek, P.

1989-01-01

Linear polarized X-rays are used in X-ray fluorescence analysis to decrease the background caused by scattered photons. Various experiments, calculations and constructions have demonstrated the possibility to produce polarized radiation in an analytical laboratory with an X-ray tube and polarizer-analyzer facilities as auxiliary equipment. The results obtained with Bragg-polarizers of flat and curved focussing geometry and of Barkla-polarizers are presented. The advantages and disadvantages of the method are discussed and compared with the respective quality of synchrotron radiation. Polarization by scattering reduces the intensity of the primary radiation. Recently much effort is devoted to the construction of integrated high power X-ray tube polarizer-analyzer arrangements. The detailed design, geometry and performance of such a facility is described. (author)

Physics with polarized electron beams

International Nuclear Information System (INIS)

Swartz, M.L.

1988-01-01

As a distinct field, elementary particle physics is now approximately forty years old. In all that time, only a few of the thousands of experiments that have been performed have made use of spin polarized particle beams (with apologies to those who have studied neutrino interactions, polarized beam are defined to refer to the case in which the experimenter has control over the polarization direction). If the discussion is restricted to spin polarized electron beams, the number of experiments becomes countable with the fingers of one hand (with several to spare). There are two reasons for this lack of interest. The first is that spin polarized beams are difficult to produce, accelerate, and transport. The second reason is that any physical process that can occur during the collision of a polarized particle with another (polarized or not) can also occur during the collision of unpolarized particles. One might ask then, why has any effort been expended on the subject. The answer, at least in the case of polarized electron beams, is that electron accelerators and storage rings have in recent years achieved sufficient energy to begin to probe the weak interaction directly. The weak interaction distinguishes between left- and right-handed fermionic currents. Left-handed particles interact in a fundamentally different way than their right-handed counterparts. If the experimenter wishes to explore or exploit this difference, he (or she) must either prepare the spin state of the incident particles or analyze the spin state of outgoing particles. For reasons of genearlity and improved statistical precision, the former is usually preferable to the latter. The first of these lectures will review some of the techniques necessary for the production, transport, and monitoring of polarized electron (or positron) beams. The second lecture will survey some of the physics possibilities of polarized electron-positron collisions

Multiphoton polarization Bremsstrahlung effect

International Nuclear Information System (INIS)

Golovinskij, P.A.

2001-01-01

A general approach to induced polarization effects was formulated on the basis of theory of many particles in a strong periodic field. Correlation with the perturbation theory is shown and the types of effective polarization potentials both for isolated atoms and ions, and for ions in plasma, are provided. State of art in the theory of forced polarization Bremsstrahlung effect is analyzed and some outlooks for further experimental and theoretical studies are outlined [ru

EDITORIAL: Non-polar and semipolar nitride semiconductors Non-polar and semipolar nitride semiconductors

Science.gov (United States)

Han, Jung; Kneissl, Michael

2012-02-01

Throughout the history of group-III-nitride materials and devices, scientific breakthroughs and technological advances have gone hand-in-hand. In the late 1980s and early 1990s, the discovery of the nucleation of smooth (0001) GaN films on c-plane sapphire and the activation of p-dopants in GaN led very quickly to the realization of high-brightness blue and green LEDs, followed by the first demonstration of GaN-based violet laser diodes in the mid 1990s. Today, blue InGaN LEDs boast record external quantum efficiencies exceeding 80% and the emission wavelength of the InGaN-based laser diode has been pushed into the green spectral range. Although these tremenduous advances have already spurred multi-billion dollar industries, there are still a number of scientific questions and technological issues that are unanswered. One key challenge is related to the polar nature of the III-nitride wurtzite crystal. Until a decade ago all research activities had almost exclusively concentrated on (0001)-oriented polar GaN layers and heterostructures. Although the device characteristics seem excellent, the strong polarization fields at GaN heterointerfaces can lead to a significant deterioration of the device performance. Triggered by the first demonstration non-polar GaN quantum wells grown on LiAlO2 by Waltereit and colleagues in 2000, impressive advances in the area of non-polar and semipolar nitride semiconductors and devices have been achieved. Today, a large variety of heterostructures free of polarization fields and exhibiting exceptional electronic and optical properties have been demonstrated, and the fundamental understanding of polar, semipolar and non-polar nitrides has made significant leaps forward. The contributions in this Semiconductor Science and Technology special issue on non-polar and semipolar nitride semiconductors provide an impressive and up-to-date cross-section of all areas of research and device physics in this field. The articles cover a wide range of

VAKSINASI IKAN TILAPIA (Oreochromis niloticus MENGGUNAKAN VAKSIN MONOVALEN DAN BIVALEN UNTUK PENCEGAHAN PENYAKIT MOTILE AEROMONAS SEPTICEMIA DAN STREPTOCOCCOSIS

Directory of Open Access Journals (Sweden)

Desy Sugiani

2013-08-01

Full Text Available Peningkatan respon antibodi pascavaksinasi dengan antigen tunggal dan campuran dari bakterin Aeromonas hydrophila and Streptococcus agalactiae diharapkan dapat meningkatkan daya tahan ikan tilapia (Oreochromis niloticus terhadap penyakit Motile Aeromonas Septicemia/MAS dan Streptococcosis. Sediaan vaksin disiapkan dengan metode pembuatan dan formula yang berbeda, proses inaktifasi dilakukan dengan menambahkan 3% Neutral Buffer Formalin (NBF 10% pada biakan bakteri dalam media tumbuh BHI dan TSB. Vaksinasi diberikan melalui injeksi intraperitoneal dengan sediaan vaksin monovalen A. hydrophila, monovalen S. agalactiae, dan bivalen A. hydrophila + S. agalactiae (Sel utuh, produk ektraselular/ECP, crude supernatan, campuran sel utuh + ECP, dan broth. Uji tantang dilakukan menggunakan dosis LD50 infeksi tunggal maupun ko-infeksi dari bakteri A. hydrophila dan S. agalactiae. Efektivitas dan keampuhan vaksin tersebut dihitung berdasarkan nilai RPS (Relative Percent Survival dan hasil respon hematologi. Titer antibodi dapat terdeteksi setelah satu minggu pemeliharaan pasca vaksinasi. Nilai titer antar perlakuan vaksin bivalen berbeda nyata (P<0.05 dengan vaksin monovalen dan kontrol. Nilai RPS vaksin bivalen (campuran sel utuh + ECP mencapai 100 untuk uji tantang dengan A. hydrophila dan 56,7 pada uji tantang ko-infeksi. Vaksin monovalen A. hydrophila maupun S. agalactiae hanya mampu memproteksi terhadap bakteri homolog, tidak terjadi proteksi silang di antara keduanya.

Our Polar Past

Science.gov (United States)

Clary, Renee; Wandersee, James

2009-01-01

The study of polar exploration is fascinating and offers students insights into the history, culture, and politics that affect the developing sciences at the farthest ends of Earth. Therefore, the authors think there is value in incorporating polar exploration accounts within modern science classrooms, and so they conducted research to test their…

Marine polar steroids

International Nuclear Information System (INIS)

Stonik, Valentin A

2001-01-01

Structures, taxonomic distribution and biological activities of polar steroids isolated from various marine organisms over the last 8-10 years are considered. The peculiarities of steroid biogenesis in the marine biota and their possible biological functions are discussed. Syntheses of some highly active marine polar steroids are described. The bibliography includes 254 references.

Carbon nanotube fiber terahertz polarizer

Energy Technology Data Exchange (ETDEWEB)

Zubair, Ahmed [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Tsentalovich, Dmitri E.; Young, Colin C. [Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005 (United States); Heimbeck, Martin S. [Charles M. Bowden Laboratory, Aviation & Missile Research, Development, and Engineering Center (AMRDEC), Redstone Arsenal, Alabama 35898 (United States); Everitt, Henry O. [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Charles M. Bowden Laboratory, Aviation & Missile Research, Development, and Engineering Center (AMRDEC), Redstone Arsenal, Alabama 35898 (United States); Pasquali, Matteo [Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005 (United States); Department of Chemistry, Rice University, Houston, Texas 77005 (United States); Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Kono, Junichiro, E-mail: kono@rice.edu [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Department of Physics and Astronomy, Rice University, Houston, Texas 77005 (United States)

2016-04-04

Conventional, commercially available terahertz (THz) polarizers are made of uniformly and precisely spaced metallic wires. They are fragile and expensive, with performance characteristics highly reliant on wire diameters and spacings. Here, we report a simple and highly error-tolerant method for fabricating a freestanding THz polarizer with nearly ideal performance, reliant on the intrinsically one-dimensional character of conduction electrons in well-aligned carbon nanotubes (CNTs). The polarizer was constructed on a mechanical frame over which we manually wound acid-doped CNT fibers with ultrahigh electrical conductivity. We demonstrated that the polarizer has an extinction ratio of ∼−30 dB with a low insertion loss (<0.5 dB) throughout a frequency range of 0.2–1.1 THz. In addition, we used a THz ellipsometer to measure the Müller matrix of the CNT-fiber polarizer and found comparable attenuation to a commercial metallic wire-grid polarizer. Furthermore, based on the classical theory of light transmission through an array of metallic wires, we demonstrated the most striking difference between the CNT-fiber and metallic wire-grid polarizers: the latter fails to work in the zero-spacing limit, where it acts as a simple mirror, while the former continues to work as an excellent polarizer even in that limit due to the one-dimensional conductivity of individual CNTs.

Polarized radio outbursts in BL Lacertae. I. Polarized emission from a compact jet. II. The flux and polarization of a piston-driven shock

International Nuclear Information System (INIS)

Aller, H.D.; Aller, M.F.; Hughes, P.A.

1985-01-01

A second highly polarized burst in BL Lacertae observed in 1983 which has very similar properties to the earlier burst in 1981-82 is described, and it is shown that in both bursts the electric vector of the polarized emission is nearly parallel to the observed extended structure. A weak shock, moving relativistically close to the line of sight, appears to be a very effective means of producing the observed behavior. A simple model is developed to represent the outbursts as due to a piston-driven shock which exhibits polarized emission due to compression of the otherwise random magnetic field of a collimated flow. It is shown that the general features of total flux, polarized flux, and polarization position angle as a function of frequency and time can be understood in terms of such a model. 34 references

Circular polarization analyzer with polarization tunable focusing of surface plasmon polaritons

Energy Technology Data Exchange (ETDEWEB)

Wang, Sen; Zhang, Yan, E-mail: yzhang@mail.cnu.edu.cn [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Beijing Key Laboratory for Metamaterials and Devices, and Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University, Beijing 100048 (China); Wang, Xinke [Beijing Key Laboratory for Metamaterials and Devices, and Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University, Beijing 100048 (China); Kan, Qiang [State Key Laboratory for Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Qu, Shiliang [Optoelectronics Department, Harbin Institute of Technology at Weihai, Weihai 264209 (China)

2015-12-14

A practical circular polarization analyzer (CPA) that can selectively focus surface plasmon polaritons (SPPs) at two separate locations, according to the helicity of the circularly polarized light, is designed and experimentally verified in the terahertz frequency range. The CPA consists of fishbone-slit units and is designed using the simulated annealing algorithm. By differentially detecting the intensities of the two SPPs focuses, the helicity of the incident circularly polarized light can be obtained and the CPA is less vulnerable to the noise of incident light. The proposed device may also have wide potential applications in chiral SPPs photonics and the analysis of chiral molecules in biology.

Optically Polarized Conduction-Band Electrons in Tungsten Observed by Spin-Polarized Photoemission

DEFF Research Database (Denmark)

Zürcher, P.; Meier, F.; Christensen, N. E.

1979-01-01

Along the (100) direction of tungsten, interband transitions induced by circularly polarized light of energy 1.5 eV......Along the (100) direction of tungsten, interband transitions induced by circularly polarized light of energy 1.5 eV...

Polarization and ellipticity of high-order harmonics from aligned molecules generated by linearly polarized intense laser pulses

International Nuclear Information System (INIS)

Le, Anh-Thu; Lin, C. D.; Lucchese, R. R.

2010-01-01

We present theoretical calculations for polarization and ellipticity of high-order harmonics from aligned N 2 , CO 2 , and O 2 molecules generated by linearly polarized lasers. Within the rescattering model, the two polarization amplitudes of the harmonics are determined by the photo-recombination amplitudes for photons emitted with polarization parallel or perpendicular to the direction of the same returning electron wave packet. Our results show clear species-dependent polarization states, in excellent agreement with experiments. We further note that the measured polarization ellipse of the harmonic furnishes the needed parameters for a 'complete' experiment in molecules.

