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Sample records for astaxanthin chiral isomers

  1. Characteristic monomials with chirality fittingness for combinatorial enumeration of isomers with chiral and achiral ligands

    Science.gov (United States)

    Fujita

    2000-09-01

    A new method of combinatorial enumeration based on characteristic monomials with chirality fittingness (CM-CFs) has been proposed in order to enumerate isomers with chiral ligands as well as with achiral ones. The CM-CFs have been defined as monomials that consist of three kinds of dummy variables in light of the subduction of the Q-conjugacy representations for chiral and achiral cyclic groups. A procedure of calculating CM-CFs for cyclic groups and finite groups has been discribed so as to tabulate them as CM-CF tables. Then the CM-CF method has been applied to the enumeration of isomers with achiral ligands as well as chiral ones.

  2. Doped soap membranes selectively permeate a chiral isomer.

    Science.gov (United States)

    Kanyanee, Tinakorn; Jakmunee, Jaroon; Grudpan, Kate; Dasgupta, Purnendu K

    2010-12-29

    Soap films can not only be made with sub-μm thickness, they can have intrinsic permeabilities comparable to many commercial membranes, permitting very high transmembrane flux. Soap films readily incorporate a wide range of modifiers to allow highly tailored selectivity: We show that incorporating α-cyclodextrin in an 890 nm thick Triton-X-100 film allows, in a single stage, a high degree of chirally selective transport (1.6:1) of α(+)-pinene over α(-)-pinene.

  3. Fluorescent Phthalocyanine Assembly Distinguishes Chiral Isomers of Different Types of Amino Acids and Sugars.

    Science.gov (United States)

    Jiang, Yuying; Liu, Chenxi; Wang, Xiqian; Wang, Tianyu; Jiang, Jianzhuang

    2017-07-25

    The functions of some natural supramolecular architectures, such as ribosomes, are dependent on the recognition of different types of chiral biomolecules. However, the recognition of different types of chiral molecules (multiobject chiral recognition), such as amino acids and sugars, by independent and identically artificial supramolecular assembly, was rarely achieved. In this article, simple amphiphilic achiral phthalocyanine was found to form supramolecular chiral assemblies with charged water-soluble polymers upon host-guest interactions at the air/water interface. Among these systems, one identical phthalocyanine/poly(l-lysine) assembly not only can distinguish enantiomers of different amino acids but also can recognize several epimers of monose. The chiral recognitions were achieved by comparing either the steady-state fluorescence intensity or fluorescence quenching rate of phthalocyanine/poly(l-lysine) assemblies, before and after interaction with different small chiral molecules. It was demonstrated that the interactions between poly(l-lysine) and different small chiral molecules could change the aggregation of phthalocyanines. And the sensitivity of fluorescence and the excellent multiobject chiral recognition properties of the phthalocyanine/poly(l-lysine) assembly are dependent on the subtle molecular packing mode and the cooperation of different noncovalent interactions.

  4. Engineered maize as a source of astaxanthin: processing and application as fish feed.

    Science.gov (United States)

    Breitenbach, Jürgen; Nogueira, Marilise; Farré, Gemma; Zhu, Changfu; Capell, Teresa; Christou, Paul; Fleck, Gunther; Focken, Ulfert; Fraser, Paul D; Sandmann, Gerhard

    2016-12-01

    Astaxanthin from a transgenic maize line was evaluated as feed supplement source conferring effective pigmentation of rainbow trout flesh. An extraction procedure using ethanol together with the addition of vegetal oil was established. This resulted in an oily astaxanthin preparation which was not sufficiently concentrated for direct application to the feed. Therefore, a concentration process involving multiple phase partitioning steps was implemented to remove 90 % of the oil. The resulting astaxanthin raw material contained non-esterified astaxanthin with 12 % 4-keto zeaxanthin and 2 % zeaxanthin as additional carotenoids. Isomeric analysis confirmed the exclusive presence of the 3S, 3'S astaxanthin enantiomer. The geometrical isomers were 89 % all-E, 8 % 13-Z and 3 % 9-Z. The incorporation of the oily astaxanthin preparation into trout feed was performed to deliver 7 mg/kg astaxanthin in the final feed formulation for the first 3.5 weeks and 72 mg/kg for the final 3.5 weeks of the feeding trial. The resulting pigmentation of the trout fillets was determined by hue values with a colour meter and further confirmed by astaxanthin quantification. Pigmentation properties of the maize-produced natural astaxanthin incorporated to 3.5 µg/g dw in the trout fillet resembles that of chemically synthesized astaxanthin. By comparing the relative carotenoid compositions in feed, flesh and feces, a preferential uptake of zeaxanthin and 4-keto zeaxanthin over astaxanthin was observed.

  5. [Separation and determination of optical isomers of phenylephrine by chiral ligand exchange capillary elcctrophoresis coupling with the promoting effect of ionic liquid].

    Science.gov (United States)

    Yang, Simei; Zhang, Jiayao; Li, Fei; Hu, Xufang; Cao, Qiue

    2016-01-01

    A method for the separation and determination of optical isomers of phenylephrine was developed based on the promoting effect of non-chiral ionic liquid on chiral ligand-exchange capillary electrophoresis after the electrophoretic parameters were optimized systematically. R-phenylephrine and S-phenylephrine can be separated and determined effectively in 20 mmol/L Tris-H3PO4 buffer solution (pH 5.4) composed of 4.0 mmol/L Cu(II), 8.0 mmol/L L-proline (L-Pro) and 15 mmol/L 1-butyl-3-methylimidazolium chloride ([BMIM] Cl) with the applied voltage of 20 kV, capillary temperature of 25 °C , detection wavelength of 254 nm, and injection of 5 s at 3,447 Pa. The resolution of R- and S-phenylephrines was 1. 42. The linear ranges for the determination of R-phenylephrine and S-phenylephrine were 12. 5 - 150 mg/L and 15. 0-150 mg/L, respectively. The method has been satisfactorily used for the determination of R-phenylephrine and S-phenylephrine in the spiked blood and urine samples. The spiked recoveries in the urine sample were in the range of 93. 7% -108. 2% with the RSDs lower than 3. 18% (n= 3) , and the spiked recoveries in the blood sample were in the range of 91. 4% and 113. 1% with the RSDs lower than 4. 82% (n =3).

  6. Astaxanthin: structural and functional aspects

    OpenAIRE

    Seabra,Larissa Mont'Alverne Jucá; Pedrosa,Lucia Fátima Campos

    2010-01-01

    Astaxanthin, a carotenoid belonging to the xanthophyll class, has stirred great interest due to its antioxidant capacity and its possible role in reducing the risk of some diseases. Astaxanthin occurs naturally in microalgae, such as Haematococcus pluvialis and the yeast Phaffia rhodozyma, and has also been considered to be the major carotenoid in salmon and crustaceans. Shrimp processing waste, which is generally discarded, is also an important source of astaxanthin. The antioxidant activity...

  7. Astaxanthin uptake in domestic dogs and cats

    Directory of Open Access Journals (Sweden)

    Massimino Stefan

    2010-06-01

    Full Text Available Abstract Background Research on the uptake and transport of astaxanthin is lacking in most species. We studied the uptake of astaxanthin by plasma, lipoproteins and leukocytes in domestic dogs and cats. Methods Mature female Beagle dogs (18 to 19 mo old; 11 to 14 kg BW were dosed orally with 0, 0.1, 0.5, 2.5, 10 or 40 mg astaxanthin and blood taken at 0, 3, 6, 9, 12, 18 and 24 h post-administration (n = 8/treatment. Similarly, mature domestic short hair cats (12 mo old; 3 to 3.5 kg body weight were fed a single dose of 0, 0.02, 0.08, 0.4, 2, 5, or 10 mg astaxanthin and blood taken (n = 8/treatment at the same interval. Results Both dogs and cats showed similar biokinetic profiles. Maximal astaxanthin concentration in plasma was approximately 0.14 μmol/L in both species, and was observed at 6 h post-dosing. The plasma astaxanthin elimination half-life was 9 to 18 h. Astaxanthin was still detectable by 24 h in both species. In a subsequent study, dogs and cats were fed similar doses of astaxanthin daily for 15 to 16 d and astaxanthin uptake by plasma, lipoproteins, and leukocytes studied. In both species, plasma astaxanthin concentrations generally continued to increase through d 15 or 16 of supplementation. The astaxanthin was mainly associated with high density lipoprotein (HDL. In blood leukocytes, approximately half of the total astaxanthin was found in the mitochondria, with significant amounts also associated with the microsomes and nuclei. Conclusion Dogs and cats absorb astaxanthin from the diet. In the blood, the astaxanthin is mainly associated with HDL, and is taken up by blood leukocytes, where it is distributed to all subcellular organelles. Certain aspects of the biokinetic uptake of astaxanthin in dogs and cats are similar to that in humans.

  8. A novel radio-tolerant astaxanthin-producing bacterium reveals a new astaxanthin derivative: astaxanthin dirhamnoside.

    Science.gov (United States)

    Asker, Dalal; Awad, Tarek S; Beppu, Teruhiko; Ueda, Kenji

    2012-01-01

    Astaxanthin is a red ketocarotenoid that exhibits extraordinary health-promoting activities such as antioxidant, anti-inflammatory, antitumor, and immune booster. The recent discovery of the beneficial roles of astaxanthin against many degenerative diseases such as cancers, heart diseases, and exercise-induced fatigue has raised its market demand as a nutraceutical and medicinal ingredient in aquaculture, food, and pharmaceutical industries. To satisfy the growing demand for this high-value nutraceuticals ingredient and consumer interest in natural products, many research efforts are being made to discover novel microbial producers with effective biotechnological production of astaxanthin. Using a rapid screening method based on 16S rRNA gene, and effective HPLC-Diodearray-MS methods for carotenoids analysis, we succeeded to isolate a unique astaxanthin-producing bacterium (strain TDMA-17(T)) that belongs to the family Sphingomonadaceae (Asker et al., Appl Microbiol Biotechnol 77: 383-392, 2007). In this chapter, we provide a detailed description of effective HPLC-Diodearray-MS methods for rapid analysis and identification of the carotenoids produced by strain TDMA-17(T). We also describe the methods of isolation and identification for a novel bacterial carotenoid (astaxanthin derivative), a major carotenoid that is produced by strain TDMA-17(T). Finally, we describe the polyphasic taxonomic analysis of strain TDMA-17(T) and the description of a novel species belonging to genus Sphingomonas.

  9. Astaxanthin as a Medical Food

    Directory of Open Access Journals (Sweden)

    Eiji Yamashita

    2013-07-01

    Full Text Available ABSTRACTAstaxanthin is a red pigment that belongs to the carotenoid family like β-carotene. And it’s found in seafood such as crustaceans: shrimp and crabs and fish: salmon and sea bream. Recently, astaxanthin has been reported to have antioxidant activity up to 100 times more potent than that of vitamin E against lipid peroxidation and about 40 times more potent than that of β-carotene on singlet oxygen quenching. Astaxanthin does not show any pro-oxidant activity and its main sight of action is on/in the cell membrane. Various important benefits to date have suggested for human health such as immunomodulation, anti-stress, anti-inflammation, LDL cholesterol oxidation suppression, enhanced skin health, improved semen quality, attenuating eye fatigue, sport performance and endurance, limiting exercised induced muscle damage, suppressing the development of life-style related diseases such as obesity, atherosclerosis, diabetes, hyperlipidemia and hypertension. Nowadays, the research and demand for natural astaxanthin in human health application are explosively growing worldwide. Especially, the clinicians use the astaxanthin extracted from the microalgae, Haematotoccus pluvialis, as an add-on supplementation for the patients who are unsatisfied with the current medications or who can’t receive any medications because of their serious symptom. For example, the treatment enhances their daily activity levels or QOL in heart failure or benign prostatic hypertrophy/lower urinary tract symptom patients. Other studies and trials are under way on chronic diseases such as non-alcoholic steatohepatitis, diabetes and CVD. We may call astaxanthin “a medical food” in the near future.Keywords: astaxanthin, medical food, Haematococcus, add-on supplementation

  10. Astaxanthin diferulate as a bifunctional antioxidant

    DEFF Research Database (Denmark)

    Papa, T.B.R.; Pinho, V.D.; Nascimento, E.P. do

    2015-01-01

    Abstract Astaxanthin when esterified with ferulic acid is better singlet oxygen quencher with k2 = (1.58 ± 0.1) 10(10) L mol(- 1)s(- 1) in ethanol at 25°C compared with astaxanthin with k2 = (1.12 ± 0.01) 10(9) L mol(- 1)s(- 1). The ferulate moiety in the astaxanthin diester is a better radical s....... The mutual enhancement of antioxidant activity for the newly synthetized astaxanthin diferulate becoming a bifunctional antioxidant is rationalized according to a two-dimensional classification plot for electron donation and electron acceptance capability....

  11. Simultaneous extraction of chitin and astaxanthin from waste of ...

    African Journals Online (AJOL)

    From deproteinised exoskeleton, astaxanthin was extracted in methanol, transferred into various vegetable oils, and its concentration measured using spectrophotometry. Maximum stable concentration of astaxanthin in oil was approximately 80 mg ml–1, above which astaxanthin precipitated. Astaxanthin oil prepared from ...

  12. 21 CFR 73.35 - Astaxanthin.

    Science.gov (United States)

    2010-04-01

    ... safe for use in color additive mixtures for coloring foods. (b) Specifications. Astaxanthin shall... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Astaxanthin. 73.35 Section 73.35 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR...

  13. Multispectral Image Analysis for Astaxanthin Coating Classification

    DEFF Research Database (Denmark)

    Ljungqvist, Martin Georg; Ersbøll, Bjarne Kjær; Nielsen, Michael Engelbrecht

    2012-01-01

    Industrial quality inspection using image analysis on astaxanthin coating in aquaculture feed pellets is of great importance for automatic production control. The pellets were divided into two groups: one with pellets coated using synthetic astaxanthin in fish oil and the other with pellets coated...

  14. Pigmenting efficacy of astaxanthin fed to rainbow trout Oncorhynchus mykiss: Effect of dietary astaxanthin and lipid sources

    OpenAIRE

    Choubert, Georges; Mendes-Pinto, Maria Manuela; Morais, Rui

    2006-01-01

    The aim of the present experiment was to investigate the effect of two different dietary types of oil (fish oil (FI) and olive oil (OL)) on the pigmenting efficacy of astaxanthin from the green micro-algae Haematococcus pluvialis (ALG) (total amount of carotenoid pigments 32 mg kg− 1 on a dry weight basis of which astaxanthin accounted for 98.6%) and from the synthetic astaxanthin (AST) in terms of astaxanthin serum concentration, induced muscle colour, and astaxanthin muscle retention in rai...

  15. Characterization and storage stability of astaxanthin esters, fatty acid profile and α-tocopherol of lipid extract from shrimp (L. vannamei) waste with potential applications as food ingredient.

    Science.gov (United States)

    Gómez-Estaca, J; Calvo, M M; Álvarez-Acero, I; Montero, P; Gómez-Guillén, M C

    2017-02-01

    In this work a lipid extract from shrimp waste was obtained and characterized. The most abundant fatty acids found were C16:0, C18:2n6c, C18:1n9c, C22:6n3, and C20:5n3. The extract contained all-trans-astaxanthin, two cis-astaxanthin isomers, 5 astaxanthin monoesters, and 10 astaxanthin diesters (7±1mg astaxanthin/g). C22:6n3 and C20:5n3 were the most frequent fatty acids in the esterified forms. Appreciable amounts of α-tocopherol and cholesterol were also found (126±11mg/g and 65±1mg/g, respectively). Little lipid oxidation was observed after 120days of storage at room temperature, revealed by a slight reduction of ω-3 fatty acids, but neither accumulation of TBARS nor formation of oxidized cholesterol forms was found. This is attributed to the antioxidant effect of astaxanthin and α-tocopherol, as their concentrations decreased as storage continued. The lipid extract obtained has interesting applications as food ingredient, owing to the coloring capacity and the presence of healthy components. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Evaluation of hepatoprotective and antioxidant activity of astaxanthin and astaxanthin esters from microalga-Haematococcus pluvialis

    OpenAIRE

    Rao, A Ranga; Sarada, R.; Shylaja, M. D.; Ravishankar, G.A.

    2015-01-01

    Effect of isolated astaxanthin (ASX) and astaxanthin esters (ASXEs) from green microalga-Haematococcus pluvialis on hepatotoxicity and antioxidant activity against carbon tetrachloride (CCl4) induced toxicity in rats was compared with synthetic astaxanthin (SASX). ASX, ASXEs, and SASX, all dissolved in olive oil, fed to rats with 100 and 250 μg/kg b.w for 14 days. They were evaluated for their hepatoprotective and antioxidant activity by measuring appropriate enzymes. Among the treated groups...

  17. Engineering of Yarrowia lipolytica for production of astaxanthin

    Directory of Open Access Journals (Sweden)

    Kanchana Rueksomtawin Kildegaard

    2017-12-01

    Our study for the first time reports engineering of Y. lipolytica for the production of astaxanthin. The high astaxanthin content and titer obtained even in a small-scale cultivation demonstrates a strong potential for Y. lipolytica-based fermentation process for astaxanthin production.

  18. Colloidal astaxanthin: preparation, characterisation and bioavailability evaluation.

    Science.gov (United States)

    Anarjan, Navideh; Tan, Chin Ping; Nehdi, Imededdine Arbi; Ling, Tau Chuan

    2012-12-01

    Astaxanthin colloidal particles were produced using solvent-diffusion technique in the presence of different food grade surface active compounds, namely, Polysorbate 20 (PS20), sodium caseinate (SC), gum Arabic (GA) and the optimum combination of them (OPT). Particle size and surface charge characteristics, rheological behaviour, chemical stability, colour, in vitro cellular uptake, in vitro antioxidant activity and residual solvent concentration of prepared colloidal particles were evaluated. The results indicated that in most cases the mixture of surface active compounds lead to production of colloidal particles with more desirable physicochemical and biological properties, as compared to using them individually. The optimum combination of PS20, SC and GA could produce the astaxanthin colloidal particles with small particle size, polydispersity index (PDI), conductivity and higher zeta potential, mobility, cellular uptake, colour intensity and in vitro antioxidant activity. In addition, all prepared astaxanthin colloidal particles had significantly (ppowder. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Lipase-Catalyzed Kinetic Resolution of Aryltrimethylsilyl Chiral Alcohols

    Directory of Open Access Journals (Sweden)

    Leandro H. Andrade

    2011-11-01

    Full Text Available Lipase-catalyzed kinetic resolution of aryltrimethylsilyl chiral alcohols through a transesterification reaction was studied. The optimal conditions found for the kinetic resolution of m- and p-aryltrimethylsilyl chiral alcohols, led to excellent results, high conversions (c = 50%, high enantiomeric ratios (E > 200 and enantiomeric excesses for the remaining (S-alcohol and (R-acetylated product (>99%. However, kinetic resolution of o-aryltrimethylsilyl chiral alcohols did not occur under the same conditions applied to the other isomers.

  20. Reagent controlled addition of chiral sulfur ylides to chiral aldehydes

    Directory of Open Access Journals (Sweden)

    Bi Jie

    2005-08-01

    Full Text Available Abstract The degree of reagent and substrate control in the reaction of chiral sulfur ylides with chiral aldehydes has been investigated. Specifically, the reactions of the two enantiomers of the chiral benzyl sulfonium salt 1 with glyceraldehyde acetonide were studied in detail. Of the two new stereogenic centers created, it was found that the C1 stereochemistry was largely controlled by the reagent, whereas control at the C2 center was dependent on the aldehyde used. In one case, the trans isomer was produced via reversible formation of the intermediate betaine, whereas in the alternative case, the C2 center was under Felkin Anh/Cornforth control through non-reversible formation of the betaine. Thus, the aldehyde stereocenter influenced the degree of reversibility in betaine formation, which impacted on the stereocontrol at the C2 position.

  1. Free Radical Scavenging and Cellular Antioxidant Properties of Astaxanthin

    Directory of Open Access Journals (Sweden)

    Janina Dose

    2016-01-01

    Full Text Available Astaxanthin is a coloring agent which is used as a feed additive in aquaculture nutrition. Recently, potential health benefits of astaxanthin have been discussed which may be partly related to its free radical scavenging and antioxidant properties. Our electron spin resonance (ESR and spin trapping data suggest that synthetic astaxanthin is a potent free radical scavenger in terms of diphenylpicryl-hydrazyl (DPPH and galvinoxyl free radicals. Furthermore, astaxanthin dose-dependently quenched singlet oxygen as determined by photon counting. In addition to free radical scavenging and singlet oxygen quenching properties, astaxanthin induced the antioxidant enzyme paroxoanase-1, enhanced glutathione concentrations and prevented lipid peroxidation in cultured hepatocytes. Present results suggest that, beyond its coloring properties, synthetic astaxanthin exhibits free radical scavenging, singlet oxygen quenching, and antioxidant activities which could probably positively affect animal and human health.

  2. Benzene and its Isomers

    Indian Academy of Sciences (India)

    Compared to our present vast knowledge of extremely complex structures of thousands of organic compounds, the struc- .... None of the isomers, except benzene, has much practical applica- tion. Yet the fascination of both synthetic and theoretical chemists for the isomers of benzene is so great that even after about 140 ...

  3. Chiral photochemistry

    CERN Document Server

    Inoue, Yoshihisa

    2004-01-01

    Direct Asymmetric Photochemistry with Circularly Polarized Light, H. RauCoherent Laser Control of the Handedness of Chiral Molecules, P. Brumer and M. ShapiroMagnetochiral Anisotropy in Asymmetric Photochemistry, G.L.J.A.RikkenEnantiodifferentiating Photosensitized Reactions, Y. InoueDiastereodifferentiating Photoreactions, N. Hoffmann and J.-P. PeteChirality in Photochromism, Y. Yokoyama and M. SaitoChiral Photochemistry with Transition Metal Complexes, S. Sakaki and T. HamadaTemplate-Induced Enantioselective Photochemical Reactions in S

  4. Chiral algebras

    CERN Document Server

    Beilinson, Alexander

    2004-01-01

    Chiral algebras form the primary algebraic structure of modern conformal field theory. Each chiral algebra lives on an algebraic curve, and in the special case where this curve is the affine line, chiral algebras invariant under translations are the same as well-known and widely used vertex algebras. The exposition of this book covers the following topics: the "classical" counterpart of the theory, which is an algebraic theory of non-linear differential equations and their symmetries; the local aspects of the theory of chiral algebras, including the study of some basic examples, such as the ch

  5. Chirality of methamphetamine and amphetamine from workplace urine samples.

    Science.gov (United States)

    Cooke, B J

    1994-01-01

    Several positive methamphetamine/amphetamine urine samples were reexamined to determine the chirality of the detected drug or drugs. (S)-N-(Trifluoroacetyl)prolyl derivatives were prepared and analyzed using GC/MS. In one case, pure d-isomers of methamphetamine and amphetamine were detected. In the remainder of the samples involving both drugs, skewed racemates were detected, with the l-isomer of methamphetamine and the d-isomer of amphetamine predominating slightly over their enantiomers. In samples involving amphetamine only, 50:50 mixtures of d- and l-isomers were detected. In no instance was pure i-methamphetamine (from a Vicks inhaler) detected.

  6. Assignment of the stereochemistry of the isomers of IQNP

    Energy Technology Data Exchange (ETDEWEB)

    McPherson, D.W.; Knapp, F.F. Jr. [Oak Ridge National Lab., TN (United States)

    1996-05-01

    The isomers of 1-azabicyclo[2.2.2]oct-3-yl {alpha}-hydroxy-{alpha}-(1-iodo-1-propen-3-yl)-{alpha}-phenylacetate (IQNP) are attractive for in vivo imaging of muscarinic receptors (mAChR). Although the stereocenter of the quinuclidinyl ring has been studied, the isomers of IQNP are oils and the configuration of the acetate center has not been elucidated. An improved synthesis of the acetate moiety (3) via a chiral intermediate has been developed and allows assignment of the configuration of the acetate. 1,3-dioxolan-4-one (1), (condensation of R- or S-mandelic acid and pivaldehyde) was alkylated with propargyl bromide, treated with base and esterified to afford R-(-)- or S-(+)-3. R- and S-3 were prepared in a 94:6 and 98:2 enantiomeric excess, respectively (HPLC analysis). R- and S-3 were utilized to synthesize the various isomers of IQNP. By comparing the optical rotation, HPLC and NMR of these isomers to those prepared by classical resolution allows the assignment of E-R, R-IQNP as the isomer demonstrating binding to M{sub 1} mAChR subtype and Z-R, R-IQNP as the isomer binding to M{sub 1} and M{sub 2}mAChR subtypes. This route also permits a simplified route for the preparation of the isomers of IQNP.

  7. Astaxanthin: a review of its chemistry and applications.

    Science.gov (United States)

    Higuera-Ciapara, I; Félix-Valenzuela, L; Goycoolea, F M

    2006-01-01

    Astaxanthin is a carotenoid widely used in salmonid and crustacean aquaculture to provide the pink color characteristic of that species. This application has been well documented for over two decades and is currently the major market driver for the pigment. Additionally, astaxanthin also plays a key role as an intermediary in reproductive processes. Synthetic astaxanthin dominates the world market but recent interest in natural sources of the pigment has increased substantially. Common sources of natural astaxanthin are the green algae Haematococcus pluvialis, the red yeast, Phaffia rhodozyma, as well as crustacean byproducts. Astaxanthin possesses an unusual antioxidant activity which has caused a surge in the nutraceutical market for the encapsulated product. Also, health benefits such as cardiovascular disease prevention, immune system boosting, bioactivity against Helycobacter pylori, and cataract prevention, have been associated with astaxanthin consumption. Research on the health benefits of astaxanthin is very recent and has mostly been performed in vitro or at the pre-clinical level with humans. This paper reviews the current available evidence regarding astaxanthin chemistry and its potential beneficial effects in humans.

  8. Multispectral Image Analysis for Robust Prediction of Astaxanthin Coating

    DEFF Research Database (Denmark)

    Ljungqvist, Martin Georg; Frosch, Stina; Nielsen, Michael Engelbrecht

    2013-01-01

    The aim of this study was to investigate the possibility of predicting the type and concentration level of astaxanthin coating of aquaculture feed pellets using multispectral image analysis. We used both natural and synthetic astaxanthin, and we used several different concentration levels...... regression (PLSR) for prediction of the concentration level. The results show that it is possible to predict the level of synthetic astaxanthin coating using PLSR on either the same recipe, or when calibrating on all recipes. The concentration prediction is adequate for screening for all recipes. Moreover......, it shows that it is possible to predict the type of astaxanthin used in the coating using only ten spectral bands. Finally, the most selected spectral bands for astaxanthin prediction are in the visible range of the spectrum....

  9. Anomalous circular dichroism in high harmonic generation of stereoisomers with two chiral centers.

    Science.gov (United States)

    Zhu, Xiaosong; Liu, Xi; Lan, Pengfei; Wang, Dian; Zhang, Qingbin; Li, Wei; Lu, Peixiang

    2016-10-31

    When a molecule has more than one chiral center, it can be either a chiral molecule or a meso isomer. High harmonic generation (HHG) of stereoisomers with two chiral centers driven by circularly polarized (CP) laser pulses is investigated. Counterintuitively, it is found that the HHG exhibits prominent circular dichroism for the meso isomer, while the harmonic spectra with left and right CP laser pulses are nearly the same for the chiral isomers. We show that the anomalous circular dichroism is attributed to the characteristic recollision dynamics of HHG. This feature makes the HHG a promising tool to discriminate the meso isomer and racemic mixture, where no optical activity can be found in both cases. Similar dichroism responses are also found by applying the counter-rotating bicircular laser pulses.

  10. Chiral plasmonics

    Science.gov (United States)

    Hentschel, Mario; Schäferling, Martin; Duan, Xiaoyang; Giessen, Harald; Liu, Na

    2017-01-01

    We present a comprehensive overview of chirality and its optical manifestation in plasmonic nanosystems and nanostructures. We discuss top-down fabricated structures that range from solid metallic nanostructures to groupings of metallic nanoparticles arranged in three dimensions. We also present the large variety of bottom-up synthesized structures. Using DNA, peptides, or other scaffolds, complex nanoparticle arrangements of up to hundreds of individual nanoparticles have been realized. Beyond this static picture, we also give an overview of recent demonstrations of active chiral plasmonic systems, where the chiral optical response can be controlled by an external stimulus. We discuss the prospect of using the unique properties of complex chiral plasmonic systems for enantiomeric sensing schemes. PMID:28560336

  11. Atlas of Nuclear Isomers

    Science.gov (United States)

    Jain, Ashok Kumar; Maheshwari, Bhoomika; Garg, Swati; Patial, Monika; Singh, Balraj

    2015-09-01

    We present an atlas of nuclear isomers containing the experimental data for the isomers with a half-life ≥ 10 ns together with their various properties such as excitation-energy, half-life, decay mode(s), spin-parity, energies and multipolarities of emitted gamma transitions, etc. The ENSDF database complemented by the XUNDL database has been extensively used in extracting the relevant data. Recent literature from primary nuclear physics journals, and the NSR bibliographic database have been searched to ensure that the compiled data Table is as complete and current as possible. The data from NUBASE-12 have also been checked for completeness, but as far as possible original references have been cited. Many interesting systematic features of nuclear isomers emerge, some of them new; these are discussed and presented in various graphs and figures. The cutoff date for the extraction of data from the literature is August 15, 2015.

  12. Atlas of Nuclear Isomers

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Ashok Kumar, E-mail: ajainfph@iitr.ac.in [Department of Physics, Indian Institute of Technology, Roorkee-247667 (India); Maheshwari, Bhoomika; Garg, Swati; Patial, Monika [Department of Physics, Indian Institute of Technology, Roorkee-247667 (India); Singh, Balraj [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario-L8S 4M1 (Canada)

    2015-09-15

    We present an atlas of nuclear isomers containing the experimental data for the isomers with a half-life ≥ 10 ns together with their various properties such as excitation-energy, half-life, decay mode(s), spin-parity, energies and multipolarities of emitted gamma transitions, etc. The ENSDF database complemented by the XUNDL database has been extensively used in extracting the relevant data. Recent literature from primary nuclear physics journals, and the NSR bibliographic database have been searched to ensure that the compiled data Table is as complete and current as possible. The data from NUBASE-12 have also been checked for completeness, but as far as possible original references have been cited. Many interesting systematic features of nuclear isomers emerge, some of them new; these are discussed and presented in various graphs and figures. The cutoff date for the extraction of data from the literature is August 15, 2015.

  13. Li(+)-induced selective gelation of discrete homochiral structural isomers derived from L-tartaric acid.

    Science.gov (United States)

    Dubey, Mrigendra; Kumar, Ashish; Gupta, Rakesh Kumar; Pandey, Daya Shankar

    2014-08-04

    Two chiral structural isomers have been synthesized by molecular engineering of L-tartaric acid. In the presence of LiOH isomer forms a thermally stable, fluorescent gel which exhibits interesting nano-cluster morphology, anomalous optical and rheological properties whilst forms a non-fluorescent solution under similar conditions. The current-voltage (I-V) curve followed a non-linear trend, rationally in close proximity to the diode characteristic curve.

  14. Biocompatible astaxanthin as novel contrast agent for biomedical imaging.

    Science.gov (United States)

    Nguyen, Van Phuc; Park, Suhyun; Oh, Junghwan; Wook Kang, Hyun

    2017-08-01

    Photoacoustic imaging (PAI) is a hybrid imaging modality with high resolution and sensitivity that can be beneficial for cancer staging. Due to insufficient endogenous photoacoustic (PA) contrast, the development of exogenous agents is critical in targeting cancerous tumors. The current study demonstrates the feasibility of marine-oriented material, astaxanthin, as a biocompatible PA contrast agent. Both silicon tubing phantoms and ex vivo bladder tissues are tested at various concentrations (up to 5 mg/ml) of astaxanthin to quantitatively explore variations in PA responses. A Q-switched Nd : YAG laser (λ = 532 nm) in conjunction with a 5 MHz ultrasound transducer is employed to generate and acquire PA signals from the samples. The phantom results presented that the PA signal amplitudes increase linearly with the astaxanthin concentrations (threshold detection = 0.31 mg/ml). The tissue injected with astaxanthin yields up to 16-fold higher PA signals, compared with that with saline. Due to distribution of the injected astaxanthin, PAI can image the margin of astaxanthin boles as well as quantify their volume in 3D reconstruction. Further investigations on selective tumor targeting are required to validate astaxanthin as a potential biocompatible contrast agent for PAI-assisted bladder cancer detection. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Chiral liquid chromatography-circular dichroism-NMR for estimating separation conditions of chiral HPLC without authentic samples.

