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Sample records for bobtail squid euprymna

  1. Characterizing the host and symbiont proteomes in the association between the Bobtail squid, Euprymna scolopes, and the bacterium, Vibrio fischeri.

    Directory of Open Access Journals (Sweden)

    Tyler R Schleicher

    Full Text Available The beneficial symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and the bioluminescent bacterium, Vibrio fischeri, provides a unique opportunity to study host/microbe interactions within a natural microenvironment. Colonization of the squid light organ by V. fischeri begins a lifelong association with a regulated daily rhythm. Each morning the host expels an exudate from the light organ consisting of 95% of the symbiont population in addition to host hemocytes and shed epithelial cells. We analyzed the host and symbiont proteomes of adult squid exudate and surrounding light organ epithelial tissue using 1D- and 2D-polyacrylamide gel electrophoresis and multidimensional protein identification technology (MudPIT in an effort to understand the contribution of both partners to the maintenance of this association. These proteomic analyses putatively identified 1581 unique proteins, 870 proteins originating from the symbiont and 711 from the host. Identified host proteins indicate a role of the innate immune system and reactive oxygen species (ROS in regulating the symbiosis. Symbiont proteins detected enhance our understanding of the role of quorum sensing, two-component signaling, motility, and detoxification of ROS and reactive nitrogen species (RNS inside the light organ. This study offers the first proteomic analysis of the symbiotic microenvironment of the adult light organ and provides the identification of proteins important to the regulation of this beneficial association.

  2. The Hawaiian bobtail squid (Euprymna scolopes): a model to study the molecular basis of eukaryote-prokaryote mutualism and the development and evolution of morphological novelties in cephalopods.

    Science.gov (United States)

    Lee, Patricia N; McFall-Ngai, Margaret J; Callaerts, Patrick; de Couet, H Gert

    2009-11-01

    The Hawaiian bobtail squid, Euprymna scolopes, is a cephalopod whose small size, short lifespan, rapid growth, and year-round availability make it suitable as a model organism. E. scolopes is studied in three principal contexts: (1) as a model of cephalopod development; (2) as a model of animal-bacterial symbioses; and (3) as a system for studying adaptations of tissues that interact with light. E. scolopes embryos can be obtained continually and can be reared in the laboratory over an entire generation. The embryos and protective chorions are optically clear, facilitating in situ developmental observations, and can be manipulated experimentally. Many molecular protocols have been developed for studying E. scolopes development. This species is best known, however, for its symbiosis with the luminous marine bacterium Vibrio fischeri and has been used to study determinants of symbiont specificity, the influence of symbiosis on development of the squid light organ, and the mechanisms by which a stable association is achieved. Both partners can be grown independently under laboratory conditions, a feature that offers the unusual opportunity to manipulate the symbiosis experimentally. Molecular and genetic tools have been developed for V. fischeri, and a large expressed sequence tag (EST) database is available for the host symbiotic tissues. Additionally, comparisons between light organ form and function to those of the eye can be made. Both types of tissue interact with light, but have divergent embryonic development. As such, they offer an opportunity to study the molecular basis for the evolution of morphological novelties.

  3. Leisingera sp. JC1, a Bacterial Isolate from Hawaiian Bobtail Squid Eggs, Produces Indigoidine and Differentially Inhibits Vibrios.

    Science.gov (United States)

    Gromek, Samantha M; Suria, Andrea M; Fullmer, Matthew S; Garcia, Jillian L; Gogarten, Johann Peter; Nyholm, Spencer V; Balunas, Marcy J

    2016-01-01

    Female members of many cephalopod species house a bacterial consortium in the accessory nidamental gland (ANG), part of the reproductive system. These bacteria are deposited into eggs that are then laid in the environment where they must develop unprotected from predation, pathogens, and fouling. In this study, we characterized the genome and secondary metabolite production of Leisingera sp. JC1, a member of the roseobacter clade (Rhodobacteraceae) of Alphaproteobacteria isolated from the jelly coat of eggs from the Hawaiian bobtail squid, Euprymna scolopes. Whole genome sequencing and MLSA analysis revealed that Leisingera sp. JC1 falls within a group of roseobacters associated with squid ANGs. Genome and biochemical analyses revealed the potential for and production of a number of secondary metabolites, including siderophores and acyl-homoserine lactones involved with quorum sensing. The complete biosynthetic gene cluster for the pigment indigoidine was detected in the genome and mass spectrometry confirmed the production of this compound. Furthermore, we investigated the production of indigoidine under co-culture conditions with Vibrio fischeri, the light organ symbiont of E. scolopes, and with other vibrios. Finally, both Leisingera sp. JC1 and secondary metabolite extracts of this strain had differential antimicrobial activity against a number of marine vibrios, suggesting that Leisingera sp. JC1 may play a role in host defense against other marine bacteria either in the eggs and/or ANG. These data also suggest that indigoidine may be partially, but not wholly, responsible for the antimicrobial activity of this squid-associated bacterium.

  4. The cephalopod arm crown: appendage formation and differentiation in the Hawaiian bobtail squid Euprymna scolopes

    OpenAIRE

    Nödl, Marie-Therese; Kerbl, Alexandra; Walzl, Manfred G.; Gerd B Müller; de Couet, Heinz Gert

    2016-01-01

    Background Cephalopods are a highly derived class of molluscs that adapted their body plan to a more active and predatory lifestyle. One intriguing adaptation is the modification of the ventral foot to form a bilaterally symmetric arm crown, which constitutes a true morphological novelty in evolution. In addition, this structure shows many diversifications within the class of cephalopods and therefore offers an interesting opportunity to study the molecular underpinnings of the emergence of p...

  5. Does predation risk affect mating behavior? An experimental test in dumpling squid (Euprymna tasmanica.

    Directory of Open Access Journals (Sweden)

    Amanda M Franklin

    Full Text Available INTRODUCTION: One of the most important trade-offs for many animals is that between survival and reproduction. This is particularly apparent when mating increases the risk of predation, either by increasing conspicuousness, reducing mobility or inhibiting an individual's ability to detect predators. Individuals may mitigate the risk of predation by altering their reproductive behavior (e.g. increasing anti-predator responses to reduce conspicuousness. The degree to which individuals modulate their reproductive behavior in relation to predation risk is difficult to predict because both the optimal investment in current and future reproduction (due to life-history strategies and level of predation risk may differ between the sexes and among species. Here, we investigate the effect of increased predation risk on the reproductive behavior of dumpling squid (Euprymna tasmanica. RESULTS: Females, but not males, showed a substantial increase in the number of inks (an anti-predator behavior before mating commenced in the presence of a predator (sand flathead Platycephalus bassensis. However, predation risk did not affect copulation duration, the likelihood of mating, female anti-predator behavior during or after mating or male anti-predator behavior at any time. CONCLUSIONS: Inking is a common anti-predator defense in cephalopods, thought to act like a smokescreen, decoy or distraction. Female dumpling squid are probably using this form of defense in response to the increase in predation risk prior to mating. Conversely, males were undeterred by the increase in predation risk. A lack of change in these variables may occur if the benefit of completing mating outweighs the risk of predation. Prioritizing current reproduction, even under predation risk, can occur when the chance of future reproduction is low, there is substantial energetic investment into mating, or the potential fitness payoffs of mating are high.

  6. Transcriptome analysis of the white body of the squid Euprymna tasmanica with emphasis on immune and hematopoietic gene discovery.

    Directory of Open Access Journals (Sweden)

    Karla A Salazar

    Full Text Available In the mutualistic relationship between the squid Euprymna tasmanica and the bioluminescent bacterium Vibrio fischeri, several host factors, including immune-related proteins, are known to interact and respond specifically and exclusively to the presence of the symbiont. In squid and octopus, the white body is considered to be an immune organ mainly due to the fact that blood cells, or hemocytes, are known to be present in high numbers and in different developmental stages. Hence, the white body has been described as the site of hematopoiesis in cephalopods. However, to our knowledge, there are no studies showing any molecular evidence of such functions. In this study, we performed a transcriptomic analysis of white body tissue of the Southern dumpling squid, E. tasmanica. Our primary goal was to gain insights into the functions of this tissue and to test for the presence of gene transcripts associated with hematopoietic and immune processes. Several hematopoiesis genes including CPSF1, GATA 2, TFIID, and FGFR2 were found to be expressed in the white body. In addition, transcripts associated with immune-related signal transduction pathways, such as the toll-like receptor/NF-κβ, and MAPK pathways were also found, as well as other immune genes previously identified in E. tasmanica's sister species, E. scolopes. This study is the first to analyze an immune organ within cephalopods, and to provide gene expression data supporting the white body as a hematopoietic tissue.

  7. Developmental expression of apterous/Lhx2/9 in the sepiolid squid Euprymna scolopes supports an ancestral role in neural development.

    Science.gov (United States)

    Farfán, Claudia; Shigeno, Shuichi; Nödl, Marie-Therese; de Couet, H Gert

    2009-01-01

    The transcription factors Apterous/Lhx2/9 play many pivotal roles in the development of protostomes and deuterostomes, most notably limb patterning, eye morphogenesis, and brain development. Full-length apterous/lhx2/9 homologs have been isolated from several invertebrate species, but hitherto not from a lophotrochozoan. Here, we report the isolation, characterization, and spatio-temporal expression of apterous in the sepiolid squid Euprymna scolopes. The isolated composite cDNA encodes a hypothetical protein of 448 amino acid residues with a typical LIM-homeodomain (LIM-HD) structure and the greatest overall sequence similarity to vertebrate Lhx2/9 proteins. The Euprymna scolopes apterous (Es-ap) expression patterns provided no indication of a role in the early dorso/ventral patterning or growth of the arm crown that showed expression only in two ventral cords running in parallel inside the arms and tentacles and at the base of the suckers, a region rich in nerve endings and chemosensory neurons. The Es-ap hybridization signal was also conspicuous in the eyes, olfactory organs, optic lobes, and in several lobes of the supraesophageal mass, among these the olfactory and vertical lobes, and paravertical bodies. The observed expression patterns suggest gene involvement in eye morphogenesis and neural wiring of sensory structures, including those for olfaction and vision.

  8. The complete mitochondrial genomes of deep-sea squid (Bathyteuthis abyssicola), bob-tail squid (Semirossia patagonica) and four giant cuttlefish (Sepia apama, S. latimanus, S. lycidas and S. pharaonis), and their application to the phylogenetic analysis of Decapodiformes.

    Science.gov (United States)

    Kawashima, Yuumi; Nishihara, Hidenori; Akasaki, Tetsuya; Nikaido, Masato; Tsuchiya, Kotaro; Segawa, Susumu; Okada, Norihiro

    2013-12-01

    We determined the complete mitochondrial (mt) genomes of the deep-sea squid (Bathyteuthis abyssicola; supperfamily Bathyteuthoidea), the bob-tail squid (Semirossia patagonica; order Sepiolida) and four giant cuttlefish (Sepia apama, S. latimanus, S. lycidas and S. pharaonis; order Sepiida). The unique structures of the mt genomes of Bathyteuthis and Semirossia provide new information about the evolution of decapodiform mt genomes. We show that the mt genome of B. abyssicola, like those of other oegopsids studied so far, has two long duplicated regions that include seven genes (COX1-3, ATP6 and ATP8, tRNA(Asn), and either ND2 or ND3) and that one of the duplicated COX3 genes has lost its function. The mt genome of S. patagonica is unlike any other decapodiforms and, like Nautilus, its ATP6 and ATP8 genes are not adjacent to each other. The four giant cuttlefish have identical mt gene order to other cuttlefish determined to date. Molecular phylogenetic analyses using maximum likelihood and Bayesian methods suggest that traditional order Sepioidea (Sepiolida+Sepiida) is paraphyletic and Sepia (cuttlefish) has the sister-relationship with all other decapodiforms. Taking both the phylogenetic analyses and the mt gene order analyses into account, it is likely that the octopus-type mt genome is an ancestral state and that it had maintained from at least the Cephalopoda ancestor to the common ancestor of Oegopsida, Myopsida and Sepiolida.

  9. The Vibrio fischeri quorum-sensing systems ain and lux sequentially induce luminescence gene expression and are important for persistence in the squid host.

    Science.gov (United States)

    Lupp, Claudia; Urbanowski, Mark; Greenberg, E Peter; Ruby, Edward G

    2003-10-01

    Bacterial quorum sensing using acyl-homoserine lactones (acyl-HSLs) as cell-density dependent signalling molecules is important for the transcriptional regulation of many genes essential in the establishment and the maintenance of bacteria-host associations. Vibrio fischeri, the symbiotic partner of the Hawaiian bobtail squid Euprymna scolopes, possesses two distinct acyl-HSL synthase proteins, LuxI and AinS. Whereas the cell density-dependent regulation of luminescence by the LuxI-produced signal is a well-described phenomenon, and its role in light organ symbiosis has been defined, little is known about the ain system. We have investigated the impact of the V. fischeri acyl-HSL synthase AinS on both luminescence and symbiotic colonization. Through phenotypic studies of V. fischeri mutants we have found that the AinS-signal is the predominant inducer of luminescence expression in culture, whereas the impact of the LuxI-signal is apparent only at the high cell densities occurring in symbiosis. Furthermore, our studies revealed that ainS regulates activities essential for successful colonization of E. scolopes, i.e. the V. fischeri ainS mutant failed to persist in the squid light organ. Mutational inactivation of the transcriptional regulator protein LuxO in the ainS mutant partially or completely reversed all the observed phenotypes, demonstrating that the AinS-signal regulates expression of downstream genes through the inactivation of LuxO. Taken together, our results suggest that the two quorum-sensing systems in V. fischeri, ain and lux, sequentially induce the expression of luminescence genes and possibly other colonization factors.

  10. An annotated cDNA library of juvenile Euprymna scolopes with and without colonization by the symbiont Vibrio fischeri

    Directory of Open Access Journals (Sweden)

    Tong Deyan

    2006-06-01

    Full Text Available Abstract Background Biologists are becoming increasingly aware that the interaction of animals, including humans, with their coevolved bacterial partners is essential for health. This growing awareness has been a driving force for the development of models for the study of beneficial animal-bacterial interactions. In the squid-vibrio model, symbiotic Vibrio fischeri induce dramatic developmental changes in the light organ of host Euprymna scolopes over the first hours to days of their partnership. We report here the creation of a juvenile light-organ specific EST database. Results We generated eleven cDNA libraries from the light organ of E. scolopes at developmentally significant time points with and without colonization by V. fischeri. Single pass 3' sequencing efforts generated 42,564 expressed sequence tags (ESTs of which 35,421 passed our quality criteria and were then clustered via the UIcluster program into 13,962 nonredundant sequences. The cDNA clones representing these nonredundant sequences were sequenced from the 5' end of the vector and 58% of these resulting sequences overlapped significantly with the associated 3' sequence to generate 8,067 contigs with an average sequence length of 1,065 bp. All sequences were annotated with BLASTX (E-value Conclusion Both the number of ESTs generated from each library and GO categorizations are reflective of the activity state of the light organ during these early stages of symbiosis. Future analyses of the sequences identified in these libraries promise to provide valuable information not only about pathways involved in colonization and early development of the squid light organ, but also about pathways conserved in response to bacterial colonization across the animal kingdom.

  11. Squid Rolls

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Ingredients: 250 grams of squid, 100 grams of broccoli. a pinch of green tea, 50 grams of bamboo shoots, 100 grams of various kinds of mushroom, 50 grams of chicken broth, chopped green union, ginger, cooking wine, salt, pep per and MSG.

  12. Holographic SQUID

    CERN Document Server

    Takeuchi, Shingo

    2013-01-01

    We propose a holographic model of the SQUID (Superconducting QUantum Interference Device) composed of two Josephson junctions connected each other in a circle with the magnetic flux penetrating the circuit of the SQUID and the supercurrents flowing in both Josephson junction. The gravity in this paper is the Einstein-Maxwell-complex scalar field model on the four-dimensional Anti-de Sitter Schwarzschild black brane geometry in which one space direction is compactified into a circle, and we arrange the profile of the coefficient of the time component of the gauge field having the role for the chemical potential of the cooper pair. The magnetic flux is involved by the rewriting of the surface integral of the magnetic field to the contour integral of the gauge field.

  13. Japanese Bobtail: vertebral morphology and genetic characterization of an established cat breed.

    Science.gov (United States)

    Pollard, Rachel E; Koehne, Amanda L; Peterson, Carlyn B; Lyons, Leslie A

    2015-08-01

    Several cat breeds are defined by morphological variation of the tail. The Japanese Bobtail is a breed that has been accepted for registration only within the past 50 years; however, the congenital kinked tail variants defining this breed were documented in the Far East centuries ago and the cats are considered 'good luck' in several Asian cultures. The recent discovery of the mutation for the tailless Manx phenotype has demonstrated that the Japanese Bobtail does not have a causative mutation in the same gene (T-Box). Here, a simple segregation analysis of cats bred from a pedigreed Japanese Bobtail demonstrated a simple autosomal dominant mode of inheritance with variable expression of the tail length and kink placement. Unexpectedly, radiological examinations of the entire vertebral column of kink-tailed cats indicated variation from the normal vertebral feline formula (C7, T13, L7, S3, Cd20-24), including cats with mostly one reduction of thoracic vertebrae (C7, T12, L7, S3), and an average of 15.8 caudal vertebrae. A few cats had variation in the number of cervical vertebrae. Several transitional vertebrae and anomalous ribs were noted. One cat had a bifid vertebra in the tail. Most cats had hemivertebrae that were usually included in the tail kink, one of which was demonstrated by gross pathology and histopathology. The abnormal vertebral formula or the placement of the kink in the tail did not coincide with morbidity or mortality.

  14. The risks of Bobtail truck LPG (Liquefied Petroleum Gases) distribution in urban areas

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Cesar A. [Det Norske Veritas (DNV), Oslo (Norway)], e-mail: cesar.leal@dnv.com

    2008-07-01

    The use of 'Bobtail' trucks (6 and 9 ton) for distribution of Liquefied Petroleum Gas (LPG) in Brazilian cities represents a new and mobile source of risk. In this paper, it will be presented a discussion about some of the possible accident scenarios that can occur with this kind of vehicle, with emphasis on the possible consequences (BLEVE/fireball). The goal is to spread information and call attention of Government Authorities and gas distribution companies, as well as the general public, about this source of risk. In the case of a 9 ton fireball, fatalities could be expected up to 176 m, according to TNO models. Collapse of the tank engulfed in fire is expected in 10 to 20 minutes, a too short time interval for the arrival of a fire brigade and control of the situation. Suggestions are presented for the use of insulating coating in the tanks capable of withstanding an external fire for two hours without collapsing and the realization of a risk study for estimation of the impact of the use of insulation in terms of risk reduction for the population and a comparison of risks associated to the two forms of LPG distribution. (author)

  15. The SQUID Handbook

    CERN Document Server

    Braginski, Alex I

    2006-01-01

    This two-volume handbook offers a comprehensive and well coordinated presentation of SQUIDs (Superconducting Quantum Interference Devices), including device fundamentals, design, technology, system construction and multiple applications. It is intended to bridge the gap between fundamentals and applications, and will be a valuable textbook reference for graduate students and for professionals engaged in SQUID research and engineering. It will also be of use to specialists in multiple fields of practical SQUID applications, from human brain research and heart diagnostics to airplane and nuclear

  16. Vortex electronis and squids

    CERN Document Server

    2003-01-01

    Understanding the nature of vortices in high-Tc superconductors is a crucial subject for research on superconductive electronics, especially for superconducting interference devices (SQUIDs), it is also a fundamental problem in condensed-matter physics. Recent technological progress in methods for both direct and indirect observation of vortices, e.g. scanning SQUID, terahertz imaging, and microwave excitation, has led to new insights into vortex physics, the dynamic behavior of vortices in junctions and related questions of noise. This book presents the current status of research activity and provides new information on the applications of SQUIDs, including magnetocardiography, immunoassays, and laser-SQUID microscopes, all of which are close to being commercially available.

  17. Market Squid Population Dynamics

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains population dynamics data on paralarvae, juvenile and adult market squid collected off California and the US Pacific Northwest. These data were...

  18. Market Squid Ecology Dataset

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains ecological information collected on the major adult spawning and juvenile habitats of market squid off California and the US Pacific Northwest....

  19. rf SQUID metamaterials

    OpenAIRE

    Lazarides, N.; Tsironis, G. P.

    2007-01-01

    An rf superconducting quantum interference device (SQUID) array in an alternating magnetic field is investigated with respect to its effective magnetic permeability, within the effective medium approximation. This system acts as an inherently nonlinear magnetic metamaterial, leading to negative magnetic response, and thus negative permeability, above the resonance frequency of the individual SQUIDs. Moreover, the permeability exhibits oscillatory behavior at low field intensities, allowing it...

  20. SQUIDs - quo vadis?

    Energy Technology Data Exchange (ETDEWEB)

    Koch, H. [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany)], E-mail: hans.koch@ptb.de

    2008-09-15

    For many decades R and D on superconducting quantum infererence devices (SQUIDs) has resulted in numerous and very diverse applications. However the commercial success of these applications is still marginal. This contribution analyses the reasons and discusses possible measures to improve this situation particularly for the application of multichannel SQUID systems for magnetoencephalography (MEG) and magnetocardiograpphy (MCG). The possible impact of combining low field magnetresonance imaging (lfMRI) with MEG and/or MCG is considered as well.

  1. Molecular inference of phylogenetic relationships among Decapodiformes (Mollusca: Cephalopoda) with special focus on the squid order Oegopsida.

    Science.gov (United States)

    Lindgren, Annie R

    2010-07-01

    Squids, cuttlefish and bobtail squids comprise the molluscan superorder Decapodiformes (Mollusca: Cephalopoda). Although these animals exemplify the morphological and ecological diversity seen in Cephalopoda, no previous study has focused resolving decapodiform relationships, particularly within Oegopsida, a large order comprised of pelagic squid. To further clarify the phylogenetic history of Decapodiformes, and Oegopsida in particular, molecular data for five genes (18S rRNA, 28S rRNA, Histone H3, 16S rRNA, COI) was collected for 90 taxa representing all major lineages and families and evaluated using parsimony, likelihood, and Bayesian analysis. Although ordinal relationships were sensitive to analytical method, several conclusions can be inferred: the pelagic order Myopsida is closely related to the benthic sepioids, whose relationships were ambiguous, and Bathyteuthoidea is distinct from Oegopsida. Within Oegopsida several clades are consistently recovered, some with previous morphological support (e.g. chiroteuthid, lepidoteuthid, histioteuthid families) while others suggest novel relationships (e.g. Architeuthidae+Neoteuthidae). This study, with its broad coverage of taxa, provides the first in-depth analysis of Decapodiformes with special focus on the morphologically and biogeographically diverse Oegopsida, confirms several sister-taxon relationships, and provides new hypotheses of cephalopod evolution in the open ocean.

  2. Dispersive nanoSQUID magnetometry

    Science.gov (United States)

    Levenson-Falk, E. M.; Antler, N.; Siddiqi, I.

    2016-11-01

    We describe the theory and implementation of a dispersive magnetometer based on an aluminum nanoSQUID. The nanoSQUID consists of a superconducting loop interrupted by two variable-thickness weak-link nanobridge Josephson junctions. When the nanoSQUID is placed in parallel with a lumped-element capacitor, it acts as the inductive element in a resonant tank circuit. By performing microwave reflectometry on the circuit, the SQUID inductance can be measured, providing a sensitive meter of the flux threading the SQUID loop. In this review we provide the theoretical basis for the device, describe design and operation considerations, and present characterization results on several devices.

  3. The Microwave SQUID Multiplexer

    Science.gov (United States)

    Mates, John Arthur Benson

    2011-12-01

    This thesis describes a multiplexer of Superconducting Quantum Interference Devices (SQUIDs) with low-noise, ultra-low power dissipation, and great scalability. The multiplexer circuit measures the magnetic flux in a large number of unshunted rf SQUIDs by coupling each SQUID to a superconducting microwave resonator tuned to a unique resonance frequency and driving the resonators from a common feedline. A superposition of microwave tones measures each SQUID simultaneously using only two coaxial cables between the cryogenic device and room temperature. This multiplexer will enable the instrumentation of arrays with hundreds of thousands of low-temperature detectors for new applications in cosmology, materials analysis, and nuclear non-proliferation. The driving application of the Microwave SQUID Multiplexer is the readout of large arrays of superconducting transition-edge sensors, by some figures of merit the most sensitive detectors of electromagnetic signals over a span of more than nine orders of magnitude in energy, from 40 GHz microwaves to 200 keV gamma rays. Modern transition-edge sensors have noise-equivalent power as low as 10-20 W / Hz1/2 and energy resolution as good as 2 eV at 6 keV. These per-pixel sensitivities approach theoretical limits set by the underlying signals, motivating a rapid increase in pixel count to access new science. Compelling applications, like the non-destructive assay of nuclear material for treaty verification or the search for primordial gravity waves from inflation use arrays of these detectors to increase collection area or tile a focal plane. We developed three generations of SQUID multiplexers, optimizing the first for flux noise 0.17 muPhi0 / Hz1/2, the second for input current noise 19 pA / Hz1/2, and the last for practical multiplexing of large arrays of cosmic microwave background polarimeters based on transition-edge sensors. Using the last design we demonstrated multiplexed readout of prototype polarimeters with the

  4. SQUIDs: microscopes and nondestructive evaluation

    Science.gov (United States)

    Mück, Michael

    2005-03-01

    SQUIDs (Superconducting Quantum Interference Devices) are magnetic field sensores with unsurpassed sensitivity. They are amazingly versatile, being able to measure all physical quantities which can be converted to magnetic flux. They are routinely fabricated in thin film technology from two classes of superconducting materials: high-temperature superconductors (HTS) which are usually cooled to 77 K, and low-temperature superconductors (LTS), which have to be cooled to 4.2 K. SQUIDs have many applications, two of which shall be discussed in this paper. In SQUID microscopy, a SQUID scans a sample, which preferrably is at room temperature, and measures the two-dimensional magnetic field distribution at the surface of the sample. In order to achieve a relatively high spatial resolution, the stand-off distance between the sample and the SQUID is made as small as possible. SQUIDs show also promising results in the field of nondestructive testing of various materials. For example, ferromagnetic impurities in stainless steel formed by aging processes in the material can be detected with high probability, and cracks in conducting materials, for example aircraft parts, can be located using eddy current methods. Especially for the case of thick, highly conductive, or ferromagnetic materials, as well as sintered materials, it can be shown that a SQUID-based NDE system exhibits a much higher sensitivity compared to conventional eddy current NDE and ultrasonic testing.

  5. SQUID-based measuring systems

    Indian Academy of Sciences (India)

    M P Janawadkar; R Baskaran; R Nagendran; K Gireesan; N Harishkumar; Rita Saha; L S Vaidhyanathan; J Jayapandian; Y Hariharan; T S Radhakrishnan

    2002-05-01

    A program has been developed and initiated at the Indira Gandhi Centre for Atomic Research (IGCAR) for the utilization of SQUID sensors in various application areas. DC SQUID sensors based on Nb–AlO–Nb Josephson junctions have been designed and developed inhouse along with associated flux-locked loop (FLL) electronics. A compact low field SQUID magnetometer insertible in a liquid helium storage dewar has also been developed inhouse and is in use. Efforts to build a high field SQUID magnetometer, SQUID-DAC system, are in progress. A planar gradiometric DC SQUID sensor for non-destructive evaluation (NDE) application to be used in relatively unshielded environment has been designed and developed. An easily portable NDE cryostat with a small lift-off distance, to be used in external locations has been designed and tested. The magnetic field produced by a given two-dimensional current density distribution is inverted using the Fourier transform technique.

  6. Squid rocket science: How squid launch into air

    Science.gov (United States)

    O'Dor, Ron; Stewart, Julia; Gilly, William; Payne, John; Borges, Teresa Cerveira; Thys, Tierney

    2013-10-01

    Squid not only swim, they can also fly like rockets, accelerating through the air by forcefully expelling water out of their mantles. Using available lab and field data from four squid species, Sthenoteuthis pteropus, Dosidicus gigas, Illex illecebrosus and Loligo opalescens, including sixteen remarkable photographs of flying S. pteropus off the coast of Brazil, we compared the cost of transport in both water and air and discussed methods of maximizing power output through funnel and mantle constriction. Additionally we found that fin flaps develop at approximately the same size range as flight behaviors in these squids, consistent with previous hypotheses that flaps could function as ailerons whilst aloft. S. pteropus acceleration in air (265 body lengths [BL]/s2; 24.5m/s2) was found to exceed that in water (79BL/s2) three-fold based on estimated mantle length from still photos. Velocities in air (37BL/s; 3.4m/s) exceed those in water (11BL/s) almost four-fold. Given the obvious advantages of this extreme mode of transport, squid flight may in fact be more common than previously thought and potentially employed to reduce migration cost in addition to predation avoidance. Clearly squid flight, the role of fin flaps and funnel, and the energetic benefits are worthy of extended investigation.

  7. Understanding the Role of Host Hemocytes in a Squid/Vibrio Symbiosis Using Transcriptomics and Proteomics

    Directory of Open Access Journals (Sweden)

    Andrew J. Collins

    2012-05-01

    Full Text Available The symbiosis between the squid, Euprymna scolopes, and the bacterium, Vibrio fischeri, serves as a model for understanding interactions between beneficial bacteria and animal hosts. The establishment and maintenance of the association is highly specific and depends on the selection of V. fischeri and exclusion of non-symbiotic bacteria from the environment. Current evidence suggests that the host’s cellular innate immune system, in the form of macrophage-like hemocytes, helps to mediate host tolerance of V. fischeri. To begin to understand the role of hemocytes in this association, we analyzed these cells by high-throughput 454 transcriptomic and liquid chromatography/ tandem mass spectrometry (LC-MS/MS proteomic analyses. 454 high-throughput sequencing produced 650,686 reads totaling 279.9 Mb while LC-MS/MS analyses of circulating hemocytes putatively identified 702 unique proteins. Several receptors involved with the recognition of microbial associated molecular patterns (MAMPs were identified. Among these was a complete open reading frame (ORF to a putative peptidoglycan recognition protein (EsPGRP5 that has conserved residues for amidase activity. Assembly of the hemocyte transcriptome showed EsPGRP5 had high coverage, suggesting it is among the 5% most abundant transcripts in circulating hemocytes. Other transcripts and proteins identified included members of the conserved NFκB signaling pathway, putative members of the complement pathway, the carbohydrate binding protein galectin, and cephalotoxin. Quantitative PCR of complement-related genes, cephalotoxin, EsPGRP5, and a nitric oxide synthase showed differential expression in circulating hemocytes isolated from adult squid with colonized light organs compared to those for which the symbionts were removed. These data suggest that the presence of the symbiont influences gene expression of the cellular innate immune system of the host.

  8. SQUID holder with high magnetic shielding

    Science.gov (United States)

    Rigby, K. W.; Marek, D.; Chui, T. C. P.

    1990-01-01

    A SQUID holder designed for high magnetic shielding is discussed. It is shown how to estimate the attenuation of the magnetic field from the normal magnetic modes for an approximate geometry. The estimate agrees satisfactorily with the attenuation measured with a commercial RF SQUID installed in the holder. The holder attenuates external magnetic fields by more than 10 to the 9th at the SQUID input. With the SQUID input shorted, the response to external fields is 0.00001 Phi(0)/G.

  9. A series array of dc SQUIDs

    Energy Technology Data Exchange (ETDEWEB)

    Welty, R.P. (Colorado Univ., Boulder, CO (United States). Dept. of Electrical Engineering); Martinis, J.M. (Geraghty and Miller, Inc., Reston, VA (United States))

    1991-03-01

    This paper reports on a series array of 100 dc SQUIDs using trilayer Nb-AlO{sub x}-Nb junctions. The SQUIDs are modulated with a common flux bias line and produce an output voltage swing of several millivolts across the array. The large output voltage will allow direct connection to room temperature electronics without the transformer coupling and resulting frequency limitations commonly associated with dc SQUID amplifiers. The authors measured a bandwidth of dc to at least 175 MHz for a 100-SQUID array. The series array will be used as the output stage for a multistage integrated SQUID amplifier.

  10. Cold SQUIDs and hot samples

    Energy Technology Data Exchange (ETDEWEB)

    Lee, T.S.C. [Univ. of California, Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley national Lab., CA (United States). Materials Sciences Div.

    1997-05-01

    Low transition temperature (low-{Tc}) and high-{Tc} Superconducting QUantum Interference Devices (SQUIDs) have been used to perform high-resolution magnetic measurements on samples whose temperatures are much higher than the operating temperatures of the devices. Part 1 of this work focuses on measurements of the rigidity of flux vortices in high-{Tc} superconductors using two low-{Tc} SQUIDs, one on either side of a thermally-insulated sample. The correlation between the signals of the SQUIDs is a direct measure of the extent of correlation between the movements of opposite ends of vortices. These measurements were conducted under the previously-unexplored experimental conditions of nominally-zero applied magnetic field, such that vortex-vortex interactions were unimportant, and with zero external current. At specific temperatures, the authors observed highly-correlated noise sources, suggesting that the vortices moved as rigid rods. At other temperatures, the noise was mostly uncorrelated, suggesting that the relevant vortices were pinned at more than one point along their length. Part 2 describes the design, construction, performance, and applications of a scanning high-{Tc} SQUID microscope optimized for imaging room-temperature objects with very high spatial resolution and magnetic source sensitivity.

  11. Paleomagnetism with the SQUID Microscope

    Science.gov (United States)

    Weiss, B. P.; Baudenbacher, F. J.; Wikswo, J. P.; Kirschvink, J. L.

    2002-05-01

    Rocks should preserve stable remanent magnetizations with useful directional and intensity information at levels down to ~10-15 Am2, about 1000 times below that of the noise level on today's best superconducting moment magnetometers. As a result, a more sensitive magnetometer could dramatically expand the range and variety of rock types amenable to paleomagnetic analysis. Just such an instrument is now on the horizon: the superconducting quantum interference device (SQUID) Microscope, designed by F. Baudenbacher and J. Wikswo of Vanderbilt University. The SQUID Microscope makes a map of the vertical component of the magnetic field above the surface of a sample held at room temperature and pressure. It achieves this with a spatial resolution of 250 μ m and a moment sensitivity 10,000 times that of the most recent 2G Enterprises Superconducting Rock Magnetometer (2G SRM). It can therefore provide data with a resolution comparable with that of other common petrographic techniques such as optical and electron microscopy. A major reason that the SQUID Microscope has such high sensitivity and resolution compared to the 2G SRM is that it has a much smaller pickup coil. Smaller coils are more sensitive to dipoles because they encompass less of the sample's fringing fields oriented in the opposite sense to its magnetization. Smaller coils also encompass a smaller area above the sample and so also provide higher spatial resolution. Our initial collaborative work on 30-μ m thin sections of Martian meteorite ALH84001 has already demonstrated that SQUID Microscopy will enable a whole a new class of paleomagnetic analyses. Conglomerate, baked contact, and fold tests can be performed on extremely small spatial scales, vastly expanding the utility of these critical geological field tests of magnetic stability. A suite of rock-magnetic and paleomagnetic experiments can be done on individual grains in standard petrographic thin sections at very high rates, allowing the observed

  12. Dc SQUIDs with asymmetric shunt resistors

    Energy Technology Data Exchange (ETDEWEB)

    Rudolph, Matthias; Nagel, Joachim; Kemmler, Matthias; Koelle, Dieter; Kleiner, Reinhold [Physikalisches Institut - Experimentalphysik II and Center for Collective Quantum Phenomena in LISAplus, Universitaet Tuebingen (Germany); Meckbach, Johannes Maximilian; Ilin, Konstantin; Siegel, Michael [Institut fuer Mikro- und Nanoelektronische Systeme, Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2013-07-01

    We have investigated asymmetrically shunted Nb/Al-AlO{sub x}/Nb dc SQUIDs. Simulations based on the coupled Langevin equations predict that the optimum energy resolution ε, and thus also the noise performance of such an asymmetric SQUID, can be 3-4 times better than that of its symmetric counterpart. While keeping the total resistance R identical to a comparable symmetric SQUID with R{sup -1} = R{sub 1}{sup -1} + R{sub 2}{sup -1}, we shunted only one of the two Josephson junctions with R = R{sub 1,2}/2. Both types of SQUIDs were characterized with respect to their transport and noise properties at temperature T = 4.2 K, and we compared the experimental results with numerical simulations. Experiments yielded ε ∼ 32 ℎ for an asymmetric SQUID with an inductance L = 22 pH, whereas a comparable symmetric device achieved ε = 110 ℎ.

  13. Low field electron paramagnetic resonance imaging with SQUID detection

    Science.gov (United States)

    Hahn, Inseob (Inventor); Day, Peter K. (Inventor); Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Cohen, Mark S. (Inventor)

    2012-01-01

    In one embodiment, a flux transformer with a gradiometer pickup coil is magnetically coupled to a SQUID, and a SQUID array amplifier comprising a plurality of SQUIDs, connected in series, is magnetically coupled to the output of the SQUID. Other embodiments are described and claimed.

  14. A SQUID series array dc current sensor

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, J; Drung, D [Physikalisch-Technische Bundesanstalt (PTB), Abbestrasse 2-12, D-10587 Berlin (Germany)], E-mail: joern.beyer@ptb.de, E-mail: dietmar.drung@ptb.de

    2008-09-15

    Superconducting quantum interference device (SQUID) sensors are used to sense changes in various physical quantities, which can be transformed into changes in the magnetic flux threading the SQUID loop. We have developed a novel SQUID array dc current sensor. The device is based on a series array of identical dc SQUIDs. An input signal current to be measured is coupled tightly but non-uniformly to the SQUID array elements. The input signal coupling to the individual array elements is chosen such that a single-valued, non-periodic overall voltage response is obtained. Flux offsets in the individual SQUIDs which would compromise the sensor voltage response are avoided or can be compensated. We present simulations and experimental results on the SQUID Array for Dc (SQUAD) current sensor current sensor performance. A dc current resolution of <1 nA in a measurement bandwidth of 0-25 Hz is achieved for an input inductance of L{sub In}<3 nH.

  15. Aperture effects in squid jet propulsion.

    Science.gov (United States)

    Staaf, Danna J; Gilly, William F; Denny, Mark W

    2014-05-01

    Squid are the largest jet propellers in nature as adults, but as paralarvae they are some of the smallest, faced with the inherent inefficiency of jet propulsion at a low Reynolds number. In this study we describe the behavior and kinematics of locomotion in 1 mm paralarvae of Dosidicus gigas, the smallest squid yet studied. They swim with hop-and-sink behavior and can engage in fast jets by reducing the size of the mantle aperture during the contraction phase of a jetting cycle. We go on to explore the general effects of a variable mantle and funnel aperture in a theoretical model of jet propulsion scaled from the smallest (1 mm mantle length) to the largest (3 m) squid. Aperture reduction during mantle contraction increases propulsive efficiency at all squid sizes, although 1 mm squid still suffer from low efficiency (20%) because of a limited speed of contraction. Efficiency increases to a peak of 40% for 1 cm squid, then slowly declines. Squid larger than 6 cm must either reduce contraction speed or increase aperture size to maintain stress within maximal muscle tolerance. Ecological pressure to maintain maximum velocity may lead them to increase aperture size, which reduces efficiency. This effect might be ameliorated by nonaxial flow during the refill phase of the cycle. Our model's predictions highlight areas for future empirical work, and emphasize the existence of complex behavioral options for maximizing efficiency at both very small and large sizes.

  16. Review of SQUID Sensors for Measuring Magnetocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. H.; Kim, J. M.; Yu, K. K.; Kim, K.; Kwon, H. [Brain and Cognition Measurement Lab, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2011-08-15

    Measurement of magnetic signals generated from electric activity of myocardium provides useful information for the functional diagnosis of heart diseases. Key technical component of the magnetocardiography (MCG) technology is SQUID. To measure MCG signals with high signal-to-noise ratio, sensitive SQUID magnetic field sensors are needed. Present magnetic field sensors based on Nb SQUIDs have field sensitivity good enough to measure most of MCG signals. However, for accurate measurement of fine signal pattern or detection of local atrial fibrillation signals, we may need higher field sensitivity. In addition to field sensitivity, economic aspect of the SQUID system is also important. To simplify the SQUID readout electronics, the output voltage or flux-to-voltage transfer of SQUID should be large enough so that direct measurement of SQUID output can be done using room-temperature preamplifiers. Double relaxation oscillation SQUID (DROS), having about 10 times larger flux-to-voltage transfers than those of DC-SQUIDs, was shown to be a good choice to make the electronics compact. For effective cancellation of external noise inside a thin economic shielded room, first-order axial gradiometer with high balance, simple structure and long-baseline is needed. We developed a technology to make the axial gradiometer compact using direct bonding of superconductive wires between pickup coil and input coil. Conventional insert has mechanical support to hold the gradiometer array, and the dewar neck has equal diameter with the dewar bottom. Boiling of the liquid He can generate mechanical vibrations in the gradiometer array due to mechanical connection structure. Elimination of the mechanical support, and direct mounting of the gradiometer array into the dewar bottom can reduce the dewar neck diameter, resulting in the reduction of liquid He consumption.

  17. Measurement of a SQUID metamaterial

    Science.gov (United States)

    Zhang, Daimeng; Trepanier, Melissa; Anlage, Steven

    2013-03-01

    We report experimental results on a new type of superconducting metamaterial consisting of arrays of RF SQUIDs operating in the microwave frequency range with tunable properties (S parameters, effective permeability, effective permittivity, etc.). DC magnetic field is applied to bias the sample and to vary the Josephson inductance, thus tuning the resonant frequency over a multi-GHz range. The experiment is done in a magnetic-shielded cryostat where we examine the temperature, RF-field, and DC-field dependence of S parameters of this superconducting metamaterial. We also perform a cryogenic calibration to eliminate the effects of transmission lines on our results. From the calibrated S-matrix of this metamaterial, we are able to extract the effective permeability and its response to various stimuli. This work is supported by the NSF-GOALI program through grant # ECCS-1158644, and CNAM.

  18. Squid based beam current meter

    Energy Technology Data Exchange (ETDEWEB)

    Kuchnir, M.

    1983-11-25

    A SQUID based beam current meter has the capability of measuring the current of a beam with as little as 30 x 155 antiprotons (with a signal to noise ratio of 2). If low noise dc current is used to cancel most of the beam or an up-down counter is used to count auto-resets this sensitivity will be available at any time in the acumulation process. This current meter will therefore be a unique diagnostic tool for optimizing the performance of several Tev I components. Besides requiring liquid helium it seems that its only drawback is not to follow with the above sensitivity a sudden beam change larger than 16 ..mu..A, something that could be done using a second one in a less sensitive configuration.

  19. North Pacific High Seas Squid Jig Logbook

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a federally mandated logbook program high seas squid jig fishing, and it is required to be mailed in to PIFSC after a fishing trip. Fishing occurs in the...

  20. YBCO SQUIDs with unconventional current phase relation

    Energy Technology Data Exchange (ETDEWEB)

    Bauch, T. [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-41296 Goeteborg (Sweden)], E-mail: Thilo.bauch@mc2.chalmers.se; Johansson, J.; Cedergren, K. [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-41296 Goeteborg (Sweden); Lindstroem, T. [National Physical Laboratory, Teddington, Middlesex TW11 0LW (United Kingdom); Lombardi, F. [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-41296 Goeteborg (Sweden)

    2007-10-01

    We have studied the dynamics of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) dc sperconducting quantum interference devices (SQUIDs) characterized by an unconventional Josephson current phase relation (CPR). We have focused on SQUID configurations with Josephson junctions where the lobe of the order parameter in one electrode is facing a node in the other electrode. This order parameter arrangement should enhance the appearance of a sin(2{phi}) term in the CPR. The response of the critical current of the dc SQUID, under the effect of an external magnetic field, has been measured in temperature, down to 20 mK. Our experimental data have been compared with numerical simulations of the SQUIDs dynamics by considering a CPR of a single junction of the form I({phi}) = I{sup I} sin({phi}) - I{sup II} sin(2{phi}) where I{sup I} and I{sup II} are, respectively, the first and second harmonic component. In our devices the values of the sin(2{phi}) term are such that the fundamental state of the SQUID is naturally double degenerate. This is of great relevance for applications of d-wave SQUIDs in quantum information processing.

  1. Development of Biomimetic Squid-Inspired Suckers

    Institute of Scientific and Technical Information of China (English)

    Jinping Hou; Edward Wright; Richard H. C. Bonser; George Jeronimidis

    2012-01-01

    Biomechanical properties of squid suckers were studied to provide inspiration for the development of sucker artefacts for a robotic octopus.Mechanical support of the rings found inside squid suckers was studied by bending tests.Tensile tests were carried out to study the maximum possible sucking force produced by squid suckers based on the strength of sucker stalks,normalized by the sucking areas.The squid suckers were also directly tested to obtain sucking forces by a special testing arrangement.Inspired by the squid suckers,three types of sucker artefacts were developed for the arm skin of an octopus inspired robot.The first sucker artefact made of knitted nylon sheet reinforced silicone rubber has the same shape as the squid suckers.Like real squid suckers,this type of artefact also has a stalk that is connected to the arm skin and a ring to give radial support.The second design is a straight cylindrical structure with uniform wall thickness made of silicone rubber.One end of the cylinder is directly connected to the arm skin and the other end is open.The final design of the sucker has a cylindrical base and a concave meniscus top.The meniscus was formed naturally using the surface tension of silicone gel,which leads to a higher level of the liquid around the edge of a container.The wall thickness decreases towards the tip of the sucker opening.Sucking forces of all three types of sucker artefacts were measured.Advantages and disadvantages of each sucker type were discussed.The final design of suckers has been implemented to the arm skin prototypes.

  2. Microstrip SQUID amplifiers for quantum information science

    Science.gov (United States)

    Defeo, M. P.; Plourde, B. L. T.

    2012-02-01

    Recent progress in SQUID amplifiers suggests that these devices might approach quantum-limited sensitivity in the microwave range, thus making them a viable option for measurement of superconducting quantum systems. In the microstrip SQUID amplifier configuration, gains of around 20dB are possible at frequencies of several hundred MHz, and the gain is limited by the maximum voltage modulation available from the SQUID. One route for increasing the voltage modulation involves using larger resistive shunts, however maintaining non-hysteretic device operation requires smaller junction capacitances than is possible with conventional photolithographically patterned junctions. Operating at higher frequencies requires a shorter input coil which reduces mutual inductance between the coil and washer and therefore gain. We have fabricated microstrip SQUID amplifiers using submicron Al-AlOx-Al junctions and large shunts. The input coil and SQUID washer are optimized for producing high gain at frequencies in the gigahertz range. Recent measurements of gain and noise temperature will be discussed as well as demonstrations of these devices as a first stage of amplification for a superconducting system

  3. The use of (double) relaxation oscillation SQUIDs as a sensor

    NARCIS (Netherlands)

    Duuren, van M.J.; Brons, G.C.S.; Kattouw, H.; Flokstra, J.; Rogalla, H.

    1997-01-01

    Relaxation Oscillation SQUIDs (ROSs) and Double Relaxation Oscillation SQUIDs (DROSs) are based on relaxation oscillations that are induced in hysteretic dc SQUIDs by an external L-R shunt. The relaxation frequency of a ROS varies with the applied flux Φ, whereas the output of a DROS is a dc voltage

  4. Experiments with SQUID-based metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Butz, Susanne; Jung, Philipp [Physikalisches Institut, Karlsruher Institut fuer Technologie, 76131 Karlsruhe (Germany); Shitov, Sergey V. [Institute of Radio Engenieering and Electronics (IREE RAS), Moscow 125009 (Russian Federation); National University of Science and Technology MISIS, Moscow 119049 (Russian Federation); Ustinov, Alexey V. [Physikalisches Institut, Karlsruher Institut fuer Technologie, 76131 Karlsruhe (Germany); National University of Science and Technology MISIS, Moscow 119049 (Russian Federation)

    2012-07-01

    Metamaterials consist of elements that are artificially created to obtain a specific, predetermined interaction with an electromagnetic wave. The size of individual elements is much smaller than the wavelength of the incoming radiation. Conventionally, split ring resonators are used to interact with the magnetic field component of the wave. The interaction with the electric component is realized by thin metallic wires. We designed a Josephson junction based metamaterial where the split ring resonators are replaced by rf-SQUIDs. The benefits compared to conventional metamaterials are that the losses are reduced and that the inductance of the Josephson junction can be tuned by an external magnetic field. This, in turn, changes the resonance frequency of the metamaterial, making the magnetic permeability, μ{sub r}, tunable in situ. We will report on first experiments investigating such a SQUID metamaterial composed of a coplanar waveguide coupled to a one-dimensional array of rf-SQUIDs. The experimental results are compared with numerical simulations.

  5. DC SQUIDS with planar input coils

    Energy Technology Data Exchange (ETDEWEB)

    Pegrum, C.M.; Donaldson, G.B.; Hutson, D.; Tugwell, A.

    1985-03-01

    We describe the key parts of our recent work to develop a planar thin-film DC SQUID with a closely-coupled spiral input coil. Our aim has been to make a device that is superior to present RF SQUID sensors in terms of sensitivity and long-term reliability. To be compatible with an RF SQUID the inductance of the input coils must be relatively large, typically 2..mu..H, and the input noise current in the white noise region should be below 10pA Hz /SUP -1/2/ . A low level of 1/f noise is also necessary for many applications and should be achieved without the use of complex noisecancelling circuitry. Our devices meet these criteria. We include a description of work on window and edge junction fabrication using ion beam cleaning, thermal oxidation and RF plasma processing.

  6. Practical dc SQUID system: Devices and electronics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guofeng [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ (Germany); Zhang, Yi, E-mail: y.zhang@fz-juelich.de [Peter Grünberg Institute (PGI-8), Forschungszentrum Jülich (FZJ), D-52425 Jülich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ (Germany); Hong, Tao; Wang, Hai [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ (Germany); University of Chinese Academy of Sciences, Beijing 100049 (China); Krause, Hans-Joachim [Peter Grünberg Institute (PGI-8), Forschungszentrum Jülich (FZJ), D-52425 Jülich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ (Germany); Xie, Xiaoming [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ (Germany)

    2015-11-15

    Highlights: • The current noise contribution in direct readout scheme for dc SQUID was analyzed. • A current feedback circuit for suppressing the current noise was introduced. • Two criteria to measure the suppression factor were introduced. • A practical SQUID system with acceptable noise performance was suggested. - Abstract: In order to set up a liquid helium-cooled practical dc SQUID system with acceptable noise figure, we employ a weakly damped dc SQUID with a large flux-to-voltage transfer coefficient ∂V/∂Φ in a direct readout scheme (DRS) without flux modulation. Two preamplifiers are utilized: (1) AD 797 for a so-called “single chip readout electronics” (SCRE); (2) 6 parallel-connected bipolar transistors (PCBT). The latter reduces the preamplifier voltage noise V{sub n} but increases its current noise I{sub n}, which plays a leading role in the system low-frequency noise. We introduce a current feedback circuit (CFC) consisting of an inductor L{sub i} coupled to the SQUID with mutual inductance M{sub i} to improve the noise performance. In this work, the preamplifier I{sub n} contribution and CFC are analyzed. To evaluate the I{sub n} suppression with CFC, two criteria are presented. Furthermore, we establish a dimensionless parameter ξ to describe CFC quantitatively. The system noise is compared with and without CFC using the two preamplifiers. For a dc SQUID with a loop inductance of 350 pH, an intrinsic noise of about 5 μΦ{sub 0}/√Hz and a corner frequency at 2 Hz are measured using PCBT with CFC.

  7. Magnetism in SQUIDs at Millikelvin Temperatures

    Science.gov (United States)

    Sendelbach, S.; Hover, D.; Kittel, A.; Mück, M.; Martinis, John M.; McDermott, R.

    2008-06-01

    We have characterized the temperature dependence of the flux threading dc SQUIDs cooled to millikelvin temperatures. The flux increases as 1/T as temperature is lowered; moreover, the flux change is proportional to the density of trapped vortices. The data are compatible with the thermal polarization of surface spins in the trapped fields of the vortices. In the absence of trapped flux, we observe evidence of spin-glass freezing at low temperature. These results suggest an explanation for the universal 1/f flux noise in SQUIDs and superconducting qubits.

  8. Negative response and intrinsic localization in rf SQUID metamaterials.

    Science.gov (United States)

    Tsironis, George; Lazarides, Nikolaos; Eleftheriou, Maria

    2008-03-01

    A periodic array of rf SQUIDs in an alternating magnetic field acts as an inherently nonlinear magnetic metamaterial, due to the nonlinearity of the Josephson element and the resonant properties of the SQUIDs themselves. Neighboring SQUIDs are weakly coupled due to magnetic dipole-dipole interaction through their mutual inductances, allowing an effective medium description if the wavelength of the applied field is much larger than the array period. We found that SQUID arrays can provide negative magnetic response, and thus negative permeability, above the resonance frequency of the individual SQUIDs. Moreover, that response can be tuned by the applied flux. Dissipative SQUID arrays, modeled as discrete networks, support nonlinear excitations in the form of intrinsic localized modes (discrete breathers). We found that dissipative discrete breathers exist in both one- and two-dimensional SQUID arrays. Furthermore, those breathers alter locally the magnetic response of an array from paramagnetic to diamagnetic or vice versa.

  9. Microwave SQUID A/D Converters.

    Science.gov (United States)

    1980-06-05

    using Josephson junction SQUID circuito . The projected perfor- * mance envisions an aperture time limit of 0. 25 o i 1 75Dsec with the Pb alloy junction...2n 7. Pulse Shape for Single Cell with Three Values of Capacitance (e - RC /L) and = ir, I0 = 0. 8 5 Ic ........... 5 8. Pulse Shape for Single Cell

  10. Digital SQUIDs based on Smart DROS

    NARCIS (Netherlands)

    Podt, M.; Keizer, D.; Flokstra, J.; Rogalla, H.

    1999-01-01

    A Double Relaxation Oscillation SQUID (DROS) with the complete flux locked loop (FLL) circuitry on one single chip, a Smart DROS, has been realized. A superconducting storage loop interrupted by two write gates to add or extract flux quanta acts as an integrator that supplies the feedback flux to th

  11. Experiments with double-SQUID qubits

    Energy Technology Data Exchange (ETDEWEB)

    Doerling, Bernhard; Poletto, Stefano; Ustinov, Alexey V. [Karlsruher Institut fuer Technologie (Germany); Castellano, Maria Gabriella; Chiarello, Fabio [Instituto Fotonica e Nanotecnologie, CNR, Roma (Italy)

    2010-07-01

    A double-SQUID qubit (flash-qubit) allows the manipulation of quantum states by very short pulses of magnetic flux, without using microwaves. It consists of an rf-SQUID with a dc-SQUID replacing the single Josephson junction. The energy potential profile is controllable by dc bias fluxes threading the two loops. The initial qubit state in a double well is prepared by applying a dc flux pulse to one loop, thereby tilting the double well so that only one of the two states remains stable. To manipulate the state of the qubit a dc flux pulse is applied to the other loop to change the potential into a single well, where coherent Larmor oscillations between the two lowest eigenstates take place. Reading out the state is once again performed in the double well situation, where our readout dc-SQUID is able to discriminate between the two computational states due to their flux difference. We hope to present measurements done on a new sample, fabricated using shadow evaporation of aluminium and silicon nitride as the dielectric.

  12. One Period of Exploration with the Squid.

    Science.gov (United States)

    Bradley, James V.; Ng, Andrew

    1997-01-01

    Presents a lab that can be offered after students have learned the basic anatomy and physiology of the various phyla, the primary objective of which is to explore and apply their acquired knowledge to a new situation. Involves exploring the anatomy and life-style of the squid. (JRH)

  13. Choreography of the squid's "nuptial dance".

    Science.gov (United States)

    Sauer, W H; Roberts, M J; Lipinski, M R; Smale, M J; Hanlon, R T; Webber, D M; O'Dor, R K

    1997-04-01

    A mass spawning of squid resembles, at first glance, a chaotic "nuptial dance" (1). But for the first time, we have applied 3-D, radio-linked acoustic positioning (RAP) to this confusing process, and our early results now reveal a choreography that is, in fact, well organized in time and space. Remote tracking with RAP of individual Loligo vulgaris reynaudii off South Africa has provided insights into the daily sequence of behaviours that lead these animals to aggregate for sexual selection. Each dawn, the squid navigate for several kilometers, towards the shore, to small, well-defined zones near egg beds on the substrate. After several hours of circling above the egg beds, a pelagic, 3-D lek-like aggregation of large males forms: females are drawn in, and the aggregation condenses as the females and males pair, mate, and lay eggs. Smaller "sneaker males" remain on the periphery of the mating arena and, from this station, attempt extra-pair copulations (EPCs). The mating system of squids is thus unexpectedly complex, rivaling those of mammals and birds (2, 3). Commercial squid-jigging fishermen in South Africa have recently been attracted to the spawning grounds, and they have been successful. Moreover, their activities may be selective for large males. Thus, attention should be devoted to ensuring that such targeted fishing does not alter the characteristics of squid population genetics. Remote tracking and video observations, in combination with genetic analyses, may offer a new opportunity to monitor mating effort and reproductive success, and thus to manage the fishery.

  14. Laser-SQUID microscope for noncontact evaluation of solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Nakatani, Y., E-mail: nakatani@sup.ee.es.osaka-u.ac.jp [Osaka University, 1-3, Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Hayashi, T. [Sendai National College of Technology, 4-16-1, Ayashityuou, Aoba-ku, Sendai, Miyagi 989-3128 (Japan); Itozaki, H. [Osaka University, 1-3, Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)

    2011-11-15

    A polycrystalline solar cell was investigated by the laser-SQUID microscope without contact to the surface of the solar cell. The laser-SQUID microscope image of the solar cell was similar to the laser-beam-induced current image. The laser-SQUID microscope images varied when the needle and the SQUID were shifted in the x- and y-directions from the center of a laser spot. The laser-SQUID microscopy has the possibility of estimation of the photocurrent direction. A polycrystalline solar cell with several grains was investigated by the laser-SQUID (Superconducting QUantum Interference Device) microscope. The laser-SQUID microscopy detects the magnetic field generated by a photo-induced current. This technique enables nondestructive and noncontact evaluation of semiconductor samples. A needle made of high permeability material was used to transmit the magnetic field near the sample to the SQUID. The needle and the SQUID were shifted in the x- and y-directions from the center of a laser spot. The laser-SQUID microscope images varied with needle position. This indicated the possibility of current estimation using a laser-SQUID microscope. In this study the sample was also evaluated using Laser Beam Induced Current (LBIC) which is widely used for evaluation of the conversion efficiency distribution of solar cells. The laser-SQUID microscope image was compared with the LBIC image and was found to be similar. This result showed that laser-SQUID microscopy can be used for the electrical evaluation of solar cells without contact, and furthermore has the possibility of estimation of the photocurrent direction.

  15. SQUIDs for the characterization of magnetic nanoparticles; SQUIDs fuer die Charakterisierung magnetischer Nanoteilchen

    Energy Technology Data Exchange (ETDEWEB)

    Guillaume, Alexander

    2015-07-01

    Magnetic nanoparticles (MNP) are superparamagnetic particles with a core diameter in the nm-range. The MNPs have manifold properties which make them an interesting tool for various applications. Certain parameters, such as size or size distribution and structural properties, must be well known for these applications. In this work, the dynamic behavior of MNPs was investigated by magnetorelaxometry (MRX) at a temperature of 77 K. MRX is based on the alignment of the moment of individual MNPs in parallel to a large enough magnetization field. After switching of the field, the magnetization decays with a characteristic time constant. The measurement of the relaxation can e.g. be used to calculate the size distribution of a given MNP sample. Superconducting quantum interference devices (SQUID) based on the high-T{sub c} superconductor yttrium barium copper oxide (YBCO) were employed in this work as sensors for the magnetic field. The fabrication of the superconducting and isolating thin films was carried out by pulsed laser deposition (PLD) and optimized by methods of experimental design. Several types of directly coupled SQUIDs were fabricated from the thin films by optical lithography and argon ion etching. An existing MRX setup with fluxgates was modified to allow measurements with the directly coupled SQUIDs at 77 K. After the characterization of the system, MRX measurements were performed. The relaxation of an amount of approximately 100 billion MNPs was detected at a distance of 5 mm to the SQUID. In order to reduce the minimum detectable amount of MNPs and to minimize disturbances, a novel type of SQUID was developed, fabricated and characterized. A compensation factor of up to 195 was experimentally demonstrated with this self-compensating SQUID. MNP samples were prepared directly on the SQUID by electron beam lithography. Thereby, an amount of 167 MNPs could be detected. The limit for the measurement setup was evaluated as 58 MNPs. Finite element method (FEM

  16. Scanning SQUID microscopy for magnetic flux systems

    CERN Document Server

    Suzuki, J I; Hata, Y

    2003-01-01

    Recently, vortices confined into micro-scale superconductors with shapes like a disk, triangle, square, etc., have attracted much attention because of the quantum phase transition of the self-organized vortex arrangement occurring within such geometrical constraints. Such a transition can be observed using a scanning SQUID microscope with high spatial resolution. We have successfully improved spatial resolution by incorporating a microfabrication technique that reduces both the size of the pick-up coil of the micro DC-SQUID and the standoff distance between the pick-up coil and the sample surface. Using this microscope, we have studied vortex arrangements in micro-scale superconductors made of Nb and YBa sub 2 Cu sub 3 O sub 7 sub - subdelta films with various sizes and geometrical shapes. A peculiar oscillating behavior of diamagnetic magnetization corresponding to the particular vortex state was observed.

  17. Biomagnetism using SQUIDs: status and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Sternickel, Karsten [CardioMag Imaging, Inc., 450 Duane Avenue, Schenectady, NY 12304 (United States); Braginski, Alex I [Research Center Juelich, ISG-2, D-52425 Juelich (Germany)

    2006-03-15

    Biomagnetism involves the measurement and analysis of very weak local magnetic fields of living organisms and various organs in humans. Such fields can be of physiological origin or due to magnetic impurities or markers. This paper reviews existing and prospective applications of biomagnetism in clinical research and medical diagnostics. Currently, such applications require sensitive magnetic SQUID sensors and amplifiers. The practicality of biomagnetic methods depends especially on techniques for suppressing the dominant environmental electromagnetic noise, and on suitable nearly real-time data processing and interpretation methods. Of the many biomagnetic methods and applications, only the functional studies of the human brain (magnetoencephalography) and liver susceptometry are in clinical use, while functional diagnostics of the human heart (magnetocardiography) approaches the threshold of clinical acceptance. Particularly promising for the future is the ongoing research into low-field magnetic resonance anatomical imaging using SQUIDs.

  18. SQUID-based multichannel system for Magnetoencephalography

    CERN Document Server

    Rombetto, S; Vettoliere, A; Trebeschi, A; Rossi, R; Russo, M

    2013-01-01

    Here we present a multichannel system based on superconducting quantum interference devices (SQUIDs) for magnetoencephalography (MEG) measurements, developed and installed at Istituto di Cibernetica (ICIB) in Naples. This MEG system, consists of 163 full integrated SQUID magnetometers, 154 channels and 9 references, and has been designed to meet specifications concerning noise, dynamic range, slew rate and linearity through optimized design. The control electronics is located at room temperature and all the operations are performed inside a Magnetically Shielded Room (MSR). The system exhibits a magnetic white noise level of approximatively 5 fT/Hz1=2. This MEG system will be employed for both clinical and routine use. PACS numbers: 74.81.Fa, 85.25.Hv, 07.20.Mc, 85.25.Dq, 87.19.le, 87.85.Ng

  19. The Renormalization Effects in the Microstrip-SQUID Amplifier

    CERN Document Server

    Berman, G P; Tsifrinovich, V I

    2011-01-01

    The peculiarities of the microstrip-DC SQUID amplifier caused by the resonant structure of the input circuit are analyzed. It is shown that the mutual inductance, that couples the input circuit and the SQUID loop, depends on the frequency of electromagnetic field. The renormalization of the SQUID parameters due to the screening effect of the input circuit vanishes when the Josephson frequency is much greater than the signal frequency.

  20. Compartment-Specific Phosphorylation of Squid Neurofilaments.

    Science.gov (United States)

    Grant, Philip; Pant, Harish C

    2016-01-01

    Studies of the giant axon and synapse of third-order neurons in the squid stellate ganglion have provided a vast literature on neuronal physiology and axon transport. Large neuronal size also lends itself to comparative biochemical studies of cell body versus axon. These have focused on the regulation of synthesis, assembly, posttranslational modification and function of neuronal cytoskeletal proteins (microtubules (MTs) and neurofilaments (NFs)), the predominant proteins in axoplasm. These contribute to axonal organization, stability, transport, and impulse transmission responsible for rapid contractions of mantle muscles underlying jet propulsion. Studies of vertebrate NFs have established an extensive literature on NF structure, organization, and function; studies of squid NFs, however, have made it possible to compare compartment-specific regulation of NF synthesis, assembly, and function in soma versus axoplasm. Since NFs contain over 100 eligible sites for phosphorylation by protein kinases, the compartment-specific patterns of phosphorylation have been a primary focus of biochemical studies. We have learned that NF phosphorylation is tightly compartmentalized; extensive phosphorylation occurs only in the axonal compartment in squid and in vertebrate neurons. This extensive phosphorylation plays a key role in organizing NFs, in association with microtubules (MTs), into a stable, dynamic functional lattice that supports axon growth, diameter, impulse transmission, and synaptic activity. To understand how cytoskeletal phosphorylation is topographically regulated, the kinases and phosphatases, bound to NFs isolated from cell bodies and axoplasm, have also been studied.

  1. Low Field Squid MRI Devices, Components and Methods

    Science.gov (United States)

    Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Hahn, Inseob (Inventor)

    2014-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

  2. SQUIDs for the readout of metallic magnetic calorimeters

    Energy Technology Data Exchange (ETDEWEB)

    Ferring, Anna; Wegner, Mathias; Fleischmann, Andreas; Gastaldo, Loredana; Kempf, Sebastian; Enss, Christian [Kirchhoff-Institute for Physics, Heidelberg University (Germany)

    2015-07-01

    Superconducting quantum interference devices (SQUIDs) are the devices of choice to read out metallic magnetic calorimeters (MMCs). Here, the temperature change of the detector upon the absorption of an energetic particle is measured as a magnetization change of a paramagnetic temperature sensor that is situated in a weak magnetic field. Driven by the need for devices that allow for the readout of large-scale detector arrays with hundreds or even thousands of individual detectors as well as of single channel detectors with sub-eV energy resolution, we have recently started the development of low-T{sub c} current-sensing SQUIDs. In particular, we are developing cryogenic frequency-domain multiplexers based on non-hysteretic rf-SQUIDs for detector array readout as well as dc-SQUIDs for single channel detector readout. We discuss our SQUID designs and the performance of prototype SQUIDs. We particularly focus on the frequency and temperature dependence of the SQUID noise as well as the reliability of our SQUID fabrication process for Nb/Al-AlO{sub x}/Nb Josephson junctions. Additionally, we demonstrate experimentally that state-of-the-art MMCs can successfully be read out with our current devices. Finally, we discuss different strategies to improve the SQUID and detector performance aiming to reach sub-eV energy resolution for individual detectors as well as for detector arrays.

  3. Mobile high-T{sub c} DC SQUID magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    He, D.F.; Yoshizawa, M

    2003-05-01

    By optimizing the designing, we made a small size and low noise high-T{sub c} DC SQUID readout electronics with the modulation frequency of 80 kHz. The white flux noise was about 30 {mu}PHI{sub 0}/{radical}Hz when Sumitomo high-T{sub c} DC SQUID sensor was used. We also proved mobile high-T{sub c} DC SQUID magnetometer was feasible. By using a special compensation method, the SQUID magnetometer could keep locking when it swung about 20 degree sign in the earth field. Using this system and eddy-current nondestructive evaluation method, we successfully detected the defect in ferromagnetic material.

  4. SQUID magnetometry from nanometer to centimeter length scales

    Energy Technology Data Exchange (ETDEWEB)

    Hatridge, Michael J. [Univ. of California, Berkeley, CA (United States)

    2010-06-01

    The development of Superconducting QUantum Interference Device (SQUID)-based magnetometer for two applications, in vivo prepolarized, ultra-low field MRI of humans and dispersive readout of SQUIDs for micro- and nano-scale magnetometery, are the focus of this thesis.

  5. Directly coupled slotted high-Tc dc SQUIDs

    NARCIS (Netherlands)

    Jansman, A.B.M.; Izquierdo, M.; Flokstra, J.; Rogalla, H.

    1999-01-01

    A flux quantization model gives estimates for the effective area and washer inductance of slotted high-Tc dc SQUIDs. The inductance prediction has not been verified yet. Here, the theoretical dependence of washer inductance and effective area for four slotted SQUID types on the London penetration de

  6. Read-out electronics for DC squid magnetic measurements

    Science.gov (United States)

    Ganther, Jr., Kenneth R.; Snapp, Lowell D.

    2002-01-01

    Read-out electronics for DC SQUID sensor systems, the read-out electronics incorporating low Johnson noise radio-frequency flux-locked loop circuitry and digital signal processing algorithms in order to improve upon the prior art by a factor of at least ten, thereby alleviating problems caused by magnetic interference when operating DC SQUID sensor systems in magnetically unshielded environments.

  7. Reproductive biology in two species of deep-sea squids

    NARCIS (Netherlands)

    Laptikhovsky, V. V.; Arkhipkin, A. I.; Hoving, H. J. T.

    2007-01-01

    Deep-sea squids, Moroteuthis ingens and Gonatus antarcticus, were collected in the slope waters off the Falkland Islands and their reproductive systems preserved and investigated onshore. Changes in oocyte length-frequencies at maturation and spawning, and their fecundity were studied. These squids,

  8. Temperature dependence of DC SQUID magnetometer performances

    Energy Technology Data Exchange (ETDEWEB)

    Granata, C. E-mail: c.granata@cib.na.cnr.it; Monaco, A.; Di Russo, C.; Lissitski, M.P.; Russo, M

    2004-05-01

    We report experimental results on temperature dependence of the main characteristics of fully integrated DC SQUID magnetometers realized on niobium technology. At T=4.2 K the sensor shown a white magnetic field noise spectral density of 2.9 fT/Hz{sup 1/2}. A slow increase of the field noise (about 20%) was observed with increasing temperature up to 5 K, giving a considerable tolerance of the working temperature of niobium magnetometers in some innovative multichannel systems for magnetoencephalography.

  9. Feasibility of a stationary micro-SQUID

    CERN Document Server

    Berger, Jorge

    2016-01-01

    The standard operation of a dc SQUID leads to oscillatory electric fields that emit electromagnetic radiation and can change the state of the measured sample. A stationary SQUID could be advantageous when back action on the measured sample has to be avoided. We study a superconducting loop that encloses a magnetic flux, connected to a superconducting and to a normal electrode, when a fixed electric current between the electrodes flows through the loop. The considered circuit does not contain Josephson junctions. We find that in a very broad range of parameters the current flow converges to a stationary regime. The potential difference between the electrodes depends on the magnetic flux, so that measuring this voltage would provide information on the enclosed flux. The influence of thermal noise was estimated. The sizes of the voltage and of the power dissipation could be appropriate for the design of a practical fluxmeter. We found narrow ranges of flux at which the voltage varies sharply with the flux.

  10. Cross-linking chemistry of squid beak.

    Science.gov (United States)

    Miserez, Ali; Rubin, Daniel; Waite, J Herbert

    2010-12-03

    In stark contrast to most aggressive predators, Dosidicus gigas (jumbo squids) do not use minerals in their powerful mouthparts known as beaks. Their beaks instead consist of a highly sclerotized chitinous composite with incremental hydration from the tip to the base. We previously reported l-3,4-dihydroxyphenylalanine (dopa)-histidine (dopa-His) as an important covalent cross-link providing mechanical strengthening to the beak material. Here, we present a more complete characterization of the sclerotization chemistry and describe additional cross-links from D. gigas beak. All cross-links presented in this report share common building blocks, a family of di-, tri-, and tetra-histidine-catecholic adducts, that were separated by affinity chromatography and high performance liquid chromatography (HPLC) and identified by tandem mass spectroscopy and proton nuclear magnetic resonance ((1)H NMR). The data provide additional insights into the unusually high cross-link density found in mature beaks. Furthermore, we propose both a low molecular weight catechol, and peptidyl-dopa, to be sclerotization agents of squid beak. This appears to represent a new strategy for forming hard tissue in animals. The interplay between covalent cross-linking and dehydration on the graded properties of the beaks is discussed.

  11. Multistability and self-organization in disordered SQUID metamaterials

    Science.gov (United States)

    Lazarides, N.; Tsironis, G. P.