Multiband Circular Polarizer Based on Fission Transmission of Linearly Polarized Wave for X-Band Applications

Directory of Open Access Journals (Sweden)

Farman Ali Mangi

2016-01-01

Full Text Available A multiband circular polarizer based on fission transmission of linearly polarized wave for x-band application is proposed, which is constructed of 2 × 2 metallic strips array. The linear-to-circular polarization conversion is obtained by decomposing the linearly incident x-polarized wave into two orthogonal vector components of equal amplitude and 90° phase difference between them. The innovative approach of “fission transmission of linear-to-circular polarized wave” is firstly introduced to obtain giant circular dichroism based on decomposition of orthogonal vector components through the structure. It means that the incident linearly polarized wave is converted into two orthogonal components through lower printed metallic strips layer and two transmitted waves impinge on the upper printed strips layer to convert into four orthogonal vector components at the end of structure. This projection and transmission sequence of orthogonal components sustain the chain transmission of electromagnetic wave and can achieve giant circular dichroism. Theoretical analysis and microwave experiments are presented to validate the performance of the structure. The measured results are in good agreement with simulation results. In addition, the proposed circular polarizer exhibits the optimal performance with respect to the normal incidence. The right handed circularly polarized wave is emitted ranging from 10.08 GHz to 10.53 GHz and 10.78 GHz to 11.12 GHz, while the left handed circular polarized wave is excited at 10.54 GHz–10.70 GHz and 11.13 GHz–11.14 GHz, respectively.

Measuring polarization dependent dispersion of non-polarizing beam splitter cubes with spectrally resolved white light interferometry

Science.gov (United States)

Csonti, K.; Hanyecz, V.; Mészáros, G.; Kovács, A. P.

2017-06-01

In this work we have measured the group-delay dispersion of an empty Michelson interferometer for s- and p-polarized light beams applying two different non-polarizing beam splitter cubes. The interference pattern appearing at the output of the interferometer was resolved with two different spectrometers. It was found that the group-delay dispersion of the empty interferometer depended on the polarization directions in case of both beam splitter cubes. The results were checked by inserting a glass plate in the sample arm of the interferometer and similar difference was obtained for the two polarization directions. These results show that to reach high precision, linearly polarized white light beam should be used and the residual dispersion of the empty interferometer should be measured at both polarization directions.

Polarized semi-inclusive deep-inelastic scattering on transversely and longitudinally polarized nucleons at HERMES

International Nuclear Information System (INIS)

Hommes, B.

2005-01-01

The HERMES experiment has measured double spin asymmetries in the cross section for deep-inelastic scattering of longitudinal polarized positrons off longitudinal polarized hydrogen and deuterium targets. From these asymmetries, based on inclusive and semi-inclusive measurements, polarized quark distributions were extracted as a function of x. Single-spin azimuthal asymmetries in semi-inclusive pion production were measured by the HERMES experiment for the first time, with a transversely polarized hydrogen target. Two different sine-dependencies were extracted which can be related to the quark transversity distribution h q 1 (x) and the Sivers function (Author)

Polarized X-Ray Emission from Magnetized Neutron Stars: Signature of Strong-Field Vacuum Polarization

Science.gov (United States)

Lai, Dong; Ho, Wynn C.

2003-08-01

In the atmospheric plasma of a strongly magnetized neutron star, vacuum polarization can induce a Mikheyev-Smirnov-Wolfenstein type resonance across which an x-ray photon may (depending on its energy) convert from one mode into the other, with significant changes in opacities and polarizations. We show that this vacuum resonance effect gives rise to a unique energy-dependent polarization signature in the surface emission from neutron stars. The detection of polarized x rays from neutron stars can provide a direct probe of strong-field quantum electrodynamics and constrain the neutron star magnetic field and geometry.

Optimization of incident EC wave polarization in real-time polarization scan experiments on LHD

International Nuclear Information System (INIS)

Tsujimura, Toru I.; Mizuno, Yoshinori; Makino, Ryohei

2016-01-01

Real-time polarization scan experiments were performed on the Large Helical Device (LHD) to search an optimal incident wave polarization for electron cyclotron resonance heating. The obtained optimal polarization state to maximize the power absorption to the LHD plasma is compared with the ray-tracing code that includes mode content analyses, which indicates that the calculated results are generally in good agreement with the experimental results. The analyses show that optimal coupling to plasma waves requires a fine adjustment for an incident wave polarization even for perpendicular injection due to the finite density profile and the magnetic shear at the peripheral region. (author)

Polarized x-ray emission from magnetized neutron stars: signature of strong-field vacuum polarization.

Science.gov (United States)

Lai, Dong; Ho, Wynn C G

2003-08-15

In the atmospheric plasma of a strongly magnetized neutron star, vacuum polarization can induce a Mikheyev-Smirnov-Wolfenstein type resonance across which an x-ray photon may (depending on its energy) convert from one mode into the other, with significant changes in opacities and polarizations. We show that this vacuum resonance effect gives rise to a unique energy-dependent polarization signature in the surface emission from neutron stars. The detection of polarized x rays from neutron stars can provide a direct probe of strong-field quantum electrodynamics and constrain the neutron star magnetic field and geometry.

Spin-polarized tunneling through a ferromagnetic insulator

NARCIS (Netherlands)

Kok, M.; Kok, M.; Beukers, J.N.; Brinkman, Alexander

2009-01-01

The polarization of the tunnel conductance of spin-selective ferromagnetic insulators is modeled, providing a generalized concept of polarization including both the effects of electrode and barrier polarization. The polarization model is extended to take additional non-spin-polarizing insulating

Constraining Polarized Foregrounds for EoR Experiments. II. Polarization Leakage Simulations in the Avoidance Scheme

Energy Technology Data Exchange (ETDEWEB)

Nunhokee, C. D.; Bernardi, G.; Foster, G.; Grobler, T. L. [Department of Physics and Electronics, Rhodes University, P.O. Box 94, Grahamstown, 6140 (South Africa); Kohn, S. A.; Aguirre, J. E.; Martinot, J. Z. E. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA (United States); Thyagarajan, N. [Arizona State University, School of Earth and Space Exploration, Tempe, AZ 85287 (United States); Dillon, J. S. [Berkeley Center for Cosmological Physics, Berkeley, CA 94720 (United States); Parsons, A. R., E-mail: cnunhokee@gmail.com [Dept. of Astronomy, University of California, Berkeley, CA 94720 (United States)

2017-10-10

A critical challenge in the observation of the redshifted 21 cm line is its separation from bright Galactic and extragalactic foregrounds. In particular, the instrumental leakage of polarized foregrounds, which undergo significant Faraday rotation as they propagate through the interstellar medium, may harmfully contaminate the 21 cm power spectrum. We develop a formalism to describe the leakage due to instrumental widefield effects in visibility-based power spectra measured with redundant arrays, extending the delay-spectrum approach presented in Parsons et al. We construct polarized sky models and propagate them through the instrument model to simulate realistic full-sky observations with the Precision Array to Probe the Epoch of Reionization. We find that the leakage due to a population of polarized point sources is expected to be higher than diffuse Galactic polarization at any k mode for a 30 m reference baseline. For the same reference baseline, a foreground-free window at k > 0.3 h Mpc{sup −1} can be defined in terms of leakage from diffuse Galactic polarization even under the most pessimistic assumptions. If measurements of polarized foreground power spectra or a model of polarized foregrounds are given, our method is able to predict the polarization leakage in actual 21 cm observations, potentially enabling its statistical subtraction from the measured 21 cm power spectrum.

Polarization-dependent optics using gauge-field metamaterials

International Nuclear Information System (INIS)

Liu, Fu; Xiao, Shiyi; Li, Jensen; Wang, Saisai; Hang, Zhi Hong

2015-01-01

We show that effective gauge field for photons with polarization-split dispersion surfaces, being realized using uniaxial metamaterials, can be used for polarization control with unique opportunities. The metamaterials with the proposed gauge field correspond to a special choice of eigenpolarizations on the Poincaré sphere as pseudo-spins, in contrary to those from either conventional birefringent crystals or optical active media. It gives rise to all-angle polarization control and a generic route to manipulate photon trajectories or polarizations in the pseudo-spin domain. As demonstrations, we show beam splitting (birefringent polarizer), all-angle polarization control, unidirectional polarization filter, and interferometer as various polarization control devices in the pseudo-spin domain. We expect that more polarization-dependent devices can be designed under the same framework

The Bochum Polarized Target

International Nuclear Information System (INIS)

Reicherz, G.; Goertz, S.; Harmsen, J.; Heckmann, J.; Meier, A.; Meyer, W.; Radtke, E.

2001-01-01

The Bochum 'Polarized Target' group develops the target material 6 LiD for the COMPASS experiment at CERN. Several different materials like alcohols, alcanes and ammonia are under investigation. Solid State Targets are polarized in magnetic fields higher than B=2.5T and at temperatures below T=1K. For the Dynamic Nuclear Polarization process, paramagnetic centers are induced chemically or by irradiation with ionizing beams. The radical density is a critical factor for optimization of polarization and relaxation times at adequate magnetic fields and temperatures. In a high sensitive EPR--apparatus, an evaporator and a dilution cryostat with a continuous wave NMR--system, the materials are investigated and optimized. To improve the polarization measurement, the Liverpool NMR-box is modified by exchanging the fixed capacitor for a varicap diode which not only makes the tuning very easy but also provides a continuously tuned circuit. The dependence of the signal area upon the circuit current is measured and it is shown that it follows a linear function

Polarized protons at RHIC

International Nuclear Information System (INIS)

Tannenbaum, M.J.

1990-12-01

The Physics case is presented for the use of polarized protons at RHIC for one or two months each year. This would provide a facility with polarizations of approx-gt 50% high luminosity ∼2.0 x 10 32 cm -2 s -1 , the possibility of both longitudinal and transverse polarization at the interaction regions, and frequent polarization reversal for control of systematic errors. The annual integrated luminosity for such running (∼10 6 sec per year) would be ∫ Ldt = 2 x 10 38 cm -2 -- roughly 20 times the total luminosity integrated in ∼ 10 years of operation of the CERN Collider (∼10 inverse picobarns, 10 37 cm -2 ). This facility would be unique in the ability to perform parity-violating measurements and polarization test of QCD. Also, the existence of p-p collisions in a new energy range would permit the study of ''classical'' reactions like the total cross section and elastic scattering, etc., and serve as a complement to measurements from p-bar p colliders. 11 refs

Measuring fluorescence polarization with a dichrometer.

Science.gov (United States)

Sutherland, John C

2017-09-01

A method for obtaining fluorescence polarization data from an instrument designed to measure circular and linear dichroism is compared with a previously reported approach. The new method places a polarizer between the sample and a detector mounted perpendicular to the direction of the incident beam and results in determination of the fluorescence polarization ratio, whereas the previous method does not use a polarizer and yields the fluorescence anisotropy. A similar analysis with the detector located axially with the excitation beam demonstrates that there is no frequency modulated signal due to fluorescence polarization in the absence of a polarizer. Copyright © 2017. Published by Elsevier Inc.

Microwave-gated dynamic nuclear polarization

DEFF Research Database (Denmark)

Bornet, Aurélien; Pinon, Arthur; Jhajharia, Aditya

2016-01-01

Dissolution dynamic nuclear polarization (D-DNP) has become a method of choice to enhance signals in nuclear magnetic resonance (NMR). Recently, we have proposed to combine cross-polarization (CP) with D-DNP to provide high polarization P((13)C) in short build-up times. In this paper, we show...

Polarization Effects at a Muon Collider

International Nuclear Information System (INIS)

Parsa, Z.

1998-01-01

For Muon Colliders, Polarization will be a useful tool if high polarization is achievable with little luminosity loss. Formulation and effects of beam polarization and luminosity including polarization effects in Higgs resonance studies are discussed for improving precision measurements and Higgs resonance ''discovery'' capability e.g. at the First Muon Collider (FMC)

Neutron polarization measurements using the pulsed-polarized proton and deuteron beams at TUNL

International Nuclear Information System (INIS)

Walter, R.L.

1981-01-01

Nanosecond wide pulses of polarized protons or deuterons at a repetition rate of 4 MHz are now routinely available for studying interactions involving outgoing neutrons. Up to 90 nA of protons and 200 nA of deuterons have been observed on target. The authors' first experiments involved the determination of the analyzing power A /SUB y/ (UJ) for a few (→p,n) and (→d,n) reactions using conventional neutron time-of-flight detection. A major program for observing polarization effects in neutron elastic scattering has been initiated. The source of polarized neutrons for this program is the 2 H(→d,n→) 3 He reaction which yields a neutron beam having 90% of the polarization of the incident deuterons

Ultra-thin, single-layer polarization rotator

Directory of Open Access Journals (Sweden)

T. V. Son

2016-08-01

Full Text Available We demonstrate light polarization control over a broad spectral range by a uniform layer of vanadium dioxide as it undergoes a phase transition from insulator to metal. Changes in refractive indices create unequal phase shifts on s- and p-polarization components of incident light, and rotation of linear polarization shows intensity modulation by a factor of 103 when transmitted through polarizers. This makes possible polarization rotation devices as thin as 50 nm that would be activated thermally, optically or electrically.

Eddy intrusion of hot plasma into the polar cap and formation of polar-cap arcs

International Nuclear Information System (INIS)

Chiu, Y.T.; Gorney, D.J.