    Science.gov (United States)

    Tokunaga, Takashi; Okamoto, Masahiko; Tanaka, Kozo; Tode, Chisato; Sugiura, Makiko

    2010-05-15

    Chiral separation by high performance liquid chromatography (Chiral HPLC) is one of the most powerful methods for estimating optical and chemical purity of chiral compounds. However, it has a weakness in that much time and effort are required to prepare authentic samples. A novel chiral liquid chromatography-circular dichroism-NMR (LC-CD-NMR) technique, on the other hand, requires only crude chiral compounds that include enantiomers as minor impurities. In this study, chiral LC-CD-NMR was constructed by connecting a conventional LC-NMR system with a CD detector. A pyridylalanine derivative mixture was prepared to mimic technical grade material in an early phase of development. By chiral LC-CD-NMR, the enantiomer peak is identified by an opposite sign of the CD Cotton effect curve and an identical (1)H NMR spectrum to that of the main component. Using NMR as a detector, this method is superior in ability to discriminate enantiomers from other isomers indistinguishable by MS. Furthermore, this method is also applicable for selecting the best separation conditions of chiral HPLC. The degrees of separation (Rs) between the main component and its enantiomer in several chiral columns were compared. Even with modern chromatographic methods, establishing the best chiral HPLC conditions in an early phase of development is difficult: chiral LC-CD-NMR is a suitable solution.

  16. Astaxanthin as a Potential Neuroprotective Agent for Neurological Diseases

    Directory of Open Access Journals (Sweden)

    Haijian Wu

    2015-09-01

    Full Text Available Neurological diseases, which consist of acute injuries and chronic neurodegeneration, are the leading causes of human death and disability. However, the pathophysiology of these diseases have not been fully elucidated, and effective treatments are still lacking. Astaxanthin, a member of the xanthophyll group, is a red-orange carotenoid with unique cell membrane actions and diverse biological activities. More importantly, there is evidence demonstrating that astaxanthin confers neuroprotective effects in experimental models of acute injuries, chronic neurodegenerative disorders, and neurological diseases. The beneficial effects of astaxanthin are linked to its oxidative, anti-inflammatory, and anti-apoptotic characteristics. In this review, we will focus on the neuroprotective properties of astaxanthin and explore the underlying mechanisms in the setting of neurological diseases.

  17. Multispectral Imaging for Determination of Astaxanthin Concentration in Salmonids

    DEFF Research Database (Denmark)

    Dissing, Bjørn Skovlund; Nielsen, Michael Engelbrecht; Ersbøll, Bjarne Kjær

    2011-01-01

    Multispectral imaging has been evaluated for characterization of the concentration of a specific cartenoid pigment; astaxanthin. 59 fillets of rainbow trout, Oncorhynchus mykiss, were filleted and imaged using a rapid multispectral imaging device for quantitative analysis. The multispectral imagi...

  18. Multispectral imaging for determination of astaxanthin concentration in salmonids.

    Directory of Open Access Journals (Sweden)

    Bjørn S Dissing

    Full Text Available Multispectral imaging has been evaluated for characterization of the concentration of a specific cartenoid pigment; astaxanthin. 59 fillets of rainbow trout, Oncorhynchus mykiss, were filleted and imaged using a rapid multispectral imaging device for quantitative analysis. The multispectral imaging device captures reflection properties in 19 distinct wavelength bands, prior to determination of the true concentration of astaxanthin. The samples ranged from 0.20 to 4.34 g per g fish. A PLSR model was calibrated to predict astaxanthin concentration from novel images, and showed good results with a RMSEP of 0.27. For comparison a similar model were built for normal color images, which yielded a RMSEP of 0.45. The acquisition speed of the multispectral imaging system and the accuracy of the PLSR model obtained suggest this method as a promising technique for rapid in-line estimation of astaxanthin concentration in rainbow trout fillets.

  19. Towards noninvasive drug distribution in tissues: coherent Raman microspectroscopy of chiral molecules

    Science.gov (United States)

    Petrov, Georgi I.; Yakovlev, Vladislav V.

    2017-02-01

    Many biologically active molecules are chiral. Many drugs, which are currently in use, are supplied as an equimolar mixture of enantiomers. Although they have the same chemical structure, i.e. are not distinguishable by conventional Raman spectroscopy, most isomers of chiral drugs exhibit marked differences in biological activities such as pharmacology, toxicology, pharmacokinetics, metabolism, etc. In this report we introduced a new spectroscopic tool to extend nonlinear Raman spectroscopy to chiral substances.

  20. Evaluation of hepatoprotective and antioxidant activity of astaxanthin and astaxanthin esters from microalga-Haematococcus pluvialis.

    Science.gov (United States)

    Rao, A Ranga; Sarada, R; Shylaja, M D; Ravishankar, G A

    2015-10-01

    Effect of isolated astaxanthin (ASX) and astaxanthin esters (ASXEs) from green microalga-Haematococcus pluvialis on hepatotoxicity and antioxidant activity against carbon tetrachloride (CCl4) induced toxicity in rats was compared with synthetic astaxanthin (SASX). ASX, ASXEs, and SASX, all dissolved in olive oil, fed to rats with 100 and 250 μg/kg b.w for 14 days. They were evaluated for their hepatoprotective and antioxidant activity by measuring appropriate enzymes. Among the treated groups, the SGPT, SGOT and ALP levels were decreased by 2, 2.4, and 1.5 fold in ASXEs treated group at 250 μg/Kg b.w. when compared to toxin group. Further, antioxidant enzymes catalase, glutathione, superoxide dismutase and lipid peroxidase levels were estimated in treated groups, their levels were reduced by 30-50 % in the toxin group, however these levels restored by 136.95 and 238.48 % in ASXEs treated group at 250 μg/kg. The lipid peroxidation was restored by 5.2 and 2.8 fold in ASXEs and ASX treated groups at 250 μg/kg. The total protein, albumin and bilirubin contents were decreased in toxin group, whereas normalized in ASXEs treated group. These results indicates that ASX and ASXEs have better hepatoprotection and antioxidant activity, therefore can be used in pharmaceutical and nutraceutical applications and also extended to use as food colorant.

  1. Chiral pinwheel clusters lacking local point chirality.

    Science.gov (United States)

    Sun, Kai; Shao, Ting-Na; Xie, Jia-Le; Lan, Meng; Yuan, Hong-Kuan; Xiong, Zu-Hong; Wang, Jun-Zhong; Liu, Ying; Xue, Qi-Kun

    2012-07-09

    The supramolecular pinwheel cluster is a unique chiral structure with evident handedness. Previous studies reveal that the chiral pinwheels are composed of chiral or achiral molecules with polar groups, which result in strong intermolecular interactions such as hydrogen-bonding or dipole interactions. Herein, it is shown that the simple linear aromatic molecule, pentacene, can be self-assembled into large chiral pinwheel clusters on the semimetal Bi(111) surface, due to enhanced intermolecular interactions. The pentacene pinwheels reveal two levels of organizational chirality: the chiral hexamers resulting from asymmetric shifting along the long molecular axis, and chiral arrangement of six hexamers with a rotor motif. Furthermore, a new relation between the local point chirality and organizational chirality is identified from the pinwheels: the former is not essential for the latter in 2D pinwheel clusters of the pentacene molecule. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Punctuated Chirality

    OpenAIRE

    Gleiser, Marcelo; Thorarinson, Joel; Walker, Sara Imari

    2008-01-01

    Most biomolecules occur in mirror, or chiral, images of each other. However, life is homochiral: proteins contain almost exclusively levorotatory (L) amino acids, while only dextrorotatory (R) sugars appear in RNA and DNA. The mechanism behind this fundamental asymmetry of life remains an open problem. Coupling the spatiotemporal evolution of a general autocatalytic polymerization reaction network to external environmental effects, we show through a detailed statistical analysis that high int...

  3. Chiral streamers

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Dandan; Cao, Xin [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Lu, Xinpei, E-mail: luxinpei@hotmail.com [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Ostrikov, Kostya [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland 4000 (Australia); Comonwealth Scientific and Industrial Research Organization, P.O. Box 218, Sydney, New South Wales 2070 (Australia)

    2015-10-15

    The interaction of time-varying electromagnetic fields and solid, liquid, and gaseous matter may lead to electrical breakdown phenomena through the excitation of ionization waves or streamers that control the dynamics of localized plasma propagation through the media. The streamers usually propagate along straight lines, either between random points in space or along a certain direction in a guided mode. Here, we report on a new type of plasma discharges with the regular helical propagation pattern driven by a pulsed dc voltage in nitrogen at sub-atmospheric-pressure conditions. The helical guided streamers, named chiral streamers or chi-streamers, are excited without any external magnetic fields, which commonly cause helical plasma motions. We also demonstrate a hybrid propagation mode involving the interchangeable chiral streamers and the straight-line propagating plasmas. High-speed, time-resolved optical imaging reveals that the chiral streamers and the hybrid patterns are made of spatially localized discrete plasma bullets, similar to the straight-line guided streamers. These results may enable effective control of propagation of confined plasmas and electromagnetic energy along pre-determined, potentially deterministic paths, which have important implications for the development of next-generation plasma-based radiation sources, communication devices, and medical treatments.

  4. Chiral Nanotubes

    Directory of Open Access Journals (Sweden)

    Andrea Nitti

    2017-07-01

    Full Text Available Organic nanotubes, as assembled nanospaces, in which to carry out host–guest chemistry, reversible binding of smaller species for transport, sensing, storage or chemical transformation purposes, are currently attracting substantial interest, both as biological ion channel mimics, or for addressing tailored material properties. Nature’s materials and machinery are universally asymmetric, and, for chemical entities, controlled asymmetry comes from chirality. Together with carbon nanotubes, conformationally stable molecular building blocks and macrocycles have been used for the realization of organic nanotubes, by means of their assembly in the third dimension. In both cases, chiral properties have started to be fully exploited to date. In this paper, we review recent exciting developments in the synthesis and assembly of chiral nanotubes, and of their functional properties. This review will include examples of either molecule-based or macrocycle-based systems, and will try and rationalize the supramolecular interactions at play for the three-dimensional (3D assembly of the nanoscale architectures.

  5. Strain improvement of Phaffia rhodozyma for astaxanthin production

    Directory of Open Access Journals (Sweden)

    Hina Nangia

    2016-01-01

    Full Text Available Objective: The aim of the present study is to evaluate and optimize different carbon sources at different temperatures in shake flask for cell growth and astaxanthin accumulation in ultraviolet (UV mutant Phaffia rhodozyma. The focus is to make the process cost-effective and fruitful with higher productivity. Materials and Methods: Adaptive strain development was carried out so that the P. rhodozyma can give the best astaxanthin at a higher temperature (35°C, increasing the process economy. P. rhodozyma was cultivated with three broad spectrum antibacterial drugs - streptomycin, gentamycin, and ampicillin (200 μL and with antifungal drug - fluconazole (200 μL to determine the effect on yeast growth and astaxanthin production. Rice, cane juice, and sucrose were selected as carbon source and compared with dextrose at different fermentation temperatures - 22°C, 30°C, 33°C, and 35°C for astaxanthin production. Results: P. rhodozyma was resistant to antibiotic drugs inhibiting bacterial and fungal contaminants. Rice being more economical was selected as carbon source, but the strain was not able to utilize starch-rich substrate leading to its rejection. When P. rhodozyma was grown in cane juice, biomass is highest (OD 2.77 at 30°C and 610 nm wavelength, whereas astaxanthin productivity is highest (OD 2.64 in dextrose media at 30°C and 450 nm. Comparative metabolic and growth results for UV mutants showed significantly higher biomass and astaxanthin productivity in comparison to wild strain. Conclusion: The most efficient carbon source in terms of penny-pinching and astaxanthin productivity was found to be dextrose containing media at 30°C.

  6. Biosynthesis of astaxanthin in tobacco leaves by transplastomic engineering.

    Science.gov (United States)

    Hasunuma, Tomohisa; Miyazawa, Shin-Ichi; Yoshimura, Satomi; Shinzaki, Yuki; Tomizawa, Ken-Ichi; Shindo, Kazutoshi; Choi, Seon-Kang; Misawa, Norihiko; Miyake, Chikahiro

    2008-09-01

    The natural pigment astaxanthin has attracted much attention because of its beneficial effects on human health, despite its expensive market price. In order to produce astaxanthin, transgenic plants have so far been generated through conventional genetic engineering of Agrobacterium-mediated gene transfer. The results of trials have revealed that the method is far from practicable because of low yields, i.e. instead of astaxanthin, large quantities of the astaxanthin intermediates, including ketocarotenoids, accumulated in the transgenic plants. In the present study, we have overcome this problem, and have succeeded in producing more than 0.5% (dry weight) astaxanthin (more than 70% of total caroteniods) in tobacco leaves, which turns their green color to reddish brown, by expressing both genes encoding CrtW (beta-carotene ketolase) and CrtZ (beta-carotene hydroxylase) from a marine bacterium Brevundimonas sp., strain SD212, in the chloroplasts. Moreover, the total carotenoid content in the transplastomic tobacco plants was 2.1-fold higher than that of wild-type tobacco. The tobacco transformants also synthesized a novel carotenoid 4-ketoantheraxanthin. There was no significant difference in the size of the aerial part of the plant between the transformants and wild-type plants at the final stage of their growth. The photosynthesis rate of the transformants was also found to be similar to that of wild-type plants under ambient CO2 concentrations of 1500 micromol photons m(-2) s(-1) light intensity.

  7. Preparation of Astaxanthin Nanodispersions Using Gelatin-Based Stabilizer Systems

    Directory of Open Access Journals (Sweden)

    Navideh Anarjan

    2014-09-01

    Full Text Available The incorporation of lipophilic nutrients, such as astaxanthin (a fat soluble carotenoid in nanodispersion systems can either increase the water solubility, stability and bioavailability or widen their applications in aqueous food and pharmaceutical formulations. In this research, gelatin and its combinations with sucrose oleate as a small molecular emulsifier, sodium caseinate (SC as a protein and gum Arabic as a polysaccharide were used as stabilizer systems in the formation of astaxanthin nanodispersions via an emulsification-evaporation process. The results indicated that the addition of SC to gelatin in the stabilizer system could increase the chemical stability of astaxanthin nanodispersions significantly, while using a mixture of gelatin and sucrose oleate as a stabilizer led to production of nanodispersions with the smallest particle size (121.4 ± 8.6 nm. It was also shown that a combination of gelatin and gum Arabic could produce optimal astaxanthin nanodispersions in terms of physical stability (minimum polydispersity index (PDI and maximum zeta-potential. This study demonstrated that the mixture of surface active compounds showed higher emulsifying and stabilizing functionality compared to using them individually in the preparation of astaxanthin nanodispersions.

  8. Improving the Stability of Astaxanthin by Microencapsulation in Calcium Alginate Beads.

    Directory of Open Access Journals (Sweden)

    Shen-Fu Lin

    Full Text Available There has been considerable interest in the biological functions of astaxanthin and its potential applications in the nutraceutical, cosmetics, food, and feed industries in recent years. However, the unstable structure of astaxanthin considerably limits its application. Therefore, this study reports the encapsulation of astaxanthin in calcium alginate beads using the extrusion method to improve its stability. This study also evaluates the stability of the encapsulated astaxanthin under different storage conditions. The evaluation of astaxanthin stability under various environmental factors reveals that temperature is the most influential environmental factor in astaxanthin degradation. Stability analysis shows that, regardless of the formulation used, the content of astaxanthin encapsulated in alginate beads remains above 90% of the original amount after 21 days of storage at 25°C. These results suggest that the proposed technique is a promising way to enhance the stability of other sensitive compounds.

  9. Effect of Astaxanthin on Human Sperm Capacitation

    Directory of Open Access Journals (Sweden)

    Luciana Bordin

    2013-06-01

    Full Text Available In order to be able to fertilize oocytes, human sperm must undergo a series of morphological and structural alterations, known as capacitation. It has been shown that the production of endogenous sperm reactive oxygen species (ROS plays a key role in causing cells to undergo a massive acrosome reaction (AR. Astaxanthin (Asta, a photo-protective red pigment belonging to the carotenoid family, is recognized as having anti-oxidant, anti-cancer, anti-diabetic and anti-inflammatory properties and is present in many dietary supplements. This study evaluates the effect of Asta in a capacitating buffer which induces low ROS production and low percentages of acrosome-reacted cells (ARC. Sperm cells were incubated in the presence or absence of increasing concentrations of Asta or diamide (Diam and analyzed for their ROS production, Tyr-phosphorylation (Tyr-P pattern and percentages of ARC and non-viable cells (NVC. Results show that Asta ameliorated both sperm head Tyr-P and ARC values without affecting the ROS generation curve, whereas Diam succeeded in enhancing the Tyr-P level but only of the flagellum without increasing ARC values. It is suggested that Asta can be inserted in the membrane and therefore create capacitation-like membrane alteration which allow Tyr-P of the head. Once this has occurred, AR can take place and involves a higher numbers of cells.

  10. Effect of astaxanthin on human sperm capacitation.

    Science.gov (United States)

    Donà, Gabriella; Kožuh, Ivana; Brunati, Anna Maria; Andrisani, Alessandra; Ambrosini, Guido; Bonanni, Guglielmo; Ragazzi, Eugenio; Armanini, Decio; Clari, Giulio; Bordin, Luciana

    2013-06-03

    In order to be able to fertilize oocytes, human sperm must undergo a series of morphological and structural alterations, known as capacitation. It has been shown that the production of endogenous sperm reactive oxygen species (ROS) plays a key role in causing cells to undergo a massive acrosome reaction (AR). Astaxanthin (Asta), a photo-protective red pigment belonging to the carotenoid family, is recognized as having anti-oxidant, anti-cancer, anti-diabetic and anti-inflammatory properties and is present in many dietary supplements. This study evaluates the effect of Asta in a capacitating buffer which induces low ROS production and low percentages of acrosome-reacted cells (ARC). Sperm cells were incubated in the presence or absence of increasing concentrations of Asta or diamide (Diam) and analyzed for their ROS production, Tyr-phosphorylation (Tyr-P) pattern and percentages of ARC and non-viable cells (NVC). Results show that Asta ameliorated both sperm head Tyr-P and ARC values without affecting the ROS generation curve, whereas Diam succeeded in enhancing the Tyr-P level but only of the flagellum without increasing ARC values. It is suggested that Asta can be inserted in the membrane and therefore create capacitation-like membrane alteration which allow Tyr-P of the head. Once this has occurred, AR can take place and involves a higher numbers of cells.

  11. Fatty acids attached to all-trans-astaxanthin alter its cis-trans equilibrium, and consequently its stability, upon light-accelerated autoxidation

    NARCIS (Netherlands)

    Bruijn, De Wouter J.C.; Weesepoel, Y.; Vincken, J.P.; Gruppen, H.

    2016-01-01

    Fatty acid esterification, common in naturally occurring astaxanthin, has been suggested to influence both colour stability and degradation of all-trans-astaxanthin. Therefore, astaxanthin stability was studied as influenced by monoesterification and diesterification with palmitate. Increased

  12. Dynamical Local Chirality and Chiral Symmetry Breaking

    CERN Document Server

    Alexandru, Andrei

    2013-01-01

    We present some of the reasoning and results substantiating the notion that spontaneous chiral symmetry breaking (SChSB) in QCD is encoded in local chiral properties of Dirac eigenmodes. Such association is possible when viewing chirality as a dynamical effect, measured with respect to the benchmark of statistically independent left-right components. Following this rationale leads to describing local chiral behavior by a taylor-made correlation, namely the recently introduced correlation coefficient of polarization C_A. In this language, correlated modes (C_A>0) show dynamical preference for local chirality while anti-correlated modes (C_A<0) favor anti-chirality. Our conclusion is that SChSB in QCD can be viewed as dominance of low-energy correlation (chirality) over anti-correlation (anti-chirality) of Dirac sea. The spectral range of local chirality, chiral polarization scale Lambda_ch, is a dynamically generated scale in the theory associated with SChSB. One implication of these findings is briefly dis...

  13. Astaxanthin: Sources, Extraction, Stability, Biological Activities and Its Commercial Applications—A Review

    Directory of Open Access Journals (Sweden)

    Ranga Rao Ambati

    2014-01-01

    Full Text Available There is currently much interest in biological active compounds derived from natural resources, especially compounds that can efficiently act on molecular targets, which are involved in various diseases. Astaxanthin (3,3′-dihydroxy-β, β′-carotene-4,4′-dione is a xanthophyll carotenoid, contained in Haematococcus pluvialis, Chlorella zofingiensis, Chlorococcum, and Phaffia rhodozyma. It accumulates up to 3.8% on the dry weight basis in H. pluvialis. Our recent published data on astaxanthin extraction, analysis, stability studies, and its biological activities results were added to this review paper. Based on our results and current literature, astaxanthin showed potential biological activity in in vitro and in vivo models. These studies emphasize the influence of astaxanthin and its beneficial effects on the metabolism in animals and humans. Bioavailability of astaxanthin in animals was enhanced after feeding Haematococcus biomass as a source of astaxanthin. Astaxanthin, used as a nutritional supplement, antioxidant and anticancer agent, prevents diabetes, cardiovascular diseases, and neurodegenerative disorders, and also stimulates immunization. Astaxanthin products are used for commercial applications in the dosage forms as tablets, capsules, syrups, oils, soft gels, creams, biomass and granulated powders. Astaxanthin patent applications are available in food, feed and nutraceutical applications. The current review provides up-to-date information on astaxanthin sources, extraction, analysis, stability, biological activities, health benefits and special attention paid to its commercial applications.

  14. Engineering of Yarrowia lipolytica for production of astaxanthin

    DEFF Research Database (Denmark)

    Kildegaard, Kanchana Rueksomtawin; Adiego Pérez, Belén; Doménech Belda, David

    2017-01-01

    for de novo production of astaxanthin by fermentation. First, we screened 12 different Y. lipolytica isolates for β-carotene production by introducing two genes for β-carotene biosynthesis: bi-functional phytoene synthase/lycopene cyclase (crtYB) and phytoene desaturase (crtI) from the red yeast...

  15. Multi-spectral Image Analysis for Astaxanthin Coating Classification

    DEFF Research Database (Denmark)

    Ljungqvist, Martin Georg; Ersbøll, Bjarne Kjær; Nielsen, Michael Engelbrecht

    2011-01-01

    Industrial quality inspection using image analysis on astaxanthin coating in aquaculture feed pellets is of great importance for automatic production control. In this study multi-spectral image analysis of pellets was performed using LDA, QDA, SNV and PCA on pixel level and mean value of pixels...

  16. Green Approaches to Extract Astaxanthin from Shrimp Waste

    DEFF Research Database (Denmark)

    Razi Parjikolaei, Behnaz; Errico, Massimiliano; El-Houri, Rime Bahij

    2016-01-01

    Sunflower oil and its methyl ester have recently been shown as potential green solvents which could substitute traditional organic solvents. This study investigates the economic feasibility of using these green solvents to extract astaxanthin from shrimp processing waste. The feasibility of comme......Sunflower oil and its methyl ester have recently been shown as potential green solvents which could substitute traditional organic solvents. This study investigates the economic feasibility of using these green solvents to extract astaxanthin from shrimp processing waste. The feasibility...... of commercial use of the green solvents under plausible process conditions is compared to extraction with a mixture of hexane: isopropanol. Process flowsheets describing these processes were created using SuperPro Designer. Although the astaxanthin extraction yield was highest when using hexane: isopropanol......, according to the economic analysis, the green solvents showed lower capital and operating costs. Extraction with methyl ester of sunflower oil was found to be the more efficient green solvent process investigated with respect to production rate and unit cost of concentrated astaxanthin (155 ppm)....

  17. Projected shell model description for nuclear isomers

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Y. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, Popular Republic (China)

    2008-12-15

    The study of nuclear isomer properties is a current research focus. To describe isomers, we present a method based on the Projected Shell Model. Two kinds of isomers, {kappa}-isomers and shape isomers, are discussed. For the {kappa}-isomer treatment, {kappa}-mixing is properly implemented in the model. It is found however that in order to describe the strong {kappa}-violation more efficiently, it may be necessary to further introduce triaxiality into the shell model basis. To treat shape isomers, a scheme is outlined which allows mixing those configurations belonging to different shapes. (Author)

  18. Effect of storage on oxidative quality and stability of extruded astaxanthin-coated fish feed pellets

    DEFF Research Database (Denmark)

    Dethlefsen, Markus Wied; Hjermitslev, Niels Harthøj; Frosch, Stina

    2016-01-01

    This study examined the stability of extruded and astaxanthin-coated fish feed pellets during storage in a light box at 28°C and 620lx. Seven groups of fish feed pellets were vacuum coated with fish oil that contained levels of astaxanthin ranging from 0 to 100ppm. To equalize differences...... in the conditions for the fish feed pellets inside the light box, the samples were systematically circled during the experimental storage period of 183days. The degradation of astaxanthin was monitored using multi-spectral images, captured 28 times in the course of the storage period. Additionally, samples were...... collected at storage day 8, 15, 22, 92 and 183 for chemical determination of the astaxanthin concentration. The degradation of astaxanthin was shown to primarily be affected by light and limited to occur at the surface of the fish feed pellets, whereas the astaxanthin embedded in the core of the pellets...

  19. Chiral Inorganic Nanostructures.

    Science.gov (United States)

    Ma, Wei; Xu, Liguang; de Moura, André F; Wu, Xiaoling; Kuang, Hua; Xu, Chuanlai; Kotov, Nicholas A

    2017-06-28

    The field of chiral inorganic nanostructures is rapidly expanding. It started from the observation of strong circular dichroism during the synthesis of individual nanoparticles (NPs) and their assemblies and expanded to sophisticated synthetic protocols involving nanostructures from metals, semiconductors, ceramics, and nanocarbons. Besides the well-established chirality transfer from bioorganic molecules, other methods to impart handedness to nanoscale matter specific to inorganic materials were discovered, including three-dimentional lithography, multiphoton chirality transfer, polarization effects in nanoscale assemblies, and others. Multiple chiral geometries were observed with characteristic scales from ångströms to microns. Uniquely high values of chiral anisotropy factors that spurred the development of the field and differentiate it from chiral structures studied before, are now well understood; they originate from strong resonances of incident electromagnetic waves with plasmonic and excitonic states typical for metals and semiconductors. At the same time, distinct similarities with chiral supramolecular and biological systems also emerged. They can be seen in the synthesis and separation methods, chemical properties of individual NPs, geometries of the nanoparticle assemblies, and interactions with biological membranes. Their analysis can help us understand in greater depth the role of chiral asymmetry in nature inclusive of both earth and space. Consideration of both differences and similarities between chiral inorganic, organic, and biological nanostructures will also accelerate the development of technologies based on chiroplasmonic and chiroexcitonic effects. This review will cover both experiment and theory of chiral nanostructures starting with the origin and multiple components of mirror asymmetry of individual NPs and their assemblies. We shall consider four different types of chirality in nanostructures and related physical, chemical, and

  20. Biomarkers of Oxidative Stress in the Assessment of Enantioselective Toxicity of Chiral Pesticides.

    Science.gov (United States)

    Ye, Xiaoqing; Liu, Ying; Li, Feixue

    2017-01-01

    In biological systems, the individual stereoisomers of chiral substances possess significantly different biochemical properties because the specific structure-activity relationships are required for a common site on biomolecules. In the past decade, there has been increasing concern over the enantioselective toxicity of environmental chiral pollutants, especially chiral pesticides. Different responses and activities of a pair of enantiomers of chiral pesticides were often observed. Therefore, assessment of the enantioselective toxicological properties of chiral pesticides is a prerequisite in application of single-isomer products and particularly important for environmental protection. The development of biomarkers that can predict enantioselective effects from chiral pesticides has recently been gained more and more attention. The biomarkers of oxidative stress have become a topic of significant interest for toxic assessments. In this review, we summarized current knowledge and advances in the understanding of enantiomeric oxidative processes in biological systems in response to chiral pesticides. The consistent results in two types of chiral insecticides (synthetic pyrethroids and organochlorine pesticides) showed the significant difference in cytotoxicity of enantiomers, suggesting the antioxidant enzymes are reliable biomarkers for the assessment of toxicity of chiral chemicals. Results indicate that antioxidant enzymes are sensitive and valid biomarkers to assess the oxidative damage caused by chiral herbicides. In addition, it can be inferred that the enantioselectivity of chiral herbicides on antioxidant enzymes exists in other species. Compared with insecticides and herbicides, researches about the enantioselectivity of oxidative stress caused by chiral fungicides are quite limited. Only two kinds of chiral fungicides has been used to study the enantioselectivity of oxidative stress by now. The current knowledge that enantioselective processes of oxidative

  1. Formulation of a fish feed for goldfish with natural astaxanthin extracted from shrimp waste

    National Research Council Canada - National Science Library

    Weeratunge, W K. O. V; Perera, B G. K

    2016-01-01

    .... An attempt was made towards optimization of astaxanthin extraction conditions using three different extraction conditions and a solvent series, from uncooked, cooked and acid-treated shrimp waste...

  2. Enhancing Photon Utilization Efficiency for Astaxanthin Production from Haematococcus lacustris Using a Split-Column Photobioreactor.

    Science.gov (United States)

    Kim, Z-Hun; Park, Hanwool; Lee, Ho-Sang; Lee, Choul-Gyun

    2016-07-28

    A split-column photobioreactor (SC-PBR), consisting of two bubble columns with different sizes, was developed to enhance the photon utilization efficiency in an astaxanthin production process from Haematococcus lacustris. Among the two columns, only the smaller column of SC-PBR was illuminated. Astaxanthin productivities and photon efficiencies of the SC-PBRs were compared with a standard bubble-column PBR (BC-PBR). Astaxanthin productivity of SC-PBR was improved by 28%, and the photon utilization efficiencies were 28-366% higher than the original BC-PBR. The results clearly show that the effective light regime of SC-PBR could enhance the production of astaxanthin.

  3. Introduction to chiral symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Koch, V.

    1996-01-08

    These lectures are an attempt to a pedagogical introduction into the elementary concepts of chiral symmetry in nuclear physics. Effective chiral models such as the linear and nonlinear sigma model will be discussed as well as the essential ideas of chiral perturbation theory. Some applications to the physics of ultrarelativistic heavy ion collisions will be presented.

  4. Introduction to Chiral Symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Volker [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-05-09

    These lectures are an attempt to a pedagogical introduction into the elementary concepts of chiral symmetry in nuclear physics. We will also discuss some effective chiral models such as the linear and nonlinear sigma model as well as the essential ideas of chiral perturbation theory. We will present some applications to the physics of ultrarelativistic heavy ion collisionsd.

  5. Molecular spinning by a chiral train of short laser pulses

    Science.gov (United States)

    Floß, Johannes; Averbukh, Ilya Sh.

    2012-12-01

    We provide a detailed theoretical analysis of molecular rotational excitation by a chiral pulse train, a sequence of linearly polarized pulses with the polarization direction rotating from pulse to pulse by a controllable angle. Molecular rotation with a preferential rotational sense (clockwise or counterclockwise) can be excited by this scheme. We show that the directionality of the rotation is caused by quantum interference of different excitation pathways. The chiral pulse train is capable of selective excitation of molecular isotopologs and nuclear spin isomers in a mixture. We demonstrate this using 14N2 and 15N2 as examples for isotopologs and para- and ortho-nitrogen as examples for nuclear-spin isomers.

  6. Stereospecific Synthesis of Two Isomers of (4,8 - Dimethyldecanal: The Aggregation Pheromone of Tribolium spp

    Directory of Open Access Journals (Sweden)

    Zarbin Paulo H.G.

    1998-01-01

    Full Text Available A straightforward stereospecific synthesis of two stereoisomers, (4R, 8S and (4S, 8S, of 4,8-dimethyldecanal (1, out of four possible isomers, is described. The key step employs the coupling reaction of tosylates (3 and (3a, which are obtained from (R- and (S- citronellol, with the chiral Grignard reagent prepared from comercial (S-(+-1-bromo-2-methylbutane (4.