    2013-08-01

    Planar arrays of magnetoinductively coupled rf SQUIDs (Superconducting QUantum Interference Devices) belong to the emergent class of superconducting metamaterials that encompass the Josephson effect. These SQUID-based metamaterials acquire their electromagnetic properties from the resonant characteristics of their constitutive elements, i.e., the individual rf SQUIDs. In its simplest version, an rf SQUID consists of a superconducting ring interrupted by a Josephson junction. We investigate numerically the response of a two-dimensional rf SQUID metamaterial with respect to the driving frequency of an externally applied alternating magnetic field in the presence of disorder arising from critical current fluctuations of the Josephson elements; in effect, the resonance frequencies of individual SQUIDs are distributed randomly around a mean value. Bistability is observed in the current amplitude-frequency curves both in ordered and disordered SQUID metamaterials; moreover, bistability is favored by disorder through the improvement of synchronization between SQUID oscillators. Relatively weak disorder widens significantly the bistability region by helping the system to self-organize and leads to nearly homogeneous states that change smoothly with varying driving frequency. Also, the total current of the metamaterial is enhanced, compared with that of uncoupled SQUIDs, through the synergetic action of coupling and synchronization. The existence of simultaneously stable states that provide either high or low total current, allows the metamaterial to exhibit different magnetic responses that correspond to different values of the effective magnetic permeability. At low power of the incident field, high current amplitude states exhibit extreme diamagnetic properties corresponding to negative magnetic permeability in a narrow frequency interval.

  12. Complex inductance, excess noise, and surface magnetism in dc SQUIDs.

    Science.gov (United States)

    Sendelbach, S; Hover, D; Mück, M; McDermott, R

    2009-09-11

    We have characterized the complex inductance of dc SQUIDs cooled to millikelvin temperatures. The SQUID inductance displays a rich, history-dependent structure as a function of temperature, with fluctuations of order 1 fH. At a fixed temperature, the SQUID inductance fluctuates with a 1/f power spectrum; the inductance noise is highly correlated with the conventional 1/f flux noise. The data are interpreted in terms of the reconfiguration of clusters of surface spins, with correlated fluctuations of effective magnetic moments and relaxation times.

  13. Dynamics of a SQUID with topologically nontrivial barriers

    Science.gov (United States)

    Rahmonov, I. R.; Shukrinov, Yu. M.; Dawood, R.

    2016-03-01

    The phase dynamics of a SQUID consisting of Josephson junctions with topologically nontrivial barriers has been studied. Its comparative analysis with the dynamics of a conventional SQUID has been performed. The current-voltage characteristics have been calculated. The dependence of the return current on the magnetic field has been found. It has been shown that the branch of the current-voltage characteristic corresponding to the resonance frequency in the case of the SQUID with nontrivial barriers is displaced by √ 2 over voltage. This effect can be used for the detection of Majorana fermions.

  14. Two-stage series array SQUID amplifier for space applications

    Science.gov (United States)

    Tuttle, J. G.; DiPirro, M. J.; Shirron, P. J.; Welty, R. P.; Radparvar, M.

    We present test results for a two-stage integrated SQUID amplifier which uses a series array of d.c. SQUIDS to amplify the signal from a single input SQUID. The device was developed by Welty and Martinis at NIST and recent versions have been manufactured by HYPRES, Inc. Shielding and filtering techniques were employed during the testing to minimize the external noise. Energy resolution of 300 h was demonstrated using a d.c. excitation at frequencies above 1 kHz, and better than 500 h resolution was typical down to 300 Hz.

  15. Vortices in superconducting bulk, films and SQUIDs

    Indian Academy of Sciences (India)

    Ernst Helmut Brandt

    2006-01-01

    The properties of the ideal periodic vortex lattice in bulk superconductors and in films of any thickness can be calculated from Ginzburg-Landau theory by an iteration method using Fourier series. The London theory yields general analytic expressions for the magnetic field and energy of arbitrary arrangements of straight or curved vortex lines. The elasticity of the vortex lattice is highly nonlocal. The magnetic response of superconductors of realistic shapes like thin and thick strips and disks or thin rectangular plates or films, containing pinned vortices, can be computed within continuum theory by solving an integral equation. A useful example is a thin square with a central hole and a radial slit, used as superconducting quantum interference device (SQUID).

  16. Realizing and optimizing an atomtronic SQUID

    Science.gov (United States)

    Mathey, Amy C.; Mathey, L.

    2016-05-01

    We demonstrate how a toroidal Bose-Einstein condensate with a movable barrier can be used to realize an atomtronic SQUID. The magnitude of the barrier height, which creates the analogue of an SNS junction, is of crucial importance, as well as its ramp-up and -down protocol. For too low of a barrier, the relaxation of the system is dynamically suppressed, due to the small rate of phase slips at the barrier. For a higher barrier, the phase coherence across the barrier is suppressed due to thermal fluctuations, which are included in our Truncated Wigner approach. Furthermore, we show that the ramp-up protocol of the barrier can be improved by ramping up its height first, and its velocity after that. This protocol can be further improved by optimizing the ramp-up and ramp-down time scales, which is of direct practical relevance for on-going experimental realizations.

  17. Gear Selectivity of a Longfin Squid Bottom Trawl

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Loligo pealeii (longfin inshore squid) co-occurs with Atlantic butterfish (Peprilus triacanthus) throughout the year and discarding in the L. pealeii bottom trawl...

  18. Dc-SQUID sensor system for multichannel neuromagnetometry

    Energy Technology Data Exchange (ETDEWEB)

    Houwman, E.P.; Veldhuis, D.; Flokstra, ter Brake, H.J.M.; Jaszczuk, W.; Rogalla, H. (Univ. of Twente, Faculty of Applied Physics, P.O. Box 217, 7500 AE Enschede (NL)); Martinez, A. (Universidad de Zaragoza, E.T.S.I.I. Maria Zambrano 50, 50015 Zaragoza (ES))

    1991-03-01

    This paper reports on various DC-SQUID sensor configurations developed for use in the authors' 19-channel neuromagetometer. Apart from the standard type, resistively and indictively shunted SQUIDs were made, allowing for a large screening factor {beta} ({gt}1). In this way signal coupling from the pick-up coil to the SQUID is facilitated and capactive coupling between the input coil and the SQUID washer can be decreased. The number of turns of the input coil is decreased further by allowing for an inductance mismatch in the input circuit. Although theoretically both measures give rise to an increased field noise of the sensor, they may lead to a reduction of the excess noise and the noise balance may become positive.

  19. Chimera states and synchronization in magnetically driven SQUID metamaterials

    Science.gov (United States)

    Hizanidis, J.; Lazarides, N.; Neofotistos, G.; Tsironis, G. P.

    2016-09-01

    One-dimensional arrays of Superconducting QUantum Interference Devices (SQUIDs) form magnetic metamaterials exhibiting extraordinary properties, including tunability, dynamic multistability, negative magnetic permeability, and broadband transparency. The SQUIDs in a metamaterial interact through non-local, magnetic dipole-dipole forces, that makes it possible for multiheaded chimera states and coexisting patterns, including solitary states, to appear. The spontaneous emergence of chimera states and the role of multistability is demonstrated numerically for a SQUID metamaterial driven by an alternating magnetic field. The spatial synchronization and temporal complexity are discussed and the parameter space for the global synchronization reveals the areas of coherence-incoherence transition. Given that both one- and two-dimensional SQUID metamaterials have been already fabricated and investigated in the lab, the presence of a chimera state could in principle be detected with presently available experimental set-ups.

  20. Magnetoencephalography using a Multilayer hightc DC SQUID Magnetometer

    Science.gov (United States)

    Faley, M. I.; Poppe, U.; Borkowski, R. E. Dunin; Schiek, M.; Boers, F.; Chocholacs, H.; Dammers, J.; Eich, E.; Shah, N. J.; Ermakov, A. B.; Slobodchikov, V. Yu.; Maslennikov, Yu. V.; Koshelets, V. P.

    We describe tests of the use of a multilayer highTc DC SQUID magnetometer for magnetoencephalography (MEG) and compare our measurements with results obtained using a lowTc SQUID sensor. The integration of bias reversal readout electronics for highTc DC SQUID magnetometry into a commercial MEG data acquisition system is demonstrated. Results of measurements performed on a salinefilled head phantom are shown and the detection of an auditory evoked magnetic response of the human cortex elicited by a stimulus is illustrated. Future modifications of highTc DC SQUID sensors for applications in MEG, in order to reach a resolution of 1 fT/√Hz at 77.5 K over a wide frequency band, are outlined.

  1. DC SQUID based on the mesoscopic multiterminal Josephson junction

    OpenAIRE

    Amin, M. H. S.; Omelyanchouk, A. N.; Zagoskin, A. M.

    2001-01-01

    A theory is offered for a novel device, mesoscopic four-terminal SQUID. The studied system consists of a mesoscopic four-terminal junction, one pair of terminals of which is incorporated in a superconducting ring and the other one is connected with a transport circuit. The nonlocal weak coupling between the terminals leads to effects of phase dragging and magnetic flux transfer. The behaviour of a four-terminal SQUID, controlled by the external parameters, the applied magnetic flux and the tr...

  2. High-T(c) squid application in medicine and geophysics

    Science.gov (United States)

    Polushkin, V. N.; Uchaikin, S. V.; Vasiliev, B. V.

    1991-01-01

    In our laboratory of high-T(sub c), a one-hole squid was built from Y1Ba2Cu3O(7-x) ceramics obtained by a standard procedure of solid state reaction. The ceramics with critical current density J(sub c) is greater than 100 A/sq cm was selected. In the middle of a 10 x 10 x 2 mm ceramics pellet, a 0.8 mm hole was drilled in which the superconducting loop of the squid was located. Between the hole and the edge of the pellet, a cut was mechanically filed out with a bridge inside it connecting the superconducting ring. A scheme of the magnetometer is presented. The resonant frequency shift of the tank circuit, the connection of the squid with this circuit, and the squid inductance are evaluated. One of the most interesting fields of the squid-based magnetometer application is biomagnetism, particularly, the human heart magnetocardiogram measuring. The low-temperature squids were used in this area and many interesting and important scientific results have been obtained. The observations have shown that the main noise contribution was not due to the squid but to the Earth's magnetic field variations, industrial inductions, and mainly to the vibrations caused by liquid nitrogen boiling and by vibrations of the box. Further attempts are needed to reduce the magnetic noise inductions. Nevertheless, the estimations promise the maximum signal/noise relation of the high-T(sub c) squid-magnetocardiometer to be not less than 10:1 in a bandwidth of 60 Hz. Apparently, such resolution would be enough not only for steady cardiogram reading but even for thin structure investigation at average technique application.

  3. High transition-temperature SQUID magnetometers and practical applications

    Energy Technology Data Exchange (ETDEWEB)

    Dantsker, E [Univ. of California, Berkeley, CA (United States). Dept. of Physics

    1997-05-01

    The design, fabrication and performance of SQUID magnetometers based on thin films of the high-transition temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} (YBCO) are described. Essential to the achieving high magnetic field resolution at low frequencies is the elimination of 1/f flux noise due to thermally activated hopping of flux vortices between pinning sites in the superconducting films. Through improvements in processing, 1/f noise in single layer YBCO thin films and YBCO-SrTiO{sub 3}-YBCO trilayers was systematically reduced to allow fabrication of sensitive SQUID magnetometers. Both single-layer directly coupled SQUID magnetometers and multilayer magnetometers were fabricated, based on the dc SQUID with bicrystal grain boundary Josephson junctions. Multilayer magnetometers had a lower magnetic field noise for a given physical size due to greater effective sensing areas. A magnetometer consisting of a SQUID inductively coupled to the multiturn input coil of a flux transformer in a flip-chip arrangement had a field noise of 27 fT Hz{sup {minus}1/2} at 1 Hz and 8.5 fT Hz{sup {minus}1/2} at 1 kHz. A multiloop multilayer SQUID magnetometer had a field noise of 37 fT Hz{sup {minus}1/2} at 1 Hz and 18 fT Hz{sup {minus}1/2} at 1 kHz. A three-axis SQUID magnetometer for geophysical applications was constructed and operated in the field in the presence of 60 Hz and radiofrequency noise. Clinical quality magnetocardiograms were measured using multilayer SQUID magnetometers in a magnetically shielded room.

  4. Optical parameters of the tunable Bragg reflectors in squid

    OpenAIRE

    Ghoshal, Amitabh; DeMartini, Daniel G.; Eck, Elizabeth; Morse, Daniel E.

    2013-01-01

    Cephalopods (e.g. octopus, squid and cuttlefish) dynamically tune the colour and brightness of their skin for camouflage and communication using specialized skin cells called iridocytes. We use high-resolution microspectrophotometry to investigate individual tunable Bragg structures (consisting of alternating reflectin protein-containing, high-refractive index lamellae and low-refractive index inter-lamellar spaces) in live and chemically fixed iridocytes of the California market squid, Doryt...

  5. High transition-temperature SQUID magnetometers and practical applications

    Energy Technology Data Exchange (ETDEWEB)

    Dantsker, Eugene [Univ. of California, Berkeley, CA (United States). Dept. of Physics

    1997-05-01

    The design, fabrication and performance of SQUID magnetometers based on thin films of the high-transition temperature superconductor YBa2Cu3O7-x (YBCO) are described. Essential to the achieving high magnetic field resolution at low frequencies is the elimination of 1/f flux noise due to thermally activated hopping of flux vortices between pinning sites in the superconducting films. Through improvements in processing, 1/f noise in single layer YBCO thin films and YBCO-SrTiO3-YBCO trilayers was systematically reduced to allow fabrication of sensitive SQUID magnetometers. Both single-layer directly coupled SQUID magnetometers and multilayer magnetometers were fabricated, based on the dc SQUID with bicrystal grain boundary Josephson junctions. Multilayer magnetometers had a lower magnetic field noise for a given physical size due to greater effective sensing areas. A magnetometer consisting of a SQUID inductively coupled to the multiturn input coil of a flux transformer in a flip-chip arrangement had a field noise of 27 fT Hz-1/2 at 1 Hz and 8.5 fT Hz-1/2 at 1 kHz. A multiloop multilayer SQUID magnetometer had a field noise of 37 fT Hz-1/2 at 1 Hz and 18 fT Hz-1/2 at 1 kHz. A three-axis SQUID magnetometer for geophysical applications was constructed and operated in the field in the presence of 60 Hz and radiofrequency noise. Clinical quality magnetocardiograms were measured using multilayer SQUID magnetometers in a magnetically shielded room.

  6. DC SQUID RF magnetometer with 200 MHz bandwidth

    Science.gov (United States)

    Talanov, Vladimir; Lettsome, Nesco; Orozco, Antonio; Cawthorne, Alfred; Borzenets, Valery

    2012-02-01

    Because of periodic flux-to-voltage transfer function, Superconducting QUantum Interference Device (SQUID) magnetometers operate in a closed-loop regime [1], which linearizes the response, and increases the dynamic range and sensitivity. However, a transmission line delay between the SQUID and electronics fundamentally limits the closed-loop bandwidth at 20 MHz [1], although the intrinsic bandwidth of SQUIDs is in gigahertz range. We designed a DC SQUID based RF magnetometer capable of wideband sensing coherent magnetic fields up to 200 MHz. To overcome the closed-loop bandwidth limitation, we utilized a low-frequency flux-modulated closed-loop to simultaneously lock the quasi-static magnetic flux and provide AC bias for the RF flux. The SQUID RF voltage is processed by RF electronics based on a double lock-in technique. This yields a signal proportional to the amplitude and phase of the RF magnetic flux, with more than four decades of a linear response. For YBaCuO SQUID on bi-crystal SrTiO substrate at 77 K we achieved a flux noise density of 4 μφ0/Hz at 190 MHz, which is similar to that measured at kHz frequencies with conventional flux-locked loop. [1] D. Drung, et al., Supercond. Sci. Technol. 19, S235 (2006).

  7. [Biochemistry and functional characterization of squid mantle meat (Dosidicus gigas)].

    Science.gov (United States)

    Abugoch, L; Guarda, A; María Pérez, L; Isabel Donghi, M

    2000-12-01

    A study for the characterization of frozen giant squid mantle (meat) protein stored at -25 degrees C for 8 month was started. In the present research, the following functional properties were investigate: emulsifying, water holding and gel forming capacities. Optimal conditions for the separation and differentiation of miofibrillar and sarcoplasmatic proteins were also studied. It was found that the unfrozen giant squid mantle meat es capable of emulifying 2.817,4 g of oil/g of protein and holding capacity was 3.64 g of water/g of protein. Related to the gel forming capacity, it was not obtain, probably due to excessive storage of the meat. With regard to miofibrilar protein obtention of the squid mantle meat, it was found that two low ionic strength washings (I = 0.05), the sarcoplasmic proteins were practically eliminated from the protein matrix. The differentiation of miofibrilar and sarcoplasmatic proteins was obtained by PAGE-SDS of the squid mantle meat extracted at two different ionic strength (I = 0.05 and I = 0.5). This work demonstrates that the giant squid mantle protein has a high emulsifying and water holding capacity, and it can be used, as a raw material, for the improvement of sausage products. About the gelling products, more studies will be necessary with fresh squid mantle meat to conclude about this functional property.

  8. DC and RF Measurements of Serial Bi-SQUID Arrays

    CERN Document Server

    Prokopenko, G V; de Escobar, A Leese; Taylor, B; de Andrade, M C; Berggren, S; Longhini, P; Palacios, A; Nisenoff, M; Fagaly, R L

    2012-01-01

    SQUID arrays are promising candidates for low profile antennas and low noise amplifier applications. We present the integrated circuit designs and results of DC and RF measurements of the wideband serial arrays based on integration of linear bi-SQUID cells forming a Superconducting Quantum Interference Filter (bi-SQUID SQIF). Various configurations of serial arrays designs are described. The measured linearity, power gain, and noise temperature are analyzed and compared. The experimental results are matched to results of mathematical modeling. A serial bi-SQUID SQIF arrays are mounted into a coplanar waveguide (CPW) and symmetrically grounded to corresponding sides of CPW. The RF output comes out from the central common line, which is also used for DC biasing and forms a symmetrical balanced output. The signal and DC flux biasing line is designed as coplanar lines passed in parallel over each bi-SQUID cell in a bidirectional fashion concentrating magnetic flux inside of each cell. Serial bi-SQUID SQIF arrays ...

  9. Investigation of nanoSQUID designs for practical applications

    Science.gov (United States)

    Bechstein, Sylke; Köhn, Claudia; Drung, Dietmar; Storm, Jan-Hendrik; Kieler, Oliver; Morosh, Viacheslav; Schurig, Thomas

    2017-03-01

    In the recent past, considerable effort was spent on the development of superconducting quantum interference device (SQUID) designs for magnetic detection in the micro- and nano-scale. Where these novel nanoSQUIDs were mostly of a simple format, real applications require more elaborate designs including auxiliary components such as coils and transformers. Therefore, we have developed SQUID designs based on a Nb/HfTi/Nb thin-film technology which offers both, nano-patterning and waferscale manufacturing of complex design structures. Employing e-beam lithography and chemical–mechanical polishing process steps, the area of the superconductor–normal conductor–superconductor Josephson junctions of these nanoSQUIDs has been varied between 150 nm × 150 nm and 200 nm × 200 nm, whereas the thickness of the barrier is about 20 nm. In order to enable real practical applications, nanoSQUID designs with a number of implemented auxiliary components and design features, such as gradiometric feedback loops, gradiometric transformers, and rf filters, have been carefully investigated. This paper combines a summary of recent achievements with a presentation of detailed measurements of the device performance in magnetic fields of up to a few tens of millitesla. This investigation is intended to pave the way for future practical complex nanoSQUID tools.

  10. The low fault HTSL-SQUID cooling system. Final report; Stoerarmes HTSL-SQUID-Kuehlsystem. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Binneberg, A.; Spoerl, G.; Buschmann, H.

    1997-03-01

    In the context of the research project, work was done for HTSL-SQUID on (1) the development of a thermo-siphon cooler (low fault and continuously working) and (2) the development of a latent storage cooler (low fault and discontinuously working). Two development versions of the latent storage cooler were followed up, the development of a spherical latent storage cooler and the development of an annular vessel latent storage cooler. A further precondition for the construction of the cooler was the use of split Stirling refrigerators as units producing the cold. The experimental sample was built up with refrigerators which could produce a nominal cooling output of 1.2 W at 80 K. Two samples of the thermo-siphon cooler were built, tested and improved. The second sample was developed further as a demonstration model, introduced at meetings and prepared for testing the cooling of HTSL-SQUIDs. The thermo-siphon cooler can be designed for cooling output up to about 2 W at 80 K and can be used controlled for a temperature range of 90 K to 66 K. (orig./MM) [Deutsch] Im Rahmen des Forschungsvorhabens wurde fuer HTSL-SQUID`s an der (1) Entwicklung eines Thermosiphon-Kuehlers (stoerarm und kontinuierlich arbeitend) und (2) Entwicklung eines Latentspeicher-Kuehlers (stoerfrei und diskontinuierlich arbeitend) gearbeitet. Bei dem Latentspeicher-Kuehler wurden zwei Entwicklungsversionen verfolgt, und zwar Entwicklung eines Kugel-Latentspeicher-Kuehlers und Entwicklung eines Ringgefaess-Latentspeicher-Kuehlers. Eine weitere Praemisse zum Aufbau der Kuehler war der Einsatz von Split-Stirling-Kaeltemaschinen als kaelteerzeugende Baugruppe. Die Versuchsmuster wurden mit Kaeltemaschinen aufgebaut, die eine Nennkuehlleistung von 1,2 W bei 80 K erzeugen konnten. Der Thermosiphon-Kuehler wurde in zwei Musterexemplaren aufgebaut, erprobt und verbessert. Das Zweitmuster wurde als Demonstrator weiterentwickelt, zu Fachtagungen vorgestellt und zur Testung der Kuehlung von HTSL-SQUIDs

  11. Nuclear magnetic resonance experiments with dc SQUID amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Heaney, M.B. (California Univ., Berkeley, CA (USA). Dept. of Physics Lawrence Berkeley Lab., CA (USA))

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting QUantum Interference Devices) with Nb/Al{sub 2}O{sub 3}/Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 {times} 10{sup 17} in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO{sub 3} crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies.

  12. Nuclear magnetic resonance experiments with DC SQUID amplifiers

    Science.gov (United States)

    Heaney, M. B.

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting Quantum Interference Devices) with Nb/Al2O3/Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 x 10(exp 17) in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO3 crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies.

  13. SQUID sensor array configurations for magnetoencephalography applications

    Energy Technology Data Exchange (ETDEWEB)

    Vrba, J.; Robinson, S.E. [CTF Systems Inc., A subsidiary of VSM MedTech Ltd, Port Coquitlam, BC (Canada)

    2002-09-01

    Electrophysiological activity in the human brain generates a small magnetic field from the spatial superposition of individual neuronal source currents. At a distance of about 15 mm from the scalp, the observed field is of the order of 10{sub -13} to 10{sub -12} T peak-to-peak. This measurement process is termed magnetoencephalography (MEG). In order to minimize instrumental noise, the MEG is usually detected using superconducting flux transformers, coupled to SQUID (superconducting quantum interference device) sensors. Since MEG signals are also measured in the presence of significant environmental magnetic noise, flux transformers must be designed to strongly attenuate environmental noise, maintain low instrumental noise and maximize signals from the brain. Furthermore, the flux transformers must adequately sample spatial field variations if the brain activity is to be imaged. The flux transformer optimization for maximum brain signal-to-noise ratio (SNR) requires analysis of the spatial and temporal properties of brain activity, the environmental noise and how these signals are coupled to the flux transformer. Flux transformers that maximize SNR can detect the smallest brain signals and have the best ability to spatially separate dipolar sources. An optimal flux transformer design is a synthetic higher-order gradiometer based on relatively short-baseline first-order radial gradiometer primary sensors. (author)

  14. High-Tc SQUIDs: Noise and applications

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Hsiao-Mei [Univ. of Houston, TX (United States)

    2001-08-01

    A major challenge in the design and operation of high transition temperature (Tc ) Superconducting Quantum Interference Devices (SQUIDs) is their potential to exhibit substantially higher levels of noise at low frequency f when exposed to earth’s magnetic field. To investigate this problem, we studied the noise of high-Tc SQUIDs, directly coupled magnetometers and multilayer magnetometers in both static and changing magnetic fields. The directly coupled magnetometer consists of a dc SQUID connected to a large area pickup loop in parallel. The multilayer magnetometer involves a multiturn flux transformer inductively coupled to a dc SQUID on a separate substrate. All the devices are made of thin films of the high-Tc superconductor YBa2Cu3O7-δ, patterned into 4 μm linewidths. After cooling in a magnetic field, the devices showed no increase in 1/f noise for fields up to threshold values well above the earth’s magnetic field. The devices were also cooled in a magnetic field that was subsequently turned off. The 1/f noise of bare SQUIDs was unchanged for fields up to 12 μT. The addition of the flux transformer containing flux dams increased the sensitivity to magnetic field by a factor of 43 while reducing the threshold field only moderately, to 5 μT. This result implies that the multilayer magnetometer can be rotated in the earth’s magnetic field through an angle of up to 26o without increasing the low frequency noise. The results of these studies were incorporated into a 5-channel high-Tc magnetocardiography system involving two first-derivative SQUID gradiometers and three reference SQUIDs. Each planar gradiometer consists of a directly coupled SQUID magnetometer inductively coupled to the smaller coil of an asymmetric, two-loop flux transformer. The reference SQUIDs are patterned into 4 μm lines. The outputs of the five channels were subtracted in software to form a second-derivative gradiometer. Its

  15. Environmental effects on recreational squid jigging fishery catches

    Science.gov (United States)

    Cabanellas-Reboredo, Miguel; Alós, Josep; Palmer, Miquel; Morales-Nin, Beatriz

    2012-08-01

    Experimental fishing sessions simulating the operating procedures of the recreational fishery for the European squid that operates at inshore Palma Bay (Balearic Islands, Spain) were conducted to investigate the effects of environmental variables on squid catches. The catch per unit of effort (cpue) of recreational-like jigging sessions showed a seasonal pattern (higher cpue during colder months). Two alternative hypotheses can explain such a pattern. First, squid could migrate inshore during colder months to seek spatio-temporal windows within which the sea temperature maximize spawning success. Second, the timing of the seasonal reproductive peak and the growth rate of any given cohort would result in a higher percentage of squid whose body size is greater than the gear-specific vulnerability threshold during the colder months. The combination of environmental variables that maximized cpue was a low sea surface temperature, a low windspeed, low atmospheric pressure, and days close to the new moon. A specific period of the day, narrowly around sunset, favoured the catches. Within this narrow period, the sunlight is still sufficient to allow the recreational fishing lures to be effective, and the squid have already shifted to a more active pattern of movement characteristic of the night-time period.

  16. SQUIDs De-fluxing Using a Decaying AC Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Matlashov, Andrei Nikolaevich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Semenov, Vasili Kirilovich [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Anderson, Bill [Senior Scientific, LLC, Albuquerque, NM (United States)

    2016-06-08

    Flux trapping is the Achilles’ heel of all superconductor electronics. The most direct way to avoid flux trapping is a prevention of superconductor circuits from exposure to magnetic fields. Unfortunately this is not feasible if the circuits must be exposed to a strong DC magnetic field even for a short period of time. For example, such unavoidable exposures take place in superparamagnetic relaxation measurements (SPMR) and ultra-low field magnetic resonance imaging (ULF MRI) using unshielded thin-film SQUID-based gradiometers. Unshielded SQUIDs stop working after being exposed to DC magnetic fields of only a few Gauss in strength. In this paper we present experimental results with de-fluxing of planar thin-film LTS SQUID-based gradiometers using a strong decaying AC magnetic field. We used four commercial G136 gradiometers for SPMR measurements with up to a 10 mT magnetizing field. Strong 12.9 kHz decaying magnetic field pulses reliably return SQUIDs to normal operation 50 ms after zeroing the DC magnetizing field. This new AC de-fluxing method was also successfully tested with seven other different types of LTS SQUID sensors and has been shown to dissipate extremely low energy.

  17. 3-channel double relaxation oscillation SQUID magnetometer system with simple readout electronics

    NARCIS (Netherlands)

    Lee, Y.H.; Kim, J.M.; Kwon, H.C.; Park, Y.K.; Park, J.C.; Duuren, van M.J.; Adelerhof, D.J.; Flokstra, J.; Rogalla, H.

    1995-01-01

    Recently several approaches have been made to simplify the readout scheme of the standard dc SQUID. A double relaxation oscillation SQUID(DROS) consisting of a hysteretic dc SQUID and a reference junction in series shunted by an inductor and a resistor can provide a very large flux-to-voltage transf

  18. Application of SQUIDs for registration of biomagnetic signals

    Science.gov (United States)

    Voitovych, I. D.; Primin, M. A.; Sosnytskyy, V. N.

    2012-04-01

    Supersensitive magnetometric systems based on low-temperature SQUIDs have been designed to conduct research in cardiology (magnetocardiography) and to examine distribution of magnetic nanoparticles in biologic objects. Such SQUID magnetometric systems are distinguished by their noise immunity enabling research in nonscreened rooms. High repeatability of research outcomes has been confirmed. The use of magnetocardiographic systems has permitted a new screening information technology to be developed to diagnose heart diseases at early stages. Magnetic imaging of heart's action currents is an ideal way to test local electrical heterogeneity of myocardium. It is shown that magnetocardiography has a significant potential for both basic science of analysis of heart's biosignals and clinical cardiologic practice. A SQUID magnetometric system measuring magnetic signals radiated by the organs of laboratory animals is described. Information technology for automatic recording and transforming magnetometric data has been developed; the measurement of signals over rats' livers while injecting intravenously the nanoparticles of iron oxides and lead solutions are presented.

  19. Chimeras in locally coupled SQUIDs: Lions, goats and snakes

    CERN Document Server

    Hizanidis, J; Tsironis, G P

    2016-01-01

    We report on the emergence of robust multi-clustered chimera states in a dissipative-driven system of symmetrically and locally coupled identical SQUID oscillators. The "snake-like" resonance curve of the single SQUID (Superconducting QUantum Interference Device) is the key to the formation of the chimera states and is responsible for the extreme multistability exhibited by the coupled system that leads to attractor crowding at the geometrical resonance frequency. Until now, chimera states were mostly believed to exist for nonlocal coupling. Our findings provide theoretical evidence that nearest neighbor interactions is indeed capable of supporting such states in a wide parameter range. SQUID metamaterials are the subject of intense experimental investigations and we are highly confident that the complex dynamics demonstrated in this manuscript can be confirmed in the laboratory.

  20. Robust chimera states in SQUID metamaterials with local interactions

    Science.gov (United States)

    Hizanidis, J.; Lazarides, N.; Tsironis, G. P.

    2016-09-01

    We report on the emergence of robust multiclustered chimera states in a dissipative-driven system of symmetrically and locally coupled identical superconducting quantum interference device (SQUID) oscillators. The "snakelike" resonance curve of the single SQUID is the key to the formation of the chimera states and is responsible for the extreme multistability exhibited by the coupled system that leads to attractor crowding at the geometrical resonance (inductive-capacitive) frequency. Until now, chimera states were mostly believed to exist for nonlocal coupling. Our findings provide theoretical evidence that nearest-neighbor interactions are indeed capable of supporting such states in a wide parameter range. SQUID metamaterials are the subject of intense experimental investigations, and we are highly confident that the complex dynamics demonstrated in this paper can be confirmed in the laboratory.

  1. The response of small SQUID pickup loops to magnetic fields

    Science.gov (United States)

    Kirtley, John R.; Paulius, Lisa; Rosenberg, Aaron J.; Palmstrom, Johanna C.; Schiessl, Daniel; Jermain, Colin L.; Gibbons, Jonathan; Holland, Connor M.; Fung, Y.-K.-K.; Huber, Martin E.; Ketchen, Mark B.; Ralph, Daniel C.; Gibson, Gerald W., Jr.; Moler, Kathryn A.

    2016-12-01

    In the past, magnetic images acquired using scanning superconducting quantum interference device (SQUID) microscopy have been interpreted using simple models for the sensor point spread function. However, more complicated modeling is needed when the characteristic dimensions of the field sensitive areas in these sensors become comparable to the London penetration depth. In this paper we calculate the response of SQUIDs with deep sub-micron pickup loops to different sources of magnetic fields by solving coupled London’s and Maxwell’s equations using the full sensor geometry. Tests of these calculations using various field sources are in reasonable agreement with experiments. These calculations allow us to more accurately interpret sub-micron spatial resolution data obtained using scanning SQUID microscopy.

  2. High-resolution displacement sensor using squid array amplifier

    Science.gov (United States)

    Chui, T.; Penanen, K.; Barmatz, M.; Paik, H.

    Improvement in the measurement of displacement has profound implications for gravitational physics. Examples of high-impact projects that can benefit from a better displacement sensor are: detection of gravitational waves, test of the equivalence principle, search for the postulated ?axion? particle, and test of the inverse square law of gravity. We describe the concept of a new displacement sensor that makes use of a recent development in the Superconducting Quantum Interference Device (SQUID) technology. The SQUID array amplifier, invented by Welty and Martinis (IEEE Trans. Appl. Superconductivity 3, 2605, 1993), has about the same noise as a conventional SQUID; however, it can work at a much higher frequency of up to 5 MHz. We explain how the higher bandwidth can be translated into higher resolution using a bridge-balancing scheme that can simultaneously balance out both the carrier signal at the bridge output and the electrostatic force acting on the test mass.

  3. Polarization rotation by an rf-SQUID metasurface

    CERN Document Server

    Caputo, J -G; Maimistov, A I

    2015-01-01

    We study the transmission and reflection of a plane electromagnetic wave through a two dimensional array of rf-SQUIDs. The basic equations describing the amplitudes of the magnetic field and current in the split-ring resonators are developed. These yield in the linear approximation the reflection and transmission coefficients. The polarization of the reflected wave is independent of the frequency of the incident wave and of its polarization; it is defined only by the orientation of the split-ring. The reflection and transmission coefficients have a strong resonance that is determined by the parameters of the rf-SQUID; its strength depends essentially on the incident angle.

  4. Polarization rotation by an rf-SQUID metasurface

    Science.gov (United States)

    Caputo, J.-G.; Gabitov, I.; Maimistov, A. I.

    2015-03-01

    We study the transmission and reflection of a plane electromagnetic wave through a two-dimensional array of rf-SQUIDs. The basic equations describing the amplitudes of the magnetic field and current in the split-ring resonators are developed. These yield in the linear approximation the reflection and transmission coefficients. The polarization of the reflected wave is independent of the frequency of the incident wave and of its polarization; it is defined only by the orientation of the split ring. The reflection and transmission coefficients have a strong resonance that is determined by the parameters of the rf-SQUID; its strength depends essentially on the incident angle.

  5. An Economical Magnetocardiogram System Based on High-Tc SQUIDs

    Institute of Scientific and Technical Information of China (English)

    LI Zhuo; ZHU Xue-Min; ZHANG Li-Hua; HUANG Xu-Guang; REN Yu-Feng; CHEN Geng-Hua; YANG Qian-Sheng; FENG Ji

    2006-01-01

    @@ An economical magnetocardiogram (MCG) system is built in our laboratory. It mainly consists of a MCG data acquisition stage equipped with two high-Tc superconducting quantum interference device (SQUID) magnetometers,a data processing stage with digital filtering and a one-layer μ-metal magnetically shielded room in conjunction with a high-Tc SQUID based active compensation. Experimental results show that a noise level of pico-tesla in MCG profiles, which is necessary for clinical applications, may be achieved with the system. Moreover, stable and convenient operations of the system are demonstrated with simulating MCG measurements.

  6. A Simple Quantum Integro-Differential Solver (SQuIDS)

    CERN Document Server

    Delgado, Carlos Alberto Arguelles; Weaver, Christopher N

    2014-01-01

    Simple Quantum Integro-Differential Solver (SQuIDS) is a C++ code designed to solve semi-analytically the evolution of a set of density matrices and scalar functions. This is done efficiently by expressing all operators in an SU(N) basis. SQuIDS provides a base class from which users can derive new classes to include new non-trivial terms from the right hand sides of density matrix equations. The code was designed in the context of solving neutrino oscillation problems, but can be applied to any problem that involves solving the quantum evolution of a collection of particles with Hilbert space of dimension up to six.

  7. Investigation of 1/f noise in tunnel junction dc SQUIDS

    Energy Technology Data Exchange (ETDEWEB)

    Koch, R.; Clarke, J.; Goubau, W.; Harlingen; Martinis, J.; Pegrum, C.

    1983-05-01

    The authors describe two methods of measuring the 1/f noise in a dc SQUID. One is sensitive only to 1/f noise in the critical currents of the junctions, and the other is sensitive only to 1/f flux noise that is not associated with critical current fluctuations. From measurements on a planar thin-film dc SQUID incorporating Josephson tunnel junctions the authors conclude that the predominant source of 1/f noise is not noise in the critical currents, but rather an apparent flux noise of unknown origin.

  8. Radiation detection from phase-locked serial dc SQUID arrays

    DEFF Research Database (Denmark)

    Kaplunenko, V. K.; Mygind, Jesper; Pedersen, Niels Falsig;

    1993-01-01

    We report on synchronous operation of series arrays of inductively coupled superconducting quantum interference devices (SQUIDs). Each array consisted of N=3 or 11 dc SQUIDs with common inductances providing a strong interaction between neighboring cells. Externally shunted (betac...... on the external loading. For small loading it was N times smaller than expected for a single cell. The influence of the inductive coupling mechanism on the operation of discrete Josephson junction circuits and the similarity to the coupling in layered structures of long Josephson junctions is discussed. Journal...

  9. Application of squids in the Iwate create project

    Energy Technology Data Exchange (ETDEWEB)

    Yoshizawa, M. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan)]. E-mail: yoshizawa@iwate-u.ac.jp; He, D.F. [Iwate Industrial Promotion Center, Morioka 020-0045 (Japan); Nakai, K. [School of Medicine, Iwate Medical University, Morioka 020-8505 (Japan); Kobayashi, K. [Faculty of Engineering, Iwate University, Morioka 020-8551 (Japan); Nakamura, Y. [Iwate Industrial Promotion Center, Morioka 020-0045 (Japan); Yaegashi, M. [Iwate Industrial Promotion Center, Morioka 020-0045 (Japan); Ito, M. [Iwate Industrial Promotion Center, Morioka 020-0045 (Japan); Yashiro, H. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan); Daibo, M. [Faculty of Engineering, Iwate University, Morioka 020-8551 (Japan); Simizu, T. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan); Iwate Industrial Promotion Center, Morioka 020-0045 (Japan); Uchikawa, Y. [Faculty of Science and Engineering, Tokyo Denki University, Saitama 350-0394 (Japan); Noto, K. [Iwate Industrial Promotion Center, Morioka 020-0045 (Japan)

    2005-10-01

    We have developed a 64-channel magnetocardiograph (MCG) system for the diagnosis of heart disease. The MCG is characterized by its display of a unique three-dimensional image of bio-currents flowing inside the human body. The outline of the heart can be displayed without use of MRI. A mobile SQUID-based non-distractive evaluation apparatus was realized by the active shielding technique. The system can offer information from beneath the surface of the specimen by using a saw-wave excitation method. This mobile technology enables us to inspect ferromagnetic materials, whose high magnetic field rules out the use of a conventional SQUID apparatus near them.

  10. SQUID magnetometer with YBa sub 2 Cu sub 3 O sub 7 grain boundary step contacts

    CERN Document Server

    Krämer, A

    2002-01-01

    The report describes the assembly and characterisation of SQUID magnetometers consisting of a SQUID and a coupled superconducting flux antenna. Two concepts for coupling of the antenna were implemented: First, a directly coupled magnetometer in which the flux antenna is produced parallel to the SQUID, i.e. only a single YBCO layer is required; secondly, a flip-chip magnetometer where the flux antenna is produced on a different substrate and is coupled to the SQUID inductively. The SQUIDs were produced on the basis of grain boundary step contacts.

  11. High-T{sub c} DC SQUID system cooled by pulse-tube cooler

    Energy Technology Data Exchange (ETDEWEB)

    He, D.F.; Nakamura, M.; Yoshizawa, M

    2003-10-15

    We developed a high-T{sub c} DC SQUID system cooled by pulse-tube cooler. To avoid the influence of the wire resistance between SQUID and preamplifier, and to reduce the influence of the temperature fluctuation of pulse-tube cooler, DC coupling between SQUID chip and preamplifier was used and the flux locked loop worked in modulation mode. We also developed a temperature controller, using the DC SQUID as temperature sensor, to control and stabilize the operating temperature of the pulse-tube cooler. With the temperature controller, the DC SQUID system could remain locked for over 8 h.

  12. MgB2 tunnel junctions and SQUIDs

    NARCIS (Netherlands)

    Brinkman, A.; Rowell, J.M.

    2007-01-01

    Recent advances in the realization and understanding of MgB2 tunnel junctions and SQUIDs are surveyed. High quality MgB2 junctions with suitable tunnel barriers have been realized based on both oriented and epitaxial thin MgB2 films. Multiband transport properties, such as the existence of two energ

  13. A YBCO RF-SQUID magnetometer and its applications

    Science.gov (United States)

    Luwei, Zhou; Jingwu, Qiu; Xienfeng, Zhang; Zhiming, Tank; Yongjia, Qian

    1990-01-01

    An applicable RF-superconducting quantum interference detector (SQUID) magnetometer was made using a bulk sintered yttrium barium copper oxide (YBCO). The temperature range of the magnetometer is 77 to 300 K and the field range 0 to 0.1T. At 77 K, the equivalent flux noise of the SQUID is 5 x 10 to minus 4 power theta sub o/square root of Hz at the frequency range of 20 to 200 Hz. The experiments show that the SQUID noise at low-frequency end is mainly from 1/f noise. A coil test shows that the magnetic moment sensitivity delta m is 10 to the minus 6th power emu. The RF-SQUID is shielded in a YBCO cylinder with a shielding ability B sub in/B sub ex of about 10 to the minus 6th power when external dc magnetic field is about a few Oe. The magnetometer is successfully used in characterizing superconducting thin films.

  14. HTS dc SQUID based rf amplifier: development concept

    DEFF Research Database (Denmark)

    Prokopenko, G.V.; Shitov, S.V.; Borisenko, I.V.;

    2002-01-01

    We present a concept of a rf amplifier based on a directly coupled dc SQUID with bicrystal junctions, which have high saturation power and can be used with SIS mixers or possibly for satellite and cellular phone communications. A novel input resonant circuit is proposed using single layer of HTS...

  15. SQUID and magneto-optic investigations of flux turbulence

    DEFF Research Database (Denmark)

    Koblischka, M.R.; Johansen, T.H.; Baziljevich, M.

    2000-01-01

    Instabilities of the critical state ("turbulence") are observed in various high-T-c, single crystals by means of magneto-optic (MO) imaging. Using the same samples as in the MO investigations, we observe for the first time characteristic steps in the magnetic moment measured by means of a SQUID s...

  16. Quantum behavior of a SQUID qubit manipulated with fast pulses

    Energy Technology Data Exchange (ETDEWEB)

    Spilla, Samuele; Messina, Antonino; Napoli, Anna [Dipartimento di Fisica dell' Universita di Palermo, Via Archirafi 36, 90123 Palermo (Italy); Castellano, Maria Gabriella; Chiarello, Fabio [Istituto Fotonica e Nanotecnologie - CNR, Roma (Italy); Migliore, Rosanna [Institute of Biophysics, National Research Council, via Ugo La Malfa 153, 90146 Palermo (Italy)

    2013-07-01

    A SQUID qubit manipulated with fast variation of the energy potential is analyzed. Varying the potential shape from a single to a double-well configuration, quantum behaviors are brought into light and discussed. We show that the presence of quantum coherences in the initial state of the system plays a central role in the appearance of these quantum effects.

  17. Basic and applied magnetism with a squid gradiometer

    Science.gov (United States)

    Weinstock, H.; Nisenoff, M. N.; Erber, T.

    1985-12-01

    A facility was established to evaluate the magnetic signatures of cryocoolers, i.e., small closed-cycle liquid helium refrigerators, by use of a (superconducting) SQUID gradiometer. This gradiometer also was utilized to study the: (1) threshold of Barkhausen emission and onset of hysteresis in iron, (2) detection of defects in metal pipes by remote sensing, and (3) magnetoelastic behavior in steel bars.

  18. Flicker (1/f) noise in tunnel junction DC SQUIDS

    Energy Technology Data Exchange (ETDEWEB)

    Koch, R.H.; Clarke, J.; Goubau, W.M.; Martinis, J.M.; Pegrum, C.M.; Van Harlingen, D.J.

    1983-04-01

    We have measured the spectral density of the 1/f voltage noise in current-biased resistively shunted Josephson tunnel junctions and dc SQUIDs. A theory in which fluctuations in the temperature give rise to fluctuations in the critical current and hence in the voltage predicts the magnitude of the noise quite accurately for junctions with areas of about 2 x 10/sup 4/ ..mu..m/sup 2/, but significantly overestimates the noise for junctions with areas of about 6 ..mu..m/sup 2/. DC SQUIDs fabricated from these two types of junctions exhibit substantially more 1/f voltage noise than would be predicted from a model in which the noise arises from critical current fluctuations in the junctions. This result was confirmed by an experiment involving two different bias current and flux modulation schemes, which demonstrated that the predominant 1/f voltage noise arises not from critical current fluctuations, but from some unknown source that can be regarded as an apparent 1/f flux noise. Measurements on five different configurations of dc SQUIDs fabricated with thin-film tunnel junctions and with widely varying areas, inductances, and junction capacitances show that the spectral density of the 1/f equivalent flux noise is roughtly constant, within a factor of three of (10/sup -10//f)phi/sup 2//sub 0/Hz/sup -1/. It is emphasized that 1/f flux noise may not be the predominant source of 1/f noise in SQUIDS fabricated with other technologies.

  19. Nanosquid magnetometers and high resolution scanning squid microscopy

    NARCIS (Netherlands)

    Troeman, Aico Giardano Paul

    2007-01-01

    Recent interest in the development of small sized superconducting quantum interference devices (SQUIDs) has been motivated by the applicability of these sensors for the investigation of small, local, magnetic signals, such as the magnetization reversal of small magnetic clusters and the observation

  20. A method of background noise cancellation for SQUID applications

    Energy Technology Data Exchange (ETDEWEB)

    He, D F [Iwate Industrial Promotion Center, Morioka 020-0045 (Japan); Yoshizawa, M [Faculty of Engineering, Iwate University, Morioka 020-8551 (Japan)

    2003-12-01

    When superconducting quantum inference devices (SQUIDs) operate in low-cost shielding or unshielded environments, the environmental background noise should be reduced to increase the signal-to-noise ratio. In this paper we present a background noise cancellation method based on a spectral subtraction algorithm. We first measure the background noise and estimate the noise spectrum using fast Fourier transform (FFT), then we subtract the spectrum of background noise from that of the observed noisy signal and the signal can be reconstructed by inverse FFT of the subtracted spectrum. With this method, the background noise, especially stationary inferences, can be suppressed well and the signal-to-noise ratio can be increased. Using high-T{sub C} radio-frequency SQUID gradiometer and magnetometer, we have measured the magnetic field produced by a watch, which was placed 35 cm under a SQUID. After noise cancellation, the signal-to-noise ratio could be greatly increased. We also used this method to eliminate the vibration noise of a cryocooler SQUID.

  1. A 128 Multiplexing Factor Time-Domain SQUID Multiplexer

    Science.gov (United States)

    Prêle, D.; Voisin, F.; Piat, M.; Decourcelle, T.; Perbost, C.; Chapron, C.; Rambaud, D.; Maestre, S.; Marty, W.; Montier, L.

    2016-07-01

    A cryogenic 128:1 Time-Domain Multiplexer (TDM) has been developed for the readout of kilo-pixel Transition Edge Sensor (TES) arrays dedicated to the Q&U Bolometric Interferometer for Cosmology (QUBIC) instrument which aims to measure the B-mode polarization of the Cosmic Microwave Background. Superconducting QUantum Interference Devices (SQUIDs) are usually used to read out TESs. Moreover, SQUIDs are used to build TDM by biasing sequentially the SQUIDs connected together—one for each TES. In addition to this common technique which allows a typical 32 multiplexing factor, a cryogenic integrated circuit provides a 4:1 second multiplexing stage. This cryogenic integrated circuit is one of the original part of our TDM achieving an unprecedented 128 multiplexing factor. We present these two dimension TDM stages: topology of the SQUID multiplexer, operation of the cryogenic integrated circuit, and integration of the full system to read out a TES array dedicated to the QUBIC instrument. Flux-locked loop operation in multiplexed mode is also discussed.

  2. SQUIDs in biomagnetism: a roadmap towards improved healthcare

    Science.gov (United States)

    Körber, Rainer; Storm, Jan-Hendrik; Seton, Hugh; Mäkelä, Jyrki P.; Paetau, Ritva; Parkkonen, Lauri; Pfeiffer, Christoph; Riaz, Bushra; Schneiderman, Justin F.; Dong, Hui; Hwang, Seong-min; You, Lixing; Inglis, Ben; Clarke, John; Espy, Michelle A.; Ilmoniemi, Risto J.; Magnelind, Per E.; Matlashov, Andrei N.; Nieminen, Jaakko O.; Volegov, Petr L.; Zevenhoven, Koos C. J.; Höfner, Nora; Burghoff, Martin; Enpuku, Keiji; Yang, S. Y.; Chieh, Jen-Jei; Knuutila, Jukka; Laine, Petteri; Nenonen, Jukka

    2016-11-01

    Globally, the demand for improved health care delivery while managing escalating costs is a major challenge. Measuring the biomagnetic fields that emanate from the human brain already impacts the treatment of epilepsy, brain tumours and other brain disorders. This roadmap explores how superconducting technologies are poised to impact health care. Biomagnetism is the study of magnetic fields of biological origin. Biomagnetic fields are typically very weak, often in the femtotesla range, making their measurement challenging. The earliest in vivo human measurements were made with room-temperature coils. In 1963, Baule and McFee (1963 Am. Heart J. 55 95-6) reported the magnetic field produced by electric currents in the heart (‘magnetocardiography’), and in 1968, Cohen (1968 Science 161 784-6) described the magnetic field generated by alpha-rhythm currents in the brain (‘magnetoencephalography’). Subsequently, in 1970, Cohen et al (1970 Appl. Phys. Lett. 16 278-80) reported the recording of a magnetocardiogram using a Superconducting QUantum Interference Device (SQUID). Just two years later, in 1972, Cohen (1972 Science 175 664-6) described the use of a SQUID in magnetoencephalography. These last two papers set the scene for applications of SQUIDs in biomagnetism, the subject of this roadmap. The SQUID is a combination of two fundamental properties of superconductors. The first is flux quantization—the fact that the magnetic flux Φ in a closed superconducting loop is quantized in units of the magnetic flux quantum, Φ0 ≡ h/2e, ≈ 2.07 × 10-15 Tm2 (Deaver and Fairbank 1961 Phys. Rev. Lett. 7 43-6, Doll R and Näbauer M 1961 Phys. Rev. Lett. 7 51-2). Here, h is the Planck constant and e the elementary charge. The second property is the Josephson effect, predicted in 1962 by Josephson (1962 Phys. Lett. 1 251-3) and observed by Anderson and Rowell (1963 Phys. Rev. Lett. 10 230-2) in 1963. The Josephson junction consists of two weakly coupled superconductors

  3. A SQUID gradiometer module with wire-wound pickup antenna and integrated voltage feedback circuit

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Guofeng [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Yi, E-mail: y.zhang@fz-juelich.de [Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Zhang Shulin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Krause, Hans-Joachim [Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); and others

    2012-10-15

    The performance of the direct readout schemes for dc SQUID, Additional Positive Feedback (APF), noise cancellation (NC) and SQUID bootstrap circuit (SBC), have been studied in conjunction with planar SQUID magnetometers. In this paper, we examine the NC technique applied to a niobium SQUID gradiometer module with an Nb wire-wound antenna connecting to a dual-loop SQUID chip with an integrated voltage feedback circuit for suppression of the preamplifier noise contribution. The sensitivity of the SQUID gradiometer module is measured to be about 1 fT/(cm {radical}Hz) in the white noise range in a magnetically shielded room. Using such gradiometer, both MCG and MEG signals are recorded.

  4. Medical applications of SQUIDs in neuro- and cardiomagnetism

    Science.gov (United States)

    Lounasmaa, Olli V.

    1996-01-01

    Magnetoencephalography (MEG) and magnetocardiography (MCG) are two completely non-invasive imaging techniques, suitable for basic and clinical studies of human subjects. Large SQUID arrays, operating at liquid helium temperatures, are employed for detecting and localizing magnetically the active regions, modelled by current dipoles, in the working brain or heart. The measurements must be performed in magnetically shielded rooms. Time resolution of both methods is 0.5 ms and spatial accuracy 5-6mm. Commercial multi-SQUID instruments are now available from several manufacturers. An adequate account of the theory and practice of both techniques is given. Three examples of brain studies and two investigations of the heart are described. The advantages and drawbacks of modern imaging techniques, including MRI and PET, are compared and the future of MEG and MCG is discussed.

  5. Low-frequency Flux Noise in SQUIDs and Superconducting Qubits

    Science.gov (United States)

    Sendelbach, Steven; Hover, David; Kittel, Achim; Mueck, Michael; McDermott, Robert

    2008-03-01

    Superconducting qubits are a leading candidate for scalable quantum information processing. In order to realize the full potential of these qubits, it is necessary to develop a more complete understanding of the microscopic physics that governs dissipation and dephasing of the quantum state. In the case of the Josephson phase and flux qubits, the dominant dephasing mechanism is an apparent low-frequency magnetic flux noise with a 1/f spectrum. The origin of this excess noise is not understood. We report the results of SQUID measurements that explore the dependence of the excess low-frequency flux noise on SQUID inductance, geometry, materials, and temperature. We discuss contributions to the measured noise from temperature fluctuations, trapped vortices in the superconducting films, and surface magnetic states in the native oxides of the superconductors. We discuss implications of our measurements for qubit dephasing.

  6. Scanning SQUID microscopy in a cryogen-free refrigerator

    Science.gov (United States)

    Schaefer, Brian T.; Low, David; Prawiroatmodjo, Guenevere E. D. K.; Nangoi, J. Kevin; Kim, Jihoon; Nowack, Katja C.

    With helium prices rising and supply becoming increasingly uncertain, it has become attractive to use dry cryostats with cryocoolers rather than liquid helium to reach low temperatures. However, a cryocooler introduces vibrations at the sample stage, making scanning probe experiments more challenging. Here, we report our progress on a superconducting quantum interference device (SQUID) microscope implemented for the first time in a compact, cryogen-free 5 K system. Our microscope is designed to reach submicron spatial resolution and a flux sensitivity of approximately 1 μΦ0 /√{ Hz} , where Φ0 is the magnetic flux quantum. To enable height feedback while approaching and scanning samples, we mount the SQUID on a quartz tuning fork. Our system promises to meet the capabilities of similar systems implemented in helium cryostats.

  7. nanoSQUID operation using kinetic rather than magnetic induction.

    Science.gov (United States)

    McCaughan, Adam N; Zhao, Qingyuan; Berggren, Karl K

    2016-06-14

    We report on a method of nanoSQUID modulation which uses kinetic inductance rather than magnetic inductance to manip-ulate the internal fluxoid state. We produced modulation using injected current rather than an applied magnetic field. Using this injected current, we were able to observe the triangle-wave shaped modulation of the device critical current which was periodic according to the London fluxoid quantization condition. The measurement results also confirmed that the fluxoid state inside a superconducting loop can be manipulated using primarily kinetic inductance. By using primarily kinetic inductance rather than magnetic inductance, the size of the coupling inductor was reduced by a factor of 10. As a result, this approach may provide a means to reduce the size of SQUID-based superconducting electronics. Additionally, this method provides a convenient way to perform kinetic inductance characterizations of superconducting thin films.

  8. A three-axis SQUID-based absolute vector magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Schönau, T.; Schmelz, M.; Stolz, R.; Anders, S.; Linzen, S.; Meyer, H.-G. [Department of Quantum Detection, Leibniz Institute of Photonic Technology, Jena 07745 (Germany); Zakosarenko, V.; Meyer, M. [Supracon AG, An der Lehmgrube 11, Jena 07751 (Germany)

    2015-10-15

    We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth’s magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz{sup 1/2}. The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration.

  9. A three-axis SQUID-based absolute vector magnetometer.

    Science.gov (United States)

    Schönau, T; Zakosarenko, V; Schmelz, M; Stolz, R; Anders, S; Linzen, S; Meyer, M; Meyer, H-G

    2015-10-01

    We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth's magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz(1/2). The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration.

  10. Low Frequency Nuclear Quadrupole Resonance with SQUID Amplifiers

    Science.gov (United States)

    Clarke, John

    1994-02-01

    The dc SQUID (Superconducting QUantum Interference Device) can be configured as an ampli­fier of spin-echos with a noise temperature of approximately 10 mK (f/1 M Hz) at an operating temperature of 1.5 K. A Fourier transform spectrometer based on a SQUID with a superconducting input circuit and operated in a flux-locked loop is used to obtain nuclear quadrupole resonance (NQR) spectra in a broadband m ode over the bandwith 0 -1 M Hz. Spin-echo spectra of 14N in NH4ClO4 reveal sharp NQR resonances, obtained simultaneously, at 17.4, 38.8 and 56.2 kHz. At 1.5 K, the measured longitudinal and transverse relaxation times T1 and T2 for the 38.8 kHz transition are 63 ± 3 ms and 22±2 ms, respectively.

  11. SQUID Magnetometry for Cancer Screening a Feasibility Study

    CERN Document Server

    Kenning, G G; Zotev, V S; Moslemi, A; Wilson, S; Hawel, L; Byus, C; Kovach, J S

    2003-01-01

    The recent demonstration that nanoparticles associated with various biological molecules and pharmacological agents can be administered systemically to humans, without toxicity from the particles, has opened a new era in the targeting of such particles to specific tissues in the body for the imaging and therapy of disease. The majority of particles used for this purpose contain iron and are detected in the body by magnetic resonance imaging. We believe a superconducting quantum interference device (SQUID) could provide quantitative and spatial information relevant to localization of superparamagnetic nanoparticles directed to a specific cell target in vivo. We envision a scanning system consisting of a DC induction field, a transport device, and an array of planar first order gradiometer coils coupled to DC SQUID amplifiers. We performed a set of computer simulations using experimentally determined values for concentrations of paramagnetic particles achievable in specific tissues of the mouse in vivo and conc...

  12. Size increment of jumbo flying squid Dosidicus gigas mature females in Peruvian waters, 1989-2004

    Science.gov (United States)

    Argüelles, Juan; Tafur, Ricardo; Taipe, Anatolio; Villegas, Piero; Keyl, Friedeman; Dominguez, Noel; Salazar, Martín

    2008-10-01

    Changes in population structure of the jumbo flying squid Dosidicus gigas in Peruvian waters were studied based on size-at-maturity from 1989 to 2004. From 1989 to 1999, mature squid belonging to the medium-sized group prevailed, but from 2001 on, mature squids were larger. This change is not related to the changes in sea surface temperature and we hypothesized that it was caused by the population increase of mesopelagic fishes as prey.

  13. Modified SQUID Operator Equation for a Single-Qubit Structure Coupled to a Quantum Resonator

    Institute of Scientific and Technical Information of China (English)

    LIANG Bao-Long; WANG Ji-Suo; FAN Hong-Yi; MENG Xiang-Guo

    2008-01-01

    Role of self-inductance in superconducting quantum interference device (SQUID) charge qubit is considered. It is found that when an SQUID charge qubit is coupled to a quantum LC resonator, the SQUID voltage operator equation is modified in accompanying with the modification of operator Faraday equation describing the inductance. It is shown that when the extra energy is applied to the junction, the mean phase will be squeezed according to a damping factor.

  14. Electromagnetic Field Scattering on rf-SQUID Based Metasurfaces

    OpenAIRE

    Сaputo J.G; Gabitov I.R.; Kudyshev Zh.; Kupaev T.; Maimistov A.I.

    2015-01-01

    Electromagnetic field scattering on a 2D array of rf-SQUIDs is considered. We show that the scattering changes for large amplitudes of the incident electromagnetic wave; above a critical amplitude, two different refraction states occur (bistability). In particular, for these two states, the transmitted wave polarization and angle of refraction are different. One could then switch the direction of propagation of the electromagnetic wave and its polarization with a “thin film”, whose thickness ...

  15. Polarization rotation by an rf-SQUID metasurface

    OpenAIRE

    Caputo, J. -G.; Gabitov, I.; Maimistov, A. I.

    2015-01-01

    We study the transmission and reflection of a plane electromagnetic wave through a two dimensional array of rf-SQUIDs. The basic equations describing the amplitudes of the magnetic field and current in the split-ring resonators are developed. These yield in the linear approximation the reflection and transmission coefficients. The polarization of the reflected wave is independent of the frequency of the incident wave and of its polarization; it is defined only by the orientation of the split-...

  16. Electromagnetic Field Scattering on rf-SQUID Based Metasurfaces

    Science.gov (United States)

    Raputo, J. G.; Gabitov, I. R.; Kudyshev, Zh.; Kupaev, T.; Maimistov, A. I.

    2015-09-01

    Electromagnetic field scattering on a 2D array of rf-SQUIDs is considered. We show that the scattering changes for large amplitudes of the incident electromagnetic wave; above a critical amplitude, two different refraction states occur (bistability). In particular, for these two states, the transmitted wave polarization and angle of refraction are different. One could then switch the direction of propagation of the electromagnetic wave and its polarization with a "thin film", whose thickness is much smaller than the wavelength.

  17. Dynamic Characteristics of S-band DC SQUID Amplifier

    DEFF Research Database (Denmark)

    Prokopenko, G. V.; Shitov, S. V.; Koshelets, I. L. L. V. P.

    2003-01-01

    A low-noise rf amplifier based on a de SQUID (SQA) has been tested in the frequency range 3.0-4.6 GHz in the open-loop configuration. The following parameters have been measured for the single-stage balanced type SQA at 4.0 GHz: gain (12 +/- 1) dB, 3 dB bandwidth of 500 MHz and noise temperature (1...

  18. Development of RF Sensor Based on Two-cell SQUID

    Science.gov (United States)

    2012-07-01

    public release; distribution is unlimited. where βrf = 2πLI0/Φ0 is the so called SQUID hysteresis parameter [1], and Φa the static flux introduced by...Journal of Applied Physics 109 063915-10 [12] Goppl M, Fragner A, Baur M, Bianchetti R, Filipp S, Fink J M, Leek P J, Puebla G, Steffen L and Wallraff A

  19. Cosmological flux noise and measured noise power spectra in SQUIDs

    Science.gov (United States)

    Beck, Christian

    2016-06-01

    The understanding of the origin of 1/f magnetic flux noise commonly observed in superconducting devices such as SQUIDs and qubits is still a major unsolved puzzle. Here we discuss the possibility that a significant part of the observed low-frequency flux noise measured in these devices is ultimately seeded by cosmological fluctuations. We consider a theory where a primordial flux noise field left over in unchanged form from an early inflationary or quantum gravity epoch of the universe intrinsically influences the phase difference in SQUIDs and qubits. The perturbation seeds generated by this field can explain in a quantitatively correct way the form and amplitude of measured low-frequency flux noise spectra in SQUID devices if one takes as a source of fluctuations the primordial power spectrum of curvature fluctuations as measured by the Planck collaboration. Our theoretical predictions are in excellent agreement with recent low-frequency flux noise measurements of various experimental groups. Magnetic flux noise, so far mainly considered as a nuisance for electronic devices, may thus contain valuable information about fluctuation spectra in the very early universe.

  20. Fabrication and characterization of shunted μ-SQUID

    Science.gov (United States)

    Kumar, Nikhil; Fournier, T.; Courtois, H.; Gupta, Anjan K.

    2014-04-01

    In order to eliminate hysteresis, we have fabricated and characterized niobium based shunted micron size superconducting quantum interference devices (μ-SQUIDs). We find a wide temperature range where these μ-SQUIDs are non-hysteretic in nature and show a very good Ic vs. B oscillations in hysteretic regime and V vs. B oscillations in non-hysteretic regime. Here we report the characteristics of a shunted- μ-SQUID (Wf38LS72D5). In this device we have achieved a large voltage modulation, in non-hysteretic regime, at various temperatures including such as 1.1 mV at 6.62 K with a transfer function VΦ = 7.2mV/Φ0. The figures within the original article PDF file, as supplied to AIP Publishing, were affected by a PDF-processing error. Consequently, the article re-flowed and pagination increased from 3 to 4 pages. This article was updated on 14 May 2014 to correct the PDF-processing error, with the scientific content remaining unchanged. Readers are advised that the replacement article PDF file contains an additional blank page to preserve the original pagination.

  1. SQUID-based noise thermometer for sub-Millikelvin refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Marco; Beyer, Joern; Klemm, Monique [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany); Alivaliollahi, Sassan; Barthelmess, Henry [Magnicon GmbH, Barkhausenweg 11, 22339 Hamburg (Germany)

    2015-07-01

    The magnetic field fluctuation thermometer (MFFT) is a high-accuracy SQUID-based noise thermometer suitable for sub-Kelvin thermometry. A highly sensitive low-Tc SQUID magnetometer detects inductively the magnetic field fluctuation above a metal surface. The fluctuations are generated by the thermal activated noise currents inside the metal body that is thermally anchored to the temperature stage to be measured. The spectral shape is independent of temperature as the electrical conductivity is constant and the geometry is fixed. The magnetic noise power spectral amplitudes at any frequencies are directly proportional to temperature. Hence, only one reference measurement at a known temperature is required for calibration. A complete MFFT thermometer system for the temperature range of ca. 4 K down to <10 mK is commercially available. We have now developed an integrated MFFT with an extended range of operation down to <1 mK. For this purpose the sensitivity of the SQUID sensor has been increased, the metal body geometry modified and the magnetic shielding of the MFFT module improved. These modifications make it possible to obtain a thermometer noise temperature of <10 μK. We discuss the rationale for our MFFT configuration and present numerical simulations and experimental results.

  2. The radio-frequency HTS SQUID for magnetic microscopy

    CERN Document Server

    Khvostov, S S; Garbuz, A S; Shnyrkov, V I

    2003-01-01

    The spectral density of magnetic flux noise S subPHI sup 1 sup / sup 2 (f) for HTS RF SQUIDs with a pumping frequency of 390-457 Mhz within triple-layer permalloy and superconducting shields are investigated. The superconducting interferometers of 100 centre dot 100 mm, are fabricated by the thin film technology with ramp-edge type Josephson junctions YBaCuO-PrBaCuO-YBaCuO. It is shown that with a cooled preamplifier the energy resolution of SQUIDs makes up to 4 centre dot 10 sup - sup 3 sup 0 J/Hz at 'white' noise (at frequencies above 1 kHz) and is mainly defined by inherent noise of the HTS interferometer and the shields. At low frequencies the noises related to exterior fields that penetrate directly into the shields, are dominant. At frequencies above 1 kHz, the ferromagnetic antenna of the SQUID microscope increases the intrinsic noise of the magnetometer up to 8 centre dot 10 sup - sup 3 sup 0 J/Hz.

  3. Sensitive dc SQUIDs for detection of small spin systems

    Energy Technology Data Exchange (ETDEWEB)

    Woelbing, R.; Nagel, J.; Kemmler, M.; Konovalenko, K.; Turad, M.; Werner, R.; Kleiner, R.; Koelle, D. [Physikalisches Institut - Experimentalphysik II and Center for Collective Quantum Phenomena, Universitaet Tuebingen (Germany); Kieler, O.; Weimann, T.; Kohlmann, J.; Zorin, A. [Fachbereich 2.4 ' ' Quantenelektronik' ' , Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Kleisz, E.; Menzel, S.; Buechner, B.; Klingeler, R. [Leibniz-Institut fuer Festkoerper- und Werkstoffforschung (IFW) Dresden (Germany)

    2011-07-01

    Investigation on small spin systems, e.g. macromolecules, require ultrasensitive devices for sensing the magnetization reversal of such particles with the ultimate goal of single spin flip detection. For this purpose we examine submicron dimension SQUIDs, which can detect the magnetization reversal of small spin particles directly in strong magnetic fields. We fabricated dc SQUIDs based on Nb/HfTi/Nb Josephson junctions with areas down to 200 nm x 200 nm, as well as on YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) grain boundary junctions (GBJs) with linewidths down to 80 nm. The critical current densities for both types of junctions are relatively large (j{sub c}>10{sup 5}A/cm{sup 2} at 4.2 K), which provides high critical currents even for submicron sized junctions. The Nb/HfTi/Nb and the YBCO SQUIDs have been characterized by electric transport and noise measurements at low and high fields up to the tesla range, showing low noise performance.

  4. Low-frequency nuclear quadrupole resonance with a dc SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Chang, J.W.

    1991-07-01

    Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region have traditionally been difficult or unfeasible to detect. This work describes the development and application of a SQUID NQR technique which is capable of measuring intermediate strength quadrupolar interactions, in the range of a few hundred kilohertz to several megahertz. In this technique, a dc SQUID (Superconducting QUantum Interference Device) is used to monitor the longitudinal sample magnetization, as opposed to the transverse magnetization, as a rf field is swept in frequency. This allows the detection of low-frequency nuclear quadrupole resonances over a very wide frequency range with high sensitivity. The theory of this NQR technique is discussed and a description of the dc SQUID system is given. In the following chapters, the spectrometer is discussed along with its application to the study of samples containing half-odd-integer spin quadrupolar nuclei, in particular boron-11 and aluminum-27. The feasibility of applying this NQR technique in the study of samples containing integer spin nuclei is discussed in the last chapter. 140 refs., 46 figs., 6 tabs.

  5. SQUID-based instrumentation for ultralow-field MRI

    Energy Technology Data Exchange (ETDEWEB)

    Zotev, Vadim S; Matlashov, Andrei N; Volegov, Petr L; Urbaitis, Algis V; Espy, Michelle A; Jr, Robert H Kraus [Los Alamos National Laboratory, Group of Applied Modern Physics, MS D454, Los Alamos, NM 87545 (United States)

    2007-11-15

    Magnetic resonance imaging at ultralow fields (ULF MRI) is a promising new imaging method that uses SQUID sensors to measure the spatially encoded precession of pre-polarized nuclear spin populations at a microtesla-range measurement field. In this work, a seven-channel SQUID system designed for simultaneous 3D ULF MRI and magnetoencephalography (MEG) is described. The system includes seven second-order SQUID gradiometers characterized by magnetic field resolutions of 1.2-2.8 fT Hz{sup -1/2}. It is also equipped with five sets of coils for 3D Fourier imaging with pre-polarization. Essential technical details of the design are discussed. The system's ULF MRI performance is demonstrated by multi-channel 3D images of a preserved sheep brain acquired at 46 {mu}T measurement field with pre-polarization at 40 mT. The imaging resolution is 2.5 mm x 2.5 mm x 5 mm. The ULF MRI images are compared to images of the same brain acquired using conventional high-field MRI. Different ways to improve imaging SNR are discussed.

  6. Low-frequency nuclear quadrupole resonance with a dc SQUID

    Science.gov (United States)

    Chang, J. W.

    1991-07-01

    Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region are traditionally difficult or unfeasible to detect. This work describes the development and application of a SQUID NQR technique which is capable of measuring intermediate strength quadrupolar interactions, in the range of a few hundred kilohertz to several megahertz. In this technique, a dc SQUID (Superconducting QUantum Interference Device) is used to monitor the longitudinal sample magnetization, as opposed to the transverse magnetization, as a RF field is swept in frequency. This allows the detection of low-frequency nuclear quadrupole resonances over a very wide frequency range with high sensitivity. The theory of this NQR technique is discussed and a description of the dc SQUID system is given. In the following chapters, the spectrometer is discussed along with its application to the study of samples containing half-odd-integer spin quadrupolar nuclei, in particular boron-11 and aluminum-27. The feasibility of applying this NQR technique in the study of samples containing integer spin nuclei is discussed in the last chapter.

  7. Fabrication and characterization of shunted μ-SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Nikhil, E-mail: knikhil@iitk.ac.in [Department of Physics, Indian Institute of Technology Kanpur - 208016 (India); Fournier, T.; Courtois, H.; Gupta, Anjan K. [Institute Neel, CNRS and Université Joseph Fourier, 25 Avenue des Martyrs, BP 166, 38042, Grenoble (France)

    2014-04-24

    In order to eliminate hysteresis, we have fabricated and characterized niobium based shunted micron size superconducting quantum interference devices (μ-SQUIDs). We find a wide temperature range where these μ-SQUIDs are non-hysteretic in nature and show a very good I{sub c} vs. B oscillations in hysteretic regime and V vs. B oscillations in non-hysteretic regime. Here we report the characteristics of a shunted- μ-SQUID (Wf38LS72D5). In this device we have achieved a large voltage modulation, in non-hysteretic regime, at various temperatures including such as 1.1 mV at 6.62 K with a transfer function V{sub Φ} = 7.2mV/Φ{sub 0}. The figures within the original article PDF file, as supplied to AIP Publishing, were affected by a PDF-processing error. Consequently, the article re-flowed and pagination increased from 3 to 4 pages. This article was updated on 14 May 2014 to correct the PDF-processing error, with the scientific content remaining unchanged. Readers are advised that the replacement article PDF file contains an additional blank page to preserve the original pagination.