1983-01-01

We present plasma and electric field data obtained by the S3-3 satellite over the polar caps. We demonstrate that: (1) plasma signatures in the polar cap arc formation region near 5000 km altitude show clear intrusions of plasma sheet (approx.keV) and magneto sheath (approx.100 eV) plasma into a background of low-energy polar cap plasma; (2) the combined plasma and electric field signatures (electron inverted-V, ion beam and delxE<0) are exactly the same as in the evening discrete arc. We interpret this equivalence of polar cap and evening discrete arc signatures as indication that their formation processes are identical. The spatial structures of polar cap electric fields and the associated plasma signatures are consistent with the hypothesis that plasma intrusion into the polar cap takes the form of multiple cellular eddies. This hypothesis provides a unifying view of arc formation and arc configurations

Heidelberg polarized alkali source

International Nuclear Information System (INIS)

Kraemer, D.; Steffens, E.; Jaensch, H.; Philipps Universitaet, Marburg, Germany)

1984-01-01

A new atomic beam type polarized alkali ion source has been installed at Heidelberg. In order to improve the beam polarization considerably optical pumping is applied in combination with an adiabatic medium field transition which results in beams in single hyperfine sublevels. The m state population is determined by laser-induced fluorescence spectroscopy. Highly polarized beams (P/sub s/ > 0.9, s = z, zz) with intensities of 30 to 130 μA can be extracted for Li + and Na + , respectively

Polarized epithermal neutron spectrometer at KENS

International Nuclear Information System (INIS)

Kohgi, M.

1983-01-01

A spectrometer employing a white, epithermal, polarized neutron beam is under construction at KENS. The neutron polarization is achieved by passage through a dynamically polarized proton filter (DPPF). The results of the test experiments show that the DPPF method is promising in obtaining polarized epithermal neutron beam. The basic design of the spectrometer is described

Dynamic nuclear spin polarization

Energy Technology Data Exchange (ETDEWEB)

Stuhrmann, H B [GKSS-Forschungszentrum Geesthacht GmbH (Germany)

1996-11-01

Polarized neutron scattering from dynamic polarized targets has been applied to various hydrogenous materials at different laboratories. In situ structures of macromolecular components have been determined by nuclear spin contrast variation with an unprecedented precision. The experiments of selective nuclear spin depolarisation not only opened a new dimension to structural studies but also revealed phenomena related to propagation of nuclear spin polarization and the interplay of nuclear polarisation with the electronic spin system. The observation of electron spin label dependent nuclear spin polarisation domains by NMR and polarized neutron scattering opens a way to generalize the method of nuclear spin contrast variation and most importantly it avoids precontrasting by specific deuteration. It also likely might tell us more about the mechanism of dynamic nuclear spin polarisation. (author) 4 figs., refs.

Observing the Cosmic Microwave Background Polarization with Variable-delay Polarization Modulators for the Cosmology Large Angular Scale Surveyor

Science.gov (United States)

Harrington, Kathleen; CLASS Collaboration

2018-01-01

The search for inflationary primordial gravitational waves and the optical depth to reionization, both through their imprint on the large angular scale correlations in the polarization of the cosmic microwave background (CMB), has created the need for high sensitivity measurements of polarization across large fractions of the sky at millimeter wavelengths. These measurements are subjected to instrumental and atmospheric 1/f noise, which has motivated the development of polarization modulators to facilitate the rejection of these large systematic effects.Variable-delay polarization modulators (VPMs) are used in the Cosmology Large Angular Scale Surveyor (CLASS) telescopes as the first element in the optical chain to rapidly modulate the incoming polarization. VPMs consist of a linearly polarizing wire grid in front of a moveable flat mirror; varying the distance between the grid and the mirror produces a changing phase shift between polarization states parallel and perpendicular to the grid which modulates Stokes U (linear polarization at 45°) and Stokes V (circular polarization). The reflective and scalable nature of the VPM enables its placement as the first optical element in a reflecting telescope. This simultaneously allows a lock-in style polarization measurement and the separation of sky polarization from any instrumental polarization farther along in the optical chain.The Q-Band CLASS VPM was the first VPM to begin observing the CMB full time in 2016. I will be presenting its design and characterization as well as demonstrating how modulating polarization significantly rejects atmospheric and instrumental long time scale noise.

Polar and low polar solvents media effect on dipole moments of some diazo Sudan dyes

Science.gov (United States)

Zakerhamidi, M. S.; Golghasemi Sorkhabi, Sh.; Shamkhali, A. N.

2014-06-01

Absorption and fluorescence spectra of three Sudan dyes (SudanIII, SudanIV and Sudan black B) were recorded in various solvents with different polarity in the range of 300-800 nm, at room temperature. The solvatochromic method was used to investigate dipole moments of these dyes in ground and excited states, in different media. The solvatochromic behavior of these substances and their solvent-solute interactions were analyzed via solvent polarity parameters. Obtained results express the effects of solvation on tautomerism and molecular configuration (geometry) of Sudan dyes in solvent media with different polarity. Furthermore, analyze of solvent-solute interactions and value of ground and excited states dipole moments suggests different forms of resonance structures for Sudan dyes in polar and low-polar solvents.

Polarized constituent quarks in NLO approximation

International Nuclear Information System (INIS)

Khorramian, Ali N.; Tehrani, S. Atashbar; Mirjalili, A.

2006-01-01

The valon representation provides a basis between hadrons and quarks, in terms of which the bound-state and scattering properties of hadrons can be united and described. We studied polarized valon distributions which have an important role in describing the spin dependence of parton distribution in leading and next-to-leading order approximation. Convolution integral in frame work of valon model as a useful tool, was used in polarized case. To obtain polarized parton distributions in a proton we need to polarized valon distribution in a proton and polarized parton distributions inside the valon. We employed Bernstein polynomial averages to get unknown parameters of polarized valon distributions by fitting to available experimental data

Coherent active polarization control without loss

Science.gov (United States)

Ye, Yuqian; Hay, Darrick; Shi, Zhimin

2017-11-01

We propose a lossless active polarization control mechanism utilizing an anisotropic dielectric medium with two coherent inputs. Using scattering matrix analysis, we derive analytically the required optical properties of the anisotropic medium that can behave as a switchable polarizing beam splitter. We also show that such a designed anisotropic medium can produce linearly polarized light at any azimuthal direction through coherent control of two inputs with a specific polarization state. Furthermore, we present a straightforward design-on-demand procedure of a subwavelength-thick metastructure that can possess the desired optical anisotropy at a flexible working wavelength. Our lossless coherent polarization control technique may lead to fast, broadband and integrated polarization control elements for applications in imaging, spectroscopy, and telecommunication.

Dynamic polarization of radioactive nuclei

International Nuclear Information System (INIS)

Kiselev, Yu.F.; Lyuboshits, V.L.; )

2001-01-01

Radioactive nuclei, embedded into a frozen polarized proton target, atr proposed to polarize by means of some dynamic polarization methods. Angular distributions of γ-quanta emitted ny 22 Na(3 + ) in the cascade β-γ-radiation are calculated. It is shown that this distribution does not depend on the spin temperature sing at the Boltzmann distribution of populations among the Zeeman magnetic substates, whereas the tensor polarization of quadrupole nuclei, placed in the electric field of the crystal, causes the considerable sing dependence. The new method promises wide opportunities for the magnetic structure investigations as well as for the study of spin-spin interaction dynamics of rare nuclei in dielectrics. Physical-technical advantages and disadvantages of the given method are discussed for the polarization of heavy nuclei in the on-line implantation mode [ru

Latest polarization and beam characterization results of the Orsay polarized electron source

International Nuclear Information System (INIS)

Arianer, J.; Cohen, S.; Essabaa, S.; Frascaria, R.; Zerhouni, O.

1995-01-01

The Orsay polarized electron source based on the chemi-ionization of aligned He(2 3 S 1 ) atoms and CO 2 molecules is briefly described. The latest results concerning electron polarization and beam emittance are presented. The present development status is also discussed. (K.A.)

Modeling diffusion coefficients in binary mixtures of polar and non-polar compounds

DEFF Research Database (Denmark)

Medvedev, Oleg; Shapiro, Alexander

2005-01-01

The theory of transport coefficients in liquids, developed previously, is tested on a description of the diffusion coefficients in binary polar/non-polar mixtures, by applying advanced thermodynamic models. Comparison to a large set of experimental data shows good performance of the model. Only f...

Characterization of polarized THP-1 macrophages and polarizing ability of LPS and food compounds.

Science.gov (United States)

Chanput, Wasaporn; Mes, Jurriaan J; Savelkoul, Huub F J; Wichers, Harry J

2013-02-01

Little is known about the polarizing potential of currently used human macrophage cell lines, while a better understanding phenomena can support the prediction of effects in vivo based on in vitro analysis. To test the polarization capability of PMA differentiated-THP-1 macrophages (M0), cells were stimulated with 20 ng ml(-1) IFNγ + 1 μg ml(-1) LPS and 20 ng ml(-1) IL-4, which are known to influence macrophage polarization in vivo and ex vivo into the M1 and M2 state, respectively. Apart from several well-known M1 and M2 markers, also new possible markers for M1 and M2 polarization were analysed in this study. The expression of M1 marker genes was up-regulated in IFNγ + LPS stimulated-M0 THP-1 macrophages. The IL-4 stimulated-M0 THP-1 macrophages expressed M2 cell membrane receptor genes. However, M2 chemokine and their receptor genes were only slightly up-regulated which might be due to the complexity of the secondary cell-cell interaction of the chemokine system. Lipopolysaccharides from E. coli (LPS) and food compounds [lentinan, vitamin D3 (vD3) and the combination of lentinan + vitamin D3 (Len + vD3)] were investigated for their polarizing ability on M0 THP-1 macrophages towards either the M1 or M2 state. LPS (700 ng ml(-1)) was able to skew M0 THP-1 macrophages towards the M1 direction since all analysed M1 marker genes were strongly expressed. Lentinan, vD3 and Len + vD3 did not induce expression of either M1 or M2 markers, indicating no polarizing ability of these compounds. Based on the expression of M1 and M2 marker genes we concluded that THP-1 macrophages could be successfully polarized into either the M1 or M2 state. Therefore, they can be used as a new macrophage polarizing model to estimate the polarizing/switching ability of test food compounds.

Radiochromic film and polarization effects

International Nuclear Information System (INIS)

Yu, P.K.N.; Cheung, T.; Butson, M.J.; Cancer Services, Wollongong, NSW; Inwood, D.

2004-01-01

Full text: A new high sensitivity radiochromic film has been tested for its polarization properties. Gafchromic HS film has been shown to produce a relatively small (less than 3%) variation in measured optical density measured at 660nm wavelength when the light source is fully linear polarized and the film is rotated through 360 deg angle. Similar variations are seen when the detector is linearly polarized. If both light source and detector is linearly polarised variations in measured optical density can reach 15% when the film is rotated through 360 deg angle. This seems to be due to a phase shift in polarised light caused by the radiochromic film resulting in the polarised light source becoming out of phase with the polarised detector. Gafchromic HS radiochromic film produces a minimal polarization response with varying angle of rotation however we recommend that a polarization test be performed on a densitometry system to establish the extent of its polarization properties before accuracy dosimetry is performed with radiochromic HS film. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

Tracking polar lows in CLM

Energy Technology Data Exchange (ETDEWEB)

Zahn, M.; Storch, H. von [Inst. for Coastal Research, GKSS Research Center, Geesthacht (Germany); Meteorological Inst., Univ. of Hamburg (Germany)

2008-08-15

Polar lows are severe cyclones in sub-polar oceans sized beyond the resolved scale of existing global reanalysis products. We used the NCEP/NCAR reanalyses data to drive a regional climate model (CLM) in order to reproduce finer resolved atmospheric fields over the North Atlantic over a two year period. In these fields we detected polar lows by means of a detection algorithm based on a spatial digital bandpass filter. CLM was run in two different ways, the conventional way and with additionally prescribing the analysed large scale situation. The resulting temporal and spatial distributions of polar lows between the different simulations are compared. A reasonable seasonal cycle and spatial distribution was found for all simulations. A lower number of polar lows in the spectral nudged simulation indicates a closer vicinity to reality. Higher temporal and spatial variability between the conventional simulations suggest a more random generation of polar lows. Frequency distributions of track-lengths reveal shorter tracks when nudging is applied. Maximum wind speeds reveal only minor, insignificant differences between all runs and are higher in conventional mode. (orig.)

Polarization-induced hole doping in N-polar III-nitride LED grown by metalorganic chemical vapor deposition

KAUST Repository

Yan, Long

2018-05-03

Polarization-induced doping has been shown to be effective for wide-bandgap III-nitrides. In this work, we demonstrated a significantly enhanced hole concentration via linearly grading an N-polar AlxGa1-xN (x = 0–0.3) layer grown by metal-organic chemical vapor deposition. The hole concentration increased by ∼17 times compared to that of N-polar p-GaN at 300 K. The fitting results of temperature-dependent hole concentration indicated that the holes in the graded p-AlGaN layer comprised both polarization-induced and thermally activated ones. By optimizing the growth conditions, the hole concentration was further increased to 9.0 × 1017 cm−3 in the graded AlGaN layer. The N-polar blue-violet light-emitting device with the graded p-AlGaN shows stronger electroluminescence than the one with the conventional p-GaN. The study indicates the potential of the polarization doping technique in high-performance N-polar light-emitting devices.