  7. On chiral and non chiral 1D supermultiplets

    Energy Technology Data Exchange (ETDEWEB)

    Toppan, Francesco, E-mail: toppan@cbpf.b [Centro Brasileiro de Pesquisas Fisicas (TEO/CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Fisica Teorica

    2011-07-01

    In this talk I discuss and clarify some issues concerning chiral and non chiral properties of the one-dimensional supermultiplets of the N-extended supersymmetry. Quaternionic chirality can be defined for N = 4, 5, 6, 7, 8. Octonionic chirality for N = 8 and beyond. Inequivalent chiralities only arise when considering several copies of N = 4 or N = 8 supermultiplets. (author)

  8. Chiral symmetry and chiral-symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Peskin, M.E.

    1982-12-01

    These lectures concern the dynamics of fermions in strong interaction with gauge fields. Systems of fermions coupled by gauge forces have a very rich structure of global symmetries, which are called chiral symmetries. These lectures will focus on the realization of chiral symmetries and the causes and consequences of thier spontaneous breaking. A brief introduction to the basic formalism and concepts of chiral symmetry breaking is given, then some explicit calculations of chiral symmetry breaking in gauge theories are given, treating first parity-invariant and then chiral models. These calculations are meant to be illustrative rather than accurate; they make use of unjustified mathematical approximations which serve to make the physics more clear. Some formal constraints on chiral symmetry breaking are discussed which illuminate and extend the results of our more explicit analysis. Finally, a brief review of the phenomenological theory of chiral symmetry breaking is presented, and some applications of this theory to problems in weak-interaction physics are discussed. (WHK)

  9. Multiple Mechanisms of Anti-Cancer Effects Exerted by Astaxanthin

    OpenAIRE

    Li Zhang; Handong Wang

    2015-01-01

    Astaxanthin (ATX) is a xanthophyll carotenoid which has been approved by the United States Food and Drug Administration (USFDA) as food colorant in animal and fish feed. It is widely found in algae and aquatic animals and has powerful anti-oxidative activity. Previous studies have revealed that ATX, with its anti-oxidative property, is beneficial as a therapeutic agent for various diseases without any side effects or toxicity. In addition, ATX also shows preclinical anti-tumor efficacy both i...

  10. Astaxanthin production from sewage of traditional Thai rice vermicelli

    Science.gov (United States)

    Sujarit, Chutinut; Rittirut, Waigoon; Amornlerdpison, Doungporn; Siripatana, Chairat

    2017-03-01

    This research aimed to investigate an optimal condition for astaxanthin production by Phaffia rhodozyma TISTR 5730 in two different media: synthetic YM medium and the medium added with coconut water and diluted with sewage from Thai traditional rice vermicelli plant (coconut water: sewage of 1:0, 1:1, 1:3 and 1:5 ration respectively). The basic medium formulation was composed of 10 g/L glucose, 3 g/L yeast extract, 0.1 g/L K2HPO4, 0.01 g/L NaCl, 0.01 g/L MgSO4 and 0.01 g/L CaCl2 with initial pH 5.5. The cultures were cultivated on 200 rpm shaking bath at 50 °C for 120 hr. It was found that P. rhodozyma TISTR 5370 grew optimally when cultivated in a mixture of coconut water and Thai rice vermicelli sewage (ratio of 1:3), with growth of 3.23 g dry biomass/L and specific astaxanthin production of 680 μg/g dry cell respectively. When fan palm sugar was added to increase reducing sugar from 10 to 15, 20 and 25 g/L, it was demonstrated that the 15 g/L formulation produced highest both dry cell weight (9.66 g/L) and astaxanthin (810 μg/g dry cell weight). Furthermore, when 0.5, 1.0 and 1.5 g/L citric acid was added as supplement, it was found that 1.0-g/L citric acid formulation gave the best result: 10.30 g/L dried cell weight and 930 μg/g dry cell weight astaxanthin. This study provides a promising alternative method of sewage reduction and valorization of wastewater from Thai traditional rice vermicelli plant.

  11. Protective effects of astaxanthin from Paracoccus carotinifaciens on murine gastric ulcer models.

    Science.gov (United States)

    Murata, Kenta; Oyagi, Atsushi; Takahira, Dai; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Ishibashi, Takashi; Hara, Hideaki

    2012-08-01

    The purpose of this study was to investigate the effect of astaxanthin extracted from Paracoccus carotinifaciens on gastric mucosal damage in murine gastric ulcer models. Mice were pretreated with astaxanthin for 1 h before ulcer induction. Gastric ulcers were induced in mice by oral administration of hydrochloride (HCl)/ethanol or acidified aspirin. The effect of astaxanthin on lipid peroxidation in murine stomach homogenates was also evaluated by measuring the level of thiobarbituric acid reactive substance (TBARS). The free radical scavenging activities of astaxanthin were also measured by electron spin resonance (ESR) measurements. Astaxanthin significantly decreased the extent of HCl/ethanol- and acidified aspirin-induced gastric ulcers. Astaxanthin also decreased the level of TBARS. The ESR measurement showed that astaxanthin had radical scavenging activities against the 1,1-diphenyl-2-picrylhydrazyl radical and the superoxide anion radical. These results suggest that astaxanthin has antioxidant properties and exerts a protective effect against ulcer formation in murine models. Copyright © 2011 John Wiley & Sons, Ltd.

  12. Metabolic engineering of astaxanthin biosynthesis in maize endosperm and characterization of a prototype high oil hybrid.

    Science.gov (United States)

    Farré, Gemma; Perez-Fons, Laura; Decourcelle, Mathilde; Breitenbach, Jürgen; Hem, Sonia; Zhu, Changfu; Capell, Teresa; Christou, Paul; Fraser, Paul D; Sandmann, Gerhard

    2016-08-01

    Maize was genetically engineered for the biosynthesis of the high value carotenoid astaxanthin in the kernel endosperm. Introduction of a β-carotene hydroxylase and a β-carotene ketolase into a white maize genetic background extended the carotenoid pathway to astaxanthin. Simultaneously, phytoene synthase, the controlling enzyme of carotenogenesis, was over-expressed for enhanced carotenoid production and lycopene ε-cyclase was knocked-down to direct more precursors into the β-branch of the extended ketocarotenoid pathway which ends with astaxanthin. This astaxanthin-accumulating transgenic line was crossed into a high oil- maize genotype in order to increase the storage capacity for lipophilic astaxanthin. The high oil astaxanthin hybrid was compared to its astaxanthin producing parent. We report an in depth metabolomic and proteomic analysis which revealed major up- or down- regulation of genes involved in primary metabolism. Specifically, amino acid biosynthesis and the citric acid cycle which compete with the synthesis or utilization of pyruvate and glyceraldehyde 3-phosphate, the precursors for carotenogenesis, were down-regulated. Nevertheless, principal component analysis demonstrated that this compositional change is within the range of the two wild type parents used to generate the high oil producing astaxanthin hybrid.

  13. Determination of astaxanthin concentration in Rainbow trout (Oncorhynchus mykiss) by multispectral image analysis

    DEFF Research Database (Denmark)

    Frosch, Stina; Dissing, Bjørn Skovlund; Ersbøll, Bjarne Kjær

    extraction of astaxanthin from the minced sample into a suitable solvent such as acetone or hexane before further analysis. The existing methods have several drawbacks including being destructive and labour consuming. Current state-of-the art vision systems for quality and process control in the fish......Astaxanthin is the single most expensive constituent in salmonide fish feed. Therefore control and optimization of the astaxanthin concentration from feed to fish is of paramount importance for a cost effective salmonide production. Traditionally, methods for astaxanthin determination include...... information and measurement of more biological quality parameters such as fat, astaxanthin and cartilage content, simultaneously. A multispectral image may also be referred to as a surface chemistry map where a set of neighbouring spectra are recorded, revealing information about the surface chemistry...

  14. Astaxanthin: structural and functional aspects Astaxantina: aspectos estruturais e funcionais

    Directory of Open Access Journals (Sweden)

    Larissa Mont'Alverne Jucá Seabra

    2010-12-01

    Full Text Available Astaxanthin, a carotenoid belonging to the xanthophyll class, has stirred great interest due to its antioxidant capacity and its possible role in reducing the risk of some diseases. Astaxanthin occurs naturally in microalgae, such as Haematococcus pluvialis and the yeast Phaffia rhodozyma, and has also been considered to be the major carotenoid in salmon and crustaceans. Shrimp processing waste, which is generally discarded, is also an important source of astaxanthin. The antioxidant activity of astaxanthin has been observed to modulate biological functions related to lipid peroxidation, having beneficial effects on chronic diseases such as cardiovascular disease, macular degeneration and cancer. Researches have shown that both astaxanthin obtained from natural sources and its synthetic counterpart produce satisfactory effects, but studies in humans are limited to natural sources. There is no established nutritional recommendation regarding astaxanthin daily intake but most studies reported beneficial results from a daily intake of 4mg. Thus, this review discusses some aspects of the carotenoid astaxanthin, highlighting its chemical structure and antioxidant activity, and some studies that report its use in humans.A astaxantina, carotenóide pertencente à classe das xantofilas, tem despertado grande interesse devido à sua capacidade antioxidante e possível papel na redução de risco de algumas doenças. A astaxantina pode ser encontrada naturalmente em microalgas como Haematococcus pluvialis e na levedura Phaffia rhodozyma como também tem sido considerada principal carotenóide em salmão e crustáceos. Os resíduos do processamento de camarão, geralmente descartados, são também importante fonte de astaxantina. A atividade antioxidante da astaxantina tem demonstrado importante função na modulação de funções biológicas relacionadas à peroxidação lipídica, desempenhando efeitos benéficos em doenças crônicas como doen

  15. Mechanical separation of chiral dipoles by chiral light

    CERN Document Server

    Canaguier-Durand, Antoine; Genet, Cyriaque; Ebbesen, Thomas W

    2013-01-01

    Optical forces take on a specific form when involving chiral light fields interacting with chiral objects. We show that optical chirality density and flow can have mechanical effects through reactive and dissipative components of chiral forces exerted on chiral dipoles. Remarkably, these force components are directly related to standard observables: optical rotation and circular dichroism, respectively. As a consequence, resulting forces and torques are dependent on the enantiomeric form of the chiral dipole. This leads to promising strategies for the mechanical separation of chiral objects using chiral light forces.

  16. Doped Chiral Polymer Metamaterials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Doped Chiral Polymer Metamaterials (DCPM) with tunable resonance frequencies have been developed by adding plasmonic inclusions into chiral polymers with variable...

  17. Chirality-Dependent Interaction of d- and l-Menthol with Biomembrane Models

    Directory of Open Access Journals (Sweden)

    Pooja Gusain

    2017-12-01

    Full Text Available Chirality plays a vital role in biological membranes and has a significant effect depending on the type and arrangement of the isomer. Menthol has two typical chiral forms, d- and l-, which exhibit different behaviours. l-Menthol is known for its physiological effect on sensitivity (i.e. a cooling effect, whereas d-menthol causes skin irritation. Menthol molecules may affect not only the thermoreceptors on biomembranes, but also the membrane itself. Membrane heterogeneity (lipid rafts, phase separation depends on lipid packing and acyl chain ordering. Our interest is to elaborate the chirality dependence of d- and l-menthol on membrane heterogeneity. We revealed physical differences between the two optical isomers of menthol on membrane heterogeneity by studying model membranes using nuclear magnetic resonance and microscopic observation.

  18. Competitive chiral induction in a 2D molecular assembly: Intrinsic chirality versus coadsorber-induced chirality

    Science.gov (United States)

    Chen, Ting; Li, Shu-Ying; Wang, Dong; Wan, Li-Jun

    2017-01-01

    Noncovalently introducing stereogenic information is a promising approach to embed chirality in achiral molecular systems. However, the interplay of the noncovalently introduced chirality with the intrinsic chirality of molecules or molecular aggregations has rarely been addressed. We report a competitive chiral expression of the noncovalent interaction–mediated chirality induction and the intrinsic stereogenic center–controlled chirality induction in a two-dimensional (2D) molecular assembly at the liquid/solid interface. Two enantiomorphous honeycomb networks are formed by the coassembly of an achiral 5-(benzyloxy)isophthalic acid (BIC) derivative and 1-octanol at the liquid/solid interface. The preferential formation of the globally homochiral assembly can be achieved either by using the chiral analog of 1-octanol, (S)-6-methyl-1-octanol, as a chiral coadsorber to induce chirality to the BIC assembly via noncovalent hydrogen bonding or by covalently linking a chiral center in the side chain of BIC. Both the chiral coadsorber and the intrinsically chiral BIC derivative can act as a chiral seeds to induce a preferred handedness in the assembly of the achiral BIC derivatives. Furthermore, the noncovalent interaction–mediated chirality induction can restrain or even overrule the manifestation of the intrinsic chirality of the BIC molecule and dominate the handedness of the 2D molecular coassembly. This study provides insight into the interplay of intrinsically chiral centers and external chiral coadsorbers in the chiral induction, transfer, and amplification processes of 2D molecular assembly.

  19. Astaxanthin ameliorates aluminum chloride-induced spatial memory impairment and neuronal oxidative stress in mice.

    Science.gov (United States)

    Al-Amin, Md Mamun; Reza, Hasan Mahmud; Saadi, Hasan Mahmud; Mahmud, Waich; Ibrahim, Abdirahman Adam; Alam, Musrura Mefta; Kabir, Nadia; Saifullah, A R M; Tropa, Sarjana Tarannum; Quddus, A H M Ruhul

    2016-04-15

    Aluminum chloride induces neurodegenerative disease in animal model. Evidence suggests that aluminum intake results in the activation of glial cells and generation of reactive oxygen species. By contrast, astaxanthin is an antioxidant having potential neuroprotective activity. In this study, we investigate the effect of astaxanthin on aluminum chloride-exposed behavioral brain function and neuronal oxidative stress (OS). Male Swiss albino mice (4 months old) were divided into 4 groups: (i) control (distilled water), (ii) aluminum chloride, (iii) astaxanthin+aluminum chloride, and (iv) astaxanthin. Two behavioral tests; radial arm maze and open field test were conducted, and OS markers were assayed from the brain and liver tissues following 42 days of treatment. Aluminum exposed group showed a significant reduction in spatial memory performance and anxiety-like behavior. Moreover, aluminum group exhibited a marked deterioration of oxidative markers; lipid peroxidation (MDA), nitric oxide (NO), glutathione (GSH) and advanced oxidation of protein products (AOPP) in the brain. To the contrary, co-administration of astaxanthin and aluminum has shown improved spatial memory, locomotor activity, and OS. These results indicate that astaxanthin improves aluminum-induced impaired memory performances presumably by the reduction of OS in the distinct brain regions. We suggest a future study to determine the underlying mechanism of astaxanthin in improving aluminum-exposed behavioral deficits. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Chlorella zofingiensis as an Alternative Microalgal Producer of Astaxanthin: Biology and Industrial Potential

    Directory of Open Access Journals (Sweden)

    Jin Liu

    2014-06-01

    Full Text Available Astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione, a high-value ketocarotenoid with a broad range of applications in food, feed, nutraceutical, and pharmaceutical industries, has been gaining great attention from science and the public in recent years. The green microalgae Haematococcus pluvialis and Chlorella zofingiensis represent the most promising producers of natural astaxanthin. Although H. pluvialis possesses the highest intracellular astaxanthin content and is now believed to be a good producer of astaxanthin, it has intrinsic shortcomings such as slow growth rate, low biomass yield, and a high light requirement. In contrast, C. zofingiensis grows fast phototrophically, heterotrophically and mixtrophically, is easy to be cultured and scaled up both indoors and outdoors, and can achieve ultrahigh cell densities. These robust biotechnological traits provide C. zofingiensis with high potential to be a better organism than H. pluvialis for mass astaxanthin production. This review aims to provide an overview of the biology and industrial potential of C. zofingiensis as an alternative astaxanthin producer. The path forward for further expansion of the astaxanthin production from C. zofingiensis with respect to both challenges and opportunities is also discussed.

  1. Astaxanthin from Haematococcus pluvialis Prevents Oxidative Stress on Human Endothelial Cells without Toxicity

    Science.gov (United States)

    Régnier, Philippe; Bastias, Jorge; Rodriguez-Ruiz, Violeta; Caballero-Casero, Noelia; Caballo, Carmen; Sicilia, Dolores; Fuentes, Axelle; Maire, Murielle; Crepin, Michel; Letourneur, Didier; Gueguen, Virginie; Rubio, Soledad; Pavon-Djavid, Graciela

    2015-01-01

    Astaxanthin, a powerful antioxidant, is a good candidate for the prevention of intracellular oxidative stress. The aim of the study was to compare the antioxidant activity of astaxanthin present in two natural extracts from Haematococcus pluvialis, a microalgae strain, with that of synthetic astaxanthin. Natural extracts were obtained either by solvent or supercritical extraction methods. UV, HPLC-DAD and (HPLC-(atmospheric pressure chemical ionization (APCI)+)/ion trap-MS) characterizations of both natural extracts showed similar compositions of carotenoids, but different percentages in free astaxanthin and its ester derivatives. The Trolox equivalent antioxidant capacity (TEAC) assay showed that natural extracts containing esters displayed stronger antioxidant activities than free astaxanthin. Their antioxidant capacities to inhibit intracellular oxidative stress were then evaluated on HUVEC cells. The intracellular antioxidant activity in natural extracts was approximately 90-times higher than synthetic astaxanthin (5 µM). No modification, neither in the morphology nor in the viability, of vascular human cells was observed by in vitro biocompatibility study up to 10 µM astaxanthin concentrations. Therefore, these results revealed the therapeutic potential of the natural extracts in vascular human cell protection against oxidative stress without toxicity, which could be exploited in prevention and/or treatment of cardiovascular diseases. PMID:25962124

  2. Chlorella zofingiensis as an Alternative Microalgal Producer of Astaxanthin: Biology and Industrial Potential

    Science.gov (United States)

    Liu, Jin; Sun, Zheng; Gerken, Henri; Liu, Zheng; Jiang, Yue; Chen, Feng

    2014-01-01

    Astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione), a high-value ketocarotenoid with a broad range of applications in food, feed, nutraceutical, and pharmaceutical industries, has been gaining great attention from science and the public in recent years. The green microalgae Haematococcus pluvialis and Chlorella zofingiensis represent the most promising producers of natural astaxanthin. Although H. pluvialis possesses the highest intracellular astaxanthin content and is now believed to be a good producer of astaxanthin, it has intrinsic shortcomings such as slow growth rate, low biomass yield, and a high light requirement. In contrast, C. zofingiensis grows fast phototrophically, heterotrophically and mixtrophically, is easy to be cultured and scaled up both indoors and outdoors, and can achieve ultrahigh cell densities. These robust biotechnological traits provide C. zofingiensis with high potential to be a better organism than H. pluvialis for mass astaxanthin production. This review aims to provide an overview of the biology and industrial potential of C. zofingiensis as an alternative astaxanthin producer. The path forward for further expansion of the astaxanthin production from C. zofingiensis with respect to both challenges and opportunities is also discussed. PMID:24918452

  3. EXTRACTION OF ASTAXANTHIN ESTERS FROM SHRIMP WASTE BY CHEMICAL AND MICROBIAL METHODS

    Directory of Open Access Journals (Sweden)

    A. Khanafari, A. Saberi, M. Azar, Gh. Vosooghi, Sh. Jamili, B. Sabbaghzadeh

    2007-04-01

    Full Text Available The carotenoid pigments specifically astaxanthin has many significant applications in food, pharmaceutical and cosmetic industries. The goal of this research was the extraction of Astaxanthin from a certain Persian Gulf shrimp species waste (Penaeus semisulcatus, purification and identification of the pigment by chemical and microbial methods. Microbial fermentation was obtained by inoculation of two Lactobacillus species Lb. plantarum and Lb. acidophilus in the medium culture containing shrimp waste powder by the intervention of lactose sugar, yeast extract, the composition of Both and the coolage (-20oC. The carotenoids were extracted by an organic solvent system. After purification of astaxanthin with the thin layer chromatography method by spectrophotometer, NMR and IR analysis the presence of astaxanthin esters was recognized in this specific species of Persian Gulf shrimp. Results obtained from this study showed that the coolage at –20 oC not only does not have an amplifying effect on the production of astaxanthin but also slightly reduces this effect. Also the effect of intervention of lactose sugar showed more effectiveness in producing astaxanthin than yeast extract or more than with the presence of both. The results also indicated that there is not much difference in the ability of producing the pigment by comparing both Lb. plantarum and Lb. acidophillus. Also results showed the microbial method of extraction of astaxanthin is more effective than chemical method. The pigment extracted from certain amount of shrimp powder, 23.128 mg/g, was calculated.

  4. Studies on the metabolism of astaxanthin in the rainbow trout (Salmo gairdneri)

    Energy Technology Data Exchange (ETDEWEB)

    Al-Khalifah, A.S.

    1986-01-01

    Racemic astaxanthin was fed to rainbow trout (Salmo gairdneri) for 2, 4, and 6 weeks. The fish showed a bright pink coloration of the skin and flesh; the highest amount of astaxanthin was found in the skin of fish fed the test diet for six weeks. Lutein, 3-epilutein, and zeaxanthin were also detected in the flesh and skin; it was concluded that astaxanthin was converted to zeaxanthin in the skin. The mean vitamin A content of the liver was determined; the ratio of vitamin A/sub 1/:vitamin A/sub 2/ was approximately 1:3. Retinol and 3,4-dehydroretinol were extracted from the intestine of rainbow trout low in vitamin A, after force feeding with astaxanthin using a feeding tube. Antibiotic-treated fish had no marked difference in vitamin A content compared with a control group that received no antibiotic. This proves that astaxanthin was converted to vitamin A in fish depleted of vitamin A, that microorganisms were not involved in the conversion, and that conversion occurred in the intestine. An in vitro study using /sup 3/H 3S, 3S'-astaxanthin incubated with duodenal and ileal segments of the intestine provided HLPC and radioisotope data, which showed that rainbow trout were able to bioconvert astaxanthin to vitamin A.

  5. The effective photoinduction of Haematococcus pluvialis for accumulating astaxanthin with attached cultivation.

    Science.gov (United States)

    Wan, Minxi; Hou, Dongmei; Li, Yuanguang; Fan, Jianhua; Huang, Jianke; Liang, Songtao; Wang, Weiliang; Pan, Ronghua; Wang, Jun; Li, Shulan

    2014-07-01

    As the optimal source of astaxanthin, Haematococcus pluvialis was cultured for commercial production of astaxanthin through two continuous phases: cell growth and astaxanthin induction. In this study, the efficiency of an attached system for producing astaxanthin from H. pluvialis was investigated and compared to that of the suspended system (bubble column bioreactor) under various conditions. Results showed that this attached system is more suitable for photoinduction of H. pluvialis than the suspended bioreactor. Under the optimal conditions, the astaxanthin productivity of the attached system was 65.8 mg m(-2)d(-1) and 2.4-fold of that in the suspended system. This attached approach also offers other advantages over suspended systems, such as, producing astaxanthin under a wide range of light intensities and temperatures, saving water, ease to harvest cells, resisting contamination. Therefore, the attached approach can be considered an economical, environmentally friendly and highly-efficient technology for producing astaxanthin from H. pluvialis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Astaxanthin from Haematococcus pluvialis Prevents Oxidative Stress on Human Endothelial Cells without Toxicity

    Directory of Open Access Journals (Sweden)

    Philippe Régnier

    2015-05-01

    Full Text Available Astaxanthin, a powerful antioxidant, is a good candidate for the prevention of intracellular oxidative stress. The aim of the study was to compare the antioxidant activity of astaxanthin present in two natural extracts from Haematococcus pluvialis, a microalgae strain, with that of synthetic astaxanthin. Natural extracts were obtained either by solvent or supercritical extraction methods. UV, HPLC-DAD and (HPLC-(atmospheric pressure chemical ionization (APCI+/ion trap-MS characterizations of both natural extracts showed similar compositions of carotenoids, but different percentages in free astaxanthin and its ester derivatives. The Trolox equivalent antioxidant capacity (TEAC assay showed that natural extracts containing esters displayed stronger antioxidant activities than free astaxanthin. Their antioxidant capacities to inhibit intracellular oxidative stress were then evaluated on HUVEC cells. The intracellular antioxidant activity in natural extracts was approximately 90-times higher than synthetic astaxanthin (5 µM. No modification, neither in the morphology nor in the viability, of vascular human cells was observed by in vitro biocompatibility study up to 10 µM astaxanthin concentrations. Therefore, these results revealed the therapeutic potential of the natural extracts in vascular human cell protection against oxidative stress without toxicity, which could be exploited in prevention and/or treatment of cardiovascular diseases.

  7. Formulasi dan Karakterisasi SNE (Self Nanoemulsion Astaxanthin dari Haematococcus pluvialis sebagai Super Antioksidan Alami

    Directory of Open Access Journals (Sweden)

    Lusi Nurdianti

    2017-12-01

    Full Text Available Astaxanthin merupakan kelompok karotenoid xantofil larut lemak yang banyak ditemukan pada berbagai mikroorganisme dan hewan laut. Permasalahan yang terdapat di dalam pengunaannya sebagai bahan aktif sumber antioksidan adalah karena lipofilisitasnya dan stabilitas astaxanthin yang rendah di dalam saluran cerna sehingga membuat ketersediaan hayati yang rendah. Di dalam penelitian ini menawarkan teknologi nano untuk mengembangkan nanoemulsi astaxanthin yang ditujukan untuk meningkatkan stabilitas astaxanthin di dalam sediaan dan juga kedepannya untuk mengembangkan jalur penghantaran baru dalam pemakaian antioksidan yakni melalui rute transdermal sehingga ditujukan agar penggunaan astaxanthin dapat optimal. Di dalam penelitian ini akan dibuat formulasi nanoemulsi astaxanthin untuk menghasilkan karakteristik fisik dan kimia yang baik. Nanoemulsi dibuat dengan menggunakan metode Nanoemulsi spontan (SNE. Dilakukan optimasi formula mulai dari skrining fase minyak, skrining jenis surfaktan, dan optimasi rasio fase minyak:surfaktan:kosurfaktan. Karakterisasi nanoemulsi berupa karakterisasi secara fisik meliputi ukuran globul dan indeks polidispersitas, potensial zeta, tampilan visual, dan morfologi globul. Karakterisasi secara kimia meliputi uji efisiensi penjeratan. Hasil penelitian menunjukkan nanoemulsi Astaxanthin yang dikembangkan memiliki ukuran globul 10-20 nm (dengan kurva distribusi ukuran globul normal, nilai indeks polidispersitas kurang dari 0.5, potensial zeta lebih besar dari (-20 mV, dan efisiensi penjeratan berkisar antara 80-87% serta morfologi globul yang berbentuk sferis.

  8. Metabolic Engineering of Escherichia coli for Producing Astaxanthin as the Predominant Carotenoid

    Directory of Open Access Journals (Sweden)

    Qian Lu

    2017-09-01

    Full Text Available Astaxanthin is a carotenoid of significant commercial value due to its superior antioxidant potential and wide applications in the aquaculture, food, cosmetic and pharmaceutical industries. A higher ratio of astaxanthin to the total carotenoids is required for efficient astaxanthin production. β-Carotene ketolase and hydroxylase play important roles in astaxanthin production. We first compared the conversion efficiency to astaxanthin in several β-carotene ketolases from Brevundimonas sp. SD212, Sphingomonas sp. DC18, Paracoccus sp. PC1, P. sp. N81106 and Chlamydomonas reinhardtii with the recombinant Escherichia coli cells that synthesize zeaxanthin due to the presence of the Pantoea ananatis crtEBIYZ. The B. sp. SD212 crtW and P. ananatis crtZ genes are the best combination for astaxanthin production. After balancing the activities of β-carotene ketolase and hydroxylase, an E. coli ASTA-1 that carries neither a plasmid nor an antibiotic marker was constructed to produce astaxanthin as the predominant carotenoid (96.6% with a specific content of 7.4 ± 0.3 mg/g DCW without an addition of inducer.

  9. Chiral magnetic superconductivity

    Directory of Open Access Journals (Sweden)

    Kharzeev Dmitri E.

    2017-01-01

    Full Text Available Materials with charged chiral quasiparticles in external parallel electric and magnetic fields can support an electric current that grows linearly in time, corresponding to diverging DC conductivity. From experimental viewpoint, this “Chiral Magnetic Superconductivity” (CMS is thus analogous to conventional superconductivity. However the underlying physics is entirely different – the CMS does not require a condensate of Cooper pairs breaking the gauge degeneracy, and is thus not accompanied by Meissner effect. Instead, it owes its existence to the (temperature-independent quantum chiral anomaly and the conservation of chirality. As a result, this phenomenon can be expected to survive to much higher temperatures. Even though the chirality of quasiparticles is not strictly conserved in real materials, the chiral magnetic superconductivity should still exhibit itself in AC measurements at frequencies larger than the chirality-flipping rate, and in microstructures of Dirac and Weyl semimetals with thickness below the mean chirality-flipping length that is about 1 – 100 μm. In nuclear physics, the CMS should contribute to the charge-dependent elliptic flow in heavy ion collisions.

  10. Chiral quark model

    Indian Academy of Sciences (India)

    In this talk I review studies of hadron properties in bosonized chiral quark models for the quark flavor dynamics. Mesons are constructed from Bethe–Salpeter equations and baryons emerge as chiral solitons. Such models require regularization and I show that the two-fold Pauli–Villars regularization scheme not only fully ...

  11. Astaxanthin analogs, adonixanthin and lycopene, activate Nrf2 to prevent light-induced photoreceptor degeneration.

    Science.gov (United States)

    Inoue, Yuki; Shimazawa, Masamitsu; Nagano, Ryota; Kuse, Yoshiki; Takahashi, Kei; Tsuruma, Kazuhiro; Hayashi, Masahiro; Ishibashi, Takashi; Maoka, Takashi; Hara, Hideaki

    2017-07-01

    Carotenoids, in particular astaxanthin, possess potent antioxidant capabilities. Astaxanthin also induces NF-E2-related factor 2 (Nrf2), which plays a major regulatory role in the antioxidative response. However, little is known whether the carotenoid, by-products of astaxanthin, activate Nrf2. Toward this end, we screened eight astaxanthin analogs for Nrf2 activation in murine photoreceptor cell line, 661 W, by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). In addition, we monitored cell death in 661 W cells pretreated with astaxanthin analogs or only pretreated for 6 h with astaxanthin analogs and then exposed to light. Furthermore, we quantified the reactive oxygen species (ROS) production. Cell death was quantified after light exposure by nuclear staining. Nrf2-controlled genes Ho-1, Nqo-1, and Gclm by qRT-PCR and Nrf2 in the nucleus were upregulated in 661 W cells exposed astaxanthin, adonixanthin, echinenone, and lycopene. Moreover, astaxanthin, adonixanthin, echinenone, β-carotene, adonirubin, and lycopene, but not canthaxanthin, suppressed ROS production and protected cells against light-induced damage. Moreover, pretreatment with adonixanthin or lycopene only before light exposure protected against light-induced cell damage and Nrf2 silencing canceled these effects. These findings indicate that the more potent astaxanthin analogs, adonixanthin and lycopene, protect against light-induced cell damage through not only an anti-oxidative response but also through Nrf2 activation. Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  12. Astaxanthin-Producing Green Microalga Haematococcus pluvialis: From Single Cell to High Value Commercial Products

    Science.gov (United States)

    Shah, Md. Mahfuzur R.; Liang, Yuanmei; Cheng, Jay J.; Daroch, Maurycy

    2016-01-01

    Many species of microalgae have been used as source of nutrient rich food, feed, and health promoting compounds. Among the commercially important microalgae, Haematococcus pluvialis is the richest source of natural astaxanthin which is considered as “super anti-oxidant.” Natural astaxanthin produced by H. pluvialis has significantly greater antioxidant capacity than the synthetic one. Astaxanthin has important applications in the nutraceuticals, cosmetics, food, and aquaculture industries. It is now evident that, astaxanthin can significantly reduce free radicals and oxidative stress and help human body maintain a healthy state. With extraordinary potency and increase in demand, astaxanthin is one of the high-value microalgal products of the future.This comprehensive review summarizes the most important aspects of the biology, biochemical composition, biosynthesis, and astaxanthin accumulation in the cells of H. pluvialis and its wide range of applications for humans and animals. In this paper, important and recent developments ranging from cultivation, harvest and postharvest bio-processing technologies to metabolic control and genetic engineering are reviewed in detail, focusing on biomass and astaxanthin production from this biotechnologically important microalga. Simultaneously, critical bottlenecks and major challenges in commercial scale production; current and prospective global market of H. pluvialis derived astaxanthin are also presented in a critical manner. A new biorefinery concept for H. pluvialis has been also suggested to guide toward economically sustainable approach for microalgae cultivation and processing. This report could serve as a useful guide to present current status of knowledge in the field and highlight key areas for future development of H. pluvialis astaxanthin technology and its large scale commercial implementation. PMID:27200009

  13. Astaxanthin-producing green microalga Haematococcus pluvialis: from single cell to high value commercial products

    Directory of Open Access Journals (Sweden)

    Md. Mahfuzur Rahman Shah

    2016-04-01

    Full Text Available Many species of microalgae have been used as source of nutrient rich food, feed and health promoting compounds. Among the commercially important microalgae, Haematococcus pluvialis is the richest source of natural astaxanthin which is considered as super anti-oxidant. Natural astaxanthin produced by H. pluvialis has significantly greater antioxidant capacity than the synthetic one. Astaxanthin has important applications in the nutraceuticals, cosmetics, food, and aquaculture industries. Thanks to many researches it is now evident, that astaxanthin can significantly reduce free radicals and oxidative stress and help human body maintain a healthy state. With extraordinary potency and increase in demand, astaxanthin is one of the high-value microalgal products of the future. Thus, this comprehensive review summarizes the most important aspects of the biology, biochemical composition, biosynthesis and astaxanthin accumulation in the cells of H. pluvialis and its wide range of applications for humans and animals. In this paper, important and recent developments ranging from cultivation, harvest and postharvest bio-processing technologies to metabolic control and genetic engineering are reviewed in detail, focusing on biomass and astaxanthin production from this biotechnologically important microalga. Simultaneously, critical bottlenecks and major challenges in commercial scale production; current and prospective global market of H. pluvialis derived astaxanthin are also presented in a critical manner. A new biorefinery concept for H. pluvialis has been also suggested to guide towards economically sustainable approach for microalgae cultivation and processing. This report could serve as a useful guide to present current status of knowledge in the field and highlight key areas for future development of H. pluvialis astaxanthin technology and its large scale commercial implementation.