  8. Trophic niche of squids: Insights from isotopic data in marine systems worldwide

    Science.gov (United States)

    Navarro, Joan; Coll, Marta; Somes, Christoper J.; Olson, Robert J.

    2013-10-01

    Cephalopods are an important prey resource for fishes, seabirds, and marine mammals, and are also voracious predators on crustaceans, fishes, squid and zooplankton. Because of their high feeding rates and abundance, squids have the potential to exert control on the recruitment of commercially important fishes. In this review, we synthesize the available information for two intrinsic markers (δ15N and δ13C isotopic values) in squids for all oceans and several types of ecosystems to obtain a global view of the trophic niches of squids in marine ecosystems. In particular, we aimed to examine whether the trophic positions and trophic widths of squid species vary among oceans and ecosystem types. To correctly compare across systems, we adjusted squid δ15N values for the isotopic variability of phytoplankton at the base of the food web provided by an ocean circulation-biogeochemistry-isotope model. Studies that focused on the trophic ecology of squids using isotopic techniques were few, and most of the information on squids was from studies on their predators. Our results showed that squids occupy a large range of trophic positions and exploit a large range of trophic resources, reflecting the versatility of their feeding behavior and confirming conclusions from food-web models. Clear differences in both trophic position and trophic width were found among oceans and ecosystem types. The study also reinforces the importance of considering the natural variation in isotopic values when comparing the isotopic values of consumers inhabiting different ecosystems.

  9. Analysis of the ac SQUID with low inductance and low critical current

    DEFF Research Database (Denmark)

    Sørensen, O. H.

    1976-01-01

    The properties of the ac SQUID magnetometer has been analyzed. The results are valid in the low-inductance low-critical-current regime, where the Lri0 producted is belowthe value at which the relation between the enclosed and externally applied magnetic dc flux becomes reentrant. The effects...... of the screening current circulating in the SQUID ring as well as of the SQUID-ring time constant, tau-Lr/R9 are taken into account. Here LR IS THE SQUID-ring inductance, and R is the shunt resistance in the shunted junction model assumed to describe the weak link. It is shown that for finite values of omegatau...

  10. Tuning an rf-SQUID flux qubit system's potential with magnetic flux bias

    Institute of Scientific and Technical Information of China (English)

    Hua Tao; Xu Wei-Wei; Shi Jian-Xin; An De-Yue; Sun Guo-Zhu; Yu Yang; Wu Pei-Heng

    2012-01-01

    At an extremely low temperature of 20 mK,we measured the loop current in a tunable rf superconducting quantum interference device (SQUID) with a dc-SQUID.By adjusting the magnetic flux applied to the rf-SQUID loop (φf) and the small dc-SQUID (φcjjf),respectively,the potential shape of the system can be fully controlled in situ.Variation in the transition step and overlap size in the switching current with a barrier flux bias are analyzed,from which we can obtain some relevant device parameters and build a model to explain the experimental phenomenon.

  11. Basic properties of an rf SQUID involving two Josephson junctions connected in series

    Institute of Scientific and Technical Information of China (English)

    Mao Bo; Tan Zhong-Kui; Meng Shu-Chao; Dai Yuan-Dong; Wang Fu-Ren

    2004-01-01

    We have studied the basic characteristics of a radio frequency superconducting quantum interference device (rf SQUID) involving two Josephson junctions connected in series, the case for the widely used grain boundary junction (GBJ) rf SQUID. It is found that the SQUID properties are determined mainly by the weaker junction when the critical current of the weaker junction is much lower than that of the other junction. Otherwise, the effect of the other junction is not negligible. We also find that only when the hysteresis parameter β is less than 1- α, where α is the critical current ratio of the two junctions, will the SQUID operate in the nonhysteretic mode.

  12. Detecting defect in cast iron using high-T{sub C} SQUID

    Energy Technology Data Exchange (ETDEWEB)

    He, D.F.; Yoshizawa, M.; Oyama, Y.; Nakamura, M

    2004-10-01

    For eddy-current NDE, due to the big permeability of ferromagnetic material, low testing frequency is needed to detect defects in it. SQUID has advantages in low frequency eddy current NDE. But the large magnetic field produced by ferromagnetic material often exceeds the dynamic range of general SQUID system. We developed a mobile high-T{sub C} SQUID system, with which, the dc and low-frequency magnetic field could be compensated well. Using our mobile SQUID system, the magnetic field produced by the cast iron could be compensated well and the defect in it could be successfully detected.

  13. SQUID detected NMR and NQR. Superconducting Quantum Interference Device.

    Science.gov (United States)

    Augustine, M P; TonThat, D M; Clarke, J

    1998-03-01

    The dc Superconducting QUantum Interference Device (SQUID) is a sensitive detector of magnetic flux, with a typical flux noise of the order 1 muphi0 Hz(-1/2) at liquid helium temperatures. Here phi0 = h/2e is the flux quantum. In our NMR or NQR spectrometer, a niobium wire coil wrapped around the sample is coupled to a thin film superconducting coil deposited on the SQUID to form a flux transformer. With this untuned input circuit the SQUID measures the flux, rather than the rate of change of flux, and thus retains its high sensitivity down to arbitrarily low frequencies. This feature is exploited in a cw spectrometer that monitors the change in the static magnetization of a sample induced by radio frequency irradiation. Examples of this technique are the detection of NQR in 27Al in sapphire and 11B in boron nitride, and a level crossing technique to enhance the signal of 14N in peptides. Research is now focused on a SQUID-based spectrometer for pulsed NQR and NMR, which has a bandwidth of 0-5 MHz. This spectrometer is used with spin-echo techniques to measure the NQR longitudinal and transverse relaxation times of 14N in NH4ClO4, 63+/-6 ms and 22+/-2 ms, respectively. With the aid of two-frequency pulses to excite the 359 kHz and 714 kHz resonances in ruby simultaneously, it is possible to obtain a two-dimensional NQR spectrum. As a third example, the pulsed spectrometer is used to study NMR spectrum of 129Xe after polariza-tion with optically pumped Rb. The NMR line can be detected at frequencies as low as 200 Hz. At fields below about 2 mT the longitudinal relaxation time saturates at about 2000 s. Two recent experiments in other laboratories have extended these pulsed NMR techniques to higher temperatures and smaller samples. In the first, images were obtained of mineral oil floating on water at room temperature. In the second, a SQUID configured as a thin film gradiometer was used to detect NMR in a 50 microm particle of 195Pt at 6 mT and 4.2 K.

  14. Polyphyly of non-bioluminescent Vibrio fischeri sharing a lux-locus deletion.

    Science.gov (United States)

    Wollenberg, M S; Preheim, S P; Polz, M F; Ruby, E G

    2012-03-01

    This study reports the first description and molecular characterization of naturally occurring, non-bioluminescent strains of Vibrio fischeri. These 'dark' V. fischeri strains remained non-bioluminescent even after treatment with both autoinducer and aldehyde, substrate additions that typically maximize light production in dim strains of luminous bacteria. Surprisingly, the entire lux locus (eight genes) was absent in over 97% of these dark V. fischeri strains. Although these strains were all collected from a Massachusetts (USA) estuary in 2007, phylogenetic reconstructions allowed us to reject the hypothesis that these newly described non-bioluminescent strains exhibit monophyly within the V. fischeri clade. These dark strains exhibited a competitive disadvantage against native bioluminescent strains when colonizing the light organ of the model V. fischeri host, the Hawaiian bobtail squid Euprymna scolopes. Significantly, we believe that the data collected in this study may suggest the first observation of a functional, parallel locus-deletion event among independent lineages of a non-pathogenic bacterial species.

  15. Multiplexed Readout of MMC Detector Arrays Using Non-hysteretic rf-SQUIDs

    Science.gov (United States)

    Kempf, S.; Wegner, M.; Gastaldo, L.; Fleischmann, A.; Enss, C.

    2014-08-01

    Metallic magnetic calorimeters (MMCs) are widely used for various experiments in fields ranging from atomic and nuclear physics to X-ray spectroscopy, laboratory astrophysics or material science. Whereas in previous experiments single pixel detectors or small arrays have been used, for future applications large arrays are needed. Therefore, suitable multiplexing techniques for MMC arrays are currently under development. A promising approach for the readout of large arrays is the microwave SQUID multiplexer that employs non-hysteretic rf-SQUIDs to create a frequency shift of high resonators that is in accordance with the detector signal and that can be monitored by using standard microwave measurement techniques. In this paper we discuss the design of a recently developed and fabricated 64 pixel detector array with integrated microwave SQUID multiplexer that was produced to test the suitability of this readout technique. The characterization of dc-SQUIDs with virtually identical washer design compared to the rf-SQUIDs of the SQUID multiplexer revealed that the crucial SQUID parameters such as the critical current of the Josephson junctions or the washer inductance are close to the design values and anticipates a successful operation of the SQUID multiplexer.

  16. A YBCO RF-squid variable temperature susceptometer and its applications

    Science.gov (United States)

    Zhou, Luwei; Qiu, Jinwu; Zhang, Xianfeng; Tang, Zhimin; Cai, Yimin; Qian, Yongjia

    1991-01-01

    The Superconducting QUantum Interference Device (SQUID) susceptibility using a high-temperature radio-frequency (rf) SQUID and a normal metal pick-up coil is employed in testing weak magnetization of the sample. The magnetic moment resolution of the device is 1 x 10(exp -6) emu, and that of the susceptibility is 5 x 10(exp -6) emu/cu cm.

  17. Construction and test of a cryocooler-cooled low-Tc SQUID gradiometer system

    NARCIS (Netherlands)

    Rijpma, A.P.; Krooshoop, H.J.G.; Lefevere, M.W.; Leeuwen, van E.P.; Holland, H.J.; Haken, ten B.; Brake, ter H.J.M.

    2008-01-01

    A cryocooler-cooled low-Tc SQUID gradiometer system was designed and constructed. It is based on a 4 K GM-cooler that is positioned several meters from the measuring head containing the SQUID sensors. The cooling power is transported by means of a circulating helium flow. Thus, there are three main

  18. SQUID-magnetometer with open-ended horizontal room-temperature access

    NARCIS (Netherlands)

    Brake, ter H.J.M.; Ulfman, J.A.; Flokstra, J.

    1984-01-01

    A new, SQUID-based magnetometer has been developed for measurements of remanent and induced magnetisation. The advantage of this system compared to conventional SQUID-magnetometers is its horizontal access to the sensing coils. The access at room temperature is open at both ends. Main benefits of th

  19. Multi-terminal multi-junction dc SQUID for nanoscale magnetometry

    Science.gov (United States)

    Meltzer, Alexander Y.; Uri, Aviram; Zeldov, Eli

    2016-11-01

    Miniaturization of superconducting quantum interference devices (SQUIDs) is of major importance for the development of sensitive scanning nanoscale magnetometry tools. The high sensitivity of nanoSQUIDs is restricted, however, to only particular periodic values of the applied magnetic field, making accurate measurements at intermediate values of the field impossible. We present a theoretical investigation of a multi-terminal, multi-junction SQUID (mSQUID) that lifts this limitation by providing electrical means for a continuous shift of the quantum interference pattern with respect to the applied field. Analysis of 4-terminal, 4-junction and 3-terminal, 3-junction mSQUIDs shows that operation at maximum sensitivity can be obtained at any value of the magnetic field by applying control current to the extra terminals. The model describes the variation and the shift of the interference pattern as a function of the control currents, junction asymmetries, and the mSQUID inductance. The mSQUID is also shown to provide a direct measurement of the current-phase relations of superconducting junctions. The derived model provides a quantitative description of the recently developed multi-terminal nanoSQUID-on-tip.

  20. 77 FR 22678 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2012-04-17

    ... National Oceanic and Atmospheric Administration 50 CFR Part 648 RIN 0648- XB145 Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the Trimester 1 Longfin Squid Fishery AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and...

  1. FORMED SEMI-FINISHED PRODUCTS FROM SQUID FORCEMEAT. INVESTIGATION OF THE FUNCTIONAL AND TECHNOLOGICAL PROPERTIES OF FORCEMEAT MIXTURE

    Directory of Open Access Journals (Sweden)

    Ivchenkova E. N.

    2014-09-01

    Full Text Available The influence of addition of boiled forcemeat of a squid to raw forcemeat on functional and technological properties of forcemeat is investigated. The formulation of forcemeat for formed semi-finished products of squid is presented. Periods of storage of formed semi-finished products of squid are substantiated

  2. Quantum analysis of a nonlinear microwave cavity-embedded dc SQUID displacement detector

    Science.gov (United States)

    Nation, P. D.; Blencowe, M. P.; Buks, E.

    2008-09-01

    We carry out a quantum analysis of a dc superconducting quantum interference device (SQUID) mechanical displacement detector, comprising a SQUID with mechanically compliant loop segment, which is embedded in a microwave transmission line resonator. The SQUID is approximated as a nonlinear current-dependent inductance, inducing an external flux tunable nonlinear Duffing self-interaction term in the microwave resonator mode equation. Motion of the compliant SQUID loop segment is transduced inductively through changes in the external flux threading SQUID loop, giving a ponderomotive radiation pressure-type coupling between the microwave and mechanical resonator modes. Expressions are derived for the detector signal response and noise, and it is found that a soft-spring Duffing self-interaction enables a closer approach to the displacement detection standard quantum limit, as well as cooling closer to the ground state.

  3. Electromagnetic Field Scattering on rf-SQUID Based Metasurfaces

    Directory of Open Access Journals (Sweden)

    Сaputo J.G

    2015-01-01

    Full Text Available Electromagnetic field scattering on a 2D array of rf-SQUIDs is considered. We show that the scattering changes for large amplitudes of the incident electromagnetic wave; above a critical amplitude, two different refraction states occur (bistability. In particular, for these two states, the transmitted wave polarization and angle of refraction are different. One could then switch the direction of propagation of the electromagnetic wave and its polarization with a “thin film”, whose thickness is much smaller than the wavelength.

  4. Issues relating to airborne applications of HTS SQUIDs

    CERN Document Server

    Foley, C P; Binks, R A; Lam, S H K; Du, J; Tilbrook, D L; Mitchell, E E; MacFarlane, J C; Lee, J B; Turner, R; Downey, M; Maddever, A

    2002-01-01

    Airborne application of HTS SQUIDs is the most difficult environment for their successful deployment. In order to operate with the sensitivity required for a particular application, there are many issues to be addressed such as the need for very wide dynamic range electronics, motion noise elimination, immunity to large changing magnetic fields and cultural noise sources. This paper reviews what is necessary to achieve an airborne system giving examples in geophysical mineral exploration. It will consider issues relating to device design and fabrication, electronics, dewar design, suspension system requirements and noise elimination methods.

  5. Optimal configuration of receiving coils of SQUID-magnetometer

    CERN Document Server

    Ishikaev, S M

    2002-01-01

    Paper describes a SQUID-magnetometer receiving system based on the second order symmetric gradiometer. Four series connected coils of a superconducting transformer consisting of one niobium-titanium wire turn are cemented onto dewar outside. Due to signal compensation in all coils the given receiving system is unsusceptible to signal from specimen holder and it improves measurement accuracy. Using the described magnetometer one managed to observe abrupt changes of magnetization curves of a 100 x 100 cell square superconducting grid with the Josephson tunnel transitions

  6. Squid Pen Chitin Chitooligomers as Food Colorants Absorbers

    OpenAIRE

    Tzu-Wen Liang; Chih-Ting Huang; Nguyen Anh Dzung; San-Lang Wang

    2015-01-01

    One of the most promising applications of chitosanase is the conversion of chitinous biowaste into bioactive chitooligomers (COS). TKU033 chitosanase was induced from squid pen powder (SPP)-containing Bacillus cereus TKU033 medium and purified by ammonium sulfate precipitation and column chromatography. The enzyme was relatively more thermostable in the presence of the substrate and had an activity of 93% at 50 °C in a pH 5 buffer solution for 60 min. Furthermore, the enzyme used for the COS ...

  7. Magnetic resonance spectrometer with a dc SQUID detector

    Science.gov (United States)

    Connor, C.; Chang, J.; Pines, A.

    1990-03-01

    We describe a dc superconducting quantum interference device (SQUID) based magnetic resonance spectrometer particularly suited to measurements in the frequency range of 100 kHz to several megahertz. Results are presented for nuclear quadrupole resonance (NQR) of boron-11 in boron nitride at 4.2 K, yielding ωQ =1467±2 kHz. We also present a direct measurement of the methyl group tunneling frequency, ωt =210±10 kHz, of propionic acid in low field, at 4.2 K.

  8. Determining the vibrations between sensor and sample in SQUID microscopy

    Science.gov (United States)

    Schiessl, Daniel; Kirtley, John R.; Paulius, Lisa; Rosenberg, Aaron J.; Palmstrom, Johanna C.; Ullah, Rahim R.; Holland, Connor M.; Fung, Y.-K.-K.; Ketchen, Mark B.; Gibson, Gerald W.; Moler, Kathryn A.

    2016-12-01

    Vibrations can cause noise in scanning probe microscopies. Relative vibrations between the scanning sensor and the sample are important but can be more difficult to determine than absolute vibrations or vibrations relative to the laboratory. We measure the noise spectral density in a scanning SQUID microscope as a function of position near a localized source of magnetic field and show that we can determine the spectra of all three components of the relative sensor-sample vibrations. This method is a powerful tool for diagnosing vibrational noise in scanning microscopies.

  9. Assessing the trophic position and ecological role of squids in marine ecosystems by means of food-web models

    Science.gov (United States)

    Coll, Marta; Navarro, Joan; Olson, Robert J.; Christensen, Villy

    2013-10-01

    We synthesized available information from ecological models at local and regional scales to obtain a global picture of the trophic position and ecological role of squids in marine ecosystems. First, static food-web models were used to analyze basic ecological parameters and indicators of squids: biomass, production, consumption, trophic level, omnivory index, predation mortality diet, and the ecological role. In addition, we developed various dynamic temporal simulations using two food-web models that included squids in their parameterization, and we investigated potential impacts of fishing pressure and environmental conditions for squid populations and, consequently, for marine food webs. Our results showed that squids occupy a large range of trophic levels in marine food webs and show a large trophic width, reflecting the versatility in their feeding behaviors and dietary habits. Models illustrated that squids are abundant organisms in marine ecosystems, and have high growth and consumption rates, but these parameters are highly variable because squids are adapted to a large variety of environmental conditions. Results also show that squids can have a large trophic impact on other elements of the food web, and top-down control from squids to their prey can be high. In addition, some squid species are important prey of apical predators and may be keystone species in marine food webs. In fact, we found strong interrelationships between neritic squids and the populations of their prey and predators in coastal and shelf areas, while the role of squids in open ocean and upwelling ecosystems appeared more constrained to a bottom-up impact on their predators. Therefore, large removals of squids will likely have large-scale effects on marine ecosystems. In addition, simulations confirm that squids are able to benefit from a general increase in fishing pressure, mainly due to predation release, and quickly respond to changes triggered by the environment. Squids may thus

  10. Impact of SQUIDs on functional imaging in neuroscience

    Science.gov (United States)

    Della Penna, Stefania; Pizzella, Vittorio; Romani, Gian Luca

    2014-04-01

    This paper provides an overview on the basic principles and applications of magnetoencephalography (MEG), a technique that requires the use of many SQUIDs and thus represents one of the most important applications of superconducting electronics. Since the development of the first SQUID magnetometers, it was clear that these devices could be used to measure the ultra-low magnetic signals associated with the bioelectric activity of the neurons of the human brain. Forty years on from the first measurement of magnetic alpha rhythm by David Cohen, MEG has become a fundamental tool for the investigation of brain functions. The simple localization of cerebral sources activated by sensory stimulation performed in the early years has been successively expanded to the identification of the sequence of neuronal pool activations, thus decrypting information of the hierarchy underlying cerebral processing. This goal has been achieved thanks to the development of complex instrumentation, namely whole head MEG systems, allowing simultaneous measurement of magnetic fields all over the scalp with an exquisite time resolution. The latest trends in MEG, such as the study of brain networks, i.e. how the brain organizes itself in a coherent and stable way, are discussed. These sound applications together with the latest technological developments aimed at implementing systems able to record MEG signals and magnetic resonance imaging (MRI) of the head with the same set-up pave the way to high performance systems for brain functional investigation in the healthy and the sick population.

  11. An analysis of conductance changes in squid axon.

    Science.gov (United States)

    MULLINS, L J

    1959-05-20

    The membrane of the squid axon is considered on the basis of a pore model in which the distribution of the pore sizes strongly favors K(+) transfer when there is no potential. Electrical asymmetry causes non-penetrating ions on the membrane capacitor to exert a mechanical force on both membrane surfaces and this force results in a deformation of the membrane pore system such that it assumes a distribution of sizes favoring the ions exerting mechanical force. The ions involved appear to be Ca(++) on the outside of the membrane and isethionate(-), (i(-)) on the inside; as Ca(++) is equivalent in size to Na(+), the charged membrane is potentially able to transfer Na(+), when the ions deforming the membrane pore distribution are removed. A depolarization of the membrane leads to an opening of pores that will allow Na(+) penetration and a release of the membrane from deformation. The pores revert to the zero-potential pore size distribution hence the Na permeability change is a transient. Calculation shows that the potassium conductance vs. displacement of membrane potential curve for the squid axon and the "inactivation" function, h, can be obtained directly from the assumed membrane distortion without the introduction of arbitrary parameters. The sodium conductance, because it is a transient, requires assumptions about the time constants with which ions unblock pores at the outside and the inside of the membrane.

  12. Scanning SQUID microscopy of local superconductivity in inhomogeneous combinatorial ceramics.

    Science.gov (United States)

    Iranmanesh, Mitra; Stir, Manuela; Kirtley, John R; Hulliger, Jürg

    2014-11-24

    Although combinatorial solid-state chemistry promises to be an efficient way to search for new superconducting compounds, the problem of determining which compositions are strongly diamagnetic in a mixed-phase sample is challenging. By means of reactions in a system of randomly mixed starting components (Ca, Sr, Ba, La, Y, Pb, Bi, Tl, and Cu oxides), samples were produced that showed an onset of diamagnetic response above 115 K in bulk measurements. Imaging of this diamagnetic response in ceramic samples by scanning SQUID microscopy (SSM) revealed local superconducting areas with sizes down to as small as the spatial resolution of a few micrometers. In addition, locally formed superconducting matter was extracted from mixed-phase samples by magnetic separation. The analysis of single grains (d<80 μm) by X-ray diffraction, elemental analysis, and bulk SQUID measurements allowed Tl2Ca3Ba2Cu4O12, TlCaBaSrCu2O(7-δ), BaPb(0.5)Bi(0.25)Tl(0.25)O(3-δ), TlBa2Ca2Cu3O9, Tl2Ba2CaCu2O8, and YBa2Cu3O7 phases to be identified. SSM, in combination with other diagnostic techniques, is therefore shown to be a useful instrument to analyze inhomogeneous reaction products in the solid-state chemistry of materials showing magnetic properties.

  13. Sensitive YBCO nanoSQUIDs for the investigation of small spin systems

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Benedikt; Schwarz, Tobias; Woelbing, Roman; Martinez-Perez, Maria Jose; Kleiner, Reinhold; Koelle, Dieter [Tuebingen Univ. (Germany). Physikalisches Inst. and Center for Collective Quantum Phenomena in LISA+; Reiche, Christopher F.; Muehl, Thomas; Buechner, Bernd [Leibniz Institute for Solid State and Materials Research IFW Dresden (Germany)

    2015-07-01

    We report on advances in the realization of dc YBCO nanoSQUIDs for continuous measurement of magnetic nanoparticle magnetization loops in strong magnetic fields up to the Tesla range, applied in the plane of the SQUID loop at temperatures of 4 K and below. Our grain boundary junction based YBCO SQUIDs are patterned by focused ion beam milling and feature a constriction next to the SQUID loop, allowing for on-chip SQUID modulation and bias reversal readout schemes. Using numerical simulations based on London theory, the spin sensitivity S{sub μ}{sup 1/2} = S{sub Φ}{sup 1/2} / φ{sub μ} was improved by optimizing both the flux noise S{sub Φ}{sup 1/2} and the coupling factor φ{sub μ} = Φ / μ (Φ is the magnetic flux coupled into the SQUID loop by a particle with magnetic moment μ). For optimized experimental devices, flux noise levels down to 50 nΦ{sub 0} / Hz{sup 1/2} in the white noise limit have been achieved, corresponding to a calculated spin sensitivity of only a few μ{sub B} / Hz{sup 1/2}. Further, the magnetization reversal of a Fe filled carbon nanotube attached to a YBCO nanoSQUID was traced out.

  14. The fabrication and characterization of nano-SQUIDs based on Nb thin films

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xixi; Liu, Xiaoyu; Wang, Hao; Chen, Lei, E-mail: leichen@mail.sim.ac.cn; Wang, Zhen

    2015-08-15

    Highlights: • We developed a nano-SQUID fabrication process starting from a high-quality thin film. • The fabricated nano-SQUIDs exhibited flux modulation depth up to 10.3% at 4.6 K. • The measured data agreed with the Ginzburg–Landau simulation. • We found that a small critical current <50 μA is important for a deep flux modulation. • The suggestions in improving the nano-SQUID’s performance were discussed. - Abstract: SQUIDs with nano-junctions (or nano-SQUIDs) are able to be miniaturized into nanoscale to measure a single Bohr magneton. Here, we reported the development of a fabrication process for Nb (niobium) nano-SQUIDs using the thin film deposition and the electron-beam lithography technology. The developed process started from a high-quality superconducting thin film so that it is compatible with a variety of film growing techniques. The as-fabricated nano-SQUIDs exhibited functional flux modulation depth up to 10.3% at 4.6 K, in agreement with the numerical simulation based on the Ginzburg–Landau equation. By further comparing the results from both experiments and simulations, we found that a small critical current below ∼50 μA played a leading role in order to obtain a decent flux-modulation depth for Nb nano-SQUIDs.

  15. In vitro antioxidant, antimutagenic and antiproliferative activities of collagen hydrolysates of jumbo squid (Dosidicus gigas byproducts

    Directory of Open Access Journals (Sweden)

    Guadalupe Miroslava Suárez-Jiménez

    2015-09-01

    Full Text Available AbstractHydrolysates from two different jumbo squid byproducts (fins and arms, produced by trypsin and protease type XIV were compared on the basis of their antioxidant (DPPH and ABTS radical scavenging assays, antimutagenic (Ames test and antiproliferative (Transformation cell proliferation in M12.C3F6 murine cells activities. Jumbo squid arms had higher content of collagen than fins, and their hydrolysates had the highest antioxidant activity. Also, jumbo squid arm-derived collagen hydrolyzed with protease XIV showed the highest antimutagenic activity. The four hydrolysates obtained showed low antiproliferative activity, however they are susceptible for further studies to be applied as food additives.

  16. A SQUID-based microwave cavity search for dark-matter axions

    Energy Technology Data Exchange (ETDEWEB)

    Asztalos, S J; Carosi, G; Hagmann, C; Kinion, D; van Bibber, K; Hotz, M; Rosenberg, L; Rybka, G; Hoskins, J; Hwang, J; Sikivie, P; Tanner, D B; Bradley, R; Clarke, J

    2009-10-21

    Axions in the {mu}eV mass range are a plausible cold dark matter candidate and may be detected by their conversion into microwave photons in a resonant cavity immersed in a static magnetic field. The first result from such an axion search using a superconducting first-stage amplifier (SQUID) is reported. The SQUID amplifier, replacing a conventional GaAs field-effect transistor amplifier, successfully reached axion-photon coupling sensitivity in the band set by present axion models and sets the stage for a definitive axion search utilizing near quantum-limited SQUID amplifiers.

  17. Chitinolytic Bacteria-Assisted Conversion of Squid Pen and Its Effect on Dyes and Pigments Adsorption

    OpenAIRE

    Tzu-Wen Liang; Bo-Chang Lo; San-Lang Wang

    2015-01-01

    The aim of this work was to produce chitosanase by fermenting from squid pen, and recover the fermented squid pen for dye removal by adsorption. One chitosanase induced from squid pen powder (SPP)-containing medium by Bacillus cereus TKU034 was purified in high purification fold (441) and high yield of activity recovery (51%) by ammonium sulfate precipitation and combined column chromatography. The SDS-PAGE results showed its molecular mass to be around 43 kDa. The TKU034 chitosanase used for...

  18. A digital filtering scheme for SQUID based magnetocardiography

    Institute of Scientific and Technical Information of China (English)

    Zhu Xue-Min; Ren Yu-Feng; Yu Hong-Wei; Zhao Shi-Ping; Chen Geng-Hua; Zhang Li-Hua; Yang Qian-Sheng

    2006-01-01

    Considering the properties of slow change and quasi-periodicity of magnetocardiography (MCG) signal, we use an integrated technique of adaptive and low-pass filtering in dealing with two-channel MCG data measured by high Tc SQUIDs, The adaptive filter in the time domain is based on a noise feedback normalized least-mean-square (NLMS) algorithm, and the low-pass filter with a cutoff at 100Hz in the frequency domain characterized by Gaussian functions is combined with a notch at the power line frequency. In this way, both relevant and irrelevant noises in original MCG data are largely eliminated. The method may also be useful for other slowly varying quasi-periodical signals.

  19. The Transition from Stiff to Compliant Materials in Squid Beaks

    Science.gov (United States)

    Miserez, Ali; Schneberk, Todd; Sun, Chengjun; Zok, Frank W.; Waite, J. Herbert

    2008-03-01

    The beak of the Humboldt squid Dosidicus gigas represents one of the hardest and stiffest wholly organic materials known. As it is deeply embedded within the soft buccal envelope, the manner in which impact forces are transmitted between beak and envelope is a matter of considerable scientific interest. Here, we show that the hydrated beak exhibits a large stiffness gradient, spanning two orders of magnitude from the tip to the base. This gradient is correlated with a chemical gradient involving mixtures of chitin, water, and His-rich proteins that contain 3,4-dihydroxyphenyl-L-alanine (dopa) and undergo extensive stabilization by histidyl-dopa cross-link formation. These findings may serve as a foundation for identifying design principles for attaching mechanically mismatched materials in engineering and biological applications.

  20. Braking Performance of a Biomimetic Squid-Like Underwater Robot

    Institute of Scientific and Technical Information of China (English)

    Md.Mahbubar Rahman; Sinpei Sugimori; Hiroshi Miki; Risa Yamamoto; Yugo Sanada; Yasuyuki Toda

    2013-01-01

    In this study,the braking performance of the undulating fin propulsion system ofa biomimetic squid-like underwater robot was investigated through free run experiment and simulation of the quasi-steady mathematical model.The quasi-steady equations of motion were solved using the measured and calculated hydrodynamic forces and compared with free-run test results.Various braking strategies were tested and discussed in terms of stopping ability and the forces acting on the stopping stage.The stopping performance of the undulating fin propulsion system tured out to be excellent considering the short stopping time and short stopping distance.This is because of the large negative thrust produced by progressive wave in opposite direction.It was confirmed that the undulating fin propulsion system can effectively perform braking even in complex underwater explorations.

  1. Synchronization of networked Jahn-Teller systems in SQUIDs

    Science.gov (United States)

    Gül, Yusuf

    2016-06-01

    We consider the nonlinear effects in a Jahn-Teller (JT) system of two coupled resonators interacting simultaneously with a flux qubit using coupled SQUIDs. A two-frequency description of JT system that inherits the networked structure of both nonlinear Josephson junctions and harmonic oscillators is employed to describe the synchronous structures in a multifrequency scheme. Eigenvalue spectrum is used to show the switch between the effective single mode and two mode configuration in terms of frequency difference. The Rabi supersplitting is investigated by the spectral response of JT systems in different coupling regimes. Second-order coherence functions are employed to investigate antibunching effects in resonator mode. Synchronous structure between correlations of privileged mode and qubit is obtained in localization-delocalization and photon blockade regime controlled by the population imbalance.

  2. SQUID-Detected Microtesla MRI in the presence of Metal

    Energy Technology Data Exchange (ETDEWEB)

    Moessle, Michael; Han, Song-I.; Myers, Whittier; Lee, Seung-Kyun; Kelso, Nathan; Hatridge, Michael; Pines, Alexander; Clarke, John

    2006-09-06

    In magnetic resonance imaging (MRI) performed at fields of 1 T and above, the presence of a metal insert can distort the image because of susceptibility differences within the sample and modification of the radiofrequency fields by screening currents. Furthermore, it is not feasible to perform nuclear magnetic resonance (NMR) spectroscopy or acquire a magnetic resonance image if the sample is enclosed in a metal container. Both problems can be overcome by substantially lowering the NMR frequency. Using a microtesla imaging system operating at 2.8 kHz, with a superconducting quantum interference device (SQUID) as the signal detector, we have obtained distortion-free images of a phantom containing a titanium bar and three-dimensional images of an object enclosed in an aluminum can; in both cases high-field images are inaccessible.

  3. Multimodal transition and stochastic antiresonance in squid giant axons

    CERN Document Server

    Borkowski, L S

    2010-01-01

    The experimental data of N. Takahashi, Y. Hanyu, T. Musha, R. Kubo, and G. Matsumoto, Physica D \\textbf{43}, 318 (1990), on the response of squid giant axons stimulated by periodic sequence of short current pulses is interpreted within the Hodgkin-Huxley model. The minimum of the firing rate as a function of the stimulus amplitude $I_0$ in the high-frequency regime is due to the multimodal transition. Below this singular point only odd multiples of the driving period remain and the system is highly sensitive to noise. The coefficient of variation has a maximum and the firing rate has a minimum as a function of the noise intensity which is an indication of the stochastic coherence antiresonance. The model calculations reproduce the frequency of occurrence of the most common modes in the vicinity of the transition. A linear relation of output frequency vs. $I_0$ for above the transition is also confirmed.

  4. Detection of Rapid Atrial Arrhythmias in SQUID Magnetocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Woong; Kwon, Hyuk Chan; Kim, Ki Dam; Lee, Yong Ho; Kim, Jin Mok; Kim, In Seon; Lim, Hyun Kyoon; Park, Yong Ki [Biomagnetism Research, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Kim, Doo Sang [Seoul Veterans Hospital, Seoul (Korea, Republic of); Lim, Seung Pyung [Chungnam National University Hospital, Daejeon (Korea, Republic of)

    2005-10-15

    We propose a method to measure atrial arrhythmias (AA) such as atrial fibrillation (Afb) and atrial flutter (Afl) with a SQUID magnetocardiograph (MCG) system. To detect AA is one of challenging topics in MCG. As the AA generally have irregular rhythm and atrio-ventricular conduction, the MCG signal cannot be improved by QRS averaging; therefore a SQUID MCG system having a high SNR is required to measure informative atrial excitation with a single scan. In the case of Afb, diminished f waves are much smaller than normal P waves because the sources are usually located on the posterior wall of the heart. In this study, we utilize an MCG system measuring tangential field components, which is known to be more sensitive to a deeper current source. The average noise spectral density of the whole system in a magnetic shielded room was 10 fT/Hz(a) 1 Hz and 5 fT/Hz(a) 100 Hz. We measured the MCG signals of patients with chronic Afb and Afl. Before the AA measurement, the comparison between the measurements in supine and prone positions for P waves has been conducted and the experiment gave a result that the supine position is more suitable to measure the atrial excitation. Therefore, the AA was measured in subject's supine position. Clinical potential of AA measurement in MCG is to find an aspect of a reentry circuit and to localize the abnormal stimulation noninvasively. To give useful information about the abnormal excitation, we have developed a method, separative synthetic aperture magnetometry (sSAM). The basic idea of sSAM is to visualize current source distribution corresponding to the atrial excitation, which are separated from the ventricular excitation and the Gaussian sensor noises. By using sSAM, we localized the source of an Afl successfully.

  5. Multiplexed readout of MMC detector arrays using non-hysteretic rf-SQUIDs

    CERN Document Server

    Kempf, S; Gastaldo, L; Fleischmann, A; Enss, C

    2013-01-01

    Metallic magnetic calorimeters (MMCs) are widely used for various experiments in fields ranging from atomic and nuclear physics to x-ray spectroscopy, laboratory astrophysics or material science. Whereas in previous experiments single pixel detectors or small arrays have been used, for future applications large arrays are needed. Therefore, suitable multiplexing techniques for MMC arrays are currently under development. A promising approach for the readout of large arrays is the microwave SQUID multiplexer that operates in the frequency domain and that employs non-hysteretic rf-SQUIDs to transduce the detector signals into a frequency shift of high $Q$ resonators which can be monitored by using standard microwave measurement techniques. In this paper we discuss the design and the expected performance of a recently developed and fabricated 64 pixel detector array with integrated microwave SQUID multiplexer. First experimental data were obtained characterizing dc-SQUIDs with virtually identical washer design.

  6. Growth of juvenile shrimp Metapenaeus monoceros fed with squid and mussel

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.; Nair, S.R.S.; Krishnakumari, L.

    Small juveniles of both sexes and females of large juveniles of Metapenaeus monoceros attained faster growth with squid diet. Males of large juveniles registered better growth with mussel diet. No significant difference was observed in moult weights...

  7. Stable High-T {sub c} rf SQUID NDE system operating in noisy environment

    Energy Technology Data Exchange (ETDEWEB)

    He, D.F. [Superconducting Materials Center, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan)]. E-mail: he.dongfeng@nims.go.jp; Yoshizawa, M. [Iwate University, Ueda 4-3-5, Morioka 020-8551 (Japan); Itozaki, H. [Superconducting Materials Center, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan)

    2006-04-15

    A high-T {sub c} rf SQUID NDE system was developed for stable, long time operation in a noisy environment. To reduce the influence of high frequency electromagnetic interference (EMI), a carefully designed metal shielding made of 0.1 mm thick metal foil was used. With the metal shielding, the SQUID could still operate well when a cellular phone was used nearby although the cellular phone could produce very strong EMI noises. To reduce the influence of the line interference or low frequency noises, a compensation method was used in the SQUID-based NDE system. With the compensation, the low frequency and the line interference could be reduced well. Using this SQUID-based NDE system, we successfully performed the NDE measurements in a noisy environment.

  8. 76 FR 39313 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2011-07-06

    ... National Oceanic and Atmospheric Administration 50 CFR Part 648 RIN 0648-XA523 Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the Directed Butterfish Fishery AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and...

  9. SQUID-Detected Magnetic Resonance Imaging in MicroteslaFields

    Energy Technology Data Exchange (ETDEWEB)

    Moessle, Michael; Hatridge, Michael; Clarke, John

    2006-08-14

    amplitude in MRI using laser polarized noble gases such as {sup 3}He or {sup 129}Xe (10-12). Hyperpolarized gases were used successfully to image the human lung in fields on the order of several mT (13-15). To overcome the sensitivity loss of Faraday detection at low frequencies, ultrasensitive magnetometers based on the Superconducting QUantum Interference Device (SQUID) (16) are used to detect NMR and MRI signals (17-24). Recently, SQUID-based MRI systems capable of acquiring in vivo images have appeared. For example, in the 10-mT system of Seton et al. (18) signals are coupled to a SQUID via a superconducting tuned circuit, while Clarke and coworkers (22, 25, 26) developed a system at 132 {micro}T with an untuned input circuit coupled to a SQUID. In a quite different approach, atomic magnetometers have been used recently to detect the magnetization (27) and NMR signal (28) of hyperpolarized gases. This technique could potentially be used for low-field MRI in the future. The goal of this review is to summarize the current state-of-the-art of MRI in microtesla fields detected with SQUIDs. The principles of SQUIDs and NMR are briefly reviewed. We show that very narrow NMR linewidths can be achieved in low magnetic fields that are quite inhomogeneous, with illustrative examples from spectroscopy. After describing our ultralow-field MRI system, we present a variety of images. We demonstrate that in microtesla fields the longitudinal relaxation T{sub 1} is much more material dependent than is the case in high fields; this results in a substantial improvement in 'T{sub 1}-weighted contrast imaging'. After outlining the first attempts to combine microtesla NMR with magnetoencephalography (MEG) (29), we conclude with a discussion of future directions.

  10. High-T(sub c) squid application in medicine and geophysics

    Science.gov (United States)

    Polushkin, V. N.; Uchaikin, S. V.; Vasiliev, B. V.

    1990-01-01

    In the Laboratory a high-T(sub c) one-hole squid was built from Y1Ba2Cu3O(7-x) ceramics obtained by a standard procedure of solid state reaction. The ceramics with critical current density J(sub c) is greater than 100 A/sq cm was selected. In the middle of 10 x 10 x 2 mm ceramics pellet a 0.8 mm hole was drilled in which superconducting loop of the squid was located. Between the hole and the edge of the pellet a cut was mechanically filed out with a bridge inside it connecting the superconducting ring. A scheme of the magnetometer is presented. The resonant frequency shift of the tank circuit, the connection of the squid with this circuit, and the squid inductance are evaluated. One of the most interesting fields of the squid-based magnetometer application is biomagnetism, particularly, the human heart magnetocardiogram measuring. The low-temperature squids were used in this area and many interesting and important scientific results have been obtained. The observations have shown that the main noise contribution was not due to the squid but to the Earth's magnetic field variations, industrial inductions, and mainly to the vibrations caused by liquid nitrogen boiling and by vibrations of the box. Further attempts are needed to reduce the magnetic noise inductions. Nevertheless, the estimations promise the maximum signal/noise relation of the high-T(sub c) squid-magnetocardiometer to be not less than 10:1 in a bandwidth of 60 Hz. Apparently, such resolution would be enough not only for steady cardiogram reading but even for thin structure investigation at average technique application.

  11. Foraging ecology and movement patterns of jumbo squid (Dosidicus gigas) in the California Current System

    Science.gov (United States)

    Field, John C.; Elliger, Carl; Baltz, Ken; Gillespie, Graham E.; Gilly, William F.; Ruiz-Cooley, R. I.; Pearse, Devon; Stewart, Julia S.; Matsubu, William; Walker, William A.

    2013-10-01

    From 2002 to 2010, the jumbo squid (Dosidicus gigas) has been regularly encountered in large numbers throughout the California Current System (CCS). This species, usually found in subtropical waters, could affect coastal pelagic ecosystems and fisheries as both predator and prey. Neither the abundance of jumbo squid nor the optimal ocean conditions in which they flourish are well known. To understand better the potential impacts of this species on both commercial fisheries and on food-web structure we collected nearly 900 specimens from waters of the CCS, covering over 20° of latitude, over a range of depths and seasons. We used demographic information (size, sex, and maturity state) and analyzed stomach contents using morphological and molecular methods to best understand the foraging ecology of this species in different habitats of the CCS. Squid were found to consume a broad array of prey. Prey in offshore waters generally reflected the forage base reported in previous studies (mainly mesopelagic fishes and squids), whereas in more coastal waters (shelf, shelf break and slope habitats) squid foraged on a much broader mix that included substantial numbers of coastal pelagic fishes (Pacific herring and northern anchovy, as well as osmerids and salmonids in northern waters) and groundfish (Pacific hake, several species of rockfish and flatfish). We propose a seasonal movement pattern, based on size and maturity distributions along with qualitative patterns of presence or absence, and discuss the relevance of both the movement and distribution of jumbo squid over space and time. We find that jumbo squid are a generalist predator, which feeds primarily on small, pelagic or mesopelagic micronekton but also on larger fishes when they are available. We also conclude that interactions with and potential impacts on ecosystems likely vary over space and time, in response to both seasonal movement patterns and highly variable year-to-year abundance of the squid themselves.

  12. Full noise characterization of a low-noise two-stage SQUID amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Falferi, P [Istituto di Fotonica e Nanotecnologie, CNR-Fondazione Bruno Kessler, 38100 Povo, Trento (Italy); Mezzena, R [INFN, Gruppo Collegato di Trento, Sezione di Padova, 38100 Povo, Trento (Italy); Vinante, A [INFN, Sezione di Padova, 35131 Padova (Italy)], E-mail: falferi@science.unitn.it

    2009-07-15

    From measurements performed on a low-noise two-stage SQUID amplifier coupled to a high- Q electrical resonator we give a complete noise characterization of the SQUID amplifier around the resonator frequency of 11 kHz in terms of additive, back action and cross-correlation noise spectral densities. The minimum noise temperature evaluated at 135 mK is 10 {mu}K and corresponds to an energy resolution of 18{Dirac_h}.

  13. Gradiometer Using Middle Loops as Sensing Elements in a Low-Field SQUID MRI System

    Science.gov (United States)

    Penanen, Konstantin; Hahn, Inseob; Ho Eom, Byeong

    2009-01-01

    A new gradiometer scheme uses middle loops as sensing elements in lowfield superconducting quantum interference device (SQUID) magnetic resonance imaging (MRI). This design of a second order gradiometer increases its sensitivity and makes it more uniform, compared to the conventional side loop sensing scheme with a comparable matching SQUID. The space between the two middle loops becomes the imaging volume with the enclosing cryostat built accordingly.

  14. High-temperature single-layer SQUID gradiometers with long baseline and parasitic effective area compensation

    Energy Technology Data Exchange (ETDEWEB)

    Pegrum, C.M.; Eulenburg, A.; Romans, E.J.; Carr, C.; Millar, A.J.; Donaldson, G.B. [Department of Physics and Applied Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    1999-11-01

    First-order HTS SQUID gradiometers were fabricated on 30x10 mm{sup 2} bicrystal substrates. These devices have a baseline of 13 mm, intrinsic balance levels of {approx}1/700 and a typical gradient sensitivity at 1 kHz of 79 fT cm{sup -1}Hz{sup -1/2}. A two-SQUID coupling scheme is discussed that further enhances the device's ability to reject uniform fields. (author)

  15. Biomolecular Mechanism, Cloning, Sequencing and Analysis of Adaptive Reflection cDNAs and Proteins from Squid

    Science.gov (United States)

    2010-05-03

    Mechanism, Adaptive Reflectance, Adaptive Optics, Reflectin, Bragg Reflectors, cDNA, Protien, Squid, Cephalopod, Octopus Daniel E. Morse University of...Tunable Biophotonics: Camouflage and Communication in Squid Inspire New Approaches to Tunable Optical Materials" MCDB Seminar, UCSB 10/09 Invited...Adaptive Camouflage ”, Alison Sweeney, Daniel DeMartini, Michi Izumi, Amanda Holt, and Daniel E. Morse, presented by Alison Sweeney Reliance 21 Materials

  16. A HTS dc SQUID-NMR: fabrication of the SQUID and application to low-field NMR for fruit quality detection

    Science.gov (United States)

    Isingizwe Nturambirwe, J. Frédéric; Perold, Willem J.; Opara, Linus U.

    2014-06-01

    Superconducting Quantum Interference Devices (SQUIDs) have made the detection of low-field (LF) and ultra-low field nuclear magnetic resonance (ULF-NMR) a reality. The latter has been proven to be a potential tool for non-destructive quality testing of horticultural products, amongst many other applications. High-Temperature Superconductor (HTS) dc SQUIDS are likely to allow for the development of not only low-cost NMR systems but also prototypes that are mobile and easily maintainable. A HTS dc SQUID was manufactured on an YBCO thin film, using a novel laser based lithography method. The lithography was implemented by a new laser system developed in-house, as a model of low-cost lithography systems. The junctions of the dc SQUID were tested and displayed normal I-V characteristics in the acceptable range for the application. In order to determine the viability of low-field NMR for non-destructive quality measurement of horticultural products, a commercial HTS dc SQUID-NMR system was used to measure quality parameters of banana during ripening. The trend of color change and sugar increase of the banana during ripening were the most highly correlated attributes to the SQUID-NMR measured parameter, average T1 (spin-lattice relaxation time). Further studies were done, that involved processing of the NMR signal into relaxation time resolved spectra. A spectral signature of banana was obtained, where each peak is a T1 value corresponding to a proton pool, and is reported here. These results will potentially lead to deeper understanding of the quality of the samples under study.

  17. Material properties of Pacific hake, Humboldt squid, and two species of myctophids in the California Current.

    Science.gov (United States)

    Becker, Kaylyn N; Warren, Joseph D

    2015-05-01

    Material properties of the flesh from three fish species (Merluccius productus, Symbolophorus californiensis, and Diaphus theta), and several body parts of the Humboldt squid (Dosidicus gigas) collected from the California Current ecosystem were measured. The density contrast relative to seawater varied within and among taxa for fish flesh (0.9919-1.036), squid soft body parts (mantle, arms, tentacle, braincase, eyes; 1.009-1.057), and squid hard body parts (beak and pen; 1.085-1.459). Effects of animal length and environmental conditions on nekton density contrast were investigated. The sound speed contrast relative to seawater varied within and among taxa for fish flesh (0.986-1.027) and Humboldt squid mantle and braincase (0.937-1.028). Material properties in this study are similar to values from previous studies on species with similar life histories. In general, the sound speed and density of soft body parts of fish and squid were 1%-3% and 1%-6%, respectively, greater than the surrounding seawater. Hard parts of the squid were significantly more dense (6%-46%) than seawater. The material properties reported here can be used to improve target strength estimates from acoustic scattering models, which could increase the accuracy of biomass estimates from acoustic surveys for these nekton.

  18. Identification of four squid species by quantitative real-time polymerase chain reaction.

    Science.gov (United States)

    Ye, Jian; Feng, Junli; Liu, Shasha; Zhang, Yanping; Jiang, Xiaona; Dai, Zhiyuan

    2016-02-01

    Squids are distributed worldwide, including many species of commercial importance, and they are often made into varieties of flavor foods. The rapid identification methods for squid species especially their processed products, however, have not been well developed. In this study, quantitative real-time PCR (qPCR) systems based on specific primers and TaqMan probes have been established for rapid and accurate identification of four common squid species (Ommastrephes bartramii, Dosidicus gigas, Illex argentinus, Todarodes pacificus) in Chinese domestic market. After analyzing mitochondrial genes reported in GenBank, the mitochondrial cytochrome b (Cytb) gene was selected for O. bartramii detection, cytochrome c oxidase subunit I (COI) gene for D. gigas and T. Pacificus detection, ATPase subunit 6 (ATPase 6) gene for I. Argentinus detection, and 12S ribosomal RNA (12S rDNA) gene for designing Ommastrephidae-specific primers and probe. As a result, all the TaqMan systems are of good performance, and efficiency of each reaction was calculated by making standard curves. This method could detect target species either in single or mixed squid specimen, and it was applied to identify 12 squid processed products successfully. Thus, it would play an important role in fulfilling labeling regulations and squid fishery control.

  19. Development of 2D Bi-SQUID Arrays with High Linearity

    CERN Document Server

    Berggren, S; Longhini, P; Palacios, A; Mukhanov, O A; de Escobar, A Leese; Taylor, B J; de Andrade, M C; Nisenoff, M; Fagaly, R L; Wong, T; Cho, E; Wong, E; In, V

    2013-01-01

    We develop a two-dimensional (2D) Superconducting Quantum Interference Filter (SQIF) array based on recently introduced high-linearity tri-junction bi-SQUIDs. Our bi-SQUID SQIF array design is based on a tight integration of individual bi- SQUID cells sharing inductances with adjacent cells. We provide extensive computer simulations, analysis and experimental measurements, in which we explore the phase dynamics and linearity of the array voltage response. The non-uniformity in inductances of the bi-SQUIDs produces a pronounced zero-field single antipeak in the voltage response. The anti-peak linearity and size can be optimized by varying the critical current of the additional junction of each bi-SQUID. The layout implementation of the tight 2D array integration leads to a distinct geometrical diamond shape formed by the merged dual bi-SQUID cells. Different size 2D arrays are fabricated using standard HYPRES niobium 4.5 kA/cm2 fabrication process. The measured linearity, power gain, and noise properties will ...

  20. Development of 1.3GHz high-Tc rf SQUID

    Institute of Scientific and Technical Information of China (English)

    Liu Xin-Yuan; Xie Fei-Xiang; Meng Shu-Chao; Dai Yuan-Dong; Li Zhuang-Zhi; Ma Ping; Yang Tao; Nie Rui-Juan; Wang Fu-Ren

    2004-01-01

    @@ A new high-Tc (HTc) rf SQUID working at around 1.3GHz has been developed to avoid electromagnetic interference such as growing mobile communication jamming. This new system works in a frequency range from 1.23 to 1.42GHz (centred at 1.3GHz), which is not occupied by commercial communication. The sensor used in the 1.3GHz rf SQUID is made of a HTc coplanar superconducting resonator and a large-area HTc superconducting film concentrator. We have achieved in the 1.3GHz HTc rf SQUID system a minimal flux noise of 2.5×10-5φ0/√Hz and a magnetic field sensitivity of 38fT/√Hz in white noise range, respectively. The effective area of the concentrator fabricated on a 15×15mm2 substrate is 1.35mm2. It is shown that the 1.3GHz rf SQUID system has a high field sensitivity. Design and implementation of 1.3GHz HTc rf SQUID offers a promising direction of rf SQUID development for higher working frequency ranges.

  1. Using a summary measure for multiple quality indicators in primary care: the Summary QUality InDex (SQUID

    Directory of Open Access Journals (Sweden)

    Nemeth Lynne S

    2007-04-01

    Full Text Available Abstract Background Assessing the quality of primary care is becoming a priority in national healthcare agendas. Audit and feedback on healthcare quality performance indicators can help improve the quality of care provided. In some instances, fewer numbers of more comprehensive indicators may be preferable. This paper describes the use of the Summary Quality Index (SQUID in tracking quality of care among patients and primary care practices that use an electronic medical record (EMR. All practices are part of the Practice Partner Research Network, representing over 100 ambulatory care practices throughout the United States. Methods The SQUID is comprised of 36 process and outcome measures, all of which are obtained from the EMR. This paper describes algorithms for the SQUID calculations, various statistical properties, and use of the SQUID within the context of a multi-practice quality improvement (QI project. Results At any given time point, the patient-level SQUID reflects the proportion of recommended care received, while the practice-level SQUID reflects the average proportion of recommended care received by that practice's patients. Using quarterly reports, practice- and patient-level SQUIDs are provided routinely to practices within the network. The SQUID is responsive, exhibiting highly significant (p Conclusion The SQUID algorithm is feasible and straightforward, and provides a useful QI tool. Its statistical properties and clear interpretation make it appealing to providers, health plans, and researchers.

  2. Potential enhanced ability of giant squid to detect sperm whales is an exaptation tied to their large body size.

    Science.gov (United States)

    Schmitz, Lars; Motani, Ryosuke; Oufiero, Christopher E; Martin, Christopher H; McGee, Matthew D; Wainwright, Peter C

    2013-01-01

    It has been hypothesized that sperm whale predation is the driver of eye size evolution in giant squid. Given that the eyes of giant squid have the size expected for a squid this big, it is likely that any enhanced ability of giant squid to detect whales is an exaptation tied to their body size. Future studies should target the mechanism behind the evolution of large body size, not eye size. Reconstructions of the evolutionary history of selective regime, eye size, optical performance, and body size will improve the understanding of the evolution of large eyes in large ocean animals.

  3. Optical parameters of the tunable Bragg reflectors in squid.

    Science.gov (United States)

    Ghoshal, Amitabh; Demartini, Daniel G; Eck, Elizabeth; Morse, Daniel E

    2013-08-06

    Cephalopods (e.g. octopus, squid and cuttlefish) dynamically tune the colour and brightness of their skin for camouflage and communication using specialized skin cells called iridocytes. We use high-resolution microspectrophotometry to investigate individual tunable Bragg structures (consisting of alternating reflectin protein-containing, high-refractive index lamellae and low-refractive index inter-lamellar spaces) in live and chemically fixed iridocytes of the California market squid, Doryteuthis opalescens. This subcellular, single-stack microspectrophotometry allows for spectral normalization, permitting use of a transfer-matrix model of Bragg reflectance to calculate all the parameters of the Bragg stack-the refractive indices, dimensions and numbers of the lamellae and inter-lamellar spaces. Results of the fitting analyses show that eight or nine pairs of low- and high-index layers typically contribute to the observed reflectivity in live cells, whereas six or seven pairs of low- and high-index layers typically contribute to the reflectivity in chemically fixed cells. The reflectin-containing, high-index lamellae of live cells have a refractive index proportional to the peak reflectivity, with an average of 1.405 ± 0.012 and a maximum around 1.44, while the reflectin-containing lamellae in fixed tissue have a refractive index of 1.413 ± 0.015 suggesting a slight increase of refractive index in the process of fixation. As expected, incremental changes in refractive index contribute to the greatest incremental changes in reflectivity for those Bragg stacks with the most layers. The excursions in dimensions required to tune the measured reflected wavelength from 675 (red) to 425 nm (blue) are a decrease from ca 150 to 80 nm for the high-index lamellae and from ca 120 to 50 nm for the low-index inter-lamellar spaces. Fixation-induced dimensional changes also are quantified, leading us to suggest that further microspectrophotometric analyses of this iridocyte

  4. SQUID biosusceptometry in the measurement of hepatic iron

    Energy Technology Data Exchange (ETDEWEB)

    Sheth, Sujit [Department of Pediatrics, Columbia University College of Physicians and Surgeons, Harkness Pavilion, Room HP570, 180 Fort Washington Avenue, NY 10032, New York (United States)

    2003-06-01

    Individuals with primary or secondary abnormalities of iron metabolism, such as hereditary hemochromatosis and transfusional iron loading, may develop potentially lethal systemic iron overload. Over time, this excess iron is progressively deposited in the liver, heart, pancreas, and other organs, resulting in cirrhosis, heart disease, diabetes and other disorders. Unless treated, death usually results from cardiac failure. The amount of iron in the liver is the best indicator of the amount of iron in the whole body. At present, the only sure way to measure the amount of iron in the liver is to remove a sample of the liver by biopsy. Iron stored in the liver can be magnetized to a small degree when placed in a magnetic field. The amount of magnetization is measured by our instrument, called a superconducting quantum interference device (SQUID) susceptometer. In patients with iron overload, our previous studies have shown that magnetic measurements of liver iron in patients with iron overload are quantitatively equivalent to biochemical determinations on tissue obtained by biopsy. The safety, ease, rapidity, and comfort of magnetic measurements make frequent, serial studies technically feasible and practically acceptable to patients. (orig.)

  5. Thermal instabilities in micro-SQUIDs with long leads

    Science.gov (United States)

    Kumar, Nikhil; Fournier, T.; Courtois, H.; Winkelmann, C. B.; Gupta, Anjan K.

    2015-03-01

    We report on Nb film based micron-size superconducting quantum interference devices (μ-SQUIDs) with long leads and with constrictions as weak-links (WLs). The current-voltage characteristics (IVCs) of these devices are hysteretic at low temperatures (T) with two re-trapping currents, Ir1 and Ir2, arising from thermal instabilities, and a critical-current (Ic) . We see oscillations with magnetic flux in Ic, but not in Ir1 and Ir2, in both the hysteretic and non-hysteretic regimes. We describe a one dimensional model for thermal instability in long-leads to understand re-trapping currents and its T-dependence. The critical-current shows a marked change in behaviour at the crossover temperature when it meets the lower re-trapping current and above this temperature the critical current subsists due to proximity superconductivity. The thermal stability with respect to phase-slips evolves with temperature and only above the crossover temperature the weak-link can cope with the heat generated by phase-slips giving a non-hysteretic behaviour. Keeping other device dimensions same the WLs' dimensions give a control on the hysteresis-free T-range. NK acknowledges the financial support from CSIR, India as well as CNRS-Institute Néel, Grenoble, France.

  6. Sodium movements in perfused squid giant axons. Passive fluxes.

    Science.gov (United States)

    Rojas, E; Canessa-Fischer, M

    1968-08-01

    Sodium movements in internally perfused giant axons from the squid Dosidicus gigas were studied with varying internal sodium concentrations and with fluoride as the internal anion. It was found that as the internal concentration of sodium was increased from 2 to 200 mM the resting sodium efflux increased from 0.09 to 34.0 pmoles/cm(2)sec and the average resting sodium influx increased from 42.9 to 64.5 pmoles/cm(2)sec but this last change was not statistically significant. When perfusing with a mixture of 500 mM K glutamate and 100 mM Na glutamate the resting efflux was 10 +/- 3 pmoles/cm(2)sec and 41 +/- 10 pmoles/cm(2)sec for sodium influx. Increasing the internal sodium concentration also increased both the extra influx and the extra efflux of sodium due to impulse propagation. At any given internal sodium concentration the net extra influx was about 5 pmoles/cm(2)impulse. This finding supports the notion that the inward current generated in a propagated action potential can be completely accounted for by movements of sodium.

  7. Jumbo squid beaks: inspiration for design of robust organic composites.

    Science.gov (United States)

    Miserez, Ali; Li, Youli; Waite, J Herbert; Zok, Frank

    2007-01-01

    The hard tissues found in some invertebrate marine organisms represent intriguing paradigms for robust, lightweight materials. The present study focuses on one such tissue: that comprising the beak of the jumbo squid (Dosidicus gigas). Its main constituents are chitin fibers (15-20wt.%) and histidine- and glycine-rich proteins (40-45%). Notably absent are mineral phases, metals and halogens. Despite being fully organic, beak hardness and stiffness are at least twice those of the most competitive synthetic organic materials (notably engineering polymers) and comparable to those of Glycera and Nereis jaws. Furthermore, the combination of hardness and stiffness makes the beaks more resistant to plastic deformation when in contact with blunt abrasives than virtually all metals and polymers. The 3,4-dihydroxy-l-phenylalanine and abundant histidine content in the beak proteins as well as the pigmented hydrolysis-resistant residue are suggestive of aromatic cross-linking. A high cross-linking density between the proteins and chitin may be the single most important determinant of hardness and stiffness in the beak. Beak microstructure is characterized by a lamellar arrangement of the constituents, with a weak interface that promotes crack deflection and endows the structure with high fracture toughness. The susceptibility of this microstructure to cracking along these interfaces from contact stresses at the external surface is mitigated by the presence of a protective coating.

  8. Squid Pen Chitin Chitooligomers as Food Colorants Absorbers

    Directory of Open Access Journals (Sweden)

    Tzu-Wen Liang

    2015-01-01

    Full Text Available One of the most promising applications of chitosanase is the conversion of chitinous biowaste into bioactive chitooligomers (COS. TKU033 chitosanase was induced from squid pen powder (SPP-containing Bacillus cereus TKU033 medium and purified by ammonium sulfate precipitation and column chromatography. The enzyme was relatively more thermostable in the presence of the substrate and had an activity of 93% at 50 °C in a pH 5 buffer solution for 60 min. Furthermore, the enzyme used for the COS preparation was also studied. The enzyme products revealed various mixtures of COS that with different degrees of polymerization (DP, ranging from three to nine. In the culture medium, the fermented SPP was recovered, and it displayed a better adsorption rate (up to 96% for the disperse dyes than the water-soluble food colorants, Allura Red AC (R40 and Tartrazne (Y4. Fourier transform-infrared spectroscopic (FT-IR analysis proved that the adsorption of the dyes onto fermented SPP was a physical adsorption. Results also showed that fermented SPP was a favorable adsorber and could be employed as low-cost alternative for dye removal in wastewater treatment.

  9. Development of Contaminant Detection System using HTS SQUIDs

    Energy Technology Data Exchange (ETDEWEB)

    Ohtani, T.; Tanaka, S.; Narita, Y.; Ariyoshi, S. [National University Corporation, Toyohashi University of Technology, Toyohash (Japan); Suzuki, S. [Advance Food Technology Co., Ltd., Toyohashi (Japan)

    2015-12-15

    In terms of food safety, mixture of contaminants in food is a serious problem for not only consumers but also manufacturers. In general, the target size of the metallic contaminant to be removed is 0.5 mm. However, it is a difficult task for manufacturers to achieve this target, because of lower system sensitivity. Therefore, we developed a food contaminant detection system based on high-Tc RF superconducting quantum interference devices (SQUIDs), which are highly sensitive magnetic sensors. This study aims to improve the signal to noise ratio (SNR) of the system and detect a 0.5 mm diameter steel ball. Using a real time digital signal processing technique along with analog band-pass filters, we improved the SNR of the system. Owing to the improved SNR, a steel ball with a diameter as small as 0.3 mm, with stand-off distance of 117 mm was successfully detected. These results suggest that the proposed system is a promising candidate for the detection of metallic contaminants in food products.

  10. A tunable rf SQUID manipulated as flux and phase qubits

    Energy Technology Data Exchange (ETDEWEB)

    Poletto, S; Lisenfeld, J; Lukashenko, A; Ustinov, A V [Physikalisches Institut, Universitaet Karlsruhe (Thailand), D-76131 Karlsruhe (Germany); Chiarello, F; Castellano, M G [Istituto di Fotonica e Nanotecnologie, CNR, 00156 Roma (Italy); Carelli, P [Dipartimento di Ingegneria Elettrica, Universita dell' Aquila, 67040 Monteluco di Roio (Italy)], E-mail: ustinov@physik.uni-karlsruhe.de

    2009-12-15

    We report on two different manipulation procedures of a tunable rf superconducting quantum interference device (SQUID). First, we operate this system as a flux qubit, where the coherent evolution between the two flux states is induced by a rapid change of the energy potential, turning it from a double well into a single well. The measured coherent Larmor-like oscillation of the retrapping probability in one of the wells has a frequency ranging from 6 to 20 GHz, with a theoretically expected upper limit of 40 GHz. Furthermore, here we also report a manipulation of the same device as a phase qubit. In the phase regime, the manipulation of the energy states is realized by applying a resonant microwave drive. In spite of the conceptual difference between these two manipulation procedures, the measured decay times of Larmor oscillation and microwave-driven Rabi oscillation are rather similar. Due to the higher frequency of the Larmor oscillations, the microwave-free qubit manipulation allows for much faster coherent operations.

  11. Deep-well ultrafast manipulation of a SQUID flux qubit

    Energy Technology Data Exchange (ETDEWEB)

    Castellano, M G; Chiarello, F; Mattioli, F; Torrioli, G [Istituto Fotonica e Nanotecnologie-CNR, Roma (Italy); Carelli, P [Dip. Ingegneria Elettrica e dell' Informazione, Universita dell' Aquila, L' Aquila (Italy); Cosmelli, C, E-mail: mgcastellano@ifn.cnr.i [Dip. Fisica, Sapienza Universita di Roma (Italy)

    2010-04-15

    Superconducting devices based on the Josephson effect are effectively used for the implementation of qubits and quantum gates. The manipulation of superconducting qubits is generally performed by using microwave pulses with frequencies from 5 to 15 GHz, obtaining a typical operating frequency from 100 MHz to 1 GHz. A manipulation based on simple pulses in the absence of microwaves is also possible. In our system, a magnetic flux pulse modifies the potential of a double SQUID qubit from a symmetric double well to a single deep-well condition. By using this scheme with a Nb/AlO{sub x}/Nb system, we obtained coherent oscillations with sub-nanosecond period (tunable from 50 to 200 ps), very fast with respect to other manipulating procedures, and with a coherence time up to 10 ns, of the order of that obtained with similar devices and technologies but using microwave manipulation. We introduce ultrafast manipulation, presenting experimental results, new issues related to this approach (such as the use of a compensation procedure for canceling the effect of 'slow' fluctuations) and open perspectives, such as the possible use of RSFQ logic for qubit control.

  12. An interchangeable scanning Hall probe/scanning SQUID microscope.

    Science.gov (United States)

    Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin; Chen, Tse-Jun; Wang, M J; Ling, D C; Chi, C C; Chen, Jeng-Chung

    2014-08-01

    We have constructed a scanning probe microscope for magnetic imaging, which can function as a scanning Hall probe microscope (SHPM) and as a scanning SQUID microscope (SSM). The scanning scheme, applicable to SHPM and SSM, consists of a mechanical positioning (sub) micron-XY stage and a flexible direct contact to the sample without a feedback control system for the Z-axis. With the interchangeable capability of operating two distinct scanning modes, our microscope can incorporate the advantageous functionalities of the SHPM and SSM with large scan range up to millimeter, high spatial resolution (⩽4 μm), and high field sensitivity in a wide range of temperature (4.2 K-300 K) and magnetic field (10(-7) T-1 T). To demonstrate the capabilities of the system, we present magnetic images scanned with SHPM and SSM, including a RbFeB magnet and a nickel grid pattern at room temperature, surface magnetic domain structures of a La(2/3)Ca(1/3)MnO3 thin film at 77 K, and superconducting vortices in a striped niobium film at 4.2 K.

  13. Squid pen chitin chitooligomers as food colorants absorbers.

    Science.gov (United States)

    Liang, Tzu-Wen; Huang, Chih-Ting; Dzung, Nguyen Anh; Wang, San-Lang

    2015-01-20

    One of the most promising applications of chitosanase is the conversion of chitinous biowaste into bioactive chitooligomers (COS). TKU033 chitosanase was induced from squid pen powder (SPP)-containing Bacillus cereus TKU033 medium and purified by ammonium sulfate precipitation and column chromatography. The enzyme was relatively more thermostable in the presence of the substrate and had an activity of 93% at 50 °C in a pH 5 buffer solution for 60 min. Furthermore, the enzyme used for the COS preparation was also studied. The enzyme products revealed various mixtures of COS that with different degrees of polymerization (DP), ranging from three to nine. In the culture medium, the fermented SPP was recovered, and it displayed a better adsorption rate (up to 96%) for the disperse dyes than the water-soluble food colorants, Allura Red AC (R40) and Tartrazne (Y4). Fourier transform-infrared spectroscopic (FT-IR) analysis proved that the adsorption of the dyes onto fermented SPP was a physical adsorption. Results also showed that fermented SPP was a favorable adsorber and could be employed as low-cost alternative for dye removal in wastewater treatment.

  14. Identifying Pelagic Habitat Hotspots of Neon Flying Squid in the Temperate Waters of the Central North Pacific.

    Directory of Open Access Journals (Sweden)

    Irene D Alabia

    Full Text Available We identified the pelagic habitat hotspots of the neon flying squid (Ommastrephes bartramii in the central North Pacific from May to July and characterized the spatial patterns of squid aggregations in relation to oceanographic features such as mesoscale oceanic eddies and the Transition Zone Chlorophyll-a Front (TZCF. The data used for the habitat model construction and analyses were squid fishery information, remotely-sensed and numerical model-derived environmental data from May to July 1999-2010. Squid habitat hotspots were deduced from the monthly Maximum Entropy (MaxEnt models and were identified as regions of persistent high suitable habitat across the 12-year period. The distribution of predicted squid habitat hotspots in central North Pacific revealed interesting spatial and temporal patterns likely linked with the presence and dynamics of oceanographic features in squid's putative foraging grounds from late spring to summer. From May to June, the inferred patches of squid habitat hotspots developed within the Kuroshio-Oyashio transition zone (KOTZ; 37-40°N and further expanded north towards the subarctic frontal zone (SAFZ; 40-44°N in July. The squid habitat hotspots within the KOTZ and areas west of the dateline (160°W-180° were likely influenced and associated with the highly dynamic and transient oceanic eddies and could possibly account for lower squid suitable habitat persistence obtained from these regions. However, predicted squid habitat hotspots located in regions east of the dateline (180°-160°W from June to July, showed predominantly higher squid habitat persistence presumably due to their proximity to the mean position of the seasonally-shifting TZCF and consequent utilization of the highly productive waters of the SAFZ.

  15. Closed-cycle cryocooled SQUID system with superconductive shield for biomagnetism

    Science.gov (United States)

    Yu, Kwon Kyu; Lee, Yong Ho; Lee, Seong Joo; Shim, Jeong Hyun; Hwang, Seong min; Kim, Jin Mok; Kwon, Hyuckchan; Kim, Kiwoong

    2014-10-01

    We developed a cryocooled SQUID system with which human magnetocardiogram (MCG) and possibly magnetoenceparogram (MEG) can be measured. To reduce cyclic magnetic noises originating from the regenerator of the cold heads of the cryocooler, a superconductive shield (99.5% Pb) was used to protect the SQUID sensors, and a ferromagnetic shield (78% Ni alloy) was used to screen the cold head. In addition, the SQUID sensors’ chamber was placed at a distance of 1.8 m from the cold head chamber to install the cold-head chamber outside the magnetically shielded room (MSR) for future development. The loss in cooling power due to the increased distance was compensated by increasing the number of thermal rods, and thus the SQUID sensor and superconductive shield could be refrigerated to 4.8 K and 5 K, respectively. The superconductive shield successfully rejected thermal noise emitted from metallic blocks used to improve thermal conduction. The noise of the SQUID system was 3 fT/Hz1/2, and the cyclic magnetic noise could be reduced to 1.7 pT. We could obtain a clear MCG signal while the entire cryogenics was in operation without any special digital processing.