Polarization-induced hole doping in N-polar III-nitride LED grown by metalorganic chemical vapor deposition

KAUST Repository

Yan, Long; Zhang, Yuantao; Han, Xu; Deng, Gaoqiang; Li, Pengchong; Yu, Ye; Chen, Liang; Li, Xiaohang; Song, Junfeng

2018-01-01

Polarization-induced doping has been shown to be effective for wide-bandgap III-nitrides. In this work, we demonstrated a significantly enhanced hole concentration via linearly grading an N-polar AlxGa1-xN (x = 0–0.3) layer grown by metal-organic chemical vapor deposition. The hole concentration increased by ∼17 times compared to that of N-polar p-GaN at 300 K. The fitting results of temperature-dependent hole concentration indicated that the holes in the graded p-AlGaN layer comprised both polarization-induced and thermally activated ones. By optimizing the growth conditions, the hole concentration was further increased to 9.0 × 1017 cm−3 in the graded AlGaN layer. The N-polar blue-violet light-emitting device with the graded p-AlGaN shows stronger electroluminescence than the one with the conventional p-GaN. The study indicates the potential of the polarization doping technique in high-performance N-polar light-emitting devices.

Determining Polarities Of Distant Lightning Strokes

Science.gov (United States)

Blakeslee, Richard J.; Brook, Marx

1990-01-01

Method for determining polarities of lightning strokes more than 400 km away. Two features of signal from each stroke correlated. New method based on fact each stroke observed thus far for which polarity determined unambiguously, initial polarity of tail same as polarity of initial deflection before initial-deflection signal altered by propagation effects. Receiving station equipped with electric-field-change antenna coupled to charge amplifier having time constant of order of 1 to 10 seconds. Output of amplifier fed to signal-processing circuitry, which determines initial polarity of tail.

System of measurement of proton polarization in a polarized target

Energy Technology Data Exchange (ETDEWEB)

Karnaukov, I.M.; Chechetenko, V.F.; Lukhanin, A.A.; Telegin, Y.N.; Trotsenko, V.I.

1985-05-01

This paper describes a nuclear magnetic resonance spectrometer with high sensitivity. The signal of NMR absorption is recorded by a Q-meter with a series circuit and a circuit for compensation of the resonance characteristic of the measuring circuit. In order to ensure uniform sensitivity of the system to the state of polarization throughout the volume of the target and to enhance the S/N ration the measuring coil is made of a flat conductor. The polarization-measuring system works on-line with an M-6000 computer. The total error of measurement of the polarization of free protons in a target with allowance for the error due to local depolarization of free protons in a target with allowance for the error due to local depolarization of the working substance under irradiation with an intense photon beam is less than or equal to 6%.

Invited article: polarization "down under": the polarized time-of-flight neutron reflectometer PLATYPUS.

Science.gov (United States)

Saerbeck, T; Klose, F; Le Brun, A P; Füzi, J; Brule, A; Nelson, A; Holt, S A; James, M

2012-08-01

This review presents the implementation and full characterization of the polarization equipment of the time-of-flight neutron reflectometer PLATYPUS at the Australian Nuclear Science and Technology Organisation (ANSTO). The functionality and efficiency of individual components are evaluated and found to maintain a high neutron beam polarization with a maximum of 99.3% through polarizing Fe/Si supermirrors. Neutron spin-flippers with efficiencies of 99.7% give full control over the incident and scattered neutron spin direction over the whole wavelength spectrum available in the instrument. The first scientific experiments illustrate data correction mechanisms for finite polarizations and reveal an extraordinarily high reproducibility for measuring magnetic thin film samples. The setup is now fully commissioned and available for users through the neutron beam proposal system of the Bragg Institute at ANSTO.

Polarization effects in hadron fragmentation

International Nuclear Information System (INIS)

Lednicky, R.

1984-01-01

Hadron polarization (spin alignment) and polarization asymmetry are discussed in terms of the quark recombination model with the spin-orbit interaction taken into account. It is shown that predictions of this model are at least in qualitative agreement with experimental data. Various polarization mechanisms in terms of this model and the possibility of their checking are also discussed

FIRST POLARIZED PROTON COLLISIONS AT RHIC

International Nuclear Information System (INIS)

ROSER, T.; AHRENS, L.; ALESSI, J.; BAI, M.; BEEBE-WANG, J.; BRENNAN, J.M.; BROWN, K.A.; BUNCE, G.; CAMERON, P.; COURANT, E.D.; DREES, A.; FISCHER, W.; FLILLER, R. III; GLENN, W.; HUANG, H.; LUCCIO, A.U.; MACKAY, W.W.; MAKDISI, Y.; MONTAG, C.; PILAT, F.; PTITSYN, V.; SATOGATA, T.

2002-01-01

We successfully injected polarized protons in both RHIC rings and maintained polarization during acceleration up to 100 GeV per ring using two Siberian snakes in each ring. Each snake consists of four helical superconducting dipoles which rotate the polarization by 180 o about a horizontal axis. This is the first time that polarized protons have been accelerated to 100 GeV

Evaluation of Extraction Protocols for Simultaneous Polar and Non-Polar Yeast Metabolite Analysis Using Multivariate Projection Methods

Directory of Open Access Journals (Sweden)

Nicolas P. Tambellini

2013-07-01

Full Text Available Metabolomic and lipidomic approaches aim to measure metabolites or lipids in the cell. Metabolite extraction is a key step in obtaining useful and reliable data for successful metabolite studies. Significant efforts have been made to identify the optimal extraction protocol for various platforms and biological systems, for both polar and non-polar metabolites. Here we report an approach utilizing chemoinformatics for systematic comparison of protocols to extract both from a single sample of the model yeast organism Saccharomyces cerevisiae. Three chloroform/methanol/water partitioning based extraction protocols found in literature were evaluated for their effectiveness at reproducibly extracting both polar and non-polar metabolites. Fatty acid methyl esters and methoxyamine/trimethylsilyl derivatized aqueous compounds were analyzed by gas chromatography mass spectrometry to evaluate non-polar or polar metabolite analysis. The comparative breadth and amount of recovered metabolites was evaluated using multivariate projection methods. This approach identified an optimal protocol consisting of 64 identified polar metabolites from 105 ion hits and 12 fatty acids recovered, and will potentially attenuate the error and variation associated with combining metabolite profiles from different samples for untargeted analysis with both polar and non-polar analytes. It also confirmed the value of using multivariate projection methods to compare established extraction protocols.

Polarization Measurements in High-Energy Deuteron Photodisintegration

International Nuclear Information System (INIS)

Adam Sarty; Andrei Afanasev; Arunava Saha; Bogdan Wojtsekhowski; Brendan Fox; Chang, C.; Cathleen Jones; Charles Glashausser; Charles Perdrisat; Cornelis De Jager; Cornelis De Jager; Cornelis de Jager; Crovelli, D.; Daniel Simon; David Meekins; Demetrius Margaziotis; Dipangkar Dutta; Edgar Kooijman; Edward Brash; Edward Kinney; Elaine Schulte; Eugene Chudakov; Feng Xiong; Franco Garibaldi; Garth Huber; Gerfried Kumbartzki; Guido Urciuoli; Haiyan Gao; James Kelly; Javier Gomez; Jens-Ole Hansen; Jian-Ping Chen; John Calarco; John LeRose; Jordan Hovdebo; Joseph Mitchell; Juncai Gao; Kamal Benslama; Kathy McCormick; Kevin Fissum; Konrad Aniol; Krishni Wijesooriya; Louis Bimbot; Ludyvine Morand; Luminita Todor; Marat Rvachev; Mark Jones; Martin Epstein; Meihua Liang; Michael Kuss; Moskov Amarian; Nilanga Liyanage; Oleksandr Glamazdin; Olivier Gayou; Paul Ulmer; Pete Markowitz; Peter Bosted; Holt, R.; Riad Suleiman; Richard Lindgren; Rikki Roche; Robert Michaels; Roman Pomatsalyuk; Ronald Gilman; Ronald Ransome; Salvatore Frullani; Scott Dumalski; Seonho Choi; Sergey Malov; Sonja Dieterich; Steffen Strauch; Stephen Becher; Steve Churchwell; Ting Chang; Viktor Gorbenko; Vina Punjabi; Xiaodong Jiang; Zein-Eddine Meziani; Zhengwei Chai; Wang Xu

2001-01-01

We present measurements of the recoil proton polarization for the d(polarized y, polarized p)n reaction at thetac.m. = 90 degrees for photon energies up to 2.4 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. The induced polarization py vanishes above 1 GeV, contrary to meson-baryon model expectations, in which resonances lead to large polarizations. However, the polarization transfer Cx does not vanish above 1 GeV, inconsistent with hadron helicity conservation. Thus, we show that the scaling behavior observed in the d(y,p)n cross sections is not a result of perturbative QCD. These data should provide important tests of new nonperturbative calculations in the intermediate energy regime

Polarization at LEP: Status and prospects

International Nuclear Information System (INIS)

Koutchouk, J.P.

1993-01-01

The first evidence of a measurable signal of transverse polarization was observed at the end of 1990. In 1991, polarized beams were repeatedly obtained with average and peak polarization levels of 10 and 19% and used to calibrate the beam energy by resonant depolarization. Simulation studies show that the polarization level can be increased above the 50% by harmonic spin matching. This is sufficient to open the possibility of doing physics with longitudinally polarized beams. A spin rotator has been designed for LEP. The feasibility study of operating LEP in this mode concludes at the possibility of providing polarized beams at a good performance level, if the high photon background can be reduced to a tolerable level. (author). 10 refs, 3 figs, 5 tabs

Coherent active polarization control without loss

Directory of Open Access Journals (Sweden)

Yuqian Ye

2017-11-01

Full Text Available We propose a lossless active polarization control mechanism utilizing an anisotropic dielectric medium with two coherent inputs. Using scattering matrix analysis, we derive analytically the required optical properties of the anisotropic medium that can behave as a switchable polarizing beam splitter. We also show that such a designed anisotropic medium can produce linearly polarized light at any azimuthal direction through coherent control of two inputs with a specific polarization state. Furthermore, we present a straightforward design-on-demand procedure of a subwavelength-thick metastructure that can possess the desired optical anisotropy at a flexible working wavelength. Our lossless coherent polarization control technique may lead to fast, broadband and integrated polarization control elements for applications in imaging, spectroscopy, and telecommunication.

Polarized Light Corridor Demonstrations.

Science.gov (United States)

Davies, G. R.

1990-01-01

Eleven demonstrations of light polarization are presented. Each includes a brief description of the apparatus and the effect demonstrated. Illustrated are strain patterns, reflection, scattering, the Faraday Effect, interference, double refraction, the polarizing microscope, and optical activity. (CW)

Draft genome sequences of three Aeromonas hybrophila isolates from catfish and tilapia

Science.gov (United States)

Aeromonas hydrophila is a Gram-negative bacteria that is particularly adapted to freshwater environments and can cause severe infections in fish and humans. Here we report the draft genomes of three A. hydrophila catfish and tilapia isolates....

Geomagnetic polarity epochs: age and duration of the olduvai normal polarity event

Science.gov (United States)

Gromme, C.S.; Hay, R.L.

1971-01-01

New data show that the Olduvai normal geomagnetic polarity event is represented in Olduvai Gorge, Tanzania, by rocks covering a time span of roughly from 0.1 to 0.2 my and is no older than 2.0 my. Hence the long normal polarity event of this age that is seen in deep-sea sediment cores and in magnetic profiles over oceanic ridges should be called the Olduvai event. The lava from which the Gilsa?? event was defined may have been erupted during the Olduvai event and, if so, the term Gilsa?? should now be abandoned. Many dated lavas that were originally assigned to the Olduvai event represent one or two much shorter normal polarity events that preceded the Olduvai event; these are herein named the Re??union normal polarity events. This revision brings the geomagnetic reversal time scale into conformity with the one implied by assumptions of uniform sedimentation rates on the ocean floor and uniform rates of sea-floor spreading. ?? 1971.

Production of spin-polarized unstable nuclei by using polarized electron capture process

International Nuclear Information System (INIS)

Shimizu, S.

1998-01-01

Measurements of emitted radiation from spin polarized nuclei are used to get information on electromagnetic moment of ground state unstable nuclei together with spin or parity state of excited states of their decayed (daughter) nuclei. These data are known to be useful for experimental investigation into the structure of unstable nuclei far from the stability line. The present study aims to establish a general method applicable to 11 Be and 16 N nuclei. To produce spin polarization, a new method in which the electron spin polarization of Rb is firstly produced by laser pumping, then the electron is transferred to the unstable nuclear beam (RNB) when they passes through the Rb vapor is proposed. Finally the polarized RNB will be implanted into superfluid helium to remain with a long spin-relaxation time. Future experimental set up for the above measurement adopted in the available radioactive nuclear beam facilities is briefly described. (Ohno, S.)