  14. Optical chirality breaking in a bilayered chiral metamaterial.

    Science.gov (United States)

    Zhao, Jianxing; Fu, Yuegang; Liu, Zhiying; Zhou, Jianhong

    2017-09-18

    We propose a planar optical bilayered chiral metamaterial, which consists of periodic metallic arrays of two L-shaped structures and a nanorod twisted on both sides of a dielectric slab, to investigate the optical chirality breaking effect by using finite-difference time-domain (FDTD) method. Even the metamaterial is with chiral symmetry, an optical chirality breaking window in the asymmetric transmission pass band is obtained in chiral metamaterial structure. We analyze the plasmonic mode properties and attribute the mechanism of the optical chirality breaking effect to the plasmonic analogue of EIT. The optical chirality breaking window can be modulated by changing the geometric parameters of the nanorods in the structure.

  15. Gastric inflammatory markers and interleukins in patients with functional dyspepsia treated with astaxanthin

    DEFF Research Database (Denmark)

    Andersen, L.P.; Holck, Susanne; Kupcinskas, L.

    2007-01-01

    The chronic active inflammation caused by Helicobacter pylori is dominated by neutrophils, macrophages, lymphocytes and plasma cells. Several interleukins are involved in the inflammatory process. The aim of this study was to investigate the effect of astaxanthin on gastric inflammation in patients....... pylori treated with astaxanthin. Astaxanthin had an effect on the inflammation and on the density of H. pylori in mice in a study where the diet could be standardized without antioxidants (Bennedsen et al., 1999). These dietary conditions are impossible in studies involving humans, and may be due...... to the minor effect when the host have access to antioxidants in their diet....

  16. Effects of astaxanthin on antioxidant capacity of golden pompano (Trachinotus ovatus in vivo and in vitro

    Directory of Open Access Journals (Sweden)

    Jia-jun Xie

    2017-04-01

    Full Text Available Abstract The objective of this research was to study the effect of astaxanthin (AST on growth performance and antioxidant capacity in golden pompano (Trachinotus ovatus both in vivo and in vitro. In the in vivo study, two diets were formulated with or without astaxanthin supplementation (D1 and D2; 0 and 200 mg/kg to feed fish for 6 weeks. In the in vitro study, cells from hepatopancreas of golden pompano were isolated and four treatments with or without astaxanthin and H2O2 supplementation were applied (control group: without both astaxanthin and H2O2 treated; H2O2 group: just with H2O2 treated; H2O2 + AST group: with both astaxanthin and H2O2 treated; AST group: just with AST treated. Results of the in vivo study showed that weight gain (WG and special growth rate (SGR significantly increased with astaxanthin supplemented (P < 0.05. Feed conversion ratio (FCR of fish fed D2 diet was significantly lower than that of fish fed D1 diet (P < 0.05. Hepatic total antioxidant capacity (T-AOC and the reduced glutathione (GSH of golden pompano fed D2 diet were significant higher than those of fish fed D1 diet (P < 0.05. Superoxide dismutase (SOD was significantly declined as astaxanthin was supplemented (P < 0.05. Results of the in vitro study showed that the cell viability of H2O2 group was 52.37% compared to the control group, and it was significantly elevated to 84.18% by astaxanthin supplementation (H2O2 + AST group (P < 0.05. The total antioxidant capacity (T-AOC and the reduced glutathione (GSH of cell were significant decreased by oxidative stress from H2O2 (P < 0.05, but it could be raised by astaxanthin supplementation (H2O2 vs H2O2 + AST, and the malondialdehyde (MDA was significant higher in H2O2 group (P < 0.05 and astaxanthin supplementation could alleviate the cells from lipid peroxidation injury. In conclusion, dietary astaxanthin supplementation can improve the growth performance of golden

  17. Chiral separation by capillary electrochromatography.

    Science.gov (United States)

    Gübitz, G; Schmid, M G

    2000-01-01

    The state of art in chiral capillary electrochromatography is reviewed. Chiral separations by capillary electrochromatography were carried out using capillaries packed with chiral stationary phases or achiral stationary phases in combination with a chiral selector added to the mobile phase. Furthermore, the use of open tubular capillaries containing the chiral selector coated to the capillary wall was also reported. Among other separation principles moleculary imprinted polymers represent a challenging approach for chiral capillary electrochromatography. A recent trend is the use of polymeric continuous beds with a chiral selector incorporated.

  18. Applications of chiral symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Pisarski, R.D.

    1995-03-01

    The author discusses several topics in the applications of chiral symmetry at nonzero temperature. First, where does the rho go? The answer: up. The restoration of chiral symmetry at a temperature T{sub {chi}} implies that the {rho} and a{sub 1} vector mesons are degenerate in mass. In a gauged linear sigma model the {rho} mass increases with temperature, m{sub {rho}}(T{sub {chi}}) > m{sub {rho}}(0). The author conjectures that at T{sub {chi}} the thermal {rho} - a{sub 1}, peak is relatively high, at about {approximately}1 GeV, with a width approximately that at zero temperature (up to standard kinematic factors). The {omega} meson also increases in mass, nearly degenerate with the {rho}, but its width grows dramatically with temperature, increasing to at least {approximately}100 MeV by T{sub {chi}}. The author also stresses how utterly remarkable the principle of vector meson dominance is, when viewed from the modern perspective of the renormalization group. Secondly, he discusses the possible appearance of disoriented chiral condensates from {open_quotes}quenched{close_quotes} heavy ion collisions. It appears difficult to obtain large domains of disoriented chiral condensates in the standard two flavor model. This leads to the last topic, which is the phase diagram for QCD with three flavors, and its proximity to the chiral critical point. QCD may be very near this chiral critical point, and one might thereby generated large domains of disoriented chiral condensates.

  19. High spin isomer beam line at RIKEN

    Energy Technology Data Exchange (ETDEWEB)

    Kishida, T.; Ideguchi, E.; Wu, H.Y. [Institute of Physical and Chemical Research, Saitama (Japan)] [and others

    1996-12-31

    Nuclear high spin states have been the subject of extensive experimental and theoretical studies. For the production of high spin states, fusion reactions are usually used. The orbital angular momentum brought in the reaction is changed into the nuclear spin of the compound nucleus. However, the maximum induced angular momentum is limited in this mechanism by the maximum impact parameter of the fusion reaction and by the competition with fission reactions. It is, therefore, difficult to populate very high spin states, and as a result, large {gamma}-detector arrays have been developed in order to detect subtle signals from such very high spin states. The use of high spin isomers in the fusion reactions can break this limitation because the high spin isomers have their intrinsic angular momentum, which can bring the additional angular momentum without increasing the excitation energy. There are two methods to use the high spin isomers for secondary reactions: the use of the high spin isomers as a target and that as a beam. A high spin isomer target has already been developed and used for several experiments. But this method has an inevitable shortcoming that only {open_quotes}long-lived{close_quotes} isomers can be used for a target: {sup 178}Hf{sup m2} (16{sup +}) with a half-life of 31 years in the present case. By developing a high spin isomer beam, the authors can utilize various short-lived isomers with a short half-life around 1 {mu}s. The high spin isomer beam line of RIKEN Accelerator Facility is a unique apparatus in the world which provides a high spin isomer as a secondary beam. The combination of fusion-evaporation reaction and inverse kinematics are used to produce high spin isomer beams; in particular, the adoption of `inverse kinematics` is essential to use short-lived isomers as a beam.

  20. Development of chiral praziquantel analogues as potential drug candidates with activity to juvenile Schistosoma japonicum.

    Science.gov (United States)

    Zheng, Yang; Dong, LanLan; Hu, Changyan; Zhao, Bo; Yang, Chunhua; Xia, Chaoming; Sun, Dequn

    2014-09-01

    A series of chiral praziquantel analogues were synthesized and evaluated against Schistosoma japonicum both in vitro and in vivo. All compounds exhibited low to considerable good activity in vivo. Remarkably, worm reduction rate of R-3 was 60.0% at a single oral dose of 200mg/kg against juvenile stage of Schistosoma japonicum. The target compounds displayed in vivo antischistosomal activity against both Schistosoma japonicum and Schistosoma mansoni. Furthermore, all R-isomers displayed stronger antischistosomal activity than S-isomers in vivo, indicating R-isomers were the active enantiomers, while S-isomers were less active ones. This structure activity relationship (SAR) could have important implications in further drug development for schistosomiasis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Spectral signatures of chirality

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Mortensen, Asger

    2009-01-01

    We present a new way of measuring chirality, via the spectral shift of photonic band gaps in one-dimensional structures. We derive an explicit mapping of the problem of oblique incidence of circularly polarized light on a chiral one-dimensional photonic crystal with negligible index contrast...... to the formally equivalent problem of linearly polarized light incident on-axis on a non-chiral structure with index contrast. We derive analytical expressions for the first-order shifts of the band gaps for negligible index contrast. These are modified to give good approximations to the band gap shifts also...

  2. Synthesis, analytical characterization and capillary electrophoretic use of the single-isomer heptakis-(6-O-sulfobutyl)-beta-cyclodextrin.

    Science.gov (United States)

    Malanga, Milo; Fejős, Ida; Varga, Erzsébet; Benkovics, Gábor; Darcsi, András; Szemán, Julianna; Béni, Szabolcs

    2017-09-08

    This contribution reports the synthesis, characterization and capillary electrophoretic application of heptakis-(6-O-sulfobutyl-ether)-β-cyclodextrin sodium salt, (6-(SB)7-β-CD). The compound was obtained through a five-steps synthesis and it represents the first example of single-isomer sulfobutylated cyclodextrin that carries the negatively charged functions exclusively on its primary side and it is unmodified on the lower rim. The purity of each intermediate was determined by appropriate liquid chromatographic methods, while the isomeric purity of the final product was established by an ad-hoc developed HPLC method based on a CD-Screen-IEC column. The structural identification of 6-(SB)7-β-CD was carried out by 1D, 2D NMR spectroscopy and ESI-MS. The chiral separation ability of 6-(SB)7-β-CD was studied by chiral capillary electrophoresis using the single-isomer host as a background electrolyte additive to separate the enantiomers of a representative set of pharmacologically significant model compounds such as verapamil, dapoxetine, ondansetron, propranolol, atenolol, metoprolol, carvedilol, terbutaline, amlodipine and tadalafil. The enantiomer migration order and the effects of the selector concentration on the enantiorecognition properties were investigated. NMR spectroscopy was applied to deepen and further confirm the host-guest interactions and in the case of the model compound dapoxetine a potential representation for the supramolecular assembly was developed based on the dataset collected by the extensive 2D NMR analysis. This single-isomer chiral selector offers a new alternative to the widely applied randomly sulfobutylated- and sulfated-beta-cylodextrins as well as to the single-isomer sulfated and carboxymethylated derivatives in chiral separations. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Simultaneous Production of Triacylglycerol and High-Value Carotenoids by the Astaxanthin-Producing Oleaginous Green Microalga Chlorella zofingiensis

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jin; Mao, Xuemei; Zhou, Wenguang; Guarnieri, Michael T.

    2016-08-01

    The production of lipids and astaxanthin, a high-value carotenoid, by Chlorella zofingiensis was investigated under different culture conditions. Comparative analysis revealed a good correlation between triacylglycerol (TAG) and astaxanthin accumulation in C. zofingiensis. Stress conditions promoted cell size and weight and induced the accumulation of neutral lipids, especially TAG and astaxanthin, with a concomitant decrease in membrane lipids. The highest contents of TAG and astaxanthin achieved were 387 and 4.89 mg g-1 dry weight, respectively. A semi-continuous culture strategy was developed to optimize the TAG and astaxanthin productivities, which reached 297 and 3.3 mg L-1 day-1, respectively. Additionally, astaxanthin accumulation was enhanced by inhibiting de novo fatty acid biosynthesis. In summary, our study represents a pioneering work of utilizing Chlorella for the integrated production of lipids and high-value products and C. zofingiensis has great potential to be a promising production strain and serve as an emerging oleaginous model alga.

  4. Effect of feeding methods on the astaxanthin production by Phaffia rhodozyma in fed-batch process

    National Research Council Canada - National Science Library

    Danilo Gomes Moriel; Miriam Blumel Chociai; Iara Maria Pereira Machado; José Domingos Fontana; Tania Maria Bordin Bonfim

    2005-01-01

    The effect of feeding methods on the production of astaxanthin by the yeast Phaffia rhodozyma ATCC 24202 was studied, using continuous and pulsed fed-batch processes and low cost materials as substrates...

  5. Study on the relationship between intracellular metabolites and astaxanthin accumulation during Phaffia rhodozyma fermentation

    Directory of Open Access Journals (Sweden)

    Anfeng Xiao

    2015-05-01

    Conclusions: The results indicated that the accumulation of ethanol, intracellular protein, and fatty acids had competition effects on astaxanthin synthesis. This condition may explain why the P. rhodozyma strains JMU-VDL668 and JMU-7B12 achieved relatively lower astaxanthin production (1.7 and 1.2 mg/L than the other two strains JMU-MVP14 and JMU-17W (20.4 and 3.9 mg/L.

  6. Near-Infrared Hyper-spectral Image Analysis of Astaxanthin Concentration in Fish Feed Coating

    DEFF Research Database (Denmark)

    Ljungqvist, Martin Georg; Ersbøll, Bjarne Kjær; Kobayashi, K.

    2012-01-01

    The aim of this study was to investigate the possibility of predicting concentration levels of synthetic astaxanthin coating of aquaculture feed pellets by hyper-spectral image analysis in the near infra-red (NIR) range and optical filter design. The imaging devices used were a VideometerLab with...... for prediction of the concentration level. The results show that it is possible to predict the level of synthetic astaxanthin coating using either hyper-spectral imaging or three bandpass filters (BPF)....

  7. Chiral Brownian heat pump

    OpenAIRE

    van den Broek, Martijn; Van den Broeck, Christian

    2008-01-01

    We present the exact analysis of a chiral Brownian motor and heat pump. Optimization of the construction predicts, for a nanoscale device, frequencies of the order of kHz and cooling rates of the order of femtojoule per second.

  8. Chiral brownian heat pump.

    Science.gov (United States)

    van den Broek, M; Van den Broeck, C

    2008-04-04

    We present the exact analysis of a chiral Brownian motor and heat pump. Optimization of the construction predicts, for a nanoscale device, frequencies of the order of kHz and cooling rates of the order of femtojoule per second.

  9. Chiral Brownian heat pump

    OpenAIRE

    Broek, M. van den; Broeck, C. Van Den

    2007-01-01

    We present the exact analysis of a chiral Brownian motor and heat pump. Optimization of the construction predicts, for a nanoscale device, frequencies of the order of kHz and cooling rates of the order of femtojoule per second.

  10. Effect of drying, storage temperature and air exposure on astaxanthin stability from Haematococcus pluvialis.

    Science.gov (United States)

    Ahmed, Faruq; Li, Yan; Fanning, Kent; Netzel, Michael; Schenk, Peer M

    2015-08-01

    Astaxanthin is a powerful antioxidant with various health benefits such as prevention of age-related macular degeneration and improvement of the immune system, liver and heart function. To improve the post-harvesting stability of astaxanthin used in food, feed and nutraceutical industries, the biomass of the high astaxanthin producing alga Haematococcus pluvialis was dried by spray- or freeze-drying and under vacuum or air at -20°C to 37°C for 20weeks. Freeze-drying led to 41% higher astaxanthin recovery compared to commonly-used spray-drying. Low storage temperature (-20°C, 4°C) and vacuum-packing also showed higher astaxanthin stability with as little as 12.3±3.1% degradation during 20weeks of storage. Cost-benefit analysis showed that freeze-drying followed by vacuum-packed storage at -20°C can generate AUD$600 higher profit compared to spray-drying from 100kgH. pluvialis powder. Therefore, freeze-drying can be suggested as a mild and more profitable method for ensuring longer shelf life of astaxanthin from H. pluvialis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Determination of astaxanthin in Haematococcus pluvialis by first-order derivative spectrophotometry.

    Science.gov (United States)

    Liu, Xiao Juan; Juan, Liu Xiao; Wu, Ying Hua; Hua, Wu Ying; Zhao, Li Chao; Chao, Zhao Li; Xiao, Su Yao; Yao, Xiao Su; Zhou, Ai Mei; Mei, Zhou Ai; Liu, Xin; Xin, Liu

    2011-01-01

    A highly selective, convenient, and precise method, first-order derivative spectrophotometry, was applied for the determination of astaxanthin in Haematococcus pluvialis. Ethyl acetate and ethanol (1:1, v/v) were found to be the best extraction solvent tested due to their high efficiency and low toxicity compared with nine other organic solvents. Astaxanthin coexisting with chlorophyll and beta-carotene was analyzed by first-order derivative spectrophotometry in order to optimize the conditions for the determination of astaxanthin. The results show that when detected at 432 nm, the interfering substances could be eliminated. The dynamic linear range was 2.0-8.0 microg/mL, with a correlation coefficient of 0.9916. The detection threshold was 0.41 microg/mL. The RSD for the determination of astaxanthin was in the range of 0.01-0.06%; the results of recovery test were 98.1-108.0%. The statistical analysis between first-order derivative spectrophotometry and HPLC by T-testing did not exceed their critical values, revealing no significant differences between these two methods. It was proved that first-order derivative spectrophotometry is a rapid and convenient method for the determination of astaxanthin in H. pluvialis that can eliminate the negative effect resulting from the coexistence of astaxanthin with chlorophyll and beta-carotene.

  12. Secondary ketocarotenoid astaxanthin biosynthesis in algae: a multifunctional response to stress.

    Science.gov (United States)

    Lemoine, Yves; Schoefs, Benoît

    2010-11-01

    Under stressful environments, many green algae such as Haematococcus pluvialis accumulate secondary ketocarotenoids such as canthaxanthin and astaxanthin. The carotenogenesis, responsible for natural phenomena such as red snows, generally accompanies larger metabolic changes as well as morphological modifications, i.e., the conversion of the green flagellated macrozoids into large red cysts. Astaxanthin accumulation constitutes a convenient way to store energy and carbon, which will be used for further synthesis under less stressful conditions. Besides this, the presence of high amount of astaxanthin enhances the cell resistance to oxidative stress generated by unfavorable environmental conditions including excess light, UV-B irradiation, and nutrition stress and, therefore, confers a higher survival capacity to the cells. This better resistance results from the quenching of oxygen atoms for the synthesis itself as well as from the antioxidant properties of the astaxanthin molecules. Therefore, astaxanthin synthesis corresponds to a multifunctional response to stress. In this contribution, the various biochemical, genetic, and molecular data related to the biosynthesis of ketocarotenoids by Haematococcus pluvialis and other taxa are reviewed and compared. A tentative regulatory model of the biochemical network driving astaxanthin production is proposed.

  13. Effects of nutrient supply methods and illumination with blue light emitting diodes (LEDs) on astaxanthin production by Haematococcus pluvialis.

    Science.gov (United States)

    Lababpour, Abdolmajid; Hada, Keishi; Shimahara, Kazumichi; Katsuda, Tomohisa; Katoh, Shigeo

    2004-01-01

    In order to increase the cell concentration and the accumulation of astaxanthin, the effects of nutrient concentration, pH, illumination and methods of supplying nutrients were studied for the cultivation of Haematococcus pluvialis. The replacement of media to avoid the deficiency of nutrients increased the cell concentration above 1 mg-dry cell cm(-3) without induction of astaxanthin accumulation. Illumination with blue light emitting diode lamps and nutrient starvation induced accumulation of astaxanthin, and the interactive effects of these two increased the astaxanthin concentration to 76 mug cm(-3).

  14. E/Z Isomers and Isomerization

    Science.gov (United States)

    Liaaen-Jensen, Synnøve; Lutnœes, Bjart Frode

    The natural occurrence of several carotenoid cis isomers and their biological significance were not anticipated in 1962, when the classical monograph on cis-trans isomeric carotenoids [1] was published. More recent research has demonstrated that various cis isomers occur naturally in bacteria plants, algae and invertebrate animals, and are present in human blood and tissues. The participation of cis isomers in the biosynthethic route to coloured carotenoids is well established (Volume 3, Chapter 2). Important biological functions of (15Z)-carotenoids in photosynthesis have been revealed [2]. In relation to health aspects of carotenoids, the bioavailability of cis isomers may be higher than that of the all-trans isomer [3], and accumulated evidence suggests that cis/trans isomerization may occur in biological tissues, particularly of lycopene (31) in human serum [4] (Volume 5, Chapter 7).

  15. Optical absorption spectra of Ag-11 isomers

    DEFF Research Database (Denmark)

    Martinez, Jose Ignacio; Fernandez, E. M.

    2009-01-01

    The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground-stale confi......The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground......-stale configuration predominantly present in the laboratory beams based on a direct comparison between the calculated photoabsorptiou response for the Ag-11 isomers and the measured spectra of medium-size silver clusters trapped in noble gas Ar and Ne matrices at different, temperatures. This assignment is confirmed...

  16. Evaluation of Antioxidant, Hypolipidemic, and Antiatherogenic Property of Lycopene and Astaxanthin in Atherosclerosis-induced Rats.

    Science.gov (United States)

    Kumar, Rajesh; Salwe, Kartik Janardan; Kumarappan, Manimekalai

    2017-01-01

    Atherosclerosis is one of the major causes of morbidity and mortality in the world. Antioxidants play a major role in prophylaxis and prevention of progression and complications of atherosclerosis. In this study, we are evaluating the antiatherosclerotic effect of two antioxidants such as astaxanthin and lycopene. After acclimatization, 24 male SD rats, 8-10 weeks old, 150 ± 10 g, maintained as per CPCSEA guidelines were divided into four groups of six rats each. Baseline values of weight lipid profile and 2-Thiobarbituric Acid Reactive Substances (TBARS) assay were taken. All the rats were fed with high cholesterol diet (HCD). HCD only, HCD + atorvastatin (50 mg/kg), HCD + lycopene (50 mg/kg), and HCD + astaxanthin (50 mg/kg) were given to control, standard, lycopene, and astaxanthin groups, respectively, through oral gavage for 45 days. The rats were sacrificed at the end of the study, blood sample collected from aorta, and then aorta was dissected for histopathology. The lipid profile showed lycopene and astaxanthin decreased total cholesterol, low-density lipoprotein-cholesterol (LDL-C), very LDL-C, and triglycerides and increased high-density lipoprotein-cholesterol level significantly (P antioxidant, antihyperlipidemic, and antiatherosclerotic property. This warrants further study for including them in the treatment of atherosclerosis. Antioxidants play a major role in prophylaxis and prevention of progression and complications of atherosclerosis.Lycopene and Astaxanthin are suitable candidates for further research in cardiovascular disease and there is paucity of studies evaluating their role in prevention of atherosclerosis.The effect of lycopene and Astaxanthin for anti-atherosclerotic property was evaluated in high cholesterol diet fed rats.The lipid profile showed lycopene and Astaxanthin decreased TC, LDL-C, VLDL-C and triglycerides and increased HDL-C level significantly (P < 0.05) compared to the control but less than atorvastatin.The TBARS value of

  17. Astaxanthin interacts with selenite and attenuates selenite-induced cataractogenesis.

    Science.gov (United States)

    Liao, Jiahn-Haur; Chen, Chien-Sheng; Maher, Timothy J; Liu, Chiung-Yueh; Lin, Mei-Hsiang; Wu, Tzu-Hua; Wu, Shih-Hsiung

    2009-03-16

    Selenite, the most commonly encountered toxic form of selenium, in overdose, is used to induce cataracts in rats. This study demonstrated that selenite, but not selenate, would interact with the carotenoid astaxanthin (ASTX), as determined using isothermal titration calorimetry and NMR. The maximum absorption of ASTX decreased with increasing selenite concentration, indicating that the conjugated system of ASTX was changed by selenite. Such interactions between ASTX and selenite were also supported by the attenuation of selenite-induced turbidity by ASTX (0-12.5 microM) in vitro. In vivo experiments also showed that ASTX attenuated selenite-induced cataractogenesis in rats. In summary, this is the first report of a direct interaction of ASTX with selenite. This interaction is supported by an in vitro assay and may be partially responsible for the ASTX observed in vivo protection against selenite-induced cataractogenesis.

  18. Putative benefits of microalgal astaxanthin on exercise and human health

    Directory of Open Access Journals (Sweden)

    Marcelo P. Barros

    2011-04-01

    Full Text Available Astaxanthin (ASTA is a pinkish-orange carotenoid produced by microalgae, but also commonly found in shrimp, lobster and salmon, which accumulate ASTA from the aquatic food chain. Numerous studies have addressed the benefits of ASTA for human health, including the inhibition of LDL oxidation, UV-photoprotection and prophylaxis of bacterial stomach ulcers. ASTA is recognized as a powerful scavenger of reactive oxygen species (ROS, especially those involved in lipid peroxidation. Both aerobic and anaerobic exercise are closely related to overproduction of ROS in muscle tissue. Post-exercise inflammatory processes can even exacerbate the oxidative stress imposed by exercise. Thus, ASTA is suggested here as a putative nutritional alternative/coadjutant for antioxidant therapy to afford additional protection to muscle tissues against oxidative damage induced by exercise, as well as for an (overall integrative redox re-balance and general human health.

  19. Chiral Random Matrix Theory and Chiral Perturbation Theory

    Energy Technology Data Exchange (ETDEWEB)

    Damgaard, Poul H, E-mail: phdamg@nbi.dk [Niels Bohr International Academy and Discovery Center, The Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen (Denmark)

    2011-04-01

    Spontaneous breaking of chiral symmetry in QCD has traditionally been inferred indirectly through low-energy theorems and comparison with experiments. Thanks to the understanding of an unexpected connection between chiral Random Matrix Theory and chiral Perturbation Theory, the spontaneous breaking of chiral symmetry in QCD can now be shown unequivocally from first principles and lattice simulations. In these lectures I give an introduction to the subject, starting with an elementary discussion of spontaneous breaking of global symmetries.

  20. Effects of astaxanthin in mice acutely infected with Trypanosoma cruzi

    Directory of Open Access Journals (Sweden)

    Contreras-Ortiz José María Eloy

    2017-01-01

    Full Text Available During Trypanosoma cruzi infection, oxidative stress is considered a contributing factor for dilated cardiomyopathy development. In this study, the effects of astaxanthin (ASTX were evaluated as an alternative drug treatment for Chagas disease in a mouse model during the acute infection phase, given its anti-inflammatory, immunomodulating, and anti-oxidative properties. ASTX was tested in vitro in parasites grown axenically and in co-culture with Vero cells. In vivo tests were performed in BALB/c mice (4–6 weeks old infected with Trypanosoma cruzi and supplemented with ASTX (10 mg/kg/day and/or nifurtimox (NFMX; 100 mg/kg/day. Results show that ASTX has some detrimental effects on axenically cultured parasites, but not when cultured with mammalian cell monolayers. In vivo, ASTX did not have any therapeutic value against acute Trypanosoma cruzi infection, used either alone or in combination with NFMX. Infected animals treated with NFMX or ASTX/NFMX survived the experimental period (60 days, while infected animals treated only with ASTX died before day 30 post-infection. ASTX did not show any effect on the control of parasitemia; however, it was associated with an increment in focal heart lymphoplasmacytic infiltration, a reduced number of amastigote nests in cardiac tissue, and less hyperplasic spleen follicles when compared to control groups. Unexpectedly, ASTX showed a negative effect in infected animals co-treated with NFMX. An increment in parasitemia duration was observed, possibly due to ASTX blocking of free radicals, an anti-parasitic mechanism of NFMX. In conclusion, astaxanthin is not recommended during the acute phase of Chagas disease, either alone or in combination with nifurtimox.

  1. Bioaccessibility and intestinal cell uptake of astaxanthin from salmon and commercial supplements.

    Science.gov (United States)

    Chitchumroonchokchai, Chureeporn; Failla, Mark L

    2017-09-01

    Although the keto-carotenoid astaxanthin (Ast) is not typically present in human plasma due to its relative scarcity in the typical diet, global consumption of salmon, the primary source of Ast in food, and Ast supplements continues to increase. The first objective of the present study was to investigate the bioaccessibility of Ast from uncooked and cooked fillets of wild and aquacultured salmon, Ast-supplements and krill oil, during simulated gastric and small intestinal digestion. Uptake of E-Ast from micelles generated during digestion of wild salmon by monolayers of Caco-2 was also monitored. Both wild and aquacultured salmon flesh contained E-Ast and Z-isomers of unesterified Ast, whereas Ast esters were the predominant form of the carotenoid in commercial supplements and krill oil. Flesh from wild salmon contained approximately 10 times more Ast than aquacultured salmon. Common styles of cooking flesh from wild and aquacultured salmon decreased Ast content by 48-57% and 35-47%, respectively. Ast in salmon flesh, supplements and krill oil was relatively stable (>80% recovery) during in vitro digestion. The efficiency of transfer of Ast into mixed micelles during digestion of uncooked wild salmon was 43%, but only 12% for uncooked acquacultured salmon. Cooking wild salmon significantly decreased Ast bioaccessibility. The relative bioaccessibility of Ast (41-67%) after digestion of oil vehicle in commercial supplements was inversely proportional to carotenoid content (3-10mg/capsule), whereas bioaccessibility of endogenous Ast in phospholipid-rich krill oil supplement was 68%. >95% of Ast in mixed micelles generated during digestion of supplements and krill oil was unesterified. Caco-2 intestinal cells accumulated 11-14% of E-Ast delivered in mixed micelles generated from digested wild salmon. Apical uptake and basolateral secretion of E-Ast by Caco-2 cells grown on inserts were greater after digestion of Ast-enriched krill oil compared to uncooked wild salmon

  2. Autoamplification of molecular chirality through the induction of supramolecular chirality

    NARCIS (Netherlands)

    van Dijken, Derk Jan; Beierle, John M.; Stuart, Marc C. A.; Szymanski, Wiktor; Browne, Wesley R.; Feringa, Ben L.

    2014-01-01

    The novel concept for the autoamplification of molecular chirality, wherein the amplification proceeds through the induction of supramolecular chirality, is presented. A solution of prochiral, ring-open diarylethenes is doped with a small amount of their chiral, ring-closed counterpart. The

  3. Chiral anomalies and differential geometry

    Energy Technology Data Exchange (ETDEWEB)

    Zumino, B.

    1983-10-01

    Some properties of chiral anomalies are described from a geometric point of view. Topics include chiral anomalies and differential forms, transformation properties of the anomalies, identification and use of the anomalies, and normalization of the anomalies. 22 references. (WHK)

  4. Superconductivity in a chiral nanotube

    Science.gov (United States)

    Qin, F.; Shi, W.; Ideue, T.; Yoshida, M.; Zak, A.; Tenne, R.; Kikitsu, T.; Inoue, D.; Hashizume, D.; Iwasa, Y.