  16. Partial characterization of an effluent produced by cooking of Jumbo squid (Dosidicus gigas) mantle muscle.

    Science.gov (United States)

    Rosas-Romero, Zaidy G; Ramirez-Suarez, Juan C; Pacheco-Aguilar, Ramón; Lugo-Sánchez, Maria E; Carvallo-Ruiz, Gisela; García-Sánchez, Guillermina

    2010-01-01

    Jumbo squid (Dosidicus gigas) mantle muscle was cooked simulating industrial procedures (95 degrees C x 25 min, 1.2:5 muscle:water ratio). The effluent produced was analyzed for chemical and biochemical oxygen demands (COD and BOD(5), respectively), proximate analysis, flavor-related compounds (free amino acids, nucleotides and carbohydrates) and SDS-PAGE. The COD and BOD(5) exhibited variation among samplings (N=3) (27.4-118.5 g O(2)/L for COD and 11.3-26.7 g O(2)/L for BOD(5)). The effluent consisted of 1% total solids, 75% of which represented crude protein. Sixty percent of the total free amino acid content, which imparts flavor in squid species, corresponded to glutamic acid, serine, glycine, arginine, alanine, leucine and lysine. The nucleotide concentration followed this order, Hx>ADP>AMP>ATP>IMP>HxR. The variation observed in the present work was probably due to physiological maturity differences among the squid specimens (i.e., juvenile versus mature). Solids present in squid cooking effluent could be recovered and potentially used as flavor ingredients in squid-analog production by the food industry.

  17. Vestigial phragmocone in the gladius points to a deepwater origin of squid (Mollusca: Cephalopoda)

    Science.gov (United States)

    Arkhipkin, Alexander I.; Bizikov, Vyacheslav A.; Fuchs, Dirk

    2012-03-01

    The microstructure of the gladius cone was investigated in six species of nektonic squid: shallow-water Loligo gahi (Loliginidae), pelagic eurybathic Illex argentinus, Todarodes pacificus, Dosidicus gigas (Ommastrephidae), and deepwater Onykia ingens (Onychoteuthidae) and Gonatus antarcticus (Gonatidae) using state-of-the-art microscopy. Apart from L. gahi, all other species had septa-like layers in the gladius cone, which for the first time were investigated in detail and compared with those in extinct Cretaceous belemnites Hibolithes sp. and Pachyteuthis sp., and spirulid Cyrtobelus sp. It was found that the organic layers of the gladius cone in recent squid can be homologized with the organic components of the shell in fossil phragmocone-bearing coleoids. The septa-like layers in modern gladius cones therefore represent a vestigial phragmocone composed of organic septal rudiments of the ancestral phragmocone that has lost the siphuncle and gas-filled chambers. The well-developed rostrum in onychoteuthids and small rostrum of the gladius in ommastrephids and gonatids can be seen as homologous with the belemnoid rostrum, which may indicate a close phylogenetic relationship between belemnites and at least some squid. Possible evolutionary pathways of the reduction of the functional phragmocone in squid ancestors are discussed. Several features such as the loss of shell calcification, deep water speciation, and the structure of the equilibrium organ point to a deep-water origin of squids.

  18. Behavioral ecology of jumbo squid (Dosidicus gigas) in relation to oxygen minimum zones

    Science.gov (United States)

    Stewart, Julia S.; Field, John C.; Markaida, Unai; Gilly, William F.

    2013-10-01

    Habitat utilization, behavior and food habits of the jumbo or Humboldt squid, Dosidicus gigas, were compared between an area recently inhabited in the northern California Current System (CCS) and a historically established area of residence in the Gulf of California (GOC). Low dissolved oxygen concentrations at midwater depths define the oxygen minimum zone (OMZ), an important environmental feature in both areas. We analyzed vertical diving behavior and diet of D. gigas and hydrographic properties of the water column to ascertain the extent to which squid utilized the OMZ in the two areas. The upper boundary of the OMZ has been shoaling in recent decades in the CCS, and this phenomenon has been proposed to vertically compress the pelagic environment inhabited by aerobic predators. A shoaling OMZ will also bring mesopelagic communities into a depth range with more illumination during daytime, making these organisms more vulnerable to predation by visual predators (i.e. jumbo squid). Because the OMZ in the GOC is considerably shallower than in the CCS, our study provides insight into the behavioral plasticity of jumbo squid and how they may respond to a shoaling OMZ in the CCS. We propose that shoaling OMZs are likely to be favorable to jumbo squid and could be a key indirect factor behind the recent range expansion of this highly migratory predator.

  19. Step edge Josephson junctions and high temperature superconducting quantum interference device (SQUID) gradiometers

    CERN Document Server

    Millar, A J

    2002-01-01

    This thesis is concerned with the development of Superconducting Quantum Interference Device (SQUID) gradiometers based on the high temperature superconductor YBa sub 2 Cu sub 3 O sub 7 sub - subdelta (YBCO). A step-edge Josephson junction fabrication process was developed to produce sufficiently steep (>60 deg) step-edges such that junctions exhibited RSJ-like current-voltage characteristics. The mean I sub C R sub N product of a sample of twenty step-edge junctions was 130 mu V. Step-edge dc SQUIDs with inductances between 67pH and 114pH were fabricated. Generally the SQUIDs had an intrinsic white flux noise in the 10-30 mu PHI sub 0 /sq root Hz range, with the best device, a 70pH SQUID, exhibiting a white flux noise of 5 mu PHI sub 0 /sq root Hz. Different first-order SQUID gradiometer designs were fabricated from single layers of YBCO. Two single-layer gradiometer (SLG) designs were fabricated on 10x10mm sup 2 substrates. The best balance and lowest gradient sensitivity measured for these devices were 1/3...

  20. Microbial Experimental Evolution as a Novel Research Approach in the Vibrionaceae and Squid-Vibrio Symbiosis

    Directory of Open Access Journals (Sweden)

    William eSoto

    2014-12-01

    Full Text Available The Vibrionaceae are a genetically and metabolically diverse family living in aquatic habitats with a great propensity toward developing interactions with eukaryotic microbial and multicellular hosts (as either commensals, pathogens, and mutualists. The Vibrionaceae frequently possess a life history cycle where bacteria are attached to a host in one phase and then another where they are free from their host as either part of the bacterioplankton or adhered to a solid substrate such as marine sediment, riverbeds, lakebeds, or floating particulate debris. These two stages in their life history exert quite distinct and separate selection pressures. When bound to solid substrates or to host cells, the Vibrionaceae can also exist as complex biofilms. The association between bioluminescent Vibrio spp. and sepiolid squids (Cephalopoda: Sepiolidae is an experimentally tractable model to study bacteria and animal host interactions, since the symbionts and squid hosts can be maintained in the laboratory independently of one another. The bacteria can be grown in pure culture and the squid hosts raised gnotobiotically with sterile light organs. The partnership between free-living Vibrio symbionts and axenic squid hatchlings emerging from eggs must be renewed every generation of the cephalopod host. Thus, symbiotic bacteria and animal host can each be studied alone and together in union. Despite virtues provided by the Vibrionaceae and sepiolid squid-Vibrio symbiosis, these assets to evolutionary biology have yet to be fully utilized for microbial experimental evolution. Experimental evolution studies already completed are reviewed, along with exploratory topics for future study.

  1. The effect of phosphorylation on arrestin-rhodopsin interaction in the squid visual system.

    Science.gov (United States)

    Robinson, Kelly A; Ou, Wei-Lin; Guan, Xinyu; Sugamori, Kim S; Bandyopadhyay, Abhishek; Ernst, Oliver P; Mitchell, Jane

    2015-12-01

    Invertebrate visual opsins are G protein-coupled receptors coupled to retinoid chromophores that isomerize reversibly between inactive rhodopsin and active metarhodopsin upon absorption of photons of light. The squid visual system has an arrestin protein that binds to metarhodopsin to block signaling to Gq and activation of phospholipase C. Squid rhodopsin kinase (SQRK) can phosphorylate both metarhodopsin and arrestin, a dual role that is unique among the G protein-coupled receptor kinases. The sites and role of arrestin phosphorylation by SQRK were investigated here using recombinant proteins. Arrestin was phosphorylated on serine 392 and serine 397 in the C-terminus. Unphosphorylated arrestin bound to metarhodopsin and phosphorylated metarhodopsin with similar high affinities (Kd 33 and 21 nM respectively), while phosphorylation of arrestin reduced the affinity 3- to 5-fold (Kd 104 nM). Phosphorylation of metarhodopsin slightly increased the dissociation of arrestin observed during a 1 hour incubation. Together these studies suggest a unique role for SQRK in phosphorylating both receptor and arrestin and inhibiting the binding of these two proteins in the squid visual system. Invertebrate visual systems are inactivated by arrestin binding to metarhodopsin that does not require receptor phosphorylation. Here we show that squid rhodopsin kinase phosphorylates arrestin on two serines (S392,S397) in the C-terminus and phosphorylation decreases the affinity of arrestin for squid metarhodopsin. Metarhodopsin phosphorylation has very little effect on arrestin binding but does increase arrestin dissociation.

  2. Multi-elemental concentrations in the tissues of the oceanic squid Todarodes filippovae from Tasmania and the southern Indian Ocean.

    Science.gov (United States)

    Kojadinovic, Jessica; Jackson, Christine H; Cherel, Yves; Jackson, George D; Bustamante, Paco

    2011-07-01

    This study investigates 14 elements (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V and Zn) in the tissues of the oceanic ommastrephid squid Todarodes filippovae from waters surrounding Île Amsterdam (southern Indian Ocean) and Tasmania (Australia). As for other cephalopod species, the digestive gland and branchial hearts showed the highest concentrations of many elements (Ag, Cd, Se, V and Zn, and Cr and Ni, respectively) highlighting their role in bioaccumulation and detoxification processes. With the exception of As and Hg, the muscles showed relatively low trace element concentrations. Squid size was positively correlated to Ag, As, Cd, Hg and Zn concentrations in Tasmanian squid and negatively correlated to all but Hg and Zn concentrations in Île Amsterdam squid. Furthermore, no differences in elemental concentrations were noted between sexes. There were, however, some differences between mated and non-mated females from Tasmania. Comparing elemental concentrations in squid from both islands, higher concentrations of Cd, Co, Cr, Ni, Pb and V in squid sampled in Île Amsterdam reflect different exposure conditions. When considering T. filippovae as a dietary resource for humans it should be noted that, given their Hg content, squids from Île Amsterdam are not recommended for consumption on a regular basis. Moreover, regardless of the squid's origin, digestive glands should be avoided as Cd and Hg concentrations were above the European Union authorized limits in these organs.

  3. 76 FR 3044 - Fisheries of the Exclusive Economic Zone Off Alaska; Sculpins, Sharks, Squid, and Octopus in the...

    Science.gov (United States)

    2011-01-19

    ... Economic Zone Off Alaska; Sculpins, Sharks, Squid, and Octopus in the Gulf of Alaska AGENCY: National... octopus in the Gulf of Alaska (GOA). This action is necessary to prevent exceeding the 2011 total allowable catch (TAC) of sculpins, sharks, squid, and octopus in the GOA. DATES: Effective 1200 hrs,...

  4. The male reproductive strategy of a deep-sea squid : sperm allocation, continuous production, and long-term storage of spermatophores in Histioteuthis miranda

    NARCIS (Netherlands)

    Hoving, Hendrik Jan T.; Lipinski, Marek R.; Dam, Lammertjan

    2010-01-01

    Squid are semelparous organisms. Much of what we know about squid reproduction relates to females, because few studies have addressed males and, although males are similarly challenged by semelparity, it remains virtually unknown what tactics squid have evolved to allocate sperm to spermatophores. T

  5. Inductance measurements in multilevel high Tc step-edge grain boundary SQUIDS

    Science.gov (United States)

    Forrester, M. G.; Davidson, A.; Talvacchio, J.; Gavaler, J. R.; Przybysz, J. X.

    1994-10-01

    Multilevel high Tc SQUIDs, suitable for digital circuit applications, have been fabricated and tested. The devices employ a YBa2Cu3O7-δ (YBCO) ground plane, an epitaxial SrTiO3 insulator, and a YBCO microstrip layer. Junctions are formed by the step-edge grain boundary process, with a ground plane contact for the ``low'' side of each junction, using only isotropic sputtering and milling techniques. Control current is directly injected in a microstrip segment of the SQUID loop, allowing us to measure the microstrip inductance, and thus to infer the magnetic penetration depth of the YBCO. The SQUIDs are operational above 77 K, at which temperature we infer a penetration depth of 350 nm. The temperature dependence of the penetration depth is found to be in reasonable agreement with the Gorter-Casimir form close to Tc.

  6. Cryogenic time-domain multiplexer based on SQUID arrays and superconducting/normal conducting switches

    Science.gov (United States)

    Beev, N.; Kiviranta, M.; van der Kuur, J.; Bruijn, M.; Brandel, O.; Linzen, S.; Fritzsch, L.; Ahoranta, J.; Penttilä, J.; Roschier, L.

    2014-05-01

    We have demonstrated the operation of a 12-channel Beyer-style SQUID-based time domain multiplexer. It was manufactured using a fabrication process that is cross-compatible between VTT and IPHT-Jena. The multiplexer consists of twelve 12-SQUID series arrays, each shunted by a Zappe-style interferometer array acting as a flux-controlled superconducting/normal conducting switch. By keeping all switches but one in the superconducting state, it is possible to select one active readout channel at a time. A flux feedback coil common to all SQUID arrays allows realization of a flux-locked loop. We present characteristics of the multiplexer and measurement data from experiments with a 25-pixel X-ray calorimeter array operated at T < 100 mK in a dilution refrigerator.

  7. [Determination of proximal chemical composition of squid (dosidicus gigas) and development of gel products].

    Science.gov (United States)

    Abugoch, L; Guarda, A; Pérez, L M; Paredes, M P

    1999-06-01

    The good nutritional properties of meat from big squid (Dosidicus gigas) living on the Chilean coast, was determined through its proximal composition 70 cal/100 g fresh meat; 82.23 +/- 0.98% moisture; 15.32 +/- 0.93% protein; 1.31 +/- 0.12% ashes; 0.87 +/- 0.18% fat and 0.27% NNE (non-nitrogen extract). The big squid meat was used to develop a gel product which contained NaCl and TPP. It was necessary to use additives for gel preparation, such as carragenin or alginate or egg albumin, due to the lack of gelation properties of squid meat. Formulations containing egg albumin showed the highest gel force measured by penetration as compared to those that contained carragenin or alginate.

  8. The jumbo squid, Dosidicus gigas (Ommastrephidae), living in oxygen minimum zones II: Blood-oxygen binding

    Science.gov (United States)

    Seibel, Brad A.

    2013-10-01

    Dosidicus gigas is a large, metabolically active squid that migrates across a strong oxygen and temperature gradient in the Eastern Pacific. Here we analyze the oxygen-binding properties of the squid's respiratory protein (hemocyanin, Hc) that facilitate such activity. A high Hc-oxygen affinity, strong temperature dependence, and pronounced pH sensitivity (P50=0.009T2.03, pH 7.4; Bohr coefficient=ΔlogP50/ΔpH=-1.55+0.034T) of oxygen binding facilitate night-time foraging in the upper water column, and support suppressed oxygen demand in hypoxic waters at greater depths. Expanding hypoxia may act to alter the species habitable depth range. This analysis supports the contention that ocean acidification could limit oxygen carrying capacity in squids at warmer temperature leading to reduced activity levels or altered distribution.

  9. Slow swimming, fast strikes: effects of feeding behavior on scaling of anaerobic metabolism in epipelagic squid.

    Science.gov (United States)

    Trueblood, Lloyd A; Seibel, Brad A

    2014-08-01

    Many pelagic fishes engage prey at high speeds supported by high metabolic rates and anaerobic metabolic capacity. Epipelagic squids are reported to have among the highest metabolic rates in the oceans as a result of demanding foraging strategies and the use of jet propulsion, which is inherently inefficient. This study examined enzymatic proxies of anaerobic metabolism in two species of pelagic squid, Dosidicus gigas and Doryteuthis pealeii (Lesueur 1821), over a size range of six orders of magnitude. We hypothesized that activity of the anaerobically poised enzymes would be high and increase with size as in ecologically similar fishes. In contrast, we demonstrate that anaerobic metabolic capacity in these organisms scales negatively with body mass. We explored several cephalopod-specific traits, such as the use of tentacles to capture prey, body morphology and reduced relative prey size of adult squids, that may create a diminished reliance on anaerobically fueled burst activity during prey capture in large animals.

  10. Meta-Atom Interactions and Coherent Response in rf SQUID Metamaterials

    Science.gov (United States)

    Trepanier, Melissa; Zhang, Daimeng; Mukhanov, Oleg; Jung, Philipp; Butz, Susanne; Koshelets, V. P.; Ustinov, Alexey; Anlage, Steven

    2015-03-01

    An rf SQUID (radio frequency superconducting quantum interference device) metamaterial can be modeled as an array of coupled nonlinear oscillators with resonant frequencies that are extremely tunable with temperature, dc magnetic field, and rf current. The metamaterial is driven by an external rf field and its response to that field defines its metamaterial characteristics. In the presence of disorder (nonuniform applied dc magnetic flux for instance) the SQUIDs may or may not oscillate coherently in response to the external rf field. Since we are interested in metamaterial applications, a strong coherent response is desirable. The coherence is affected by a variety of factors including flux uniformity, array size, degree of coupling, strength of the driving field, and uniformity in SQUID parameters. In this talk we will present experimental and simulation results exploring the effect of these parameters on coherence. This work is supported by the NSF-GOALI and OISE programs through Grant # ECCS-1158644, and CNAM.

  11. Failure Analysis of CCD Image Sensors Using SQUID and GMR Magnetic Current Imaging

    Science.gov (United States)

    Felt, Frederick S.

    2005-01-01

    During electrical testing of a Full Field CCD Image Senor, electrical shorts were detected on three of six devices. These failures occurred after the parts were soldered to the PCB. Failure analysis was performed to determine the cause and locations of these failures on the devices. After removing the fiber optic faceplate, optical inspection was performed on the CCDs to understand the design and package layout. Optical inspection revealed that the device had a light shield ringing the CCD array. This structure complicated the failure analysis. Alternate methods of analysis were considered, including liquid crystal, light and thermal emission, LT/A, TT/A SQUID, and MP. Of these, SQUID and MP techniques were pursued for further analysis. Also magnetoresistive current imaging technology is discussed and compared to SQUID.

  12. TEM measurement in a low resistivity overburden performed by using low temperature SQUID

    Science.gov (United States)

    Ji, Yanju; Du, Shangyu; Xie, Lijun; Chang, Kai; Liu, Yang; Zhang, Yi; Xie, Xiaoming; Wang, Yuan; Lin, Jun; Rong, Liangliang

    2016-12-01

    Exploration of areas with thick low resistivity overburden is still a challenge for time domain transient electromagnetic method (TEM). We report modeling of a sandwich-layered earth by simulating the B field response with different conductive target layer thicknesses, thus obtaining a relationship between the resolution of the B field and the exploration depth. A low temperature Superconducting Quantum Interference Device (SQUID) is an ideal sensor for measuring the secondary magnetic field B in TEM measurements, because its sensitivity of several fT/√Hz is independent of frequency. In our TEM experiments, we utilized two different coils as receivers, a simple SQUID system, and a large transmitter loop of 200 × 200 m2 to compare the detected decay curves. At some measurement points, a decay signal of more than 300 ms duration was obtained by using the SQUID. Apparent resistivity profiles of about 9 km length are presented.

  13. Analytical theory of DC SQUID with a resistively shunted inductance driven by thermal noises

    Institute of Scientific and Technical Information of China (English)

    Lü Hai-Feng; Gu Jiao; Huang Xin-Tang

    2005-01-01

    An analytical expression for the stationary probability distribution of the DC superconducting quantum interference device (SQUID) with a resistively shunted inductance driven by thermal noise is derived from the two-dimensional Fokker-Planck equation. The effects on the SQUID characteristics subject to a large thermal fluctuation with a noise parpameter г>0.20 are discussed by taking into account the thermal noise in the accuracy of numerical simulation. This theory is valid for a reduced inductance β≤1. The analytical formulae for the SQUID characteristics, e.g. the circulating current, the average voltage and the voltage modulation, are obtained and discussed. The theory shows that the voltage modulation increases with the shunted inductance more efficiently for a large inductance parameterβ and small fluctuation parpameterг.

  14. DC SQUID Spectrometers for Nuclear Quadrupole and Low-Field Nuclear Magnetic Resonance Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    TonThat, Dinh M. [Univ. of California, Berkeley, CA (United States)

    1998-04-01

    The dc Superconducting Quantum Interference Device (SQUJD) is a very sensitive detector of magnetic flux, with a typical flux noise of the order of 1 μΦ0Hz-1/2 at liquid helium temperature (Φ0=h/2e). This inherent flux sensitivity of the SQUID is used in a spectrometer for the detection of nuclear magnetic resonance (NMR.)and nuclear quadruple resonance (NQR). The processing magnetic field from the nuclear spins is coupled to the SQUID by mean of a flux transformer. The SQUID NMR spectrometer is used to measure the longitudinal relaxation time T1 of solid 129Xe at 4.2 K down to 0.1 mT.

  15. Monitoring geomagnetic signals of groundwater movement using multiple underground SQUID magnetometers

    Directory of Open Access Journals (Sweden)

    Henry S.

    2014-01-01

    Full Text Available Groundwater can influence the geomagnetic field measured underground in at least two key ways. The water levels in rock will determine its electrical conductivity, and thus change the magnitude of the telluric currents induced in the rock by changing magnetic fields generated in the ionosphere. This can be studied by using multiple magnetometers at different underground locations. Secondly the flow of water through rock will generate a small magnetic signal, of unknown magnitude, through the electrokinetic effect. SQUID magnetometry has the potential to allow passive studies of groundwater changes in complex systems such as karst. We have monitored geomagnetic signals using two SQUID magnetometers at the LSBB underground laboratory, and set an initial limit on the magnitude of the electrokinetic signal. We now plan to carry out a longer term measurement using three SQUID systems as well as fluxgate sensors to track changes in the gradient of the magnetic field across the underground complex.

  16. Impact of air gun noise on the behaviour of marine fish and squid.

    Science.gov (United States)

    Fewtrell, J L; McCauley, R D

    2012-05-01

    In this study various species of captive marine fish and one species of squid were exposed to the noise from a single air gun. Six trials were conducted off the coast of Western Australia with each trial using a different noise exposure regime. Noise levels received by the animals ranged between 120 and 184 dB re 1 μPa(2).s (SEL). Behavioural observations of the fish and squid were made before, during and after air gun noise exposure. Results indicate that as air gun noise levels increase, fish respond by moving to the bottom of the water column and swimming faster in more tightly cohesive groups. Significant increases in alarm responses were observed in fish and squid to air gun noise exceeding 147-151 dB re 1 μPa SEL. An increase in the occurrence of alarm responses was also observed as noise level increased.

  17. Non-destructive testing (NDT) of metal cracks using a high Tc rf-SQUID and eddy current method

    Energy Technology Data Exchange (ETDEWEB)

    Lu, D.F.; Fan, C.; Ruan, J.Z. [Midwest Superconductivity Inc., Lawrence, KS (United States)] [and others

    1994-12-31

    A SQUID is the most sensitive device to detect change in magnetic field. A non-destructive testing (NDT) device using high temperature SQUIDs and eddy current method will be much more sensitive than those currently used eddy current systems, yet much cheaper than one with low temperature SQUIDs. In this paper, we present our study of such a NDT device using a high temperature superconducting rf-SQUID as a gradiometer sensor. The result clearly demonstrates the expected sensitivity of the system, and indicates the feasibility of building a portable HTS SQUID NDT device with the help from cryocooler industry. Such a NDT device will have a significant impact on metal corrosion or crack detection technology.

  18. Effect of thermal processing and canning on cadmium and lead levels in California market squid: the role of metallothioneins.

    Science.gov (United States)

    Galitsopoulou, A; Georgantelis, D; Kontominas, M G

    2013-01-01

    The effects of two common seafood preparation practices (roasting and industrial canning) on the heavy metal content--cadmium (Cd) and lead (Pb)--of various tissues of California market squid were studied. Emphasis was placed on the role of metallothioneins (MT) in Cd and Pb behaviour during processing. Cd and Pb analysis was conducted by a Zeeman GTA-AAS atomic absorption spectrometry system; MT analysis was performed by a mercury saturation assay. Results showed that Cd levels in the mantle and whole squid were considerably affected by both processing practices, reaching a 240% increase in mantle and a 40% increase in whole squid. Interestingly, Cd behaviour was associated with MT changes during squid processing. On the other hand, Pb content was not affected from either processing or associated with MT content in the raw or processed squid. Therefore, processing operations may affect Cd and Pb content differently due to the specific metal bioaccumulation and chemical features of each heavy metal type.

  19. Comprehensive model of Jumbo squid Dosidicus gigas trophic ecology in the Northern Humboldt current system.

    Directory of Open Access Journals (Sweden)

    Ana Alegre

    Full Text Available The jumbo squid Dosidicus gigas plays an important role in marine food webs both as predator and prey. We investigated the ontogenetic and spatiotemporal variability of the diet composition of jumbo squid in the northern Humboldt Current system. For that purpose we applied several statistical methods to an extensive dataset of 3,618 jumbo squid non empty stomachs collected off Peru from 2004 to 2011. A total of 55 prey taxa was identified that we aggregated into eleven groups. Our results evidenced a large variability in prey composition as already observed in other systems. However, our data do not support the hypothesis that jumbo squids select the most abundant or energetic taxon in a prey assemblage, neglecting the other available prey. Indeed, multinomial model predictions showed that stomach fullness increased with the number of prey taxa, while most stomachs with low contents contained one or two prey taxa only. Our results therefore question the common hypothesis that predators seek locally dense aggregations of monospecific prey. In addition D. gigas consumes very few anchovy Engraulis ringens in Peru, whereas a tremendous biomass of anchovy is potentially available. It seems that D. gigas cannot reach the oxygen unsaturated waters very close to the coast, where the bulk of anchovy occurs. Indeed, even if jumbo squid can forage in hypoxic deep waters during the day, surface normoxic waters are then required to recover its maintenance respiration (or energy?. Oxygen concentration could thus limit the co-occurrence of both species and then preclude predator-prey interactions. Finally we propose a conceptual model illustrating the opportunistic foraging behaviour of jumbo squid impacted by ontogenetic migration and potentially constrained by oxygen saturation in surface waters.

  20. Comprehensive model of Jumbo squid Dosidicus gigas trophic ecology in the Northern Humboldt current system.

    Science.gov (United States)

    Alegre, Ana; Ménard, Frédéric; Tafur, Ricardo; Espinoza, Pepe; Argüelles, Juan; Maehara, Víctor; Flores, Oswaldo; Simier, Monique; Bertrand, Arnaud

    2014-01-01

    The jumbo squid Dosidicus gigas plays an important role in marine food webs both as predator and prey. We investigated the ontogenetic and spatiotemporal variability of the diet composition of jumbo squid in the northern Humboldt Current system. For that purpose we applied several statistical methods to an extensive dataset of 3,618 jumbo squid non empty stomachs collected off Peru from 2004 to 2011. A total of 55 prey taxa was identified that we aggregated into eleven groups. Our results evidenced a large variability in prey composition as already observed in other systems. However, our data do not support the hypothesis that jumbo squids select the most abundant or energetic taxon in a prey assemblage, neglecting the other available prey. Indeed, multinomial model predictions showed that stomach fullness increased with the number of prey taxa, while most stomachs with low contents contained one or two prey taxa only. Our results therefore question the common hypothesis that predators seek locally dense aggregations of monospecific prey. In addition D. gigas consumes very few anchovy Engraulis ringens in Peru, whereas a tremendous biomass of anchovy is potentially available. It seems that D. gigas cannot reach the oxygen unsaturated waters very close to the coast, where the bulk of anchovy occurs. Indeed, even if jumbo squid can forage in hypoxic deep waters during the day, surface normoxic waters are then required to recover its maintenance respiration (or energy?). Oxygen concentration could thus limit the co-occurrence of both species and then preclude predator-prey interactions. Finally we propose a conceptual model illustrating the opportunistic foraging behaviour of jumbo squid impacted by ontogenetic migration and potentially constrained by oxygen saturation in surface waters.

  1. Comprehensive Model of Jumbo Squid Dosidicus gigas Trophic Ecology in the Northern Humboldt Current System

    Science.gov (United States)

    Alegre, Ana; Ménard, Frédéric; Tafur, Ricardo; Espinoza, Pepe; Argüelles, Juan; Maehara, Víctor; Flores, Oswaldo; Simier, Monique; Bertrand, Arnaud

    2014-01-01

    The jumbo squid Dosidicus gigas plays an important role in marine food webs both as predator and prey. We investigated the ontogenetic and spatiotemporal variability of the diet composition of jumbo squid in the northern Humboldt Current system. For that purpose we applied several statistical methods to an extensive dataset of 3,618 jumbo squid non empty stomachs collected off Peru from 2004 to 2011. A total of 55 prey taxa was identified that we aggregated into eleven groups. Our results evidenced a large variability in prey composition as already observed in other systems. However, our data do not support the hypothesis that jumbo squids select the most abundant or energetic taxon in a prey assemblage, neglecting the other available prey. Indeed, multinomial model predictions showed that stomach fullness increased with the number of prey taxa, while most stomachs with low contents contained one or two prey taxa only. Our results therefore question the common hypothesis that predators seek locally dense aggregations of monospecific prey. In addition D. gigas consumes very few anchovy Engraulis ringens in Peru, whereas a tremendous biomass of anchovy is potentially available. It seems that D. gigas cannot reach the oxygen unsaturated waters very close to the coast, where the bulk of anchovy occurs. Indeed, even if jumbo squid can forage in hypoxic deep waters during the day, surface normoxic waters are then required to recover its maintenance respiration (or energy?). Oxygen concentration could thus limit the co-occurrence of both species and then preclude predator-prey interactions. Finally we propose a conceptual model illustrating the opportunistic foraging behaviour of jumbo squid impacted by ontogenetic migration and potentially constrained by oxygen saturation in surface waters. PMID:24465788

  2. Magnetic field imaging of a tungsten carbide film by scanning nano-SQUID microscope

    Science.gov (United States)

    Shibata, Yusuke; Nomura, Shintaro; Ishiguro, Ryosuke; Kashiwaya, Hiromi; Kashiwaya, Satoshi; Nago, Yusuke; Takayanagi, Hideaki

    2016-10-01

    We present the results of magnetic field imaging by scanning nano-superconducting quantum interference device (SQUID) microscopy on a tungsten carbide (W-C) film fabricated using focused-ion-beam chemical vapor deposition. We have investigated magnetic field change by a W-C film in an external magnetic field using a scanning nano-SQUID microscope system. We have found that the reduction of the magnetic field above the W-C film was 0.9%, indicating the penetration of vortices in the W-C at an external magnetic field of 0.171 mT.

  3. Isolation and Characterization of Collagen from Squid(Ommastreoges bartrami) Skin

    Institute of Scientific and Technical Information of China (English)

    YAN Mingyan; LI Bafang; ZHAO Xue

    2009-01-01

    Collagen of squid (Ommastrephes bartrami) skin was examined in the present study. Histology showed that collagen fiber in the skin was partially cross-linked with muscle fiber. Acid-solubilized collagen (ASC) and pepsin-solubilized collagen (PSC) were extracted from the skin and characterized. The results of amino acid composition and electrophoretic patterns revealed that ASC and PSC were both type Ⅰ collagen, containing α1 and α2 chains. FTIR (fourier transform infrared spectroscopy) investigations con-firmed the existence of helical arrangements in PSC of squid skin. The denaturation temperature (Td) and shrinkage temperature (Ts)of PSC were 29.4℃ and 52.8℃, respectively.

  4. Comparison of Ising spin glass noise to flux and inductance noise in SQUIDs.

    Science.gov (United States)

    Chen, Zhi; Yu, Clare C

    2010-06-18

    Recent experiments implicate spins on the surface of metals as the source of flux and inductance noise in SQUIDs. We present Monte Carlo simulations of 2D and 3D Ising spin glasses that produce magnetization noise S(M) consistent with flux noise. At low frequencies S(M) is a maximum at the critical temperature T(C) in three dimensions, implying that flux noise should be a maximum at T(C). The second spectra of the magnetization noise and the noise in the susceptibility are consistent with experimentally measured SQUID inductance noise.

  5. Modeling the Effects of Varying the Capacitance, Resistance, Temperature, and Frequency Dependence for HTS Josephson Junctions, DC SQUIDs and DC bi-SQUIDS

    Science.gov (United States)

    2014-09-01

    junction is a thin layer of insulating material sep- arating two superconductors that is thin enough for electrons to tunnel through. Two Josephson...different material and/or method on the bisecting Josephson junction for high temperature superconductor (HTS) YBa2Cu3O7 (YBCO) bi-SQUIDs. This...in the previous case. The transition point (critical current) and hysteresis are both decreased. There are much greater amplitude oscillations for K P

  6. Verification of the weak equivalence principle of supports and heavy masses using SQUIDs; Ueberpruefung des schwachen Aequivalenzprinzips von Traegern und schwerer Masse mittels Squids

    Energy Technology Data Exchange (ETDEWEB)

    Vodel, W.; Nietzsche, S.; Neubert, R. [Friedrich-Schiller-Universitaet Jena (Germany). Inst. fuer Festkoerperphysik; Dittus, H. [Univ. Bremen (Germany). Zentrum fuer angewandte Raumfahrttechnologie und Mikrogravitation

    2003-07-01

    The weak equivalence principle is one of the fundamental hypotheses of general relativity and one of the key elements of our physical picture of the world, but since Galileo there has been no satisfactory way of verifying it. The new SQUID technology may offer a solution. The contribution presents the experiments of Jena University. Applications are envisaged, e.g., in the STEP space mission of the NASA/ESA. [German] Das Schwache Aequivalenzprinzip ist eine der grundlegenden Hypothesen der Allgemeinen Relativitaetstheorie und damit einer der Grundpfeiler unseres physikalischen Weltbildes. Obwohl es seit den ersten Experimenten von Galileo Galilei am Schiefen Turm zu Pisa im Jahre 1638 bis heute schon zahlreiche und immer praeziser werdende Messungen zur Ueberpruefung der Aequivalenz von schwerer und traeger Masse gegeben hat, ist die strenge Gueltigkeit dieses fundamentalen Prinzips experimentell vergleichsweise unzureichend bestimmt. Neuere Methoden, wie der Einsatz SQUID-basierter Messtechnik und die Durchfuehrung von Experimenten auf Satelliten, lassen Verbesserungen schon in naher Zukunft erwarten, so dass theoretische Ueberlegungen zur Vereinigung aller uns bekannten physikalischen Wechselwirkungen, die eine Verletzung des Schwachen Aequivalenzprinzips voraussagen, experimentell eingegrenzt werden koennten. Der Beitrag gibt einen Ueberblick ueber die an der Universitaet Jena entwickelte SQUID-basierte Messtechnik zum Test des Aequivalenzprinzips und fasst die bisher bei Freifallversuchen am Fallturm Bremen erzielten experimentellen Ergebnisse zusammen. Ein Ausblick auf die geplante Raumfahrtmission STEP der NASA/ESA zum Praezisionstest des Schwachen Aequivalenzprinzips schliesst den Beitrag ab. (orig.)

  7. Cadmium content in fresh and canned squid (Loligo opalescens) from the Pacific coastal waters of California (USA).

    Science.gov (United States)

    Galitsopoulou, A; Georgantelis, D; Kontominas, M G

    2009-01-01

    Cadmium (Cd) levels were determined in 70 samples of mantle tissue and 70 whole individual squid (Loligo opalescens; commercially known as California squid). Samples were collected from the coastal zones of California (USA) during the period 2007/2008. To further investigate consumer exposure to processed fishery products, cadmium concentration was also determined in 200 canned samples of squid. Cd concentrations in raw mantle were low, between 0.01 and 0.29 mg kg(-1) and below the tolerance limit of current regulations (1 mg kg(-1)). Respective concentrations in whole individuals were significantly higher, ranging from 0.51 to 1.18 mg kg(-1), attributed to the presence of the visceral portion in whole squid samples. Cd concentrations varied in relation to age and sex of squid, indicating that several physiological factors may influence accumulation. Furthermore, canning of squid substantially enhanced Cd levels. Cd concentration ranged 0.17-0.67 mg kg(-1) in canned mantle tissue and 0.86-2.07 mg kg(-1) in canned whole squid samples, due to both concentration after canning and movement of the metal between different tissues. Several biological compounds, including metallothioneins, nucleic acids and enzymes, may affect Cd concentrations in commercial fishery products.

  8. Characterization of single-core magnetite nanoparticles for magnetic imaging by SQUID relaxometry.

    Science.gov (United States)

    Adolphi, Natalie L; Huber, Dale L; Bryant, Howard C; Monson, Todd C; Fegan, Danielle L; Lim, Jitkang; Trujillo, Jason E; Tessier, Trace E; Lovato, Debbie M; Butler, Kimberly S; Provencio, Paula P; Hathaway, Helen J; Majetich, Sara A; Larson, Richard S; Flynn, Edward R

    2010-10-07

    Optimizing the sensitivity of SQUID (superconducting quantum interference device) relaxometry for detecting cell-targeted magnetic nanoparticles for in vivo diagnostics requires nanoparticles with a narrow particle size distribution to ensure that the Néel relaxation times fall within the measurement timescale (50 ms-2 s, in this work). To determine the optimum particle size, single-core magnetite nanoparticles (with nominal average diameters 20, 25, 30 and 35 nm) were characterized by SQUID relaxometry, transmission electron microscopy, SQUID susceptometry, dynamic light scattering and zeta potential analysis. The SQUID relaxometry signal (detected magnetic moment/kg) from both the 25 nm and 30 nm particles was an improvement over previously studied multi-core particles. However, the detected moments were an order of magnitude lower than predicted based on a simple model that takes into account the measured size distributions (but neglects dipolar interactions and polydispersity of the anisotropy energy density), indicating that improved control of several different nanoparticle properties (size, shape and coating thickness) will be required to achieve the highest detection sensitivity. Antibody conjugation and cell incubation experiments show that single-core particles enable a higher detected moment per cell, but also demonstrate the need for improved surface treatments to mitigate aggregation and improve specificity.

  9. Magnetic properties of thin Ni films measured by a dc SQUID-based magnetic microscope

    DEFF Research Database (Denmark)

    Snigirev, O.V.; Andreev, K.E.; Tishin, A.M.;

    1997-01-01

    We have applied a scanning HTS (high-temperature superconductor) de SQUID (superconducting quantum interference device) -based magnetic microscope to study the magnetic properties of Au/Ni/Si(100) films in the thickness range from 8 to 200 Angstrom at T = 77 K. A one-domain structure with in-plan...

  10. Reversible stress softening of collagen based networks from the jumbo squid mantle (Dosidicus gigas)

    Energy Technology Data Exchange (ETDEWEB)

    Torres, F.G., E-mail: fgtorres@pucp.edu.pe [Department of Mechanical Engineering, Catholic University of Peru, Lima 32 (Peru); Troncoso, O.P.; Rivas, E.R. [Department of Mechanical Engineering, Catholic University of Peru, Lima 32 (Peru); Gomez, C.G. [Departament de Química Física and Institut de Ciencia dels Materials, Universitat de València, Dr. Moliner 50, Burjassot, E-46100 Valencia (Spain); Lopez, D. [Instituto de Ciencia y Tecnología de Polímeros, C.S.I.C., Calle Juan de la Cierva 3, 28006 Madrid (Spain)

    2014-04-01

    Dosidicus gigas is the largest and one of the most abundant jumbo squids in the eastern Pacific Ocean. In this paper we have studied the muscle of the mantle of D. gigas (DGM). Morphological, thermal and rheological properties were assessed by means of atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential scanning calorimetry, thermogravimetry and oscillatory rheometry. This study allowed us to assess the morphological and rheological properties of a collagen based network occurring in nature. The results showed that the DGM network displays a nonlinear effect called reversible stress softening (RSS) that has been previously described for other types of biological structures such as naturally occurring cellulose networks and actin networks. We propose that the RSS could play a key role on the way jumbo squids withstand hydrostatic pressure. The results presented here confirm that this phenomenon occurs in a wider number of materials than previously thought, all of them exhibiting different size scales as well as physical conformation. - Highlights: • We studied the structure property relationships of the jumbo squid mantle. • Rheological tests showed that such a mantle exhibits reversible stress softening (RSS). • RSS could also play a role on the way jumbo squids withstand hydrostatic pressure.

  11. Development of non-hysteretic unshunted rf-SQUIDs for multiplexed MMC readout

    Energy Technology Data Exchange (ETDEWEB)

    Kempf, S.; Fleischmann, A.; Gastaldo, L.; Heuser, S.; Kampkoetter, A.; Pies, C.; Porst, J.P.; Ranitzsch, P.; Schaefer, S.; Vick, S.; Wolf, T.; Enss, C. [Kirchhoff Institute for Physics, Heidelberg University (Germany)

    2011-07-01

    Metallic magnetic calorimeters (MMCs) are energy dispersive particle detectors with a high resolving power that are operated at temperatures below 100 mK. Presently single channel MMCs are proving to be promising detectors in areas diverse as atomic and nuclear physics or X-ray astronomy, while many of those experiments would greatly benefit from large detector arrays. However, array readout poses a significant challenge since a multiplexing scheme is required. A promising approach employs a microwave SQUID multiplexer consisting of non-hysteretic unshunted rf-SQUIDs that are coupled to high Q tank circuits with unique resonance frequencies. By coupling all tank circuits to a common transmission line and injecting a microwave frequency comb it is possible to monitor all detectors simultaneously. We discuss design, fabrication and operation of a microwave SQUID multiplexer for the readout of MMC detector arrays. For our present devices we used SNEAP to produce micron-size Nb/Al-AlO{sub x}/Nb Josephson junctions with low critical current densities. The quality of the fabricated Josephson junctions is discussed. Finally we outline the expected performance of a detector array that is read out with the designed SQUID multiplexer as derived from numerical optimization calculations.

  12. Squid 'ear bones' (statoliths) from the Jurassic succession of South-west England

    Science.gov (United States)

    Hart, Malcolm; Page, Kevin; Price, Gregory; Smart, Christopher

    2015-04-01

    Squid 'ear bones' - or statoliths - are a part of the balancing organs of modern and probably most fossil squids. Over the course of the last 10 years fossil statoliths have been discovered in the Jurassic sediments of the Wessex Basin (South-west England). They are probably all related to teuthids, such as Belemnotheutis antiquus Pearce, of Callovian-Oxfordian age. Thus far, we have identified four possible 'species' of statolith that are in the process of being formally described, named and their potential relationships determined. The sediments from which these statoliths have been recorded also contain squid hooklets (onycites), otoliths (fish 'ear bones') and other microfossils (including foraminifera). All are, therefore, of marine origin. In the case of the Christian Malford and Ashton Keynes lagerstätte (of late Callovian age), the statoliths are associated with exceptional, soft-bodied preservation of squid and it may be possible to determine the parent animal of the recorded statoliths. A number of museum collections (Natural History Museum [London], Natural History Museum [Paris], Senckenberg [Frankfurt], Smithsonian Institution [Washington], etc.) are being investigated in order to trace the possible host animals for all of the recorded statoliths. Despite many thousands of samples of Cretaceous sediments being investigated for foraminifera over the past 40+ years, no statoliths have been recorded and none are known from the literature.

  13. Closed-cycle gas flow system for cooling of high Tc d.c. SQUID magnetometers

    NARCIS (Netherlands)

    Bosch, van den P.J.; Holland, H.J.; Brake, ter H.J.M.; Rogalla, H.

    1995-01-01

    A high Tc.d.c SQUID based magnetometer for magnetocardiography is currently under development at the University of Twente. Since such a magnetometer should be simple to use, the cooling of the system can be realized most practically by means of a cryocooler. A closed-cycle gas flow cooling system in

  14. Dynamical effects of an unconventional current-phase relation in YBCO dc SQUIDs.

    Science.gov (United States)

    Lindström, T; Charlebois, S A; Tzalenchuk, A Ya; Ivanov, Z; Amin, M H S; Zagoskin, A M

    2003-03-21

    The predominant d-wave pairing symmetry in high-temperature superconductors allows for a variety of current-phase relations in Josephson junctions, which is to a certain degree fabrication controlled. In this Letter, we report on direct experimental observations of the effects of a nonsinusoidal current-phase dependence in YBCO dc SQUIDs, which agree with the theoretical description of the system.

  15. Comparison live adult Artemia and squid meat on the growth of Penaeid shrimp Metapenaeus dobsoni (Miers)

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.R.S.; Achuthankutty, C.T.; Royan, J.P.

    An experiment lasting 14 weeks was conducted to compare the efficiency of live adult Artemia with fresh squid meat on growth of penaeid shrimp Metapenaeus dobsoni. The shrimps were found actively feeding on live Artemia and grew 84% more than those...

  16. Measurement of fMCG Signals using an Axial Type First-Order SQUID Gradiometer System

    Energy Technology Data Exchange (ETDEWEB)

    Yu, K. K.; Kim, K.; Kang, C. S.; Kim, J. M.; Lee, Y. H. [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2009-04-15

    We have fabricated a low-noise 61-channel axial-type first-order gradiometer system for measuring fetal magnetocardiography(MCG) signals. Superconducting quantum interference device(SQUID) sensor was based on double relaxation oscillation SQUID(DROS) for detecting biomagnetic signal, such as MCG, magnetoencphalogram(MEG) and fetal-MCG. The SQUID sensor detected axial component of fetal MCG signal. The pickup coil of SQUID sensor was wound with 120 {mu}m NbTi wire on bobbin(20 mm diameter) and was a first-order gradiometer to reject the environment noise. The sensors have low white noise of 3 fT/Hz{sup 1/2} at 100 Hz on average. The fetal MCG was measured from 24 - 36 weeks fetus in a magnetically shielded room(MSR) with shielding factor of 35 dB at 0.1 Hz and 80 dB at 100 Hz(comparatively mild shielding). The MCG signal contained maternal and fetal MCG. Fetal MCG could be distinguished relatively easily from maternal MCG by using independent component analysis(ICA) filter. In addition, we could observe T peak as well as QRS wave, respectively. It will be useful in detecting fetal cardiac diseases.

  17. A high-Tc SQUID-based sensor head cooled by a Joule–Thomson cryocooler

    NARCIS (Netherlands)

    Rijpma, A.P.; Brake, ter H.J.M.; Vries, de E.; Nijhof, N.; Holland, H.J.; Rogalla, H.

    2002-01-01

    The goal of the so-called FHARMON project is to develop a high-Tc SQUID-based magnetometer system for the measurement of fetal heart activity in standard clinical environments. To lower the threshold for the application of this fetal heart monitor, it should be simple to operate. It is, therefore, a

  18. Measurement of SQUID noise levels for SuperCDMS SNOLAB detectors - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Maxwell [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    SuperCDMS SNOLAB is a second generation direct dark matter search. In the SuperCDMS SNOLAB experiment, detectors are able to pick up from signals from dark matter nuclear recoil interactions which occur inside the bulk of the detectors. These interactions produce both phonon and charge signals. HEMTs read out charge signals whereas TES are used to detect phonon signals which are then read out by SQUID amplifiers. SQUID amplifiers must add negligible noise to the TES intrinsic noise which has been previously measured and is approximately 50pA/√Hz down to 100Hz for ease of signal distinguishability in dark matter nuclear interactions. The intrinsic noise level of the SQUID was tested in the SLAC 300mK fridge and determined to provide adequately low levels of noise with a floor of approximately 3pA/√Hz. Furthermore, a 10x amplifier was tested for addition of extraneous noise. This noise was investigated with and without this amplifier, and it was found that it did not add a significant amount of noise to the intrinsic SQUID noise.

  19. A broadband dc SQUID based rf amplifier: experimental basics and development concept

    DEFF Research Database (Denmark)

    Prokopenko, G.V.; Shitov, S.V.; Mygind, Jesper

    2002-01-01

    We present a concept of a broadband IF amplifier based on experimental results obtained with a dc SQUID rf amplifier (SQA). The frequency range is broadened by using several SQAs, each one tuned to its own central frequency at both input and output; the numerical simulations are presented...

  20. Sphingoid esters from the molecular distillation of squid oil: A preliminary bioactivity determination.

    Science.gov (United States)

    Saliu, Francesco; Longhin, Eleonora; Salanti, Anika; Degano, Ilaria; Della Pergola, Roberto

    2016-06-15

    A mixture of sphingoid esters was isolated (1.4% w/w) from the molecular distillation of crude squid visceral oil. A preliminary investigation on the bioactivity profile and toxic potential of this residue was carried out by in vitro experiments. No cytotoxicity and a moderate lipase inhibition activity were highlighted.

  1. Characterization of single-core magnetite nanoparticles for magnetic imaging by SQUID relaxometry

    Energy Technology Data Exchange (ETDEWEB)

    Adolphi, Natalie L [Department of Biochemistry and Molecular Biology, University of New Mexico, Albuquerque, NM 87131 (United States); Huber, Dale L; Monson, Todd C; Provencio, Paula P [Sandia National Laboratories, P. O. Box 5800, Albuquerque, NM 87185 (United States); Bryant, Howard C; Fegan, Danielle L; Tessier, Trace E; Flynn, Edward R [Senior Scientific, LLC, 11109 Country Club NE, Albuquerque, NM 87111 (United States); Lim, JitKang; Majetich, Sara A [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Trujillo, Jason E; Lovato, Debbie M; Butler, Kimberly S; Larson, Richard S [Department of Pathology, Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM 87131 (United States); Hathaway, Helen J, E-mail: NAdolphi@salud.unm.ed [Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM 87131 (United States)

    2010-10-07

    Optimizing the sensitivity of SQUID (superconducting quantum interference device) relaxometry for detecting cell-targeted magnetic nanoparticles for in vivo diagnostics requires nanoparticles with a narrow particle size distribution to ensure that the Neel relaxation times fall within the measurement timescale (50 ms-2 s, in this work). To determine the optimum particle size, single-core magnetite nanoparticles (with nominal average diameters 20, 25, 30 and 35 nm) were characterized by SQUID relaxometry, transmission electron microscopy, SQUID susceptometry, dynamic light scattering and zeta potential analysis. The SQUID relaxometry signal (detected magnetic moment/kg) from both the 25 nm and 30 nm particles was an improvement over previously studied multi-core particles. However, the detected moments were an order of magnitude lower than predicted based on a simple model that takes into account the measured size distributions (but neglects dipolar interactions and polydispersity of the anisotropy energy density), indicating that improved control of several different nanoparticle properties (size, shape and coating thickness) will be required to achieve the highest detection sensitivity. Antibody conjugation and cell incubation experiments show that single-core particles enable a higher detected moment per cell, but also demonstrate the need for improved surface treatments to mitigate aggregation and improve specificity.

  2. Materials aspects of integrated high-Tc dc-SQUID magnetometer fabrication

    NARCIS (Netherlands)

    Hilgenkamp, J.W.M.; IJsselsteijn, R.P.J.; Rijnders, A.J.H.M.; Tavares, P.A.C.; Flokstra, J.; Rogalla, H.

    1993-01-01

    An integrated high Tc dc-SQUID magnetometer is being developed. It has in total 10 layers of five different materials. Various materials aspects of the fabrication process will be discussed, especially the smoothness of the films and the techniques to obtain smooth edges. Cross-overs and superconduc

  3. SQUID-based rock magnetometer with open-ended horizontal roomtemperature access

    NARCIS (Netherlands)

    Brake, ter H.J.M.; Court, de la P.; Lenferink, A.T.M.; Ulfman, J.A.; Flokstra, J.

    1987-01-01

    We constructed a 3-channel SQUID-based rock magnetometer with an open-ended horizontal room-temperature access having an inner diameter of 38 mm. A refrigerator is incorporated for cooling two radiation shields so that an operating time can be realized of about 10 weeks with a reservoir volume of 26

  4. Mitochondrial genome diversity and population structure of the giant squid Architeuthis

    DEFF Research Database (Denmark)

    Winkelmann, Inger; Campos, Paula F; Strugnell, Jan

    2013-01-01

    Despite its charismatic appeal to both scientists and the general public, remarkably little is known about the giant squid Architeuthis, one of the largest of the invertebrates. Although specimens of Architeuthis are becoming more readily available owing to the advancement of deep-sea fishing...

  5. High Sensitivity Magnetic Flux Sensors with Direct Voltage Readout Double Relaxation Oscillation SQUIDs

    NARCIS (Netherlands)

    Adelerhof, D.J.; Duuren, van M.J.; Flokstra, J.; Rogalla, H.; Kawai, J.; Kado, H.

    1995-01-01

    The experimental sensitivity of double relaxation oscillation SQUIDs (DROSs) has been compared with theory and with the results obtained by numerical simulations. The experimental sensitivity ranges from 60 to 13h, where h is Planck's constant, for relaxation frequencies from 0.4 up to 10 GHz. For l

  6. Relation between quantum NOT gate speed and asymmetry of the potential of RF-SQUID

    Institute of Scientific and Technical Information of China (English)

    Ji Ying-Hua; Cai Shi-Hua; Hu Ju-Ju

    2008-01-01

    This paper investigates the relationship between the speed of a quantum not gate and the asymmetry of the potential in an interactive system formed by a two-level RF-SQUID qubit and a classical microwave pulse.The RF-SQUID is characterized by an asymmetric double well potential which gives rise to diagonal matrix elements that describe the interaction of the SQUID with the microwave pulse.And the diagonal matrix elements account for the interaction of the microwave pulse with the SQUID.The results indicate that,when the angular frequency of the microwave field is chosen as near resonate with the transition |0>(→) |1>,i.e.ω1-ω0 ≈ωm,(1) the gate speed is decided by three factors,the Rabi frequency,the difference of the diagonal matrix elements between the two levels,and the angular frequency of the applied microwave pulse Wm;(2) the gate speed descends when the asymmetry of the potential is considered.

  7. SQUID magnetometer using sensitivity correction signal for non-magnetic metal contaminants detection

    Science.gov (United States)

    Yagi, Toshifumi; Ohashi, Masaharu; Sakuta, Ken

    2016-11-01

    Measurement methods with SQUID can accurately detect small magnetic metal contaminants based on their magnetic remanence. But, a high-frequency excitation is necessary to detect nonmagnetic metals, on the base of contrasts in electric conductivity. In this work, an open loop technique is introduced to facilitate this. The SQUID is negative feedback controlled (flux locked loop (FLL) operation) for the low frequency range, which includes significant noise due to the movement of the magnetic body or the change of the ambient magnetic field composed of the geomagnetic field and technical signals, and it operates in an open loop configuration for the high frequency range. When using the open loop technique, negative feedback is not applied to the high frequency range. Consequently, the V-Φ characteristic changes due to various causes, which leads to variations in the conversion factor between the SQUID output voltage and the magnetic field. In this study, conversion techniques for the magnetic field for open loop operation of SQUID in the high frequency range are examined.

  8. A complementary least-mean-square algorithm of adaptive filtering for SQUID based magnetocardiography

    Institute of Scientific and Technical Information of China (English)

    Li Zhuo; Chen Geng-Hua; Zhang Li-Hua; Yang Qian-Sheng; Feng Ji

    2005-01-01

    We present acomplementary least-mean-square algorithm of adaptive filtering for SQUID-based magnetocardiography, in which both rapid convergence and fine tracking are realized by switching the weight parameters back and forth between two filters according to the least mean square principle.

  9. 77 FR 74159 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2012-12-13

    ... Adjustment 7, are available from: Dr. Christopher M. Moore, Executive Director, Mid-Atlantic Fishery... Mackerel, Squid, and Butterfish (MSB) Fishery Management Plan (FMP) (75 FR 11441, March 11, 2010) as a...: December 10, 2012. Alan Risenhoover, Director, Office of Sustainable Fisheries, performing the...

  10. The giant eyes of giant squid are indeed unexpectedly large, but not if used for spotting sperm whales

    OpenAIRE

    Nilsson, Dan-E; Warrant, Eric J.; Johnsen, Sönke; Hanlon, Roger T.; Shashar, Nadav

    2013-01-01

    Background We recently reported (Curr Biol 22:683–688, 2012) that the eyes of giant and colossal squid can grow to three times the diameter of the eyes of any other animal, including large fishes and whales. As an explanation to this extreme absolute eye size, we developed a theory for visual performance in aquatic habitats, leading to the conclusion that the huge eyes of giant and colossal squid are uniquely suited for detection of sperm whales, which are important squid-predators in the dep...

  11. The biology and ecology of the jumbo squid Dosidicus gigas (Cephalopoda in Chilean waters: a review

    Directory of Open Access Journals (Sweden)

    Christian M Ibáñez

    2015-07-01

    Full Text Available ABSTRACT. The jumbo squid Dosidicus gigas is the most abundant cephalopod species in the southeastern Pacific Ocean, which supports the biggest cephalopod fishery in the world. Due to its growing economic importance, the population growth and distributional expansion of this squid is being increasingly studied. Nevertheless, some basic features of the biology of D. gigas are still unknown or have been poorly investigated. In this review we summarize the known information regarding the biology and ecology of this species in the southeastern Pacific Ocean; we focus on the Chilean region in order to propose hypotheses and research lines for a better understanding the life history of this organism. Available data on the size structure, reproduction and genetics of D. gigas allows us to propose hypotheses related to the squid's life history traits. Based on the current literature and publications of colleagues, we propose two hypotheses regarding the effect of spatial variation on the life history of D. gigas. Hypothesis 1: Squids mature at large sizes and spawn in oceanic waters with warm temperatures where paralarvae and juveniles develop. Immature squids migrate near shore to feed, grow and mature, and then return to the offshore sites to spawn. Hypothesis 2: Alternatively, juvenile D. gigas in the oceanic zone do not migrate to coastal waters and mature at small sizes compared to individuals living near the coast that mature at larger size and migrate to oceanic waters to spawn. We provide background information about the feeding behavior and parasitism of this species, suggesting that D. gigas is an important trophic link in the southeastern Pacific marine ecosystem. However, more studies on the feeding habits, reproduction and parasite load are needed not only to test hypotheses proposed in this study, but also to advance the overall knowledge of this species.

  12. Sequential isotopic signature along gladius highlights contrasted individual foraging strategies of jumbo squid (Dosidicus gigas.

    Directory of Open Access Journals (Sweden)

    Anne Lorrain

    Full Text Available BACKGROUND: Cephalopods play a major role in marine ecosystems, but knowledge of their feeding ecology is limited. In particular, intra- and inter-individual variations in their use of resources has not been adequatly explored, although there is growing evidence that individual organisms can vary considerably in the way they use their habitats and resources. METHODOLOGY/PRINCIPAL FINDINGS: Using δ(13C and δ(15N values of serially sampled gladius (an archival tissue, we examined high resolution variations in the trophic niche of five large (>60 cm mantle length jumbo squids (Dosidicus gigas that were collected off the coast of Peru. We report the first evidence of large inter-individual differences in jumbo squid foraging strategies with no systematic increase of trophic level with size. Overall, gladius δ(13C values indicated one or several migrations through the squid's lifetime (∼8-9 months, during which δ(15N values also fluctuated (range: 1 to 5‰. One individual showed an unexpected terminal 4.6‰ δ(15N decrease (more than one trophic level, thus indicating a shift from higher- to lower-trophic level prey at that time. The data illustrate the high diversity of prey types and foraging histories of this species at the individual level. CONCLUSIONS/SIGNIFICANCE: The isotopic signature of gladii proved to be a powerful tool to depict high resolution and ontogenic variations in individual foraging strategies of squids, thus complementing traditional information offered by stomach content analysis and stable isotopes on metabolically active tissues. The observed differences in life history strategies highlight the high degree of plasticity of the jumbo squid and its high potential to adapt to environmental changes.

  13. Fishery Biology of Jumbo Flying Squid Dosidicus gigas off Costa Rica Dome

    Institute of Scientific and Technical Information of China (English)

    CHEN Xinjun; LI Jianghua; LIU Bilin; LI Gang; LU Huajie

    2014-01-01

    The jumbo flying squid (Dosidicus gigas) population was surveyed with the help of Chinese squid jigging vessels off the Costa Rica Dome (4˚-11˚N, 90˚-100˚W) in 2009 and 2010. The daily catch of D. gigas in the two survey cruises ranged from 0 to 5.5 t and was mostly obtained from the areas bounded by 6˚-9˚N and 91˚-94˚W and by 6˚30´-7˚30´N and 96˚-97˚W. The sea surface temperature in the areas yielding the most catch ranged from 27.5 to 29℃. The sex ratio of the total catch was 3.75:1 (female:male). The mantle length of the squid ranged from 211 to 355 mm (male) and from 204 to 429 mm (female) with an average of 297.9 and 306.7 mm, respectively. In the relationship of the mantle length (mm) and body weight (g) of the squid, there was no significant dif-ference between sexes. The female and male were at a similar maturity, and most individuals are maturing or have matured with a few females being spent. The size (mantle length) and age at the first sexual maturity were 297 mm and 195 d in females, and less than 211 mm and 130 d in males, respectively. Most of the sampled stomachs (70.6%) had no food remains. The major preys of the squids were fish, cephalopods and crustaceans, with the most abundant Myctophum orientale and D. gigas. The preys in more than 65%of the non-empty sampled stomachs evidenced the cannibalism of D. gigas. The results improved current understanding of the fishery biology of D. gigas off the Costa Rica Dome, which may facilitate the assessment and management of relative fishery re-sources.

  14. Fishery biology of jumbo flying squid Dosidicus gigas off Costa Rica Dome

    Science.gov (United States)

    Chen, Xinjun; Li, Jianghua; Liu, Bilin; Li, Gang; Lu, Huajie

    2014-06-01

    The jumbo flying squid ( Dosidicus gigas) population was surveyed with the help of Chinese squid jigging vessels off the Costa Rica Dome (4°-11°N, 90°-100°W) in 2009 and 2010. The daily catch of D. gigas in the two survey cruises ranged from 0 to 5.5 t and was mostly obtained from the areas bounded by 6°-9°N and 91°-94°W and by 6°30'-7°30'N and 96°-97°W. The sea surface temperature in the areas yielding the most catch ranged from 27.5 to 29°C. The sex ratio of the total catch was 3.75:1 (female: male). The mantle length of the squid ranged from 211 to 355 mm (male) and from 204 to 429 mm (female) with an average of 297.9 and 306.7 mm, respectively. In the relationship of the mantle length (mm) and body weight (g) of the squid, there was no significant difference between sexes. The female and male were at a similar maturity, and most individuals are maturing or have matured with a few females being spent. The size (mantle length) and age at the first sexual maturity were 297 mm and 195 d in females, and less than 211 mm and 130 d in males, respectively. Most of the sampled stomachs (70.6%) had no food remains. The major preys of the squids were fish, cephalopods and crustaceans, with the most abundant Myctophum orientale and D. gigas. The preys in more than 65% of the non-empty sampled stomachs evidenced the cannibalism of D. gigas. The results improved current understanding of the fishery biology of D. gigas off the Costa Rica Dome, which may facilitate the assessment and management of relative fishery resources.

  15. Squid Giant Axon Contains Neurofilament Protein mRNA but does not Synthesize Neurofilament Proteins.

    Science.gov (United States)

    Gainer, Harold; House, Shirley; Kim, Dong Sun; Chin, Hemin; Pant, Harish C

    2017-04-01

    When isolated squid giant axons are incubated in radioactive amino acids, abundant newly synthesized proteins are found in the axoplasm. These proteins are translated in the adaxonal Schwann cells and subsequently transferred into the giant axon. The question as to whether any de novo protein synthesis occurs in the giant axon itself is difficult to resolve because the small contribution of the proteins possibly synthesized intra-axonally is not easily distinguished from the large amounts of the proteins being supplied from the Schwann cells. In this paper, we reexamine this issue by studying the synthesis of endogenous neurofilament (NF) proteins in the axon. Our laboratory previously showed that NF mRNA and protein are present in the squid giant axon, but not in the surrounding adaxonal glia. Therefore, if the isolated squid axon could be shown to contain newly synthesized NF protein de novo, it could not arise from the adaxonal glia. The results of experiments in this paper show that abundant 3H-labeled NF protein is synthesized in the squid giant fiber lobe containing the giant axon's neuronal cell bodies, but despite the presence of NF mRNA in the giant axon no labeled NF protein is detected in the giant axon. This lends support to the glia-axon protein transfer hypothesis which posits that the squid giant axon obtains newly synthesized protein by Schwann cell transfer and not through intra-axonal protein synthesis, and further suggests that the NF mRNA in the axon is in a translationally repressed state.

  16. NanoSQUID magnetometry of individual cobalt nanoparticles grown by focused electron beam induced deposition

    Science.gov (United States)

    Martínez-Pérez, M. J.; Müller, B.; Schwebius, D.; Korinski, D.; Kleiner, R.; Sesé, J.; Koelle, D.

    2017-02-01

    We demonstrate the operation of low-noise nano superconducting quantum interference devices (SQUIDs) based on the high critical field and high critical temperature superconductor YBa2Cu3O7 (YBCO) as ultra-sensitive magnetometers for single magnetic nanoparticles (MNPs). The nanoSQUIDs exploit the Josephson behavior of YBCO grain boundaries and have been patterned by focused ion beam milling. This allows us to precisely define the lateral dimensions of the SQUIDs so as to achieve large magnetic coupling between the nanoloop and individual MNPs. By means of focused electron beam induced deposition, cobalt MNPs with a typical size of several tens of nm have been grown directly on the surface of the sensors with nanometric spatial resolution. Remarkably, the nanoSQUIDs are operative over extremely broad ranges of applied magnetic field (-1 T \\lt {μ }0H\\lt 1 T) and temperature (0.3 K \\lt T\\lt 80 K). All these features together have allowed us to perform magnetization measurements under different ambient conditions and to detect the magnetization reversal of individual Co MNPs with magnetic moments (1-30) × {10}6 {μ }{{B}}. Depending on the dimensions and shape of the particles we have distinguished between two different magnetic states yielding different reversal mechanisms. The magnetization reversal is thermally activated over an energy barrier, which has been quantified for the (quasi) single-domain particles. Our measurements serve to show not only the high sensitivity achievable with YBCO nanoSQUIDs, but also demonstrate that these sensors are exceptional magnetometers for the investigation of the properties of individual nanomagnets.

  17. Transcriptome analysis of Nautilus and pygmy squid developing eye provides insights in lens and eye evolution.

    Science.gov (United States)

    Sousounis, Konstantinos; Ogura, Atsushi; Tsonis, Panagiotis A

    2013-01-01

    Coleoid cephalopods like squids have a camera-type eye similar to vertebrates. On the other hand, Nautilus (Nautiloids) has a pinhole eye that lacks lens and cornea. Since pygmy squid and Nautilus are closely related species they are excellent model organisms to study eye evolution. Having being able to collect Nautilus embryos, we employed next-generation RNA sequencing using Nautilus and pygmy squid developing eyes. Their transcriptomes were compared and analyzed. Enrichment analysis of Gene Ontology revealed that contigs related to nucleic acid binding were largely up-regulated in squid, while the ones related to metabolic processes and extracellular matrix-related genes were up-regulated in Nautilus. These differences are most likely correlated with the complexity of tissue organization in these species. Moreover, when the analysis focused on the eye-related contigs several interesting patterns emerged. First, contigs from both species related to eye tissue differentiation and morphogenesis as well as to cilia showed best hits with their Human counterparts, while contigs related to rabdomeric photoreceptors showed the best hit with their Drosophila counterparts. This bolsters the idea that eye morphogenesis genes have been generally conserved in evolution, and compliments other studies showing that genes involved in photoreceptor differentiation clearly follow the diversification of invertebrate (rabdomeric) and vertebrate (ciliated) photoreceptors. Interestingly some contigs showed as good a hit with Drosophila and Human homologues in Nautilus and squid samples. One of them, capt/CAP1, is known to be preferentially expressed in Drosophila developing eye and in vertebrate lens. Importantly our analysis also provided evidence of gene duplication and diversification of their function in both species. One of these genes is the Neurofibromatosis 1 (NF1/Nf1), which in mice has been implicated in lens formation, suggesting a hitherto unsuspected role in the evolution

  18. Preparation and characterisation of irradiated crab chitosan and New Zealand Arrow squid pen chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Shavandi, Amin, E-mail: amin.shavandi@postgrad.otago.ac.nz [Department of Food Sciences, University of Otago, Dunedin (New Zealand); Bekhit, Adnan A. [Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Alexandria, Alexandria (Egypt); Bekhit, Alaa El-Din A. [Department of Food Sciences, University of Otago, Dunedin (New Zealand); Sun, Zhifa [Department of Physics, University of Otago, Dunedin (New Zealand); Ali, M. Azam [Department of Applied Sciences, University of Otago, Dunedin (New Zealand)

    2015-11-01

    The properties of chitosan from Arrow squid (Nototodarus sloanii) pen (CHS) and commercial crab shell (CHC) were investigated using FTIR, DSC, SEM and XRD before and after irradiation at the dose of 28 kGy in the presence or absence of 5% water. Also, the viscosity, deacetylation degree, water and oil holding capacities, colour and antimicrobial activities of the chitosan samples were determined. Irradiation decreased (P < 0.05) the viscosity of CHC from 0.21 to 0.03 Pa s and of CHS from 1.71 to 0.23 Pa s. The inclusion of water had no effect on the viscosity of irradiated chitosan. Irradiation did not affect the degree of deacetylation of CHC, but increased the deacetylation degree of CHS from 72.78 to 82.29% in samples with 5% water. Water and oil holding capacities of CHS (1197.30% and 873.3%, respectively) were higher (P < 0.05) than those found in CHC (340.70% and 264.40%, respectively). The water and oil holding capacities were decreased for both types of chitosan irradiation, but were not affected by the addition of water. Squid pen chitosan was whiter in colour (White Index = 90.06%) compared to CHC (White Index = 83.70%). Generally, the CHC samples (control and irradiated) exhibited better antibacterial activity compared to CHS, but the opposite was observed with antifungal activity. - Highlights: • Chitosan prepared from Arrow squid pens (Nototodarus sloanii). • Chitosan samples were gamma irradiated at 28 kGy. • Squid pen chitosan showed high fat and water uptake capacities compared to crab shell chitosan. • Gamma irradiation enhanced the DDA of squid pen chitosan but not crab shell chitosan.

  19. Tropic dynamics of albatrosses associated with squid and large-mesh driftnet fisheries in the North Pacific Ocean

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Diets of Laysan (LAA) and Black-footed albatrosses (BFA) killed in squid and large-mesh driftnets in the transitional zone of the North Pacific Ocean were...

  20. Low-frequency noise in high-{Tc} superconductor Josephson junctions, SQUIDs, and magnetometers

    Energy Technology Data Exchange (ETDEWEB)

    Miklich, A.H.

    1994-05-01

    Design and performance of high-T{sub c} dc superconducting quantum interference devices (SQUEDs), junctions that comprise them, and magnetometers made from them are described, with attention to sources of 1/f noise. Biepitaxial junctions are found to have large levels of critical current fluctuations which make them unsuitable for low-noise SQUIDS; this suggests a poorly connected interface at the grain boundary junction. SQUIDs from bicrystal junctions have levels of critical current noise controllable using bias current reversal techniques which leave the noise white down to frequencies of a few Hz. A SQUID with an energy resolution of 1.5{times}10{sup {minus}30} J Hz{sup {minus}1} at 1 Hz is reported. Magnetometers in which a (9 mm){sup 2} pickup loop is directly coupled to a SQUID body have achieved field resolutions of 93 fT Hz{sup {minus}1/2} down to frequencies below I Hz, improving to 39 fT Hz{sup {minus}1/2} at 1 Hz with the addition of a 50mm-diameter single-turn flux transformer. Poor coupling to pickup loop makes it difficult to satisfy competing goals of high field resolution and small detector size necessary for multichannel biomagnetic imaging. Improved coupling is demonstrated by the use of multiturn-input-coil flux transformers, and a resolution of 35 fT Hz{sup {minus}1/2} in the white noise region is reported with a (10 mm){sup 2} pickup loop. However, additional 1/f noise from processed multilayer structures in the transformer limits the resolution at 1 Hz to 114 fT Hz{sup {minus}1/2}. High-T{sub c} SQUIDs exhibit additional 1/f noise when cooled in a nonzero static magnetic field because of additional flux vortices trapped in the film, with the noise power at 1 Hz typically increasing by a factor of 10--20 in a field of 0.05mT (0.5 G). Finally, a SQUID-based voltmeter with a resolution of 9.2 pV.Hz{sup {minus}1/2} at 10 Hz (24 pV Hz{sup {minus}1/2} at 1 Hz) is described.