$\\Lambda$ and $\\bar{\\Lambda}$ polarization at COMPASS

CERN Document Server

Kang, Donghee

2010-01-01

At the COMPASS experiment $\\Lambda$ and $\\bar{\\Lambda}$ particles are produced with high statistics in deep inelastic scattering (DIS) processes of 160 GeV/c polarized muons. Since both, beam and target, are polarized, various studies on the $\\Lambda$ polarization are possible. We present results on the longitudinal polarization transfer from muons to $\\Lambda$ hyperons produced by scattering off an unpolarized isoscalar target and preliminary results on the transverse $\\Lambda$ polarization with a transversely polarized proton target. The $\\Lambda$ and $\\bar{\\Lambda}$ polarization can be studied by measuring the acceptance corrected angular distribution of its decay products. The longitudinal spin transfers to $\\Lambda$ and $\\bar{\\Lambda}$ produced in the current fragmentation region exhibit different behaviours as a function of $x_{Bj}$ and $x_{F}$. The $x_{Bj}$ and $x_{F}$ dependences of $\\Lambda$ polarization are compatible with zero, while $\\bar{\\Lambda}$ polarization tends to increase with $x_{F}$. Info...

A polarity-induced defect mechanism for conductivity and magnetism at polar-nonpolar oxide interfaces.

Science.gov (United States)

Yu, Liping; Zunger, Alex

2014-10-13

The discovery of conductivity and magnetism at the polar-nonpolar interfaces of insulating nonmagnetic oxides such as LaAlO3 and SrTiO3 has raised prospects for attaining interfacial functionalities absent in the component materials. Yet, the microscopic origin of such emergent phenomena remains unclear, posing obstacles to design of improved functionalities. Here we present first principles calculations of electronic and defect properties of LaAlO3/SrTiO3 interfaces and reveal a unifying mechanism for the origins of both conductivity and magnetism. We demonstrate that the polar discontinuity across the interface triggers thermodynamically the spontaneous formation of certain defects that in turn cancel the polar field induced by the polar discontinuity. The ionization of the spontaneously formed surface oxygen vacancy defects leads to interface conductivity, whereas the unionized Ti-on-Al antisite defects lead to interface magnetism. The proposed mechanism suggests practical design principles for inducing and controlling both conductivity and magnetism at general polar-nonpolar interfaces.

Polarization variablity among Wolf-Rayet stars. IV. A complete lack of circular polarization in the optical continuum

International Nuclear Information System (INIS)

Robert, C.; Moffat, A.F.J.

1989-01-01

Quasi-simultaneous blue and red, broadband optical monitoring in linear and circular polarization and in intensity has been carried out over an interval of three weeks for several Wolf-Rayet stars that show relatively large Delta P variations in linear polarization. No significant varying Delta V component of circular polarization is detected in any of these stars. The lower upper limit Delta V/Delta P implies that the intrinsic linearly polarized light which does vary cannot be produced by electrons gyrating in a magnetic field, unless they are ultrarelativistic - a rather unlikely situation. The low mean circular polarization typically observed is probably interstellar in origin. Lack of periodicity in the observed variations of linear polarization implies that even weak magnetic field loops are unlikely to be involved in confining pockets of wind plasma. The observed linear polarization variations are related mainly to electron scattering. 25 refs

Optical neutron polarizers

International Nuclear Information System (INIS)

Hayter, J.B.

1990-01-01

A neutron wave will be refracted by an appropriately varying potential. Optical neutron polarizers use spatially varying, spin- dependent potentials to refract neutrons of opposite spin states into different directions, so that an unpolarized beam will be split into two beams of complementary polarization by such a device. This paper will concentrate on two methods of producing spin-dependent potentials which are particularly well-suited to polarizing cold neutron beams, namely thin-film structures and field-gradient techniques. Thin-film optical devices, such as supermirror multilayer structures, are usually designed to deviate only one spin-state, so that they offer the possibility of making insertion (transmission) polarizers. Very good supermirrors may now be designed and fabricated, but it is not always straightforward to design mirror-based devices which are useful in real (divergent beam) applications, and some practical configurations will be discussed. Field-gradient devices, which are usually based on multipolar magnets, have tended to be too expensive for general use, but this may change with new developments in superconductivity. Dipolar and hexapolar configurations will be considered, with emphasis on the focusing characteristics of the latter. 21 refs., 7 figs

Polarizer reflectivity variations

International Nuclear Information System (INIS)

Ozarski, R.G.; Prior, J.

1980-01-01

On Shiva the beam energy along the chain is monitored using available reflections and/or transmission through beam steering, splitting, and polarizing optics without the intrusion of any additional glass for diagnostics. On the preamp table the diagnostic signal is obtained from the signal transmitted through turning mirrors. At the input of each chain the signal is obtained from the transmission through one of the mirrors used for the chain input alignment sensor (CHIP). At the chain output the transmission through the final turning mirror is used. These diagnostics have proved stable and reliable. However, one of the prime diagnostic locations is at the output of the beta rod. The energy at this location is measured by collecting small reflections from the last polarizer surface of the beta Pockels cell polarizer package. Unfortunately, calibration of this diagnostic has varied randomly, seldom remaining stable for a week or more. The cause of this fluctuation has been investigated for the past year and'it has been discovered that polarizer reflectivity varies with humidity. This report will deal with the possible causes that were investigated, the evidence that humidity is causing the variation, and the associated mechanism

RETRIEVAL OF AEROSOL PHASE FUNCTION AND POLARIZED PHASE FUNCTION FROM POLARIZATION OF SKYLIGHT FOR DIFFERENT OBSERVATION GEOMETRIES

Directory of Open Access Journals (Sweden)

L. Li

2018-04-01

Full Text Available The phase function and polarized phase function are important optical parameters, which describe scattering properties of atmospheric aerosol particles. Polarization of skylight induced by the scattering processes is sensitive to the scattering properties of aerosols. The Stokes parameters I, Q, U and the polarized radiance Lp of skylight measured by the CIMEL dual-polar sun-sky radiometer CE318- DP can be use to retrieve the phase function and polarized phase function, respectively. Two different observation geometries (i.e., the principal plane and almucantar are preformed by the CE318-DP to detect skylight polarization. Polarization of skylight depends on the illumination and observation geometries. For the same solar zenith angle, retrievals of the phase function and the polarized phase function are still affected by the observation geometry. The performance of the retrieval algorithm for the principal plane and almucantar observation geometries was assessed by the numerical experiments at two typical high and low sun’s positions (i.e. solar zenith angles are equal to 45° and 65°. Comparing the results for the principal plane and almucantar geometries, it is recommended to utilize the principal plane observations to retrieve the phase function when the solar zenith angle is small. The Stokes parameter U and the polarized radiance Lp from the almucantar observations are suggested to retrieve the polarized phase function, especially for short wavelength channels (e.g., 440 and 500 nm.

Retrieval of Aerosol Phase Function and Polarized Phase Function from Polarization of Skylight for Different Observation Geometries

Science.gov (United States)

Li, L.; Qie, L. L.; Xu, H.; Li, Z. Q.

2018-04-01

The phase function and polarized phase function are important optical parameters, which describe scattering properties of atmospheric aerosol particles. Polarization of skylight induced by the scattering processes is sensitive to the scattering properties of aerosols. The Stokes parameters I, Q, U and the polarized radiance Lp of skylight measured by the CIMEL dual-polar sun-sky radiometer CE318- DP can be use to retrieve the phase function and polarized phase function, respectively. Two different observation geometries (i.e., the principal plane and almucantar) are preformed by the CE318-DP to detect skylight polarization. Polarization of skylight depends on the illumination and observation geometries. For the same solar zenith angle, retrievals of the phase function and the polarized phase function are still affected by the observation geometry. The performance of the retrieval algorithm for the principal plane and almucantar observation geometries was assessed by the numerical experiments at two typical high and low sun's positions (i.e. solar zenith angles are equal to 45° and 65°). Comparing the results for the principal plane and almucantar geometries, it is recommended to utilize the principal plane observations to retrieve the phase function when the solar zenith angle is small. The Stokes parameter U and the polarized radiance Lp from the almucantar observations are suggested to retrieve the polarized phase function, especially for short wavelength channels (e.g., 440 and 500 nm).

A polarized alkali ion source

International Nuclear Information System (INIS)

Boettger, R.; Tungate, G.; Bauer, B.; Egelhof, P.; Moebius, K.H.; Steffens, E.

1978-01-01

The beam foil technique has been applied to detect nuclear vector polarization of a 10 keV 23 Na + beam. The result was about 70% of the atomic beam polarization thus limiting the depolarization by the surface ionizer to at most 30%. In a Coulomb excitation experiment with a tensor polarized 42 MeV 23 Na 7+ beam an effect of 0.011 +- 0.003 was measured yielding a value of t 20 approx. 0.04 for the beam polarization. The depolarization during the acceleration process can be estimated to be about 0.8. (orig.) [de

The new polarizer devices at RESEDA

International Nuclear Information System (INIS)

Repper, J; Häußler, W; Ostermann, A; Kredler, L; Chacón, A; Böni, P

2012-01-01

In the neutron resonance spin echo method the information about sample dynamics is encoded in the neutron beam polarization measured in the analyzer-detector unit. Thus, the method is not applicable for sample systems and environments, which depolarize the neutron beam strongly. To over come this draw back a neutron analyzer directly before the sample position may be installed to perform MIEZE-I experiments. We compared the performance of a transmission polarizer and a solid-state bender at this position for the neutron resonance spin echo spectrometer RESEDA by Monte Carlo simulations. It turned out, that the polarization as well as the intensity transmitted to the sample position is more advantageous for the transmission polarizer as for the bender. In addition, we present measurements of the polarization and intensity performance of the transmission polarizer already installed at RESEDA to polarize the neutron beam coming from the reactor FRM II. The measurements are in good agreement with Monte Carlo simulations.

Detailed analysis of evolution of the state of polarization in all-fiber polarization transformers.

Science.gov (United States)

Zhu, Xiushan; Jain, Ravinder K

2006-10-30

We present a detailed analysis of key attributes and performance characteristics of controllably-spun birefringent-fiber-based all-fiber waveplates or "all fiber polarization transformers" (AFPTs), first proposed and demonstrated by Huang [11]; these AFPTs consist essentially of a long carefully-designed "spin-twisted" high-birefringence fiber, fabricated by slowly varying the spin rate of a birefringent fiber preform (either from very fast to very slow or vice versa) while the fiber is being drawn. The evolution of the eigenstate from a linear polarization state to a circular polarization state, induced by slow variation of the intrinsic structure from linear anisotropy at the unspun end to circular anisotropy at the fast-spun end, enables the AFPT to behave like an all-fiber quarter-wave plate independent of the wavelength of operation. Power coupling between local eigenstates causes unique evolution of the polarization state along the fiber, and has been studied to gain insight into - as well as to understand detailed characteristics of -- the polarization transformation behavior. This has been graphically illustrated via plots of the relative power in these local eigenstates as a function of distance along the length of the fiber and plots of the extinction ratio of the output state of polarization (SOP) as a function of distance and the normalized spin rate. Deeper understanding of such polarization transformers has been further elucidated by quantitative calculations related to two crucial requirements for fabricating practical AFPT devices. Our calculations have also indicated that the polarization mode dispersion behaviour of the AFPT is much smaller than that of the original birefringent fiber. Finally, a specific AFPT was experimentally investigated at two widely-separated wavelengths (1310 nm and 1550 nm) of interest in telecommunications systems applications, further demonstrating and elucidating the broadband character of such AFPTs.

GUIDE FOR POLARIZED NEUTRONS

Science.gov (United States)

Sailor, V.L.; Aichroth, R.W.

1962-12-01

The plane of polarization of a beam of polarized neutrons is changed by this invention, and the plane can be flipped back and forth quicitly in two directions in a trouble-free manner. The invention comprises a guide having a plurality of oppositely directed magnets forming a gap for the neutron beam and the gaps are spaced longitudinally in a spiral along the beam at small stepped angles. When it is desired to flip the plane of polarization the magnets are suitably rotated to change the direction of the spiral of the gaps. (AEC)

Generalized Expression for Polarization Density

International Nuclear Information System (INIS)

Wang, Lu; Hahm, T.S.

2009-01-01

A general polarization density which consists of classical and neoclassical parts is systematically derived via modern gyrokinetics and bounce-kinetics by employing a phase-space Lagrangian Lie-transform perturbation method. The origins of polarization density are further elucidated. Extending the work on neoclassical polarization for long wavelength compared to ion banana width [M. N. Rosenbluth and F. L. Hinton, Phys. Rev. Lett. 80, 724 (1998)], an analytical formula for the generalized neoclassical polarization including both finite-banana-width (FBW) and finite-Larmor-radius (FLR) effects for arbitrary radial wavelength in comparison to banana width and gyroradius is derived. In additional to the contribution from trapped particles, the contribution of passing particles to the neoclassical polarization is also explicitly calculated. Our analytic expression agrees very well with the previous numerical results for a wide range of radial wavelength.