    2017-02-01

    Chirality of materials are known to affect optical, magnetic and electric properties, causing a variety of nontrivial phenomena such as circular dichiroism for chiral molecules, magnetic Skyrmions in chiral magnets and nonreciprocal carrier transport in chiral conductors. On the other hand, effect of chirality on superconducting transport has not been known. Here we report the nonreciprocity of superconductivity--unambiguous evidence of superconductivity reflecting chiral structure in which the forward and backward supercurrent flows are not equivalent because of inversion symmetry breaking. Such superconductivity is realized via ionic gating in individual chiral nanotubes of tungsten disulfide. The nonreciprocal signal is significantly enhanced in the superconducting state, being associated with unprecedented quantum Little-Parks oscillations originating from the interference of supercurrent along the circumference of the nanotube. The present results indicate that the nonreciprocity is a viable approach toward the superconductors with chiral or noncentrosymmetric structures.

  5. Ultrafast Chiral Chromatography as the Second Dimension in Two-Dimensional Liquid Chromatography Experiments.

    Science.gov (United States)

    Barhate, Chandan L; Regalado, Erik L; Contrella, Nathan D; Lee, Joon; Jo, Junyong; Makarov, Alexey A; Armstrong, Daniel W; Welch, Christopher J

    2017-03-21

    Chromatographic separation and analysis of complex mixtures of closely related species is one of the most challenging tasks in modern pharmaceutical analysis. In recent years, two-dimensional liquid chromatography (2D-LC) has become a valuable tool for improving peak capacity and selectivity. However, the relatively slow speed of chiral separations has limited the use of chiral stationary phases (CSPs) as the second dimension in 2D-LC, especially in the comprehensive mode. Realizing that the recent revolution in the field of ultrafast enantioselective chromatography could now provide significantly faster separations, we herein report an investigation into the use of ultrafast chiral chromatography as a second dimension for 2D chromatographic separations. In this study, excellent selectivity, peak shape, and repeatability were achieved by combining achiral and chiral narrow-bore columns (2.1 mm × 100 mm and 2.1 mm × 150 mm, sub-2 and 3 μm) in the first dimension with 4.6 mm × 30 mm and 4.6 mm × 50 mm columns packed with highly efficient chiral selectors (sub-2 μm fully porous and 2.7 μm fused-core particles) in the second dimension, together with the use of 0.1% phosphoric acid/acetonitrile eluents in both dimensions. Multiple achiral × chiral and chiral × chiral 2D-LC examples (single and multiple heart-cutting, high-resolution sampling, and comprehensive) using ultrafast chiral chromatography in the second dimension are successfully applied to the separation and analysis of complex mixtures of closely related pharmaceuticals and synthetic intermediates, including chiral and achiral drugs and metabolites, constitutional isomers, stereoisomers, and organohalogenated species.

  6. Rediscovering Chirality - Role of S-Metoprolol in Cardiovascular Disease Management.

    Science.gov (United States)

    Mohan, Jagdish C; Shah, Siddharth N; Chinchansurkar, Sunny; Dey, Arindam; Jain, Rishi

    2017-06-01

    The process of drug discovery and development today encompass a myriad of paths for bringing a new therapeutic molecule that has minimal adverse effects and of optimal use to the patient. Chirality was proposed in the direction of providing a purer and safer form of drug [Ex- cetrizine and levocetrizine]. Decades have passed since the introduction of this concept and numerous chiral molecules are in existence in therapeutics, yet somehow this concept has been ignored. This review aims to rediscover the ignored facts about chirality, its benefits and clear some common myths considering the example of S-Metoprolol in the management of Hypertension and other cardiovascular diseases. Relevant articles from Pubmed, Embase, Medline and Google Scholar were searched using the terms "Chiral", "Chirality", "Enantiomers", "Isomers", "Isomerism", "Stereo-chemistry", and "S-Metoprolol". Out of 103 articles found 17 articles mentioning in general about the concept of chirality and articles on study of S-metoprolol in various cardiovascular diseases were then reviewed. Many articles mention about the importance of chirality yet the concept has not been highlighted much. Clear benefits with chiral molecules have been documented for various drug molecules few amongst them being anaesthetics, antihypertensives, antidepressants. Benefits of S-metoprolol over racemate are also clear in terms of responder rates, dose of administration and adverse effects profile in various cardiovascular diseases. Chirality is a good way forward in providing a new drug molecule which is safe with lesser pharmacokinetic and pharmacodynamics variability, lesser side effects and more potent action. S-metoprolol is chirally pure form of racemate metoprolol and has lesser side effects, is safer in patients of COPD and Diabetes who also have hypertension and comparable responder rates at half the doses when compared to racemate.

  7. Can monoatomic xenon become chiral?

    Science.gov (United States)

    Bartik, K; El Haouaj, M; Luhmer, M; Collet, A; Reisse, J

    2000-12-15

    A chiral host, cryptophane-A (1), makes even a monoatomic noble gas chiral. The interaction of xenon and 1 was monitored by (129) Xe NMR and in the presence of a chiral chemical shift reagent. © 2000 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.

  8. Doped Chiral Polymer Metamaterials

    Science.gov (United States)

    Park, Cheol (Inventor); Kang, Jin Ho (Inventor); Gordon, Keith L. (Inventor); Sauti, Godfrey (Inventor); Lowther, Sharon E. (Inventor); Bryant, Robert G. (Inventor)

    2017-01-01

    Some implementations provide a composite material that includes a first material and a second material. In some implementations, the composite material is a metamaterial. The first material includes a chiral polymer (e.g., crystalline chiral helical polymer, poly-.gamma.-benzyl-L-glutamate (PBLG), poly-L-lactic acid (PLA), polypeptide, and/or polyacetylene). The second material is within the chiral polymer. The first material and the second material are configured to provide an effective index of refraction value for the composite material of 1 or less. In some implementations, the effective index of refraction value for the composite material is negative. In some implementations, the effective index of refraction value for the composite material of 1 or less is at least in a wavelength of one of at least a visible spectrum, an infrared spectrum, a microwave spectrum, and/or an ultraviolet spectrum.

  9. Co-solvent Selection for Supercritical Fluid Extraction of Astaxanthin and Other Carotenoids from Penaeus monodon Waste

    National Research Council Canada - National Science Library

    Radzali, Shazana Azfar; Baharin, Badlishah Sham; Othman, Rashidi; Markom, Masturah; Rahman, Russly Abdul

    2014-01-01

    ...; the antioxidant activity of astaxanthin is 100 times higher than that of α-tocopherol. Penaeus monodon (tiger shrimp) is the largest commercially available shrimp species and its waste is a rich source of carotenoids such as astaxanthin and its esters...

  10. Protective Effect of Astaxanthin on Liver Fibrosis through Modulation of TGF-β1 Expression and Autophagy

    Directory of Open Access Journals (Sweden)

    Miao Shen

    2014-01-01

    Full Text Available Liver fibrosis is a common pathway leading to cirrhosis and a worldwide clinical issue. Astaxanthin is a red carotenoid pigment with antioxidant, anticancer, and anti-inflammatory properties. The aim of this study was to investigate the effect of astaxanthin on liver fibrosis and its potential protective mechanisms. Liver fibrosis was induced in a mouse model using CCL4 (intraperitoneal injection, three times a week for 8 weeks, and astaxanthin was administered everyday at three doses (20, 40, and 80 mg/kg. Pathological results indicated that astaxanthin significantly improved the pathological lesions of liver fibrosis. The levels of alanine aminotransferase aspartate aminotransferase and hydroxyproline were also significantly decreased by astaxanthin. The same results were confirmed in bile duct liagtion, (BDL model. In addition, astaxanthin inhibited hepatic stellate cells (HSCs activation and formation of extracellular matrix (ECM by decreasing the expression of NF-κB and TGF-β1 and maintaining the balance between MMP2 and TIMP1. In addition, astaxanthin reduced energy production in HSCs by downregulating the level of autophagy. These results were simultaneously confirmed in vivo and in vitro. In conclusion, our study showed that 80 mg/kg astaxanthin had a significant protective effect on liver fibrosis by suppressing multiple profibrogenic factors.

  11. Towards racemizable chiral organogelators

    Directory of Open Access Journals (Sweden)

    Jian Bin Lin

    2010-10-01

    Full Text Available A chiral organogelator has been synthesized that can be racemized and self-assembled in apolar solvents whilst at higher concentrations organogels are formed. Field emission scanning and transmission electron microscopy revealed the formation of bundle fibrils that are able to gelate the solvent. 1H NMR studies showed hydrogen-bond interactions between the peptide head groups of neighbouring organogelator molecules. The enantiomerically pure organogelator can be racemized by the base DBU (1,8-diazabicyclo[5.4.0]undec-7-ene as was evident from chiral high-performance liquid chromatography analysis.

  12. Towards racemizable chiral organogelators.

    Science.gov (United States)

    Lin, Jian Bin; Dasgupta, Debarshi; Cantekin, Seda; Schenning, Albertus P H J

    2010-10-06

    A chiral organogelator has been synthesized that can be racemized and self-assembled in apolar solvents whilst at higher concentrations organogels are formed. Field emission scanning and transmission electron microscopy revealed the formation of bundle fibrils that are able to gelate the solvent. ¹H NMR studies showed hydrogen-bond interactions between the peptide head groups of neighbouring organogelator molecules. The enantiomerically pure organogelator can be racemized by the base DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) as was evident from chiral high-performance liquid chromatography analysis.

  13. Production of the Marine Carotenoid Astaxanthin by Metabolically Engineered Corynebacterium glutamicum

    Directory of Open Access Journals (Sweden)

    Nadja A. Henke

    2016-06-01

    Full Text Available Astaxanthin, a red C40 carotenoid, is one of the most abundant marine carotenoids. It is currently used as a food and feed additive in a hundred-ton scale and is furthermore an attractive component for pharmaceutical and cosmetic applications with antioxidant activities. Corynebacterium glutamicum, which naturally synthesizes the yellow C50 carotenoid decaprenoxanthin, is an industrially relevant microorganism used in the million-ton amino acid production. In this work, engineering of a genome-reduced C. glutamicum with optimized precursor supply for astaxanthin production is described. This involved expression of heterologous genes encoding for lycopene cyclase CrtY, β-carotene ketolase CrtW, and hydroxylase CrtZ. For balanced expression of crtW and crtZ their translation initiation rates were varied in a systematic approach using different ribosome binding sites, spacing, and translational start codons. Furthermore, β-carotene ketolases and hydroxylases from different marine bacteria were tested with regard to efficient astaxanthin production in C. glutamicum. In shaking flasks, the C. glutamicum strains developed here overproduced astaxanthin with volumetric productivities up to 0.4 mg·L−1·h−1 which are competitive with current algae-based production. Since C. glutamicum can grow to high cell densities of up to 100 g cell dry weight (CDW·L−1, the recombinant strains developed here are a starting point for astaxanthin production by C. glutamicum.

  14. Milks pigmentation with astaxanthin and determination of colour stability during short period cold storage.

    Science.gov (United States)

    Mezquita, Pedro Cerezal; Huerta, Blanca E Barragán; Ramírez, Jenifer C Palma; Hinojosa, Claudia P Ortíz

    2015-03-01

    Astaxanthin has been used as a colorant and antioxidant with excellent results, its application and stability in food matrices to human consumption has been little studied. The aim of this work was the incorporation of astaxanthin oleoresin to milks with different fat content, simulating the red-orange color that can impart apricot fruit. For astaxanthin determination by HPLC, a methodology was implemented for its extraction from the food matrix, followed by saponification with KOH. Milk samples were stored (5 ± 2 °C) and stability of color and astaxanthin content were determined by colorimetry and high performance liquid chromatography each 24 h for a week. Pigment degradation followed first-order kinetic with a constant degradation of 0.259 day(-1) and 0.104 day(-1), in whole and semi-skimmed milk, respectively. Chromaticity coordinates L*, a*, b* for different types of milk showed a low dispersion of their values during the storage time, indicating high stability of astaxanthin within the matrix.

  15. Studies on the carotenoids in the muscle of salmon--V. Combination of astaxanthin and canthaxanthin with bovine serum albumin and egg albumin.

    Science.gov (United States)

    Henmi, H; Hata, M; Takeuchi, M

    1991-01-01

    1. Bovine serum albumin (BSA) and/or egg albumin were bound to astaxanthin or canthaxanthin easily and the spectroscopic characteristics of these complexes were similar to those of astaxanthin or canthaxanthin in the salmon muscle. 2. This result indicates that astaxanthin-BSA, -egg albumin, canthaxanthin-BSA and -egg albumin complexes were basically similar to astaxanthin-actomyosin and/or canthaxanthin-actomyosin complex in the salmon muscle. 3. The binding of salmon actomyosin to astaxanthin or canthaxanthin is not specific.

  16. Quantum interference distinguishes between constitutional isomers

    OpenAIRE

    Tüxen, Jens; Gerlich, Stefan; Eibenberger, Sandra; Arndt, Markus; Mayor, Marcel

    2014-01-01

    Matter waves, as introduced by de Broglie in 1923, are a fundamental quantum phenomenon, describing the delocalized center of mass motion of massive bodies and we show here their sensitivity to the molecular structure of constitutional isomers.

  17. Chiral self-discrimination in a M3L2 subphthalocyanine cage.

    Science.gov (United States)

    Claessens, Christian G; Torres, Tomás

    2002-12-11

    A tris(3-pyridyl)-substituted C3 symmetric subphthalocyanine (SubPc) was dimerized into a M3L2 cage in the presence of a stoichiometric amount of (en)Pd(NO3)2. NMR studies demonstrated the recognition event to be accompanied by chiral self-discrimination between the two enantiomers of the SubPc. Moreover, the specificity is such that only one of four possible isomers was detected in solution.

  18. Chirality in molecular collision dynamics

    Science.gov (United States)

    Lombardi, Andrea; Palazzetti, Federico

    2018-02-01

    Chirality is a phenomenon that permeates the natural world, with implications for atomic and molecular physics, for fundamental forces and for the mechanisms at the origin of the early evolution of life and biomolecular homochirality. The manifestations of chirality in chemistry and biochemistry are numerous, the striking ones being chiral recognition and asymmetric synthesis with important applications in molecular sciences and in industrial and pharmaceutical chemistry. Chiral discrimination phenomena, due to the existence of two enantiomeric forms, very well known in the case of interaction with light, but still nearly disregarded in molecular collision studies. Here we review some ideas and recent advances about the role of chirality in molecular collisions, designing and illustrating molecular beam experiments for the demonstration of chiral effects and suggesting a scenario for a stereo-directional origin of chiral selection.

  19. Chiral quark model

    Indian Academy of Sciences (India)

    ingful. In particular, it is interesting to analyze the hadronic tensor that parametrizes the deep inelastic scattering (DIS) and confront the model predictions with empirical data. This picture has led to interesting studies of hadron structure functions in bosonized chiral quark models. Here I will present the results of refs [5–7].

  20. Optimization of the IPP precursor supply for the production of lycopene, decaprenoxanthin and astaxanthin by Corynebacterium glutamicum

    Directory of Open Access Journals (Sweden)

    Sabine A.E. Heider

    2014-08-01

    Full Text Available The biotechnologically relevant bacterium C. glutamicum, currently used for the million ton-scale production of amino acids for the food and feed industries, is pigmented due to synthesis of the rare cyclic C50 carotenoid decaprenoxanthin and its glucosides. The precursors of carotenoid biosynthesis, isopenthenyl pyrophosphate (IPP and its isomer dimethylallyl pyrophosphate (DMAPP, are synthesized in this organism via the methylerythritol phosphate (MEP or non-mevalonate pathway. Terminal pathway engineering in recombinant C. glutamicum permitted the production of various nonnative C50 and C40 carotenoids. Here, the role of engineering isoprenoid precursor supply for lycopene production by C. glutamicum was characterized. Overexpression of dxs encoding the enzyme that catalyzes the first committed step of the MEP-pathway by chromosomal promoter exchange in a prophage-cured, genome-reduced C. glutamicum strain improved lycopene formation. Similarly, an increased IPP supply was achieved by chromosomal integration of two artificial operons comprising MEP pathway genes under the control of a constitutive promoter. Combined overexpression of dxs and the other six MEP pathways genes in C. glutamicum strain LYC3-MEP was not synergistic with respect to improving lycopene accumulation. Based on C. glutamicum strain LYC3-MEP astaxanthin could be produced in the mg per g cell dry weight range when the endogenous genes crtE, crtB and crtI for conversion of geranylgeranyl pyrophosphate to lycopene were coexpressed with the genes for lycopene cyclase and β-carotene hydroxylase from Pantoea ananatis and carotene C(4 oxygenase from Brevundimonas aurantiaca.

  1. Optimization of the IPP Precursor Supply for the Production of Lycopene, Decaprenoxanthin and Astaxanthin by Corynebacterium glutamicum

    Science.gov (United States)

    Heider, Sabine A. E.; Wolf, Natalie; Hofemeier, Arne; Peters-Wendisch, Petra; Wendisch, Volker F.

    2014-01-01

    The biotechnologically relevant bacterium Corynebacterium glutamicum, currently used for the million ton-scale production of amino acids for the food and feed industries, is pigmented due to synthesis of the rare cyclic C50 carotenoid decaprenoxanthin and its glucosides. The precursors of carotenoid biosynthesis, isopenthenyl pyrophosphate (IPP) and its isomer dimethylallyl pyrophosphate, are synthesized in this organism via the methylerythritol phosphate (MEP) or non-mevalonate pathway. Terminal pathway engineering in recombinant C. glutamicum permitted the production of various non-native C50 and C40 carotenoids. Here, the role of engineering isoprenoid precursor supply for lycopene production by C. glutamicum was characterized. Overexpression of dxs encoding the enzyme that catalyzes the first committed step of the MEP-pathway by chromosomal promoter exchange in a prophage-cured, genome-reduced C. glutamicum strain improved lycopene formation. Similarly, an increased IPP supply was achieved by chromosomal integration of two artificial operons comprising MEP pathway genes under the control of a constitutive promoter. Combined overexpression of dxs and the other six MEP pathways genes in C. glutamicum strain LYC3-MEP was not synergistic with respect to improving lycopene accumulation. Based on C. glutamicum strain LYC3-MEP, astaxanthin could be produced in the milligrams per gram cell dry weight range when the endogenous genes crtE, crtB, and crtI for conversion of geranylgeranyl pyrophosphate to lycopene were coexpressed with the genes for lycopene cyclase and β-carotene hydroxylase from Pantoea ananatis and carotene C(4) oxygenase from Brevundimonas aurantiaca. PMID:25191655

  2. Astaxanthin protecting membrane integrity against photosensitized oxidation through synergism with other carotenoids

    DEFF Research Database (Denmark)

    Du, Hui-Hui; Liang, Ran; Han, Rui-Min

    2015-01-01

    Incorporation of astaxanthin or zeaxanthin in giant unilamellar vesicles (GUVs) of phosphatidylcholine resulted in a longer lag phase than incorporation of β-carotene or lycopene for the onset of budding induced by chlorophyll a photosensitization and quantified by a dimensionless entropy parameter...... using optical microscopy and digital image heterogeneity analysis. The lowest initial rate of GUV budding after the lag phase was seen for GUVs with astaxanthin as the least reducing carotenoid, while the lowest final level of entropy appeared for those with lycopene or β-carotene as a more reducing...... carotenoid. The combination of astaxanthin and lycopene gave optimal protection against budding with respect to both a longer lag phase and lower final level of entropy by combining good electron acceptance and good electron donation. Quenching of singlet oxygen by carotenoids close to chlorophyll...

  3. Cytotoxic Induction and Photoacoustic Imaging of Breast Cancer Cells Using Astaxanthin-Reduced Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Subramaniyan Bharathiraja

    2016-04-01

    Full Text Available Astaxanthin, a kind of photosynthetic pigment, was employed for gold nanoparticle formation. Nanoparticles were characterized using Ulteraviolet-Visible (UV-Vis spectroscopy, transmission electron microscopy, and X-ray diffraction, and the possible presence of astaxanthin functional groups were analyzed by Fourier transform infrared spectroscopy (FTIR. The cytotoxic effect of synthesized nanoparticles was evaluated against MDA-MB-231 (human breast cancer cells using a tetrazolium-based assay, and synthesized nanoparticles exhibited dose-dependent toxicity. The morphology upon cell death was differentiated through fluorescent microscopy using different stains that predicted apoptosis. The synthesized nanoparticles were applied in ultrasound-coupled photoacoustic imaging to obtain good images of treated cells. Astaxanthin-reduced gold nanoparticle has the potential to act as a promising agent in the field of photo-based diagnosis and therapy.

  4. Production of astaxanthin rich feed supplement for animals from Phaffia rhodozyma yeast at low cost

    Science.gov (United States)

    Irtiza, Ayesha; Shatunova, Svetlana; Glukhareva, Tatiana; Kovaleva, Elena

    2017-09-01

    Dietary nutrients such as amino acids, vitamins, minerals and antioxidants can play a significant role in determining meat quality and also the growth rate of poultry or animal. Phaffia rhodozyma was grown on waste from brewery industry to produce astaxanthin rich feed supplements at a very low cost. Phaffia rhodozyma is yeast specie that has ability to produce carotenoids and approximately 80% of its total carotenoid content is astaxanthin, which is highly valuable carotenoid for food, feed and aquaculture industry. This study was carried out to test yeast extract of spent yeast from brewing industry waste (residual yeast) as potential nitrogen source for growth of Phaffia rhodozyma. Cultivation was carried out in liquid media prepared by yeast extracts and other components (glucose and peptone). Carotenoids from the biomass were released into biomass by suspending cells in DMSO for destruction of cells followed by extraction with petroleum ether. The extracted carotenoids were studied by spectrophotometry to identify and quantify astaxanthin and other carotenoids produced.

  5. Effects of Astaxanthin from Litopenaeus Vannamei on Carrageenan-Induced Edema and Pain Behavior in Mice.

    Science.gov (United States)

    Kuedo, Zulkiflee; Sangsuriyawong, Anantita; Klaypradit, Wanwimol; Tipmanee, Varomyalin; Chonpathompikunlert, Pennapa

    2016-03-19

    Carrageenan produces both inflammation and pain when injected in mouse paws via enhancement of reactive oxygen species formation. We have investigated an effect of astaxanthin extracted from Litopenaeus vannamei in carrageenan-induced mice paw edema and pain. The current study demonstrates interesting effects from astaxanthin treatment in mice: an inhibition of paw edema induced in hind paw, an increase in mechanical paw withdrawal threshold and thermal paw withdrawal latency, and a reduction in the amount of myeloperoxidase enzyme and lipid peroxidation products in the paw. Furthermore the effect was comparable to indomethacin, a standard treatment for inflammation symptoms. Due to adverse effects of indomethacin on cardiovascular and gastrointestinal systems, our study suggests promising prospect of astaxanthin extract as an anti-inflammatory alternative against carrageenan-induced paw edema and pain behavior.

  6. Hyperspectral imaging based on diffused laser light for prediction of astaxanthin coating concentration

    DEFF Research Database (Denmark)

    Ljungqvist, Martin Georg; Nielsen, Otto Højager Attermann; Frosch, Stina

    2014-01-01

    elastic net (EN). The ratio of standard error of prediction (RPD) is the ratio between the standard deviation of the reference values and the prediction error, and for both PLSR and EN both devices gave RPD values between 4 and 24, and with mean prediction error of 1.4–8.0 parts per million of astaxanthin......We present a study on predicting the concentration level of synthetic astaxanthin in fish feed pellet coating using multi- and hyperspectral image analysis. This was done in parallel using two different vision systems. A new instrument for hyperspectral imaging, the SuperK setup, using a super....... The spectral resolution made it possible to identify the most significant spectral regions for detection of astaxanthin. The results also imply that the presented methods can be used in general for quality inspection of various coating substances using similar coating methods....

  7. Improved Chiral Separation of Methamphetamine Enantiomers Using CSP-LC-MS-MS.

    Science.gov (United States)

    Ward, Lauren F; Enders, Jeffrey R; Bell, David S; Cramer, Hugh M; Wallace, Frank N; McIntire, Gregory L

    2016-05-01

    To determine the true enantiomeric composition of methamphetamine urine drug testing results, chiral separation of dextro (D) and levo (L) enantiomers is necessary. While enantiomeric separation of methamphetamine has traditionally been accomplished using gas chromatography-mass spectrometry (GC-MS), chiral separation of D- and L-methamphetamine by chiral stationary phase (CSP) liquid chromatography-mass spectrometry/mass spectrometry (LC-MS-MS) has proved more reliable. Chirally selective detection of methamphetamine by GC-MS is often performed using L-N-trifluoroacetyl-prolyl chloride (TPC). L-TPC, a chiral compound, is known to have impurities that can affect the chiral composition percentages of the methamphetamine sample, potentially leading to inaccurate patient results. The comparative analysis of the samples run by GC and LC methods showed preferential bias of the GC method for producing error rates, consistent with previous research, of 8-19%. The CSP-LC-MS-MS method produces percent deviation errors of methamphetamine isomer racemization is seen in samples when analyzed by GC-MS using L-TPC-derivatizing agent. This racemization is not seen when these samples are tested with CSP-LC-MS-MS. Thus, a more accurate method of enantiomeric analysis is provided by CSP-LC-MS-MS. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Engineering of a plasmid-free Escherichia coli strain for improved in vivo biosynthesis of astaxanthin

    Directory of Open Access Journals (Sweden)

    Steuer Kristin

    2011-04-01

    Full Text Available Abstract Background The xanthophyll astaxanthin is a high-value compound with applications in the nutraceutical, cosmetic, food, and animal feed industries. Besides chemical synthesis and extraction from naturally producing organisms like Haematococcus pluvialis, heterologous biosynthesis in non-carotenogenic microorganisms like Escherichia coli, is a promising alternative for sustainable production of natural astaxanthin. Recent achievements in the metabolic engineering of E. coli strains have led to a significant increase in the productivity of carotenoids like lycopene or β-carotene by increasing the metabolic flux towards the isoprenoid precursors. For the heterologous biosynthesis of astaxanthin in E. coli, however, the conversion of β-carotene to astaxanthin is obviously the most critical step towards an efficient biosynthesis of astaxanthin. Results Here we report the construction of the first plasmid-free E. coli strain that produces astaxanthin as the sole carotenoid compound with a yield of 1.4 mg/g cdw (E. coli BW-ASTA. This engineered E. coli strain harbors xanthophyll biosynthetic genes from Pantoea ananatis and Nostoc punctiforme as individual expression cassettes on the chromosome and is based on a β-carotene-producing strain (E. coli BW-CARO recently developed in our lab. E. coli BW-CARO has an enhanced biosynthesis of the isoprenoid precursor isopentenyl diphosphate (IPP and produces β-carotene in a concentration of 6.2 mg/g cdw. The expression of crtEBIY along with the β-carotene-ketolase gene crtW148 (NpF4798 and the β-carotene-hydroxylase gene (crtZ under controlled expression conditions in E. coli BW-ASTA directed the pathway exclusively towards the desired product astaxanthin (1.4 mg/g cdw. Conclusions By using the λ-Red recombineering technique, genes encoding for the astaxanthin biosynthesis pathway were stably integrated into the chromosome of E. coli. The expression levels of chromosomal integrated recombinant

  9. Multiple Mechanisms of Anti-Cancer Effects Exerted by Astaxanthin

    Directory of Open Access Journals (Sweden)

    Li Zhang

    2015-07-01

    Full Text Available Astaxanthin (ATX is a xanthophyll carotenoid which has been approved by the United States Food and Drug Administration (USFDA as food colorant in animal and fish feed. It is widely found in algae and aquatic animals and has powerful anti-oxidative activity. Previous studies have revealed that ATX, with its anti-oxidative property, is beneficial as a therapeutic agent for various diseases without any side effects or toxicity. In addition, ATX also shows preclinical anti-tumor efficacy both in vivo and in vitro in various cancer models. Several researches have deciphered that ATX exerts its anti-proliferative, anti-apoptosis and anti-invasion influence via different molecules and pathways including signal transducer and activator of transcription 3 (STAT3, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB and peroxisome proliferator-activated receptor gamma (PPARγ. Hence, ATX shows great promise as chemotherapeutic agents in cancer. Here, we review the rapidly advancing field of ATX in cancer therapy as well as some molecular targets of ATX.

  10. Multiple Mechanisms of Anti-Cancer Effects Exerted by Astaxanthin.

    Science.gov (United States)

    Zhang, Li; Wang, Handong

    2015-07-14

    Astaxanthin (ATX) is a xanthophyll carotenoid which has been approved by the United States Food and Drug Administration (USFDA) as food colorant in animal and fish feed. It is widely found in algae and aquatic animals and has powerful anti-oxidative activity. Previous studies have revealed that ATX, with its anti-oxidative property, is beneficial as a therapeutic agent for various diseases without any side effects or toxicity. In addition, ATX also shows preclinical anti-tumor efficacy both in vivo and in vitro in various cancer models. Several researches have deciphered that ATX exerts its anti-proliferative, anti-apoptosis and anti-invasion influence via different molecules and pathways including signal transducer and activator of transcription 3 (STAT3), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and peroxisome proliferator-activated receptor gamma (PPARγ). Hence, ATX shows great promise as chemotherapeutic agents in cancer. Here, we review the rapidly advancing field of ATX in cancer therapy as well as some molecular targets of ATX.

  11. Autoamplification of molecular chirality through the induction of supramolecular chirality.

    Science.gov (United States)

    van Dijken, Derk Jan; Beierle, John M; Stuart, Marc C A; Szymański, Wiktor; Browne, Wesley R; Feringa, Ben L

    2014-05-12

    The novel concept for the autoamplification of molecular chirality, wherein the amplification proceeds through the induction of supramolecular chirality, is presented. A solution of prochiral, ring-open diarylethenes is doped with a small amount of their chiral, ring-closed counterpart. The molecules co-assemble into helical fibers through hydrogen bonding and the handedness of the fibers is biased by the chiral, ring-closed diarylethene. Photochemical ring closure of the open diarylethene yields the ring-closed product, which is enriched in the template enantiomer. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Rapid Estimation of Astaxanthin and the Carotenoid-to-Chlorophyll Ratio in the Green Microalga Chromochloris zofingiensis Using Flow Cytometry.

    Science.gov (United States)

    Chen, Junhui; Wei, Dong; Pohnert, Georg

    2017-07-19

    The green microalga Chromochloris zofingiensis can accumulate significant amounts of valuable carotenoids, mainly natural astaxanthin, a product with applications in functional food, cosmetics, nutraceuticals, and with potential therapeutic value in cardiovascular and neurological diseases. To optimize the production of astaxanthin, it is essential to monitor the content of astaxanthin in algal cells during cultivation. The widely used HPLC (high-performance liquid chromatography) method for quantitative astaxanthin determination is time-consuming and laborious. In the present work, we present a method using flow cytometry (FCM) for in vivo determination of the astaxanthin content and the carotenoid-to-chlorophyll ratio (Car/Chl) in mixotrophic C. zofingiensis. The method is based on the assessment of fluorescent characteristics of cellular pigments. The mean fluorescence intensity (MFI) of living cells was determined by FCM to monitor pigment formation based on the correlation between MFI detected in particular channels (FL1: 533 ± 15 nm; FL2: 585 ± 20 nm; FL3: >670 nm) and pigment content in algal cells. Through correlation and regression analysis, a linear relationship was observed between MFI in FL2 (band-pass filter, emission at 585 nm in FCM) and astaxanthin content (in HPLC) and applied for predicting astaxanthin content. With similar procedures, the relationships between MFI in different channels and Car/Chl ratio in mixotrophic C. zofingiensis were also determined. Car/Chl ratios could be estimated by the ratios of MFI (FL1/FL3, FL2/FL3). FCM is thus a highly efficient and feasible method for rapid estimation of astaxanthin content in the green microalga C. zofingiensis. The rapid FCM method is complementary to the current HPLC method, especially for rapid evaluation and prediction of astaxanthin formation as it is required during the high-throughput culture in the laboratory and mass cultivation in industry.

  13. Chiral logarithms to five loops

    OpenAIRE

    Bissegger, Moritz; Fuhrer, Andreas

    2006-01-01

    We investigate two specific Green functions in the framework of chiral perturbation theory. We show that, using analyticity and unitarity, their leading logarithmic singularities can be evaluated in the chiral limit to any desired order in the chiral expansion, with a modest calculational cost. The claim is illustrated with an evaluation of the leading logarithm for the scalar two-point function to five-loop order.

  14. Chiral Biomarkers in Meteorites

    Science.gov (United States)

    Hoover, Richard B.