  1. Dc SQUIDs with sub-micron-sized Nb/HfTi/Nb Josephson junctions for operation in high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Nagel, Joachim; Konovalenko, Konstantin; Kleiner, Reinhold; Koelle, Dieter [Physikalisches Institut - Experimentalphysik II, Center for Collective Quantum Phenomena and their Applications, Universitaet Tuebingen, Auf der Morgenstelle 14, D-72076 (Germany); Kieler, Oliver; Kohlmann, Johannes; Zorin, Alexander [Fachbereich 2.4 ' ' Quantenelektronik' ' , Physikalisch-Technische Bundesanstalt, 38116 Braunschweig (Germany)

    2010-07-01

    We investigate the suitability of dc superconducting quantum interference devices (SQUIDs) for operation in high magnetic fields (up to B{approx}100 mT) at temperature T=4.2 K. The micro SQUIDs with superconductor (S)-normal metal (N)-superconductor (S) sub-micrometer Josephson junctions were realized using Nb electrodes and HfTi for the normal interlayer. Our fabrication technology combines e-beam lithography and chemical-mechanical polishing which enables junction sizes down to 200 nm x 200 nm, integrated into small superconductor rings with inner dimensions down to 0.5 {mu} m x 0.5 {mu} m. The characteristic voltage of the SNS junctions is typically 30-40 {mu}V with a McCumber parameter {beta}{sub C}<0.1, and a screening parameter of the SQUIDs {beta}{sub L}{approx}0.2. The SQUIDs where characterized by measurements of electric transport and noise (using a Nb dc SQUID amplifier) in a magnetically shielded environment as well as in high magnetic fields. The SQUIDs show very low flux noise which is a major prerequisite for their application as detectors for magnetic properties of nanoparticles.

  2. Eleven Novel Polymorphic Microsatellite Loci for Oval Squid Sepioteuthis Lessoniana (Shiro-Ika Type)

    Science.gov (United States)

    Tomano, Satoshi; Ahmad-Syazni, Kamarudin; Ueta, Yukio; Ohara, Kenichi; Umino, Tetsuya

    2013-01-01

    The oval squid Sepioteuthis lessoniana is one of the most economically important squid species in Japan; however, its population structure is poorly understood due to the lack of hypervariable markers. Such information is critical for managing sustainable fisheries, as well as for ensuring the existence of wild S. lessoniana stocks. Eleven candidate microsatellite loci were isolated from a small insert genomic DNA library. Polymorphisms in these 11 loci were screened in 24 wild individuals. The number of alleles per locus was found to range from 5 to 19 alleles, and the observed heterozygosity ranged from 0.292 to 0.958. No evidence for linkage disequilibrium was detected among all the loci. The genotypic proportions conformed to Hardy-Weinberg equilibrium, except at one locus. In conclusion, these polymorphic microsatellite loci may be used to develop a genetic framework to manage S. lessoniana in the future. PMID:24108369

  3. Multi-Channel Magnetocardiogardiography System Based on Low-Tc SQUIDs in an Unshielded Environment

    Science.gov (United States)

    Kong, Xiangyan; Zhang, Shulin; Wang, Yongliang; Zeng, Jia; Xie, Xiaoming

    Magnetocardiography (MCG) using superconducting quantum interference devices (SQUIDs) is a new medical diagnostic tool measuring biomagnetic signals that are generated by the electrical activity of the human heart. This technique is completely passive, contactless, and it has an advantage in the early diagnosis of heart diseases. We developed the first unshielded four-channel MCG system based on low-Tc DC SQUIDs in China. Instead of using a costly magnetically shielded room, the environmental noise suppression was realized by using second-order gradiometers and three-axis reference magnetometer. The measured magnetic field resolution of the system is better than 1 pT, and multi-cycle human heart signals can be recorded directly. Also, with the infrared positioning system, 48 points data collection can be realized by moving the non-magnetic bed nine times.

  4. Chemical and Functional Characterization of Sarcoplasmic Proteins from Giant Squid (Dosidicus gigas Mantle

    Directory of Open Access Journals (Sweden)

    Rosa Linda Lopez-Enriquez

    2015-01-01

    Full Text Available Modification of pH and NaCl concentration changed the physicochemical properties of sarcoplasmic proteins (SP from jumbo squid mantle and consequently their functional properties. Better results of emulsifying activity index (EAI and foam capacity (FC were exhibited at pH 11 in NaCl absence due to higher solubility. But better emulsifying stability index (ESI was obtained at pH 11 in 0.5 M NaCl, while, foaming stability (FS was better at pH near to isoelectric point (pI. These results suggest that SP from jumbo squid may be a promising ingredient, whose functional properties can be manipulated by changing pH and NaCl concentration.

  5. Detection of low cycle fatigue in type 316 stainless steel using HTS-squid

    Energy Technology Data Exchange (ETDEWEB)

    Park, D.G.; Kim, D.W.; Hong, J.H. [Korea Atomic Energy Research Inst., Daejeon (Korea); Timofeev, V.P. [Verkin Inst. for Low Temperature Physics and Eng, Kharkov (Ukraine)

    2004-07-01

    A portable RF HTS squid-based susceptometer was applied to the measurement of fatigue behavior for type 316L(N) stainless steel containing 0.04% to 0.15% nitrogen content. Strain-controlled low cycle fatigue (LCF) tests were conducted at RT and 600 C in air an atmosphere, and the magnetic moments were measured after the fatigue test using HTS SQUID. The magnetic moment of an as-received sample is higher than that of a fatigued sample in all the temperature ranges irrespective of the nitrogen content. The fatigue life decreased with an increasing test temperature up to 500 C, but increased at 600 C. The change of magnetic moments by LCF test is attributed to the stress induced micro defects. (orig.)

  6. Improved noise performance of ultrathin YBCO Dayem bridge nanoSQUIDs

    Science.gov (United States)

    Arpaia, R.; Arzeo, M.; Baghdadi, R.; Trabaldo, E.; Lombardi, F.; Bauch, T.

    2017-01-01

    We have fabricated YBa2Cu3O{}7-δ (YBCO) nano superconducting quantum interference devices (nanoSQUIDs), realized in Dayem bridge configuration, on films with thickness down to 10 nm. The devices, which have not been protected by a Au capping layer during the nanopatterning, show modulations of the critical current as a function of the externally applied magnetic field from 300 mK up to the critical temperature of the nanobridges. The absence of the Au shunting layer and the enhancement of the sheet resistance in ultrathin films lead to very large voltage modulations and transfer functions, which make these nanoSQUIDs highly sensitive devices. Indeed, by using bare YBCO nanostructures, we have revealed an upper limit for the intrinsic white flux noise level {S}{{Φ },{{w}}}1/2\\lt 450 {{n}}{{{Φ }}}0 {{Hz}}-1/2.

  7. Sensory acceptability of squid rings gamma irradiated for shelf-life extension

    Science.gov (United States)

    Tomac, Alejandra; Cova, María C.; Narvaiz, Patricia; Yeannes, María I.

    2017-01-01

    The feasibility of extending the shelf-life of a squid product by gamma irradiation was analyzed. Illex argentinus rings were irradiated at 4 and 8 kGy; and stored at 4±1 °C during 77 days. No mesophilic bacteria, enterobacteriaceae and coliforms were detected in irradiated rings during storage. Psychrotrophic bacteria were significantly reduced by irradiation; their counts were fitted to a growth model which was further used for shelf-life estimations: 3 and 27 days for 0 and 4 kGy, respectively. Initially, non-irradiated as well as irradiated rings had very good sensory scores. The overall acceptability of 4 and 8 kGy rings did not decrease during 27 and 64 days, respectively, while control samples spoiled after 3 days. A radiation dose range for squid rings preservation was defined, which attained the technological shelf-life extension objective, without impairing sensory quality.

  8. Measurement of the signal from a cultured cell using a high-T{sub c} SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Saburo; Tanaka, Nobuaki; Natsume, Miyuki; Uchida, Masashi; Oshita, Miyuki; Aspanut, Zarina; Eki, Toshihiko; Yoshida, Sachiko [Toyohashi University of Technology, Hibarigaoka Tempaku-cho Toyohashi Aichi, 441-8580 (Japan)

    2003-12-01

    Stem cells in developing tissues give rise to the multiple specialized cell types that make up the heart, lung, skin, and other tissues. For scientists, it is important to know the stages of stem cell development. We propose a new method to obtain knowledge of the cell development stages by using a high-T{sub c} SQUID magnetometer. In the first step of the research, we used Wister rat myocardial cells incubated for 12-14 days in a culture dish as a sample, which were not derived from stem cells. With the cells we tried to measure the signal using a SQUID magnetometer. We were able to measure the magnetic signals, which may be generated by ion transport through the cell membrane. A beat signal with a period of 0.6 s was observed. The peak-to-peak value was about 400 pT. This showed good agreement with the result of microscopic observation.

  9. Development of high-T{sub c} SQUID microscope with flux guide

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Saburo; Matsuda, Kazuka; Yamazaki, Osamu; Natsume, Miyuki; Ota, Hajime; Mizoguchi, Takahiro [Department of Ecological Engineering, Toyohashi University of Technology, Hibarigaoka, Tempaku-cho, Toyohashi Aichi (Japan)

    2002-01-01

    We have developed a new type of superconducting interference device (SQUID) microscope. A direct-coupled SQUID magnetometer with a high-{mu} metal needle was used and the substrate was machined to create a dimple for the needle at the centre of the pick-up loop. One end of the needle penetrated through the superconducting pick-up loop in a vacuum; the needle was fixed in the vacuum window with the other end at room temperature in the outside atmosphere. Several kinds of simulation using a Maxwell simulator were performed and the results were applied to our system. As a demonstration, a laser-printed output was scanned by the microscope. Line bars with a line width of 100 {mu}m and a spacing between lines of 200 {mu}m were clearly imaged. (author)

  10. Measurement of metallic contaminants in food with a high-T{sub c} SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Saburo; Natsume, Miyuki; Uchida, Masashi; Hotta, Naoki; Matsuda, Takemasa; Spanut, Zarina A; Hatsukade, Yoshimi [Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi Aichi 441-8580 (Japan)

    2004-04-01

    We have proposed and demonstrated a high-T{sub c} SQUID system for detecting metallic contaminants in foodstuffs. There is a demand for the development of systems for detecting not only magnetic materials but also non-magnetic materials such as Cu and aluminium in foodstuffs to ensure food safety. The system consists of a SQUID magnetometer, an excitation coil and a permanent magnet. For a non-magnetic sample, an AC magnetic field is applied during detection to induce an eddy current in the sample. For a magnetizable sample, a strong magnetic field is applied to the sample prior to the detection attempt. We were able to detect a stainless steel ball with a diameter of 0.1 mm and a Cu ball less than 1 mm in diameter, for example.

  11. All-planar SQUIDs and pickup coils for combined MEG and MRI

    Energy Technology Data Exchange (ETDEWEB)

    Luomahaara, J; Kiviranta, M; Groenberg, L; Hassel, J [VTT Technical Research Centre of Finland, PO BOX 1000, 02044 VTT (Finland); Vesanen, P T; Nieminen, J O; Dabek, J; Zevenhoven, C J; Ilmoniemi, R J [Department of Biomedical Engineering and Computational Science, Aalto University, PO BOX 12200, 00076 Aalto (Finland); Penttilae, J [Aivon Oy, Tietotie 3, 02150 Espoo (Finland); Simola, J, E-mail: juho.luomahaara@vtt.fi [Elekta Oy, PO Box 34, 00531 Helsinki (Finland)

    2011-07-15

    Flux trapping and random flux movement are common problems in superconducting thin-film devices. Ultrasensitive magnetic field sensors based on superconducting quantum interference devices (SQUIDs) coupled to large pickup coils are especially vulnerable to strong external fields. The issue has become particularly relevant with the introduction of SQUID-based ultra-low-field (ULF) nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) techniques. In this paper, we study the constraints of thin-film-based magnetometers and gradiometers as exposed to magnetic field sequences of ULF MRI. In particular, we address issues such as response recovery, transient noise, magnetization and behaviour under shielded room conditions after prepolarization. As a result, we demonstrate sensors that are suitable for a combined multi-channel magnetoencephalography (MEG) and MRI imaging system.

  12. "Squid-capture" modified in situ stent-graft fenestration technique for aortic arch aneurysm repair.

    Science.gov (United States)

    Hongo, Norio; Miyamoto, Shinji; Shuto, Rieko; Wada, Tomoyuki; Kamei, Noritaka; Sato, Aiko; Matsumoto, Shunro; Kiyosue, Hiro; Mori, Hiromu

    2014-08-01

    An 83-year-old female was found to have an fusiform aneurysm in the aortic arch. She was deemed to be a high surgical risk; therefore, endovascular stent-graft placement followed by revascularization of the brachiocephalic trunk using in situ stent-graft fenestration was considered. However, the safe application of fenestration was deemed difficult due to the tortuosity of the brachiocephalic artery. The patient was successfully treated with the aid of the "squid-capture" technique, which consists of deployment of the stent-graft in a snare wire loop that was advanced from the brachiocephalic artery and fenestration of the stent-graft with the support of the loop. A follow-up exam revealed complete sealing of the aneurysm without any complications. The squid-capture technique allows for the safe and secure puncture of the graft.

  13. SQUID magnetometry for the cryoEDM experiment-Tests at LSBB

    Energy Technology Data Exchange (ETDEWEB)

    Henry, S; Kraus, H; Malek, M; Mikhailik, V B [University of Oxford, Department of Physics, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Waysand, G [Laboratoire Souterrain a Bas Bruit de Rustrel-Pays d' Apt (LSBB), Universite de Nice Sophia-Antipolis, La Grande Combe, 84400 Rustrel (France)], E-mail: s.henry1@physics.ox.ac.uk

    2008-11-15

    High precision magnetometry is an essential requirement of the cryoEDM experiment at the Institut Laue-Langevin, Grenoble. We have developed a SQUID system for this purpose, however tests done in Oxford have been limited by the noisy electromagnetic environment inside our laboratory, therefore we have tested a smaller version of our prototype system in the very low noise environment at LSBB, Rustrel, France. We have studied the crosstalk between an array of parallel pick-up loops-where the field generated by a current in one loop is detected by the others. We monitored the magnetic field in the LSBB for over twelve hours; and after correcting these data for SQUID resets, and crosstalk, we compare it to the published values from nearby geomagnetic observatories. We have also measured the noise spectrum of our system and studied the effect that heating one of the pick-up loops into its conducting state has on the other, parallel loops.

  14. Artificial neural network based on SQUIDs: demonstration of network training and operation

    Science.gov (United States)

    Chiarello, F.; Carelli, P.; Castellano, M. G.; Torrioli, G.

    2013-12-01

    We propose a scheme for the realization of artificial neural networks based on superconducting quantum interference devices (SQUIDs). In order to demonstrate the operation of this scheme we designed and successfully tested a small network that implements an XOR gate and is trained by means of examples. The proposed scheme can be particularly convenient as support for superconducting applications such as detectors for astrophysics, high energy experiments, medicine imaging and so on.

  15. JOSEPHSON EFFECTS IN CERAMIC SUPERCONDUCTORS AND THEIR APPLICATION TO SQUID MAGNETOMETRY

    OpenAIRE

    Gough, C.

    1988-01-01

    A brief review is given of Josephson Effects in high-Tc superconductors with specific reference to ceramic material properties and device applications. The development of liquid-nitrogen cooled rf and dc SQUIDs for ultrasensitive magnetometry will be described. Field sensitivities of better than 10-12 T / √Hz have already been achieved but 1 / f -noise becomes important at low frequencies.

  16. Preparation of squid skin collagen hydrolysate as an antihyaluronidase, antityrosinase, and antioxidant agent.

    Science.gov (United States)

    Nakchum, Ladawan; Kim, Sang Moo

    2016-01-01

    A collagen was isolated from squid skin, a processing waste product. The biofunctional activities of enzymatic squid skin collagen hydrolysates were determined to produce a value-added material. Five low-molecular-mass hydrolysate fractions, F1 (>30 kD), F2 (10-30 kD), F3 (3-10 kD), F4 (1-3 kD), and F5 (<1 kD), were manufactured from its enzymatic hydrolysate by ultrafiltration. Fraction F3 had the strongest antihyaluronidase inhibitory activity. Gly, Val, and Pro were major amino acids in F3, while Met, Tyr, and His were minor ones. The molecular mass of F3 was in the range of 3.4 to 10 kD. F3 exhibited copper chelating ability in a concentration-dependent manner. The ferrous chelating ability of F3 was almost 50% at 200 µg/mL. F3 also inhibited tyrosinase activity by 39.65% at 1 mg/mL. Furthermore, F3 had stronger hydroxyl radical scavenging activity (IC50 = 149.94 µg/mL) than ascorbic acid (IC50 = 212.94 µg/mL). Therefore, the squid collagen hydrolysate can be utilized as a nutraceutical or cosmeceutical agent.

  17. Hypoxia tolerance and antioxidant defense system of juvenile jumbo squids in oxygen minimum zones

    Science.gov (United States)

    Trübenbach, Katja; Teixeira, Tatiana; Diniz, Mário; Rosa, Rui

    2013-10-01

    Jumbo squid (Dosidicus gigas) is a large oceanic squid endemic off the Eastern Tropical Pacific that undertakes diel vertical migrations into mesopelagic oxygen minimum zones. One of the expected physiological effects of such migration is the generation of reactive oxygen species (ROS) at the surface, promoted by the transition between hypoxia and reoxygenation states. The aim of this study was to investigate the energy expenditure rates and the antioxidant stress strategies of juvenile D. gigas under normoxia and hypoxia, namely by quantifying oxygen consumption rates, antioxidant enzyme activities [including superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST)], heat shock protein expression (Hsp70/Hsc70), and lipid peroxidation [malondialdehyde (MDA) levels]. A high significant decrease (68%) in squid's metabolic rates was observed during hypoxia (p0.05), with the latter indicating no enhancement of lipid peroxidation (i.e. cellular damage) at the warmer and normoxic surface waters. The understanding of such physiological strategies that are linked to oxygen deprivation and reoxygenation phases may provide valuable information about how this species is quickly responding to the impacts of environmental stressors coupled with global climate change.

  18. Onshore-offshore movement of jumbo squid (Dosidicus gigas) on the continental shelf

    Science.gov (United States)

    Stewart, Julia S.; Gilly, William F.; Field, John C.; Payne, John C.

    2013-10-01

    Jumbo squid (Dosidicus gigas) have greatly extended their range in the California Current System, where they forage on a variety of ecologically and economically important species that inhabit both coastal and offshore mesopelagic regions. Swimming abilities and behavior are important factors in assessing the impacts of this range expansion, particularly in regard to foraging in conjunction with onshore-offshore movement over the continental shelf. Here we describe a study of horizontal movements by jumbo squid along and across the continental shelf off Washington, USA, using acoustic tags in association with the Census of Marine Life's Pacific Ocean Shelf Tracking Program (POST) receiver arrays. We detected frequent movements along the shelf break, movement onto the shelf at night, and no evidence of movement as a cohesive school. Our results demonstrate feasibility of using acoustic tags and arrays to document horizontal movements of jumbo squid along and across the continental shelf. This is important in order to determine how those movements overlap with those of other ecologically and commercially important fish species.

  19. Trace element concentrations in the top predator jumbo squid (Dosidicus gigas) from the Gulf of California.

    Science.gov (United States)

    Raimundo, Joana; Vale, Carlos; Rosa, Rui

    2014-04-01

    Jumbo (or Humboldt) squid, Dosidicus gigas, is a large jet-propelled top oceanic predator off the Eastern Pacific. The present study reports, for the first time, concentrations of V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Cd and Pb in gills, mantle and digestive gland of this powerful pelagic squid in the Gulf of California. Zinc and Cu were the most abundant elements. All elements, with the exception of As, were largely stored in digestive gland; particularly Cd that reached concentrations between 57 and 509 µg g(-1). Significant relationships between tissues were found for Co (digestive gland-gills), As (gills-mantle) and Cd (digestive gland-mantle). Proportionality of Cd concentrations between mantle and digestive gland suggested that detoxification capacity by digestive gland was insufficient to avoid the transfer of this element to mantle and other tissues. Nonetheless, Cd concentrations in the mantle were always below the regulatory limit and, therefore lack of constraints for human consumption. On the basis of the fishery landings, one may estimate that up to 1t of Cd can be annually removed by jumbo squid fisheries.

  20. Revealing the potential of squid chitosan-based structures for biomedical applications.

    Science.gov (United States)

    Reys, L L; Silva, S S; Oliveira, J M; Caridade, S G; Mano, J F; Silva, T H; Reis, R L

    2013-08-01

    In recent years, much attention has been given to different marine organisms, namely as potential sources of valuable materials with a vast range of properties and characteristics. In this work, β-chitin was isolated from the endoskeleton of the giant squid Dosidicus gigas and further deacetylated to produce chitosan. Then, the squid chitosan was processed into membranes and scaffolds using solvent casting and freeze-drying, respectively, to assess their potential biomedical application. The developed membranes have shown to be stiffer and less hydrophobic than those obtained with commercial chitosan. On the other hand, the morphological characterization of the developed scaffolds, by SEM and micro-computed tomography, revealed that the matrices were formed with a lamellar structure. The findings also indicated that the treatment with ethanol prior to neutralization with sodium hydroxide caused the formation of larger pores and loss of some lamellar features. The in vitro cell culture study has shown that all chitosan scaffolds exhibited a non-cytotoxic effect over the mouse fibroblast-like cell line, L929 cells. Thus, chitosan produced from the endoskeletons of the giant squid Dosidicus gigas has proven to be a valuable alternative to existing commercial materials when considering its use as biomaterial.

  1. SQUID Based Cryogenic Current Comparator for Measurements of the Dark Current of Superconducting Cavities

    CERN Document Server

    Vodel, W; Neubert, R; Nietzsche, S

    2005-01-01

    This contribution presents a LTS-SQUID based Cryogenic Current Comparator (CCC) for detecting dark currents, generated e.g. by superconducting cavities for the upcoming X-FEL project at DESY. To achieve the maximum possible energy the gradients of the superconducting RF cavities should be pushed close to the physical limit of 50 MV/m. The measurement of the undesired field emission of electrons (the so-called dark current) in correlation with the gradient will give a proper value to compare and classify the cavities. The main component of the CCC is a high performance LTS-DC SQUID system which is able to measure extremely low magnetic fields, e.g. caused by the extracted dark current. For this reason the input coil of the SQUID is connected across a special designed toroidal niobium pick-up coil (inner diameter: about 100 mm) for the passing electron beam. A noise limited current resolution of nearly 2 pA/√(Hz) with a measurement bandwidth of up to 70 kHz was achieved without the pick-up coil. Now, ...

  2. Utilization of squid pen for the efficient production of chitosanase and antioxidants through prolonged autoclave treatment.

    Science.gov (United States)

    Wang, San-Lang; Wu, Pei-Chen; Liang, Tzu-Wen

    2009-05-26

    We have developed a culture system for efficient production of chitosanase by Bacillus sp. TKU004. TKU004 was cultivated by using squid pen powder as the sole carbon/nitrogen source. The effects of autoclave treatments of the medium on the production of chitosanase were investigated. Autoclave treatment of squid pen powder for 45 min remarkably promoted enzyme productivity. When the culture medium containing an initial squid pen powder concentration of 3% was autoclaved for 45 min, the chitosanase activity was optimal and reached 0.14-0.16 U/mL. In addition, extracellular surfactant-stable chitosanase was purified from the TKU004 culture supernatant. The antioxidant activity of TKU004 culture supernatant was determined through the scavenging ability of DPPH, with 70% per mL. With this method, we have shown that marine wastes can be utilized efficiently through prolonged autoclave treatments to generate a high value-added product, and have revealed its hidden potential in the production of functional foods.

  3. Reproductive behavior in the squid Sepioteuthis australis from South Australia: ethogram of reproductive body patterns.

    Science.gov (United States)

    Jantzen, Troy M; Havenhand, Jon N

    2003-06-01

    Squids use a diverse range of body patterns for communication. Each pattern consists of a series of chromatic, postural, and locomotor components that are under neural control and can change within fractions of a second. Here we describe an ethogram of 48 body pattern components from in situ observations of reproductively active Sepioteuthis australis. In addition, we identify the total time and average duration that each component is shown, to a resolution of 1 s. Our results suggest that only a few components (e.g., "Golden epaulettes," "Stitchwork fins," and "Rigid arms") are temporally common, that is, shown for more than 80% of the time. In contrast to the component classification reported for other species of squid, for this species we suggest a classification system consisting of "short acute" (lasting for 60 s). Several body patterning components were previously unreported, as were some of the combinations observed. The significance of these patterning components is discussed within the context of the associated behaviors of the squid on the spawning grounds.

  4. Structure-based modelling of hemocyanin allergenicity in squid and its response to high hydrostatic pressure

    Science.gov (United States)

    Zhang, Yifeng; Deng, Yun; Zhao, Yanyun

    2017-01-01

    The secondary, tertiary, and quaternary structures of squid hemocyanin (Hc) were characterised, and the relationship between Hc structure and allergenicity responses to high hydrostatic pressure (HHP) was modelled. The Hc allergenicity varied with its protein structure. Electrophoresis analysis revealed that HHP treatment significantly decreased the band intensity of Hc when increasing pressure from 200 and 400 MPa to 600 MPa. The protein structure analysis of squid Hc showed that while HHP treatment decreased the α-helix content, free sulfhydryl content, and Rg, it increased the random coil content, surface hydrophobicity index (Ho), Guinier aggregation number (〈Nagg〉G) and average aggregation number (〈Nagg〉Q). The α-helix and random coil contents of the 600 MPa treated samples were 23.67% and 37.54%, respectively, compared to 32.37% and 32.02% in the control, respectively. HHP treatment decreased the IgE and IgG-binding capacities, indicating a significant decrease in the allergenicity (Pallergenicity, and explained the responses of Hc protein structure to HHP for lowering the allergenicity of squid. PMID:28112159

  5. Chitinolytic Bacteria-Assisted Conversion of Squid Pen and Its Effect on Dyes and Pigments Adsorption.

    Science.gov (United States)

    Liang, Tzu-Wen; Lo, Bo-Chang; Wang, San-Lang

    2015-07-23

    The aim of this work was to produce chitosanase by fermenting from squid pen, and recover the fermented squid pen for dye removal by adsorption. One chitosanase induced from squid pen powder (SPP)-containing medium by Bacillus cereus TKU034 was purified in high purification fold (441) and high yield of activity recovery (51%) by ammonium sulfate precipitation and combined column chromatography. The SDS-PAGE results showed its molecular mass to be around 43 kDa. The TKU034 chitosanase used for the chitooligomers preparation was studied. The enzyme products revealed that the chitosanase could degrade chitosan with various degrees of polymerization, ranging from 3 to 9, as well as the chitosanase in an endolytic manner. Besides, the fermented SPP was recovered and displayed a better adsorption rate (up to 99.5%) for the disperse dyes (red, yellow, blue, and black) than the water-soluble food colorants, Allura Red AC (R40) and Tartrazine (Y4). The adsorbed R40 on the unfermented SPP and the fermented SPP was eluted by distilled water and 1 M NaOH to confirm the dye adsorption mechanism. The fermented SPP had a slightly higher adsorption capacity than the unfermented, and elution of the dye from the fermented SPP was easier than from the unfermented. The main dye adsorption mechanism of fermented SPP was physical adsorption, while the adsorption mechanism of unfermented SPP was chemical adsorption.

  6. Ultraviolet Laser SQUID Microscope for GaN Blue Light Emitting Diode Testing

    Energy Technology Data Exchange (ETDEWEB)

    Daibo, M [Department of Electrical and Electronic Engineering, Faculty of Engineering, Iwate University, Morioka 020-8551 (Japan); Kamiwano, D [Graduate School of Engineering, Iwate University, Morioka 020-8551 (Japan); Kurosawa, T [Graduate School of Engineering, Iwate University, Morioka 020-8551 (Japan); Yoshizawa, M [Graduate School of Engineering, Iwate University, Morioka 020-8551 (Japan); Tayama, N [Department of Electrical and Electronic Engineering, Faculty of Engineering, Iwate University, Morioka 020-8551 (Japan)

    2006-06-01

    We carried out non-contacting measurements of photocurrent distributions in GaN blue light emitting diode (LED) chips using our newly developed ultraviolet (UV) laser SQUID microscope. The UV light generates the photocurrent, and then the photocurrent induces small magnetic fields around the chip. An off-axis arranged HTS-SQUID magnetometer is employed to detect a vector magnetic field whose typical amplitude is several hundred femto-tesla. Generally, it is difficult to obtain Ohmic contacts for p-type GaN because of the low hole concentration in the p-type epitaxial layer and the lack of any available metal with a higher work function compared with the p-type GaN. Therefore, a traditional probecontacted electrical test is difficult to conduct for wide band gap semiconductors without an adequately annealed electrode. Using the UV-laser SQUID microscope, the photocurrent can be measured without any electrical contact. We show the photocurrent vector map which was reconstructed from measured magnetic fields data. We also demonstrate how we found the position of a defect of the electrical short circuits in the LED chip.

  7. Chitinolytic Bacteria-Assisted Conversion of Squid Pen and Its Effect on Dyes and Pigments Adsorption

    Directory of Open Access Journals (Sweden)

    Tzu-Wen Liang

    2015-07-01

    Full Text Available The aim of this work was to produce chitosanase by fermenting from squid pen, and recover the fermented squid pen for dye removal by adsorption. One chitosanase induced from squid pen powder (SPP-containing medium by Bacillus cereus TKU034 was purified in high purification fold (441 and high yield of activity recovery (51% by ammonium sulfate precipitation and combined column chromatography. The SDS-PAGE results showed its molecular mass to be around 43 kDa. The TKU034 chitosanase used for the chitooligomers preparation was studied. The enzyme products revealed that the chitosanase could degrade chitosan with various degrees of polymerization, ranging from 3 to 9, as well as the chitosanase in an endolytic manner. Besides, the fermented SPP was recovered and displayed a better adsorption rate (up to 99.5% for the disperse dyes (red, yellow, blue, and black than the water-soluble food colorants, Allura Red AC (R40 and Tartrazine (Y4. The adsorbed R40 on the unfermented SPP and the fermented SPP was eluted by distilled water and 1 M NaOH to confirm the dye adsorption mechanism. The fermented SPP had a slightly higher adsorption capacity than the unfermented, and elution of the dye from the fermented SPP was easier than from the unfermented. The main dye adsorption mechanism of fermented SPP was physical adsorption, while the adsorption mechanism of unfermented SPP was chemical adsorption.

  8. Close cooperation between science, management and industry benefits sustainable exploitation of the Falkland Islands squid fisheries.

    Science.gov (United States)

    Arkhipkin, A; Barton, J; Wallace, S; Winter, A

    2013-10-01

    The Falkland Islands fishing industry is unique, as 60-80% of its annual catch consists of two squid species, Illex argentinus and Doryteuthis gahi. Short annual life cycles make both species susceptible to intra-annual environmental changes, resulting in large biomass fluctuations that must be addressed in management of the stocks. In the D. gahi fishery, short chains of communication between science, management and industry allow effective cooperation in the interest of long-term sustainable exploitation. The industry is responsive to short-notice requests for in-season information about the fishery. Management takes into account both scientific advice and industry recommendations, through ongoing consultations before and during the fishing seasons. As a result of this cooperation, D. gahi is one of the best managed squid fisheries in the world with local fishing companies being amongst the largest and most profitable enterprises in the Falklands economy. The I. argentinus fishery has the same potential, but a further level of cooperative management is needed as this squid is a straddling stock between several countries and the high seas. Development of a regional fisheries management organization in the South Atlantic Ocean is required to control multilateral exploitation and ensure long-term sustainability of I. argentinus stocks.

  9. Low-Frequency NMR and Nqr with a DC SQUID Amplifier

    Science.gov (United States)

    Fan, Nong-Qiang

    A sensitive Fourier-transform spectrometer based on a dc SQUID (Superconducting QUantum Interference Device) has been developed for the direct detection of nuclear magnetic resonance (NMR) in zero applied magnetic field and pure nuclear quadrupole resonance (NQR) at low frequencies. The motivation to detect zero field NMR and NQR is to provide a new high resolution spectroscopy technique at frequencies below 200 kHz to study ultra-weak interactions in chemicals and materials. By comparing the sensitivity of a SQUID amplifier with that of a conventional semiconductor amplifier, it is shown that a SQUID amplifier is essential for the direct detection of low frequency resonant signals. The spectrometer has a frequency response extending from about 10 to 200 kHz, and a recovery time (after the magnetic pulse is removed) of about 50 mus. The spectrometer is used to detect NMR spectra from Pt and Cu metal powders in a magnetic field of 6 mtesla, and NQR spectra from ^2D in a tunneling methyl group and ^{14}N in rm NH_4ClO_4. Finally, the zero field NMR spectrum from a quantum tunneling methyl group is calculated.

  10. Quantum information transfer and entanglement with SQUID qubits in cavity QED: a dark-state scheme with tolerance for nonuniform device parameter.

    Science.gov (United States)

    Yang, Chui-Ping; Chu, Shih-I; Han, Siyuan

    2004-03-19

    We investigate the experimental feasibility of realizing quantum information transfer (QIT) and entanglement with SQUID qubits in a microwave cavity via dark states. Realistic system parameters are presented. Our results show that QIT and entanglement with two-SQUID qubits can be achieved with a high fidelity. The present scheme is tolerant to device parameter nonuniformity. We also show that the strong coupling limit can be achieved with SQUID qubits in a microwave cavity. Thus, cavity-SQUID systems provide a new way for production of nonclassical microwave source and quantum communication.

  11. Emulsifying and gelling properties of weakfish myofibrillar proteins as affected by squid mantle myofibrillar proteins in a model system

    Directory of Open Access Journals (Sweden)

    Daniela Mariel Suarez

    2014-03-01

    Full Text Available The aim of the present work was to investigate the physicochemical, biochemical and functional characteristics of both the myofibrils (MF and actomyosin (AM of squid mantle (Illex argentinus and weakfish (Cynoscion guatucupa muscles, and evaluate the influence of the addition of myofibrilar proteins from the squid mantle on the physicochemical and functional properties of those of the weakfish. After extraction, purification and characterization of the MF and AM of both species, emulsions of each protein fraction from each muscle were formulated. Mixtures of the MF or AM of both species were also analyzed. The emulsifying properties were monitoring using the Emulsifying Activity Index (EAI and Emulsion Stability (ES. In addition, gel pastes were formulated from the squid mantle, weakfish muscle and the mixture of both species, and the following functional properties of the gels assessed: water holding capacity, colour, textural profile analysis (TPA (hardness, elasticity, cohesiveness, gumminess and gel strength. The EAI values of emulsions formulated with the MF of the mantle were significantly (p<0.05 higher than those formulated from those of weakfish. The incorporation of squid MF in the mixture increased the EAI values. Conversely, the highest ES values were obtained with weakfish MF, and the incorporation of MF weakfish in the mixture increased the ES values. Similar EAI and ES behaviours were observed for the AM of the corresponding species. Irrespective of the thermal treatment, the gel strength of the gelled paste of squid muscle was significantly (p<0.05 lower than that of weakfish muscle and of those obtained with the different mixtures. The behaviours of the expressible moisture (EM from the gelled pastes were similar to those of gel strength. Irrespective of the thermal treatment, the pastes formulated with a high weakfish: mantle ratio showed less water loss. The gelled pastes of squid mantle showed the highest values for whiteness

  12. Effects of environmental variations on the abundance of western winter-spring cohort of neon flying squid (Ommastrephes bartramii) in the Northwest Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    YU Wei; CHEN Xinjun; CHEN Yong; YI Qian; ZHANG Yang

    2015-01-01

    During 1995–2011, annual production of winter-spring cohort ofOmmastrephes bartramii for Chinese squid-jigging fishery has greatly fluctuated, which is closely related to the environmental conditions on the spawning and fishing grounds. To better understand how squid recruitment and abundance were influenced by ocean environmental conditions, biological and physical environmental variables including sea surface temperature (SST), SST anomaly (SSTA), chlorophylla (Chla) concentration and the Kuroshio Current were examined during years with the highest (1999), intermediate (2005), and lowest (2009) catches. Catch per unit effort (CPUE) of the squid-jigging vessels was used as an indicator of squid abundance. The results indicated that high SST and Chla concentration on the spawning ground in 1999 resulted in favorable incubation and feeding conditions for squid recruitment. Whereas the suitable spawning zone (SSZ) in 2009 shifted southward and coincided with low SST and Chla concentration, resulting in a reduction in the squid recruitment. The small difference of SSZ area in the three years suggested the SSZ provided limited influences on the variability in squid recruitment. Furthermore, high squid abundance in 1999 and 2005 was associated with warm SSTA on the fishing ground. While the cool SSTA on the fishing ground in 2009 contributed to adverse habitat for the squid, leading to extremely low abundance. It was inferred that strengthened intensity of the Kuroshio force generally yielded favorable environmental conditions forO. bartramii. Future research are suggested to focus on the fundamental research on the early life stage ofO. bartramii and mechanism of how the ocean-climate variability affects the squid abundance and spatial distribution by coupling physical model with squid biological process to explore transport path and abundance distribution.

  13. HIGH RESOLUTION AND FAST SCANNING SQUID BASED NON-DESTRUCTIVE INSPECTION SYSTEM OF NIOBIUM SHEETS FOR SRF CAVITIES

    Energy Technology Data Exchange (ETDEWEB)

    SHU, QUAN-SHENG

    2008-06-08

    Applications in high energy physics accelerators and other fields require the use of thousands of superconducting RF (SRF) cavities that are made of high purity Nb material and the purity of niobium is critical for these cavities to reach the highest accelerating fields. Tantalum is the most prolific of metal inclusions, which can cause thermal breakdown and prevent the cavities from reaching their theoretical performance limits of 45-50 MV/m, and DOE Labs are searching for a technology that could detect small impurities in superconducting Nb sheets reaching the highest possible accelerating fields. The proposed innovative SQUID-based Nondestructive system can scan Niobium sheets used in the manufacturing of SRF cavities with both high speed and high resolution. A highly sensitive SQUID system with a gradiometer probe, non-magnetic dewar, data acquisition system, and a scanning system will be developed for fast detection of impurities in planar Nb sheets. In phase I, we will modify our existing SQUID-based eddy current system to detect 100 micron size Ta defects and a great effort will focus on achieving fast scanning of a large number of niobium sheets in a shorter time and with reasonable resolution. An older system operated by moving the sample 1 mm, stopping and waiting for 1-2 seconds, then activating a measurement by the SQUID after the short settle time is modified. A preliminary designed and implemented a SQUID scanning system that is fast and is capable of scanning a 30 cm x 30 cm Nb sheet in 15 minutes by continuously moving the table at speeds up to 10 mm/s while activating the SQUID at 1mm interval is modified and reached the Phase I goal of 100mm resolution. We have successfully demonstrated the feasibility that a fast speed SQUID scanner without sacrificing the resolution of detection can be done, and a data acquisition and analysis system is also preliminary developed. The SQUID based scanner will help reach the highest accelerating field in SRF

  14. Extreme plasticity in life-history strategy allows a migratory predator (jumbo squid) to cope with a changing climate.

    Science.gov (United States)

    Hoving, Henk-Jan T; Gilly, William F; Markaida, Unai; Benoit-Bird, Kelly J; -Brown, Zachary W; Daniel, Patrick; Field, John C; Parassenti, Liz; Liu, Bilin; Campos, Bernardita

    2013-07-01

    Dosidicus gigas (jumbo or Humboldt squid) is a semelparous, major predator of the eastern Pacific that is ecologically and commercially important. In the Gulf of California, these animals mature at large size (>55 cm mantle length) in 1-1.5 years and have supported a major commercial fishery in the Guaymas Basin during the last 20 years. An El Niño event in 2009-2010, was accompanied by a collapse of this fishery, and squid in the region showed major changes in the distribution and life-history strategy. Large squid abandoned seasonal coastal-shelf habitats in 2010 and instead were found in the Salsipuedes Basin to the north, an area buffered from the effects of El Niño by tidal upwelling and a well-mixed water column. The commercial fishery also relocated to this region. Although large squid were not found in the Guaymas Basin from 2010 to 2012, small squid were abundant and matured at an unusually small mantle-length (gigas to rapidly adapt to and cope with El Niño. This ability is likely to be an important factor in conjunction with longerterm climate-change and the potential ecological impacts of this invasive predator on marine ecosystems.

  15. ESR studies on the thermal decomposition of trimethylamine oxide to formaldehyde and dimethylamine in jumbo squid (Dosidicus gigas) extract.

    Science.gov (United States)

    Zhu, Junli; Jia, Jia; Li, Xuepeng; Dong, Liangliang; Li, Jianrong

    2013-12-15

    The effects of ferrous iron, heating temperature and different additives on the decomposition of trimethylamine oxide (TMAO) to formaldehyde (FA) and dimethylamine (DMA) and generation of free radicals in jumbo squid (Dosidicus gigas) extract during heating were evaluated by electron spin resonance (ESR). The thermal decomposition of TMAO to TMA, DMA and FA and free radical signals was observed in squid extract, whereas no DMA, FA and free radical signals were detected in cod extract or in aqueous TMAO solution in vitro at high temperatures. Significant increase in levels of DMA, FA and radicals intensity were observed in squid extract and TMAO solution in the presence of ferrous iron with increasing temperature. Hydrogen peroxide stimulated the production of DMA, FA and ESR signals in squid extract, while citric acid, trisodium citrate, calcium chloride, tea polyphenols and resveratrol had the opposite effect. Similar ESR spectra of six peaks regarded as amminium radical were detected in the squid extract and TMAO-iron(II) solution, suggesting that the amminium radical was involved in the decomposition of TMAO.

  16. Deep-sea in situ observations of gonatid squid and their prey reveal high occurrence of cannibalism

    Science.gov (United States)

    Hoving, H. J. T.; Robison, B. H.

    2016-10-01

    In situ observations are rarely applied in food web studies of deep-sea organisms. Using deep-sea observations obtained by remotely operated vehicles in the Monterey Submarine Canyon, we examined the prey choices of more than 100 individual squids of the genus Gonatus. Off the California coast, these squids are abundant, semelparous (one reproductive cycle) oceanic predators but their diet has remained virtually unknown. Gonatus onyx and Gonatus berryi were observed to feed on mesopelagic fishes (in particular the myctophid Stenobrachius leucopsarus) as often as on squids but inter-specific differences in feeding were apparent. Gonatids were the most common squid prey and while cannibalism occurred in both species it was particularly high in Gonatus onyx (42% of all prey items). Typically, the size of prey was similar to the size of the predator but the squids were also seen to take much larger prey. Postjuvenile gonatids are opportunistic predators that consume nektonic members of the meso-and bathypelagic communities, including their own species. Such voracious feeding is likely necessary to support the high energetic demands associated with the single reproductive event; and for females the long brooding period during which they must depend on stored resources.

  17. MRX measurement setup employing a directly-coupled high-T{sub c} SQUID with slotted pickup loop

    Energy Technology Data Exchange (ETDEWEB)

    Guillaume, Alexander; Ludwig, Frank; Scholtyssek, Jan M.; Schilling, Meinhard [Institut fuer Elektrische Messtechnik und Grundlagen der Elektrotechnik, Technische Universitaet Braunschweig, Hans-Sommer-Str. 66, D-38106 Braunschweig (Germany)

    2013-07-01

    Magnetic nanoparticles (MNP) are employed in a wide range of medical and industrial applications. Besides other characterization techniques, magnetorelaxometry (MRX) is well established. In our MRX setup, we employ a directly-coupled high-T{sub c} SQUID with a slotted pickup loop as magnetic field sensor. The whole setup is installed in a magnetically shielded room. The MNP sample, which is attached to a glass dipstick containing the SQUID, is magnetized by a pair of Helmholtz-coils. In order to prevent flux vortices from entering the SQUID, the sensor is aligned parallel to the magnetizing field so that only the stray field of the MNP is measured. The aligning process is accomplished by using three alignment screws. Hence, the SQUID only measures 1 ppm of the magnetizing field which is in the order of several mT. Since the magnetic nanoparticles are placed in liquid nitrogen, the relaxation time constant increases in comparison to a measurement of the particles at room temperature allowing to investigate particle sizes down to 10 nm. Here, we present our MRX setup and the employed SQUID design. We evaluate its performance by carrying out MRX measurements on immobilized MNPs.

  18. Seasonal Habitat Patterns of Japanese Common Squid (Todarodes Pacificus Inferred from Satellite-Based Species Distribution Models

    Directory of Open Access Journals (Sweden)

    Irene D. Alabia

    2016-11-01

    Full Text Available The understanding of the spatio-temporal distributions of the species habitat in the marine environment is central to effectual resource management and conservation. Here, we examined the potential habitat distributions of Japanese common squid (Todarodes pacificus in the Sea of Japan during a four-year period. The seasonal patterns of preferential habitat were inferred from species distribution models, built using squid occurrences detected from night-time visible images and remotely-sensed environmental factors. The predicted squid habitat (i.e., areas with high habitat suitability revealed strong seasonal variability, characterized by a reduction of potential habitat, confined off of the southern part of the basin during the winter–spring period (December–May. Apparent expansion of preferential habitat occurred during summer–autumn months (June–November, concurrent with the formation of highly suitable habitat patches in certain regions of the Sea of Japan. These habitat distribution patterns were in response to changes in oceanographic conditions and synchronous with seasonal migration of squid. Moreover, the most important variables regulating the spatio-temporal patterns of suitable habitat were sea surface temperature, depth, sea surface height anomaly, and eddy kinetic energy. These variables could affect the habitat distributions through their impacts on growth and survival of squid, local nutrient transport, and the availability of favorable spawning and feeding grounds.

  19. The study on fishing ground of neon flying squid, Ommastrephes bartrami, and ocean environment based on remote sensing data in the Northwest Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    FAN Wei; WU Yumei; CUI Xuesen

    2009-01-01

    The relationships between the neon flying squid, Ommastrephes bartrami, and the relative ocean environmental factors are analyzed. The environmental factors collected are sea surface temperature (SST), chlorophyll concentration (Chl-a) and sea surface height (SSH) from NASA, as well as the yields of neon flying squid in the North Pacific Ocean. The results show that the favorable temperature for neon flying squid living is 10℃-22℃ and the favorite temperature is between 15℃-17℃. The Chl-a concentration is 0.1-0.6 mg/m3. When Chl-a concentration changes to 0.12-0.14 mg/m3, the probability of forming fishing ground becomes very high. In most fishing grounds,the SSH is higher than the mean SSH. The generalized additive model (GAM) was applied to analyze the correlations between neon flying squid and ocean environmental factors. Every year, squids migrate northward from June to August and return southward during October-November, and the characteristics of the both migrations are very different. When squids migrate to the north, most relationships between the yields and SST are positive. The relationships are negative when squids move to southward. The relationships between the yields and Chl-a concentrations are negative from June to October, and insignificant in November. There is no obvious correlation between the catches of squid and longitude, but good with latitude.

  20. Environmental factors which affect growth of Japanese common squid, Todarodes pacificus, analyzed by a bioenergetics model coupled with a lower trophic ecosystem model

    Science.gov (United States)

    Kishi, Michio J.; Nakajima, Kazuto; Fujii, Masahiko; Hashioka, Taketo

    2009-09-01

    Bioenergetics model is applied to Japanese common squid, Todarodes pacificus. The temporal change of wet weight of common squid, which migrates in the Sea of Japan, is simulated. The time dependent horizontal distribution of prey is calculated a priori by 3-D coupled physical-biological model. The biological model NEMURO (North Pacific Ecosystem Model for Understanding Regional Oceanography) is used to simulate the lower-trophic ecosystem including three kinds of zooplankton biomass two of which is used as prey of common squid. A bioenergetics model reproduced appropriate growth curve of common squid, migrating in the North Pacific and the Sea of Japan. The results show that the wet weight of common squid in the northern Sea of Japan is heavier than that migrating in the central Sea of Japan, because prey density of the northern Sea of Japan is higher than that of the central Sea of Japan. We also investigate the wet weight anomaly for a global warming scenario. In this case, wet weight of common squid decreases because water temperature exceeds the optimum temperature for common squid. This result indicates that migration route and spawning area of common squid might change with global warming.

  1. Conformational changes in proteins recovered from jumbo squid (Dosidicus gigas) muscle through pH shift washing treatments.

    Science.gov (United States)

    Cortés-Ruiz, Juan A; Pacheco-Aguilar, Ramón; Ramírez-Suárez, Juan C; Lugo-Sánchez, Maria E; García-Orozco, Karina D; Sotelo-Mundo, Rogerio R; Peña-Ramos, Aida

    2016-04-01

    Conformational and thermal-rheological properties of acidic (APC) and neutral (NPC) protein concentrates were evaluated and compared to those of squid (Dosidicus gigas) muscle proteins (SM). Surface hydrophobicity, sulfhydryl status, secondary structure profile, differential scanning calorimetry and oscillatory dynamic rheology were used to evaluate the effect of treatments on protein properties. Acidic condition during the washing process (APC) promoted structural and conformational changes in the protein present in the concentrate produced. These changes were enhanced during the heat setting of the corresponding sol. Results demonstrate that washing squid muscle under the proposed acidic conditions is a feasible technological alternative for squid-based surimi production improving its yield and gel-forming ability.

  2. Production and functional evaluation of a protein concentrate from giant squid (Dosidicus gigas) by acid dissolution and isoelectric precipitation.

    Science.gov (United States)

    Cortés-Ruiz, Juan A; Pacheco-Aguilar, Ramón; Elena Lugo-Sánchez, M; Gisela Carvallo-Ruiz, M; García-Sánchez, Guillermina

    2008-09-15

    A protein concentrate from giant squid (Dosidicus gigas) was produced under acidic conditions and its functional-technological capability evaluated in terms of its gel-forming ability, water holding capacity and colour attributes. Technological functionality of the concentrate was compared with that of squid muscle and a neutral concentrate. Protein-protein aggregates insoluble at high ionic strength (I=0.5M), were detected in the acidic concentrate as result of processing with no preclusion of its gel-forming ability during the sol-to-gel thermal transition. Even though washing under acidic condition promoted autolysis of the myosin heavy chain, the acidic concentrate displayed an outstanding ability to gel giving samples with a gel strength of 455 and 1160gcm at 75% and 90% compression respectively, and an AA folding test grade indicative of high gel strength, elasticity, and cohesiveness. The process proved to be a good alternative for obtaining a functional protein concentrate from giant squid muscle.

  3. Analysis of the tenderisation of jumbo squid (Dosidicus gigas) meat by ultrasonic treatment using response surface methodology.

    Science.gov (United States)

    Hu, Yaqin; Yu, Hiaxia; Dong, Kaicheng; Yang, Shuibing; Ye, Xingqian; Chen, Shiguo

    2014-10-01

    Due to its unique structure, jumbo squid (Dosidicus gigas) meat is sensitive to heat treatment, which makes the traditional squid products taste tough and hard. This study aimed to tenderise jumbo squid meat through ultrasonic treatment. Response surface methodology (RSM) was used to predict the tenderising effect of various treatment conditions. According to the results of RSM, the optimal conditions appeared to be a power of 186.9 W, a frequency of 25.6 kHz, and a time of 30.8 min, and the predicted values of flexibility and firmness under these optimal conditions were 2.40 mm and 435.1 g, respectively. Protein degradation and a broken muscle fibre structure were observed through histological assay and SDS-PAGE, which suggests a satisfactory tenderisation effect.

  4. Fabrication of high sensitivity 3D nanoSQUIDs based on a focused ion beam sculpting technique

    Science.gov (United States)

    De Leo, Natascia; Fretto, Matteo; Lacquaniti, Vincenzo; Granata, Carmine; Vettoliere, Antonio

    2016-09-01

    In this paper a nanofabrication process, based on a focused ion beam (FIB) nanosculpting technique, for high sensitivity three-dimensional nanoscale superconducting quantum interference devices (nanoSQUIDs) is reported. The crucial steps of the fabrication process are described, as are some peculiar features of the superconductor-normal metal-insulator-superconductor (SNIS) Josephson junctions, which may useful for applications in cryocooler systems. This fabrication procedure is employed to fabricate sandwich nanojunctions and high sensitivity nanoSQUIDs. Specifically, the superconductive nanosensors have a rectangular loop of 1 × 0.2-0.4 μm2 interrupted by two square Nb/Al-AlO x /Nb SNIS Josephson junctions with side lengths of 0.3 μm. The characterization of a typical nanoSQUID has been carried out and a spectral density of magnetic flux noise as low as 0.8 μΦ0 Hz-1/2 has been measured.

  5. Influence of inductance induced noise in an YBa2Cu3O7 dc-SQUID at high operation temperatures

    DEFF Research Database (Denmark)

    Nilsson, P. Å.; Claeson, T.; Hansen, J. B.;

    1994-01-01

    The voltage modulation depth of a high T(c) dc-SQUID was measured at temperatures close to T(c) and compared to a model by Enpuku et al. where the flux noise from the SQUID inductance is taken into account. The device was an YBa2Cu3O7 dc-SQUID made on a bicrystal substrate of SrTiO3. The design...... was of the Ketchen square-washer type with an inductance of 67 pH. Measurements were made in a temperature interval from 75 to 87 K, where the voltage modulation depth changed from 4.5 to 1.4 muV in close agreement with the model....

  6. Operation of a high-T C SQUID gradiometer with a two-stage MEMS-based Joule-Thomson micro-cooler

    Science.gov (United States)

    Kalabukhov, Alexey; de Hoon, Erik-Jan; Kuit, Kristiaan; Lerou, Pieter-Paul P. P. M.; Chukharkin, Maxim; Schneiderman, Justin F.; Sepehri, Sobhan; Sanz-Velasco, Anke; Jesorka, Aldo; Winkler, Dag

    2016-09-01

    Practical applications of high-T C superconducting quantum interference devices (SQUIDs) require cheap, simple in operation, and cryogen-free cooling. Mechanical cryo-coolers are generally not suitable for operation with SQUIDs due to their inherent magnetic and vibrational noise. In this work, we utilized a commercial Joule-Thomson microfluidic two-stage cooling system with base temperature of 75 K. We achieved successful operation of a bicrystal high-T C SQUID gradiometer in shielded magnetic environment. The micro-cooler head contains neither moving nor magnetic parts, and thus does not affect magnetic flux noise of the SQUID even at low frequencies. Our results demonstrate that such a microfluidic cooling system is a promising technology for cooling of high-T C SQUIDs in practical applications such as magnetic bioassays.

  7. Role of aerobic and anaerobic circular mantle muscle fibers in swimming squid: electromyography.

    Science.gov (United States)

    Bartol, I K

    2001-02-01

    Circular mantle muscle of squids and cuttlefishes consists of distinct zones of aerobic and anaerobic muscle fibers that are thought to have functional roles analogous to red and white muscle in fishes. To test predictions of the functional role of the circular muscle zones during swimming, electromyograms (EMGs) in conjunction with video footage were recorded from brief squid Lolliguncula brevis (5.0-6.8 cm dorsal mantle length, 10.9-18.3 g) swimming in a flume at speeds of 3-27 cm s(-1). In one set of experiments, in which EMGs were recorded from electrodes intersecting both the central anaerobic and peripheral aerobic circular mantle muscles, electrical activity was detected during each mantle contraction at all swimming speeds, and the amplitude and frequency of responses increased with speed. In another set of experiments, in which EMGs were recorded from electrodes placed in the central anaerobic circular muscle fibers alone, electrical activity was not detected during mantle contraction until speeds of about 15 cm s(-1), when EMG activity was sporadic. At speeds greater than 15 cm s(-1), the frequency of central circular muscle activity subsequently increased with swimming speed until maximum speeds of 21-27 cm s(-1), when muscular activity coincided with the majority of mantle contractions. These results indicate that peripheral aerobic circular muscle is used for low, intermediate, and probably high speeds, whereas central anaerobic circular muscle is recruited at intermediate speeds and used progressively more with speed for powerful, unsteady jetting. This is significant because it suggests that there is specialization and efficient use of locomotive muscle in squids.

  8. CO2-level Dependent Effects of Ocean Acidification on Squid, Doryteuthis pealeii, Early Life History

    KAUST Repository

    Zakroff, Casey J.

    2013-12-01

    Ocean acidification is predicted to lead to global oceanic decreases in pH of up to 0.3 units within the next 100 years. However, those levels are already being reached currently in coastal regions due to natural CO2 variability. Squid are a vital component of the pelagic ecosystem, holding a unique niche as a highly active predatory invertebrate and major prey stock for upper trophic levels. This study examined the effects of a range of ocean acidification regimes on the early life history of a coastal squid species, the Atlantic longfin squid, Doryteuthis pealeii. Eggs were raised in a flow-through ocean acidification system at CO2 levels ranging from ambient (400ppm) to 2200ppm. Time to hatching, hatching efficiency, and hatchling mantle lengths, yolk sac sizes, and statoliths were all examined to elucidate stress effects. Delays in hatching time of at least a day were seen at exposures above 1300ppm in all trials under controlled conditions. Mantle lengths were significantly reduced at exposures above 1300 ppm. Yolk sac sizes varied between CO2 treatments, but no distinct pattern emerged. Statoliths were increasingly porous and malformed as CO2 exposures increased, and were significantly reduced in surface area at exposures above 1300ppm. Doryteuthis pealeii appears to be able to withstand acidosis stress without major effects up to 1300ppm, but is strongly impacted past that threshold. Since yolk consumption did not vary among treatments, it appears that during its early life stages, D. pealeii reallocates its available energy budget away from somatic growth and system development in order to mitigate the stress of acidosis.

  9. A novel squid pen chitosan/hydroxyapatite/β-tricalcium phosphate composite for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Shavandi, Amin, E-mail: amin.shavandi@postgrad.otago.ac.nz [Department of Food Sciences, University of Otago, Dunedin (New Zealand); Department of Applied Sciences, University of Otago, Dunedin (New Zealand); Bekhit, Alaa El-Din A. [Department of Food Sciences, University of Otago, Dunedin (New Zealand); Sun, Zhifa; Ali, Azam [Department of Physics, University of Otago, Dunedin (New Zealand); Gould, Maree [Department of Anatomy, University of Otago, Dunedin (New Zealand)

    2015-10-01

    Squid pen chitosan was used in the fabrication of biocomposite scaffolds for bone tissue engineering. Hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP) obtained from waste mussel shells were used as the calcium phosphate source. The composite was prepared using 2.5% tripolyphosphate (TPP) and 1% glycerol as a cross-linker and plasticizer, respectively. The weight percent (wt.%) ratios of the ceramic components in the composite were 20/10/70, 30/20/50 and 40/30/30 (HA/β-TCP/Chi). The biodegradation rate and structural properties of the scaffolds were investigated. Scanning electron microscopy (SEM) and microCT(μCT) results indicated that the composites have a well defined lamellar structure with an average pore size of 200 μm. The porosity of the composites decreased from 88 to 56% by increasing the ratio of HA/β-TCP from 30 to 70%. After 28 days of incubation in a physiological solution, the scaffolds were degraded by approximately 30%. In vitro investigations showed that the composites were cytocompatible and supported the growth of L929 and Saos-2 cells. The obtained data suggests that the squid pen chitosan composites are potential candidates for bone regeneration. - Highlights: • Biocomposite scaffolds were made from mussel shells HA and β-TCP, and squid pin chitosan. • The porosity of the composites decreased with an increase in HA/β-TCP ratio. • Composites were cytocompatible and supported the growth of L929 and Saos-2 cells. • Composite containing 50% HA and β-TCP had the best mechanical properties.

  10. Micro-SQUIDs based on MgB2 nano-bridges for NEMS readout

    Science.gov (United States)

    Lolli, L.; Li, T.; Portesi, C.; Taralli, E.; Acharya, N.; Chen, K.; Rajteri, M.; Cox, D.; Monticone, E.; Gallop, J.; Hao, L.

    2016-10-01

    We show the results obtained from the fabrication and characterisation of MgB2 loops with two nano-bridges as superconducting weak links. These ring structures are made to operate as superconducting quantum interference devices and are investigated as readout system for cryogenics NEMS resonators. The nano-constrictions are fabricated by EBL and ion beam milling. The SQUIDs are characterised at different temperatures and measurements of the noise levels have been performed. The devices show high critical current densities and voltage modulations under applied magnetic field, close to the critical temperatures.

  11. Design and characterization of TES bolometers and SQUID readout electronics for a balloon-borne application

    CERN Document Server

    Hubmayr, Johannes; Bissonnette, Eric; Dobbs, Matt; Hanany, Shaul; Lee, Adrian T; MacDermid, Kevin; Meng, Xiaofan; Sagiv, Ilan; Smecher, Graeme

    2009-01-01

    We present measurements of the electrical and thermal properties of new arrays of bolometeric detectors that were fabricated as part of a program to develop bolometers optimized for the low photon background of the EBEX balloon-borne experiment. An array consists of 140 spider-web transition edge sensor bolometers microfabricated on a 4" diameter silicon wafer. The designed average thermal conductance of bolometers on a proto-type array is 32 pW/K, and measurements are in good agreement with this value. The measurements are taken with newly developed, digital frequency domain multiplexer SQUID readout electronics.

  12. Invasive range expansion by the Humboldt squid, Dosidicus gigas, in the eastern North Pacific.

    Science.gov (United States)

    Zeidberg, Louis D; Robison, Bruce H

    2007-07-31

    A unique 16-year time series of deep video surveys in Monterey Bay reveals that the Humboldt squid, Dosidicus gigas, has substantially expanded its perennial geographic range in the eastern North Pacific by invading the waters off central California. This sustained range expansion coincides with changes in climate-linked oceanographic conditions and a reduction in competing top predators. It is also coincident with a decline in the abundance of Pacific hake, the most important commercial groundfish species off western North America. Recognizing the interactive effects of multiple changes in the environment is an issue of growing concern in ocean conservation and sustainability research.

  13. Measurement of the magnetic moment in a cold worked 304 stainless steel using HTS SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Park, D.G. [Korea Atomic Energy Research Institute, Yusung P.O. Box 105, Taejon 305-600 (Korea, Republic of)], E-mail: dwkim1@kaeri.re.kr; Kim, D.W.; Angani, C.S. [Korea Atomic Energy Research Institute, Yusung P.O. Box 105, Taejon 305-600 (Korea, Republic of); Timofeev, V.P. [B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Science of Ukraine, 47 Lenin Ave, Kharkov 61103 (Ukraine); Cheong, Y.M. [Korea Atomic Energy Research Institute, Yusung P.O. Box 105, Taejon 305-600 (Korea, Republic of)

    2008-10-15

    The magnetic properties of stainless steel have been investigated using a radio frequency (RF) high-temperature superconductivity (HTS) SQUID (Superconducting QUantum Interference Device)-based susceptometer. The nuclear grade 304 stainless steel is nonmagnetic at a normal condition but it changes to a partially ferromagnetic state associated with martensitic transformation under a plastic deformation. The magnetic moment of the 304 stainless steels was increased with an increasing cold work rate, and decreased with an increasing annealing temperature. The change of mechanical properties such as yield strength and ultimate tensile strength (UTS) are also analyzed in terms of deformation-induced martensitic transformation.

  14. HTS SQUID application for measuring the magnetic properties of AISI type 316L(N) steel

    Energy Technology Data Exchange (ETDEWEB)

    Park, D.G. E-mail: dgpark@nanum.kaeri.re.kr; Kim, D.W.; Hong, J.H.; Timofeev, V.P.; Kim, C.G

    2000-06-02

    A portable RF HTS SQUID-based susceptometer was used for small-size magnetized sample testing in weak DC (up to 200 A/m) and AC (up to 4 A/m) magnetic fields. The system resolution for the magnetic moment is of the order of 1.6x10{sup -10} A m{sup 2}. The measured DC susceptibility of a tested sample of Gd{sub 88}La{sub 12} agrees well with the value obtained by using a commercial liquid helium susceptometer. The measured volume susceptibility of AISI type 316L(N) steel increases after fatigue due to the microcrack induced by cyclic stress.

  15. Wormhole spacetimes, CTCs and chronology protection in a dc-SQUID array

    CERN Document Server

    Sabín, Carlos

    2016-01-01

    We present an analog quantum simulator of spacetimes containing traversable wormholes. A suitable spatial dependence in the external bias of a dc-SQUID array mimics the propagation of light in a 1D wormhole background. The impedance of the array places severe limitations on the type of spacetime that we are able to implement. However, we find that wormhole throat radius in the sub-mm range are achievable. We show how to modify this spacetime in order to allow the existence of closed timelike curves. The quantum fluctuations of the phase associated to the finite array impedance might be seen as an analogue of Hawking's chronology protection mechanism.

  16. High-temperature superconducting YBCO dc SQUID gradiometers fabricated on STO bicrystal substrates

    Energy Technology Data Exchange (ETDEWEB)

    Carr, C.; Eulenburg, A.; Romans, E.J.; Pegrum, C.M.; Donaldson, G.B. [Department of Physics and Applied Physics, University of Strathclyde, Glasgow (United Kingdom)

    1998-11-01

    HTS dc gradiometers have been fabricated with slots and flux dams in their SQUID washers. Using a single layer of YBCO, the gradient sensitivity is limited by the sensing magnetometer in the centre of the structure. The spatial response of such devices has been measured experimentally indicating that single layer devices, in terms of gradient sensitivity, have characteristics that deviate slightly from idealized first order gradiometers. The flux noise of these devices is discussed with particular emphasis on their unshielded low frequency noise properties. We also discuss the effect of different cooldown procedures on the flux noise. (author)

  17. Quantum simulation of traversable wormhole spacetimes in a dc-SQUID array

    Science.gov (United States)

    Sabín, Carlos

    2016-10-01

    We present an analog quantum simulator of spacetimes containing traversable wormholes. A suitable spatial dependence in the external bias of a dc-SQUID array mimics the propagation of light in a 1D wormhole background. The impedance of the array places severe limitations on the type of spacetime that we are able to implement. However, we find that a wormhole throat radius in the submillimeter range is achievable. We show how to modify this spacetime in order to allow the existence of closed timelike curves. The quantum fluctuations of the phase associated to the finite array impedance might be seen as an analog of Hawking's chronology-protection mechanism.

  18. Sensory, chemical and bacteriological changes during storage of iced squid ( Todaropsis eblanae )

    DEFF Research Database (Denmark)

    Paarup, T.; Sanchez, J.A.; Moral, A.

    2002-01-01

    psychrophilic and had a requirement for NaCl. 16S rDNA sequence analyses identified the strains as belonging to the genus Pseudoalteromonas . Shewanella putrefaciens , Pseudoalteromonas sp. and Pseudomonas sp. dominated in spoiled gutted squid. Identification of strains from the stomach and digestive gland...... to spoilage through activity in the digestive gland, followed by diffusion of volatile compounds and amines to the mantle. Significance and Impact of the Study: Due to the psychrophilic nature of P. phosphoreum and Pseudoalteromonas sp., spread- plating and low temperature incubation are recommended...

  19. Non-Demolition Dispersive Measurement of a Superconducting Qubit with a Microstrip SQUID Amplifier

    CERN Document Server

    Berman, G P; Kinion, D; Tsifrinovich, V I

    2011-01-01

    We have studied the possibility of a single-shot non-demolition measurement of a superconducting qubit using a microstrip SQUID amplifier (MSA). The Johnson noise generated by all resistors in the MSA is taken into consideration. We show that a single-shot non-demolition measurement is possible with six photons in the measurement resonator. For a phase qubit inductively coupled to a measurement resonator we have obtained the expression for the mutual inductance required for measurement of the qubit state.

  20. Evaluation of alternative sources of collagen fractions from Loligo vulgaris squid mantle.

    Science.gov (United States)

    Cozza, Natascia; Bonani, Walter; Motta, Antonella; Migliaresi, Claudio

    2016-06-01

    Acid-Solubilized Collagen (ASC) and Pepsin-Solubilized Collagen (PSC) were extracted from the mantle of the common European squid, and were comparatively characterized. ASC and PSC were isolated with an extraction yield of 5.1 and 24.2% (on dry weight basis), respectively. SDS-PAGE showed that the ASC was mostly comprised of α1- and α2-chains; while the PSC presented relevant β- and γ-components. GPC analysis confirmed that both the ASC and the PSC consisted of fractions characterized by different molecular weight. Thermal denaturation behavior of ASC and PSC were followed by calorimetric and rheological analyses; denaturation temperature was estimated to be 22°C for ASC and 21°C for PSC. Amino acid composition and solubility of collagen were also investigated. Finally, the cytotoxicity of the isolated collagen was evaluated in vitro and no cytotoxic activity caused by the collagen extracts was observed. This study demonstrated that squid mantle has potential as an alternative source of collagen-derived materials.

  1. Fetal cardiac activity analysis during twin pregnancy using a multi-channel SQUID system

    Science.gov (United States)

    Costa Monteiro, E.; Schleussner, E.; Kausch, S.; Grimm, B.; Schneider, A.; Hall Barbosa, C.; Haueisen, J.

    2001-05-01

    The use of SQUID magnetometers for non-invasive in utero assessment of cardiac electrical disturbances has already been shown to be a valuable clinical tool. In this way, its applicability also for the complicated case of twin pregnancy, in which the proximity of the cardiac magnetic source of each fetus can hamper the individual analysis of cardiac electrical activity, is of clinical interest. In this paper, we present fetal magnetocardiography performed on a mother pregnant of twins with 26 weeks gestational age, measured inside a magnetically shielded room, by using two identical 31-channel low- Tc SQUID magnetometer systems. Each sensor array has been positioned over one of the fetuses, according to its heart position previously assessed with the aid of ultrasound measurements. The raw data is initially averaged in time and, afterwards, analyzed by means of time plots and isofield maps. The time recordings allow the study of the morphology of each fetus’ cardiac signal and the cardiac time intervals. The resultant equivalent dipole obtained from the isofield maps indicates the position and orientation of each fetus heart. The results agree with the ultrasound analysis performed immediately before the measurements and used to obtain the approximate location of the fetuses’ hearts. Since a distinct analysis of the cardiac electrical activity of each fetus could be achieved, the results indicate the potential of the fetal magnetocardiography in the individual antenatal diagnosis of each one of the fetuses of a twin pregnancy.

  2. Purification and characterization of trimethylamine-N-oxide demethylase from jumbo squid (Dosidicus gigas).

    Science.gov (United States)

    Fu, Xue-Yan; Xue, Chang-Hu; Miao, Ben-Chun; Liang, Jun-Ni; Li, Zhao-Jie; Cui, Feng-Xia

    2006-02-08

    Trimethylamine-N-oxide demethylase (TMAOase) was purified from Jumbo squid (Dosidicus gigas) and characterized in detail herein. The TMAOase was extracted from squid with 20 mM Tris-acetate buffer (pH 7.0) containing 1.0 M NaCl, followed by acid treatment and heat treatment. Then it was purified by deithylaminoethyl-cellulose and Sephacryl S-300 chromatography, subsequently resulting in an 839-fold purification. The molecular mass of the TMAOase was defined to be 17.5 kDa. The optimum pH of the purified TMAOase was 7.0, and its optimum temperature was confirmed to be 55 degrees C. The TMAOase was stable to heat treatment up to 50 degrees C and stable at pH 7.0-9.0. Reducing agents such as DTT, Na2SO3, and NADH were effective at activating TMAOase, and ethylenediaminetetraacetic acid, as well as Mg2+ and Ca2+, could also enhance the activity of TMAOase remarkably, whereas the TMAOase could be significantly inhibited by tea polyphenol, phytic acid and acetic acid. In addition, the TMAOase converted TMAO to dimethylamine and formaldehyde stoichiometrically with a K(m) of 26.2 mM.

  3. Characteristics of deacetylation and depolymerization of β-chitin from jumbo squid (Dosidicus gigas) pens.

    Science.gov (United States)

    Jung, Jooyeoun; Zhao, Yanyun

    2011-09-27

    This study evaluated the deacetylation characteristics of β-chitin from jumbo squid (Dosidicus gigas) pens by using strongly alkaline solutions of NaOH or KOH. Taguchi design was employed to investigate the effect of reagent concentration, temperature, time, and treatment step on molecular mass (MM) and degree of deacetylation (DDA) of the chitosan obtained. The optimal treatment conditions for achieving high MM and DDA of chitosan were identified as: 40% NaOH at 90°C for 6h with three separate steps (2h+2h+2h) or 50% NaOH at 90°C for 6h with one step, or 50% KOH at 90°C for 4h with three steps (1h+1h+2h) or 6h with one step. The most important factor affecting DDA and MM was temperature and time, respectively. The chitosan obtained was then further depolymerized by cellulase or lysozyme with cellulase giving a higher degradation ratio, lower relative viscosity, and a larger amount of reducing-end formations than that of lysozyme due to its higher susceptibility. This study demonstrated that jumbo squid pens are a good source of materials to produce β-chitosan with high DDA and a wide range of MM for various potential applications.

  4. Reversible stress softening of collagen based networks from the jumbo squid mantle (Dosidicus gigas).

    Science.gov (United States)

    Torres, F G; Troncoso, O P; Rivas, E R; Gomez, C G; Lopez, D

    2014-04-01

    Dosidicus gigas is the largest and one of the most abundant jumbo squids in the eastern Pacific Ocean. In this paper we have studied the muscle of the mantle of D. gigas (DGM). Morphological, thermal and rheological properties were assessed by means of atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential scanning calorimetry, thermogravimetry and oscillatory rheometry. This study allowed us to assess the morphological and rheological properties of a collagen based network occurring in nature. The results showed that the DGM network displays a nonlinear effect called reversible stress softening (RSS) that has been previously described for other types of biological structures such as naturally occurring cellulose networks and actin networks. We propose that the RSS could play a key role on the way jumbo squids withstand hydrostatic pressure. The results presented here confirm that this phenomenon occurs in a wider number of materials than previously thought, all of them exhibiting different size scales as well as physical conformation.