DISCOVERY OF POLARIZATION REVERBERATION IN NGC 4151

Energy Technology Data Exchange (ETDEWEB)

Gaskell, C. Martin; Shoji, Masatoshi [Department of Physics and Astronomy, University of Nebraska, Lincoln, NE 68588-0111 (United States); Goosmann, Rene W. [Observatoire astronomique de Strasbourg, 11 rue de l' Universite, F-67000 Strasbourg (France); Merkulova, Nelly I.; Shakhovskoy, Nikolay M., E-mail: martin.gaskell@uv.cl, E-mail: mshoji@astro.as.utexas.edu, E-mail: rene.goosmann@astro.unistra.fr [Crimean Astrophysical Observatory, Nauchny, Crimea 98409 (Ukraine)

2012-04-20

Observations of the optical polarization of NGC 4151 in 1997-2003 show variations of an order of magnitude in the polarized flux while the polarization position angle remains constant. The amplitude of variability of the polarized flux is comparable to the amplitude of variability of the total U-band flux, except that the polarized flux follows the total flux with a lag of 8 {+-} 3 days. The time lag and the constancy of the position angle strongly favor a scattering origin for the variable polarization rather than a non-thermal synchrotron origin. The orientation of the position angle of the polarized flux (parallel to the radio axis) and the size of the lag imply that the polarization arises from electron scattering in a flattened region within the low-ionization component of the broad-line region. Polarization from dust scattering in the equatorial torus is ruled out as the source of the lag in polarized flux because it would produce a larger lag and, unless the half-opening angle of the torus is >53 Degree-Sign , the polarization would be perpendicular to the radio axis. We note a long-term change in the percentage of polarization at similar total flux levels, and this could be due either to changing non-axisymmetry in the optical continuum emission or a change in the number of scatterers on a timescale of years.

A method to calculate Stokes parameters and angle of polarization of skylight from polarized CIMEL sun/sky radiometers

International Nuclear Information System (INIS)

Li, L.; Li, Z.; Li, K.; Blarel, L.; Wendisch, M.

2014-01-01

The polarized CIMEL sun/sky radiometers have been routinely operated within the Sun/sky-radiometer Observation NETwork (SONET) in China and some sites of the AErosol RObotic NETwork (AERONET) around the world. However, the polarization measurements are not yet widely used due to in a certain degree the lack of Stokes parameters derived directly from these polarization measurements. Meanwhile, it have been shown that retrievals of several microphysical properties of aerosol particles can be significantly improved by using degree of linear polarization (DoLP) measurements of polarized CIMEL sun/sky radiometers (CE318-DP). The Stokes parameters Q and U, as well as angle of polarization (AoP) contain additional information about linear polarization and its orientation. A method to calculate Stokes parameters Q, U, and AoP from CE318-DP polarized skylight measurements is introduced in this study. A new polarized almucantar geometry based on CE318-DP is measured to illustrate abundant variation features of these parameters. The polarization parameters calculated in this study are consistent with previous results of DoLP and I, and also comparable to vector radiative transfer simulations. - Highlights: • The CE318-DP polarized measurements are not yet widely used except DoLP. • Compared with DoLP and I, difficulty in calculating Stokes Q and U is discussed. • A new polarized almucantar observation geometry based on CE318-DP is executed. • We derive Stokes Q, U, and AoP both in principal and almucantar plane geometries. • The results are comparable with previous DoLP and I, as well as model simulations

Self-adaptive demodulation for polarization extinction ratio in distributed polarization coupling.

Science.gov (United States)

Zhang, Hongxia; Ren, Yaguang; Liu, Tiegen; Jia, Dagong; Zhang, Yimo

2013-06-20

A self-adaptive method for distributed polarization extinction ratio (PER) demodulation is demonstrated. It is characterized by dynamic PER threshold coupling intensity (TCI) and nonuniform PER iteration step length (ISL). Based on the preset PER calculation accuracy and original distribution coupling intensity, TCI and ISL can be made self-adaptive to determine contributing coupling points inside the polarizing devices. Distributed PER is calculated by accumulating those coupling points automatically and selectively. Two different kinds of polarization-maintaining fibers are tested, and PERs are obtained after merely 3-5 iterations using the proposed method. Comparison experiments with Thorlabs commercial instrument are also conducted, and results show high consistency. In addition, the optimum preset PER calculation accuracy of 0.05 dB is obtained through many repeated experiments.

Asymptotic theory of circular polarization memory.

Science.gov (United States)

Dark, Julia P; Kim, Arnold D

2017-09-01

We establish a quantitative theory of circular polarization memory, which is the unexpected persistence of the incident circular polarization state in a strongly scattering medium. Using an asymptotic analysis of the three-dimensional vector radiative transfer equation (VRTE) in the limit of strong scattering, we find that circular polarization memory must occur in a boundary layer near the portion of the boundary on which polarized light is incident. The boundary layer solution satisfies a one-dimensional conservative scattering VRTE. Through a spectral analysis of this boundary layer problem, we introduce the dominant mode, which is the slowest-decaying mode in the boundary layer. To observe circular polarization memory for a particular set of optical parameters, we find that this dominant mode must pass three tests: (1) this dominant mode is given by the largest, discrete eigenvalue of a reduced problem that corresponds to Fourier mode k=0 in the azimuthal angle, and depends only on Stokes parameters U and V; (2) the polarization state of this dominant mode is largely circular polarized so that |V|≫|U|; and (3) the circular polarization of this dominant mode is maintained for all directions so that V is sign-definite. By applying these three tests to numerical calculations for monodisperse distributions of Mie scatterers, we determine the values of the size and relative refractive index when circular polarization memory occurs. In addition, we identify a reduced, scalar-like problem that provides an accurate approximation for the dominant mode when circular polarization memory occurs.

Advancing Environmental Prediction Capabilities for the Polar Regions and Beyond during The Year of Polar Prediction

Science.gov (United States)

Werner, Kirstin; Goessling, Helge; Hoke, Winfried; Kirchhoff, Katharina; Jung, Thomas

2017-04-01

Environmental changes in polar regions open up new opportunities for economic and societal operations such as vessel traffic related to scientific, fishery and tourism activities, and in the case of the Arctic also enhanced resource development. The availability of current and accurate weather and environmental information and forecasts will therefore play an increasingly important role in aiding risk reduction and safety management around the poles. The Year of Polar Prediction (YOPP) has been established by the World Meteorological Organization's World Weather Research Programme as the key activity of the ten-year Polar Prediction Project (PPP; see more on www.polarprediction.net). YOPP is an internationally coordinated initiative to significantly advance our environmental prediction capabilities for the polar regions and beyond, supporting improved weather and climate services. Scheduled to take place from mid-2017 to mid-2019, the YOPP core phase covers an extended period of intensive observing, modelling, prediction, verification, user-engagement and education activities in the Arctic and Antarctic, on a wide range of time scales from hours to seasons. The Year of Polar Prediction will entail periods of enhanced observational and modelling campaigns in both polar regions. With the purpose to close the gaps in the conventional polar observing systems in regions where the observation network is sparse, routine observations will be enhanced during Special Observing Periods for an extended period of time (several weeks) during YOPP. This will allow carrying out subsequent forecasting system experiments aimed at optimizing observing systems in the polar regions and providing insight into the impact of better polar observations on forecast skills in lower latitudes. With various activities and the involvement of a wide range of stakeholders, YOPP will contribute to the knowledge base needed to managing the opportunities and risks that come with polar climate change.

Nonlinear Gyrokinetic Theory With Polarization Drift

International Nuclear Information System (INIS)

Wang, L.; Hahm, T.S.

2010-01-01

A set of the electrostatic toroidal gyrokinetic Vlasov equation and the Poisson equation, which explicitly includes the polarization drift, is derived systematically by using Lie-transform method. The polarization drift is introduced in the gyrocenter equations of motion, and the corresponding polarization density is derived. Contrary to the wide-spread expectation, the inclusion of the polarization drift in the gyrocenter equations of motion does not affect the expression for the polarization density significantly. This is due to modification of the gyrocenter phase-space volume caused by the electrostatic potential [T. S. Hahm, Phys. Plasmas 3, 4658 (1996)].

Optically pumped polarized H- ion source

International Nuclear Information System (INIS)

Anderson, L.W.

1986-01-01

The current status and future prospects for the optically pumped polarized H - ion source are discussed. At the present time H - ion currents of 60 μA and with a polarization of 65% have been produced. The ion current and polarization can be increased significantly if the optically pumped Na charge exchange target density and polarization can be increased. Studies of wall surfaces that permit many bounces before depolarizing the Na electron spin and studies of radiation trapping in optically pumped Na indicate that the Na target density and polarization can be increased substantially. 27 refs., 6 figs., 2 tabs

Electric Charge Accumulation in Polar and Non-Polar Polymers under Electron Beam Irradiation

Science.gov (United States)

Nagasawa, Kenichiro; Honjoh, Masato; Takada, Tatsuo; Miyake, Hiroaki; Tanaka, Yasuhiro

The electric charge accumulation under an electron beam irradiation (40 keV and 60 keV) was measured by using the pressure wave propagation (PWP) method in the dielectric insulation materials, such as polar polymeric films (polycarbonate (PC), polyethylene-naphthalate (PEN), polyimide (PI), and polyethylene-terephthalate (PET)) and non-polar polymeric films (polystyrene (PS), polypropylene (PP), polyethylene (PE) and polytetrafluoroethylene (PTFE)). The PE and PTFE (non-polar polymers) showed the properties of large amount of electric charge accumulation over 50 C/m3 and long saturation time over 80 minutes. The PP and PS (non-polar polymer) showed the properties of middle amount of charge accumulation about 20 C/m3 and middle saturation time about 1 to 20 minutes. The PC, PEN, PI and PET (polar polymers) showed the properties of small amount of charge accumulation about 5 to 20 C/m3 and within short saturation time about 1.0 minutes. This paper summarizes the relationship between the properties of charge accumulation and chemical structural formula, and compares between the electro static potential distribution with negative charged polymer and its chemical structural formula.

Electric charge accumulation in polar and non-polar polymers under electron beam irradiation

International Nuclear Information System (INIS)

Nagasawa, Kenichiro; Honjoh, Masato; Takada, Tatsuo; Miyake, Hiroaki; Tanaka, Yasuhiro

2010-01-01

The electric charge accumulation under an electron beam irradiation (40 keV and 60 keV) was measured by using the pressure wave propagation (PWP) method in the dielectric insulation materials, such as polar polymeric films (polycarbonate (PC), polyethylene-naphthalate (PEN), polyimide (PI), and polyethylene-terephthalate (PET)) and non-polar polymeric films (polystyrene (PS), polypropylene (PP), polyethylene (PE) and polytetrafluoroethylene (PTFE)). The PE and PTFE (non-polar polymers) showed the properties of large amount of electric charge accumulation over 50 C/m 3 and long saturation time over 80 minutes. The PP and PS (non-polar polymer) showed the properties of middle amount of charge accumulation about 20 C/m 3 and middle saturation time about 1 to 20 minutes. The PC, PEN, PI and PET (polar polymers) showed the properties of small amount of charge accumulation about 5 to 20 C/m 3 and within short saturation time about 1.0 minutes. This paper summarizes the relationship between the properties of charge accumulation and chemical structural formula, and compares between the electro static potential distribution with negative charged polymer and its chemical structural formula. (author)

Accelerating and storing polarized hadron beams

International Nuclear Information System (INIS)

Teng, L.C.

1990-10-01

Polarization hadron experiments at high energies continue to generate surprises. Many questions remain unanswered or unanswerable within the frame work of QCD. These include such basic questions as to why at high energies the polarization analyzing power in pp elastic scattering remains high, why hyperons are produced with high polarizations etc. It is, therefore, interesting to investigate the possibilities of accelerating and storing polarized beams in high energy colliders. On the technical side the recent understanding and confirmation of the actions of partial and multiple Siberian snakes made it possible to contemplate accelerating and storing polarized hadron beams to multi-TeV energies. In this paper, we will examine the equipment, the operation and the procedure required to obtain colliding beams of polarized protons at TeV energies

Spin polarized deuterium

International Nuclear Information System (INIS)

Glyde, H.R.; Hernadi, S.I.