    2010-01-01

    The chirality of organic molecules with the asymmetric location of group radicals was discovered in 1848 by Louis Pasteur during his investigations of the rotation of the plane of polarization of light by crystals of sodium ammonium paratartrate. It is well established that the amino acids in proteins are exclusively Levorotary (L-aminos) and the sugars in DNA and RNA are Dextrorotary (D-sugars). This phenomenon of homochirality of biological polymers is a fundamental property of all life known on Earth. Furthermore, abiotic production mechanisms typically yield recemic mixtures (i.e. equal amounts of the two enantiomers). When amino acids were first detected in carbonaceous meteorites, it was concluded that they were racemates. This conclusion was taken as evidence that they were extraterrestrial and produced by abiologically. Subsequent studies by numerous researchers have revealed that many of the amino acids in carbonaceous meteorites exhibit a significant L-excess. The observed chirality is much greater than that produced by any currently known abiotic processes (e.g. Linearly polarized light from neutron stars; Circularly polarized ultraviolet light from faint stars; optically active quartz powders; inclusion polymerization in clay minerals; Vester-Ulbricht hypothesis of parity violations, etc.). This paper compares the measured chirality detected in the amino acids of carbonaceous meteorites with the effect of these diverse abiotic processes. IT is concluded that the levels observed are inconsistent with post-arrival biological contamination or with any of the currently known abiotic production mechanisms. However, they are consistent with ancient biological processes on the meteorite parent body. This paper will consider these chiral biomarkers in view of the detection of possible microfossils found in the Orgueil and Murchison carbonaceous meteorites. Energy dispersive x-ray spectroscopy (EDS) data obtained on these morphological biomarkers will be

  15. Chiral Dynamics 2006

    Science.gov (United States)

    Ahmed, Mohammad W.; Gao, Haiyan; Weller, Henry R.; Holstein, Barry

    2007-10-01

    pt. A. Plenary session. Opening remarks: experimental tests of chiral symmetry breaking / A. M. Bernstein. [Double pie symbols] scattering / H. Leutwyler. Chiral effective field theory in a [Triangle]-resonance region / V. Pascalutsa. Some recent developments in chiral perturbation theory / Ulf-G. Mei ner. Chiral extrapolation and nucleon structure from the lattice / R.D. Young. Recent results from HAPPEX / R. Michaels. Chiral symmetries and low energy searches for new physics / M.J. Ramsey-Musolf. Kaon physics: recent experimental progress / M. Moulson. Status of the Cabibbo angle / V. Cirigliano. Lattice QCD and nucleon spin structure / J.W. Negele. Spin sum rules and polarizabilities: results from Jefferson lab / J-P Chen. Compton scattering and nucleon polarisabilities / Judith A. McGovern. Virtual compton scattering at MIT-bates / R. Miskimen. Physics results from the BLAST detector at the BATES accelerator / R.P. Redwine. The [Pie sympbol]NN system, recent progress / C. Hanhart. Application of chiral nuclear forces to light nuclei / A. Nogga. New results on few-body experiments at low energy / Y. Nagai. Few-body lattice calculations / M.J. Savage. Research opportunities at the upgraded HI?S facility / H.R. Weller -- pt. B. Goldstone boson dynamics. Working group summary: Goldstone Boson dynamics / G. Colangelo and S. Giovannella. Recent results on radiative Kaon decays from NA48 and NA48/2 / S.G. López. Cusps in K-->3 [Pie symbol] decays / B. Kubis. Recent KTeV results on radiative Kaon decays / M.C. Ronquest. The [Double pie symbols] scattering amplitude / J.R. Peláez. Determination of the Regge parameters in the [Double pie symbols] scattering amplitude / I. Caprini. e+e- Hadronic cross section measurement at DA[symbol]NE with the KLOE detector / P. Beltrame. Measurement of the form factors of e+e- -->2([Pie symbol]+[Pie symbol]-), pp and the resonant parameters of the heavy charmonia at BES / H. Hu. Measurement of e+e- multihadronic cross section below 4

  16. Enantiomeric separation of tapentadol by capillary electrophoresis--study of chiral selectivity manipulation by various types of cyclodextrins.

    Science.gov (United States)

    Znaleziona, Joanna; Fejős, Ida; Ševčík, Juraj; Douša, Michal; Béni, Szabolcs; Maier, Vítězslav

    2015-02-01

    The chiral recognition of the centrally acting analgesic agent tapentadol and its isomers with various cyclodextrins (CDs) was studied by capillary electrophoresis, focusing on the migration order of four stereoisomers. In the case of non-charged hydroxypropylated CDs (2-hydroxypropyl-β-CD, 2-hydroxypropyl-γ-CD) the beta derivative was able to discriminate the S,R- and R,S-isomers in acidic background electrolyte, whereas the gamma allowed the separation of S,S- and R,R-tapentadol, respectively. Dual CD system containing both hosts was used to separate all of four isomers. Negatively charged sulfated-α-CD at 1.0% (w/v) concentration in 100mM sodium borate buffer (pH 9.5) was capable of separating the isomers with favorable enantiomer migration order and the optimized method was able to determine 0.15% of chiral impurities of tapentadol in the presence of the last migrating clinically important R,R-isomer. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Chiral algebras of class S

    Energy Technology Data Exchange (ETDEWEB)

    Beem, Christopher [Institute for Advanced Study,Einstein Dr., Princeton, NJ 08540 (United States); Peelaers, Wolfger; Rastelli, Leonardo [C.N. Yang Institute for Theoretical Physics, SUNY,Stony Brook, NY 11794-3840 (United States); Rees, Balt C. van [Theory Group, Physics Department, CERN,CH-1211 Geneva 23 (Switzerland)

    2015-05-05

    Four-dimensional N=2 superconformal field theories have families of protected correlation functions that possess the structure of two-dimensional chiral algebras. In this paper, we explore the chiral algebras that arise in this manner in the context of theories of class S. The class S duality web implies nontrivial associativity properties for the corresponding chiral algebras, the structure of which is best summarized in the language of generalized topological quantum field theory. We make a number of conjectures regarding the chiral algebras associated to various strongly coupled fixed points.

  18. Response Surface Methodology for Ultrasound-Assisted Extraction of Astaxanthin from Haematococcus pluvialis

    Directory of Open Access Journals (Sweden)

    Hong-Fu Wu

    2013-05-01

    Full Text Available Astaxanthin is a novel carotenoid nutraceutical occurring in many crustaceans and red yeasts. It has exhibited various biological activities including prevention or amelioration of cardiovascular disease, gastric ulcer, hypertension, and diabetic nephropathy. In this study, ultrasound-assisted extraction was developed for the effective extraction of astaxanthin from Haematococcus pluvialis. Some parameters such as extraction solvent, liquid-to-solid ratio, extraction temperature, and extraction time were optimized by single-factor experiment and response surface methodology. The optimal extraction conditions were 48.0% ethanol in ethyl acetate, the liquid-to-solid ratio was 20:1 (mL/g, and extraction for 16.0 min at 41.1 °C under ultrasound irradiation of 200 W. Under optimal conditions, the yield of astaxanthin was 27.58 ± 0.40 mg/g. The results obtained are beneficial for the full utilization of Haematococcus pluvialis, which also indicated that ultrasound-assisted extraction is a very useful method for extracting astaxanthin from marine life.

  19. Astaxanthin extraction from shrimp wastes and its stability in 2 model systems.

    Science.gov (United States)

    Franco-Zavaleta, M E; Jiménez-Pichardo, R; Tomasini-Campocosio, A; Guerrero-Legarreta, I

    2010-06-01

    The objective of this work was to study the stability of astaxanthin, obtained from shrimp wastes, and incorporated to 2 model systems: egg albumin protein solution and sunflower oil. Shrimp wastes were ensiled by a treatment with formic/acetic acids (4%-4% v/w wastes) and stored at 4 degrees C for 24 h. The pigment was extracted with organic solvents (petroleum ether:acetone:water, 15 : 75 : 10) and concentrated. The storage parameters studied were: illumination (light/dark), temperature (4/20 degrees C), atmosphere (air/air-free), and storage time (0, 1, 2, 3, 4, 5 wk). Results showed that total xantophylls and astaxanthin were more stable in sunflower oil than in the protein system. Total xantophylls showed more stability than astaxanthin, possibly due to the presence of other, more stable carotenoids quantified together with xantophylls. Astaxanthin concentration was significantly affected by storage time; its degradation followed a first-order reaction rate under all the studied conditions. This pigment was stable only for 17 d, even when stored in air-free flasks, under refrigeration, and in the dark.

  20. Gastric inflammatory markers and interleukins in patients with functional dyspepsia treated with astaxanthin

    DEFF Research Database (Denmark)

    Andersen, L.P.; Holck, Susanne; Kupcinskas, L.

    2007-01-01

    The chronic active inflammation caused by Helicobacter pylori is dominated by neutrophils, macrophages, lymphocytes and plasma cells. Several interleukins are involved in the inflammatory process. The aim of this study was to investigate the effect of astaxanthin on gastric inflammation in patien...

  1. Structural characterization of astaxanthin aggregates as revealed by analysis and simulation of optical spectra

    Science.gov (United States)

    Lu, Liping; Hu, Taoping; Xu, Zhigang

    2017-10-01

    Carotenoids can self-assemble in hydrated polar solvents to form J- or H-type aggregates, inducing dramatic changes in photophysical properties. Here, we measured absorption and emission spectra of astaxanthin in ethanol-water solution using ultraviolet-visible and fluorescence spectrometers. Two types of aggregates were distinguished in mixed solution at different water contents by absorption spectra. After addition of water, all probed samples immediately formed H-aggregates with maximum blue shift of 31 nm. In addition, J-aggregate was formed in 1:3 ethanol-water solution measured after an hour. Based on Frenkel exciton model, we calculated linear absorption and emission spectra of these aggregates to describe aggregate structures in solution. For astaxanthin, experimental results agreed well with the fitted spectra of H-aggregate models, which consisted of tightly packed stacks of individual molecules, including hexamers, trimers, and dimers. Transition moment of single astaxanthin in ethanol was obtained by Gaussian 09 program package to estimate the distance between molecules in aggregates. Intermolecular distance of astaxanthin aggregates ranges from 0.45 nm to 0.9 nm. Fluorescence analysis showed that between subbands, strong exciton coupling induced rapid relaxation of H-aggregates. This coupling generated larger Stokes shift than monomers and J-aggregates.

  2. Process design and economic evaluation of green extraction methods for recovery of astaxanthin from shrimp waste

    DEFF Research Database (Denmark)

    Razi Parjikolaei, Behnaz; Errico, Massimiliano; El-Houri, Rime Bahij

    2017-01-01

    Sunflower oil (SF) and its methyl ester as well as supercritical fluid (SC-CO2+ 5 wt% EtOH) have recently been shown as potential green solvents which could substitute traditional organic solvents. This study investigates the economic feasibility of using these green solvents to extract astaxanthin...

  3. Novel astaxanthin extraction from Haematococcus pluvialis using cell permeabilising ionic liquids

    NARCIS (Netherlands)

    Desai, R.K.; Streefland, M.; Wijffels, R.H.; Eppink, M.H.M.

    2016-01-01

    Haematococcus pluvialis (H. pluvialis) is a natural source of the food colorant astaxanthin. It is characterised by a thick resistant cell wall composed of a non-hydrolysable biopolymer, sporopollenin. High energy-consuming mechanical disruption is required to improve the extractability of

  4. Stability of astaxanthin in yogurt used to simulate apricot color, under refrigeration

    Directory of Open Access Journals (Sweden)

    Pedro Cerezal Mezquita

    2014-09-01

    Full Text Available The aim of this study was to incorporate astaxanthin to yogurts with different fat content to match apricot (Prunus armeniaca L. color. The samples containing astaxanthin were stored at 5 ± 3 °C, and color stability and astaxanthin content were determined by colorimetry and high performance liquid chromatography (HPLC, respectively. Yogurt samples were analyzed in triplicate every 24 hours for one week and subsequently every week for 3 more weeks There were no significant differences (p < 0.05 between astaxanthin concentration values at 0 and 28 days for both samples; therefore, it can be said that the fat content in the yogurt had not effect on the stability of pigment. The low dispersion of the data showed uniformity in the three chromaticity coordinates L*, a*, b* throughout the storage period for both types of yogurt. Values of ∆E ≥ 5.0 were not obtained at any time during storage, indicating high stability of the pigment.

  5. Elucidation of the pathway to astaxanthin in the flowers of Adonis aestivalis.

    Science.gov (United States)

    Cunningham, Francis X; Gantt, Elisabeth

    2011-08-01

    A few species in the genus Adonis are the only land plants known to produce the valuable red ketocarotenoid astaxanthin in abundance. Here, we ascertain the pathway that leads from the β-rings of β-carotene, a carotenoid ubiquitous in plants, to the 3-hydroxy-4-keto-β-rings of astaxanthin (3,3'-dihydroxy-β,β-carotene-4,4'-dione) in the blood-red flowers of Adonis aestivalis, an ornamental and medicinal plant commonly known as summer pheasant's eye. Two gene products were found to catalyze three distinct reactions, with the first and third reactions of the pathway catalyzed by the same enzyme. The pathway commences with the activation of the number 4 carbon of a β-ring in a reaction catalyzed by a carotenoid β-ring 4-dehydrogenase (CBFD), continues with the further dehydrogenation of this carbon to yield a carbonyl in a reaction catalyzed by a carotenoid 4-hydroxy-β-ring 4-dehydrogenase, and concludes with the addition of an hydroxyl group at the number 3 carbon in a reaction catalyzed by the erstwhile CBFD enzyme. The A. aestivalis pathway is both portable and robust, functioning efficiently in a simple bacterial host. Our elucidation of the pathway to astaxanthin in A. aestivalis provides enabling technology for development of a biological production process and reveals the evolutionary origin of this unusual plant pathway, one unrelated to and distinctly different from those used by bacteria, green algae, and fungi to synthesize astaxanthin.

  6. Response Surface Methodology for Ultrasound-Assisted Extraction of Astaxanthin from Haematococcus pluvialis

    Science.gov (United States)

    Zou, Tang-Bin; Jia, Qing; Li, Hua-Wen; Wang, Chang-Xiu; Wu, Hong-Fu

    2013-01-01

    Astaxanthin is a novel carotenoid nutraceutical occurring in many crustaceans and red yeasts. It has exhibited various biological activities including prevention or amelioration of cardiovascular disease, gastric ulcer, hypertension, and diabetic nephropathy. In this study, ultrasound-assisted extraction was developed for the effective extraction of astaxanthin from Haematococcus pluvialis. Some parameters such as extraction solvent, liquid-to-solid ratio, extraction temperature, and extraction time were optimized by single-factor experiment and response surface methodology. The optimal extraction conditions were 48.0% ethanol in ethyl acetate, the liquid-to-solid ratio was 20:1 (mL/g), and extraction for 16.0 min at 41.1 °C under ultrasound irradiation of 200 W. Under optimal conditions, the yield of astaxanthin was 27.58 ± 0.40 mg/g. The results obtained are beneficial for the full utilization of Haematococcus pluvialis, which also indicated that ultrasound-assisted extraction is a very useful method for extracting astaxanthin from marine life. PMID:23697948

  7. Combined fish oil and astaxanthin supplementation modulates rat lymphocyte function.

    Science.gov (United States)

    Otton, Rosemari; Marin, Douglas Popp; Bolin, Anaysa Paola; de Cássia Santos Macedo, Rita; Campoio, Thais Regina; Fineto, Claudio; Guerra, Beatriz Alves; Leite, José Roberto; Barros, Marcelo Paes; Mattei, Rita

    2012-09-01

    Higher intakes of n-3 polyunsaturated fatty acids that are abundant in marine fishes have been long described as a "good nutritional intervention" with increasing clinical benefits to cardiovascular health, inflammation, mental, and neurodegenerative diseases. The present study was designed to investigate the effect of daily fish oil (FO-10 mg EPA/kg body weight (BW) and 7 mg DHA/kg BW) intake by oral gavage associated with the antioxidant astaxanthin (ASTA-1 mg/kg BW) on the redox metabolism and the functional properties of lymphocytes from rat lymph nodes. This study was conducted by measurements of lymphocyte proliferation capacity, ROS production [superoxide (O₂(•-)) and hydrogen peroxide (H₂O₂)], nitric oxide (NO(•)) generation, intracellular calcium release, oxidative damage to lipids and proteins, activities of major antioxidant enzymes, GSH/GSSG content, and cytokines release. After 45 days of FO + ASTA supplementation, the proliferation capacity of activated T- and B-lymphocytes was significantly diminished followed by lower levels of O₂(•-), H₂O₂ and NO(•) production, and increased activities of total/SOD, GR and GPx, and calcium release in cytosol. ASTA was able to prevent oxidative modification in cell structures through the suppression of the oxidative stress condition imposed by FO. L: -selectin was increased by FO, and IL-1β was decreased only by ASTA supplementation. We can propose that association of ASTA with FO could be a good strategy to prevent oxidative stress induced by polyunsaturated fatty acids and also to potentiate immuno-modulatory effects of FO.

  8. Chiral nanophotonics chiral optical properties of plasmonic systems

    CERN Document Server

    Schäferling, Martin

    2017-01-01

    This book describes the physics behind the optical properties of plasmonic nanostructures focusing on chiral aspects. It explains in detail how the geometry determines chiral near-fields and how to tailor their shape and strength. Electromagnetic fields with strong optical chirality interact strongly with chiral molecules and, therefore, can be used for enhancing the sensitivity of chiroptical spectroscopy techniques. Besides a short review of the latest results in the field of plasmonically enhanced enantiomer discrimination, this book introduces the concept of chiral plasmonic near-field sources for enhanced chiroptical spectroscopy. The discussion of the fundamental properties of these light sources provides the theoretical basis for further optimizations and is of interest for researchers at the intersection of nano-optics, plasmonics and stereochemistry. .

  9. Effect of feeding methods on the astaxanthin production by Phaffia rhodozyma in fed-batch process

    Directory of Open Access Journals (Sweden)

    Danilo Gomes Moriel

    2005-05-01

    Full Text Available The effect of feeding methods on the production of astaxanthin by the yeast Phaffia rhodozyma ATCC 24202 was studied, using continuous and pulsed fed-batch processes and low cost materials as substrates (sugar cane juice and urea. In continuous fed-batch processes, a cellular astaxanthin concentration of 383.73 µg/g biomass was obtained. But in pulsed fed-batch processes a reduction in the cellular astaxanthin concentration (303.34 µg/g biomass was observed. Thus the continuous fed-batch processes could be an alternative to industrial production of astaxanthin, allowing an increase in the biomass productivity without losses on astaxanthin production by the yeast.O efeito da alimentação na produção de astaxantina pela levedura Phaffia rhodozyma ATCC 24202 foi estudado, utilizando processos descontínuo alimentado com alimentação contínua e intermitente, e matérias-primas de baixo custo como substratos (caldo de cana de açúcar e uréia. Em processos descontínuo alimentado com alimentação contínua, uma concentração celular de astaxantina de 383,73 µg/g biomassa foi obtida. Entretanto, em processos descontínuo alimentado com alimentação intermitente, uma redução na concentração celular de astaxantina (303,34 µg/g biomassa foi observada. Desta forma, processos descontínuo alimentado com alimentação contínua poderiam ser uma alternativa na produção industrial de astaxantina, permitindo um aumento na produtividade de biomassa sem perdas na produção de astaxantina pela levedura.

  10. Introduction of Branching Degrees of Octane Isomers.

    Science.gov (United States)

    Perdih, Anton

    2016-01-01

    The concept of branching degrees is introduced. In the case of octane isomers it is derived from the values of a set of their physicochemical properties, calculating for each isomer the average of the normalized values and these averages are defined as branching degrees of octane isomers. The sequence of these branching degrees of octane isomers does not differ much from the »regular« one defined earlier. 2,2-Dimethylhexane appears to be less branched than 3,4-dimethylhexane and 3-ethyl, 2-methylpentane, whereas 2,3,4-trimethylpentane appears to be less branched than 3-ethyl, 3-methylpentane. While the increasing number of branches gives rise to increasing branching degrees, the peripheral position of branches and the separation between branches decreases the value of the branching degree. The central position of branches increases it. A bigger branch increases it more than a smaller one. The quantification of these structural features and their correlations with few indices is given as well.

  11. Chiral Crystallization of Ethylenediamine Sulfate

    Science.gov (United States)

    Koby, Lawrence; Ningappa, Jyothi B.; Dakesssian, Maria; Cuccia, Louis A.

    2005-01-01

    The optimal conditions for the crystallization of achiral ethylenediamine sulfate into large chiral crystals that are ideal for polarimetry studies and observation using Polaroid sheets are presented. This experiment is an ideal undergraduate experiment, which clearly demonstrates the chiral crystallization of an achiral molecule.

  12. [Technological process of cell disruption for extracting astaxanthin from Phaffia rhodozyma by acid method under autoclave conditions].

    Science.gov (United States)

    Lu, Baoju; Xiao, Anfeng; Lil, Lijun; Ni, Hui; Cai, Huinong; Su, Wenjin

    2008-07-01

    Phaffia rhodozyma is one of the organisms for production of astaxanthin, and the key process for extracting intracellular astaxanthin is cell disruption. In this work, cell disruption for extracting astaxanthin from Phaffia rhodozyma was studied with autoclave method at low acid concentration. The optimum disrupting conditions were: autoclave pressure 0.1 MPa, 121 degrees C; hydrochloric acid concentration 0.5 mol/L; liquid to material ratio (V/W) 30 mL/g dry cell weight and disruption time 2 min. Under the optimum conditions, medium scale experiment showed that astaxanthin and total carotenoids recovery from Phaffia rhodozyma were (84.8 +/- 3.2)% and (93.3 +/- 2)%, respectively. This new method can lead to no poisonous residues and get high extraction yield, which have good prospects to be put into industrial production.

  13. Effect of dietary Astaxanthin sources supplementation on muscle pigmentation and lipid peroxidation in rainbow trout (Oncorhynchus mykiss

    Directory of Open Access Journals (Sweden)

    Marco Saroglia

    2010-01-01

    Full Text Available Astaxanthin is one of the major carotenoids in aquatic animals including salmonid fishes and is the preferred pigments added to salmon feed. It’s also a powerful antioxidant compared to other carotenoids and that may confer numerous health benefits. The aim of the present experi- ment was to investigate the effect of Astaxanthin deposition on the lipids peroxidation by studying the Malondialdeide (MDA level in muscle of rainbow trout (Oncorhynchus mykiss. The Astaxanthin concentrations in fish fed with a commercial sources as Lucantin®Pink (BASF Ludwigshafen, Ger- many reached values to 5.76±0.18x10-3 mg/g after 50 days feeding, while the MDA concentration de- creased from 1.56x103 to 0.45x103 ng/g. The correlation between MDA and Astaxanthin concentrations decreased linearly and confirmed the antioxidant properties of the pigment by reducing the lipids peroxidation.

  14. Two-chiral component microemulsion EKC - chiral surfactant and chiral oil. Part 2: diethyl tartrate.

    Science.gov (United States)

    Kahle, Kimberly A; Foley, Joe P

    2007-08-01

    In this second study on dual-chirality microemulsions containing a chiral surfactant and a chiral oil, a less hydrophobic and lower interfacial tension chiral oil, diethyl tartrate, is employed (Part 1, Foley, J. P. et al.., Electrophoresis, DOI: 10.1002/elps.200600551). Six stereochemical combinations of dodecoxycarbonylvaline (DDCV: R, S, or racemic, 2.00% w/v), racemic 2-hexanol (1.65% v/v), and diethyl tartrate (D, L, or racemic, 0.88% v/v) were examined as pseudostationary phases (PSPs) for the enantioseparation of six chiral pharmaceutical compounds: pseudoephedrine, ephedrine, N-methyl ephedrine, metoprolol, synephrine, and atenolol. Average efficiencies increased with the addition of a chiral oil to R-DDCV PSP formulations. Modest improvements in resolution and enantioselectivity (alpha(enant)) were achieved with two-chiral-component systems over the one-chiral-component microemulsion. Slight enantioselective synergies were confirmed using a thermodynamic model. Results obtained in this study are compared to those obtained in Part 1 as well as those obtained with chiral MEEKC using an achiral, low-interfacial-tension oil (ethyl acetate). Dual-chirality microemulsions with the more hydrophobic oil dibutyl tartrate yielded, relative to diethyl tartrate, higher efficiencies (100,000-134,000 vs. 80,800-94,300), but lower resolution (1.64-1.91 vs. 2.08-2.21) due to lower enantioselectivities (1.060-1.067 vs. 1.078-1.081). Atenolol enantiomers could not be separated with the dibutyl tartrate-based microemulsions but were partially resolved using diethyl tartrate microemulsions. A comparable single-chirality microemulsion based on the achiral oil ethyl acetate yielded, relative to diethyl tartrate, lower efficiency (78 300 vs. 91 600), higher resolution (1.99 vs. 1.83), and similar enantioselectivities.

  15. Quark structure of chiral solitons

    Energy Technology Data Exchange (ETDEWEB)

    Dmitri Diakonov

    2004-05-01

    There is a prejudice that the chiral soliton model of baryons is something orthogonal to the good old constituent quark models. In fact, it is the opposite: the spontaneous chiral symmetry breaking in strong interactions explains the appearance of massive constituent quarks of small size thus justifying the constituent quark models, in the first place. Chiral symmetry ensures that constituent quarks interact very strongly with the pseudoscalar fields. The ''chiral soliton'' is another word for the chiral field binding constituent quarks. We show how the old SU(6) quark wave functions follow from the ''soliton'', however, with computable relativistic corrections and additional quark-antiquark pairs. We also find the 5-quark wave function of the exotic baryon Theta+.

  16. Applications Of Chiral Perturbation Theory

    CERN Document Server

    Mohta, V

    2005-01-01

    Effective field theory techniques are used to describe the spectrum and interactions of hadrons. The mathematics of classical field theory and perturbative quantum field theory are reviewed. The physics of effective field theory and, in particular, of chiral perturbation theory and heavy baryon chiral perturbation theory are also reviewed. The geometry underlying heavy baryon chiral perturbation theory is described in detail. Results by Coleman et. al. in the physics literature are stated precisely and proven. A chiral perturbation theory is developed for a multiplet containing the recently- observed exotic baryons. A small coupling expansion is identified that allows the calculation of self-energy corrections to the exotic baryon masses. Opportunities in lattice calculations are discussed. Chiral perturbation theory is used to study the possibility of two multiplets of exotic baryons mixed by quark masses. A new symmetry constraint on reduced partial widths is identified. Predictions in the literature based ...

  17. Chiral Nuclear Dynamics II

    CERN Document Server

    Rho, Mannque

    2008-01-01

    This is the sequel to the first volume to treat in one effective field theory framework the physics of strongly interacting matter under extreme conditions. This is vital for understanding the high temperature phenomena taking place in relativistic heavy ion collisions and in the early Universe, as well as the high-density matter predicted to be present in compact stars. The underlying thesis is that what governs hadronic properties in a heat bath and/or a dense medium is hidden local symmetry which emerges from chiral dynamics of light quark systems and from the duality between QCD in 4D and

  18. Extraction of astaxanthin from giant tiger (Panaeus monodon) shrimp waste using palm oil: studies of extraction kinetics and thermodynamic.

    Science.gov (United States)

    Handayani, Akdes Dewi; Sutrisno; Indraswati, Nani; Ismadji, Suryadi

    2008-07-01

    Study of extraction of astaxanthin from giant tiger (Panaeus monodon) shrimp waste using palm oil was conducted to determine the extraction kinetics and thermodynamic parameters. Two extraction models were proposed: mass transfer kinetic model and reaction kinetic model. It was found that both of mass transfer and reaction kinetic control the extraction of astaxanthin from shrimp waste using palm oil. The thermodynamic parameters of extraction were also obtained in this study.

  19. Astaxanthin enhances pemetrexed-induced cytotoxicity by downregulation of thymidylate synthase expression in human lung cancer cells.

    Science.gov (United States)

    Liao, Kai-Sheng; Wei, Chia-Li; Chen, Jyh-Cheng; Zheng, Hao-Yu; Chen, Wen-Ching; Wu, Chia-Hung; Wang, Tai-Jing; Peng, Yi-Shuan; Chang, Po-Yuan; Lin, Yun-Wei

    2016-11-01

    Pemetrexed, a multitargeted antifolate agent, has demonstrated clinical activity in non-small cell lung cancer (NSCLC) cells. Increased expression of thymidylate synthase (TS) is thought to be associated with resistance to pemetrexed. Astaxanthin exhibits a wide range of beneficial effects including anti-cancer and anti-inflammatory properties. In this study, we showed that down-regulating of TS expression in two NSCLC cell lines, human lung adenocarcinoma H1650 and squamous cell carcinoma H1703 cells, with astaxanthin were associated with decreased MKK1/2-ERK1/2 activity. Enforced expression of constitutively active MKK1 (MKK1-CA) vector significantly rescued the decreased TS mRNA and protein levels in astaxanthin-treated NSCLC cells. Combined treatment with a MKK1/2 inhibitor (U0126 or PD98059) further decreased the TS expression in astaxanthin-exposed NSCLC cells. Knockdown of TS using small interfering RNA (siRNA) or inhibiting ERK1/2 activity enhanced the cytotoxicity and cell growth inhibition of astaxanthin. Combination of pemetrexed and astaxanthin resulted in synergistic enhancing cytotoxicity and cell growth inhibition in NSCLC cells, accompanied with reduced activation of phospho-MKK1/2, phopho-ERK1/2, and TS expression. Overexpression of MKK1/2-CA reversed the astaxanthin and pemetrexed-induced synergistic cytotoxicity. Our findings suggested that the down-regulation of MKK1/2-ERK1/2-mediated TS expression by astaxanthin is an important regulator of enhancing the pemetrexed-induced cytotoxicity in NSCLC cells. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Determination of fucoxanthin isomers in microalgae (Isochrysis sp.) by high-performance liquid chromatography coupled with diode-array detector multistage mass spectrometry coupled with positive electrospray ionization.

    Science.gov (United States)

    Crupi, Pasquale; Toci, Aline Theodore; Mangini, Silvio; Wrubl, Federico; Rodolfi, Liliana; Tredici, Mario R; Coletta, Antonio; Antonacci, Donato

    2013-05-15

    Due to their health benefits, there is growing interest in the production and use of carotenoids from natural sources, e.g. microalgae. To date, only Haematococcus pluvialis and Dunaliella, that accumulate, respectively, astaxanthin and β-carotene in large quantities, are grown commercially. However, interest is also being focused on other xanthophylls, such as (all-E)-fucoxanthin characterized by anti-obesity and anti-carcinogenic effects. In this regard, rigorous chemical and analytical techniques following preparative isolation of components are needed to unequivocally identify individual carotenoids in microalgae. The carotenoid profile of Isochrysis sp. biomass, produced in closed photobioreactors, was determined by reversed-phase C30 (RP-30) high-performance liquid chromatography coupled with diode-array detector mass spectrometry using positive electrospray ionization (HPLC/DAD-MS/ESI(+) ) analysis. Additionally, multistage mass spectrometry (MS(n) ) analyses, together with fine structures of the UV-vis spectra, were used to differentiate structural and geometrical isomers. This technique allowed the simultaneous determination of geometrical, isomers of fucoxanthin (all-E-fucoxanthin, 13Z-, 13'Z- and 9'Z-fucoxanthin), diatoxanthin and 5,8-epoxydiadinoxanthin diasteroisomers (R/S). The analyzed extracts contained fucoxanthin isomers as the major carotenoids and, in particular, (all-E)-fucoxanthin was the main geometrical isomer (~85%) found at a concentration of 17 mg/g of the lyophilized biomass. Considering the high content of fucoxanthin in Isochrysis sp. biomass, the microalga could be proposed as a source of this compound for nutraceutical and pharmaceutical applications. Copyright © 2013 John Wiley & Sons, Ltd.

  1. Simultaneous production of triacylglycerol and high-value carotenoids by the astaxanthin-producing oleaginous green microalga Chlorella zofingiensis.