  5. Digestion of Ceramide 2-Aminoethylphosphonate, a Sphingolipid from the Jumbo Flying Squid Dosidicus gigas, in Mice.

    Science.gov (United States)

    Tomonaga, Nami; Manabe, Yuki; Sugawara, Tatsuya

    2017-04-01

    Ceramide 2-aminoethylphosphonate (CAEP), a sphingophosphonolipid containing a carbon-phosphorus bond, is frequently found in marine organisms and has a unique triene type of sphingoid base in its structure. CAEP has not been evaluated as a food ingredient, although it is generally contained in Mollusca organisms such as squids and shellfish, which are consumed worldwide. In this study, we aimed to elucidate the effects of CAEP as a food component by evaluating the digestion of CAEP extracted from the skin of the jumbo flying squid Dosidicus gigas. Our results revealed that dietary CAEP was digested to free sphingoid bases via ceramides by the mouse small intestinal mucosa. At pH 7.2, CAEP was hydrolyzed more rapidly than the major mammalian sphingolipid sphingomyelin; however, the hydrolysis of CAEP was similar to that of sphingomyelin at pH 9.0. Thus, the digestion of CAEP may be catalyzed by alkaline spingomyelinase and other enzymes. Our findings provide important insights into the digestion of the dietary sphingophosphonolipid CAEP in marine foods.

  6. SQUID measurements of remanent magnetisation in refillable 3He spin-filter cells (SFC)

    Science.gov (United States)

    Hutanu, V.; Rupp, A.; Sander-Thömmes, T.

    2007-07-01

    A strong influence of external magnetic fields on the relaxation time constant T1 of glass cells serving as reservoirs for polarised 3He, observed for various alkali metal-coated cells made of different glass types, was initially associated with the presence of a large number of ferromagnetic clusters on the glass surface. Later experiments showed the presence of the so-called “ T1 hysteresis” phenomenon with a similar distinctiveness also in uncoated cells made of pure synthetic quartz glass. It suggests that the origin of such a relaxation is a macroscopic magnetisation in the bulk of the cell. We present the results of a multi-SQUID system investigation on magnetised and non-magnetised quartz glass cells, Cs coated as well as bare wall, to be used as neutron spin filters at HMI Berlin. The presence of a macroscopic remanent magnetic moment in the cells after their exposition to external magnetic fields has been experimentally shown. More than 80% of the remanent magnetic moment of the magnetised cells was found to be concentrated in the region of the glass valves. SQUID measurements reveal the existence of some remanent magnetisation in all valve parts and also in the vacuum grease, but most magnetic are the plastic parts and the O-ring. Different valve and sealing types have been compared in order to find the less magnetisable one.

  7. SQUID measurements of remanent magnetisation in refillable {sup 3}He spin-filter cells (SFC)

    Energy Technology Data Exchange (ETDEWEB)

    Hutanu, V. [Hahn-Meitner-Institut Berlin, Department SF2, Glienicker Str. 100, D-14109 Berlin (Germany)]. E-mail: vladimir.hutanu@frm2.tum.de; Rupp, A. [Hahn-Meitner-Institut Berlin, Department SF2, Glienicker Str. 100, D-14109 Berlin (Germany); Sander-Thoemmes, T. [Physikalisch-Technische Bundesanstalt, Abbestr. 10-12, D-10587 Berlin (Germany)

    2007-07-15

    A strong influence of external magnetic fields on the relaxation time constant T {sub 1} of glass cells serving as reservoirs for polarised {sup 3}He, observed for various alkali metal-coated cells made of different glass types, was initially associated with the presence of a large number of ferromagnetic clusters on the glass surface. Later experiments showed the presence of the so-called 'T {sub 1} hysteresis' phenomenon with a similar distinctiveness also in uncoated cells made of pure synthetic quartz glass. It suggests that the origin of such a relaxation is a macroscopic magnetisation in the bulk of the cell. We present the results of a multi-SQUID system investigation on magnetised and non-magnetised quartz glass cells, Cs coated as well as bare wall, to be used as neutron spin filters at HMI Berlin. The presence of a macroscopic remanent magnetic moment in the cells after their exposition to external magnetic fields has been experimentally shown. More than 80% of the remanent magnetic moment of the magnetised cells was found to be concentrated in the region of the glass valves. SQUID measurements reveal the existence of some remanent magnetisation in all valve parts and also in the vacuum grease, but most magnetic are the plastic parts and the O-ring. Different valve and sealing types have been compared in order to find the less magnetisable one.

  8. The response of high-T{sub c} SQUID magnetometers to small changes in temperature

    Energy Technology Data Exchange (ETDEWEB)

    Milliken, F.P.; Koch, R.H.; Brown, S.L.; Altman, R.A.; Gallagher, W.J. [IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Haupt, S.G.; Lathrop, D.K. [Quantum Magnetics, San Diego, California 92121 (United States)

    1997-12-01

    We have investigated the response of the flux-locked output of several high-T{sub c} SQUID magnetometers to small changes in temperature and for magnetic fields 0{endash}30 {mu}T. The temperature response D{sub T}{equivalent_to}d{Phi}{sub S}/dT is observed to be linear in the applied magnetic field B{sub a} and can be as large as 500m{Phi}{sub 0}/K where {Phi}{sub S} is the flux through the SQUID loop and {Phi}{sub 0} is the flux quantum. Our measurements can be explained using a simple model that takes into account the geometry of a given device and is based on the idea that D{sub T} is due to the temperature dependence of the superconducting penetration depth. Our results can be used to optimize device performance in applications where the noise of a device is dominated by ambient temperature fluctuations. {copyright} {ital 1997 American Institute of Physics.}

  9. High temperature superconducting thin films and quantum interference devices (SQUIDs) for gradiometers

    CERN Document Server

    Graf zu Eulenburg, A

    1999-01-01

    the best balance and gradient sensitivity at 1kHz were 3x10 sup - sup 3 and 222fT/(cm sq root Hz))) respectively. The measured spatial response to a current carrying wire was in good agreement with a theoretical model. A significant performance improvement was obtained with the development of a single layer gradiometer with 13mm baseline, fabricated on 30x10mm sup 2 bicrystals. For such a device, the gradient sensitivity at 1kHz was 50fT/(cm sq root Hz)) and the gradiometer was used successfully for unshielded magnetocardiography. A parasitic effective area compensation scheme was employed with two neighbouring SQUIDs coupled in an opposite sense to the same gradiometer loop. This improved the balance from the intrinsic value of 10 sup - sup 3 to 3x10 sup - sup 5. This thesis describes several aspects of the development of gradiometers using high temperature Superconducting Quantum Interference Devices (SQUID). The pulsed laser deposition of thin films of YBa sub 2 Cu sub 3 O sub 7 sub - subdelta (YBCO) on Sr...

  10. High critical current density YBCO films and fabrication of dc-SQUIDs

    CERN Document Server

    Kuriki, S; Kawaguchi, Y; Matsuda, M; Otowa, T

    2002-01-01

    In order to improve the sensitivity of SQUID magnetometers made of high-T sub c films, we have studied the conditions of pulsed-laser deposition of YBCO films. Among the different deposition parameters examined, extensive degassing of the vacuum chamber before and precise control of the substrate temperature during the film deposition were found effective for obtaining high critical temperature T sub c and high critical current density J sub c. It was also found that the residual-resistance ratio has a clear correlation with J sub c , indicating that it can be a good, and easy to measure, index of the film quality. Films having T sub c approx 89-90 K and J sub c >= 5x10 sup 6 A cm sup - sup 2 at 77 K were used to fabricate SQUIDs without a pickup loop. Grain-boundary junctions formed on bicrystal substrates with a 30 deg. misorientation angle exhibited I sub c R sub n values of more than 100 mu V at 77 K. The well-known scaling behaviour of the relation I sub c R sub n propor to (J sup G sup B sub c) sup 1 su...

  11. Magnetometer utilizing SQUID pico-voltmeter and cooled normal pickup coil

    Energy Technology Data Exchange (ETDEWEB)

    Yang, T.Q. [Research Institute of Superconductor Science and Systems, Kyushu University, Higashi-ku, Hakozaki 6-10-1, Fukuoka 812-8581 (Japan); Yao, Kenichiro [Research Institute of Superconductor Science and Systems, Kyushu University, Higashi-ku, Hakozaki 6-10-1, Fukuoka 812-8581 (Japan); Yamasaki, Daisuke [Research Institute of Superconductor Science and Systems, Kyushu University, Higashi-ku, Hakozaki 6-10-1, Fukuoka 812-8581 (Japan); Enpuku, Keiji [Research Institute of Superconductor Science and Systems, Kyushu University, Higashi-ku, Hakozaki 6-10-1, Fukuoka 812-8581 (Japan)]. E-mail: enpuku@sc.kyushu-u.ac.jp

    2005-10-01

    Magnetometer utilizing a high-T {sub c} SQUID pico-voltometer and cooled normal pickup coil has been developed. The pickup coil was made of copper wire, and cooled to T = 77 K in order to decrease thermal noise from resistance. Total voltage noise of the SQUID pico-voltmeter with a cooled pickup coil was 124 pV/Hz{sup 1/2} and 96 pV/Hz{sup 1/2} at 100 Hz and 1 kHz, respectively, when resistance of the coil was 1.5 {omega}. The magnetic field noise of the magnetometer was 130 pT/Hz{sup 1/2} and 10 pT/Hz{sup 1/2} at 100 Hz and 1 kHz for the pickup coil with 4.4 mm diameter, respectively. Application of the magnetometer to non-destructive evaluation was presented. It is shown that small crack inside Cu plate can be detected with this system in unshielded environment. It was also shown that scanning of the pickup coil in unshielded environment is possible without degradation of the system performance.

  12. An efficient calibration method for SQUID measurement system using three orthogonal Helmholtz coils

    Science.gov (United States)

    Hua, Li; Shu-Lin, Zhang; Chao-Xiang, Zhang; Xiang-Yan, Kong; Xiao-Ming, Xie

    2016-06-01

    For a practical superconducting quantum interference device (SQUID) based measurement system, the Tesla/volt coefficient must be accurately calibrated. In this paper, we propose a highly efficient method of calibrating a SQUID magnetometer system using three orthogonal Helmholtz coils. The Tesla/volt coefficient is regarded as the magnitude of a vector pointing to the normal direction of the pickup coil. By applying magnetic fields through a three-dimensional Helmholtz coil, the Tesla/volt coefficient can be directly calculated from magnetometer responses to the three orthogonally applied magnetic fields. Calibration with alternating current (AC) field is normally used for better signal-to-noise ratio in noisy urban environments and the results are compared with the direct current (DC) calibration to avoid possible effects due to eddy current. In our experiment, a calibration relative error of about 6.89 × 10-4 is obtained, and the error is mainly caused by the non-orthogonality of three axes of the Helmholtz coils. The method does not need precise alignment of the magnetometer inside the Helmholtz coil. It can be used for the multichannel magnetometer system calibration effectively and accurately. Project supported by the “Strategic Priority Research Program (B)” of the Chinese Academy of Sciences (Grant No. XDB04020200) and the Shanghai Municipal Science and Technology Commission Project, China (Grant No. 15DZ1940902).

  13. Mitochondrial genome structure and evolution in the living fossil vampire squid, Vampyroteuthis infernalis, and extant cephalopods.

    Science.gov (United States)

    Yokobori, Shin-ichi; Lindsay, Dhugal J; Yoshida, Mari; Tsuchiya, Kotaro; Yamagishi, Akihiko; Maruyama, Tadashi; Oshima, Tairo

    2007-08-01

    Complete nucleotide sequences of mitochondrial (mt) genomes of the "living fossil" cephalopod Vampyroteuthis infernalis (Vampyromorpha) and the cuttlefish Sepia esculenta (Sepiida) were determined. The V. infernalis mt genome structure is identical to the incirrate octopod Octopus vulgaris mt genome structure, and is therefore more similar to that of the polyplacophoran Katharina tunicata, than to that of the other "living fossil" cephalopod Nautilus macromphalus. The mt genome structure of S. esculenta is identical to that of Sepia officinalis. Molecular phylogenetic analyses based on the mt protein genes from the completely sequenced cephalopod mt genomes suggested the monophyletic relationship of two myopsid squids Loligo bleekeri and Sepiotheuthis lessoniana, and the monophyletic relationship of two oegopsid squids Watasenia scintillans, and Todarodes pacificus. Sepiida appeared as the sister group of Teuthida (Myopsida + Oegopsida). The phylogenetic position of Vampyromorpha appeared as the sister group of Octopoda, although the monophyly of Vampyromorpha and Decapodiformes cannot be rejected outright by our phylogenetic analyses. The hypothesis that Vampyromorpha is basal among the coleoid cephalopods can be rejected because of low statistical support. Therefore, it is reasonable to recognize three major groups in Coleoidea--Vampyromorpha, Octopoda, and Decapodiformes.

  14. YBCO nanoSQUIDs applied to the investigation of small spin systems

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Perez, Maria Jose; Schwarz, Tobias; Woelbing, Roman; Mueller, Benedikt; Kleiner, Reinhold; Koelle, Dieter [Physikalisches Institut and Center for Collective Quantum Phenomena in LISA" +, Universitaet Tuebingen (Germany); Reiche, Christopher F.; Muehl, Thomas; Buechner, Bernd [Leibniz Institute for Solid State and Materials Research IFW Dresden (Germany); Sese, Javier [Instituto de Nanociencia de Aragon and Advanced Microscopy Laboratory, Zaragoza (Spain)

    2015-07-01

    We present the realization of ultra-sensitive YBCO nanoSQUIDs based on submicron grain boundary junctions patterned by focused ion beam milling. White flux noise down to ∝ 50nΦ{sub 0}/Hz{sup 1/2} has been achieved, yielding spin sensitivities of down to a few μ{sub B}/Hz{sup 1/2} at T=4.2 K. Moreover, we demonstrate that magnetic fields up to the tesla range can be applied, fulfilling a fundamental condition for the study of small spin systems. As a proof-of-principle we present the successful deposition of a Fe-filled carbon nanotube (∝ 40 nm in diameter and ∝ 14 μm in length) and an individual Co nanopillar (base diameter of ∝ 50 nm and height ∝ 10 nm) close to the nanoSQUID loop. We show that sub-micrometric control over the particle position lead to large magnetic coupling factors between the nano-loop and the spin system. Together with the possibility of applying large magnetic fields, the latter has allowed us to directly observe the magnetization reversal of these spin systems at different temperatures.

  15. Absolute calibration of a three-axis SQUID-cascade vector magnetometer

    Science.gov (United States)

    Schönau, T.; Zakosarenko, V.; Schmelz, M.; Stolz, R.; Anders, S.; Linzen, S.; Meyer, M.; Faßbinder, J. W. E.; Meyer, H.-G.

    2017-01-01

    We report on the absolute calibration of a three-axis SQUID-cascade vector magnetometer suited for mobile operation in the Earth’s magnetic field. It is based on low temperature superconductor (LTS) dc SQUIDs with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT Hz-1/2. Due to the cascaded operation principle, the huge dynamic range required to resolve a measurement range of more than 50 µT with sub-pT resolution is split onto several electronic channels of less demanding precision. As a result, the measurement accuracy is less vulnerable to parameter drifts. Furthermore, the intrinsic redundancy of the setup can be used to check for systematic errors of measurement. The offset as well as scaling and directional errors of the magnetometer have been obtained by the method of scalar calibration in our laboratory, resulting in a residuum with a standard deviation of less than 0.64 nT.

  16. Squids old and young: Scale-free design for a simple billboard

    Science.gov (United States)

    Packard, Andrew

    2011-03-01

    Squids employ a large range of brightness-contrast spatial frequencies in their camouflage and signalling displays. The 'billboard' of coloured elements ('spots'=chromatophore organs) in the skin is built autopoietically-probably by lateral inhibitory processes-and enlarges as much as 10,000-fold during development. The resulting two-dimensional array is a fractal-like colour/size hierarchy lying in several layers of a multilayered network. Dynamic control of the array by muscles and nerves produces patterns that recall 'half-tone' processing (cf. ink-jet printer). In the more sophisticated (loliginid) squids, patterns also combine 'continuous tones' (cf. dye-sublimation printer). Physiologists and engineers can exploit the natural colour-coding of the integument to understand nerve and muscle system dynamics, examined here at the level of the ensemble. Integrative functions of the whole (H) are analysed in terms of the power spectrum within and between ensembles and of spontaneous waves travelling through the billboard. Video material may be obtained from the author at the above address.

  17. Squids, snakes, and polarimeters: A new technique for measuring the magnetic moments of polarized beams

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, P.R.; Luccio, A.U.; Shea, T.J.; Tsoupas, N. [Brookhaven National Laboratory, Upton, New York 11973 (United States of America); Goldberg, D.A. [Lawrence Berkeley Laboratory, Berkeley, California (United States of America)

    1997-01-01

    Effective polarimetry at high energies in hadron and lepton synchrotrons has been a long-standing and difficult problem. In synchrotrons with polarized beams it is possible to cause the direction of the polarization vector of a given bunch to alternate at a frequency which is some subharmonic of the rotation frequency. This can result in the presence of lines in the beam spectrum which are due only to the magnetic moment of the beam and which are well removed from the various lines due to the charge of the beam. The magnitude of these lines can be calculated from first principles. They are many orders of magnitude weaker than the Schottky signals. Measurement of the magnitude of one of these lines would be an absolute measurement of beam polarization. For measuring magnetic field, the Superconducting Quantum Interference Device, or squid, is about five orders of magnitude more sensitive than any other transducer. Using a squid, such a measurement might be accomplished with the proper combination of shielding, pickup loop design, and filtering. The resulting instrument would be fast, non-destructive, and comparatively cheap. In addition, techniques developed in the creation of such an instrument could be used to measure the Schottky spectrum in unprecedented detail. We present specifics of a polarimeter design for the Relativistic Heavy Ion Collider (RHIC) and briefly discuss the possibility of using this technique to measure polarization at high-energy electron machines like LEP and HERA. {copyright} {ital 1997 American Institute of Physics.}

  18. Acoustic mapping of squid egg clusters and their bottom habitat in Monterey Bay, California

    Science.gov (United States)

    Foote, Kenneth G.; Hanlon, Roger T.; Iampietro, Pat J.; Kvitek, Rikk G.

    2004-10-01

    Clusters of gelatinous egg capsules, known as mops or beds, of the market squid (Loligo opalescens) were mapped in a shallow-water, sandy habitat of Monterey Bay, California. The benthic egg clusters were imaged using an EdgeTech 272-TD dual-frequency sidescan sonar towed from R/V MACGINITIE, an 8-m-long survey vessel, with data recorded on a Triton Elics International Isis digital data acquisition system. Verification of target identity was accomplished independently by video photography from a remotely operated vehicle. The survey area included a 4-km stretch of sandy seafloor between Lover's Point and Cannery Row in Monterey at depths of 15-30 m. The study area had previously been mapped using the RESON SeaBat 8101 240-kHz multibeam sonar. Resulting high-resolution bathymetric data, with 1-m resolution, were used during the survey planning and execution. Squid egg clusters were clearly visible in the very-high-resolution, 400-kHz backscatter imagery, with pixel size 10-20 cm, recorded from the towed sidescan sonar. The concentration of egg clusters was greatest along a sloping feature believed to be a submarine fault. Egg mops with diameter as small as 0.5 m were distinguishable. [Support by Sea Grant is acknowledged.

  19. An HTS X-band DC SQUID based amplifier: Modeling and development concepts

    DEFF Research Database (Denmark)

    Prokopenko, G.V.; Shitov, S.V.; Borisenko, I.V.;

    2003-01-01

    We present an X-band amplifier concept based on a HTS grain boundary dc SQUID, which allow for extended dynamic range for use with SIS mixers, e.g., as a buffer amplifier in front of an RSFQ ADC, or possibly for satellite and cellular phone communications. The proposed rf design is based on a com......We present an X-band amplifier concept based on a HTS grain boundary dc SQUID, which allow for extended dynamic range for use with SIS mixers, e.g., as a buffer amplifier in front of an RSFQ ADC, or possibly for satellite and cellular phone communications. The proposed rf design is based...... on a combination of single-layer slot and coplanar lines forming novel input and output circuits. The following parameters (per stage) are obtained via simulation for central frequency 11 GHz: bandwidth 0.5-1 GHz, power gain 11-12 dB, noise temperature 5-10 K. A saturation product as high as 500-1000 K...

  20. High-J{sub c} superconducting YBCO thin films for SQUIDs

    Energy Technology Data Exchange (ETDEWEB)

    Katsaros, A.; Savvides, N.; Foley, C. [CSIRO, Sydney, NSW (Australia). Applied Physics

    1996-12-31

    Full text: High critical current density, J{sub c}, and reproducibility of film quality are major issues in high-T{sub c} superconducting device technology. Because many factors such as substrate quality, deposition parameters and film stoichiometry impact on film quality the growth of high-J{sub c} YBa{sub 2}Cu{sub 3}O{sub 7} thin films suitable for devices is a demanding task. For optimum device performance c-axis epitaxial films are required with smooth surfaces, controlled microstructure and crystalline orientation, high T{sub c} (> 87 K) and high J{sub c} (> 1x10{sup 6} A cm{sup -2}). Consequently a stable platform in film quality is critical in developing and maintaining world class device technology. In previous Wagga meetings and elsewhere we presented details of our thin film deposition system, results of film growth studies, techniques of film characterisation and SQUID performance. In this paper we present transport properties and lattice parameters for a large number of films deposited over a period of ten months using a single target and under similar sputtering conditions. The data serve to illustrate the level of reproducibility of our deposition technology while closer examination of the data reveal some interesting `correlations` among properties. We have used these correlations to assist us to control both the deposition of films and subsequent processing into test structures and SQUIDs 5 refs.

  1. Compensation for longitudinal chromatic aberration in the eye of the firefly squid, Watasenia scintillans.

    Science.gov (United States)

    Kröger, Ronald H H; Gislén, Anna

    2004-01-01

    The camera eyes of fishes and cephalopods have come forth by convergent evolution. In a variety of vertebrates capable of color vision, longitudinal chromatic aberration (LCA) of the optical system is corrected for by the exactly tuned longitudinal spherical aberration (LSA) of the crystalline lens. The LSA leads to multiple focal lengths, such that several wavelengths can be focused on the retina. We investigated whether that is also the case in the firefly squid (Watasenia scintillans), a cephalopod species that is likely to have color vision. It was found that the lens of W. scintillans is virtually free of LSA and uncorrected for LCA. However, the eye does not suffer from LCA because of a banked retina. Photoreceptors sensitive to short and long wavelengths are located at appropriate distances from the lens, such that they receive well-focused images. Such a design is an excellent solution for the firefly squid because a large area of the retina is monochromatically organized and it allows for double use of the surface area in the dichromatically organized part of the retina. However, it is not a universal solution since compensation for LCA by a banked retina requires that eye size and/or spectral separation between photopigments is small.

  2. Adverse effects of ocean acidification on early development of squid (Doryteuthis pealeii.

    Directory of Open Access Journals (Sweden)

    Maxwell B Kaplan

    Full Text Available Anthropogenic carbon dioxide (CO2 is being absorbed into the ocean, altering seawater chemistry, with potentially negative impacts on a wide range of marine organisms. The early life stages of invertebrates with internal and external aragonite structures may be particularly vulnerable to this ocean acidification. Impacts to cephalopods, which form aragonite cuttlebones and statoliths, are of concern because of the central role they play in many ocean ecosystems and because of their importance to global fisheries. Atlantic longfin squid (Doryteuthis pealeii, an ecologically and economically valuable taxon, were reared from eggs to hatchlings (paralarvae under ambient and elevated CO2 concentrations in replicated experimental trials. Animals raised under elevated pCO2 demonstrated significant developmental changes including increased time to hatching and shorter mantle lengths, although differences were small. Aragonite statoliths, critical for balance and detecting movement, had significantly reduced surface area and were abnormally shaped with increased porosity and altered crystal structure in elevated pCO2-reared paralarvae. These developmental and physiological effects could alter squid paralarvae behavior and survival in the wild, directly and indirectly impacting marine food webs and commercial fisheries.

  3. Adverse effects of ocean acidification on early development of squid (Doryteuthis pealeii).

    Science.gov (United States)

    Kaplan, Maxwell B; Mooney, T Aran; McCorkle, Daniel C; Cohen, Anne L

    2013-01-01

    Anthropogenic carbon dioxide (CO2) is being absorbed into the ocean, altering seawater chemistry, with potentially negative impacts on a wide range of marine organisms. The early life stages of invertebrates with internal and external aragonite structures may be particularly vulnerable to this ocean acidification. Impacts to cephalopods, which form aragonite cuttlebones and statoliths, are of concern because of the central role they play in many ocean ecosystems and because of their importance to global fisheries. Atlantic longfin squid (Doryteuthis pealeii), an ecologically and economically valuable taxon, were reared from eggs to hatchlings (paralarvae) under ambient and elevated CO2 concentrations in replicated experimental trials. Animals raised under elevated pCO2 demonstrated significant developmental changes including increased time to hatching and shorter mantle lengths, although differences were small. Aragonite statoliths, critical for balance and detecting movement, had significantly reduced surface area and were abnormally shaped with increased porosity and altered crystal structure in elevated pCO2-reared paralarvae. These developmental and physiological effects could alter squid paralarvae behavior and survival in the wild, directly and indirectly impacting marine food webs and commercial fisheries.

  4. Lateral line analogue aids vision in successful predator evasion for the brief squid, Lolliguncula brevis.

    Science.gov (United States)

    York, Carly A; Bartol, Ian K

    2014-07-15

    Cephalopods have visual and mechanoreception systems that may be employed to sense and respond to an approaching predator. While vision presumably plays the dominant role, the importance of the lateral line analogue for predator evasion has not been examined in cephalopods. To test the respective roles of vision and the lateral line analogue, brief squid, Lolliguncula brevis, were observed in the presence of summer flounder, Paralichthys dentatus, under light and dark conditions with their lateral line analogue intact and ablated. Hair cell ablation was achieved through a pharmacological technique used for the first time on a cephalopod. The proportion of predator-prey interactions survived was significantly higher in the light non-ablated and light ablated groups compared with the dark ablated group. The mean number of interactions survived varied across treatment groups with the light non-ablated group having significantly more success than the light ablated, dark non-ablated and dark ablated groups. These findings demonstrate that although vision is the primary sense, the lateral line analogue also contributes to predator evasion in squid.

  5. Polycyclic aromatic hydrocarbons in commercial squids from different geographical origins: levels and risks for human consumption.

    Science.gov (United States)

    Gomes, Filipa; Oliveira, Marta; Ramalhosa, Maria João; Delerue-Matos, Cristina; Morais, Simone

    2013-09-01

    The concentrations of 18 polycyclic aromatic hydrocarbons (PAHs) were determined in five commercially valuable squid species from different geographical origins (Atlantic, Indic and Pacific Oceans). Out of the 18 quantified PAHs (the 16 PAHs considered by US EPA as priority pollutants, dibenzo(a,l)pyrene and benzo(j)fluoranthene) only dibenz(a,h)anthracene was not detected. The total concentrations of PAHs varied by a factor of more than 100-fold, from 0.22 (Loligo gahi) to 60.9 μg/kg ww (Loligo reynaudii). Intra- and inter-specific variability of PAH levels was statistically assessed. Nine carcinogenic (probable/possible) PAHs accounted for 1% (L. reynaudii) to 26% (Loligo opalescens) of the total PAHs content being the main contributors naphthalene (in Loligo duvaucelii, L. reynaudii and Loligo vulgaris species), chrysene (in L. opalescens) and indeno(1,2,3-cd)pyrene (in L. gahi). PAHs source analysis indicated that four of the five zones of capture of the different squid species are significantly affected by both petrogenic and pyrolytic sources. Assessment of the target carcinogenic risks, established by the US EPA, suggested that L. gahi (Atlantic Ocean) and L. opalescens (from Pacific Ocean) may pose additional risks for consumers, if not eaten in moderation, derived from benzo(a)pyrene ingestion.

  6. Y1Ba2Cu3O(7-delta) thin film dc SQUIDs (superconducting quantum interference device)

    Science.gov (United States)

    Racah, Daniel

    1991-03-01

    Direct current superconducting quantum interferometers (SQUIDs) based on HTSC thin films have been measured and characterized. The thin films used were of different quality: (1) Granular films on Sapphire substrates, prepared either by e-gun evaporation, by laser ablation or by MOCVD (metal oxide chemical vapor deposition), (2) Epitaxial films on MgO substrates. Modulations of the voltage on the SQUIDs as a function of the applied flux have been observed in a wide range of temperatures. The nature of the modulation was found to be strongly dependent on the morphology of the film and on its critical current. The SQUIDs based on granular films were relatively noisy, hysteretic and with a complicated V-phi shape. Those devices based on low quality (lowIc) granular films could be measured only at low temperatures (much lower than 77 K). While those of higher quality (granular films with high Ic) could be measured near to the superconductive transition. The SQUID based on high quality epitaxial film was measured near Tc and showed an anomalous, time dependent behavior.

  7. Range expansion of the jumbo squid in the NE Pacific: δ15N decrypts multiple origins, migration and habitat use.

    Science.gov (United States)

    Ruiz-Cooley, Rocio I; Ballance, Lisa T; McCarthy, Matthew D

    2013-01-01

    Coincident with climate shifts and anthropogenic perturbations, the highly voracious jumbo squid Dosidicus gigas reached unprecedented northern latitudes along the NE Pacific margin post 1997-98. The physical or biological drivers of this expansion, as well as its ecological consequences remain unknown. Here, novel analysis from both bulk tissues and individual amino acids (Phenylalanine; Phe and Glutamic acid; Glu) in both gladii and muscle of D. gigas captured in the Northern California Current System (NCCS) documents for the first time multiple geographic origins and migration. Phe δ(15)N values, a proxy for habitat baseline δ(15)N values, confirm at least three different geographic origins that were initially detected by highly variable bulk δ(15)N values in gladii for squid at small sizes (60 cm) converged, indicating feeding in a common ecosystem. The strong latitudinal gradient in Phe δ(15)N values from composite muscle samples further confirmed residency at a point in time for large squid in the NCCS. These results contrast with previous ideas, and indicate that small squid are highly migratory, move into the NCCS from two or more distinct geographic origins, and use this ecosystem mainly for feeding. These results represent the first direct information on the origins, immigration and habitat use of this key "invasive" predator in the NCCS, with wide implications for understanding both the mechanisms of periodic D. gigas population range expansions, and effects on ecosystem trophic structure.

  8. Age, maturation, and population structure of the Humboldt squid Dosidicus gigas off the Peruvian Exclusive Economic Zones

    Institute of Scientific and Technical Information of China (English)

    LIU Bilin; CHEN Xinjun; CHEN Yong; TIAN Siquan; LI Jianhua; FANG Zhou; YANG Mingxia

    2013-01-01

    Age,maturation and population structure of the Humboldt squid Dosidicus gigas were studied based on random sampling of the Chinese jigging fishery off the Peruvian Exclusive Economic Zones (EEZ) during 2008-2010.Estimated ages ranged from 144 to 633 days,confirming that the squid is a short-lived species with longevity no longer than 2 years.Occurrence of mature females and hatching in each month indicated that Humboldt squid spawned year-round.Back-calculated hatching dates for the samples were from January 22nd,2008 to April 22nd,2010 with a peak between January and March.Two size-based and two hatching date-based populations could be defined from mantle length (ML) at maturity and back-calculated hatching dates,respectively.Females matured at a larger size than males,and there was a significant difference in ML at maturity between the two hatching groups (P<0.05).The waters adjacent to 11°S off the Peruvian EEZ may be a potential spawning ground.This study shows the complexity of the population structure and large variability in key life history parameters in the Humboldt squid off the Peruvian EEZ,which should be considered in the assessment and management of this important resource.

  9. Chromogenic behaviors of the Humboldt squid (Dosidicus gigas) studied in situ with an animal-borne video package.

    Science.gov (United States)

    Rosen, Hannah; Gilly, William; Bell, Lauren; Abernathy, Kyler; Marshall, Greg

    2015-01-15

    Dosidicus gigas (Humboldt or jumbo flying squid) is an economically and ecologically influential species, yet little is known about its natural behaviors because of difficulties in studying this active predator in its oceanic environment. By using an animal-borne video package, National Geographic's Crittercam, we were able to observe natural behaviors in free-swimming D. gigas in the Gulf of California with a focus on color-generating (chromogenic) behaviors. We documented two dynamic displays without artificial lighting at depths of up to 70 m. One dynamic pattern, termed 'flashing' is characterized by a global oscillation (2-4 Hz) of body color between white and red. Flashing was almost always observed when other squid were visible in the video frame, and this behavior presumably represents intraspecific signaling. Amplitude and frequency of flashing can be modulated, and the phase relationship with another squid can also be rapidly altered. Another dynamic display termed 'flickering' was observed whenever flashing was not occurring. This behavior is characterized by irregular wave-like activity in neighboring patches of chromatophores, and the resulting patterns mimic reflections of down-welled light in the water column, suggesting that this behavior may provide a dynamic type of camouflage. Rapid and global pauses in flickering, often before a flashing episode, indicate that flickering is under inhibitory neural control. Although flashing and flickering have not been described in other squid, functional similarities are evident with other species.

  10. Range expansion of the jumbo squid in the NE Pacific: δ15N decrypts multiple origins, migration and habitat use.

    Directory of Open Access Journals (Sweden)

    Rocio I Ruiz-Cooley

    Full Text Available Coincident with climate shifts and anthropogenic perturbations, the highly voracious jumbo squid Dosidicus gigas reached unprecedented northern latitudes along the NE Pacific margin post 1997-98. The physical or biological drivers of this expansion, as well as its ecological consequences remain unknown. Here, novel analysis from both bulk tissues and individual amino acids (Phenylalanine; Phe and Glutamic acid; Glu in both gladii and muscle of D. gigas captured in the Northern California Current System (NCCS documents for the first time multiple geographic origins and migration. Phe δ(15N values, a proxy for habitat baseline δ(15N values, confirm at least three different geographic origins that were initially detected by highly variable bulk δ(15N values in gladii for squid at small sizes (60 cm converged, indicating feeding in a common ecosystem. The strong latitudinal gradient in Phe δ(15N values from composite muscle samples further confirmed residency at a point in time for large squid in the NCCS. These results contrast with previous ideas, and indicate that small squid are highly migratory, move into the NCCS from two or more distinct geographic origins, and use this ecosystem mainly for feeding. These results represent the first direct information on the origins, immigration and habitat use of this key "invasive" predator in the NCCS, with wide implications for understanding both the mechanisms of periodic D. gigas population range expansions, and effects on ecosystem trophic structure.

  11. Age, maturation, and population structure of the Humboldt squid Dosidicus gigas off the Peruvian Exclusive Economic Zones

    Science.gov (United States)

    Liu, Bilin; Chen, Xinjun; Chen, Yong; Tian, Siquan; Li, Jianhua; Fang, Zhou; Yang, Mingxia

    2013-01-01

    Age, maturation and population structure of the Humboldt squid Dosidicus gigas were studied based on random sampling of the Chinese jigging fishery off the Peruvian Exclusive Economic Zones (EEZ) during 2008-2010. Estimated ages ranged from 144 to 633 days, confirming that the squid is a short-lived species with longevity no longer than 2 years. Occurrence of mature females and hatching in each month indicated that Humboldt squid spawned year-round. Back-calculated hatching dates for the samples were from January 22nd, 2008 to April 22nd, 2010 with a peak between January and March. Two size-based and two hatching date-based populations could be defined from mantle length (ML) at maturity and back-calculated hatching dates, respectively. Females matured at a larger size than males, and there was a significant difference in ML at maturity between the two hatching groups ( P <0.05). The waters adjacent to 11°S off the Peruvian EEZ may be a potential spawning ground. This study shows the complexity of the population structure and large variability in key life history parameters in the Humboldt squid off the Peruvian EEZ, which should be considered in the assessment and management of this important resource.

  12. Construction and Tests of a High-Tc SQUID-Based Heart Scanner Cooled by Small Stirling Cryocoolers

    NARCIS (Netherlands)

    Blom, C.J.H.A.; Brake, ter H.J.M.; Holland, H.J.; Rijpma, A.P.; Rogalla, H.; Ross, R.G.

    1999-01-01

    A heart scanner that can be equipped with up to 25 high-Tc SQUID magnetometers was designed at the University of Twente. In this design the mechanical cooler interference is reduced by operating two coolers in counterphase. The magnetic cooler interference diminished by positioning the coolers and t

  13. Projected near-future CO2 levels increase activity and alter defensive behaviours in the tropical squid Idiosepius pygmaeus

    Directory of Open Access Journals (Sweden)

    Blake L. Spady

    2014-10-01

    Full Text Available Carbon dioxide (CO2 levels projected to occur in the oceans by the end of this century cause a range of behavioural effects in fish, but whether other highly active marine organisms, such as cephalopods, are similarly affected is unknown. We tested the effects of projected future CO2 levels (626 and 956 µatm on the behaviour of male two-toned pygmy squid, Idiosepius pygmaeus. Exposure to elevated CO2 increased the number of active individuals by 19–25% and increased movement (number of line-crosses by nearly 3 times compared to squid at present-day CO2. Squid vigilance and defensive behaviours were also altered by elevated CO2 with >80% of individuals choosing jet escape responses over defensive arm postures in response to a visual startle stimulus, compared with 50% choosing jet escape responses at control CO2. In addition, more escape responses were chosen over threat behaviours in body pattern displays at elevated CO2 and individuals were more than twice as likely to use ink as a defence strategy at 956 µatm CO2, compared with controls. Increased activity could lead to adverse effects on energy budgets as well as increasing visibility to predators. A tendency to respond to a stimulus with escape behaviours could increase survival, but may also be energetically costly and could potentially lead to more chases by predators compared with individuals that use defensive postures. These results demonstrate that projected future ocean acidification affects the behaviours of a tropical squid species.

  14. Dynamics of d-wave YBa{sub 2}Cu{sub 3}O{sub 7-x} dc SQUIDs

    Energy Technology Data Exchange (ETDEWEB)

    Bauch, T [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden); Cedergren, K [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden); Johansson, J [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden); Rotoli, G [Dipartimento di Ingeneria Meccanica, Energetica e Gestionale, Universita of L' Aquila, Localita Moneluco, L' Aquila (Italy); Tafuri, F [Dipartimento Ingeneria dell' Informatione, INFM, Seconda Universita di Napoli, Aversa (Italy); Lombardi, F [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden)

    2007-02-15

    The predominant d-wave pairing symmetry in high temperature superconductors leads to an unconventional current-phase relation in Josephson junctions. This circumstance may induce new effects in the dynamics of dc SQUIDs. In this contribution we report on the measurements of the dependence of the SQUID Josephson current on the external magnetic field taken at very low temperatures, down to 20 mK. Different grain boundaries have been fabricated by using the biepitaxial and the bicrystal technique. Some of the effects which are induced by a nonsinusoidal current-phase relation can be clearly identified in the dynamics of the SQUIDs. The experimental data are also compared with theoretical simulations taking into account the inductance of the loop. The data show that, in specific conditions, a non-negligible inductance of the loop can induce effects similar to an unconventional current-phase relation, with a pronounced second harmonic sin(2{psi}) term. This fact has to be taken into account when designing d-wave SQUIDs for quantum circuitry.

  15. An ethogram of body patterning behavior in the biomedically and commercially valuable squid Loligo pealei off Cape Cod, Massachusetts.

    Science.gov (United States)

    Hanlon, R T; Maxwell, M R; Shashar, N; Loew, E R; Boyle, K L

    1999-08-01

    Squids have a wide repertoire of body patterns; these patterns contain visual signals assembled from a highly diverse inventory of chromatic, postural, and locomotor components. The chromatic components reflect the activity of dermal chromatophore organs that, like the postural and locomotor muscles, are controlled directly from the central nervous system. Because a thorough knowledge of body patterns is fundamental to an understanding of squid behavior, we have compiled and described an ethogram (a catalog of body patterns and associated behaviors) for Loligo pealei. Observations of this species were made over a period of three years (> or = 440 h) and under a variety of behavioral circumstances. The natural behavior of the squid was filmed on spawning grounds off Cape Cod (northwestern Atlantic), and behavioral trials in the laboratory were run in large tanks. The body pattern components--34 chromatic (including 4 polarization components), 5 postural, and 12 locomotor--are each described in detail. Eleven of the most common body patterns are also described. Four of them are chronic, or long-lasting, patterns for crypsis; an example is Banded Bottom Sitting, which produces disruptive coloration against the substrate. The remaining seven patterns are acute; they are mostly used in intraspecific communication among spawning squids. Two of these acute patterns--Lateral Display and Mate Guarding Pattern--are used during agonistic bouts and mate guarding; they are visually bright and conspicuous, which may subject the squids to predation; but we hypothesize that schooling and diurnal activity may offset the disadvantage presented by increased visibility to predators. The rapid changeability and the diversity of body patterns used for crypsis and communication are discussed in the context of the behavioral ecology of this species.

  16. Scanning SQUID microscope system for geological samples: system integration and initial evaluation

    Science.gov (United States)

    Oda, Hirokuni; Kawai, Jun; Miyamoto, Masakazu; Miyagi, Isoji; Sato, Masahiko; Noguchi, Atsushi; Yamamoto, Yuhji; Fujihira, Jun-ichi; Natsuhara, Nobuyoshi; Aramaki, Yoshiyasu; Masuda, Takashige; Xuan, Chuang

    2016-11-01

    We have developed a high-resolution scanning superconducting quantum interference device (SQUID) microscope for imaging the magnetic field of geological samples at room temperature. In this paper, we provide details about the scanning SQUID microscope system, including the magnetically shielded box (MSB), the XYZ stage, data acquisition by the system, and initial evaluation of the system. The background noise in a two-layered PC permalloy MSB is approximately 40-50 pT. The long-term drift of the system is approximately ≥1 nT, which can be reduced by drift correction for each measurement line. The stroke of the XYZ stage is 100 mm × 100 mm with an accuracy of 10 µm, which was confirmed by laser interferometry. A SQUID chip has a pick-up area of 200 μm × 200 μm with an inner hole of 30 μm × 30 μm. The sensitivity is 722.6 nT/V. The flux-locked loop has four gains, i.e., ×1, ×10, ×100, and ×500. An analog-to-digital converter allows analog voltage input in the range of about ±7.5 V in 0.6-mV steps. The maximum dynamic range is approximately ±5400 nT, and the minimum digitizable magnetic field is 0.9 pT. The sensor-to-sample distance is measured with a precision line current, which gives the minimum of 200 µm. Considering the size of pick-up coil, sensor-to-sample distance, and the accuracy of XYZ stage, spacial resolution of the system is 200 µm. We developed the software used to measure the sensor-to-sample distance with line scan data, and the software to acquire data and control the XYZ stage for scanning. We also demonstrate the registration of the magnetic image relative to the optical image by using a pair of point sources placed on the corners of a sample holder outside of a thin section placed in the middle of the sample holder. Considering the minimum noise estimate of the current system, the theoretical detection limit of a single magnetic dipole is 1 × 10-14 Am2. The new instrument is a powerful tool that could be used in various

  17. SQUID-magnetometry on Fe monolayers on GaAs(001) in UHV

    Energy Technology Data Exchange (ETDEWEB)

    Kebe, T.

    2006-12-11

    This thesis deals with the characterization of the growth and of the magnetic properties of ultrathin Fe films on GaAs(001). In particular, a scanning SQUID (superconducting quantum interference device) magnetometer was used in ultrahigh vacuum (UHV), whose performance has been improved within the scope of this thesis. By probing the magnetic stray field of a magnetized film, the absolute remanent magnetization can be determined with submonolayer sensitivity. In the context of this thesis the magnetic stray field has been calculated analytically. The combined use of SQUID and ferromagnetic resonance (FMR) on the same film in UHV allows for the independent determination of the magnetization and the magnetic anisotropy constants as a function of temperature, film thickness, topography of the substrate and oxygen exposure. The results of this thesis are: 1. The thickness dependent remanent magnetization from 2 to 20 monolayer (ML) Fe on GaAs(001) without cap layer was measured as a function of temperature. 2. The continuous in-plane reorientation of the magnetization (from [1 1 0] to [1 0 0]) of Fe films with increasing film thickness was observed using the scanning SQUID technique and showed good agreement with FMR measurements. 3. The influence of controlled oxygen exposure on the remanent magnetization and the magnetic anisotropy constants of 5 to 16 ML Fe was investigated. A faster reduction of the magnetization is found for the thinner Fe films when the volume of the Fe oxide is taken into consideration. At low oxygen exposure (<10 Langmuir), the perpendicular uniaxial anisotropy constant K{sub 2} {sub perpendicular} {sub to} is reduced by about 40% whereas other anisotropy contributions remain virtually unchanged. In addition, structural investigations using IV-LEED during the oxygen exposure were carried out. 4. An 8.6 ML Fe/GaAs(001) film which was exposed to 25000 L O{sub 2} exhibits a spontaneous magnetization perpendicular to the film plane at low

  18. A modular, extendible and field-tolerant multichannel vector magnetometer based on current sensor SQUIDs

    Science.gov (United States)

    Storm, J.-H.; Drung, D.; Burghoff, M.; Körber, R.

    2016-09-01

    We present the prototype module of our extendible and robust multichannel SQUID magnetometer system. A large multi-module arrangement can be implemented by using up to 7 modules. The system is intended for high-precision measurements of biomagnetism and spin precession. Further demanding applications are magnetorelaxometry and ultra-low-field nuclear magnetic resonance (ULF NMR), where pulsed magnetic fields of up to 100 mT are typically applied. The system is operated inside the Berlin magnetically shielded room (BMSR-2) and equipped with 18 magnetometers consisting of niobium (Nb) wire-wound pick-up coils. A total of 16 small pick-up coils with 17.1 mm diameter form a regular grid with individual channels arranged to ensure system sensitivity covers all three orthogonal spatial directions. Two large hexagonal pick-up coils with an equivalent diameter of 74.5 mm sensitive in z-direction surround the grid at two different heights and are suitable for the detection of deep sources. Each pick-up coil is connected to the input of a thin-film Nb SQUID current sensor via a detachable superconducting contact. The SQUIDs are equipped with integrated input current limiters. Feedback into the pick-up coils is employed to minimise crosstalk between channels. The current sensor chip package includes a superconducting shield of Nb. The field distortion of the prototype and a multi-module arrangement was analysed by numerical simulation. The measured noise of the small magnetometers was between 0.6 and 1.5 fT {{Hz}}-1/2, and well below 1 fT {{Hz}}-1/2 for the large ones. Using a software gradiometer, we achieved a minimum noise level of 0.54 fT {{Hz}}-1/2. We performed ULF NMR experiments, verifying the system’s robustness against pulsed fields, and magnetoencephalographgy (MEG) on somatosensory evoked neuronal activity. The low noise performance of our 18-channel prototype enabled the detection of high-frequency components at around 1 kHz by MEG.

  19. High-Tc planar SQUID gradiometer for eddy current non-destructive evaluation

    Institute of Scientific and Technical Information of China (English)

    Zhang Ming-Jian; Lang Pei-Lin; Peng Zhi-Hui; Chen Ying-Fei; Chen Ke; Zheng Dong-Ning

    2006-01-01

    This paper reports the fabrication and test of a high-Tc SQUID planar gradiometer which is patterned from YBCO thin film deposited on a SrTiOs bicrystal substrate. The measurement of noise spectrum at 77K shows that the white noise at 200 Hz is about 1×10-4Φ0/Hz. The minimal magnetic gradient is measured and the results suggest that the minimal magnetic gradient is 94 pT/m. The planar gradiometer is used in non-destructive evaluation (NDE) experiments to detect the artifacts in conducting aluminium plates by performing eddy current testing in an unshielded environment. The effect of the exciting coil dimension on the NDE results is investigated. By mapping out the induced field distribution, flaws about 10mm below the plate surface can be clearly identified.

  20. Infiltration of chitin by protein coacervates defines the squid beak mechanical gradient.

    Science.gov (United States)

    Tan, YerPeng; Hoon, Shawn; Guerette, Paul A; Wei, Wei; Ghadban, Ali; Hao, Cai; Miserez, Ali; Waite, J Herbert

    2015-07-01

    The beak of the jumbo squid Dosidicus gigas is a fascinating example of how seamlessly nature builds with mechanically mismatched materials. A 200-fold stiffness gradient begins in the hydrated chitin of the soft beak base and gradually increases to maximum stiffness in the dehydrated distal rostrum. Here, we combined RNA-Seq and proteomics to show that the beak contains two protein families. One family consists of chitin-binding proteins (DgCBPs) that physically join chitin chains, whereas the other family comprises highly modular histidine-rich proteins (DgHBPs). We propose that DgHBPs play multiple key roles during beak bioprocessing, first by forming concentrated coacervate solutions that diffuse into the DgCBP-chitin scaffold, and second by inducing crosslinking via an abundant GHG sequence motif. These processes generate spatially controlled desolvation, resulting in the impressive biomechanical gradient. Our findings provide novel molecular-scale strategies for designing functional gradient materials.

  1. FEM enhanced signal processing approach for pattern recognition in the SQUID based NDE system

    Energy Technology Data Exchange (ETDEWEB)

    Sarreshtedari, F; Jahed, N M S; Hosseni, N; Pourhashemi, A; Fardmanesh, M [Department of Electrical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Banzet, Marko; Schubert, Juergen, E-mail: fardmanesh@sharif.ed [Forschungszentrum Juelich, Institute of Bio and Nanosystems, 52425 Juelich (Germany)

    2010-06-01

    An efficient Non-Destructive Evaluation algorithm has been developed in order to extract the required information for pattern recognition of defects in the conductive samples. Using high-Tc gradiometer RF-SQUIDs in unshielded environments and incorporating an automated two dimensional non-magnetic scanning robot, samples with different intentional defects have been tested. We have used a developed noise cancellation approach for the improvement of the effectiveness of the used inverse-problem technique. In this approach we have used a well examined Finite Element Method (FEM) to apply a noise reduction filtering on the obtained raw magnetic image data before incorporating the signal processing analysis. By applying this noise cancellation filter and incorporating three different signal processing algorithms and comparing the results of the predicted images by the pattern of the intentionally made defects, we have investigated the ability of these methods for pattern recognition of unknown defects.

  2. SQUID based cryogenic current comparator for measurements of the dark current of superconducting cavities

    Energy Technology Data Exchange (ETDEWEB)

    Vodel, W.; Nietzsche, S.; Neubert, R.; Nawrodt, R. [Friedrich Schiller Univ. Jena (Germany); Peters, A. [GSI Darmstadt (Germany); Knaack, K.; Wendt, M.; Wittenburg, K. [DESY Hamburg (Germany)

    2005-07-01

    The linear accelerator technology, based on super-conducting L-band (1.3 GHz) is currently under study at DESY (Hamburg, Germany). The two 10 km long main Linacs will be equipped with a total of nearly 20.000 cavities. The dark current due to the emission of electrons in these high gradient field super-conducting cavities is an unwanted particle source. A newly high performance SQUID based measurement system for detecting dark currents is proposed. It makes use of the Cryogenic Current Comparator principle and senses dark currents in the pA range with a measurement bandwidth of up to 70 kHz. The use of a cryogenic current comparator as dark current sensor has some important advantages: -) the measurement of the absolute value of the dark current, -) the non-dependence on the electron trajectories, -) the accurate absolute calibration with an additional wire loop, and -) extremely high resolution.

  3. Customizing Properties of β-Chitin in Squid Pen (Gladius by Chemical Treatments

    Directory of Open Access Journals (Sweden)

    Alessandro Ianiro

    2014-12-01

    Full Text Available The squid pen (gladius from the Loligo vulgaris was used for preparation of β-chitin materials characterized by different chemical, micro- and nano-structural properties that preserved, almost completely the macrostructural and the mechanical ones. The β-chitin materials obtained by alkaline treatment showed porosity, wettability and swelling that are a function of the duration of the treatment. Microscopic, spectroscopic and synchrotron X-ray diffraction techniques showed that the chemical environment of the N-acetyl groups of the β-chitin chains changes after the thermal alkaline treatment. As a consequence, the crystalline packing of the β-chitin is modified, due to the intercalation of water molecules between β-chitin sheets. Potential applications of these β-chitin materials range from the nanotechnology to the regenerative medicine. The use of gladii, which are waste products of the fishing industry, has also important environmental implications.

  4. Neuromagnetic recordings of the human peripheral nerve with planar SQUID gradiometers

    Energy Technology Data Exchange (ETDEWEB)

    Lang, G.; Maas, P.; Pegrum, C.M.; Donaldson, G.B. [Department of Physics and Applied Physics, University of Strathclyde, 107 Rottenrow, Glasgow G4 0NG (United Kingdom); Shahani, U.; Weir, A.I. [Wellcome Biomagnetism Unit, Southern General Hospital, 1345 Govan Road, Glasgow G51 4TF (United Kingdom)

    1998-08-01

    Magnetic fields produced by a travelling volley in the human ulnar nerve have been successfully measured in a lightly shielded environment. Recordings of the tangential component of the magnetic field were made using a planar second-order gradiometer integrated with a first-order gradiometric superconducting quantum interference device (SQUID). Devices were fabricated in our clean-room facility at the University of Strathclyde and measurements taken in an eddy-current shielded room at the Wellcome Biomagnetism Unit. We use no additional shielding and no electronic differencing or field-nulling techniques. Evoked magnetic fields of 60 fT peak-to-peak were obtained after 1536 averages but they could be seen easily as early as 512 averages. Measurements were made over four points above the ulnar nerve on the upper arm and from these the conduction velocity was calculated as 60 m s{sup -1}. (author)

  5. DC current distribution mapping system of the solar panels using a HTS-SQUID gradiometer

    Science.gov (United States)

    Miyazaki, Shingo; Kasuya, Syohei; Mawardi Saari, Mohd; Sakai, Kenji; Kiwa, Toshihiko; Tsukamoto, Akira; Adachi, Seiji; Tanabe, Keiichi; Tsukada, Keiji

    2014-05-01

    Solar panels are expected to play a major role as a source of sustainable energy. In order to evaluate solar panels, non-destructive tests, such as defect inspections and response property evaluations, are necessary. We developed a DC current distribution mapping system of the solar panels using a High Critical Temperature Superconductor Superconducting Quantum Interference Device (HTS-SQUID) gradiometer with ramp edge type Josephson junctions. Two independent components of the magnetic fields perpendicular to the panel surface (∂Bz/∂x, ∂Bz/∂y) were detected. The direct current of the solar panel is visualized by calculating the composition of the two signal components, the phase angle, and mapping the DC current vector. The developed system can evaluate the uniformity of DC current distributions precisely and may be applicable for defect detection of solar panels.

  6. Enhanced magnetic moment of ultrathin Co films measured by in situ electrodeposition in a SQUID

    Science.gov (United States)

    Topolovec, Stefan; Krenn, Heinz; Würschum, Roland

    2016-01-01

    A special electrochemical cell enabling in situ electrodeposition in a SQUID magnetometer is applied to study the magnetic moment of ultrathin Co films during growth on an Au(111) substrate. The in situ electrodeposition approach allows a total elimination of the magnetic background signal of the substrate, thus the magnetic moment which arises exclusively from the deposited Co film could be measured with monolayer sensitivity. The average thickness of the deposited Co films dav as determined from the transferred charge can be adjusted easily by varying the parameters of the electrodeposition. Hence, the magnetic moment of Co thin films could be determined in absolute terms as a function of the film thickness dav. For the first few atomic layers an enhancement of the magnetic moment per Co atom compared to the bulk could be observed, which increases steadily with lowering dav, reaching up to 40%.

  7. Multi-Channel SQUID System for MEG and Ultra-Low-Field MRI

    CERN Document Server

    Zotev, V S; Volegov, P L; Sandin, H J; Espy, M A; Mosher, J C; Urbaitis, A V; Newman, S G; Zotev, Vadim S.; Matlachov, Andrei N.; Volegov, Petr L.; Sandin, Henrik J.; Espy, Michelle A.; Mosher, John C.; Urbaitis, Algis V.; Newman, Shaun G.; Jr, Robert H. Kraus

    2007-01-01

    A seven-channel system capable of performing both magnetoencephalography (MEG) and ultra-low-field magnetic resonance imaging (ULF MRI) is described. The system consists of seven second-order SQUID gradiometers with 37 mm diameter and 60 mm baseline, having magnetic field resolution of 1.2-2.8 fT/rtHz. It also includes four sets of coils for 2-D Fourier imaging with pre-polarization. The system's MEG performance was demonstrated by measurements of auditory evoked response. The system was also used to obtain a multi-channel 2-D image of a whole human hand at the measurement field of 46 microtesla with 3 by 3 mm resolution.

  8. Concentrations of biogenic amines in fish, squid and octopus and their changes during storage.

    Science.gov (United States)

    Hu, Yue; Huang, Zhiyong; Li, Jian; Yang, Hong

    2012-12-15

    The concentrations of seven biogenic amines (BA) were simultaneously determined in 74 samples of fish, squid and octopus, by the method of HPLC coupled with pre-column derivatisation. The relationship between the formation of BA in aquatic products and the growth of microbial flora during storage was also investigated. Results showed that putrescine, cadaverine, histamine and tyramine were the dominant BA in the studied samples, but the concentrations of histamine and tyramine were mostly less than 50 and 100 mgkg(-1), respectively. Freezing can effectively prevent the formation of BA, but the levels of putrescine, cadaverine, histamine and tyramine significantly increased (poctopus strongly and positively correlated with the formation of amines (such as putrescine, cadaverine, histamine and tyramine) during storage, except for histamine in octopus.

  9. Why small males have big sperm: dimorphic squid sperm linked to alternative mating behaviours

    Directory of Open Access Journals (Sweden)

    Shiba Kogiku

    2011-08-01

    Full Text Available Abstract Background Sperm cells are the target of strong sexual selection that may drive changes in sperm structure and function to maximize fertilisation success. Sperm evolution is regarded to be one of the major consequences of sperm competition in polyandrous species, however it can also be driven by adaptation to the environmental conditions at the site of fertilization. Strong stabilizing selection limits intra-specific variation, and therefore polymorphism, among fertile sperm (eusperm. Here we analyzed reproductive morphology differences among males employing characteristic alternative mating behaviours, and so potentially different conditions of sperm competition and fertilization environment, in the squid Loligo bleekeri. Results Large consort males transfer smaller (average total length = 73 μm sperm to a female's internal sperm storage location, inside the oviduct; whereas small sneaker males transfer larger (99 μm sperm to an external location around the seminal receptacle near the mouth. No significant difference in swimming speed was observed between consort and sneaker sperm. Furthermore, sperm precedence in the seminal receptacle was not biased toward longer sperm, suggesting no evidence for large sperm being favoured in competition for space in the sperm storage organ among sneaker males. Conclusions Here we report the first case, in the squid Loligo bleekeri, where distinctly dimorphic eusperm are produced by different sized males that employ alternative mating behaviours. Our results found no evidence that the distinct sperm dimorphism was driven by between- and within-tactic sperm competition. We propose that presence of alternative fertilization environments with distinct characteristics (i.e. internal or external, whether or not in combination with the effects of sperm competition, can drive the disruptive evolution of sperm size.

  10. A numerical and experimental investigation of planar asymmetric SQUID gradiometer characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Klein, U.; Walker, M.E.; Cochran, A.; Hutson, D.; Lang, G.; Weston, R.G.; Pegrum, C.M. [University of Strathclyde, Department of Physics and Applied Physics, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG (United Kingdom)

    1996-04-01

    A low-cost, high-performance magnetic field sensor for applications such as biomagnetism and nondestructive evaluation can be fabricated by integrating a superconducting quantum interference device (SQUID) and a gradiometer on a single chip. Conventionally, the gradiometric pick-up loop would have a rectangular outline divided symmetrically about the midpoint of its length so that its spatial response was also symmetrical. However, it is also possible to divide the same outline asymmetrically, maintaining the field rejection order of the gradiometer by adding an extra crossover. The spatial response of this arrangement will also be asymmetric, which may be exploited to reduce the effects of the nearby SQUID as a magnetic anomaly or to enhance the sensitivity of the device to magnetic sources at a particular distance. The techniques to calculate the crossover positions are well established. Here we outline how different designs may be evaluated theoretically and report on first experimental results for three simple designs. Several devices have been fabricated using a well established Nb/Al-Al{sub 2}O{sub 3}/Nb trilayer process with high yields. The measurement of the spatial response of an asymmetric first-order gradiometer shows the expected magnetometer characteristics for a magnetic dipole source in the near field and first-order gradiometric characteristics for a far-field source. The balance of the integrated gradiometer appears to be better than one part in 10{sup 4}, and the magnetic field gradient sensitivity has been measured to be 100 fT cm{sup -1} Hz{sup -1/2}. (author)

  11. Turning performance in squid and cuttlefish: unique dual-mode, muscular hydrostatic systems.

    Science.gov (United States)

    Jastrebsky, Rachel A; Bartol, Ian K; Krueger, Paul S

    2016-05-01

    Although steady swimming has received considerable attention in prior studies, unsteady swimming movements represent a larger portion of many aquatic animals' locomotive repertoire and have not been examined extensively. Squids and cuttlefishes are cephalopods with unique muscular hydrostat-driven, dual-mode propulsive systems involving paired fins and a pulsed jet. These animals exhibit a wide range of swimming behavior, but turning performance has not been examined quantitatively. Brief squid, Lolliguncula brevis, and dwarf cuttlefish, Sepia bandensis, were filmed during turns using high-speed cameras. Kinematic features were tracked, including the length-specific radius of the turn (R/L), a measure of maneuverability, and angular velocity (ω), a measure of agility. Both L. brevis and S. bandensis demonstrated high maneuverability, with (R/L)min values of 3.4×10(-3)±5.9×10(-4) and 1.2×10(-3)±4.7×10(-4) (mean±s.e.m.), respectively, which are the lowest measures of R/L reported for any aquatic taxa. Lolliguncula brevis exhibited higher agility than S. bandensis (ωa,max=725.8 versus 485.0 deg s(-1)), and both cephalopods have intermediate agility when compared with flexible-bodied and rigid-bodied nekton of similar size, reflecting their hybrid body architecture. In L. brevis, jet flows were the principal driver of angular velocity. Asymmetric fin motions played a reduced role, and arm wrapping increased turning performance to varying degrees depending on the species. This study indicates that coordination between the jet and fins is important for turning performance, with L. brevis achieving faster turns than S. bandensis and S. bandensis achieving tighter, more controlled turns than L. brevis.

  12. Properties of sodium and potassium channels of the squid giant axon far below 0 degrees C.

    Science.gov (United States)

    Kukita, F

    1982-01-01

    Squid giant axon could be excited in concentrated glycerol solutions containing normal concentrations of electrolytes, when osmolalities of solutions inside and outside the axon were matched. These glycerol solutions did not freeze at the temperature as low as -19 degrees C. The nerve excitation in these solutions were observed at this low temperature. The excitation process at this low temperature was slowed down and time constants of the excitation kinetics were several hundredfold larger than those in normal seawater at 10 degrees C, under which temperature the squid habituated. The temperature coefficients for the electrophysiological membrane parameters under this condition were larger than those in normal seawater above 0 degrees C. The Q10 value for the conduction velocity was 2.0 and that of the duration of the action potential was around 8.5. The time course of the membrane currents was also slowed with the Q10 value of around 5 and the magnitude decreased with the Q10 value of around 2 as the temperature was lowered. The Q10 values for the kinetics of the on process of the Na-channel were around 4.5 and were almost the same as those of the off process of the Na-channel in the wide range of the temperature below 0 degrees C. The Q10 value of the on process of K-channel was around 6.5 and was larger than those for Na-channel. The Q10 values increased gradually as the temperature was lowered.

  13. Combined climate- and prey-mediated range expansion of Humboldt squid (Dosidicus gigas), a large marine predator in the California Current System.

    Science.gov (United States)

    Stewart, Julia S; Hazen, Elliott L; Bograd, Steven J; Byrnes, Jarrett E K; Foley, David G; Gilly, William F; Robison, Bruce H; Field, John C

    2014-06-01

    Climate-driven range shifts are ongoing in pelagic marine environments, and ecosystems must respond to combined effects of altered species distributions and environmental drivers. Hypoxic oxygen minimum zones (OMZs) in midwater environments are shoaling globally; this can affect distributions of species both geographically and vertically along with predator-prey dynamics. Humboldt (jumbo) squid (Dosidicus gigas) are highly migratory predators adapted to hypoxic conditions that may be deleterious to their competitors and predators. Consequently, OMZ shoaling may preferentially facilitate foraging opportunities for Humboldt squid. With two separate modeling approaches using unique, long-term data based on in situ observations of predator, prey, and environmental variables, our analyses suggest that Humboldt squid are indirectly affected by OMZ shoaling through effects on a primary food source, myctophid fishes. Our results suggest that this indirect linkage between hypoxia and foraging is an important driver of the ongoing range expansion of Humboldt squid in the northeastern Pacific Ocean.

  14. YBa{sub 2}Cu{sub 3}O{sub 7} grain boundary junction dc SQUIDs for operation in high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Konovalenko, Konstantin; Nagel, Joachim; Turad, Markus; Bailer, Matthias; Gruenzweig, Matthias; Kleiner, Reinhold; Koelle, Dieter [Physikalisches Institut, Center for Collective Quantum Phenomena, Universitaet Tuebingen (Germany)

    2009-07-01

    We investigate the suitability of dc SQUIDs for operation in high magnetic fields at 4.2 K. For this purpose, we fabricated small (micron-sized) YBa{sub 2}Cu{sub 3}O{sub 7}(YBCO) grain boundary junction dc SQUIDs on SrTiO{sub 3} bicrystals with thin film Au shunt resistors. Fabrication was done by pulsed laser deposition of YBCO films, in-situ deposition of electron-beam evaporated Au films and Ar ion milling with photolithographically defined masks. For the fabricated SQUIDs we present results on electric transport properties, measured in a four-point arrangement, and on noise properties, measured with a Nb dc SQUID amplifier.

  15. Food web and fish stock changes in central Chile: comparing the roles of jumbo squid (Dosidicus gigas) predation, the environment, and fisheries

    Science.gov (United States)

    Neira, Sergio; Arancibia, Hugo

    2013-10-01

    We analyzed recent food web and fish stock changes in the central Chile marine ecosystem, comparing the roles of jumbo squid (Dosidicus gigas) as predator, the environment, and fishing. To accomplish this we used food web modeling and the Ecopath with Ecosim software (EwE). The principal fish stocks have experienced wide decadal fluctuations in the past 30 years, including stock collapses of horse mackerel (Trachurus murphyi) and hake (Merluccius gayi), and there was a large influx of jumbo squid during the mid-2000s. We used two EwE models representing the food web off central Chile to test the hypothesis that predation by jumbo squid has been significant in explaining the dynamics of the main fishing resources and other species in the study area. Results indicate that predation by jumbo squid on fish stocks is lower than that of other predators (e.g. hake) and the fishery. Long-term fluctuations (1978-2004) in the biomass of the main fish stocks (as well as other components of the food web) seem to be related to fishing and to variation in primary production, rather than to predation by jumbo squid alone. Jumbo squid seems to play a role as predator rather than prey in the system, but its impacts are low when compared with the impacts of other predators and fishing. Therefore, we conclude that jumbo squid predation on its prey was not the primary force behind the collapse of important fish stocks off central Chile. Future efforts should be directed to better understanding factors that trigger sudden increases in jumbo squid abundance off central Chile, as well as modeling its trophic impacts.

  16. Ventilation rates and activity levels of juvenile jumbo squid under metabolic suppression in the oxygen minimum zone.

    Science.gov (United States)

    Trübenbach, Katja; Pegado, Maria R; Seibel, Brad A; Rosa, Rui

    2013-02-01

    The Humboldt (jumbo) squid, Dosidicus gigas, is a part-time resident of the permanent oxygen minimum zone (OMZ) in the Eastern Tropical Pacific and, thereby, it encounters oxygen levels below its critical oxygen partial pressure. To better understand the ventilatory mechanisms that accompany the process of metabolic suppression in these top oceanic predators, we exposed juvenile D. gigas to the oxygen levels found in the OMZ (1% O(2), 1 kPa, 10 °C) and measured metabolic rate, activity cycling patterns, swimming mode, escape jet (burst) frequency, mantle contraction frequency and strength, stroke volume and oxygen extraction efficiency. In normoxia, metabolic rate varied between 14 and 29 μmol O(2) g(-1) wet mass h(-1), depending on the level of activity. The mantle contraction frequency and strength were linearly correlated and increased significantly with activity level. Additionally, an increase in stroke volume and ventilatory volume per minute was observed, followed by a mantle hyperinflation process during high activity periods. Squid metabolic rate dropped more than 75% during exposure to hypoxia. Maximum metabolic rate was not achieved under such conditions and the metabolic scope was significantly decreased. Hypoxia changed the relationship between mantle contraction strength and frequency from linear to polynomial with increasing activity, indicating that, under hypoxic conditions, the jumbo squid primarily increases the strength of mantle contraction and does not regulate its frequency. Under hypoxia, jumbo squid also showed a larger inflation period (reduced contraction frequency) and decreased relaxed mantle diameter (shortened diffusion pathway), which optimize oxygen extraction efficiency (up to 82%/34%, without/with consideration of 60% potential skin respiration). Additionally, they breathe 'deeply', with more powerful contractions and enhanced stroke volume. This deep-breathing behavior allows them to display a stable ventilatory volume per

  17. Environmental pH, O2 and Capsular Effects on the Geochemical Composition of Statoliths of Embryonic Squid Doryteuthis opalescens

    Directory of Open Access Journals (Sweden)

    Michael O. Navarro

    2014-07-01

    Full Text Available Spawning market squid lay embryo capsules on the seafloor of the continental shelf of the California Current System (CCS, where ocean acidification, deoxygenation and intensified upwelling lower the pH and [O2]. Squid statolith geochemistry has been shown to reflect the squid’s environment (e.g., seawater temperature and elemental concentration. We used real-world environmental levels of pH and [O2] observed on squid-embryo beds to test in the laboratory whether or not squid statolith geochemistry reflects environmental pH and [O2]. We asked whether pH and [O2] levels might affect the incorporation of element ratios (B:Ca, Mg:Ca, Sr:Ca, Ba:Ca, Pb:Ca, U:Ca into squid embryonic statoliths as (1 individual elements and/or (2 multivariate elemental signatures, and consider future applications as proxies for pH and [O2] exposure. Embryo exposure to high and low pH and [O2] alone and together during development over four weeks only moderately affected elemental concentrations of the statoliths, and uranium was an important element driving these differences. Uranium:Ca was eight-times higher in statoliths exposed to low pHT (7.57–7.58 and low [O2] (79–82 µmol·kg−1 than those exposed to higher ambient pHT (7.92–7.94 and [O2] (241–243 µmol·kg−1. In a separate experiment, exposure to low pHT (7.55–7.56 or low [O2] (83–86 µmol·kg−1 yielded elevated U:Ca and Sr:Ca in the low [O2] treatment only. We found capsular effects on multiple elements in statoliths of all treatments. The multivariate elemental signatures of embryonic statoliths were distinct among capsules, but did not reflect environmental factors (pH and/or [O2]. We show that statoliths of squid embryos developing inside capsules have the potential to reflect environmental pH and [O2], but that these “signals” are generated in concert with the physiological effects of the capsules and embryos themselves.

  18. Horizontal movements, vertical-habitat utilization and diet of the jumbo squid ( Dosidicus gigas) in the Pacific Ocean off Baja California Sur, Mexico

    Science.gov (United States)

    Bazzino, Gastón; Gilly, William F.; Markaida, Unai; Salinas-Zavala, César A.; Ramos-Castillejos, Jorge

    2010-07-01

    We deployed four pop-up archival-transmitting (PAT) tags on jumbo squid ( Dosidicus gigas) collected in the Pacific Ocean off the main entrance to Magdalena Bay on the Baja California peninsula in June 2005. This is the first successful deployment of PAT tags on jumbo squid in an area outside the Gulf of California. Summary data were obtained through the ARGOS satellite system for three of the tags; the fourth tag was physically recovered. All of the tagged squid tended to remain on the shallow continental shelf for several days after tagging and then moved offshore into deeper water. Three of the four squid appeared to migrate in a general southerly direction while the fourth remained offshore of Magdalena Bay. All of the squid spent most daylight hours at depths that were associated with the hypoxic oxygen minimum layer, and at night they spent a majority of time in the upper 50 m of the water column. Stomach content analysis and tag temperature-depth data during the first days after tagging revealed that the squid were feeding on pelagic red crabs ( Pleuroncodes planipes) and several larger, neritic fishes over the continental shelf off Magdalena Bay during a seasonal nearshore upwelling. Comparison of our results with those previously collected in the Gulf of California reveal that Dosidicus gigas can vary its behavior and diet to suit local environmental conditions. This adaptability is likely to be an important factor in the ability of D. gigas to invade and colonize new areas.