1986-01-01

Several ground state properties of (electron) spin-polarized deuterium (D) such as the energy, single quasiparticle energies and lifetimes, Landau parameters and sound velocities are evaluated. The calculations begin with the Kolos-Wolneiwicz potential and use the Galitskii-FeynmanHartree-Fock (GFHF) approximation. The deuteron nucleas has spin I = 1, and spin states I/sub z/ = 1,0,-1. We explore D 1 , D 2 and D 3 in which, respectively, one spin state only is populated, two states are equally populated, and three states are equally populated. We find the GFHF describes D 1 well, but D 2 and D 3 less well. The Landau parameters, F/sub L/, are small compared to liquid 3 He and very small for doubly polarized D 1 (i.e. the F/sub L/ decrease with nuclear polarization)

Polarization measurement and vertical aperture optimization for obtaining circularly polarized bend-magnet radiation

Energy Technology Data Exchange (ETDEWEB)

Kortright, J.B.; Rice, M.; Hussain, Z. [Lawrence Berkeley National Lab., CA (United States)] [and others

1997-04-01

Growing interest in utilizing circular polarization prompted the design of bend-magnet beamline 9.3.2 at the Advanced Light Source, covering the 30-1500 eV spectral region, to include vertical aperturing capabilities for optimizing the collection of circular polarization above and below the orbit plane. After commissioning and early use of the beamline, a multilayer polarimeter was used to characterize the polarization state of the beam as a function of vertical aperture position. This report partially summarizes the polarimetry measurements and compares results with theoretical calculations intended to simulate experimental conditions.

Some developments in polarized ion sources

International Nuclear Information System (INIS)

Witteveen, G.J.

1979-01-01

Investigations concerning an atomic beam source are presented and a new polarized ion source of a more universal type is introduced. Polarized and unpolarized beams of positively or negatively charged ions can be produced with this new version and the theoretical limits are a polarized negative hydrogen ion beam with an intensity of about 1 mH and a polarized proton beam with an intensity of 10 mH. (C.F.)

Measuring the sea quark polarization

International Nuclear Information System (INIS)

Makdisi, Y.

1993-01-01

Spin is a fundamental degree of freedom and measuring the spin structure functions of the nucleon should be a basic endeavor for hadron physics. Polarization experiments have been the domain of fixed target experiments. Over the years large transverse asymmetries have been observed where the prevailing QCD theories predicted little or no asymmetries, and conversely the latest deep inelastic scattering experiments of polarized leptons from polarized targets point to the possibility that little of the nucleon spin is carried by the valence quarks. The possibility of colliding high luminosity polarized proton beams in the Brookhaven Relativistic Heavy Ion Collider (RHIC) provides a great opportunity to extend these studies and systematically probe the spin dependent parton distributions specially to those reactions that are inaccessible to current experiments. This presentation focuses on the measurement of sea quark and possibly the strange quark polarization utilizing the approved RHIC detectors

New Applications of m-Polar Fuzzy Matroids

Directory of Open Access Journals (Sweden)

Musavarah Sarwar

2017-12-01

Full Text Available Mathematical modelling is an important aspect in apprehending discrete and continuous physical systems. Multipolar uncertainty in data and information incorporates a significant role in various abstract and applied mathematical modelling and decision analysis. Graphical and algebraic models can be studied more precisely when multiple linguistic properties are dealt with, emphasizing the need for a multi-index, multi-object, multi-agent, multi-attribute and multi-polar mathematical approach. An m-polar fuzzy set is introduced to overcome the limitations entailed in single-valued and two-valued uncertainty. Our aim in this research study is to apply the powerful methodology of m-polar fuzzy sets to generalize the theory of matroids. We introduce the notion of m-polar fuzzy matroids and investigate certain properties of various types of m-polar fuzzy matroids. Moreover, we apply the notion of the m-polar fuzzy matroid to graph theory and linear algebra. We present m-polar fuzzy circuits, closures of m-polar fuzzy matroids and put special emphasis on m-polar fuzzy rank functions. Finally, we also describe certain applications of m-polar fuzzy matroids in decision support systems, ordering of machines and network analysis.

Polarization preservation in the AGS

International Nuclear Information System (INIS)

Ratner, L.G.

1983-01-01

The successful operation of a high energy polarized beam at the Argonne Zero Gradient Synchrotron (ZGS) with the concommitant development of depolarizing resonance correction techniques has led to the present project of commissioning such a beam at the Brookhaven Alternating Gradient Synchrotron (AGS). A description of the project was presented at the 1981 National Accelerator Conference. I would like to now present a more detailed description of how we plan to preserve the polarization during acceleration, and to present our game plan for tuning through some 50 resonances and reaching our goal of a 26 GeV polarized proton beam with greater than 60% polarization

The SLAC polarized electron source

International Nuclear Information System (INIS)

Tang, H.; Alley, R.; Frisch, J.

1995-06-01

The SLAC polarized electron source employs a photocathode DC high voltage gun with a loadlock and a YAG pumped Ti:sapphire laser system for colliding beam experiments or a flash lamp pumped Ti:sapphire laser for fixed target experiments. It uses a thin, strained GaAs(100) photocathode, and is capable of producing a pulsed beam with a polarization of ≥80% and a peak current exceeding 10 A. Its operating efficiency has reached 99%. The physics and technology of producing high polarization electron beams from a GaAs photocathode will be reviewed. The prospects of realizing a polarized electron source for future linear colliders will also be discussed

Terahertz broadband polarization converter based on metamaterials

Science.gov (United States)

Li, Yonghua; Zhao, Guozhong

2018-01-01

Based on the metamaterial composed of symmetrical split resonant ring, a broadband reflective terahertz polarization converter is proposed. The numerical simulation shows that it can rotate the polarization direction of linear polarized wave 90° in the range of 0.7-1.8THz and the polarization conversion ratio is over 90%. The reflection coefficient of the two electric field components in the diagonal direction is the same and the phase difference is 180° ,which leads to the cross-polarization rotation.In order to further study the physical mechanism of high polarization conversion, we analyze the surface current distribution of the resonant ring. The polarization converter has potential applications in terahertz wave plate and metamaterial antenna design.

Linear Polarization, Circular Polarization, and Depolarization of Gamma-ray Bursts: A Simple Case of Jitter Radiation

Energy Technology Data Exchange (ETDEWEB)

Mao, Jirong; Wang, Jiancheng, E-mail: jirongmao@mail.ynao.ac.cn [Yunnan Observatories, Chinese Academy of Sciences, 650011 Kunming, Yunnan Province (China)

2017-04-01

Linear and circular polarizations of gamma-ray bursts (GRBs) have been detected recently. We adopt a simplified model to investigate GRB polarization characteristics in this paper. A compressed two-dimensional turbulent slab containing stochastic magnetic fields is considered, and jitter radiation can produce the linear polarization under this special magnetic field topology. Turbulent Faraday rotation measure (RM) of this slab makes strong wavelength-dependent depolarization. The jitter photons can also scatter with those magnetic clumps inside the turbulent slab, and a nonzero variance of the Stokes parameter V can be generated. Furthermore, the linearly and circularly polarized photons in the optical and radio bands may suffer heavy absorptions from the slab. Thus we consider the polarized jitter radiation transfer processes. Finally, we compare our model results with the optical detections of GRB 091018, GRB 121024A, and GRB 131030A. We suggest simultaneous observations of GRB multi-wavelength polarization in the future.

Sky light polarization detection with linear polarizer triplet in light field camera inspired by insect vision.

Science.gov (United States)

Zhang, Wenjing; Cao, Yu; Zhang, Xuanzhe; Liu, Zejin

2015-10-20

Stable information of a sky light polarization pattern can be used for navigation with various advantages such as better performance of anti-interference, no "error cumulative effect," and so on. But the existing method of sky light polarization measurement is weak in real-time performance or with a complex system. Inspired by the navigational capability of a Cataglyphis with its compound eyes, we introduce a new approach to acquire the all-sky image under different polarization directions with one camera and without a rotating polarizer, so as to detect the polarization pattern across the full sky in a single snapshot. Our system is based on a handheld light field camera with a wide-angle lens and a triplet linear polarizer placed over its aperture stop. Experimental results agree with the theoretical predictions. Not only real-time detection but simple and costless architecture demonstrates the superiority of the approach proposed in this paper.

Detecting spin polarization of nano-crystalline manganese doped zinc oxide thin film using circular polarized light

Energy Technology Data Exchange (ETDEWEB)

El-Sayed, H.M., E-mail: h_m_elsaid@hotmail.com

2016-02-01

The presence of spin polarization in Mn-doped ZnO thin film is very important for spintronic applications. Spin polarization was detected using simple method. This method depends on measuring the optical transmittance using circular polarized light in visible and near infra-red region. It was found that, there is a difference in the optical energy gap of the film for circular left and circular polarized light. For temperatures > 310 K the difference in energy gap is vanished. This result is confirmed by measuring the magnetic hysteresis of the film. This work introduces a promising method for measuring the ferromagnetism in diluted magnetic semiconductors. - Highlights: • Highly oriented c-axis of Mn-ZnO thin film doped with nitrogen is prepared. • The optical energy gap depends on the state of circularly polarized light. • The presence of spin polarization is confirmed using simple optical method. • Magnetic measurements are consistent with the results of the optical method.

Single photon detector with high polarization sensitivity.

Science.gov (United States)

Guo, Qi; Li, Hao; You, LiXing; Zhang, WeiJun; Zhang, Lu; Wang, Zhen; Xie, XiaoMing; Qi, Ming

2015-04-15

Polarization is one of the key parameters of light. Most optical detectors are intensity detectors that are insensitive to the polarization of light. A superconducting nanowire single photon detector (SNSPD) is naturally sensitive to polarization due to its nanowire structure. Previous studies focused on producing a polarization-insensitive SNSPD. In this study, by adjusting the width and pitch of the nanowire, we systematically investigate the preparation of an SNSPD with high polarization sensitivity. Subsequently, an SNSPD with a system detection efficiency of 12% and a polarization extinction ratio of 22 was successfully prepared.

A novel polarization demodulation method using polarization beam splitter (PBS) for dynamic pressure sensor

Science.gov (United States)

Su, Yang; Zhou, Hua; Wang, Yiming; Shen, Huiping

2018-03-01

In this paper we propose a new design to demodulate polarization properties induced by pressure using a PBS (polarization beam splitter), which is different with traditional polarimeter based on the 4-detector polarization measurement approach. The theoretical model is established by Muller matrix method. Experimental results confirm the validity of our analysis. Proportional relationships and linear fit are found between output signal and applied pressure. A maximum sensitivity of 0.092182 mv/mv is experimentally achieved and the frequency response exhibits a <0.14 dB variation across the measurement bandwidth. The sensitivity dependence on incident SOP (state of polarization) is investigated. The simple and all-fiber configuration, low-cost and high speed potential make it promising for fiber-based dynamic pressure sensing.

POLAR on board of the Tiangong 2 Chinese space station: measuring the polarization of hard X-rays photons, in particular the polarization of prompt photons from gamma ray bursts.

Science.gov (United States)

Produit, Nicolas

2012-07-01

POLAR is an homogeneous wide field Compton polarimeter using plastic scintillators and multichannel photomultipliers. The goal of this polarimeter is to measure with controlled systematics the polarization of hard X-ray emitted by unpredictable transient sources The instrument energy range sensitivity is optimized for the detection of the prompt emission of Gamma-Ray Bursts (GRB). Monte-Carlo studies and calibration data collected in polarized photon beams predict that POLAR will be able to measure the polarization degree of 10 GRB per year with a combined systematics and statistical accuracy of better then 10%. POLAR will be mounted outside of the Tiangong 2 Chinese space station that will be launched in space in 2014.

Relative abundance and distribution of bacteria in the gut of ...

African Journals Online (AJOL)

Escherichia coli, Aeromonas hydrophila, Salmonella typhi and Pseudomonas aeruginosa were the most abundant species in the samples from Epe Lagoon while Escherichia coli, Aeromonas hydrophila, Proteus vulgaris and Pseudomonas aeruginosa were predominant in Badagry Creek. It was noteworthy that Citrobacter ...

Theory of Inclusive Scattering of Polarized Electrons by Polarized $^{3}$He and the Neutron Form Factors

OpenAIRE

Atti, C. Ciofi degli; Pace, E.; Salmé, G.

1993-01-01

The theory of inclusive lepton scattering of polarized leptons by polarized J = 1/2 hadrons is presented and the origin of different expressions for the polarized nuclear response function appearing in the literature is explained. The sensitivity of the longitudinal asymmetry upon the neutron form factors is investigated.

Loss-free neutron polarization

International Nuclear Information System (INIS)

Mueller, S.; Badurek, G.

2001-01-01

Full text: The so-called concept of 'dynamical' neutron polarization should allow to polarize a beam of thermal or cold neutrons without loosing even one particle. It is based upon the spin-dependent energy splitting of monochromatic neutrons in a NMR-like arrangement of crossed static and oscillating magnetic fields, which causes different interaction times of the two opposite spin states with a subsequent static precession field. If this Larmor rotation is stopped at the moment when the two states are oriented parallel to a given direction, the beam will be fully polarized, on the cost of a tiny energy difference between the two states, however. At pulsed neutron sources this method should even allow loss-free polarization of polychromatic neutrons, if by a suitably chosen time dependence of either the precession or the splitting field the flight-time dispersion of the particles is adequately taken into account. However, until now this quite sophisticated method has not been realized experimentally. We have performed detailed analytical and numerical simulations of such a dynamical polarization facility for pulsed neutron beams in order to proof its feasibility. It turns out that the required space and time dependence of the magnetic fields involved are well within the scope of existing magnet technology. Ref. 1 (author)

Coherence and Polarization of Polarization Speckle Generated by Depolarizers and Their Changes through Complex ABCD Matrix

DEFF Research Database (Denmark)

Ma, Ning; Hanson, Steen Grüner; Lee, Tim K.