    Science.gov (United States)

    Liu, Jin; Mao, Xuemei; Zhou, Wenguang; Guarnieri, Michael T

    2016-08-01

    The production of lipids and astaxanthin, a high-value carotenoid, by Chlorella zofingiensis was investigated under different culture conditions. Comparative analysis revealed a good correlation between triacylglycerol (TAG) and astaxanthin accumulation in C. zofingiensis. Stress conditions promoted cell size and weight and induced the accumulation of neutral lipids, especially TAG and astaxanthin, with a concomitant decrease in membrane lipids. The highest contents of TAG and astaxanthin achieved were 387 and 4.89mgg(-1) dry weight, respectively. A semi-continuous culture strategy was developed to optimize the TAG and astaxanthin productivities, which reached 297 and 3.3mgL(-1)day(-1), respectively. Additionally, astaxanthin accumulation was enhanced by inhibiting de novo fatty acid biosynthesis. In summary, our study represents a pioneering work of utilizing Chlorella for the integrated production of lipids and high-value products and C. zofingiensis has great potential to be a promising production strain and serve as an emerging oleaginous model alga. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Three-dimensional ultrastructural study of oil and astaxanthin accumulation during encystment in the green alga Haematococcus pluvialis.

    Directory of Open Access Journals (Sweden)

    Marina Wayama

    Full Text Available Haematococcus pluvialis is a freshwater species of green algae and is well known for its accumulation of the strong antioxidant astaxanthin, which is used in aquaculture, various pharmaceuticals, and cosmetics. High levels of astaxanthin are present in cysts, which rapidly accumulate when the environmental conditions become unfavorable for normal cell growth. It is not understood, however, how accumulation of high levels of astaxanthin, which is soluble in oil, becomes possible during encystment. Here, we performed ultrastructural 3D reconstruction based on over 350 serial sections per cell to visualize the dynamics of astaxanthin accumulation and subcellular changes during the encystment of H. pluvialis. This study showcases the marked changes in subcellular elements, such as chloroplast degeneration, in the transition from green coccoid cells to red cyst cells during encystment. In green coccoid cells, chloroplasts accounted for 41.7% of the total cell volume, whereas the relative volume of astaxanthin was very low (0.2%. In contrast, oil droplets containing astaxanthin predominated in cyst cells (52.2%, in which the total chloroplast volume was markedly decreased (9.7%. Volumetric observations also demonstrated that the relative volumes of the cell wall, starch grains, pyrenoids, mitochondria, the Golgi apparatus, and the nucleus in a cyst cell are smaller than those in green coccid cells. Our data indicated that chloroplasts are degraded, resulting in a net-like morphology, but do not completely disappear, even at the red cyst stage.

  3. Astaxanthin degradation and lipid oxidation of Pacific white shrimp oil: kinetics study and stability as affected by storage conditions

    Directory of Open Access Journals (Sweden)

    Sirima Takeungwongtrakul

    2016-02-01

    Full Text Available Abstract The kinetics of astaxanthin degradation and lipid oxidation in shrimp oil from hepatopancreas of Pacific white shrimp (Litopenaeus vannamei as affected by storage temperature were studied. When shrimp oil was incubated at different temperatures (4, 30, 45 and 60 °C for 16 h, the rate constants (k of astaxanthin degradation and lipid oxidation in shrimp oil increased with increasing temperatures (p < 0.05. Thus, astaxanthin degradation and lipid oxidation in shrimp oil were augmented at high temperature. When shrimp oils with different storage conditions (illumination, oxygen availability and temperature were stored for up to 40 days, astaxanthin contents in all samples decreased throughout storage (p < 0.05. All factors were able to enhance astaxanthin degradation during 40 days of storage. With increasing storage time, the progressive formation of primary and secondary oxidation products were found in all samples as evidenced by the increases in both peroxide values (PV and thiobarbituric acid reactive substances (TBARS (p < 0.05. Light, air and temperatures therefore had the marked effect on astaxanthin degradation and lipid oxidation in shrimp oils during the extended storage.

  4. Chiral quantum optics.

    Science.gov (United States)

    Lodahl, Peter; Mahmoodian, Sahand; Stobbe, Søren; Rauschenbeutel, Arno; Schneeweiss, Philipp; Volz, Jürgen; Pichler, Hannes; Zoller, Peter

    2017-01-25

    Advanced photonic nanostructures are currently revolutionizing the optics and photonics that underpin applications ranging from light technology to quantum-information processing. The strong light confinement in these structures can lock the local polarization of the light to its propagation direction, leading to propagation-direction-dependent emission, scattering and absorption of photons by quantum emitters. The possibility of such a propagation-direction-dependent, or chiral, light-matter interaction is not accounted for in standard quantum optics and its recent discovery brought about the research field of chiral quantum optics. The latter offers fundamentally new functionalities and applications: it enables the assembly of non-reciprocal single-photon devices that can be operated in a quantum superposition of two or more of their operational states and the realization of deterministic spin-photon interfaces. Moreover, engineered directional photonic reservoirs could lead to the development of complex quantum networks that, for example, could simulate novel classes of quantum many-body systems.

  5. Chiral imbalance in QCD

    Directory of Open Access Journals (Sweden)

    Andrianov Alexander

    2017-01-01

    Full Text Available The chiral imbalance (ChI is given by a difference between the numbers of RH and LH quarks which may occur in the fireball after heavy ion collision. To characterize it adiabatically a quark chiral (axial chemical potential must be introduced taking into account emergence of a ChI in such a phase. In this report the phenomenology of formation of Local spatial Parity Breaking (LPB in the hot and dense baryon matter is discussed and its simulation within a number of QCD-inspired models is outlined. The appearance of new states in the spectra of scalar, pseudoscalar and vector particles in such a matter is elucidated. In particular, from the effective vector meson theory in the presence of Chern-Simons interaction it is demonstrated that the spectrum of massive vector mesons splits into three polarization components with different effective masses. The asymmetry in production of longitudinally and transversely polarized states of ρ and ω mesons for various values of the dilepton invariant mass can serve as a characteristic indication of the LPB in PHENIX, STAR and ALICE experiments.

  6. Chiral imbalance in QCD

    Science.gov (United States)

    Andrianov, Alexander; Andrianov, Vladimir; Espriu, Domenec

    2017-03-01

    The chiral imbalance (ChI) is given by a difference between the numbers of RH and LH quarks which may occur in the fireball after heavy ion collision. To characterize it adiabatically a quark chiral (axial) chemical potential must be introduced taking into account emergence of a ChI in such a phase. In this report the phenomenology of formation of Local spatial Parity Breaking (LPB) in the hot and dense baryon matter is discussed and its simulation within a number of QCD-inspired models is outlined. The appearance of new states in the spectra of scalar, pseudoscalar and vector particles in such a matter is elucidated. In particular, from the effective vector meson theory in the presence of Chern-Simons interaction it is demonstrated that the spectrum of massive vector mesons splits into three polarization components with different effective masses. The asymmetry in production of longitudinally and transversely polarized states of ρ and ω mesons for various values of the dilepton invariant mass can serve as a characteristic indication of the LPB in PHENIX, STAR and ALICE experiments.

  7. Chiral Tagging of Verbenone with 3-BUTYN-2-OL for Establishing Absolute Configuration and Determining Enantiomeric Excess

    Science.gov (United States)

    Evangelisti, Luca; Mayer, Kevin J.; Holdren, Martin S.; Smart, Taylor; West, Channing; Pate, Brooks; Sedo, Galen; Marshall, Frank E.; Grubbs, G. S., II

    2017-06-01

    Chiral analysis of a commercial sample of (1S)-(-)-verbenone has been performed using the chiral tag approach. The chirped-pulse Fourier transform microwave spectrum of the verbenone-butynol complex is measured in the 2-8 GHz frequency range. Verbenone is placed in a nozzle reservoir heated to 333K (about 1 Torr vapor pressure). The complex is formed by using a carrier gas of neon with approximately 0.1% butynol. The expansion pressure is about 2 atm. A measurement using racemic butynol is performed to identify isomers of both diastereomer complexes. Quantum chemistry calculations using the B3LYP-D3BJ method with the def2TZVP basis set provided estimated spectroscopic constants for the homochiral and heterochiral complexes. This analysis included 8 isomers for each diastereomer. Four rotational spectra are identified for isomers of the homochiral complex and correspond to the four lowest energy isomers from the theoretical study. Three heterochiral complexes are identified and also correspond to the lowest energy isomers from theory. Subsequent measurements were made with enantiopure tag (both (R)-(+)-3-buty-2-nol and (S)-(-)-3-butyn-2-ol) to establish the absolute configuration of verbenone. The sensitivity of the measurement was sufficient to perform ^{13}C-isotopologue analysis of three of the homochiral complexes and two of the heterochiral complexes. These results provide definitive structures of verbenone with correct stereochemistry. The commercial sample has relatively low enantiomeric excess with the certificate of analysis reporting an EE of 53.6%. Using the intensities of assigned transitions of the chiral tag complexes, the enantiomeric excess was determined from the broadband rotational spectrum through the ratio of the intensities of pairs of transitions. A total of 2617 pairs of transitions were analyzed. The average EE was found to be 53.6% with a standard deviation of 2%.

  8. Chiral quantum dot based materials

    Science.gov (United States)

    Govan, Joseph; Loudon, Alexander; Baranov, Alexander V.; Fedorov, Anatoly V.; Gun'ko, Yurii

    2014-05-01

    Recently, the use of stereospecific chiral stabilising molecules has also opened another avenue of interest in the area of quantum dot (QD) research. The main goal of our research is to develop new types of technologically important quantum dot materials containing chiral defects, study their properties and explore their applications. The utilisation of chiral penicillamine stabilisers allowed the preparation of new water soluble white emitting CdS quantum nanostructures which demonstrated circular dichroism in the band-edge region of the spectrum. It was also demonstrated that all three types of QDs (D-, L-, and Rac penicillamine stabilised) show very broad emission bands between 400 and 700 nm due to defects or trap states on the surfaces of the nanocrystals. In this work the chiral CdS based quantum nanostructures have also been doped by copper metal ions and new chiral penicilamine stabilized CuS nanoparticles have been prepared and investigated. It was found that copper doping had a strong effect at low levels in the synthesis of chiral CdS nanostructures. We expect that this research will open new horizons in the chemistry of chiral nanomaterials and their application in biotechnology, sensing and asymmetric synthesis.

  9. Chiral effects in adrenocorticolytic action of o,p'-DDD (mitotane) in human adrenal cells.

    Science.gov (United States)

    Asp, V; Cantillana, T; Bergman, A; Brandt, I

    2010-03-01

    Adrenocortical carcinoma (ACC) is a rare malignant disease with poor prognosis. The main pharmacological choice, o,p'-DDD (mitotane), produces severe adverse effects. Since o,p'-DDD is a chiral molecule and stereoisomers frequently possess different pharmacokinetic and/or pharmacodynamic properties, we isolated the two o,p'-DDD enantiomers, (R)-(+)-o,p'-DDD and (S)-(-)-o,p'-DDD, and determined their absolute structures. The effects of each enantiomer on cell viability and on cortisol and dehydroepiandrosterone (DHEA) secretion in the human adrenocortical cell line H295R were assessed. We also assayed the o,p'-DDD racemate and the m,p'- and p,p'-isomers. The results show small but statistically significant differences in activity of the o,p'-DDD enantiomers for all parameters tested. The three DDD isomers were equally potent in decreasing cell viability, but p,p'-DDD affected hormone secretion slightly less than the o,p'- and m,p'-isomers. The small chiral differences in direct effects on target cells alone do not warrant single enantiomer administration, but might reach importance in conjunction with possible stereochemical effects on pharmacokinetic processes in vivo.

  10. Stereoselective Degradation and Molecular Ecological Mechanism of Chiral Pesticides Beta-Cypermethrin in Soils with Different pH Values.

    Science.gov (United States)

    Yang, Zhong-Hua; Ji, Guo-Dong

    2015-12-15

    For decades, pesticides have been widely used for agricultural activities around the world, and the environmental problems caused by these compounds have raised widespread concern. However, the different enantioselective behaviors of chiral pesticide enantiomers are often ignored. Here, the selective degradation patterns and mechanisms of chiral pesticide enantiomers were successfully investigated for the first time in the soils of three cultivation areas with different pH values. Beta-cypermethrin was chosen as the target analyte. We found that the degradation rates of the four isomers of beta-cypermethrin were different. We used stepwise regression equations between degradation rates and functional genes to quantitatively study their relationships. Quantitative response analysis revealed that different isomers have different equations even under identical conditions. The results of path analysis showed that a single functional gene can make different direct and indirect contributions to the degradation of different isomers. Finally, the high-throughput technology was used to analysis the genome of the three tested soils and then compared the main microbial communities in them. We have successfully devised a method to investigate the molecular biological mechanisms of the selective degradation behavior of chiral compounds, thus enabling us to better understand these mechanisms.

  11. Quarks, baryons and chiral symmetry

    CERN Document Server

    Hosaka, Atsushi

    2001-01-01

    This book describes baryon models constructed from quarks, mesons and chiral symmetry. The role of chiral symmetry and of quark model structure with SU(6) spin-flavor symmetry are discussed in detail, starting from a pedagogic introduction. Emphasis is placed on symmetry aspects of the theories. As an application, the chiral bag model is studied for nucleon structure, where important methods of theoretical physics, mostly related to the semiclassical approach for a system of strong interactions, are demonstrated. The text is more practical than formal; tools and ideas are explained in detail w

  12. Solvent selectivity studies using isomers of polystyrene

    Energy Technology Data Exchange (ETDEWEB)

    Men, L.C.; Na, H.; Rogers, L.B.

    1984-01-01

    The order of elution of isomeric trimers of polystyrene has been found to be independent of the dominant solvent-solute interaction as indicated by the location of the solvent in a Snyder triangle. The pure solvents were nitromethane, propylene carbonate, N-methylformamide, acetonitrile, the mixtures were trifluoroethanol with chloroform, methylene chloride and trichlorotrifluoroethane and also one of 2-methoxyethanol with water. Likewise, mixtures of acetonitrile with solvents near each of the corners of that triangle (chloroform, methylene chloride, and trifluoroethanol did not change the order of isomer elution). Substitution of trifluoroethanol for ethanol in mixtures with chloroform, methylene chloride, or trichlorotrifluoroethane led to improved isomer fractionations. 3 references, 5 figures, 2 tables.

  13. Novel peptide isomer strategy for stable inhibition of catecholamine release: Application to hypertension

    Science.gov (United States)

    Biswas, Nilima; Gayen, Jiaur; Mahata, Manjula; Su, Ying; Mahata, Sushil K.; O’Connor, Daniel T.

    2012-01-01

    Although hypertension remains the most potent and widespread cardiovascular risk factor, its pharmacological treatment has achieved only limited success. The chromogranin A derived fragment catestatin inhibits catecholamine release by acting as an endogenous nicotinic cholinergic antagonist, and can “rescue” hypertension in the setting of CHGA targeted ablation. Here we undertook novel peptide chemistry to synthesize isomers of catestatin: normal/wild-type (W-T) as well as a retro-inverso (R-I) version, with not only inversion of chirality (L→D amino acids) but also reversal of sequence (carboxyl→amino). The R-I peptide was entirely resistant to proteolytic digestion, and displayed enhanced potency as well as preserved specificity of action towards nicotinic cholinergic events: catecholamine secretion, agonist desensitization, secretory protein transcription, and cationic signal transduction. Structural modeling suggested similar side chain orientations of the W-T and R-I isomers, while CD spectroscopy documented inversion of chirality. In vivo, the R-I peptide “rescued” hypertension in two mouse models of the human trait: monogenic Chga targeted ablation, with prolonged efficacy of the R-I version; and a polygenic model, with magnified efficacy of the R-I version. These results may have general implications for generation of metabolically stable mimics of biologically active peptides for cardiovascular pathways. The findings also point the way toward a potential new class of drug therapeutics for an important risk trait, and more generally open the door to broader applications of the retro-inverso strategy in other pathways involved in cardiovascular biology, with the potential for synthesis of diagnostic and therapeutic probes for both physiology and disease. PMID:23129699

  14. Chiral higher spin gravity

    Science.gov (United States)

    Krishnan, Chethan; Raju, Avinash

    2017-06-01

    We construct a candidate for the most general chiral higher spin theory with AdS3 boundary conditions. In the Chern-Simons language, on the left it has the Drinfeld-Sokolov reduced form, but on the right all charges and chemical potentials are turned on. Altogether (for the spin-3 case) these are 19 functions. Despite this, we show that the resulting metric has the form of the "most general" AdS3 boundary conditions discussed by Grumiller and Riegler. The asymptotic symmetry algebra is a product of a W3 algebra on the left and an affine s l (3 )k current algebra on the right, as desired. The metric and higher spin fields depend on all the 19 functions. We compare our work with previous results in the literature.

  15. Amino Acids and Chirality

    Science.gov (United States)

    Cook, Jamie E.

    2012-01-01

    Amino acids are among the most heavily studied organic compound class in carbonaceous chondrites. The abundance, distributions, enantiomeric compositions, and stable isotopic ratios of amino acids have been determined in carbonaceous chondrites fi'om a range of classes and petrographic types, with interesting correlations observed between these properties and the class and typc of the chondritcs. In particular, isomeric distributions appear to correlate with parent bodies (chondrite class). In addition, certain chiral amino acids are found in enantiomeric excess in some chondrites. The delivery of these enantiomeric excesses to the early Earth may have contributed to the origin of the homochirality that is central to life on Earth today. This talk will explore the amino acids in carbonaceous chondritcs and their relevance to the origin of life.

  16. Review of chiral perturbation theory

    Indian Academy of Sciences (India)

    Abstract. A review of chiral perturbation theory and recent developments on the comparison of its predictions with experiment is presented. Some interesting topics with scope for further elaboration are touched upon.

  17. Homogenization of resonant chiral metamaterials

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Menzel, C.; Rockstuhl, Carsten

    2010-01-01

    Homogenization of metamaterials is a crucial issue as it allows to describe their optical response in terms of effective wave parameters as, e.g., propagation constants. In this paper we consider the possible homogenization of chiral metamaterials. We show that for meta-atoms of a certain size...... an analytical criterion for performing the homogenization and a tool to predict the homogenization limit. We show that strong coupling between meta-atoms of chiral metamaterials may prevent their homogenization at all....

  18. Chiral thermodynamics of nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    Fiorilla, Salvatore

    2012-10-23

    The equation of state of nuclear matter is calculated at finite temperature in the framework of in-medium chiral perturbation theory up to three-loop order. The dependence of its thermodynamic properties on the isospin-asymmetry is investigated. The chiral quark condensate is evaluated for symmetric nuclear matter. Its behaviour as a function of density and temperature sets important nuclear physics constraints for the QCD phase diagram.

  19. Meta-Chirality: Fundamentals, Construction and Applications

    Directory of Open Access Journals (Sweden)

    Xiaoliang Ma

    2017-05-01

    Full Text Available Chiral metamaterials represent a special type of artificial structures that cannot be superposed to their mirror images. Due to the lack of mirror symmetry, cross-coupling between electric and magnetic fields exist in chiral mediums and present unique electromagnetic characters of circular dichroism and optical activity, which provide a new opportunity to tune polarization and realize negative refractive index. Chiral metamaterials have attracted great attentions in recent years and have given rise to a series of applications in polarization manipulation, imaging, chemical and biological detection, and nonlinear optics. Here we review the fundamental theory of chiral media and analyze the construction principles of some typical chiral metamaterials. Then, the progress in extrinsic chiral metamaterials, absorbing chiral metamaterials, and reconfigurable chiral metamaterials are summarized. In the last section, future trends in chiral metamaterials and application in nonlinear optics are introduced.

  20. Molecular properties of astaxanthin in water/ethanol solutions from computer simulations

    OpenAIRE

    Karki, Khadga Jung; Samanta, Susruta; Roccatano, Danilo

    2016-01-01

    Astaxanthin (AXT) is a reference model of xanthophyll carotenoids, which is used in medicine and food industry, and has potential applications in nanotechnology. Because of its importance, there is a great interest in understanding its molecular properties and aggregation mechanism in water and mixed solvents. In this paper, we report a novel model of AXT for molecular dynamics simulation. The model is used to estimate different properties of the molecule in pure solutions and in water/ethano...

  1. Media Screening for Obtaining Haematococcus pluvialis Red Motile Macrozooids Rich in Astaxanthin and Fatty Acids.

    Science.gov (United States)

    Butler, Thomas O; McDougall, Gordon J; Campbell, Raymond; Stanley, Michele S; Day, John G

    2017-12-26

    Astaxanthin from Haematococcus pluvialis is commercially produced in a two-stage process, involving green vegetative (macrozooid) and red aplanospore stages. This approach has been scaled up to an industrial process but constraints limit its commercial success and profitability, including: contamination issues, high pigment extraction costs, requirements for high light levels and photo-bleaching in the red stage. However, in addition to the aplanospore stage, this alga can produce astaxanthin in vegetative palmelloid and motile macrozooid cells. In this study, a two-stage process utilising different media in the green stage, with subsequent re-suspension in medium without nitrate was employed to optimise the formation of red motile macrozooids. Optimal growth in the green phase was obtained on cultivation under mixotrophic conditions in EG:JM media followed by re-suspension in medium without nitrate resulting in red motile macrozooids with an astaxanthin content of 2.74% (78.4% of total carotenoids) and a lipid content of 35.3% (rich in unsaturated fatty acids. It is envisaged that the red motile macrozooids could be harvested and fed as a whole-cell product directly in the animal feed and aquaculture sectors, or used as a blend of carotenoids and polyunsaturated fatty acids (PUFAs) in nutraceutical products.

  2. Cell-wall disruption and lipid/astaxanthin extraction from microalgae: Chlorella and Haematococcus.

    Science.gov (United States)

    Kim, Dong-Yeon; Vijayan, Durairaj; Praveenkumar, Ramasamy; Han, Jong-In; Lee, Kyubock; Park, Ji-Yeon; Chang, Won-Seok; Lee, Jin-Suk; Oh, You-Kwan

    2016-01-01

    Recently, biofuels and nutraceuticals produced from microalgae have emerged as major interests, resulting in intensive research of the microalgal biorefinery process. In this paper, recent developments in cell-wall disruption and extraction methods are reviewed, focusing on lipid and astaxanthin production from the biotechnologically important microalgae Chlorella and Haematococcus, respectively. As a common, critical bottleneck for recovery of intracellular components such as lipid and astaxanthin from these microalgae, the composition and structure of rigid, thick cell-walls were analyzed. Various chemical, physical, physico-chemical, and biological methods applied for cell-wall breakage and lipid/astaxanthin extraction from Chlorella and Haematococcus are discussed in detail and compared based on efficiency, energy consumption, type and dosage of solvent, biomass concentration and status (wet/dried), toxicity, scalability, and synergistic combinations. This report could serve as a useful guide to the implementation of practical downstream processes for recovery of valuable products from microalgae including Chlorella and Haematococcus. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Assessing contamination of microalgal astaxanthin producer Haematococcus cultures with high-resolution melting curve analysis.

    Science.gov (United States)

    Dawidziuk, Adam; Popiel, Delfina; Luboinska, Magda; Grzebyk, Michal; Wisniewski, Maciej; Koczyk, Grzegorz

    2017-05-01

    Due to its superior antioxidant capabilities and higher activity than other carotenoids, astaxanthin is used widely in the nutraceutical and medicine industries. The most prolific natural producer of astaxanthin is the unicellular green microalga Haematococcus pluvialis. The correct identification of any contaminants in H. pluvialis cultures is both essential and nontrivial for several reasons. Firstly, while it is possible to distinguish the main microalgal contaminant Coelastrella sp. (in H. pluvialis cultures), in practice, it is frequently a daunting and error-prone task for personnel without extensive experience in the microscopic identification of algal species. Secondly, the undetected contaminants may decrease or stop production of astaxanthin. Lastly, the presence of other contaminants such as fungi can eventually infect and destroy the whole algae collection. In this study, high-resolution melting (HRM) analysis was developed to detect microalgal and fungal contamination. The developed diagnostic procedure allowed to distinguish pure H. pluvialis samples from cultures contaminated with low amounts (1.25 ng/ml) of microalgal DNA and fungal DNA (2.5 ng/ml). Such discrimination is not possible with the use of microscopy observations and allows fast and efficient collection testing.

  4. Conversion of β-carotene into astaxanthin: Two separate enzymes or a bifunctional hydroxylase-ketolase protein?

    Directory of Open Access Journals (Sweden)

    Gudiña Eduardo

    2008-02-01

    Full Text Available Abstract Astaxanthin is a xanthophyll of great interest in animal nutrition and human health. The market prospect in the nutraceutics industries for this health-protective molecule is very promising. Astaxanthin is synthesized by several bacteria, algae and plants from β-carotene by the sequential action of two enzymes: a β-carotene, 3,3'-hydroxylase that introduces an hydroxyl group at the 3 (and 3' positions of each of the two β-ionone rings of β-carotene, and a β-carotene ketolase that introduces keto groups at carbons 4 and 4' of the β-ionone rings. Astaxanthin is also produced by the yeast-like basidiomycete Xanthophyllomyces dendrorhous. A gene crtS involved in the conversion of β-carotene to astaxanthin has been cloned simultaneously by two research groups. Complementation studies of X. dendrorhous mutants and expression analysis in Mucor circinelloides reveals that the CrtS enzyme is a β-carotene hydroxylase of the P-450 monooxygenase family that converts β-carotene to the hydroxylated derivatives β-cryptoxanthin and zeaxanthin, but it does not form astaxanthin or the ketolated intermediates in this fungus. A bifunctional β-carotene hydroxylase-ketolase activity has been proposed for the CrtS protein. The evidence for and against this hypothesis is analyzed in detail in this review.

  5. Two-step cultivation for production of astaxanthin in Chlorella zofingiensis using a patented energy-free rotating floating photobioreactor (RFP).

    Science.gov (United States)

    Zhang, Zhao; Huang, Jim Junhui; Sun, Dongzhe; Lee, Yuankun; Chen, Feng

    2017-01-01

    In the present study, high light and nitrogen starvation with glucose-fed to the culture was found efficient to induce astaxanthin accumulation in Chlorella zofingiensis. Therefore, a two-step cultivation strategy including high biomass yield fermentation and outdoor induction with an energy-free RFP was conducted. During the fermentation, the highest cell density of 98.4gL(-1) and astaxanthin yield of 73.3mgL(-1) were achieved, which were higher than those so far reported in C. zofingiensis. During the outdoor induction, astaxanthin content was further increased by 1.5-fold leading to the highest astaxanthin productivity of 5.26mgL(-1)day(-1) under an optimal dilution of 5-fold. Our work thus provided an effective two-step cultivation strategy for production of astaxanthin by C. zofingiensis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. The Effect of Astaxanthin-Rich Microalgae “Haematococcus pluvialis” and Wholemeal Flours Incorporation in Improving the Physical and Functional Properties of Cookies

    Science.gov (United States)

    Hossain, A. K. M. Mofasser; Brennan, Margaret A.; Mason, Susan L.; Guo, Xinbo; Zeng, Xin An

    2017-01-01

    Marine-based food supplements can improve human nutrition. In an effort to modulate glycaemic response and enhance nutritional aspects, marine-derived algal food rich in astaxanthin was used in the formulation of a model food (wholemeal cookie). Astaxanthin substitution of cookies made from three flours (wheat, barley and oat) demonstrated a significant reduction in the rate of glucose released during in vitro digestion together with an increase in the total phenolic content (TPC) and antioxidant capacity of the food. The significantly (p cookies with 15% astaxanthin, followed by 10% and then 5% astaxanthin in comparison with control cookies of each flour. Total phenolic content, DPPH radical scavenging and Oxygen Radical Absorbance Capacity (ORAC) value also notably increased with increase in astaxanthin content. The results evidence the potential use of microalgae to enhance the bioactive compounds and lower the glycaemic response of wholemeal flour cookie. PMID:28933728

  7. Chirality in adsorption on solid surfaces.

    Science.gov (United States)

    Zaera, Francisco

    2017-12-07

    In the present review we survey the main advances made in recent years on the understanding of chemical chirality at solid surfaces. Chirality is an important topic, made particularly relevant by the homochiral nature of the biochemistry of life on Earth, and many chiral chemical reactions involve solid surfaces. Here we start our discussion with a description of surface chirality and of the different ways that chirality can be bestowed on solid surfaces. We then expand on the studies carried out to date to understand the adsorption of chiral compounds at a molecular level. We summarize the work published on the adsorption of pure enantiomers, of enantiomeric mixtures, and of prochiral molecules on chiral and achiral model surfaces, especially on well-defined metal single crystals but also on other flat substrates such as highly ordered pyrolytic graphite. Several phenomena are identified, including surface reconstruction and chiral imprinting upon adsorption of chiral agents, and the enhancement or suppression of enantioselectivity seen in some cases upon adsorption of enantiomixtures of chiral compounds. The possibility of enhancing the enantiopurity of adsorbed layers upon the addition of chiral seeds and the so-called "sergeants and soldiers" phenomenon are presented. Examples are provided where the chiral behavior has been associated with either thermodynamic or kinetic driving forces. Two main approaches to the creation of enantioselective surface sites are discussed, namely, via the formation of supramolecular chiral ensembles made out of small chiral adsorbates, and by adsorption of more complex chiral molecules capable of providing suitable chiral environments for reactants by themselves, via the formation of individual adsorbate:modifier adducts on the surface. Finally, a discussion is offered on the additional effects generated by the presence of the liquid phase often required in practical applications such as enantioselective crystallization, chiral

  8. Chiral Ramachandran Plots I: Glycine.

    Science.gov (United States)

    Baruch-Shpigler, Yael; Wang, Huan; Tuvi-Arad, Inbal; Avnir, David

    2017-10-24

    Ramachandran plots (RPs) map the wealth of conformations of the polypeptide backbone and are widely used to characterize protein structures. A limitation of the RPs is that they are based solely on two dihedral angles for each amino acid residue and provide therefore only a partial picture of the conformational richness of the protein. Here we extend the structural RP analysis of proteins from a two-dimensional (2D) map to a three-dimensional map by adding the quantitative degree of chirality-the continuous chirality measure (CCM)-of the amino acid residue at each point in the RP. This measure encompasses all bond angles and bond lengths of an amino acid residue. We focus in this report on glycine (Gly) because, due to its flexibility, it occupies a large portion of the 2D map, thus allowing a detailed study of the chirality measure, and in order to evaluate the justification of classically labeling Gly as the only achiral amino acid. We have analyzed in detail 4366 Gly residues extracted from high resolution crystallographic data of 160 proteins. This analysis reveals not only that Gly is practically always conformationally chiral, but that upon comparing with the backbone of all amino acids, the quantitative chirality values of Gly are of similar magnitudes to those of the (chiral) amino acids. Structural trends and energetic considerations are discussed in detail. Generally we show that adding chirality to Ramachandran plots creates far more informative plots that highlight the sensitivity of the protein structure to minor conformational changes.

  9. Authenticity of raspberry flavor in food products using SPME-chiral-GC-MS

    DEFF Research Database (Denmark)

    Hansen, Anne-Mette Sølvbjerg; Frandsen, Henrik Lauritz; Fromberg, Arvid

    2015-01-01

    flavor can be evaluated due to the fact that a natural flavor will consist almost exclusively of the R enantiomer, while a chemical synthesis of the same compound will result in a racemic mixture. 27 food products containing raspberry flavors where investigated using SPME-chiral-GC-MS. We found raspberry......A fast and simple method for authenticating raspberry flavors from food products was developed. The two enantiomers of the compound (E)-α-ionone from raspberry flavor were separated on a chiral gas chromatographic column. Based on the ratio of these two enantiomers the naturalness of a raspberry...... distribution of the R and S isomer. Two products were labelled to contain natural raspberry flavors but were found to contain almost equal amounts of both enantiomers indicating a presence of synthetic raspberry flavors only. Additionally, two products labelled to contain both raspberry juice and flavor showed...

  10. The determination of botanical origin of honeys based on enantiomer distribution of chiral volatile organic compounds.

    Science.gov (United States)

    Špánik, Ivan; Pažitná, Alexandra; Šiška, Peter; Szolcsányi, Peter

    2014-09-01

    The enantiomer ratios of chiral volatile organic compounds in rapeseed, chestnut, orange, acacia, sunflower and linden honeys were determined by multi-dimensional gas chromatography using solid phase microextraction (SPME) as a sample pre-treatment procedure. Linalool oxides, linalool and hotrienol were present at the highest concentration levels, while significantly lower amounts of α-terpineol, 4-terpineol and all isomers of lilac aldehydes were found in all studied samples. On the other hand, enantiomer distribution of some chiral organic compounds in honey depends on their botanical origin. The significant differences in enantiomer ratio of linalool were observed for rapeseed honey that allows us to distinguish this type of honey from the other ones. The enantiomer ratios of lilac aldehydes were useful for distinguishing of orange and acacia honey from other studied monofloral honeys. Similarly, different enantiomer ratio of 4-terpineol was found for sunflower honeys. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Chiral Phosphinate Degradation by the Fusarium Species: Scope and Limitation of the Process

    Directory of Open Access Journals (Sweden)

    Natalia Kmiecik

    2013-01-01

    Full Text Available Biodegradable capacities of fungal strains of Fusarium oxysporum (DSMZ 2018 and Fusarium culmorum (DSMZ 1094 were tested towards racemic mixture of chiral 2-hydroxy-2-(ethoxyphenylphosphinyl acetic acid—a compound with two stereogenic centres. The effectiveness of decomposition was dependent on external factors such as temperature and time of the process. Optimal conditions of complete mineralization were established. Both Fusarium species were able to biodegrade every isomer of tested compound at 30°C, but F. culmorum required 10 days and F. oxysporum 11 days to accomplish the process, which was continuously monitored using the 31P NMR technique.