  19. Description of plastic remains found in the stomach contents of the jumbo squid Dosidicus gigas landed in Ecuador during 2014.

    Science.gov (United States)

    Rosas-Luis, Rigoberto

    2016-12-15

    Squids are active and opportunistic predators that feed on a wide range of prey. Their active movements in the water column and their voracity promote a high consumption of food. In the pelagic environment off Ecuador, marine pollution is characterized by plastic debris with a mainland origin, including plastics trash of fishing gears. The objective of this work was to describe the presence of plastic remains in the stomach contents of Dosidicus gigas caught off the coast of Ecuador. Results demonstrated that 12% of the stomachs contained plastic remains. These plastics were identified as multifilament of polyethylene lines and polyvinyl chloride remains. Findings of this work could be related to an increase in the discharge of solid materials in the water column, increasing the probability to be ingested by the jumbo squid.

  20. Effect of Bovine Plasma Protein on Autolysis and Gelation of Protein Extracted from Giant Squid (Dosidicus gigas Mantle

    Directory of Open Access Journals (Sweden)

    Laura Raquel Marquez-Alvarez

    2015-01-01

    Full Text Available The effect of bovine plasma protein (BPP on the inhibition of autolytic activity and its effect on the gelling properties of a protein concentrate (PC obtained from jumbo squid (Dosidicus gigas mantle were investigated. Sols and gels were prepared from the PC by adding different amounts of BPP (0, 1, and 2%. Dynamic oscillatory measurements indicated that systems with 1% BPP had a higher elastic modulus (G′, in which hydrophobic interactions were favored. Concerning the technological and textural quality of the gels, BPP caused a greater water holding capacity (WHC, force, cohesiveness, and elasticity, probably due to improvement of the electrostatic and hydrophobic interactions during gel formation. Scanning electron microscopy (SEM allowed visualization of the formation of more rigid and ordered gels with less porosity when BPP was added. Therefore, the addition of BPP improved the gelling capacity of proteins extracted from giant squid.

  1. Description of the first Lessepsian squid migrant, Sepioteuthis lessoniana (CEPHALOPODA: Loliginidae, in the Aegean Sea (Eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    E. LEFKADITOU

    2012-12-01

    Full Text Available Loliginid squids of the Sepioteuthis lessoniana complex are widely spread in the Indo-Pacific Ocean, where they constitute a commercially important resource for neritic fisheries. Sepioteuthis lessoniana is the only Lessepsian squid migrant till now, recorded for the first time in the Mediterranean in 2002 along the Turkish Levantine coasts. Two maturing males, with mantle lengths 193 mm and 244 mm, have been recently caught near the coasts of Rhodes Island (SE Aegean, extending the species distribution northward, into Hellenic waters. Their identity was confirmed by comparison of the main body, beak characteristics and morphometric measurements with those available in the literature for this species. Suspected expansion of the Lessepsian loliginid into the Aegean Sea, due to the gradual warming of the sea, is discussed.

  2. Effect of pulsed ultrasound on the physicochemical characteristics and emulsifying properties of squid (Dosidicus gigas) mantle proteins.

    Science.gov (United States)

    Higuera-Barraza, O A; Torres-Arreola, W; Ezquerra-Brauer, J M; Cinco-Moroyoqui, F J; Rodríguez Figueroa, J C; Marquez-Ríos, E

    2017-01-12

    Food technologists are always looking to improve the functional properties of proteins. In this sense, in last years ultrasound has been used to improve some functional properties. For this reason, and considering that jumbo squid is an important fishery in northwest Mexico, the purpose of this research was to determine the effect of pulsed ultrasound on the physicochemical characteristics and emulsifying properties of squid (Dosidicus gigas) mantle proteins. Pulsed ultrasound (20kHz, 20, and 40% amplitude) was applied for 30, 60, and 90s to a protein extract prepared from giant squid mantle causing an increase (p<0.05) in surface hydrophobicity (So) from 108.4±1.4 to 239.1±2.4 after application of pulsed ultrasound at 40% of amplitude for 90s. The electrophoretic profile and the total and reactive sulfhydryl contents were not affected (p⩾0.05) by the ultrasound treatment. The emulsifying ability of the protein solution was improved (p<0.05), whereas the Emulsifier Activity Index (EAI) varied from123.67±5.52m(2)/g for the control and increased up to 217.7±3.8m(2)/g after application of the ultrasound. The Stability Emulsifier Index (EEI) was improved at 40% of amplitude by 60 and 90s. The results suggested that pulsed ultrasound used as pretreatment induced conformational changes in giant squid proteins, which improved the interfacial association between protein-oil phases, thus contributing to the improvement of their emulsifient properties.

  3. Possible link between interannual variation of neon flying squid (Ommastrephes bartramii) abundance in the North Pacific and the climate phase shift in 1998/1999

    Science.gov (United States)

    Igarashi, Hiromichi; Ichii, Taro; Sakai, Mitsuo; Ishikawa, Yoichi; Toyoda, Takahiro; Masuda, Shuhei; Sugiura, Nozomi; Mahapatra, Kedarnath; Awaji, Toshiyuki

    2017-01-01

    The relationship between interannual variation in abundance of the autumn cohort of the neon flying squid (Ommastrephes bartramii) and ocean environmental changes in the central North Pacific was examined. We focused on the change in subsurface ocean state during the 1998/1999 climate shift. Changes in catch per unit effort (CPUE) of the neon flying squid derived from long-term driftnet survey was compared to that in ocean environments related to the feeding conditions of the squid. A four-dimensional variational (4D-VAR) ocean data assimilation product was used as an accurate estimate of the dynamic state in the North Pacific. Correlation analysis indicated that the squid CPUE was highly related with the Pacific Decadal Oscillation (PDO) in winter. In January, the correlation field with the entrainment rate (ENT), the proxy for the nutrient-rich water supply entering the mixed layer, showed a good agreement with the main spawning and nursery ground of the autumn cohort (MSNGAC). The nutrient-rich water supply in the MSNGAC in early winter was mainly induced by the deepening of the mixed layer forced by surface latent heat cooling and turbulent mixing, while the basin-scale wind stress curl and the horizontal advection were less affected. These results suggest that the amount of newly supplied nutrient-rich water mass in early winter could affect the primary productivity throughout the winter and the resultant feeding conditions of the juvenile squid. We assumed that this process would determine the stock levels of the neon flying squid in the following summer. We further attempted to reconstruct the changes in neon flying squid CPUE during 1994-2006 by applying regression analysis to several parameters. The result showed that ENT, surface and subsurface temperatures, and the PDO index in February were good predictors for estimating the squid CPUE time series. In addition, the subsurface temperature in the MSNGAC in the preceding autumn was also a good predictor

  4. A cryo-amplifier working in a double loop-flux locked loop scheme for SQUID readout of TES detectors

    Science.gov (United States)

    Torrioli, Guido; Bastia, Paolo; Piro, Luigi; Macculi, Claudio; Colasanti, Luca

    2010-07-01

    In this paper we report on a novel SQUID readout scheme, called Double Loop-Flux Locked loop (DL-FLL), that we are investigating in the frame of ASI and ESA technological development contracts. This scheme is based on the realization of a cryogenic amplifier which is used in order to readout TES detectors in the Frequency Division Multiplexing technique, where high loop-gain is required up to few MHz. Loop-gain in feedback systems is, usually, limited by the propagation delay of the signals traveling in the loop because of the distance between the feedback loop elements. This problem is particularly evident in the case of SQUID systems, where the elements of the feedback loop are placed both at cryogenic and room temperature. To solve this issue we propose a low power dissipation cryo-amplifier capable to work at cryogenic temperatures so that it can be placed close to the SQUID realizing a local cryogenic loop. The adoption of the DL-FLL scheme allows to simplify considerably the cryo-amplifier which, being AC-coupled, don't require the features of a precision DC-coupled amplifier and can be made with a limited number of electronic components and with a consequent reduction of power dissipation.

  5. Effect of stimulation and hyperpolarization on non-electrolyte and sodium permeability in perfused axons of squid.

    Science.gov (United States)

    Hidalgo, C; Latorre, R

    1970-11-01

    1. The permeability for micro-injected [(3)H]ethylene glycol was measured in resting state and during stimulation at 100/sec in squid giant axons. No detectable changes during electrical activity were observed.2. The influxes of urethane, tritiated water, ethylene glycol, urea and sodium were measured in internally perfused squid axons. Ethylene glycol and urea influxes were determined simultaneously with sodium influxes. The electrical stimulation of the fibre produced an increase in the influx of sodium but did not alter the influxes of the non-electrolytes listed above.3. Experiments were done with the combined voltage clamp-perfusion technique. The influxes of ethylene glycol and sodium were simultaneously measured in resting state and during maximum sodium current under stimulation at 10/sec. The influx of sodium increased in these conditions but the influx of ethylene glycol remained constant. In some experiments, the fibre was hyperpolarized to 10 or 20 mV, above the resting potential and the influxes of ethylene glycol and sodium were measured. The sodium influx decreased to 60% at 20 mV above the resting potential whereas the influx of ethylene glycol remained constant.4. These results indicate that in the giant axons of the squid Dosidicus gigas, sodium and non-electrolytes fluxes are not coupled.

  6. Bio-mimetic composite scaffold from mussel shells, squid pen and crab chitosan for bone tissue engineering.

    Science.gov (United States)

    Shavandi, Amin; Bekhit, Alaa El-Din A; Ali, M Azam; Sun, Zhifa

    2015-09-01

    In the present study, chitosan/hydroxyapatite (HA)/β-tircalcium phosphate (β-TCP) composites were produced using squid pen derived chitosan (CHS) and commercial crab derived chitosan (CHC). CHS was prepared from squid pens by alkaline N-deacetylation. HA and β-TCP were extracted from mussel shells using a microwave irradiation method. Two different composites were prepared by incorporating 50% (w/w) HA/(β-TCP) in CHS or CHC followed by lyophilization and cross-linking of composites by tripolyphosphate (TPP). The effect of different freezing temperatures of -20, -80 and -196 °C on the physicochemical characteristics of composites was investigated. A simulated body fluid (SBF) solution was used for preliminary in vitro study for 1, 7, 14 and 28 days and the composites were characterized by XRD, FTIR, TGA, SEM, μ-CT and ICP-MS. Porosity, pore size, water uptake; water retention abilities and in vitro degradations of the prepared composites were evaluated. The CHS composites were found to have higher porosity (62%) compared to the CHC composites (porosity 42%) and better mechanical properties. The results of this study indicated that composites produced at -20 °C had higher mechanical properties and lower degradation rate compared with -80 °C. Chitosan from the squid pen is an excellent biomaterial candidate for bone tissue engineering applications.

  7. Stable isotopes document the trophic structure of a deep-sea cephalopod assemblage including giant octopod and giant squid.

    Science.gov (United States)

    Cherel, Y; Ridoux, V; Spitz, J; Richard, P

    2009-06-23

    Although deep-sea cephalopods are key marine organims, their feeding ecology remains essentially unknown. Here, we report for the first time the trophic structure of an assemblage of these animals (19 species) by measuring the isotopic signature of wings of their lower beaks, which accumulated in stomachs of stranded sperm whales. Overall, the species encompassed a narrow range in delta(13)C values (1.7 per thousand), indicating that they lived in closely related and overlapping habitats. delta(13)C values can be interpreted in terms of distribution with the more (13)C-depleted species (e.g. Stigmatoteuthis arcturi, Vampyroteuthis infernalis) having a more pelagic habitat than the more (13)C-enriched, bathyal species (e.g. Todarodes sagittatus and the giant squid Architeuthis dux). The cephalopods sampled had delta(15)N values ranging 4.6 per thousand, which is consistent with the species spanning approximately 1.5 trophic levels. Neither the giant octopod (Haliphron atlanticus) nor the giant squid reached the highest trophic position. Species delta(15)N was independent of body size, with large squids having both the highest (Taningia danae) and lowest (Lepidoteuthis grimaldii) delta(15)N values. Their trophic position indicates that some species share the top of the food web, together with other megacarnivores such as the sperm whale.

  8. Performance of a 4 Kelvin pulse-tube cooled cryostat with dc SQUID amplifiers for bolometric detector testing

    CERN Document Server

    Barron, Darcy; Keating, Brian; Quillin, Ron; Stebor, Nathan; Wilson, Brandon

    2013-01-01

    The latest generation of cosmic microwave background (CMB) telescopes is searching for the undetected faint signature of gravitational waves from inflation in the polarized signal of the CMB. To achieve the unprecedented levels of sensitivity required, these experiments use arrays of superconducting Transition Edge Sensor (TES) bolometers that are cooled to sub-Kelvin temperatures for photon-noise limited performance. These TES detectors are read out using low- noise SQUID amplifiers. To rapidly test these detectors and similar devices in a laboratory setting, we constructed a cryogenic refrigeration chain consisting of a commercial two-stage pulse-tube cooler, with a base temperature of 3 K, and a closed-cycle 3He/4He/3He sorption cooler, with a base temperature of 220 mK. A commercial dc SQUID system, with sensors cooled to 4 K, was used as a highly-sensitive cryogenic ammeter. Due to the extreme sensitivity of SQUIDs to changing magnetic fields, there are several challenges involving cooling them with puls...

  9. Magnetorelaxometry of few Fe3O4 nanoparticles at 77 K employing a self-compensated SQUID magnetometer

    Science.gov (United States)

    Guillaume, Alexander; Scholtyssek, Jan M.; Lak, Aidin; Kassner, Alexander; Ludwig, Frank; Schilling, Meinhard

    2016-06-01

    Magnetic nanoparticles (MNPs) are of great interest for industrial and medical applications. Therefore, the properties of the particles have to be well controlled. Several magnetic measurement schemes have been developed in order to determine particle parameters such as size distribution and structural properties. In general, systems are designed either for the analysis of large amounts of MNP (≫1000) or for single particle investigation. Up to now, the region in between has been less studied. However, small and well defined amounts of MNPs are of high interest, e.g. for the systematic investigation of particle-particle interactions. In this paper, we present a method using electron beam lithographic preparation of small amounts of MNPs directly on a self-compensating high-temperature superconducting quantum interference device (SQUID) with micrometer dimensions which is insensitive to homogeneous fields and first order gradients but very sensitive to internal magnetic dipole fields. Magnetorelaxometry (MRX) measurements were carried out at 77 K sample temperature in a magnetically shielded room in order to analyze the dynamic behavior of MNP samples and to evaluate the detection limit of our SQUID sensors. Calculations based on the magnetic moment superposition model (MSM) and finite element simulations (FEM) indicate that the MNP samples can be fabricated in a well-defined way by the presented method. Based on MRX measurements of a sample with 200 single-core magnetite MNPs with core diameters of 12 nm, we estimate the detection limit of our SQUID MRX setup as 70 MNPs.

  10. SQUID-based systems for co-registration of ultra-low field nuclear magnetic resonance images and magnetoencephalography

    Science.gov (United States)

    Matlashov, A. N.; Burmistrov, E.; Magnelind, P. E.; Schultz, L.; Urbaitis, A. V.; Volegov, P. L.; Yoder, J.; Espy, M. A.

    2012-11-01

    The ability to perform magnetic resonance imaging (MRI) in ultra-low magnetic fields (ULF) of ∼100 μT, using superconducting quantum interference device (SQUID) detection, has enabled a new class of magnetoencephalography (MEG) instrumentation capable of recording both anatomical (via the ULF MRI) and functional (biomagnetic) information about the brain. The combined ULF MRI/MEG instrument allows both structural and functional information to be co-registered to a single coordinate system and acquired in a single device. In this paper we discuss the considerations and challenges required to develop a combined ULF MRI/MEG device, including pulse sequence development, magnetic field generation, SQUID operation in an environment of pulsed pre-polarization, and optimization of pick-up coil geometries for MRI in different noise environments. We also discuss the design of a “hybrid” ULF MRI/MEG system under development in our laboratory that uses SQUID pick-up coils separately optimized for MEG and ULF MRI.

  11. Characterization of directly coupled YBa{sub 2}Cu{sub 3}O{sub 7-x} SQUID magnetometers

    Energy Technology Data Exchange (ETDEWEB)

    Guillaume, Alexander; Beister, Verena; Scholtyssek, Jan M.; Ludwig, Frank; Schilling, Meinhard [Institut fuer Elektrische Messtechnik und Grundlagen der Elektrotechnik, Technische Universitaet Braunschweig, Hans-Sommer-Str. 66, D-38106 Braunschweig, Germany. (Germany)

    2012-07-01

    Superconducting Quantum Interference Devices (SQUIDs) can be employed as highly sensitive magnetic field sensors in a variety of applications such as magnetoencephalography or magnetic nanoparticle detection. We fabricated SQUIDs from the high-T{sub c} superconductor YBa{sub 2}Cu{sub 3}O{sub 7-x} on symmetric SrTiO{sub 3}-bicrystal substrates by pulsed laser deposition and argon ion etching. The layout consists of two directly coupled magnetometers on one chip which are attached to a rectangular pickup loop. The measurements were carried out in a liquid nitrogen container using a variable temperature insert. The temperature at the magnetically shielded sample holder can be adjusted between 77 K and 100 K. Here, we present measurements of the I-V-curves under the influence of a magnetic field for different sample temperatures. Also, the influence of the temperature and the influence of the bias current on the V-{Phi}-curves were investigated. From these measurements, parameters of the SQUID were calculated and compared to the theoretical estimations. Additionally, noise spectra were recorded for different bias reversal frequencies by using a direct-coupled flux-locked loop electronics from Magnicon GmbH.

  12. SQUID-based systems for co-registration of ultra-low field nuclear magnetic resonance images and magnetoencephalography

    Energy Technology Data Exchange (ETDEWEB)

    Matlashov, A.N., E-mail: matlach@lanl.gov [Los Alamos National Laboratory, P.O. Box 1663, MS-D454, Los Alamos, NM 87545 (United States); Burmistrov, E.; Magnelind, P.E.; Schultz, L.; Urbaitis, A.V.; Volegov, P.L.; Yoder, J.; Espy, M.A. [Los Alamos National Laboratory, P.O. Box 1663, MS-D454, Los Alamos, NM 87545 (United States)

    2012-11-20

    The ability to perform magnetic resonance imaging (MRI) in ultra-low magnetic fields (ULF) of {approx}100 {mu}T, using superconducting quantum interference device (SQUID) detection, has enabled a new class of magnetoencephalography (MEG) instrumentation capable of recording both anatomical (via the ULF MRI) and functional (biomagnetic) information about the brain. The combined ULF MRI/MEG instrument allows both structural and functional information to be co-registered to a single coordinate system and acquired in a single device. In this paper we discuss the considerations and challenges required to develop a combined ULF MRI/MEG device, including pulse sequence development, magnetic field generation, SQUID operation in an environment of pulsed pre-polarization, and optimization of pick-up coil geometries for MRI in different noise environments. We also discuss the design of a 'hybrid' ULF MRI/MEG system under development in our laboratory that uses SQUID pick-up coils separately optimized for MEG and ULF MRI.

  13. Body Size Regression Formulae, Proximate Composition and Energy Density of Eastern Bering Sea Mesopelagic Fish and Squid.

    Science.gov (United States)

    Sinclair, Elizabeth H; Walker, William A; Thomason, James R

    2015-01-01

    The ecological significance of fish and squid of the mesopelagic zone (200 m-1000 m) is evident by their pervasiveness in the diets of a broad spectrum of upper pelagic predators including other fishes and squids, seabirds and marine mammals. As diel vertical migrators, mesopelagic micronekton are recognized as an important trophic link between the deep scattering layer and upper surface waters, yet fundamental aspects of the life history and energetic contribution to the food web for most are undescribed. Here, we present newly derived regression equations for 32 species of mesopelagic fish and squid based on the relationship between body size and the size of hard parts typically used to identify prey species in predator diet studies. We describe the proximate composition and energy density of 31 species collected in the eastern Bering Sea during May 1999 and 2000. Energy values are categorized by body size as a proxy for relative age and can be cross-referenced with the derived regression equations. Data are tabularized to facilitate direct application to predator diet studies and food web models.

  14. Body Size Regression Formulae, Proximate Composition and Energy Density of Eastern Bering Sea Mesopelagic Fish and Squid.

    Directory of Open Access Journals (Sweden)

    Elizabeth H Sinclair

    Full Text Available The ecological significance of fish and squid of the mesopelagic zone (200 m-1000 m is evident by their pervasiveness in the diets of a broad spectrum of upper pelagic predators including other fishes and squids, seabirds and marine mammals. As diel vertical migrators, mesopelagic micronekton are recognized as an important trophic link between the deep scattering layer and upper surface waters, yet fundamental aspects of the life history and energetic contribution to the food web for most are undescribed. Here, we present newly derived regression equations for 32 species of mesopelagic fish and squid based on the relationship between body size and the size of hard parts typically used to identify prey species in predator diet studies. We describe the proximate composition and energy density of 31 species collected in the eastern Bering Sea during May 1999 and 2000. Energy values are categorized by body size as a proxy for relative age and can be cross-referenced with the derived regression equations. Data are tabularized to facilitate direct application to predator diet studies and food web models.

  15. Global observation of 24 November 2006 Pc5 pulsations by single mid-latitude underground [SQUID]2 system

    Directory of Open Access Journals (Sweden)

    M. Parrot

    2011-11-01

    Full Text Available On 24 November 2006, simultaneous observations of Pc5 pulsations, electron precipitation and whistler-mode chorus, as well as solar wind and IMF parameters have been analyzed based on data from IMAGE magnetometers, riometer array and temporal VLF station. This paper focuses on the Pc5 pulsations detected at the same time, in the 1–25 millihertz range, by the [SQUID]2 system (SQUID magnetometer within a Shielding QUalified for Ionosphere Detection installed 518 m underground at 43.92° N, 5.48° E. As expected, the 3-D-frequency spectrum of these mid-latitude [SQUID]2 signals exhibits frequency peaks quasi identical to those observed by polar stations of close geomagnetic longitude. The signal/noise ratio allows the observation of the wave polarization and the beatings of the frequencies. As a result, the possibility of studying, at mid-latitude, magnetic Pc5 pulsations linked with an event in the magnetosphere can improve the description of both behaviour and propagation of these waves.

  16. Magnetite Biomineralization: Fifty years of progress, from beach-combing to the SQUID microscope

    Science.gov (United States)

    Kirschvink, J. L.; Dixson, A. D.; Raub, T.

    2012-12-01

    Magnetite biomineralization was first discovered 50 years ago as a hardening agent in the teeth of the Polyplacophoran molluscs (chitons) by the late Prof. Heinz A. Lowenstam of Caltech, when he noticed unusual erosional effects produced by their grazing in the intertidal zones of Palau (Lowenstam, 1962). Since then, biogenic magnetite has been detected in a broad range of organisms, including magnetotactic bacteria, protists, insects, fish, amphibians, reptiles, birds, and mammals including humans. In many species, the role of ferromagnetic material as a neurophysiological transducer is demonstrated clearly through the effects of pulse-remagnetization on behavior. A brief (1 uS), properly configured magnetic discharge from a rectified LC circuit, tailored to exceed the coercivity of the magnetite, will often abolish a magnetic behavioral response, or in some cases make the organism go the wrong way. This is a unique ferromagnetic effect. The genes controlling magnetite biomineralization are well characterized in several species of bacteria, and the ability of some of these bacterial genes to initiate magnetite precipitation in mammalian cell lines argues for a common descent, probably via a magnetotactic mitochondrial ancestor. Previous studies in fish reported the presence of single-domain magnetite crystals in cells near projections of the trigeminal nerve, co-located in the olfactory epithelium. Although the cells are rare, the recent development of a spinning magnetic field technique allows easy identification and isolation of these cells for individual study (Eder et al., 2012). The cells are surprisingly magnetic, with moments hundreds of times larger than typical magnetotactic bacteria. Subsequent efforts to identify the anatomical seat of magnetoreceptors have focused on the same locations in new organisms, excluding other areas. Using SQUID moment magnetometry and SQUID scanning microscopy, we report here the unexpected presence of biogenic magnetite in

  17. Preparation and copper ions adsorption properties of thiosemicarbazide chitosan from squid pens.

    Science.gov (United States)

    Lin, Yue-Cheng; Wang, Hong-Peng; Gohar, Faryal; Ullah, Muhammad Haseeb; Zhang, Xiang; Xie, Dong-Fang; Fang, Hui; Huang, Jun; Yang, Jun-Xing

    2017-02-01

    Chitosan was prepared by alkaline N-deacetylation of β-chitin from squid pens. Thiosemicarbazide group was introduced to chitosan via formaldehyde-derived linkages, and thiosemicarbazide chitosan (TSFCS) with different degrees of substitution (DS) was synthesized. The DS values of TSFCS calculated by elemental analysis were 0.19, 0.36 and 0.63. The structure of the TSFCS was confirmed by elemental analysis, FTIR, XRD, TGA and SEM. The adsorption capacity of Cu(II) ions by TSFCS showed good correlation with the DS and pH (pH range 2.2-5.8). The maximum Cu(II) ions adsorption capacity of all three TSFCS samples reached 134.0mgg(-1) at pH 3.6, but chitosan showed no adsorption at this pH. The adsorption equilibrium process of Cu(II) ions onto TSFCS was better described by the Langmuir model than the Freundlich isotherm model. Cu(II) ions adsorbed by TSFCS could be released using 0.01M Na2EDTA and the adsorption capacity could retain above 80% after five adsorption-desorption cycles. TSFCS exhibited good potential for heavy metal removal because of its high adsorption capacity at the low pH.

  18. Retinal Development and Ommin Pigment in the Cranchiid Squid Teuthowenia pellucida (Cephalopoda: Oegopsida.

    Directory of Open Access Journals (Sweden)

    Aaron B Evans

    Full Text Available The cranchiid Teuthowenia pellucida, like many deep-sea squid species, possesses large eyes that maximise light sensitivity in a nearly aphotic environment. To assess ontogenetic changes in the visual system, we conducted morphometric and histological analyses of the eyes using specimens from New Zealand collections. While the ratio between eye diameter and mantle length maintained a linear relationship throughout development, histological sections of the retina revealed that the outer photoreceptor layer became proportionally longer as the animal aged, coincident with a habitat shift into deeper, darker ocean strata. Other retinal layers maintained the same absolute thickness as was observed in paralarvae. Granules of the pigment ommin, normally located in the screening layer positioned at the base of the photoreceptors, were also observed at the outer end of the photoreceptor segments throughout the retina in young and mid-sized specimens. Early developmental stages of this species, dwelling in shallow waters, may therefore rely on migratory ommin to help shield photoreceptors from excess light and prevent over-stimulation. The oldest, deeper-dwelling specimens of T. pellucida examined had longer photoreceptors, and little or no migrated ommin was observed; we suggest therefore that short-term adaptive mechanisms for bright light conditions may be used primarily during epipelagic, early life stages in this species.

  19. Investigation of jumbo squid (Dosidicus gigas) skin gelatin peptides for their in vitro antioxidant effects.

    Science.gov (United States)

    Mendis, Eresha; Rajapakse, Niranjan; Byun, Hee-Guk; Kim, Se-Kwon

    2005-09-09

    Peptides derived from tryptic hydrolysate of jumbo squid (Dosidicus gigas) skin gelatin were assessed for their antioxidant properties in different in vitro assay systems. The hydrolysate itself exhibited a strong lipid peroxidation inhibition and it was much higher than that of natural antioxidant, alpha-tocopherol. In addition, it could scavenge highly active free radicals in oxidative systems, in the order of hydroxyl and carbon-centered radicals. Two representative peptides with comparatively higher antioxidant potency were purified and characterized as Phe-Asp-Ser-Gly-Pro-Ala-Gly-Val-Leu (880.18 Da) and Asn-Gly-Pro-Leu-Gln-Ala-Gly-Gln-Pro-Gly-Glu-Arg (1241.59 Da). Furthermore, viability of radical-mediated oxidation-induced human lung fibroblasts was enhanced following the treatment of two peptides. However it did not exhibit substantial ion chelation, and we presumed that the observed radical scavenging potency of these peptides play a vital role for their strong antioxidant activity. Based on our results we suggest that hydrophobic amino acids present in peptide sequences contributed greatly for observed antioxidant activities.

  20. Methods to obtain protein concentrates from jumbo squid (Dosidicus gigas) and evaluation of their functionality.

    Science.gov (United States)

    Galvez-Rongel, A; Ezquerra-Brauer, J M; Ocano-Higuera, V M; Ramirez-Wong, B; Torres-Arreola, W; Rouzaud-Sandez, O; Marquez-Rios, E

    2014-03-01

    Jumbo squid is an important fishery resource in Mexico, and its muscle is lean and white and it has a very low price in the market. It is abundant, but with little or nothing added value, therefore is necessary to search alternatives of processing. Due to muscle characteristics, the aim of this study was to obtain protein concentrates using different methods. They were obtained by means of acidic (acid protein concentrates) and alkaline (alkaline protein concentrates) dissolution. Moreover, a protein concentrate was obtained by direct isoelectric precipitation and by the traditional method (neutral protein concentrates). The yield with better results was alkaline protein concentrates (63.58 ± 1.8%). The gel hardness was significantly different (p < 0.05), especially for the alkaline protein concentrates. The acid protein concentrates, isoelectric precipitation and alkaline protein concentrates were better with regard to the neutral protein concentrates, concerning the emulsifying and foaming properties. The protein concentrates by means of alkaline dissolution gave a better gelling property, but all the processes had the potential to obtain protein with emulsifying and foaming properties.

  1. Salting-in effect on muscle protein extracted from giant squid (Dosidicus gigas).

    Science.gov (United States)

    Zhang, Rui; Zhou, Ru; Pan, Weichun; Lin, Weiwei; Zhang, Xiuzhen; Li, Mengya; Li, Jianrong; Niu, Fuge; Li, Ang

    2017-01-15

    The salting-in effect on muscle protein is well-known in food science but hard to explain using conventional theories. Myofibrillar protein extracted from the giant squid (Dosidicus gigas) was selected as a model muscle protein to study this mechanism in KCl solutions. Changes in the secondary structures of myofibrillar protein molecules caused by concentrated salts, particularly in the paramyosin molecule conformation, have been reported. Zeta-potential determinations showed that these secondary structures have modified protein molecule surfaces. The zeta-potential of the myofibrillar protein molecules fell from -7.24±0.82 to -9.99±1.65mV with increasing salt concentration from 0.1 to 0.5M. The corresponding second virial coefficient increased from -85.43±3.8×10(-7) to -3.45±1.3×10(-7) molmLg(-2). The extended law of corresponding states suggests that reduced attractive interactions increase the protein solubility. Solubility measurements in alternating KCl concentrations showed that the conformational change was reversible.

  2. SQUID-Detected MRI in the Limit of Zero Static Field

    Energy Technology Data Exchange (ETDEWEB)

    Kelso, Nathan Dean [Univ. of California, Berkeley, CA (United States)

    2009-12-14

    This thesis describes an implementation of the so-called"zero-field MRI" (ZFMRI) pulse sequence, which allows for imaging in an arbitrarily low B0 field. The ZFMRI sequence created an effective unidirectional gradient field by using a train of pi pulses to average out the concomitant gradient components during encoding. The signals were acquired using a low-transition temperature dc Superconducting QUantum Interference Device (low-Tc dc SQUID) coupled to a first-order axial gradiometer. The experiments were carried out in a liquid helium dewar which was magnetically shielded with a single-layer mu-metal can around the outside and a superconducting Pb can contained within the helium space. We increased the filling factor of the custom-made, double-walled Pyrex insert by placing the liquid alcohol sample, at a temperature of approximately -50 degrees C, at the center of one loop of the superconducting gradiometer, which was immersed in the helium bath.

  3. Ndel1-derived peptides modulate bidirectional transport of injected beads in the squid giant axon

    Directory of Open Access Journals (Sweden)

    Michal Segal

    2012-01-01

    Bidirectional transport is a key issue in cellular biology. It requires coordination between microtubule-associated molecular motors that work in opposing directions. The major retrograde and anterograde motors involved in bidirectional transport are cytoplasmic dynein and conventional kinesin, respectively. It is clear that failures in molecular motor activity bear severe consequences, especially in the nervous system. Neuronal migration may be impaired during brain development, and impaired molecular motor activity in the adult is one of the hallmarks of neurodegenerative diseases leading to neuronal cell death. The mechanisms that regulate or coordinate kinesin and dynein activity to generate bidirectional transport of the same cargo are of utmost importance. We examined how Ndel1, a cytoplasmic dynein binding protein, may regulate non-vesicular bidirectional transport. Soluble Ndel1 protein, Ndel1-derived peptides or control proteins were mixed with fluorescent beads, injected into the squid giant axon, and the bead movements were recorded using time-lapse microscopy. Automated tracking allowed for extraction and unbiased analysis of a large data set. Beads moved in both directions with a clear bias to the anterograde direction. Velocities were distributed over a broad range and were typically slower than those associated with fast vesicle transport. Ironically, the main effect of Ndel1 and its derived peptides was an enhancement of anterograde motion. We propose that they may function primarily by inhibition of dynein-dependent resistance, which suggests that both dynein and kinesin motors may remain engaged with microtubules during bidirectional transport.

  4. Front-end Multiplexing - applied to SQUID multiplexing : Athena X-IFU and QUBIC experiments

    CERN Document Server

    Prêle, Damien

    2015-01-01

    As we have seen for digital camera market and a sensor resolution increasing to "megapixels", all the scientific and high-tech imagers (whatever the wave length - from radio to X-ray range) tends also to always increases the pixels number. So the constraints on front-end signals transmission increase too. An almost unavoidable solution to simplify integration of large arrays of pixels is front-end multiplexing. Moreover, "simple" and "efficient" techniques allow integration of read-out multiplexers in the focal plane itself. For instance, CCD (Charge Coupled Device) technology has boost number of pixels in digital camera. Indeed, this is exactly a planar technology which integrates both the sensors and a front-end multiplexed readout. In this context, front-end multiplexing techniques will be discussed for a better understanding of their advantages and their limits. Finally, the cases of astronomical instruments in the millimeter and in the X-ray ranges using SQUID (Superconducting QUantum Interference Device...

  5. Self-heterodyne detection of the {\\it in-situ} phase of an atomic-SQUID

    CERN Document Server

    Mathew, Ranchu; Eckel, Stephen; Jendrzejewski, Fred; Campbell, Gretchen K; Edwards, Mark; Tiesinga, Eite

    2015-01-01

    We present theoretical and experimental analysis of an interferometric measurement of the {\\it in-situ} phase drop across and current flow through a rotating barrier in a toroidal Bose-Einstein condensate (BEC). This experiment is the atomic analog of the rf-superconducting quantum interference device (SQUID). The phase drop is extracted from a spiral-shaped density profile created by the spatial interference of the expanding toroidal BEC and a reference BEC after release from all trapping potentials. We characterize the interferometer when it contains a single particle, which is initially in a coherent superposition of a torus and reference state, as well as when it contains a many-body state in the mean-field approximation. The single-particle picture is sufficient to explain the origin of the spirals, to relate the phase-drop across the barrier to the geometry of a spiral, and to bound the expansion times for which the {\\it in-situ} phase can be accurately determined. Mean-field estimates and numerical sim...

  6. Nanohertz Frequency Determination for the Gravity Probe B HF SQUID Signal

    CERN Document Server

    Salomon, M; Kozaczuk, J; Berberian, J E; Santiago, D I; Keiser, G M; Silbergleit, A S; Worden, P

    2011-01-01

    In this paper, we present a method to measure the frequency and the frequency change rate of a digital signal. This method consists of three consecutive algorithms: frequency interpolation, phase differencing, and a third algorithm specifically designed and tested by the authors. The succession of these three algorithms allowed a 5 parts in 10^10 resolution in frequency determination. The algorithm developed by the authors can be applied to a sampled scalar signal such that a model linking the harmonics of its main frequency to the underlying physical phenomenon is available. This method was developed in the framework of the Gravity Probe B (GP-B) mission. It was applied to the High Frequency (HF) component of GP-B's Superconducting QUantum Interference Device (SQUID) signal, whose main frequency fz is close to the spin frequency of the gyroscopes used in the experiment. A 30 nHz resolution in signal frequency and a 0.1 pHz/sec resolution in its decay rate were achieved out of a succession of 1.86 second-long...

  7. Magnetic anisotropy of polycrystalline magnetoferritin investigated by SQUID and electron magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Moro, F., E-mail: fabrizio.moro@nottingham.ac.uk [School of Physics, University of Nottingham, NG7 2RD Nottingham (United Kingdom); Miguel, R. de [Laboratorio de Microscopías Avanzadas (LMA), Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza (Spain); Jenkins, M. [Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza-CSIC, 50009 Zaragoza (Spain); Gómez-Moreno, C. [Laboratorio de Microscopías Avanzadas (LMA), Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza (Spain); Sells, D.; Tuna, F. [EPSRC National UK EPR Facility, Photon Science Institute, University of Manchester, Manchester, M13 9PL (United Kingdom); McInnes, E.J.L. [EPSRC National UK EPR Facility, Photon Science Institute, University of Manchester, Manchester, M13 9PL (United Kingdom); School of Chemistry, University of Manchester, Manchester M13 9PL (United Kingdom); Lostao, A. [Laboratorio de Microscopías Avanzadas (LMA), Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza (Spain); Fundación ARAID (Spain); Luis, F. [Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza-CSIC, 50009 Zaragoza (Spain); Slageren, J. van [Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany)

    2014-06-01

    Magnetoferritin molecules with an average inorganic core diameter of 5.7±1.6 nm and polycrystalline internal structure were investigated by a combination of transmission electron microscopy, magnetic susceptibility, magnetization, and electron magnetic resonance (EMR) experiments. The temperature and frequency dependence of the magnetic susceptibility allowed for the determination of the magnetic anisotropy on an experimental time scale which spans from seconds to nanoseconds. In addition, angle-dependent EMR experiments were carried out for the determination of the nanoparticle symmetry and internal magnetic field. Due to the large surface to volume ratio, the nanoparticles show larger and uniaxial rather than cubic magnetic anisotropies compared to bulk maghemite and magnetite. - Highlights: • Synthesis of polycristalline magnetoferritin with average particle size of 5.7 nm. • Observation of surface effects and estimation of the anisotropy constant and energy barrier by a combined SQUID and EMR study. • Deviation of Gilbert relaxation of the magnetization in magnetoferritin. • Determination of particle symmetry and internal magnetic field by angle-dependent EMR studies.

  8. Integration of a Cryocooler into a SQUID Magnetospinography System for Reduction of Liquid Helium Consumption

    Science.gov (United States)

    Adachi, Yoshiaki; Oyama, Daisuke; Kawai, Jun; Ogata, Hisanao; Uehara, Gen

    We are currently developing a magnetospinography (MSG) system for noninvasive functional imaging of the spinal cord. The MSG system is a device for observing a weak magnetic field accompanied by the neural activity of the spinal cord by using an array of low-temperature superconducting quantum interference device (SQUID) magnetic flux sensors. As in the case of other biomagnetic measurement systems such as the magnetoencephalography (MEG) system, the running cost of the MSG system is mainly dependent on the liquid helium (LHe) consumption of a dewar vessel. We integrated a cryocooler into the MSG system to reduce LHe consumption. A pulse tube cryocooler with a cooling power of 0.5Wat 4 K was placed adjacent to a magnetically shielded room and was directly connected to the thermal radiation shield of the dewar by an electrically isolated transfer tube. Cold helium gas was circulated between the cryocooler and the radiation shield. Consequently, the temperature of the radiation shield decreased below 40 K. Previous studies have shown that the detection of a weak magnetic field is often hindered by severe low-frequency band noise from the cryocooler. However, the band of the MSG signals is much higher than that of the cryocooler noise. Therefore, the noise can be filtered out and has a less detrimental effect on MSG measurement than on other biomagnetic field measurements such as MEG measurement. As a result, LHe consumption was reduced by 46%, with no increase in the noise floor.

  9. Evolutionary relationships among squids of the family Gonatidae (Mollusca: Cephalopoda) inferred from three mitochondrial loci.

    Science.gov (United States)

    Lindgren, A R; Katugin, O N; Amezquita, E; Nishiguchi, M K

    2005-07-01

    The oceanic squid family Gonatidae (Mollusca: Cephalopoda) is widely distributed in subpolar and temperate waters, exhibiting behavioral and physiological specializations associated with reproduction. Females of several species undergo muscular degeneration upon maturation; origins of this complex morphogenic change are unknown, hindering our understanding of ecological and morpho-physiological adaptations within the family. To provide further information regarding the evolutionary relationships within Gonatidae, three mitochondrial loci (12S rRNA, 16S rRNA, and cytochrome c oxidase subunit I) were analyzed for 39 individuals representing fourteen gonatid and six outgroup cephalopod species. In addition to elucidating relationships among gonatids, molecular data provided more information than morphological data for problematic specimens. Although some data sets are incongruent or have low nodal support values, combined molecular analysis confirms the presence of gonatid groups previously established by morphological characteristics (i.e., possessing radular teeth in seven longitudinal rows and muscular mantle tissue). These characteristics are basal to taxa possessing radular teeth in five longitudinal rows and less muscular mantle tissue, indicating that the derived forms are those species exhibiting physiological adaptation such as tissue degeneration upon maturation and egg brooding.

  10. Differential conductivity mapping of solar panels using a high-T{sub C} superconductor SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Kiwa, T., E-mail: kiwa@elec.okayama-u.ac.jp [Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama 700-8530 (Japan); Maeda, S.; Miyake, K.; Kataoka, N. [Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama 700-8530 (Japan); Tsukamoto, A.; Adachi, S.; Tanabe, K. [Superconductivity Research Laboratory, ISTEC, 1-10-13 Shinonome, Koto-ku, Tokyo 135-0062 (Japan); Kandori, A. [Advanced Research Laboratory, Hitachi, Ltd., 1-280 Higashi-Koigakubo, Kokubunji, Tokyo 185-8601 (Japan); Tsukada, K. [Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama 700-8530 (Japan)

    2011-11-15

    To visualise the distribution of the electric property of solar cells, we developed a differential conductivity mapping system using high-T{sub C} (HTS-) superconductor SQUID with a normal conducting pick-up coil. The bias ac voltage with an offset voltage was applied to a solar panel made from amorphous silicon, and the normal component of the generated magnetic field was lock-in-detected. Thus the measured signal was converted to dB/dV properties, which are inverse-proportional to the differential resistivity, as the function of the offset voltage. By scanning the pick-up coil across the panel surface, we obtained the distribution of dB/dV properties across the solar panel was obtained by scanning the pick-up coil across the panel surface. The distribution of dB/dV on the panel differed between when the light source was on and when it was off. This result suggests that the proposed system is a potential tool for diagnosing the electric properties of solar cells.

  11. Computational Study on a Squid-Like Underwater Robot with Two Undulating Side Fins

    Institute of Scientific and Technical Information of China (English)

    Md. Mahbubar Rahman; Yasuyuki Toda; Hiroshi Miki

    2011-01-01

    The undulating fin propulsion system is an instance of the bio-inspired propulsion systems. In the current study, the swimming motion of a squid-like robot with two undulating side fins, mimicking those of a Stingray or a Cuttlefish, was investigated through flow computation around the body. We used the finite analytic method for space discretization and Euler implicit scheme for time discretization along with the PISO algorithm for velocity pressure coupling. A body-fitted moving grid was generated using the Poisson equation at each time step. Based on the computed results, we discussed the features of the flow field and hydrodynamic forces acting on the body and fin. A simple relationship among the fin's principal dimensions was established. Numerical computation was done for various aspect ratios, fin angles and frequencies in order to validate the proposed relationship among principal dimensions. Subsequently, the relationship was examined base on the distribution of pressure difference between upper and lower surfaces and the distribution of the thrust force. In efficiency calculations, the undulating fins showed promising results. Finally, for the fin, the open characteristics from computed data showed satisfactory conformity with the experimental results.

  12. A semi-quantitative approach to assess biofilm formation using wrinkled colony development.

    Science.gov (United States)

    Ray, Valerie A; Morris, Andrew R; Visick, Karen L

    2012-06-07

    Biofilms, or surface-attached communities of cells encapsulated in an extracellular matrix, represent a common lifestyle for many bacteria. Within a biofilm, bacterial cells often exhibit altered physiology, including enhanced resistance to antibiotics and other environmental stresses. Additionally, biofilms can play important roles in host-microbe interactions. Biofilms develop when bacteria transition from individual, planktonic cells to form complex, multi-cellular communities. In the laboratory, biofilms are studied by assessing the development of specific biofilm phenotypes. A common biofilm phenotype involves the formation of wrinkled or rugose bacterial colonies on solid agar media. Wrinkled colony formation provides a particularly simple and useful means to identify and characterize bacterial strains exhibiting altered biofilm phenotypes, and to investigate environmental conditions that impact biofilm formation. Wrinkled colony formation serves as an indicator of biofilm formation in a variety of bacteria, including both Gram-positive bacteria, such as Bacillus subtilis, and Gram-negative bacteria, such as Vibrio cholerae, Vibrio parahaemolyticus, Pseudomonas aeruginosa, and Vibrio fischeri. The marine bacterium V. fischeri has become a model for biofilm formation due to the critical role of biofilms during host colonization: biofilms produced by V. fischeri promote its colonization of the Hawaiian bobtail squid Euprymna scolopes. Importantly, biofilm phenotypes observed in vitro correlate with the ability of V. fischeri cells to effectively colonize host animals: strains impaired for biofilm formation in vitro possess a colonization defect, while strains exhibiting increased biofilm phenotypes are enhanced for colonization. V. fischeri therefore provides a simple model system to assess the mechanisms by which bacteria regulate biofilm formation and how biofilms impact host colonization. In this report, we describe a semi-quantitative method to assess

  13. Volumetric flow imaging reveals the importance of vortex ring formation in squid swimming tail-first and arms-first.

    Science.gov (United States)

    Bartol, Ian K; Krueger, Paul S; Jastrebsky, Rachel A; Williams, Sheila; Thompson, Joseph T

    2016-02-01

    Squids use a pulsed jet and fin movements to swim both arms-first (forward) and tail-first (backward). Given the complexity of the squid multi-propulsor system, 3D velocimetry techniques are required for the comprehensive study of wake dynamics. Defocusing digital particle tracking velocimetry, a volumetric velocimetry technique, and high-speed videography were used to study arms-first and tail-first swimming of brief squid Lolliguncula brevis over a broad range of speeds [0-10 dorsal mantle lengths (DML) s(-1)] in a swim tunnel. Although there was considerable complexity in the wakes of these multi-propulsor swimmers, 3D vortex rings and their derivatives were prominent reoccurring features during both tail-first and arms-first swimming, with the greatest jet and fin flow complexity occurring at intermediate speeds (1.5-3.0 DML s(-1)). The jet generally produced the majority of thrust during rectilinear swimming, increasing in relative importance with speed, and the fins provided no thrust at speeds >4.5 DML s(-1). For both swimming orientations, the fins sometimes acted as stabilizers, producing negative thrust (drag), and consistently provided lift at low/intermediate speeds (swimming orientation, and η for swimming sequences with clear isolated jet vortex rings was significantly greater (η=78.6±7.6%, mean±s.d.) than that for swimming sequences with clear elongated regions of concentrated jet vorticity (η=67.9±19.2%). This study reveals the complexity of 3D vortex wake flows produced by nekton with hydrodynamically distinct propulsors.

  14. Postmortem biochemical behavior of giant squid (Dosidicus gigas) mantle muscle stored in ice and its relation with quality parameters.

    Science.gov (United States)

    Márquez-Ríos, E; Morán-Palacio, E F; Lugo-Sánchez, M E; Ocano-Higuera, V M; Pacheco-Aguilar, R

    2007-09-01

    Several freshness and spoilage indicators were monitored to characterize the postmortem biochemistry of giant squid (Dosidicus gigas) mantle muscle. Squid samples were obtained directly from the sea and kept at 0 degrees C during a 15-d storage period. Data at zero time were obtained from cryogenically frozen samples at time of capture. The adenosine 5'-triphosphate (ATP) degradation followed a different pattern as compared with that from fish species. ATP was almost completely depleted at 24-h postcatch from 6.54 to <1 micromol/g, while at the same time Hx was the predominant catabolite with a concentration of 4 mumol/g, reaching 6.85 micromol/g at day 15. K-value data followed a logarithmic pattern with time instead of a linear one, with no change after day 3, thus reducing its suitability as a freshness index. The coefficient Hx/AMP seems to be an adequate alternative for this purpose due to its constant increment with time. The high NH4Cl content in mantle muscle (461.3 +/- 24.5 mg of NH4(+)/100 g) derived from its physiological importance for the species compromises the use of the distillation step of the TVB-N analysis commonly used as a spoilage index. This fact explains why the initially high value of TVB-N detected in mantle muscle (243.7 mg N/100 g) did not correlate with the initial low TMA-N content (1.5 +/- 0.1 mg/100 g of muscle). The results suggested that under the experimental conditions the shelf life of squid exceeds 15 d.

  15. Locomotion and behavior of Humboldt squid, Dosidicus gigas, in relation to natural hypoxia in the Gulf of California, Mexico.

    Science.gov (United States)

    Gilly, William F; Zeidberg, Louis D; Booth, J Ashley T; Stewart, Julia S; Marshall, Greg; Abernathy, Kyler; Bell, Lauren E

    2012-09-15

    We studied the locomotion and behavior of Dosidicus gigas using pop-up archival transmitting (PAT) tags to record environmental parameters (depth, temperature and light) and an animal-borne video package (AVP) to log these parameters plus acceleration along three axes and record forward-directed video under natural lighting. A basic cycle of locomotor behavior in D. gigas involves an active climb of a few meters followed by a passive (with respect to jetting) downward glide carried out in a fins-first direction. Temporal summation of such climb-and-glide events underlies a rich assortment of vertical movements that can reach vertical velocities of 3 m s(-1). In contrast to such rapid movements, D. gigas spends more than 80% of total time gliding at a vertical velocity of essentially zero (53% at 0±0.05 m s(-1)) or sinking very slowly (28% at -0.05 to -0.15 m s(-1)). The vertical distribution of squid was compared with physical features of the local water column (temperature, oxygen and light). Oxygen concentrations of ≤20 μmol kg(-1), characteristic of the midwater oxygen minimum zone (OMZ), can influence the daytime depth of squid, but this depends on location and season, and squid can 'decouple' from this environmental feature. Light is also an important factor in determining daytime depth, and temperature can limit nighttime depth. Vertical velocities were compared over specific depth ranges characterized by large differences in dissolved oxygen. Velocities were generally reduced under OMZ conditions, with faster jetting being most strongly affected. These data are discussed in terms of increased efficiency of climb-and-glide swimming and the potential for foraging at hypoxic depths.

  16. Metabolic suppression during protracted exposure to hypoxia in the jumbo squid, Dosidicus gigas, living in an oxygen minimum zone.

    Science.gov (United States)

    Seibel, Brad A; Häfker, N Sören; Trübenbach, Katja; Zhang, Jing; Tessier, Shannon N; Pörtner, Hans-Otto; Rosa, Rui; Storey, Kenneth B

    2014-07-15

    The jumbo squid, Dosidicus gigas, can survive extended forays into the oxygen minimum zone (OMZ) of the Eastern Pacific Ocean. Previous studies have demonstrated reduced oxygen consumption and a limited anaerobic contribution to ATP production, suggesting the capacity for substantial metabolic suppression during hypoxic exposure. Here, we provide a more complete description of energy metabolism and explore the expression of proteins indicative of transcriptional and translational arrest that may contribute to metabolic suppression. We demonstrate a suppression of total ATP demand under hypoxic conditions (1% oxygen, PO2 =0.8 kPa) in both juveniles (52%) and adults (35%) of the jumbo squid. Oxygen consumption rates are reduced to 20% under hypoxia relative to air-saturated controls. Concentrations of arginine phosphate (Arg-P) and ATP declined initially, reaching a new steady state (~30% of controls) after the first hour of hypoxic exposure. Octopine began accumulating after the first hour of hypoxic exposure, once Arg-P breakdown resulted in sufficient free arginine for substrate. Octopine reached levels near 30 mmol g(-1) after 3.4 h of hypoxic exposure. Succinate did increase through hypoxia but contributed minimally to total ATP production. Glycogenolysis in mantle muscle presumably serves to maintain muscle functionality and balance energetics during hypoxia. We provide evidence that post-translational modifications on histone proteins and translation factors serve as a primary means of energy conservation and that select components of the stress response are altered in hypoxic squids. Reduced ATP consumption under hypoxia serves to maintain ATP levels, prolong fuel store use and minimize the accumulation of acidic intermediates of anaerobic ATP-generating pathways during prolonged diel forays into the OMZ. Metabolic suppression likely limits active, daytime foraging at depth in the core of the OMZ, but confers an energetic advantage over competitors that must

  17. Imaging of Her2-targeted magnetic nanoparticles for breast cancer detection: comparison of SQUID-detected magnetic relaxometry and MRI.

    Science.gov (United States)

    Adolphi, Natalie L; Butler, Kimberly S; Lovato, Debbie M; Tessier, T E; Trujillo, Jason E; Hathaway, Helen J; Fegan, Danielle L; Monson, Todd C; Stevens, Tyler E; Huber, Dale L; Ramu, Jaivijay; Milne, Michelle L; Altobelli, Stephen A; Bryant, Howard C; Larson, Richard S; Flynn, Edward R

    2012-01-01

    Both magnetic relaxometry and magnetic resonance imaging (MRI) can be used to detect and locate targeted magnetic nanoparticles, noninvasively and without ionizing radiation. Magnetic relaxometry offers advantages in terms of its specificity (only nanoparticles are detected) and the linear dependence of the relaxometry signal on the number of nanoparticles present. In this study, detection of single-core iron oxide nanoparticles by superconducting quantum interference device (SQUID)-detected magnetic relaxometry and standard 4.7 T MRI are compared. The nanoparticles were conjugated to a Her2 monoclonal antibody and targeted to Her2-expressing MCF7/Her2-18 (breast cancer cells); binding of the nanoparticles to the cells was assessed by magnetic relaxometry and iron assay. The same nanoparticle-labeled cells, serially diluted, were used to assess the detection limits and MR relaxivities. The detection limit of magnetic relaxometry was 125 000 nanoparticle-labeled cells at 3 cm from the SQUID sensors. T(2)-weighted MRI yielded a detection limit of 15 600 cells in a 150 µl volume, with r(1) = 1.1 mm(-1) s(-1) and r(2) = 166 mm(-1) s(-1). Her2-targeted nanoparticles were directly injected into xenograft MCF7/Her2-18 tumors in nude mice, and magnetic relaxometry imaging and 4.7 T MRI were performed, enabling direct comparison of the two techniques. Co-registration of relaxometry images and MRI of mice resulted in good agreement. A method for obtaining accurate quantification of microgram quantities of iron in the tumors and liver by relaxometry was also demonstrated. These results demonstrate the potential of SQUID-detected magnetic relaxometry imaging for the specific detection of breast cancer and the monitoring of magnetic nanoparticle-based therapies.

  18. Integrative omics analysis reveals differentially distributed proteins in dimorphic euspermatozoa of the squid, Loligo bleekeri.

    Science.gov (United States)

    Yoshida, Masa-aki; Yamada, Lixy; Ochi, Hiroe; Iwata, Yoko; Tamura-Nakano, Miwa; Sawada, Hitoshi; Sauer, Warwick H H; Ogura, Atsushi; Hirohashi, Noritaka

    2014-08-01

    In the coastal squid Loligo bleekeri, each male produces one of two types of fertilization-competent spermatozoa (eusperm) that exhibit morphological and behavioral differences. Large "consort" males produce short-tailed spermatozoa that display free-swimming behavior when ejaculated into seawater. Small "sneaker" males, on the other hand, produce long-tailed spermatozoa that exhibit a self-swarming trait after ejaculation. To understand the molecular basis for adaptive traits employed by alternative male mating tactics, we performed the transcriptome deep sequencing (RNA-seq) and proteome analyses to search for differences in testicular mRNAs and sperm proteins, respectively. From mature male testes we identified a total of 236,455 contigs (FPKM ≧1) where 3789 and 2789 were preferentially (≧10-fold) expressed in consort and sneaker testes, respectively. A proteomic analysis detected 4302 proteins in the mature sperm as post-translational products. A strongly biased (≧10-fold) distribution occurred in 55 consort proteins and 61 sneaker proteins. There was no clear mRNA-protein correlation, making a ballpark estimate impossible for not only overall protein abundance but also the degree of biased sperm type expressed in the spermatozoa. A family encoding dynein heavy chain gene, however, was found to be biased towards sneakers, whereas many enzymes involving energy metabolism were heavily biased towards consort spermatozoa. The difference in flagellar length matched exactly the different amount of tubulins. From these results we hypothesize that discrete differential traits in dimorphic eusperm arose from a series of innovative alterations in the intracellular components of spermatozoa.

  19. Enhanced Synaptic Transmission at the Squid Giant Synapse by Artificial Seawater Based on Physically Modified Saline

    Directory of Open Access Journals (Sweden)

    Soonwook eChoi

    2014-02-01

    Full Text Available Superfusion of the squid giant synapse with artificial seawater (ASW based on isotonic saline containing oxygen nanobubbles (RNS60 ASW generates an enhancement of synaptic transmission. This was determined by examining the postsynaptic response to single and repetitive presynaptic spike activation, spontaneous transmitter release, and presynaptic voltage clamp studies. In the presence of RNS60 ASW single presynaptic stimulation elicited larger postsynaptic potentials (PSP and more robust recovery from high frequency stimulation than in control ASW. Analysis of postsynaptic noise revealed an increase in spontaneous transmitter release with modified noise kinetics in RNS60 ASW. Presynaptic voltage clamp demonstrated an increased EPSP, without an increase in presynaptic ICa⁺⁺ amplitude during RNS60 ASW superfusion. Synaptic release enhancement reached stable maxima within 5 to 10 minutes of RNS60 ASW superfusion and was maintained for the entire recording time, up to one hour. Electronmicroscopic morphometry indicated a decrease in synaptic vesicle density and the number at active zones with an increase in the number of clathrin-coated vesicles and large endosome-like vesicles near junctional sites. Block of mitochondrial ATP synthesis by presynaptic injection of oligomycin reduced spontaneous release and prevented the synaptic noise increase seen in RNS60 ASW. After ATP block the number of vesicles at the active zone and clathrin-coated vesicles was reduced, with an increase in large vesicles. The possibility that RNS60 ASW acts by increasing mitochondrial ATP synthesis was tested by direct determination of ATP levels in both presynaptic and postsynaptic structures. This was implemented using luciferin/luciferase photon emission, which demonstrated a marked increase in ATP synthesis following RNS60 administration. It is concluded that RNS60 positively modulates synaptic transmission by up-regulating ATP synthesis, thus leading to synaptic

  20. Tunable microstrip SQUID amplifiers for the Gen 2 Axion Dark Matter eXperiment (ADMX)

    Science.gov (United States)

    O'Kelley, Sean; Hilton, Gene; Clarke, John; ADMX Collaboration

    2016-03-01

    We present a series of tunable microstrip SQUID (Superconducting Quantum Interference Device) amplifiers (MSAs) for installation in ADMX. The axion dark matter candidate is detected via Primakoff conversion to a microwave photon in a high-Q (~100,000) tunable microwave cavity cooled with a dilution refrigerator in a 7-tesla magnetic field. The microwave photon frequency ν is a function of the unknown axion mass, so both the cavity and amplifier must be scanned over a wide frequency range. An MSA is a linear, phase-preserving amplifier consisting of a square washer loop, fabricated from a thin Nb film, incorporating two Josephson tunnel junctions with resistive shunts to prevent hysteresis. The input is coupled via a microstrip made from a square Nb coil deposited over the washer with an intervening insulating layer. Tunability is achieved by terminating the microstrip with GaAs varactors that operate below 100 mK. By varying the varactor capacitance with a bias voltage, the resonant frequency is varied by up to a factor of 2. We demonstrate several devices operating below 100 mK, matched to the discrete operating bands of ADMX at frequencies ranging from 560 MHz to 1 GHz. The MSAs exhibit gains exceeding 20 dB and the associated noise temperatures, measured with a hot/cold load, approach the standard quantum limit (hν/kB) . Supported by DOE Grants DE - FG02 - 97ER41029, DE - FG02 - 96ER40956, DE - AC52 - 07NA27344, DE - AC03 - 76SF00098, and the Livermore LDRD program.

  1. Active polysomes are present in the large presynaptic endings of the synaptosomal fraction from squid brain.

    Science.gov (United States)

    Crispino, M; Kaplan, B B; Martin, R; Alvarez, J; Chun, J T; Benech, J C; Giuditta, A

    1997-10-15

    Previous data have suggested that the large nerve terminals present in the synaptosomal fraction from squid optic lobe are capable of protein synthesis (Crispino et al., 1993a,b). We have further examined this issue by comparing the translation products of synaptosomal and microsomal polysomes. Both preparations programmed an active process of translation, which was completely abolished by their previous treatment with EDTA. After immunoabsorption of the newly synthesized neurofilament (NF) proteins, the labeling ratio of the 60 and 70 kDa NF proteins was found to differ, in agreement with comparable differences obtained with intact synaptosomes. These observations indicate that the set of mRNAs translated by synaptosomes differs from that translated by nerve cell bodies. Hence, because NF proteins are neuron-specific, they support the view that the active synaptosomal polysomes are mostly localized in the large nerve terminals that represent the most abundant neuronal component of the fraction. This hypothesis was confirmed (1) by electron spectroscopic data demonstrating the presence of ribosomes and polysomes within the large nerve endings of the synaptosomal fraction, as well as in the carrot-like nerve endings of the retinal photoreceptors that constitute the only large terminals in the optic lobe, and (2) by light and high resolution autoradiography of synaptosomal samples incubated with [3H]leucine, showing that most labeled proteins are associated with the large nerve endings. This response was abolished by cycloheximide. Taken together, the data provide the first unequivocal demonstration that presynaptic nerve terminals are capable of protein synthesis.

  2. Methyl Quantum Tunneling and NITROGEN-14 Nqr Studies Using a DC SQUID Magnetic Resonance Spectrometer.

    Science.gov (United States)

    Black, Bruce Elmer

    Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) techniques have been very successful in obtaining molecular conformation and dynamics information. Unfortunately, standard NMR and NQR spectrometers are unable to adequately detect resonances below a few megahertz due to the frequency dependent sensitivity of their Faraday coil detectors. For this reason a new spectrometer with a dc SQUID (Superconducting Quantum Interference Device) detector, which has no such frequency dependence, has been developed. Previously, this spectrometer was used to observe ^ {11}B and ^{27} Al NQR resonances. I have increased the scope of this study to include ^{23}Na, ^{51}V, and ^ {55}Mn NQR transitions. Also, I present a technique to observe ^{14}N NQR resonances through cross relaxation of the nitrogen polarization to adjacent proton spins. When the proton Zeeman splitting matches one nitrogen quadrupolar transition the remaining two ^ {14}N transitions can be detected by sweeping a saturating rf field through resonance. Additionally, simultaneous excitation of two nitrogen resonances provides signal enhancement which helps to connect transitions from the same site. In this way, we have observed nitrogen -14 resonances in several amino acids and polypeptides. This spectrometer has also been useful in the direct detection of methyl quantum tunneling splittings at 4.2 K. Tunneling frequencies of a homologous series of carboxylic acids were measured and for solids with equivalent crystal structures, an exponential correlation between the tunneling frequency and the enthalpy of fusion is observed. This correlation provides information about the contribution of intermolecular interactions to the energy barrier for methyl rotation.

  3. 高温超导磁强计在瞬变电磁法中的应用研究%The applications of HTc SQUID magnetometer to TEM

    Institute of Scientific and Technical Information of China (English)

    陈晓东; 赵毅; 张杰; 吕国印; 马平; 戴远东

    2012-01-01

    通过对高温超导磁强计的不断完善,研制出了适合在瞬变电磁法中使用的高温超导磁强计,实现了在瞬变电磁法中直接测量磁场的目的.同时开展了瞬变电磁法感应磁场的数据处理与解释技术研究,开发了瞬变电磁法感应磁场的电性成像软件,可以对使用高温超导磁强计作传感器测得的瞬变电磁感应磁场数据进行处理与电性成像.野外实验表明:高温超导磁强计工作稳定,在瞬变电磁法中使用高温超导磁强计比使用感应线圈做传感器提高了勘探深度.%HTc SQUID magnetometer is characterized by low noise, high sensitivity, wide dynamic and frequency ranges and can be used as a B field sensor. Theoretically, the HTc RF SQUID magnetometer has superiority over conventional inductive coil in TEM application. Since 1989,Bejing University and IGGE have been developing HTc SQUID magnetometers for geophysical exploration. We have manufactured the HTc SQUID magnetometer adapted to several commercial TEM system, and realized measuring magnetic field directly in TEM. IGGE also have studied the data processing and interpretation technology and have developed resistivity imaging software for the data acquired with HTc SQUID magnetometer. The results of the field tests show that larger detection depth could be expected in TEM survey by using HTS RF SQUID magnetometer.

  4. Detection of spatial hot spots and variation for the neon flying squid Ommastrephes bartramii resources in the northwest Pacific Ocean

    Science.gov (United States)

    Feng, Yongjiu; Chen, Xinjun; Liu, Yan

    2016-08-01

    With the increasing effects of global climate change and fishing activities, the spatial distribution of the neon flying squid (Ommastrephes bartramii) is changing in the traditional fishing ground of 150°-160°E and 38°-45°N in the northwest Pacific Ocean. This research aims to identify the spatial hot and cold spots (i.e. spatial clusters) of O. bartramii to reveal its spatial structure using commercial fishery data from 2007 to 2010 collected by Chinese mainland squid-jigging fleets. A relatively strongly-clustered distribution for O. bartramii was observed using an exploratory spatial data analysis (ESDA) method. The results show two hot spots and one cold spot in 2007 while only one hot and one cold spots were identified each year from 2008 to 2010. The hot and cold spots in 2007 occupied 8.2% and 5.6% of the study area, respectively; these percentages for hot and cold spot areas were 5.8% and 3.1% in 2008, 10.2% and 2.9% in 2009, and 16.4% and 11.9% in 2010, respectively. Nearly half (>45%) of the squid from 2007 to 2009 reported by Chinese fleets were caught in hot spot areas while this percentage reached its peak at 68.8% in 2010, indicating that the hot spot areas are central fishing grounds. A further change analysis shows the area centered at 156°E/43.5°N was persistent as a hot spot over the whole period from 2007 to 2010. Furthermore, the hot spots were mainly identified in areas with sea surface temperature (SST) in the range of 15-20°C around warm Kuroshio Currents as well as with the chlorophyll-a (chl-a) concentration above 0.3 mg/m3. The outcome of this research improves our understanding of spatiotemporal hotspots and its variation for O. bartramii and is useful for sustainable exploitation, assessment, and management of this squid.

  5. An NLMS algorithm with optimized preparatory step-size parameters for SQUID-based MCG data processing

    Institute of Scientific and Technical Information of China (English)

    Li Zhuo; Chen Geng-Hua; Zhang Li-Hua; Yang Qian-Sheng; Feng Ji

    2006-01-01

    We present a new least-mean-square algorithm of adaptive filtering to improve the signal to noise ratio for magneto-cardiography data collected with high-temperature SQUID-based magnetometers. By frequently adjusting the adaptive parameter a to systematic optimum values in the course of the programmed procedure, the convergence is accelerated with a highest speed and the minimum steady-state error is obtained simultaneously. This algorithm may be applied to eliminate other non-steady relevant noises as well.

  6. Baseline of organotin pollution in fishes, clams, shrimps, squids and crabs collected from the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Jadhav, S.; Bhosale, D.; Bhosle, N.B.

    is available. The present study was planned to assess organotin contamination levels in edible marine organisms collected from the fish markets of Goa, Karwar and Mumbai, the west coast of India. The sampling locations: Goa (15.5ºN, 73.9ºE), Karwar (14.8º... of Karwar is around 36,000 tonnes. Mumbai coast is about 140 km long. Mumbai is among busiest harbours on the west coast of India is known for industrial pollution. The fishes, clams, crabs and squids and shrimps were collected from local fish markets...

  7. On the occurrence of egg masses of the diamond-shaped squid Thysanoteuthis rhombus Troschel, 1857 in the subtropical eastern Atlantic (Canary Islands. A potential commercial species?

    Directory of Open Access Journals (Sweden)

    Alejandro Escanez

    2012-09-01

    Full Text Available Data on opportunistic sightings of diamond-shaped squid Thysanoteuthis rhombus egg masses in the Canary Islands (Atlantic Ocean are presented. A total of 16 egg masses of this species were recorded and photographed from 2000 to 2010 around the western islands of the archipelago (El Hierro, Tenerife and La Gomera. These data reveal the existence of an important spawning area for diamond-shaped squid around the Canary Islands, in subtropical east Atlantic waters. We provide preliminary data for the potential development of an artisanal fishery focused on this species, and a discussion on its potential impacts on the marine ecosystem.

  8. Purification and in vitro antioxidative effects of giant squid muscle peptides on free radical-mediated oxidative systems.

    Science.gov (United States)

    Rajapakse, Niranjan; Mendis, Eresha; Byun, Hee-Guk; Kim, Se-Kwon

    2005-09-01

    Low molecular weight peptides obtained from ultrafiltration (UF) of giant squid (Dosidicus gigas) muscle protein were studied for their antioxidative effects in different in vitro oxidative systems. The most potent two peptides, Asn-Ala-Asp-Phe-Gly-Leu-Asn-Gly-Leu-Glu-Gly-Leu-Ala (1307 Da) and Asn-Gly-Leu-Glu-Gly-Leu-Lys (747 Da), exhibited their antioxidant potential to act as chain-breaking antioxidants by inhibiting radical-mediated peroxidation of linoleic acid, and their activities were closer to highly active synthetic antioxidant, butylated hydroxytoluene. Addition of these peptides could enhance the viability of cytotoxic embryonic lung fibroblasts significantly (P<.05) at a low concentration of 50 microg/ml, and it was presumed due to the suppression of radical-induced oxidation of membrane lipids. Electron spin trapping studies revealed that the peptides were potent scavengers of free radicals in the order of carbon-centered (IC(50) 396.04 and 304.67 microM), hydroxyl (IC(50) 497.32 and 428.54 microM) and superoxide radicals (IC(50) 669.34 and 573.83 microM). Even though the exact molecular mechanism for scavenging of free radicals was unclear, unusually high hydrophobic amino acid composition (more than 75%) of giant squid muscle peptides was presumed to be involved in the observed activities.

  9. Isolation and properties of AMP deaminase from jumbo squid (Dosidicus gigas) mantle muscle from the Gulf of California, Mexico.

    Science.gov (United States)

    Marquez-Rios, E; Pacheco-Aguilar, R; Castillo-Yañez, F J; Figueroa-Soto, C G; Ezquerra-Brauer, J M; Gollas-Galvan, T

    2008-09-01

    Adenosine monophosphate (AMP) deaminase was purified from jumbo squid mantle muscle by chromatography in cellulose phosphate, Q-Fast and 5'-AMP sepharose. Specific activity of 2.5U/mg protein, 4.5% recovery and 133.68 purification fold were obtained at the end of the experiment. SDS-PAGE showed a single band with 87kDa molecular mass, native PAGE proved a band of 178kDa, whereas gel filtration detected a 180kDa protein, suggesting the homodimeric nature of this enzyme, in which subunits are not linked by covalent forces. Isoelectric focusing of this enzyme showed a pI of 5.76, which agrees with pI values of AMP deaminase from other invertebrate organisms. AMP deaminase presented a kinetic sigmoidal plot with Vmax of 1.16μM/min/mg, Km of 13mM, Kcat of 3.48μM.s(-1) and a Kcat/Km of 267 (mol/L)(-1).s(-1). The apparent relative low catalytic activity of jumbo squid muscle AMP deaminase in the absence of positive effectors is similar to that reported for homologous enzymes in other invertebrate organisms.

  10. The jumbo squid, Dosidicus gigas (Ommastrephidae), living in oxygen minimum zones I: Oxygen consumption rates and critical oxygen partial pressures

    Science.gov (United States)

    Trueblood, Lloyd A.; Seibel, Brad A.

    2013-10-01

    Dosidicus gigas is a large, metabolically active, epipelagic squid known to undertake diel vertical migrations across a large temperature and oxygen gradient in the Eastern Pacific. Hypoxia is known to cause metabolic suppression in D. gigas. However, the precise oxygen level at which metabolic suppression sets in is unknown. Here we describe a novel ship-board swim tunnel respirometer that was used to measure metabolic rates and critical oxygen partial pressures (Pcrit) for adult squids (2-7kg). Metabolic rate measurements were validated by comparison to the activity of the Krebs cycle enzyme, citrate synthase, in mantle muscle tissue (2-17kg). We recorded a mean routine metabolic rate of 5.91μmolg-1h-1 at 10°C and 12.62μmolg-1h-1 at 20°C. A temperature coefficient, Q10, of 2.1 was calculated. D. gigas had Pcrits of 1.6 and 3.8kPa at 10 and 20°C, respectively. Oxygen consumption rate (MO2) varied with body mass (M) according to MO2=11.57M-0.12±0.03 at 10°C. Citrate synthase activity varied with body mass according to Y=9.32M-0.19±0.02.