2015-01-01

Recent research work on speckle patterns indicates a variation of the polarization state during propagation and its nonuniformly spatial distribution. The preliminary step for the investigation of this polarization speckle is the generation of the corresponding field. In this paper, a kind...... of special depolarizer: the random roughness birefringent screen (RRBS) is introduced to meet this requirement. The statistical properties of the field generated by the depolarizer is investigated and illustrated in terms of the 2x2 beam coherence and polarization matrix (BCPM) with the corresponding degree...... of coherence (DoC). and degree of polarization (DoP) P. The changes of the coherence and polarization when the speckle field propagates through any optical system are analysed within the framework of the complex ABCD-matrix theory....

Proton polarization in the photodisintegration of the deuteron by linearly polarized 400- and 500-MeV γ rays

International Nuclear Information System (INIS)

Bratashevskii, A.S.; Gorbenko, V.G.; Gushchin, V.A.

1982-01-01

The polarization of the recoil protons at the angle theta(/sub p/ = 90 0 has been measured in the photodisintegration of the deuteron by linearly polarized 400- and 500-MeV γ rays. For the first time, all of the following observables have been determined under identical experimental conditions: Σ, the asymmetry of the cross sections; P/sub y/, the polarization of the recoil proton; and T 1 , the asymmetry of the nucleon polarization for the case of linearly polarized γ rays

Efficient composite broadband polarization retarders and polarization filters

Science.gov (United States)

Dimova, E.; Ivanov, S. S.; Popkirov, G.; Vitanov, N. V.

2014-12-01

A new type of broadband polarization half-wave retarder and narrowband polarization filters are described and experimentally tested. Both, the retarders and the filters are designed as composite stacks of standard optical half-wave plates, each of them twisted at specific angles. The theoretical background of the proposed optical devices was obtained by analogy with the method of composite pulses, known from the nuclear and quantum physics. We show that combining two composite filters built from different numbers and types of waveplates, the transmission spectrum is reduced from about 700 nm to about 10 nm width.We experimentally demonstrate that this method can be applied to different types of waveplates (broadband, zero-order, multiple order, etc.).

Polarization-controlled asymmetric excitation of surface plasmons

KAUST Repository

Xu, Quan

2017-08-28

Free-space light can be coupled into propagating surface waves at a metal–dielectric interface, known as surface plasmons (SPs). This process has traditionally faced challenges in preserving the incident polarization information and controlling the directionality of the excited SPs. The recently reported polarization-controlled asymmetric excitation of SPs in metasurfaces has attracted much attention for its promise in developing innovative plasmonic devices. However, the unit elements in these works were purposely designed in certain orthogonal polarizations, i.e., linear or circular polarizations, resulting in limited two-level polarization controllability. Here, we introduce a coupled-mode theory to overcome this limit. We demonstrated theoretically and experimentally that, by utilizing the coupling effect between a pair of split-ring-shaped slit resonators, exotic asymmetric excitation of SPs can be obtained under the x-, y-, left-handed circular, and right-handed circular polarization incidences, while the polarization information of the incident light can be preserved in the excited SPs. The versatility of the presented design scheme would offer opportunities for polarization sensing and polarization-controlled plasmonic devices.

Dynamic nuclear polarization of irradiated target materials

International Nuclear Information System (INIS)

Seely, M.L.

1982-01-01

Polarized nucleon targets used in high energy physics experiments usually employ the method of dynamic nuclear polarization (DNP) to polarize the protons or deuterons in an alcohol. DNP requires the presence of paramagnetic centers, which are customarily provided by a chemical dopant. These chemically doped targets have a relatively low polarizable nucleon content and suffer from loss of polarization when subjected to high doses of ionizing radiation. If the paramagnetic centers formed when the target is irradiated can be used in the DNP process, it becomes possible to produce targets using materials which have a relatively high polarizable nucleon content, but which are not easily doped by chemical means. Furthermore, the polarization of such targets may be much more radiation resistant. Dynamic nuclear polarization in ammonia, deuterated ammonia, ammonium hydroxide, methylamine, borane ammonia, butonal, ethane and lithium borohydride has been studied. These studies were conducted at the Stanford Linear Accelerator Center using the Yale-SLAC polarized target system. Results indicate that the use of ammonia and deuterated ammonia as polarized target materials would make significant increases in polarized target performance possible

Circularly Polarized Microwave Antenna Element with Very Low Off-Axis Cross-Polarization

Science.gov (United States)

Greem. David; DuToit, Cornelis

2013-01-01

The goal of this work was to improve off-axis cross-polarization performance and ease of assembly of a circularly polarized microwave antenna element. To ease assembly, the initial design requirement of Hexweb support for the internal circuit part, as well as the radiating disks, was eliminated. There is a need for different plating techniques to improve soldering. It was also desirable to change the design to eliminate soldering as well as the need to use the Hexweb support. Thus, a technique was developed to build the feed without using solder, solving the lathing and soldering issue. Internal parts were strengthened by adding curvature to eliminate Hexweb support, and in the process, the new geometries of the internal parts opened the way for improving the off-axis cross-polarization performance as well. The radiating disks curvatures were increased for increased strength, but it was found that this also improved crosspolarization. Optimization of the curvatures leads to very low off-axis cross-polarization. The feed circuit was curved into a cylinder for improved strength, eliminating Hexweb support. An aperture coupling feed mechanism eliminated the need for feed pins to the disks, which would have required soldering. The aperture coupling technique also improves cross-polarization performance by effectively exciting the radiating disks very close to the antenna s central axis of symmetry. Because of the shape of the parts, it allowed for an all-aluminum design bolted together and assembled with no solder needed. The advantage of a solderless design is that the reliability is higher, with no single-point failure (solder), and no need for special plating techniques in order to solder the unit together. The shapes (curved or round) make for a more robust build without extra support materials, as well as improved offaxis cross-polarization.

Effect of asymmetrical transfer coefficients of a non-polarizing beam splitter on the nonlinear error of the polarization interferometer

Science.gov (United States)

Zhao, Chen-Guang; Tan, Jiu-Bin; Liu, Tao

2010-09-01

The mechanism of a non-polarizing beam splitter (NPBS) with asymmetrical transfer coefficients causing the rotation of polarization direction is explained in principle, and the measurement nonlinear error caused by NPBS is analyzed based on Jones matrix theory. Theoretical calculations show that the nonlinear error changes periodically, and the error period and peak values increase with the deviation between transmissivities of p-polarization and s-polarization states. When the transmissivity of p-polarization is 53% and that of s-polarization is 48%, the maximum error reaches 2.7 nm. The imperfection of NPBS is one of the main error sources in simultaneous phase-shifting polarization interferometer, and its influence can not be neglected in the nanoscale ultra-precision measurement.

Polarized coincidence electroproduction

International Nuclear Information System (INIS)

Heimann, R.L.

1975-03-01

A study is made of the inclusive electroproduction of single hadrons off a polarized target. Bjorken scaling laws and the hadron azimuthal distribution are derived from the quark parton model. The polarization asymmetries scale when the target spin is along the direction of the virtual photon, and (apart from significant exception) vanish for transverse spin. These results have a simple explanation; emphasis is given both to the general mathematical formalism and to intuitive physical reasoning. Through this framework other cases are considered: quarks with anomalous magnetic moment; renormalization group effects and asymptotic freedom; production of vector mesons (whose spin state is analysed by their decay); relation to large transverse momentum hadron production; and a covariant parton model calculation. Spin 0 partons and Regge singularities are also considered. All of these cases (apart from the last two) modify the pattern of conclusions. Vector meson production shows polarization enhancements in the density matrix element rhosub(0+); the renormalization group approach does not lead to any significant suppressions. They are also less severe in parton models for large Psub(T) hadrons, and are not supported by the covariantly formulated calculation. The origins of these differences are isolated and used to exemplify the sensitivity polarized hadron electroproduction has to delicate detail that is otherwise concealed. (author)

Σ+ and Σ- production polarizations

International Nuclear Information System (INIS)

Cooper, P.S.; Anderson, E.W.; Ankenbrandt, C.

1982-11-01

We report preliminary results from Fermilab experiment E497 on the production polarizations of Σ + and Σ - hyperons. Hyperons were produced inclusively at non zero production angles by 400 GeV/c protons incident on a Cu target. The polarization was analyzed by the weak decay asymmetry in the hadronic decay modes Σ + → pπ 0 and Σ - → nπ - . Based upon samples of 38,000 Σ + and 317,000 Σ - decays we observe polarizations as a function of P/sub t/ which average 22% at an X of 0.53 for Σ + and 40% at X of 0.68 and 0.78 for Σ - . The direction of polarization for both Σ + and Σ - is in the direction of K/sub -p/ x K/sub Σ/ where the K's are the momentum vectors of the incident proton and produced hyperon respectively. This is opposite to the direction of polarization of inclusively produced lambdas

Polarized source upgrading

International Nuclear Information System (INIS)

Clegg, T.B.; Rummel, R.L.; Carter, E.P.; Westerfeldt, C.R.; Lovette, A.W.; Edwards, S.E.

1985-01-01

The decision was made this past year to move the Lamb-shift polarized ion source which was first installed in the laboratory in 1970. The motivation was the need to improve the flexibility of spin-axis orientation by installing the ion source with a new Wien-filter spin precessor which is capable of rotating physically about the beam axis. The move of the polarized source was accomplished in approximately two months, with the accelerator being turned off for experiments during approximately four weeks of this time. The occasion of the move provided the opportunity to rewire completely the entire polarized ion source frame and to rebuild approximately half of the electronic chassis on the source. The result is an ion source which is now logically wired and carefully documented. Beams obtained from the source are much more stable than those previously available

STANFORD: Highly polarized SLC electron beams

International Nuclear Information System (INIS)

Anon.

1993-01-01

Full text: Using specialized photocathodes made with 'strained' gallium arsenide, physicists at the Stanford Linear Accelerator Center (SLAC) have generated electron beams with polarizations in excess of 60 percent a year ahead of schedule. Together with recent luminosity increases, this breakthrough will have a major impact on the physics output of the Stanford Linear Collider (SLC). Beam polarization was almost tripled using photocathodes in which a gallium arsenide layer was grown epitaxially over a substrate of gallium arsenide phosphide. The mismatch between these two layers deforms the crystal structure and removes a degeneracy in the valence band structure, permitting selective optical pumping of one unique spin state. Whereas conventional gallium arsenide photocathodes are limited to 50 percent polarization because of this degeneracy (and realistic cathodes fall substantially below this theoretical limit), such strained crystal lattices have the potential to yield polarizations close to 100 percent. Polarization enhancement with strained lattices was first demonstrated in 1991 by a SLAC/Wisconsin/ Berkeley group (May 1991, page 6) with a 71 percent polarization in a laboratory experiment. More recently this group has achieved polarization in excess of 90 percent, reported last November at the Nagoya Spin Symposium. (In a complementary development, a Japanese KEK/ Nagoya/KEK obtains polarized beams using a 'superlattice' - May 1991, page 4.) The 1993 SLC run, the strained gallium arsenide photocathode technique's debut in an operating particle accelerator, has proved to be a resounding, unqualified success - as have physics experiments on the Z particles produced by the highly polarized beam. A conservative approach was called for, due to concerns about possible charge saturation effects. A relatively thick (0.3 micron) gallium arsenide layer was used for the photocathode in the SLC polarized electron source. With a titanium

An analytical model of flagellate hydrodynamics

International Nuclear Information System (INIS)

Dölger, Julia; Bohr, Tomas; Andersen, Anders

2017-01-01

Flagellates are unicellular microswimmers that propel themselves using one or several beating flagella. We consider a hydrodynamic model of flagellates and explore the effect of flagellar arrangement and beat pattern on swimming kinematics and near-cell flow. The model is based on the analytical solution by Oseen for the low Reynolds number flow due to a point force outside a no-slip sphere. The no-slip sphere represents the cell and the point force a single flagellum. By superposition we are able to model a freely swimming flagellate with several flagella. For biflagellates with left–right symmetric flagellar arrangements we determine the swimming velocity, and we show that transversal forces due to the periodic movements of the flagella can promote swimming. For a model flagellate with both a longitudinal and a transversal flagellum we determine radius and pitch of the helical swimming trajectory. We find that the longitudinal flagellum is responsible for the average translational motion whereas the transversal flagellum governs the rotational motion. Finally, we show that the transversal flagellum can lead to strong feeding currents to localized capture sites on the cell surface. (paper)