  11. Differential impacts of ocean acidification and warming on winter and summer progeny of a coastal squid (Loligo vulgaris).

    Science.gov (United States)

    Rosa, Rui; Trübenbach, Katja; Pimentel, Marta S; Boavida-Portugal, Joana; Faleiro, Filipa; Baptista, Miguel; Dionísio, Gisela; Calado, Ricardo; Pörtner, Hans O; Repolho, Tiago

    2014-02-15

    Little is known about the capacity of early life stages to undergo hypercapnic and thermal acclimation under the future scenarios of ocean acidification and warming. Here, we investigated a comprehensive set of biological responses to these climate change-related variables (2°C above winter and summer average spawning temperatures and ΔpH=0.5 units) during the early ontogeny of the squid Loligo vulgaris. Embryo survival rates ranged from 92% to 96% under present-day temperature (13-17°C) and pH (8.0) scenarios. Yet, ocean acidification (pH 7.5) and summer warming (19°C) led to a significant drop in the survival rates of summer embryos (47%, Pocean acidification and summer warming scenarios. The occurrence of prolonged embryogenesis along with lowered thermal tolerance limits under such conditions is expected to negatively affect the survival success of squid early life stages during the summer spawning period, but not winter spawning.

  12. Relationship Between Beak Morphological Variables and Body Size and Mantle Length of Male and Female Argentine Shortfin Squid (Illex argentinus)

    Institute of Scientific and Technical Information of China (English)

    CHEN Xinjun; LU Huajie; LIU Bilin; FANG Zhou

    2012-01-01

    Beak of cephalopod is an important hard tissue.Understanding the morphology of beak can yield critical information on the role of cephalopods in the ecosystem.The south patagonic stock of the Argentine shortfin squid,Illex argentinus,is not only one of the most important fishing targets,but also one of the most important species in the marine eco-system of the southwest Atlantic.A total of 430 samples of I.argentinus,including 229 females 103-346mm in mantle length (ML) and 201males 140-298mm in ML,were collected from the area off the Exclusive Economic Zone of Argentinean waters by Chinese squid jigging vessels during February to May 2007.The morphology of their beaks was evaluated.The relationships between beak morphological variables and ML differed significantly among males and females.They could be best described by logarithmic functions for females and linear functions for males except for upper wing length (UWL) and lower rostrum length (LRL),which followed exponential functions in their relationships with ML.The results showed the sexual dimorphism in the relationship between ML and beak morphology for the south patagonic stock of I.argentinus.However,no significant difference was found between males and females in the relationships of beak morphological variables (except for UWL) versus body weight (BW),suggesting that the relationship between beak morphological variables and BW can be used for estimating the biomass consumed by their predators.

  13. Highly Sensitive Measurements of the Dark Current of Superconducting Cavities for TESLA Using a SQUID Based Cryogenic Current Comparator

    CERN Document Server

    Vodel, W; Nietzsche, S

    2004-01-01

    This contribution presents a Cryogenic Current Comparator (CCC) as an excellent tool for detecting dark currents generated, e.g. by superconducting cavities for the upcoming TESLA project (X-FEL) at DESY. To achieve the maximum possible energy the gradient of the superconducting RF cavities should be pushed close to the physical limit of 50 MV/m. The undesired field emission of electrons (so-called dark current) of the superconducting RF cavities at strong fields may limit the maximum gradient. The absolute measurement of the dark current in correlation with the gradient will give a proper value to compare and classify the cavities. The main component of the CCC is a highly sensitive LTS-DC SQUID system which is able to measure extremely low magnetic fields, e.g. caused by the dark current. For this reason the input coil of the SQUID is connected across a special designed toroidal niobium pick-up coil for the passing electron beam. A noise limited current resolution of nearly 2 pA/√(Hz) with a measu...

  14. Observations on the spawning behavior, egg masses and paralarval development of the ommastrephid squid Todarodes pacificus in a laboratory mesocosm.

    Science.gov (United States)

    Puneeta, Pandey; Vijai, Dharmamony; Yoo, Hae-Kyun; Matsui, Hajime; Sakurai, Yasunori

    2015-12-01

    The spawning behavior of ommastrephid squids has never been observed under natural conditions. Previous laboratory observations of Japanese flying squid (Todarodes pacificus) suggest that pre-spawning females might rest on the continental shelf or slope before they ascend above the pycnocline to spawn, and that the egg masses might settle in the pycnocline. Here, two mesocosm experiments were conducted in a 300 m(3) tank that was 6 m deep to investigate this hypothesis. In the first experiment, a thermocline (2.5-3.5 m) was established in the tank by creating a thermally stratified (17-22°C) water column. In the second experiment, the temperature was uniform (22°C) at all depths. Prior to spawning, females did not rest on the tank floor. In the stratified water column, egg masses remained suspended in the thermocline, but in an unstratified water column, they settled on the tank bottom, collapsed and were infested by microbes, resulting in abnormal or nonviable embryos. Eleven females spawned a total of 18 egg masses (17-80 cm in diameter), indicating that females can spawn more than once when under stress. Paralarvae hatched at stage 30/31 and survived for up to 10 days, allowing us to observe the most advanced stage of paralarvae in captivity. Paralarvae survived after consumption of the inner yolk, suggesting they might have fed in the tank.

  15. Feasibility study of contaminant detection for food with ULF-NMR/MRI system using HTS-SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukade, Yoshimi, E-mail: hatukade@ens.tut.ac.jp; Tsunaki, Shingo; Yamamoto, Masaaki; Abe, Takayuki; Hatta, Junichi; Tanaka, Saburo

    2013-11-15

    Highlights: •Feasibility of application of ultra-low field (ULF) NMR/MRI was studied. •ULF-NMR/MRI system utilized HTS-rf-SQUID and permanent magnet of 1.1 T. •Magnetic contaminants in water were successfully detected by NMR measurements. •Non-magnetic contaminants in water were distinguished by 1D-MRI measurements. -- Abstract: We have developed an ultra-low frequency (ULF) nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) system utilizing an HTS-SQUID for an application of contaminant detection in food and drink. In the system, a permanent magnet of 1.1 T was used to pre-polarize protons in a water sample. We measured NMR signals from water samples with or without various contaminants, such as stainless steel (SUS304), aluminum, and glass balls using the system. In the case that the contaminant was the SUS304 ball, the NMR signal intensity was reduced compared to that from the sample without the contaminant due to the remnant field of the contaminant. One-dimensional (1D) MRIs of the samples were also acquired to detect non-magnetic contaminants. In the 1D MRIs, changes of the MRI spectra were detected, corresponding to positions of the contaminants. These results show that the feasibility of the system to detect various contaminants in foods.

  16. Collagen Extracted from Persian Gulf Squid Exhibits Anti-Cytotoxic Properties on Apple Pectic Treated Cells: Assessment in an In Vitro Bioassay Model

    Directory of Open Access Journals (Sweden)

    Ladan DELPHI

    2016-10-01

    Full Text Available Background: Collagen-based three-dimensional (3D in vitro systems have been introduced to study the physiological states of cells. As a biomolecule, collagen is usually extracted from terrestrial animals whilst aquatic animals like squid contain large amounts of collagen.Methods: In order to make effective use of marine organisms, we selected Persian Gulf squid in 2015 to extract the required collagen. Then, a 3D culture system based on the extracted collagen was applied to investigate cellular mechanisms in a native microenvironment. The formed collagen gel was used to investigate the growth of MDA-MB-231 breast cancer cells as well as responses to pectic acid.Results: The results revealed that the extracted collagen contained α, ß and γ components with high water holding capacity. This collagen formed a gel-like structure, which could promote the proliferation of MDA-MB-231 breast cancer cells. The MDA-MB-231 cells’ viability in presence of pectic acid, demonstrating the cells’ behavior in a 3D culture system. Conclusion: It seems that the collagen extracted from squid skin has type I collagen properties. It might be used as a substrate in 3D cell culture systems. Keywords: Cell culture, Collagen, Pectic acid, Squid, 3D culture system 

  17. Isolation and Identification of Active Compound Cause Light Emmitting of Bacterial Photobacterium phosphoreum Isolated from the Indonesia Jepara Marine Squid

    Directory of Open Access Journals (Sweden)

    Idam Arif

    2005-04-01

    Full Text Available This research carried out to study the bioluminescence process of bacterial Photobacterium phosphoreum isolated from Indonesia marine squid. The method used in the present study involved isolation, purification, electrophoresis, and the absorbance and light intensity measurement. This result show that the luciferace enzyme of bacterial Photobacterium phosphoreum or called LBPP catalyzes the emission of visible light from the reaction of reduced flavin mononucleotide (FMNH2, molecular oxygen (O2, and an aldehyde (RCOH. The electrophoresis data show that LBPP comprised of two different subunits α and βwith 41kD and 38 kD molecular weights. The absorb pattern showed that the bioluminescence process centered around 516 nm and are consistent with the fluorescence data. This result concluded that the excitation state formed after LBPP bind subtracts and the ground state formed after LBPP releases product and visible light.

  18. Metabolic physiology of the Humboldt squid, Dosidicus gigas: Implications for vertical migration in a pronounced oxygen minimum zone

    Science.gov (United States)

    Rosa, Rui; Seibel, Brad A.

    2010-07-01

    The Humboldt (or jumbo) squid, Dosidicus gigas, is an active predator endemic to the Eastern Pacific that undergoes diel vertical migrations into a pronounced oxygen minimum layer (OML). Here, we investigate the physiological mechanisms that facilitate these migrations and assess the associated costs and benefits. Exposure to hypoxic conditions equivalent to those found in the OML (∼10 μM O 2 at 10 °C) led to a significant reduction in the squid’s routine metabolic rate (RMR), from 8.9 to 1.6 μmol O 2 g -1 h -1 ( p gigas may repay any oxygen debt accumulated during the daytime. The dive to deeper water may minimize exposure to stressful surface temperatures when most prey have migrated to depth during the daytime. The physiological and ecological strategies demonstrated here may have facilitated the recent range expansion of this species into northern waters where expanding hypoxic zones prohibit competing top predators.

  19. Physical-chemical studies of proteins of squid nerve axoplasm, with special reference to the axon fibrous protein.

    Science.gov (United States)

    DAVISON, P F; TAYLOR, E W

    1960-03-01

    The proteins in the axoplasm of the squid, Dosidicus gigas, have been resolved electrophoretically into a major fraction including the fibrous protein, and possibly its structural subunits, and a minor fraction including at least two proteins with low sedimentation coefficients. A partially reversible change in the structure of the fibrous protein occurs under the action of 0.4 M salt or high pH. These experiments have been interpreted to indicate that in the intact fiber one, or a few, protofibrils are arranged helically or longitudinally along the fiber axis, and linked by electrostatic bonds. On the dissociation of these bonds the separated protofibrils assume a less extended form and sediment more rapidly than the intact fibers. Some material with a lower sedimentation rate is also released on the dissociation. This fraction may comprise smaller chain fragments. The volume fraction and the approximate refractive index of the fibers have been calculated.

  20. Use of a SQUID array to detect T-cells with magnetic nanoparticles in determining transplant rejection

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, Edward R. [Senior Scientific, 11109 Country Club NE, Albuquerque, NM 87111 (United States)]. E-mail: seniorsci@nmia.com; Bryant, H.C. [Senior Scientific, 11109 Country Club NE, Albuquerque, NM 87111 (United States); Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 (United States); Bergemann, Christian [Chemicell GmbH, Berlin (Germany); Larson, Richard S. [Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM 87131 (United States); Lovato, Debbie [Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM 87131 (United States); Sergatskov, Dmitri A. [Senior Scientific, 11109 Country Club NE, Albuquerque, NM 87111 (United States)

    2007-04-15

    Acute rejection in organ transplant is signaled by the proliferation of T-cells that target and kill the donor cells requiring painful biopsies to detect rejection onset. An alternative non-invasive technique is proposed using a multi-channel superconducting quantum interference device (SQUID) magnetometer to detect T-cell lymphocytes in the transplanted organ labeled with magnetic nanoparticles conjugated to antibodies specifically attached to lymphocytic ligand receptors. After a magnetic field pulse, the T-cells produce a decaying magnetic signal with a characteristic time of the order of a second. The extreme sensitivity of this technique, 10{sup 5} cells, can provide early warning of impending transplant rejection and monitor immune-suppressive chemotherapy.

  1. Note: Improved sensitivity of magnetic measurements under high pressure in miniature ceramic anvil cell for a commercial SQUID magnetometer.

    Science.gov (United States)

    Tateiwa, Naoyuki; Haga, Yoshinori; Matsuda, Tatsuma D; Fisk, Zachary; Ikeda, Shugo; Kobayashi, Hisao

    2013-04-01

    Two modifications have been made to a miniature ceramic anvil high pressure cell (mCAC) designed for magnetic measurements at pressures up to 12.6 GPa in a commercial superconducting quantum interference (SQUID) magnetometer [N. Tateiwa et al., Rev. Sci. Instrum. 82, 053906 (2011); ibid. 83, 053906 (2012)]. Replacing the Cu-Be piston in the former mCAC with a composite piston composed of the Cu-Be and ceramic cylinders reduces the background magnetization significantly smaller at low temperatures, enabling more precise magnetic measurements at low temperatures. A second modification to the mCAC is the utilization of a ceramic anvil with a hollow in the center of the culet surface. High pressures up to 5 GPa were generated with the "cupped ceramic anvil" with the culet size of 1.0 mm.

  2. Improvement in performance of dye-sensitized solar cells with porous TiO2 electrodes using squid ink particles

    Science.gov (United States)

    Matsuura, Toshihiko; Nagai, Sakura; Ogasawara, Kou; Minato, Ken-ichi; Sakai, Mitsuo; Ueno, Takashi

    2016-06-01

    A potentially appealing alternative to the traditional fabrication process of TiO2 film electrodes for dye-sensitized solar cells (DSSCs) was presented by utilizing water-soluble TiO2 composite pastes containing size-controlled ink particles (SIPs) isolated from the squid. The mixture ratios of SIPs in the paste formulations affected the photoelectric conversion efficiency (PCE). The highest PCE was achieved when the mixture ratio of SIPs was 20%. The process is highly reproducible and leads to a 35% increase in PCE compared with that in the DSSC without SIP addition. The utilization of SIPs in the fabrication of TiO2 film electrodes enhanced the performance of DSSCs.

  3. A new measurement tool for characterization of superconducting rf accelerator cavities using high-performance LTS SQUIDs

    Energy Technology Data Exchange (ETDEWEB)

    Vodel, W [Friedrich-Schiller-University Jena, Helmholtzweg 5, 07743 Jena (Germany); Neubert, R [Friedrich-Schiller-University Jena, Helmholtzweg 5, 07743 Jena (Germany); Nietzsche, S [Friedrich-Schiller-University Jena, Helmholtzweg 5, 07743 Jena (Germany); Seidel, P [Friedrich-Schiller-University Jena, Helmholtzweg 5, 07743 Jena (Germany); Knaack, K [DESY Hamburg (Germany); Wittenburg, K [DESY Hamburg (Germany); Peters, A [Heidelberger Ionenstrahl-Therapiezentrum, Heidelberg (Germany)

    2007-11-15

    This paper presents a new system to measure very low currents in an accelerator environment, using a cryogenic current comparator (CCC). In principle a CCC is a conventional current transformer using the high-performance SQUID technology to sense the magnetic fields caused by the beam current. Since the system is sensitive on a pA level, it is an optimum device to detect dark currents of superconducting cavities. The system presented here is designed for the test facilities of the superconducting accelerator modules for the European XFEL at the Deutsches Elektronen-Synchrotron (DESY) in Hamburg. Measurements in a quiet environment showed that an intrinsic noise level of the CCC of 40 pA Hz{sup -1/2} could be achieved.

  4. Gradiômetros supercondutores acoplados a SQUIDs e sua aplicação em biomagnetismo.

    OpenAIRE

    Antonio Carlos Oliveira Bruno

    1990-01-01

    O objetivo desta tese foi o estudo da detecção de campos magnéticos fracos através da utilização de gradiômetros supercondutores acoplados à SQUIDs e sua aplicação ao biomagnetismo. Um novo modelo teórico para descrição do gradiômetro foi desenvolvido com a obtenção da sua função de transferência espacial. Através desta função de transferência a atuação do gradiômetro sobre os sinais detectados pode ser quantificada. Além disso, foi desenvolvido para a medida experimental da função de transfe...

  5. Demonstration of a scalable frequency-domain readout of metallic magnetic calorimeters by means of a microwave SQUID multiplexer

    Directory of Open Access Journals (Sweden)

    Sebastian Kempf

    2017-01-01

    Full Text Available We report on the first demonstration of a scalable GHz frequency-domain readout of metallic magnetic calorimeters (MMCs using a 64 pixel detector array that is read out by an integrated, on-chip microwave SQUID multiplexer. The detector array is optimized for detecting soft X-ray photons and the multiplexer is designed to provide a signal rise time τrise<400ns and an intrinsic energy sensitivity ϵ<30h. This results in an expected energy resolution ΔEFWHM<10eV. We measured a signal rise time τrise as low as 90ns and an energy resolution ΔEFWHM as low as 50eV for 5.9keV photons. The rise time is about an order of magnitude faster compared to other multiplexed low-temperature microcalorimeters and close to the intrinsic value set by the coupling between electron and spins. The energy resolution is degraded with respect to our design value due to a rather low intrinsic quality factor of the microwave resonators that is caused by the quality of the Josephson junction of the associated rf-SQUID as well as an elevated chip temperature as compared to the heat bath. Though the achieved energy resolution is not yet compatible with state-of-the-art single-channel MMCs, this demonstration of a scalable readout approach for MMCs in combination with the full understanding of the device performance showing ways how to improve represents an important milestone for the development of future large-scale MMC detector arrays.

  6. Variability of Suitable Habitat of Western Winter-Spring Cohort for Neon Flying Squid in the Northwest Pacific under Anomalous Environments.

    Science.gov (United States)

    Yu, Wei; Chen, Xinjun; Yi, Qian; Chen, Yong; Zhang, Yang

    2015-01-01

    We developed a habitat suitability index (HSI) model to evaluate the variability of suitable habitat for neon flying squid (Ommastrephes bartramii) under anomalous environments in the Northwest Pacific Ocean. Commercial fisheries data from the Chinese squid-jigging vessels on the traditional fishing ground bounded by 35°-45°N and 150°-175°E from July to November during 1998-2009 were used for analyses, as well as the environmental variables including sea surface temperature (SST), chlorophyll-a (Chl-a) concentration, sea surface height anomaly (SSHA) and sea surface salinity (SSS). Two empirical HSI models (arithmetic mean model, AMM; geometric mean model, GMM) were established according to the frequency distribution of fishing efforts. The AMM model was found to perform better than the GMM model. The AMM-based HSI model was further validated by the fishery and environmental data in 2010. The predicted HSI values in 1998 (high catch), 2008 (average catch) and 2009 (low catch) indicated that the squid habitat quality was strongly associated with the ENSO-induced variability in the oceanic conditions on the fishing ground. The La Niña events in 1998 tended to yield warm SST and favorable range of Chl-a concentration and SSHA, resulting in high-quality habitats for O. bartramii. While the fishing ground in the El Niño year of 2009 experienced anomalous cool waters and unfavorable range of Chl-a concentration and SSHA, leading to relatively low-quality squid habitats. Our findings suggest that the La Niña event in 1998 tended to result in more favorable habitats for O. bartramii in the Northwest Pacific with the gravity centers of fishing efforts falling within the defined suitable habitat and yielding high squid catch; whereas the El Niño event in 2009 yielded less favorable habitat areas with the fishing effort distribution mismatching the suitable habitat and a dramatic decline of the catch of O. bartramii. This study might provide some potentially valuable

  7. Variability of Suitable Habitat of Western Winter-Spring Cohort for Neon Flying Squid in the Northwest Pacific under Anomalous Environments.

    Directory of Open Access Journals (Sweden)

    Wei Yu

    Full Text Available We developed a habitat suitability index (HSI model to evaluate the variability of suitable habitat for neon flying squid (Ommastrephes bartramii under anomalous environments in the Northwest Pacific Ocean. Commercial fisheries data from the Chinese squid-jigging vessels on the traditional fishing ground bounded by 35°-45°N and 150°-175°E from July to November during 1998-2009 were used for analyses, as well as the environmental variables including sea surface temperature (SST, chlorophyll-a (Chl-a concentration, sea surface height anomaly (SSHA and sea surface salinity (SSS. Two empirical HSI models (arithmetic mean model, AMM; geometric mean model, GMM were established according to the frequency distribution of fishing efforts. The AMM model was found to perform better than the GMM model. The AMM-based HSI model was further validated by the fishery and environmental data in 2010. The predicted HSI values in 1998 (high catch, 2008 (average catch and 2009 (low catch indicated that the squid habitat quality was strongly associated with the ENSO-induced variability in the oceanic conditions on the fishing ground. The La Niña events in 1998 tended to yield warm SST and favorable range of Chl-a concentration and SSHA, resulting in high-quality habitats for O. bartramii. While the fishing ground in the El Niño year of 2009 experienced anomalous cool waters and unfavorable range of Chl-a concentration and SSHA, leading to relatively low-quality squid habitats. Our findings suggest that the La Niña event in 1998 tended to result in more favorable habitats for O. bartramii in the Northwest Pacific with the gravity centers of fishing efforts falling within the defined suitable habitat and yielding high squid catch; whereas the El Niño event in 2009 yielded less favorable habitat areas with the fishing effort distribution mismatching the suitable habitat and a dramatic decline of the catch of O. bartramii. This study might provide some potentially

  8. Improvement design and experiment of squid jigging machine%鱿鱼钓机的改进设计与试验

    Institute of Scientific and Technical Information of China (English)

    刘健; 黄洪亮; 潘陈强; 王长根; 王平; 王强; 李灵智; 吴越

    2014-01-01

    为提升鱿鱼钓机国产化水平,该文针对鱿鱼钓机的动力系统、控制系统、保护装置及控制面板等关键部件进行了改进设计。动力系统采用交流伺服驱动器结合交流伺服永磁同步电机的运行模式。控制系统包括放线程序、诱钓程序收线程序和收工程序子控制系统。显示操作面板采用数码管显示器和图文显示屏相结合的方式,可根据不同海况和钓捕要求调节作业参数。在保护装置方面设计了智能防过载功能,0位(重锤位于海平面的位置)及上限位置保护和缺相报警措施。海上测试结果表明试验机运行稳定,试验机20 d渔获量为2493 kg,试验机渔获量与对照机无显著性差异(P>0.05)。%The squid resource is rich and widely distributed, which is an important economic cephalopod fishery resources. Squid jigging fishery is one of pillar industry in China ocean fisheries. There are 2 kinds of operation form in squid jigging fishery, one is hand line and the other is squid jigging machine. As a major component of squid jigging fishery, the squid jigging machine relies on import currently and the domestic research is still in a primary stage. To enhance the localization level of squid jigging machine, the improved design of power system, control system, control panel and protection device which are the main parts of squid jigging machine are discussed in detail. The overall structure is consisted of machine case and roller. The motor, reducer, control power, intelligent module, controller and a driver with protection circuit are installed in the machine case. The control power, intelligent module and driver connect with the controller through socket outlet, which is convenient for components maintenance and replacement. The power system of squid jigging machine adopts AC servo drive combined with AC servo permanent magnet synchronous motor. The encoder installed on the motor shaft back

  9. 乌贼墨及其活性多糖的研究进展%Research progress of squid ink and its polysaccharide

    Institute of Scientific and Technical Information of China (English)

    谷毅鹏; 尚江华; 陶叶杏; 刘华忠

    2015-01-01

    ABSTRACT:At present, it is an important way to study the development of natural medicine via searching for active substances from marine life. Squid is an abundant marine animal and its ink is wastes from squid processing. However, Squid ink is a kind of marine active substance with great potential on its physiological activities, such as hemostasis, antibacterial, enhance immunity, antitumor and antioxidation. Squid ink polysaccharide is the most important active ingredient isolated from squid ink, which has good effects of antioxidant, antitumor, antichemotherapy and enhanced immunity, etc. The researches on bioactive constituents in squid ink provide not only high value utilization way for squid processing wastes, but also new resources for development of clinical medicine and health food, which demonstrate great significance to expand the source of medicine and make full use of marine resources, thus, attract the extensive attention from scientific researchers. In this review, we summarized the recent research progress about squid ink and its polysaccharide at home and abroad, in terms of their physical and chemical properties, biological activity and clinical application, and proposed the future research direction according to their research characteristic and application prospects.%目前,从海洋生物中寻找活性物质,是研究开发天然药物的一个重要方向。乌贼是丰富易得的海洋生物,而乌贼墨是乌贼加工中的废弃物,它作为一种极具潜力的海洋活性物质,具有止血、抗菌、增强免疫、抗肿瘤、抗氧化等多种生理活性。乌贼墨多糖就是从乌贼墨中分离出的一种主要活性成分,在抗氧化、抗肿瘤、抗化疗、增强免疫等功能活性方面均表现出了良好的作用效果。通过对乌贼墨中生物活性成分的研究,不仅为乌贼加工废弃物提供了高值化利用途径,也为开发临床医药、保健食品提供了新的资源,对扩

  10. Investigations for low noise cooling by means of a pulse tube cooler for highly sensitive SQUID magnetometers from high temperature superconductors

    CERN Document Server

    Lienerth, C

    2000-01-01

    110fT/[Root]Hz at 10 Hz. For the discret peaks at the working frequency the vibration compensation is capable of reducing the cooler-generated peaks in the field noise spectrum by a factor of the order of 4. This noise level is low enough for applications such as nondestructive evaluation of materials. For identifying the origin of the remaining disturbances, one has to consider in addition to the residual vibrations also temperature oscillations and oscillating fields from eddy current at the SQUID location. The commercial acceptance of superconducting applications is closely associated with the availability of appropriate cryocoolers that enable continuous operation without the need to re-fill liquid cryogens. For cooling of highly-sensitive HT-SQUID sensors the cryocooler has to meet rather severe demands concerning interference from the cooler itself. In particular, cooler-generated noise from electromagnetic interference (EMI), mechanical vibrations and temperature fluctuations should be below the intrin...

  11. The complete mitochondrial genome of the cryptic "lineage A" big-fin reef squid, Sepioteuthis lessoniana (Cephalopoda: Loliginidae) in Indo-West Pacific.

    Science.gov (United States)

    Hsiao, Chung-Der; Shen, Kang-Ning; Ching, Tzu-Yun; Wang, Ya-Hsien; Ye, Jeng-Jia; Tsai, Shiou-Yi; Wu, Shan-Chun; Chen, Ching-Hung; Wang, Chia-Hui

    2016-07-01

    In this study, the complete mitogenome sequence of the cryptic "lineage A" big-fin reef squid, Sepioteuthis lessoniana (Cephalopoda: Loliginidae) has been sequenced by the next-generation sequencing method. The assembled mitogenome consists of 16,605 bp, which includes 13 protein-coding genes, 22 transfer RNAs, and 2 ribosomal RNAs genes. The overall base composition of "lineage A" S. lessoniana is 37.5% for A, 17.4% for C, 9.1% for G, and 35.9% for T and shows 87% identities to "lineage C" S. lessoniana. It is also noticed by its high T + A content (73.4%), two non-coding regions with TA tandem repeats. The complete mitogenome of the cryptic "lineage A" S. lessoniana provides essential and important DNA molecular data for further phylogeography and evolutionary analysis for big-fin reef squid species complex.

  12. DC SQUID, NQUID and nanoSQUID; “The prediction of behaviors on the base of analytic results of the Fokker-Planck equation”

    Directory of Open Access Journals (Sweden)

    M Eatesami

    2009-08-01

    Full Text Available  By defining the loop inductance for NQUID and considering sinusoidal Fourier series for the current-phase relations of its nanowires and replacing two Langevin equations with one two-dimensional Fokker-Planck equation, we have obtained analytical relations for the characteristics of the asymmetric NQUID. On the other hand for DC SQUIDs and nanoSQUID, we have to consider simultaneously the effects of the deviation of the current-phase relation from Is(θα sinθ , the effects of fluctuations and noises and also the effects of asymmetry (usually two junctions have some differences on the current-voltage characteristic. Therefore various considerations necessitate more accurate analytical formulation and more theoretical predictions .

  13. Magnetization measurements of non-centrosymmetric superconductor LaPt3Si: Construction of low temperature magnetometers with the SQUID and Hall sensor

    Science.gov (United States)

    Fujisawa, Takumi; Yamaguchi, Akira; Motoyama, Gaku; Kawakatsu, Daichi; Sumiyama, Akihiko; Takeuchi, Tetsuya; Settai, Rikio; Ōnuki, Yoshichika

    2015-04-01

    We report magnetization of a non-centrosymmetric superconductor, LaPt3Si below 0.6 K up to 200 Oe. The home-made SQUID and Hall sensor magnetometers that operate below 1 K were constructed for this purpose. Although the SQUID magnetometer is more sensitive than the Hall sensor’s one, it was found not to work correctly for the rapid magnetization change of LaPt3Si below 0.4 K. The Hall sensor magnetometer, in contrast, can properly detect magnetization jumps in the M-H curve of the superconducting state. The observed flux jumps are probably related to the interfusion of the mixed state of the LaPt3Si that is observed in the μSR measurements.

  14. A comparison of fishery biology of jumbo flying squid, Dosidicus gigas outside three Exclusive Economic Zones in the Eastern Pacific Ocean

    Science.gov (United States)

    Liu, Bilin; Chen, Xinjun; Yi, Qian

    2013-05-01

    Although many studies on the fishery biology of jumbo flying squid, Dosidicus gigas, have been conducted in the coastal areas within Exclusive Economic Zones (EEZs) of various countries due to its commercial and ecological importance, limited biological information is available from waters outside these EEZs. In this paper, we examined D. gigas fishery biology from waters outside Chilean, Peruvian and Costa Rican EEZs, based on the fishery data collected by Chinese jigging vessels during 2006 to 2010. The dominant mantle lengths of D. gigas were 350-450 mm, 250-400 mm and 250-350 mm outside Chilean, Peruvian and Costa Rican EEZs, respectively. Size structure analysis show that a medium-sized group existed mostly in the waters outside the Chilean and Peruvian EEZs, whereas a small-sized group occurred mainly in the waters outside the Costa Rican EEZ. The longevity of the squid outside the Costa Rican EEZ was less than 10 months, while most of those outside Chilean and Peruvian EEZs were about 1-1.5 years and very few large individuals were 1.5-2 years old. A higher percentage of mature individuals existed outside Costa Rican EEZ implying the region as a potential spawning ground, while lower proportions of mature squid outside the Peruvian and Chilean EEZs indicated that spawning may be occurring outside our study area. Spatial differences in sizes at maturity of the squid are thought to be result from different environmental factors especially different temperature and nutrition among the three areas. Stomach-content analysis showed that cannibalism was important in the diet of D. gigas. Stress generated by jigging may increase the incidence of cannibalism.

  15. A comparison of fishery biology of jumbo flying squid,Dosidicus gigas outside three Exclusive Economic Zones in the Eastern Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    LIU Bilin; CHEN Xinjun; YI Qian

    2013-01-01

    Although many studies on the fishery biology of jumbo flying squid,Dosidicus gigas,have been conducted in the coastal areas within Exclusive Economic Zones (EEZs) of various countries due to its commercial and ecological importance,limited biological information is available from waters outside these EEZs.In this paper,we examined D.gigas fishery biology from waters outside Chilean,Peruvian and Costa Rican EEZs,based on the fishery data collected by Chinese jigging vessels during 2006 to 2010.The dominant mantle lengths of D.gigas were 350-450 mm,250-400 mm and 250-350 mm outside Chilean,Peruvian and Costa Rican EEZs,respectively.Size structure analysis show that a medium-sized group existed mostly in the waters outside the Chilean and Peruvian EEZs,whereas a small-sized group occurred mainly in the waters outside the Costa Rican EEZ.The longevity of the squid outside the Costa Rican EEZ was less than 10 months,while most of those outside Chilean and Peruvian EEZs were about 1-1.5 years and very few large individuals were 1.5-2 years old.A higher percentage of mature individuals existed outside Costa Rican EEZ implying the region as a potential spawning ground,while lower proportions of mature squid outside the Peruvian and Chilean EEZs indicated that spawning may be occurring outside our study area.Spatial differences in sizes at maturity of the squid are thought to be result from different environmental factors especially different temperature and nutrition among the three areas.Stomach-content analysis showed that cannibalism was important in the diet of D.gigas.Stress generated by jigging may increase the incidence of cannibalism.

  16. Ethogram analysis reveals new body patterning behavior of the tropical arrow squid Doryteuthis plei off the São Paulo Coast.

    Science.gov (United States)

    Postuma, Felippe A; Gasalla, Maria A

    2015-10-01

    Squids can express several body patterns, aided by a variety of visual signals that are produced by chromatophore organs. However, for several squid species, body patterning behavior during reproductive activity is still not completely understood. For example, what are the specific patterning changes and other visual signals, how do they appear, and how long do they last? To test the hypothesis that distinct chromatic components appear at different durations on the skin of the tropical arrow squid Doryteuthis plei in the Southern Hemisphere, we identified and described its body patterning behavior. Specimen squids were obtained from off the South Brazil Bight, near the coast of the São Paulo shelf. Animals were maintained and monitored in circular tanks for 62 d over six observation periods, from 2011 through 2013. An ethogram was constructed showing 19 chromatic, 5 locomotor, and 12 postural components, or body patterns, associated with reproductive behavior. New chromatic components (i.e., those not yet reported in the North Atlantic D. plei species), particularly those linked to female sexual maturity, were observed. A postural component, the "J-Posture," linked to defenses and alarm, also was noted. The average time spent for "light" components was 32 s. The corresponding "dark" components had an average duration of 28 s. Females displayed the chromatic components related to calm behavior longer than males. However, males appeared to be more dedicated to disputes over resources, and used rapid, miscellaneous visual signaling. In conclusion, new basic types of body patterns are described for D. plei. The repertoire of chromatic components reported in the ethogram is, to our knowledge, the first record for D. plei of the Southern Hemisphere.

  17. Evaluation of jumbo squid (Dosidicus gigas byproduct hydrolysates obtained by acid-enzymatic hydrolysis and by autohydrolysis in practical diets for Pacific white shrimp (Litopenaeus vannamei

    Directory of Open Access Journals (Sweden)

    Mayra Lizett González-Félix

    2014-09-01

    Full Text Available The marine bioprocessing industry offers great potential to utilize byproducts for fish meal replacement in aquafeeds. Jumbo squid is an important fishery commodity in Mexico, but only the mantle is marketed. Head, fins, guts and tentacles are discarded in spite of being protein-rich byproducts. This study evaluated the use of two jumbo squid byproduct hydrolysates obtained by acid-enzymatic hydrolysis (AEH and by autohydrolysis (AH as ingredients in practical diets for shrimp. The hydrolysates were included at levels of 2.5 and 5.0% of the diet dry weight in four practical diets, including a control diet without hydrolysate. Shrimp growth and survival were not significantly affected by the dietary treatments. Postharvest quality of abdominal muscle was evaluated in terms of proximate composition and sensory evaluation. Significantly higher crude protein was observed in the muscle of shrimp fed the highest hydrolysate levels, AH 5% (204.8 g kg- 1 or AEH 5% (201.3 g kg- 1. Sensory analysis of cooked muscle showed significant differences for all variables evaluated: color, odor, flavor, and firmness. It was concluded that Jumbo squid byproducts can be successfully processed by autohydrolysis or acid-enzymatic hydrolysis, and that up to 5.0% of the hydrolysates can be incorporated into shrimp diets without affecting growth or survival.

  18. Gladius and statolith as tools for age and growth studies of the squid Loligo plei (Teuthida: Loliginidae off southern Brazil

    Directory of Open Access Journals (Sweden)

    José Angel Alvarez Perez

    2006-09-01

    Full Text Available Statolith and gladius were investigated for their suitability as tools for age and growth studies in the loliginid squid Loligo plei off southern Brazil. Statoliths when polished, revealed a series of concentric increments deposited around a nucleus. Consistent increment counts covered the squid's entire life-time and could be considered suitable for individual age estimation. Growth increments were observed on the dorsal surface as delimited by consecutive marks formed during low growth periods. Because early growth was masked during chitin deposition, total increment counts underestimated individual age. Gladius growth was highly correlated with somatic growth, and gladius increments could be used to reconstruct individual growth histories. Both statolith and gladius increments were deposited with the same, possibly daily, periodicity. It could be inferred that L. plei off southern Brazil might live up to around nine months of age.Foi avaliada a viabilidade do estatólito e do gladius como ferramentas para estudos de idade e crescimento da lula loliginídea Loligo plei no sul do Brasil. Estatólitos são estruturas calcificadas que, após polimento, revelaram uma serie de incrementos concêntricos depositados em torno de um núcleo. Contagens consistentes desses incrementos cobriram toda a vida do animal e puderam ser consideradas apropriadas para a estimativa de idade desse organismo. O gladius é a concha interna que cresce pela deposição longitudinal de camadas de quitina. Incrementos foram observados na superfície dorsal, delimitados por consecutivas marcas formadas durante períodos de crescimento lento. Ao longo da deposição de quitina o crescimento do início da vida é progressivamente mascarado fazendo com que as contagens de incrementos totais subestimem a idade da lula. Devido ao crescimento do gladius correlacionar-se fortemente com o crescimento somático, os incrementos puderam ser utilizados para a reconstrução do

  19. 采用空穴阻挡层提高有机太阳电池效率的研究%Adsorption Influencing Factors and Isotherms of Squid Melanin on Pb^2+ and Cr^6+

    Institute of Scientific and Technical Information of China (English)

    鲁婷婷; 林琳; 褚梦思; 汪盼盼; 黄乾; 宋茹

    2012-01-01

    为研究BCP对有机太阳电池的影响,制备了含BCP层的体相异质结电池,器件结构为:ITO/PEDOT:PSS/P3HT+PCBM/BCP/LiF/Al。结果表明:BCP层起到了空穴阻挡和电子传输的作用,器件性能随着BCP层厚度的不同而变化,当BCP厚度为6nm时,其性能最好。%In this study, squid melanin was used as adsorbent to remove of Pb^2+ and Cr^6+ from aqueous solutions, the adsorption factors including squid melanin content, adsorption time, adsorption temperature and solution pH were investigated, as well as the adsorption isotherms were analyzed. Results showed that the added squid melanin effectively adsorbed Pb^2+ and Cr^6+ in aqueous solutions. The removal rates of Pb^2+ and Cr^6+ were above 85.00% after adsorption of 15 min by squid melain. In addition, the removal rate of Pb^2+ decreased with the increased adsorption temperatures, whereas, the maximum adsorption of Cr^6+ was found at 35℃. The low adsorption capacity of squid melanin on Pb^2+ was observed at solution pH of 5.0, and the effective solution pH for Cr^6+ removal was in the range of 4.0 to 6.0. Furthermore, results of adsorption isotherms revealed that the adsorption characteristic of squid melanin on Cr^6+ fitted well to Langmuir and Freundlich models. By comparison, the adsorption behavior of squid melanin on Pb^2+ only had a good correlation with the Langmuir isotherm.

  20. 鱿鱼丝不同包装条件下细菌学研究%Studies on Bacterium of Shredded Squid under Different Packaging Conditions

    Institute of Scientific and Technical Information of China (English)

    吴少杰; 朱强; 吕玲玲; 马桂珍; 王淑军; 文贞花

    2011-01-01

    [目的]探索鱿鱼丝贮藏期间微生物学特征.[方法]采用食品化学、微生物学和分子生物学手段,研究真空包装和普通包装条件下鱿鱼丝理化性质、微生物性质及其变化规律.[结果]在贮藏期间,鱿鱼丝水分含量为22%~26%,水分活度(Aw)为0.55~0.58,水分下降及挥发性盐基氮(T-VBN)上升幅度均低于10%,总菌数和耐热菌数分别增加10倍左右;相比普通包装,真空包装鱿鱼丝失水速度慢,挥发性盐基氮生成少,微生物繁殖少;在鱿鱼丝中分离到12株细菌,属于节杆菌属、游动微茼属、不动杆菌属等.[结论]真空包装有利于保持鱿鱼丝口感、品质,并能抑制微生物生长繁殖;鱿鱼丝中主要存在节杆菌、游动微菌、不动杆菌等细菌,今后应加强对这些微生物的控制.%[ Objective ] The research aimed to explore microbiology characteristics of shredded squid during storage. [ Method ] By food chemistry, microbiology and molecule biology means, the physicochemical and microbe properties of shredded squid, and their change trend under conditions of vacuum packaging and common packaging were studied. [ Result] During storage, the water content of shredded squid was 22% -26% and Aw was 0. 55 -0.58. Moisture descend and T-VBN ascend extent were under 10%. And total microbes and heat-resisting microbes increased around 10 times. Comparing with common packaging, vacuum packaging shredded squid had a lower moisture losing velocity and fewer T-VBN creating quantity and microbe breeding quantity. Altogether 12 bacteria were separated from shredded squid, and were preliminarily identified as genus Arthrobacter, Planomicrobiurn and Acinetobacter, etc. [ Conclusion] Vacuum packaging was in favor of keeplng shredded squid taste and quality and of restraining microbe grow and breed. Shredded squid mainly had microbe of Arthrobacter, Planomicrobium and Acinetobacter, which should be controlled strictly in the future.

  1. Niobium nano-SQUIDs based on sub-micron tunnel junction fabricated by three-dimensional Focused Ion Beam sculpting

    Science.gov (United States)

    Fretto, M.; Enrico, E.; De Leo, N.; Boarino, L.; Lacquaniti, V.; Granata, C.; Russo, R.; Vettoliere, A.

    2014-05-01

    A three dimensional nano-SQUID (Superconducting Quantum Interference Device) has been realized in a vertical configuration (with the loop in the same plane of Josephson Tunneling Junctions, JTJs). The loop area is 0.25 μm2 corresponding to a modulation period of about 5 mT, the square JTJs have a side length of 0.3 μm. Josephson junction's fabrication is carried out combining optical lithography to pattern trilayer and three dimensional (3D) Focused Ion Beam (FIB) sculpting technique to define the junctions' and the loop's areas. Two different ion etching processes were performed, perpendicular and parallel to the multilayer, resulting in a precise 3D structure. Finally, a standard anodization was performed to eliminate the unstructured surface material generated by the high energetic ion beam assuring high quality junctions. Electric transport characteristics of the nanodevice measured at T = 4.2 K are reported, in particular the current-voltage characteristics and critical current vs external magnetic field. The high modulation depth of the critical current (up to 70% of the Ic at zero magnetic flux) and the device reliability are very encouraging in view of nanoscience applications.

  2. ZFC/FC of oriented magnetic material in the Solenopsis interrupta head with antennae: characterization by FMR and SQUID.

    Science.gov (United States)

    Abraçado, Leida G; Esquivel, D M S; Wajnberg, Eliane

    2012-09-01

    Ferromagnetic resonance and SQUID magnetometry have been used to study magnetic material in the head with antennae, thorax, and abdomen of Solenopsis interrupta ants. The temperature dependence of the head with antennae using both techniques was measured. Room-temperature spectra and saturation magnetization were used to compare the magnetic material amount in the ant body parts. Both techniques show that the highest magnetic material fraction is in the head with antennae. The ordering temperature is observed at 100 ± 20 K for the ferromagnetic resonance spectra HF component. The estimated magnetic anisotropy constant K and g-values at room temperature are in good agreement with magnetite, supporting this material as the main magnetic particle constituent in the Solenopsis interrupta head with antenna. Particle diameters of 26 ± 2 nm and smaller than 14 nm were estimated. This work suggests that the head with antenna of the Solenopsis interrupta ant contains organized magnetic material and points to it as a good candidate as a magnetic sensor.

  3. A noninvasive method to determine the fate of Fe(3O(4 nanoparticles following intravenous injection using scanning SQUID biosusceptometry.

    Directory of Open Access Journals (Sweden)

    Wei-Kung Tseng

    Full Text Available Magnetic nanoparticles (MNPs of Fe(3O(4 have been widely applied in many medical fields, but few studies have clearly shown the outcome of particles following intravenous injection. We performed a magnetic examination using scanning SQUID biosusceptometry (SSB. Based on the results of SSB analysis and those of established in vitro nonmagnetic bioassays, this study proposes a model of MNP metabolism consisting of an acute metabolic phase with an 8 h duration that is followed by a chronic metabolic phase that continues for 28 d following MNP injection. The major features included the delivery of the MNPs to the heart and other organs, the biodegradation of the MNPs in organs rich with macrophages, the excretion of iron metabolites in the urine, and the recovery of the iron load from the liver and the spleen. Increases in serum iron levels following MNP injection were accompanied by increases in the level of transferrin in the serum and the number of circulating red blood cells. Correlations between the in vivo and in vitro test results indicate the feasibility of using SSB examination for the measurement of MNP concentrations, implying future clinical applications of SSB for monitoring the hematological effects of MNP injection.

  4. 鱿鱼皮胶原蛋白肽生理功能的研究进展%Research Progress of the Bioactive Functions of Proteins and Peptides from Squid Skin

    Institute of Scientific and Technical Information of China (English)

    夏克东; 刘振锋; 田少君; 马燕

    2015-01-01

    Squid skin contains low fat and high protein,and the level of proteins from squid skin is the same as squid body.Its rich nutritional value has been commonly recognized.This paper mainly introduces the study about the bioactive functions of squid skin peptide,such as antioxidant activity,ACE inhibitory activity,inhibition of tumor cell activity and anti-aging active suppression.These will provide some reference for the exploitation and application of proteins and peptides extracted from squid skin.%鱿鱼皮是一种高蛋白低脂肪的物质,蛋白组成与本体基本一致,而且胶原蛋白含量相对较高,其丰富的营养价值已经被大家所认可.主要介绍了国内外对鱿鱼皮蛋白肽的生物活性功能,如抗氧化活性、ACE抑制活性、抑制肿瘤细胞活性以及抗衰老等的研究,为鱿鱼皮蛋白肽的开发利用提供参考.

  5. Functional Properties of Enzymatic Hydrolysates from Squid Skin%鱿鱼皮酶解产物的功能特性

    Institute of Scientific and Technical Information of China (English)

    林燕; 王鸿飞; 李和生; 刘飞; 毛方华

    2011-01-01

    目的:研究鱿鱼皮酶解产物的功能特性.方法:根据前期实验所得最适酶解工艺,以中性蛋白酶酶解鱿鱼皮,产物经离心、过滤、冻干,研究其抗氧化活性和加工功能特性.抗氧化活性采用·OH、O2-·清除及Fe2+螯合、FRAP体系进行评价.加工功能特性包括溶解性、稳定性、起泡性及乳化性的测定.结果:鱿鱼皮酶解产物具有良好的·OH清除能力及Fe2+螯合能力,在试验范围内分别达到84.5%和89.9%;对O2-·清除能力一般,仅53.1%.由于样品纯度问题,各体系抗氧化能力及总还原力与L-抗坏血酸相比有明显差距.此外,在加工功能特性方面,除热稳定性及泡沫稳定性不甚理想,仅80.3%和54.2%外,其它特性均良好.其中溶解性97%,冷藏稳定性89.9%,起泡性240%,乳化性808.8 m2/g及乳化稳定性13.8 min.结论:鱿鱼皮来源广泛,价格低廉,其酶解产物具有较好的抗氧化活性及加工功能特性,在功能食品方面具有较大的应用价值.%Objective: To study the functional properties of enzymatic hydrolysates from squid skin. Methods:The squid skin (Illex argentinus) was hydrolyzed by neutral protease. The optimum hydrolysis conditions were determined by orthogonal experiment design. The optimum conditions were temperature 40 t, enzyme dosage 10 000 U/g, concentration of substrate 2%, Ph 8.5, and time 5 h, from which the hydrolyzed degree was 19.7%. By centrifugation,filtration and lyophilization,functional properties including antioxidant activity, solubility, stability, foaming capability, foaming stability, emulsifying capacity and emulsion stability of squid skin enzymatic hydrolysates were investigated. Result: The squid skin enzymatic hydrolysates had a good scavenging capability of -OH and chelating activity of Fe2+, which were 84.5% and 89.9% respectively within test range. Scavenging -OH ability was not very ideal, which only had 53.1%. Every assay of antioxidant ability and

  6. The Evaluation of a Squid-Based Non-Contact Magnetic Nde Technique for Application to the Inspection of Offshore Steel Structures

    Science.gov (United States)

    Evanson, S.

    1988-12-01

    Available from UMI in association with The British Library. Requires signed TDF. Conventional methods of Non Destructive Evaluation (NDE) for the detection of surface-breaking defects in steel structures require intimate contact with the test site. This is a serious limitation in offshore inspection where the structure may be covered with tenacious marine contamination up to 0.5m thick. A method of magnetic examination to detect surface-breaking defects at distances, from a steel specimen, in excess of 10cm is reported. A persistent mode superconducting solenoid generates a DC magnetic field perpendicular to the specimen surface. The spatial distortion of this field by surface defects is detected using a SQUID coupled to a novel planar gradiometer, coaxial with the solenoid. DC operation means detection is unaffected by electrically conductive surface coatings. A point defect is represented by an equivalent magnetic dipole and a long defect by a line dipole with a uniformly distributed magnetic moment. Mathematical models for the response of a gradiometer to magnetic dipole sources are used to design a suitable planar gradiometer. Theoretical and experimental data demonstrate the superior performance of this design compared with a conventional second order gradiometer of the type available commercially. The construction of a system for acquisition and computer processing of data from the examination of steel specimens is discussed. Extensive tests were conducted on flat steel plates containing ideal surface defects and good agreement is found with the defect models. The major limitation on defect resolution is a background field associated with the magnetised steel plate. Background components of low spatial frequency are reduced by balancing the gradiometer, further improvement in resolution is achieved by applying band pass digital filters to the SQUID output. A SQUID system offers considerable promise for remote detection of surface defects in plane steel

  7. Jumbo squid (Dosidicus gigas) mantle collagen: extraction, characterization, and potential application in the preparation of chitosan-collagen biofilms.

    Science.gov (United States)

    Uriarte-Montoya, Mario Hiram; Arias-Moscoso, Joe Luis; Plascencia-Jatomea, Maribel; Santacruz-Ortega, Hisila; Rouzaud-Sández, Ofelia; Cardenas-Lopez, Jose Luis; Marquez-Rios, Enrique; Ezquerra-Brauer, Josafat Marina

    2010-06-01

    Collagen-based biomaterials have been widely used due to its binding capabilities. However the properties and potential use of new collagen sources are still under investigation. Fish by-products are an excellent source of collagen. Thus, acid-soluble collagen (ASC) was extracted, and biochemical and physicochemically characterized from one under-utilized specie, jumbo squid (Dosidicus gigas). In addition, commercial chitosan (95-50%)-ASC (5-50%) blend films were successfully prepared by casting, and characterized by infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The molecular masses of the ASC subunits were about 190kDa, 110kDa, and 97kDa, the content of proline and hydroxyproline was 10.9% and 2.8%, respectively. The FT-IR and nuclear magnetic resonance spectra ((1)H NMR) confirmed collagen peptidic crosslinks, and one endothermic peak was found at 119 degrees C. The FT-IR spectrum showed that chitosan and ASC remain linked into the films mainly due to hydrogen bonding. The 85:15 (chitosan:ASC) ratio was selected for its thermal and mechanical analyses. The thermograms of this film indicated the presence of two peaks, one at 87-98 degrees C and the other at 142-182 degrees C. The chitosan:ASC blend produced a transparent and brittle film, with high percentage of elongation at break, and low tensile strength in comparison to chitosan films. D. gigas mantle might be useful as a new source of plasticizer agent in the preparation of biofilms in composites with chitosan.

  8. Differential expression of the FMRF gene in adult and hatchling stellate ganglia of the squid Loligo pealei

    Directory of Open Access Journals (Sweden)

    J. Peter H. Burbach

    2013-12-01

    The giant fiber system of the squid Loligo pealei mediates the escape response and is an important neurobiological model. Here, we identified an abundant transcript in the stellate ganglion (SG that encodes a FMRFamide precursor, and characterized FMRFamide and FI/LRF-amide peptides. To determine whether FMRFamide plays a role in the adult and hatchling giant fiber system, we studied the expression of the Fmrf gene and FMRFamide peptides. In stage 29 embryos and stage 30 hatchlings, Ffmr transcripts and FMRFamide peptide were low to undetectable in the SG, in contrast to groups of neurons intensely expressing the Fmrf gene in several brain lobes, including those that innervate the SG. In the adult SG the Fmrf gene was highly expressed, but the FMRFamide peptide was in low abundance. Intense staining for FMRFamide in the adult SG was confined to microneurons and fibers in the neuropil and to small fibers surrounding giant axons in stellar nerves. This shows that the Fmrf gene in the SG is strongly regulated post-hatching, and suggests that the FMRFamide precursor is incompletely processed in the adult SG. The data suggest that the SG only employs the Fmrf gene post-hatching and restricts the biosynthesis of FMRFamide, demonstrating that this peptide is not a major transmitter of the giant fiber system. This contrasts with brain lobes that engage FMRFamide embryonically as a regulatory peptide in multiple neuronal systems, including the afferent fibers that innervate the SG. The biological significance of these mechanisms may be to generate diversity within Fmrf-expressing systems in cephalopods.

  9. Effects of dietary squid viscera meal on growth and cadmium accumulation in tissues of large yellow croaker, Pseudosciaena crocea R.

    Institute of Scientific and Technical Information of China (English)

    Huitao LI; Kangsen MAI; Qinghui AI; Chunxiao ZHANG; Lu ZHANG

    2009-01-01

    Cadmium (Cd) is a toxic environmental pollutant with a long biological half-life and can produce both hepatic and renal injuries in mammals and fish. Squid viscera meal (SVM), an effective attractant for aquatic animals, is widely used as an ingredient in aquafeeds. However, SVM is rich in Cd and its complexes. A study was conducted to evaluate the effects of dietary SVM on the growth and Cd deposition in the tissues of large yellow croaker, Pseudosciaena crocea R. Three practical diets diet, correspondingly containing a 0.21, 7.26 and 12.08 mg groups of 100 juveniles of large yellow croaker (mean initial weight, 9.75 + 0.35 g) in floating sea cages (1.0 m × 1.0m × 1.5 m). Fish were fed twice daily (05:00 and 17:00) to satiation for 8 weeks. The results showed that there were no significant differences in fish survival among the three dietary treatments, but significant higher specific growth rates (SGR) were observed in the fish fed diets with (P< 0.05). The cadmium concentrations in fish tissues (muscle, liver, kidney and gill) were significantly influ-enced by the dietary SVM. The cadmium concentrations in all tissues significantly increased with increasing dietary Cd levels (P < 0.05). In all the dietary treatments, the high-est Cd level was always observed in the kidney, followed SVM had significantly higher Cd accumulations in the level in fish muscle, however, was undetectable in all treatments. Therefore, based on these results, accumulation of Cd in edible tissue (muscle) of farmed large yellow croaker is not a food safety issue. However, long-term feeding of diets with SVM may result in accumulation of Cd in the kidney, liver and gills of fish.

  10. Resistively shunted YBa{sub 2}Cu{sub 3}O{sub 7} grain boundary junctions and low-noise SQUIDs patterned by a focused ion beam down to 80 nm linewidth

    Energy Technology Data Exchange (ETDEWEB)

    Nagel, J; Konovalenko, K B; Kemmler, M; Turad, M; Werner, R; Kleiner, R; Koelle, D [Physikalisches Institut-Experimentalphysik II and Center for Collective Quantum Phenomena, Universitaet Tuebingen, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany); Kleisz, E; Menzel, S; Klingeler, R; Buechner, B, E-mail: koelle@uni-tuebingen.de [Leibniz-Institut fuer Festkoerper- und Werkstoffforschung (IFW) Dresden, D-01171 Dresden (Germany)

    2011-01-15

    YBa{sub 2}Cu{sub 3}O{sub 7} 24{sup 0} (30{sup 0}) bicrystal grain boundary junctions (GBJs), shunted with 60 nm (20 nm) thick Au, were fabricated by focused ion beam milling with widths 80 nm {<=} w {<=} 7.8 {mu}m. At 4.2 K we find critical current densities j{sub c} in the 10{sup 5} A cm{sup -2} range (without a clear dependence on w) and an increase in resistance times junction area {rho}{sub n} with an approximate scaling {rho}{sub n{proportional_to}}w{sup 1/2}. For the narrowest GBJs j{sub c{rho}n} = I{sub c}R{sub n{approx}}100 {mu}V (with critical current I{sub c} and junction resistance R{sub n}), which is promising for the realization of sensitive nanoSQUIDs for the detection of small spin systems. We demonstrate that our fabrication process allows the realization of sensitive nanoscale dc SQUIDs; for a SQUID with w{approx}100 nm wide GBJs we find an rms magnetic flux noise spectral density of S{sub {Phi}}{sup 1/2{approx}}4 {mu}{Phi}{sub 0} Hz{sup -1/2} in the white noise limit. We also derive an expression for the spin sensitivity S{sub {mu}}{sup 1/2}, which depends on S{sub {Phi}}{sup 1/2}, on the location and orientation of the magnetic moment of a magnetic particle to be detected by the SQUID, and on the SQUID geometry. For the unoptimized SQUIDs presented here, we estimate S{sub {mu}}{sup 1/2} = 390 {mu}{sub B} Hz{sup -1/2}, which could be further improved by at least an order of magnitude.

  11. 鱿鱼足酶法去皮工艺的优化%Optimization on enzymatic hydrolysis processing of squid tentacles

    Institute of Scientific and Technical Information of China (English)

    王丽丽; 杨宪时; 李学英; 迟海

    2013-01-01

    A study on the processing to remove the skin of squid tentacles (Dosidicus gigas) by enzymatic hydrolysis.The effects were investigated,including enzyme type,reaction temperature,enzyme dosage,time on the L * value and the sensory evaluation value of squid tentacles hydrolyzed.Hydrolysis processing of squid tentacles by animal protein hydrolytic enzyme as the dominant enzyme was explored by response surface methodology on the basis of single factor experiments.The optimal hydrolysis processing conditions were determined as followed:material/liquid ratio 2 ∶ 10(m ∶ V) ; reaction temperature 61 ℃; enzyme dosage 0.25% (measured by material weight); reaction time 45 min.By this process,the experimental value of sensory evaluation was 97.32,and the L* value was 88.67which was ideal result for the enzymatic hydrolysis processing of squid tentacles.%以秘鲁鱿鱼足为原料,选用动物蛋白水解酶、中性蛋白酶、碱性蛋白酶、木瓜蛋白酶酶解去除鱿鱼足表皮,确定优选酶.进而对酶的料液比、酶解温度、时间、酶加量进行考察.参照单因素试验的结果,选取动物蛋白水解酶为优选酶,应用响应面方法,以酶解温度、酶添加量、酶解时间为主要影响因素,酶解后产品的L*值和感官综合评分为双重响应值,对鱿鱼足去皮工艺进行优化.研究确定鱿鱼足酶解去皮最佳工艺参数:添加量0.25%(以物料重计)、料液比确定为2∶10(m∶V)、酶酶解温度61℃、酶解时间45 min,该条件下酶解的鱿鱼足色泽洁白,皮肉完全分离,质地变化小,去皮效果理想.

  12. Fabrication of a compact 1{sup st}-order SQUID gradiometer system to measure fMCG signals in a moderate MSR

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Kwon Kyu; Kim, Ki Woong; Lee, Yong Ho [Korea Reseach Institute of Standards and Science, Daegeon (Korea, Republic of)

    2010-12-15

    We fabricated a low-noise 64-channel axial-type 1{sup st}-order gradiometer system for measuring fetal magnetocardiography (fMCG) signals. A superconducting quantum interference device (SQUID) was based on a double relaxation oscillation SQUID (DROS) with a high flux-to-voltage transfer coefficient to simplify the flux-locked-loop (FLL) circuit. The pickup coil of the SQUID sensor was wound with 125 {mu}m of NbTi wire on a bobbin (20 mm diameter) and had a 1{sup st}-order differential coil to reject the environment noise. The pickup coil was directly connected to a DROS by using a 25 {mu}m superconductive wire and a ultra-wedge bonder. The direct connection between the DROS and the pickup coil improved the balance factor by more than 100 times. The superconductive wire was annealed at 2400 .deg. C in a vacuum chamber to improve the wire's ductility. The 1{sup st}-order gradiometers had a long baseline of 70 mm to detect magnetic signals for the deep source. The structure of between gradiometers is a tri-angle arrangement to minimize the signal loss. Also, the hexagonal structure of the MCG insert was used to cover the maximum area of the subject. The average white noise for all channels of the MCG system was about 3.5 fT/Hz{sup 1/2} at 100 Hz. The fetal MCG was measured for a fetus at 20 {approx} 36 weeks every two weeks in a moderate magnetically shielded room (MSR). The shielding factors of the fabricated MSR with a thin wall thickness of 10 cm were about 35 dB at 0.1Hz and 80 dB at 100Hz. We could measure the complex MCG signals, which were consisted of the maternal MCG, the fetal MCG and environment noise. The signal-to-noise ratio (SNR) of the fMCG was about 10. After averaging 20 times only, we could clearly observe the P, T-peak, as well as QRS complex wave. Thus, we expect the compact SQUID systems to be useful for detecting fetal cardiac diseases.

  13. Survival, growth, and behavior of the Loliginid Squids Loligo plei, Loligo pealei, and Lolliguncula brevis (Mollusca: Cephalopoda) in closed sea water systems

    OpenAIRE

    Roger T. Hanlon; Hixon, Raymond F.; Hulet, William H.

    1983-01-01

    Over 1200 squids were captured by night lighting, trawling, or seining in the northern Gulf of Mexico for laboratory maintenance. Two types of recirculating sea water systems were designed and evaluated: a 2 m circular tank (1500 liter capacity) and a 10 m long raceway (10,000 liters). Mean laboratory survival was: Loligo plei (12 to 252 mm mantle length, ML) 11 days, maximum 84 days; Loligo pealei (109 to 285 mm ML) 28 days, maximum 71 days; Lolliguncula brevis (27 to 99 mm ML) 19 days, maxi...

  14. Functional properties of protein from frozen mantle and fin of jumbo squid Dosidicus gigas in function of pH and ionic strength.

    Science.gov (United States)

    Rocha-Estrada, J G; Córdova-Murueta, J H; García-Carreño, F L

    2010-10-01

    Functional properties of protein from mantle and fin of the jumbo squid Dosidicus gigas were explained based on microscopic muscle fiber and protein fractions profiles as observed in SDS-PAGE. Fin has higher content of connective tissue and complex fiber arrangement, and we observed higher hardness of fin gels as expected. Myosin heavy chain (MHC) was found in sarcoplasmic, myofibril and soluble-in-alkali fractions of mantle and only in sarcoplasmic and soluble-in-alkali fractions of fin. An additive effect of salt concentration and pH affected the solubility and foaming properties. Fin and mantle proteins yielded similar results in solubility tests, but significant differences occurred for specific pH and concentrations of salt. Foaming capacity was proportional to solubility; foam stability was also affected by pH and salt concentration. Hardness and fracture strength of fin gels were significantly higher than mantle gels; gels from proteins of both tissues reached the highest level in the folding test. Structural and molecular properties, such as MHC and paramyosin solubility, arrangement of muscle fibers and the content of connective tissue were useful to explain the differences observed in these protein properties. High-strength gels can be formed from squid mantle or fin muscle. Fin displayed similar or better properties than mantle in all tests.

  15. 鱿鱼皮胶原蛋白提取前处理的条件优化%The ooptimal pretreatment conditions for collagen from squid skin

    Institute of Scientific and Technical Information of China (English)

    王燕; 付万冬; 吴亮亮; 郑斌

    2011-01-01

    To explore the components of squid skin and the optimal pretreatment conditions for extract collagen from squid skin by protease.Select four factors, three levels for each one, by L9 (34) orthogonal experiment ,the optimal conditions were determined.Results show, that the optimal selection for the four factors sodium hydroxide concentration, sodium hydroxide effect time, isopropyl alcohol concentration,activated carbon concentration were 0.15 mol/l,6 h,12%,0.8%, respectively.By this methods the content of collagen was 11.08%, extraction yield of collagen was 93.6%.%试验测定了鱿鱼皮的基本组成成分,探索了酶法提取鱿鱼皮胶原蛋白时前处理的最佳条件.选定了4个因素,3个水平,采用L9(34)正交试验确定了最佳条件.结果表明,4个因素NaOH浓度,NaOH作用时间、异丙醇浓度、活性炭浓度的最佳选择分别为0.15 mol/l、6 h、12%、0.8%,此时提取的胶原蛋白含量为11.08%,提取率为93.6%.

  16. Pygmy squids and giant brains: mapping the complex cephalopod CNS by phalloidin staining of vibratome sections and whole-mount preparations.

    Science.gov (United States)

    Wollesen, T; Loesel, R; Wanninger, A

    2009-04-30

    Among bilaterian invertebrates, cephalopod molluscs (e.g., squids, cuttlefish and octopuses) have a central nervous system (CNS) that rivals in complexity that of the phylogenetically distant vertebrates (e.g., mouse and human). However, this prime example of convergent evolution has rarely been the subject of recent developmental and evolutionary studies, which may partly be due to the lack of suitable neural markers and the large size of cephalopod brains. Here, we demonstrate the usefulness of fluorescence-coupled phalloidin to characterize the CNS of cephalopods using histochemistry combined with confocal laser scanning microscopy. Whole-mount preparations of developmental stages as well as vibratome sections of embryonic and adult brains were analyzed and the benefits of this technique are illustrated. Compared to classical neuroanatomical and antibody-based studies, phalloidin labeling experiments are less time-consuming and allow a high throughput of samples. Besides other advantages summarized here, phalloidin reliably labels the entire neuropil of the CNS of all squids, cuttlefish and octopuses investigated. This facilitates high-resolution in toto reconstructions of the CNS and contributes to a better understanding of the organization of neural networks. Amenable for multi-labeling experiments employing antibodies against neurotransmitters, proteins and enzymes, phalloidin constitutes an excellent neuropil marker for the complex cephalopod CNS.

  17. Effect of diamagnetic contribution of water on harmonics distribution in a dilute solution of iron oxide nanoparticles measured using high-T{sub c} SQUID magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Saari, Mohd Mawardi, E-mail: en19463@s.okayama-u.ac.jp; Tsukamoto, Yuya; Kusaka, Toki; Ishihara, Yuichi; Sakai, Kenji; Kiwa, Toshihiko; Tsukada, Keiji

    2015-11-15

    The magnetization curve of iron oxide nanoparticles in low-concentration solutions was investigated by a highly sensitive high-T{sub c} superconducting quantum interference device (SQUID) magnetometer. The diamagnetic contribution of water that was used as the carrier liquid was observed in the measured magnetization curves in the high magnetic field region over 100 mT. The effect of the diamagnetic contribution of water on the generation of harmonics during the application of AC and DC magnetic fields was simulated on the basis of measured magnetization curves. Although the diamagnetic effect depends on concentration, a linear relation was observed between the detected harmonics and concentration in the simulated and measured results. The simulation results suggested that improvement could be expected in harmonics generation because of the diamagnetic effect when the iron concentration was lower than 72 μg/ml. The use of second harmonics with an appropriate bias of the DC magnetic field could be utilized for realization of a fast and highly sensitive detection of magnetic nanoparticles in a low-concentration solution. - Highlights: • We measured iron oxide nanoparticles solutions using a high-T{sub c} SQUID magnetometer. • Diamagnetic contribution of water in diluted solutions was observed. • Improvement in harmonics generation due to diamagnetism of water could be expected. • Linear relation between harmonics and concentration in diluted solutions was shown. • Detection using second harmonics showed high sensitivity.

  18. Jurassic onychites (hooks from squid-like cephalopods) associated with statolith occurrences in the Wessex Basin, southern England

    Science.gov (United States)

    Hart, Malcolm; Page, Kevin; Price, Gregory; Smart, Christopher; Wilby, Philip

    2016-04-01

    Modern coleoid (squid-like) cephalopods have arms that carry arrays of both suckers and hardened, organic hooks. Fossil arm hooks have been known since the description of Sternberg in 1823, although he identified them as plant remains. During the twentieth century there were a number of brief descriptions of hooks but it was Kulicki & Szaniawski (1972) who described 22 morphotypes from the Jurassic of Poland. These authors gave these 'forms' names using a binomial classification though, with many lacking defined (and figured) holotypes and, in some cases, only one recorded specimen, some of their designations should be regarded as invalid. Some of the morphotypes have, however, been reported from DSDP sites on the Falkland Plateau as well as New Zealand, Germany, Poland and the United Kingdom. It is clear that the hooks must belong to widely distributed members of the Belemnitida and Phragmoteuthida. Exceptional soft-bodied preservation of species such as Belemnotheutis antiquus from the Callovian-Oxfordian of the United Kingdom has allowed the identification of the host animal of some morphotypes, though the majority remain non-attributable. In the Christian Malford lagerstätte (Upper Callovian) of Wiltshire large numbers of hooks (including forms described as Acanthuncus, Arites, Deinuncus, Falcuncus, Longuncus and Paraglycerites) are found associated with an abundance of statoliths (cephalopod 'ear bones') and macrofossil evidence of both belemnites and teuthids, some of which includes exceptional soft-bodied preservation (see Wilby et al., 2004, 2008; Hart et al., in press). Using the abundance of material available to us from the Wessex Basin, we are attempting to identify, where possible, the host animals. If this can be established then it should be possible, using micropalaeontological samples, to determine the stratigraphical and palaeoecological ranges of some of the host macro-fossils, many of which are otherwise rarely preserved. HART, M.B., DE JONGHE

  19. Co-Registration of MEG and ULF MRI using a 7 channel low-Tc SQUID system

    Energy Technology Data Exchange (ETDEWEB)

    Magnelind, Per E [Los Alamos National Laboratory; Sandin, Jan H [Los Alamos National Laboratory; Volegov, Petr L [Los Alamos National Laboratory; Matlashov, Andrei N [Los Alamos National Laboratory; Owens, Tuba [Los Alamos National Laboratory; Gomez, John J [Los Alamos National Laboratory; Espy, Michelle A [Los Alamos National Laboratory

    2010-01-01

    In human brain imaging, e.g. pre-surgical mapping, it is highly desired to obtain images with high spatial and temporal resolution. However, no single imaging device is capable of producing both a high spatial resolution anatomical image and a high temporal resolution functional image. During the last couple of years significant efforts have been directed towards magnetic resonance imaging (MRI) in fields comparable to the Earth's field, i.e. microtesla fields, or lower fields. The fields in this range are called ultra-low fields (ULF). Interestingly, the idea of magnetic resonance at microtesla fields is more than 50 years old. In ULF MR it is essential to use pre-polarization to increase the signal-to-noise ratio of the signal from the precessing spins, since the magnetization from the measurement field alone is very small. Even with the present level of prepolarization the ULF images are not as highly resolved as their high-field counterparts. By using a 7 channel system equipped with low transition temperature (T{sub c}) Superconducting QUantum Interference Devices (SQUIDs) to perform both ULF MRI and magnetoencephalography (MEG), it is possible to coregister a lower resolution ULF MR image and an MEG image obtained during one run. Thereby, the MEG data is aligned to the ULF MR image after performing a calibration run with a phantom. The ULF MR image can then be used to align the MEG data onto a high-field MR image. Recently, our group presented the first brain images obtained by ULF MRI. The MR imaging was combined with an MEG session performed a posteriori. The subject's head was moved in between the MRI run and the MEG run and no reference coils were used to quantify the translation. The main reason for the translation of the head was to improve the coverage of the auditory evoked response. In this paper, we report interleaved ULF MRI and MEG measurements co-registered in the same system.

  20. Electron microscope study on the relationship between macrophages of the alevolar space and spheroid alveolar epithelial cells on mice after injection of squid-ink (sepia-melanin solution into the trachea

    Directory of Open Access Journals (Sweden)

    Suwa,Kiichi

    1977-02-01

    Full Text Available The relationship between alveolar macrophages and spheroid alveolar epithelial cells was studied with the electron microscope after injection of squid-ink solution into the trachea of the mouse. At 20 hours after injection of squid-ink solution slight degeneration was evident in alveolar macrophages with sepia-melanin particles being phagocytized with partial digestion by lysosmes. Furthermore, hardly any changes were seen in mitochondria and inclusion bodies of the spheroid alveolar epithelial cells. In contrast, at one week after injection of squid-ink solution, almost all alveolar macrophages were degenerated with destruction of the ectoplasm in which the ingested sepia-melanin particles were digested by lysosomes into fine particles, and the mitochondria of spheroid alveolar epithelial cells were degenerated and the inclusion bodies were hardly formed. At three weeks after injection of squid-ink solution, alveolar macrophages as well as speroid alveolar epithelial cells showed almost complete recovery of functional structure. As the phagocyte in the alveolar space, neutrophile leucocytes were also observed in addition to the so-called alveolar macrophage.