  12. Chirality effects at each amino acid position on tripeptide self-assembly into hydrogel biomaterials

    Science.gov (United States)

    Marchesan, S.; Easton, C. D.; Styan, K. E.; Waddington, L. J.; Kushkaki, F.; Goodall, L.; McLean, K. M.; Forsythe, J. S.; Hartley, P. G.

    2014-04-01

    Hydrogels formed by ultrashort peptides are emerging as cost-effective materials for cell culture. However, l-peptides are labile to proteases, while their d-isomers are thought to not support cell growth as well. In contrast, the self-assembly behaviour and biological performance of heterochiral peptides (i.e., made of both d and l amino acids) are largely unknown. In this study, we evaluate the effects of amino acid chirality on tripeptide self-assembly and hydrogelation at physiological pH, and cytocompatibility in fibroblast cell culture. A series of uncapped hydrophobic tripeptides with all combinations of d, l amino acids was prepared, tested for self-assembly under physiological conditions, and analysed by circular dichroism, FT-IR, cryo-TEM, AFM, and Thioflavin T fluorescence imaging. Amino acid chirality has a profound effect on the peptides' supramolecular behaviour. Only selected isomers form hydrogels, and of amyloid structure, as confirmed by rheology and XRD. Importantly, they are able to maintain the viability and proliferation of fibroblasts in vitro. This study identifies two heterochiral gels that perform well in cell culture and will assist in the design of innovative and cost-effective peptide gel biomaterials.Hydrogels formed by ultrashort peptides are emerging as cost-effective materials for cell culture. However, l-peptides are labile to proteases, while their d-isomers are thought to not support cell growth as well. In contrast, the self-assembly behaviour and biological performance of heterochiral peptides (i.e., made of both d and l amino acids) are largely unknown. In this study, we evaluate the effects of amino acid chirality on tripeptide self-assembly and hydrogelation at physiological pH, and cytocompatibility in fibroblast cell culture. A series of uncapped hydrophobic tripeptides with all combinations of d, l amino acids was prepared, tested for self-assembly under physiological conditions, and analysed by circular dichroism, FT

  13. Chiral Phosphinate Degradation by the Fusarium Species: Scope and Limitation of the Process

    Science.gov (United States)

    Brzezińska-Rodak, Małgorzata

    2013-01-01

    Biodegradable capacities of fungal strains of Fusarium oxysporum (DSMZ 2018) and Fusarium culmorum (DSMZ 1094) were tested towards racemic mixture of chiral 2-hydroxy-2-(ethoxyphenylphosphinyl) acetic acid—a compound with two stereogenic centres. The effectiveness of decomposition was dependent on external factors such as temperature and time of the process. Optimal conditions of complete mineralization were established. Both Fusarium species were able to biodegrade every isomer of tested compound at 30°C, but F. culmorum required 10 days and F. oxysporum 11 days to accomplish the process, which was continuously monitored using the 31P NMR technique. PMID:24324893

  14. A Counterflow Diffusion Flame Study Of Branched Octane Isomers

    Science.gov (United States)

    2012-09-26

    public release; distribution is unlimited. A counterflow diffusion flame study of branched octane isomers The views, opinions and/or findings contained...MC 0934 La Jolla, CA 92093 -0934 ABSTRACT A counterflow diffusion flame study of branched octane isomers Report Title Conventional petroleum, Fischer...counterflow diffusion flame study of branched octane isomers Approved for public release; distribution is unlimited. 61657.7-EG REPORT DOCUMENTATION PAGE

  15. The interstellar chemistry of H2C3O isomers.

    Science.gov (United States)

    Loison, Jean-Christophe; Agúndez, Marcelino; Marcelino, Núria; Wakelam, Valentine; Hickson, Kevin M; Cernicharo, José; Gerin, Maryvonne; Roueff, Evelyne; Guélin, Michel

    2016-03-11

    We present the detection of two H2C3O isomers, propynal and cyclopropenone, toward various starless cores and molecular clouds, together with upper limits for the third isomer propadienone. We review the processes controlling the abundances of H2C3O isomers in interstellar media showing that the reactions involved are gas-phase ones. We show that the abundances of these species are controlled by kinetic rather than thermodynamic effects.

  16. Amplification of chirality in liquid crystals

    NARCIS (Netherlands)

    Eelkema, Rienk; Feringa, Ben L.

    2006-01-01

    The amplification of molecular chirality by liquid crystalline systems is widely applied in investigations towards enantioselective solvent - solute interactions, chiral supramolecular assemblies, smart materials, and the development of liquid crystal displays. Here we present an overview of recent

  17. Magnetic chirality as probed by neutron scattering

    Science.gov (United States)

    Simonet, V.; Loire, M.; Ballou, R.

    2012-11-01

    We review the concept of chirality, at first briefly in a general context then in the specific framework of the spin networks. We next discuss to what extent neutron scattering appears as an unconvertible tool to probe magnetic chirality in the static and dynamical regimes of the spins. The remarkable chiral ground state and excitations of the Fe-langasite compound finally serves to illustrate the use of neutron polarimetry in the experimental studies of the magnetic chirality.

  18. Quantum oscillations in the chiral magnetic conductivity

    Science.gov (United States)

    Kaushik, Sahal; Kharzeev, Dmitri E.

    2017-06-01

    In strong magnetic field, the longitudinal magnetoconductivity in three-dimensional chiral materials is shown to exhibit a new type of quantum oscillations arising from the chiral magnetic effect (CME). These quantum CME oscillations are predicted to dominate over the Shubnikov-de Haas (SdH) ones in chiral materials with an approximately conserved chirality of quasiparticles at strong magnetic fields. The phase of quantum CME oscillations differs from the phase of the conventional SdH oscillations by π /2 .

  19. Chiral dynamics of baryons in the perturbative chiral quark model

    Energy Technology Data Exchange (ETDEWEB)

    Pumsa-ard, K.

    2006-07-01

    In this work we develop and apply variants of a perturbative chiral quark model (PCQM) to the study of baryonic properties dominantly in the low-energy region. In a first step we consider a noncovariant form of the PCQM, where confinement is modelled by a static, effective potential and chiral corrections are treated to second order, in line with similar chiral quark models. We apply the PCQM to the study of the electromagnetic form factors of the baryon octet. We focus in particular on the low-energy observables such as the magnetic moments, the charge and magnetic radii. In addition, the electromagnetic N-delta transition is also studied in the framework of the PCQM. In the chiral loop calculations we consider a quark propagator, which is restricted to the quark ground state, or in hadronic language to nucleon and delta intermediate states, for simplicity. We furthermore include the low-lying excited states to the quark propagator. In particular, the charge radius of the neutron and the transverse helicity amplitudes of the N-delta transition are considerably improved by this additional effect. In a next step we develop a manifestly Lorentz covariant version of the PCQM, where in addition higher order chiral corrections are included. The full chiral quark Lagrangian is motivated by and in analogy to the one of Chiral Perturbation Theory (ChPT). This Lagrangian contains a set of low energy constants (LECs), which are parameters encoding short distance effects and heavy degrees of freedom. We evaluate the chiral Lagrangian to order O(p{sup 4}) and to one loop to generate the dressing of the bare quark operators by pseudoscalar mesons. In addition we include the vector meson degrees of freedom in our study. Projection of the dressed quark operators on the baryonic level serves to calculate the relevant matrix elements. In a first application of this scheme, we resort to a parameterization of the valence quark form factors in the electromagnetic sector. Constraints

  20. Technical Report on the Development of Mutant Paracoccus strain and Optimization of Medium Composition for the Mass Production of Astaxanthin

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jong Il; Lee, Ju Woon; Kim, Jae Hun; Song, Beom Seok

    2010-08-15

    Astaxanthin is used to role of provitamin A, and it is stronger antioxidant activity than vitamin E (100-500 times higher activity) and other carotenoids (10-fold). Furthermore, astaxanthin is also used as a nutraceutical and a medicinal ingredient against degenerative diseases such as cancer, heart disease, and skin related illness. The objective of this study was develop a carotenoid-hyperproducing mutant of Paracoccus N81106 using gamma irradiation and optimized medium composition. A mutant of Paracoccus having higher carotenoid content was isolated, and the production medium was optimized using response surface methodology. These results support that astaxanthin with strong antioxidant activity could be economically produced using the mutant and will be helpful for the related industry

  1. Chemical stability of astaxanthin integrated into a food matrix: Effects of food processing and methods for preservation.

    Science.gov (United States)

    Martínez-Delgado, Alejandra Anahí; Khandual, Sanghamitra; Villanueva-Rodríguez, Socorro Josefina

    2017-06-15

    Astaxanthin is a carotenoid pigment found in numerous organisms ranging from bacteria to algae, yeasts, plants, crustaceans and fish such as salmon. Technological importance of this pigment emerged from various studies demonstrating that it is a powerful antioxidant, even with higher activity than alpha-tocopherol and other carotenoids. It has been included in various pharmaceutical products because of several beneficial properties. By its nature, astaxanthin is susceptible to degradation and can undergo chemical changes during food processing. Therefore, different studies have focused on improving the stability of the carotenoid under conditions such as high temperatures, pressures and mechanical force, among others. In this review, common processes involved in food processing and their effect on the stability of astaxanthin, integrated into a food matrix are discussed. Moreover, preservation techniques such as microencapsulation, inclusion in emulsions, suspensions, liposomes, etc., that are being employed to maintain stability of the product are also reviewed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Viscoelastic modes in chiral liquid crystals

    Indian Academy of Sciences (India)

    amit@fs.rri.local.net (Amit Kumar Agarwal)

    our studies on the viscoelastic modes of some chiral liquid crystals using dynamic light scattering. We discuss viscoelastic modes corresponding to the C director fluctuations in the chiral smectic C phase and the behaviour of the Goldstone-mode near the chiral smectic C–smectic A phase transition. In cholesteric liquid ...

  3. Covariant perturbation theory and chiral superpropagators

    CERN Document Server

    Ecker, G

    1972-01-01

    The authors use a covariant formulation of perturbation theory for the non-linear chiral invariant pion model to define chiral superpropagators leading to S-matrix elements which are independent of the choice of the pion field coordinates. The relation to the standard definition of chiral superpropagators is discussed. (11 refs).

  4. Introduction to chiral symmetry in QCD

    Directory of Open Access Journals (Sweden)

    Sazdjian H.

    2017-01-01

    Full Text Available The main aspects of chiral symmetry in QCD are presented. The necessity of its spontaneous breakdown is explained. Some low-energy theorems are reviewed. The role of chiral effective Lagrangians in the formulation and realization of chiral perturbation theory is emphasized. The consequences of the presence of anomalies are sketched.

  5. Chirality and gravitational parity violation.

    Science.gov (United States)

    Bargueño, Pedro

    2015-06-01

    In this review, parity-violating gravitational potentials are presented as possible sources of both true and false chirality. In particular, whereas phenomenological long-range spin-dependent gravitational potentials contain both truly and falsely chiral terms, it is shown that there are models that extend general relativity including also coupling of fermionic degrees of freedom to gravity in the presence of torsion, which give place to short-range truly chiral interactions similar to that usually considered in molecular physics. Physical mechanisms which give place to gravitational parity violation together with the expected size of the effects and their experimental constraints are discussed. Finally, the possible role of parity-violating gravity in the origin of homochirality and a road map for future research works in quantum chemistry is presented. © 2015 Wiley Periodicals, Inc.

  6. Astaxanthin improves behavioral disorder and oxidative stress in prenatal valproic acid-induced mice model of autism.

    Science.gov (United States)

    Al-Amin, Md Mamun; Rahman, Md Mahbubur; Khan, Fazlur Rahman; Zaman, Fahmida; Mahmud Reza, Hasan

    2015-06-01

    Prenatal exposure to valproic acid on gestational day 12.5 may lead to the impaired behavior in the offspring, which is similar to the human autistic symptoms. To the contrary, astaxanthin shows neuroprotective effect by its antioxidant mechanism. We aimed to (i) develop mice model of autism and (ii) investigate the effect of astaxanthin on such model animals. Valproic acid (600 mg/kg) was administered intraperitoneally to the pregnant mice on gestational day 12.5. Prenatal valproic acid-exposed mice were divided into 2 groups on postnatal day 25 and astaxanthin (2mg/kg) was given to the experimental group (VPA_AST, n=10) while saline was given to the control group (VPA, n=10) for 4 weeks. Behavioral test including social interaction, open field and hot-plate were conducted on postnatal day 25 and oxidative stress markers such as lipid peroxidation, advanced protein oxidation product, nitric oxide, glutathione, and activity of superoxide dismutase and catalase were estimated on postnatal day 26 to confirm mice model of autism and on postnatal day 56 to assess the effect of astaxanthin. On postnatal day 25, prenatal valproic acid-exposed mice exhibited (i) delayed eye opening (ii) longer latency to respond painful stimuli, (iii) poor sociability and social novelty and (iv) high level of anxiety. In addition, an increased level of oxidative stress was found by determining different oxidative stress markers. Treatment with astaxanthin significantly (pstress in brain and liver. In conclusion, prenatal exposure to valproic day in pregnant mice leads to the development of autism-like features. Astaxanthin improves the impaired behavior in animal model of autism presumably by its antioxidant activity. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. PBPK modeling of the cis- and trans-permethrin isomers and their major urinary metabolites in rats.

    Science.gov (United States)

    Willemin, Marie-Emilie; Desmots, Sophie; Le Grand, Rozenn; Lestremau, François; Zeman, Florence A; Leclerc, Eric; Moesch, Christian; Brochot, Céline

    2016-03-01

    Permethrin, a pyrethroid insecticide, is suspected to induce neuronal and hormonal disturbances in humans. The widespread exposure of the populations has been confirmed by the detection of the urinary metabolites of permethrin in biomonitoring studies. Permethrin is a chiral molecule presenting two forms, the cis and the trans isomers. Because in vitro studies indicated a metabolic interaction between the trans and cis isomers of permethrin, we adapted and calibrated a PBPK model for trans- and cis-permethrin separately in rats. The model also describes the toxicokinetics of three urinary metabolites, cis- and trans-3-(2,2 dichlorovinyl)-2,2-dimethyl-(1-cyclopropane) carboxylic acid (cis- and trans-DCCA), 3-phenoxybenzoic acid (3-PBA) and 4'OH-phenoxybenzoic acid (4'-OH-PBA). In vivo experiments performed in Sprague-Dawley rats were used to calibrate the PBPK model in a Bayesian framework. The model captured well the toxicokinetics of permethrin isomers and their metabolites including the rapid absorption, the accumulation in fat, the extensive metabolism of the parent compounds, and the rapid elimination of metabolites in urine. Average hepatic clearances in rats were estimated to be 2.4 and 5.7 L/h/kg for cis- and trans-permethrin, respectively. High concentrations of the metabolite 4'-OH-PBA were measured in urine compared to cis- and trans-DCCA and 3-PBA. The confidence in the extended PBPK model was then confirmed by good predictions of published experimental data obtained using the isomers mixture. The extended PBPK model could be extrapolated to humans to predict the internal dose of exposure to permethrin from biomonitoring data in urine. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Evidence for an isomer in {sup 76}Ni

    Energy Technology Data Exchange (ETDEWEB)

    Sawicka, M.; Pfuetzner, M. [Institute of Experimental Physics, Warsaw University, PL-00-681, Warszawa (Poland); Grzywacz, R. [Institute of Experimental Physics, Warsaw University, PL-00-681, Warszawa (Poland); Physics Division, ORNL, TN 37831-6371, Oak Ridge (United States); Daugas, J.M.; Belier, G.; Sauvestre, J.E. [CEA Bruyeres-le-Chatel DIF/DPTA/SPN, BP 12, F-91680, Bruyeres-le-Chatel (France); Matea, I.; Lewitowicz, M.; Georgiev, G. [GANIL, BP 5027, F-14021, Caen Cedex (France); Grawe, H.; Mayet, P. [GSI, Planckstrasse 1, D-64291, Darmstadt (Germany); Becker, F. [GANIL, BP 5027, F-14021, Caen Cedex (France); GSI, Planckstrasse 1, D-64291, Darmstadt (Germany); Bingham, C. [Department of Physics and Astronomy, University of Tennessee, TN 37996, Knoxville (United States); Borcea, R.; Hammache, F.; Ibrahim, F. [IPN, 91406, Orsay Cedex (France); Bouchez, E. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191, Gif-sur-Yvette Cedex (France); Buta, A.; Dragulescu, E. [IFIN-HH, P.O. Box MG6, 76900, Bucharest-Magurele (Romania); Giovinazzo, J. [CENBG, BP 120, F-33175, Gradignan Cedex (France); Meot, V.; Negoita, F.; De Oliveira Santos, F.; Perru, O.; Roig, O.; Rykaczewski, K.P.; Saint-Laurent, M.G.; Sorlin, O.; Stanoiu, M.; Stefan, I.; Stodel, C.; Theisen, C.; Verney, D.

    2004-04-01

    In the experiment performed at the LISE2000 spectrometer at GANIL neutron-rich nickel isotopes were studied by microsecond isomer spectroscopy. Evidence for an isomer in {sup 76}Ni is found, consistently with the shell model prediction of an 8{sup +} state of {nu}(g{sub 9/2}){sup 2} structure. (orig.)

  9. Anaerobic Degradation of Lindane and Other HCH Isomers

    NARCIS (Netherlands)

    Mehboob, F.; Langenhoff, A.A.M.; Schraa, G.; Stams, A.J.M.

    2013-01-01

    Lindane (¿-HCH) is a pesticide that has mainly been used in agriculture. Lindane and the other HCH isomers are highly chlorinated hydrocarbons. The presence of a large number of electron withdrawing chlorine groups makes some of the HCH isomers rather recalcitrant in oxic environments. Especially

  10. Chiral symmetry in light-front QCD

    Science.gov (United States)

    Wu, Menh-Hsiu; Zhang, Wei-Min

    2004-04-01

    The definition of chiral transformations in light-front field theory is very different from the conventional form in equal-time formalism. We study the consistency of chiral transformations and chiral symmetry in light-front QCD and derive a complete new light-front axial-vector current for QCD. The breaking of chiral symmetry in light-front QCD is only associated with helicity flip interaction between quarks and gluons. Remarkably, the new axial-vector current does not contain the pion pole part so that the associate chiral charge smoothly describes pion transitions for various hadronic processes.

  11. Enantioselective syntheses of lignin models: an efficient synthesis of B-O-4 dimers and trimers by using the Evans chiral auxiliary

    Science.gov (United States)

    Costyl N. Njiojob; Joseph J. Bozell; Brian K. Long; Thomas Elder; Rebecca E. Key; William T. Hartwig

    2016-01-01

    We describe an efficient five-step, enantioselective synthesis of (R,R)- and (S,S)-lignin dimer models possessing a B-O-4 linkage, by using the Evans chiral aldol reaction as a key step. Mitsunobu inversion of the (R,R)- or (S,S)-isomers generates the corresponding (R,S)- and (S,R)-diastereomers. We further extend this approach to the...

  12. Photoprotection vs. Photoinhibition of Photosystem II in Transplastomic Lettuce (Lactuca sativa) Dominantly Accumulating Astaxanthin.

    Science.gov (United States)

    Fujii, Ritsuko; Yamano, Nami; Hashimoto, Hideki; Misawa, Norihiko; Ifuku, Kentaro

    2016-07-01

    Transplastomic (chloroplast genome-modified; CGM) lettuce that dominantly accumulates astaxanthin grows similarly to a non-transgenic control with almost no accumulation of naturally occurring photosynthetic carotenoids. In this study, we evaluated the activity and assembly of PSII in CGM lettuce. The maximum quantum yield of PSII in CGM lettuce was <0.6; however, the quantum yield of PSII was comparable with that in control leaves under higher light intensity. CGM lettuce showed a lower ability to induce non-photochemical quenching (NPQ) than the control under various light intensities. The fraction of slowly recovering NPQ in CGM lettuce, which is considered to be photoinhibitory quenching (qI), was less than half that of the control. In fact, 1 O 2 generation was lower in CGM than in control leaves under high light intensity. CGM lettuce contained less PSII, accumulated mostly as a monomer in thylakoid membranes. The PSII monomers purified from the CGM thylakoids bound echinenone and canthaxanthin in addition to β-carotene, suggesting that a shortage of β-carotene and/or the binding of carbonyl carotenoids would interfere with the photophysical function as well as normal assembly of PSII. In contrast, high accumulation of astaxanthin and other carbonyl carotenoids was found within the thylakoid membranes. This finding would be associated with the suppression of photo-oxidative stress in the thylakoid membranes. Our observation suggests the importance of a specific balance between photoprotection and photoinhibition that can support normal photosynthesis in CGM lettuce producing astaxanthin. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  13. Chiral acidic amino acids induce chiral hierarchical structure in calcium carbonate

    Science.gov (United States)

    Jiang, Wenge; Pacella, Michael S.; Athanasiadou, Dimitra; Nelea, Valentin; Vali, Hojatollah; Hazen, Robert M.; Gray, Jeffrey J.; McKee, Marc D.

    2017-04-01

    Chirality is ubiquitous in biology, including in biomineralization, where it is found in many hardened structures of invertebrate marine and terrestrial organisms (for example, spiralling gastropod shells). Here we show that chiral, hierarchically organized architectures for calcium carbonate (vaterite) can be controlled simply by adding chiral acidic amino acids (Asp and Glu). Chiral, vaterite toroidal suprastructure having a `right-handed' (counterclockwise) spiralling morphology is induced by L-enantiomers of Asp and Glu, whereas `left-handed' (clockwise) morphology is induced by D-enantiomers, and sequentially switching between amino-acid enantiomers causes a switch in chirality. Nanoparticle tilting after binding of chiral amino acids is proposed as a chiral growth mechanism, where a `mother' subunit nanoparticle spawns a slightly tilted, consequential `daughter' nanoparticle, which by amplification over various length scales creates oriented mineral platelets and chiral vaterite suprastructures. These findings suggest a molecular mechanism for how biomineralization-related enantiomers might exert hierarchical control to form extended chiral suprastructures.

  14. Identification of isomers of organometallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Mbue, Sona Peter; Cho, Kwang Hwi [Dept. of Bioinformatics and Life Science, School of Systems Biomedical Science, Soongsil University,Seoul (Korea, Republic of)

    2015-06-15

    The yaChI is a newly suggested chemical naming system. However, yaChI is a derivative of the IUPAC InChI with a modified algorithm that includes additional layers of chemical structure information. Consequently, yaChI string contains more structure details while preserving the original structure file information and can distinctively identify very closely related compounds reducing the chances of ambiguity in chemical compound databases as opposed to the general SMILES, InChI, and InChIKey. This study examines the relative performances of yaChI, SMILES, InChI, and InChIKey in duplication check for isomers. For simplicity, a small data set of 28 organometallic compounds (structural isomers of Rh-containing compounds) subdivided into three major groups (A, B, and C) based on the number and the type of ligands attached to the center atom was used to study the performances of each encoding scheme in describing chemical structures. SMILES, InChI, and InChIKey were generated using Openbabel and RDkit, whereas yaChI strings were generated with in-house program. Strings generated from SMILES, InChI, and InChIKey though different, resulted to only three unique chemical identifiers, with each belonging to one group indicating the presence of only three unique compounds in the study data. However, yaChI results depicted that all structures in each group are indeed unique and differ among themselves as well as those from other groups, mapping each structure with a unique identifier given a total number of 28 unique structures in the study data. This high perception of yaChI probe justifies its accuracy and reliability in duplication check among closely related compounds especially structures exhibiting stereo properties.

  15. Mesoscale structure of chiral nematic shells.

    Science.gov (United States)

    Zhou, Ye; Guo, Ashley; Zhang, Rui; Armas-Perez, Julio C; Martínez-González, José A; Rahimi, Mohammad; Sadati, Monirosadat; de Pablo, Juan J

    2016-11-09

    There is considerable interest in understanding and controlling topological defects in nematic liquid crystals (LCs). Confinement, in the form of droplets, has been particularly effective in that regard. Here, we employ a Landau-de Gennes formalism to explore the geometrical frustration of nematic order in shell geometries, and focus on chiral materials. By varying the chirality and thickness in uniform shells, we construct a phase diagram that includes tetravalent structures, bipolar structures (BS), bent structures and radial spherical structures (RSS). It is found that, in uniform shells, the BS-to-RSS structural transition, in response to both chirality and shell geometry, is accompanied by an abrupt change of defect positions, implying a potential use for chiral nematic shells as sensors. Moreover, we investigate thickness heterogeneity in shells and demonstrate that non-chiral and chiral nematic shells exhibit distinct equilibrium positions of their inner core that are governed by shell chirality c.

  16. Chiral flat bands: Existence, engineering, and stability

    Science.gov (United States)

    Ramachandran, Ajith; Andreanov, Alexei; Flach, Sergej

    2017-10-01

    We study flat bands in bipartite tight-binding networks with discrete translational invariance. Chiral flat bands with chiral symmetry eigenenergy E =0 and host compact localized eigenstates for finite range hopping. For a bipartite network with a majority sublattice chiral flat bands emerge. We present a simple generating principle of chiral flat-band networks and as a showcase add to the previously observed cases a number of new potentially realizable chiral flat bands in various lattice dimensions. Chiral symmetry respecting network perturbations—including disorder and synthetic magnetic fields—preserve both the flat band and the modified compact localized states. Chiral flat bands are spectrally protected by gaps and pseudogaps in the presence of disorder due to Griffiths effects.

  17. Asymmetric Synthesis via Chiral Aziridines

    DEFF Research Database (Denmark)

    Tanner, David Ackland; Harden, Adrian; Wyatt, Paul

    1996-01-01

    A series of chiral bis(aziridines) has been synthesised and evaluated as chelating ligands for a variety of asymmetric transformations mediated by metals [Os (dihydroxylation), Pd (allylic alkylation) Cu (cyclopropanation and aziridination, Li (1,2-addition of organolithiums to imines)]. In the b...

  18. Single chirality through crystal grinding

    NARCIS (Netherlands)

    Noorduin, W.L.

    2010-01-01

    The properties of chiral molecules in living organisms can be different for left- and right-handed molecules. Therefore, ways to produce molecules of single handedness are of paramount importance, especially for economical, high yielding processes to synthesize pharmaceutical compounds that must be

  19. Review of chiral perturbation theory

    Indian Academy of Sciences (India)

    the CLEO Collaboration. Other sources could be the decay τ →ππν. In the modern context, a fresh Roy equation analysis with the view of combining dis- persion relations with chiral perturbation theory has been carried out [20]. The evaluation of the inhomogeneous terms, the so-called 'driving terms' for the Roy equations ...

  20. Chiral phosphines in nucleophilic organocatalysis

    Directory of Open Access Journals (Sweden)

    Yumei Xiao

    2014-09-01

    Full Text Available This review discusses the tertiary phosphines possessing various chiral skeletons that have been used in asymmetric nucleophilic organocatalytic reactions, including annulations of allenes, alkynes, and Morita–Baylis–Hillman (MBH acetates, carbonates, and ketenes with activated alkenes and imines, allylic substitutions of MBH acetates and carbonates, Michael additions, γ-umpolung additions, and acylations of alcohols.

  1. Baryon and chiral symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Gorsky, A. [Institute for Theoretical and Experimental Physics (ITEP), Moscow, Russia and Moscow Institute of Physics and Technology (MIPT), Dolgoprudny (Russian Federation); Krikun, A. [NORDITA, KTH Royal Institute of Technology and Stockholm University Stockholm, Sweden and Institute for Theoretical and Experimental Physics (ITEP), Moscow (Russian Federation)

    2014-07-23

    We briefly review the generalized Skyrmion model for the baryon recently suggested by us. It takes into account the tower of vector and axial mesons as well as the chiral symmetry breaking. The generalized Skyrmion model provides the qualitative explanation of the Ioffe’s formula for the baryon mass.

  2. Algebraic study of chiral anomalies

    Indian Academy of Sciences (India)

    2012-06-14

    Jun 14, 2012 ... †Reproduced with kind permission from Springer Science+Business Media: Algebraic study of chiral anoma- lies, Juan Mañes, Raymond Stora and Bruno Zumino, Communications in Mathematical Physics 102, 157–174. (1985) Springer-Verlag. Even though at variance with normal Pramana policy, we ...

  3. Chiral Induction with Chiral Conformational Switches in the Limit of Low "Sergeants to Soldiers" Ratio

    DEFF Research Database (Denmark)

    Nuermaimaiti, Ajiguli; Bombis, Christian; Knudsen, Martin Markvard

    2014-01-01

    Molecular-level insights into chiral adsorption phenomena are highly relevant within the fields of asymmetric heterogeneous catalysis or chiral separation and may contribute to understand the origins of homochirality in nature. Here, we investigate chiral induction by the "sergeants and soldiers......" mechanism for an oligo(phenylene ethynylene) based chiral conformational switch by coadsorbing it with an intrinsically chiral seed on Au(111). Through statistical analysis of scanning tunneling microscopy (STM) data we demonstrate successful chiral induction with a very low concentration of seeding...

  4. Stereoisomeric separation and bioassay of a new organophosphorus compound, O,S-dimethyl-N-(2,2,2-trichloro-1-methoxyethyl)phosphoramidothioate: some implications for chiral switch.

    Science.gov (United States)

    Zhou, Shanshan; Wang, Lumei; Li, Ling; Liu, Weiping

    2009-08-12

    The manufacture and use of single- or enriched-enantiomer pesticides are green-chemistry developments advocated in the 21st century, but predictive work for chiral switch of newly produced chiral active ingredients is limited. In the present study, the stereoselective separation, target activity, and nontarget toxicity of O,S-dimethyl-N-(2,2,2-trichloro-1-methoxyethyl)phosphoramidothioate (MCP), a new organophosphorus compound, were investigated. Because being highly active and safe is a prerequisite for marketing single-isomer products, the above studies were used to offer some implications for the chiral switch of racemic MCP. The results showed that all four stereoisomers of MCP were successfully separated with a Chiralpak AD column on HPLC. The resolved isomers and the pairs of enantiomers were further distinguished using a circular dichroism detector, designating the first and third eluted peaks as one pair of enantiomers and the second and fourth peaks as the other pair. Then, the insecticidal activities and acute and delayed toxicities of the resolved isomers of MCP were evaluated by their acute lethal efficacy against Daphina magna , their inhibitory potentials to acetylcholinesterase (AChE), and axon-like outgrowth of the SH-SY5Y cells, respectively. The inhibition potencies of the isomers against AChE in SH-SY5Y cells were low and slightly stereoselective. On the other hand, a significant difference was observed among the isomers in their activities and delayed neurotoxicities. The 48 h acute toxicities of isomers to D. magna followed the order peak 1 approximately pair 1 (i.e., equimolar mixture of peaks 1 and 3) > peak 4 approximately racemate > pair 2 (i.e., equimolar mixture of peaks 2 and 4) > peak 2 > peak 3, with 1.0-6.3-fold differences among them. In comparison, the inhibitory potentials of the isomers toward axon growth of SH-SY5Y cells decreased in the order peak 2 > pair 2 > peak 4 > racemate > peak 3 > pair 1 approximately peak 1, with at

  5. Iterative tandem catalysis of secondary diols and diesters to chiral polyesters.

    Science.gov (United States)

    van As, Bart A C; van Buijtenen, Jeroen; Mes, Tristan; Palmans, Anja R A; Meijer, E W

    2007-01-01

    The well-known dynamic kinetic resolution of secondary alcohols and esters was extended to secondary diols and diesters to afford chiral polyesters. This process is an example of iterative tandem catalysis (ITC), a polymerization method where the concurrent action of two fundamentally different catalysts is required to achieve chain growth. In order to procure chiral polyesters of high enantiomeric excess value (ee) and good molecular weight, the catalysts employed need to be complementary and compatible during the polymerization reaction. We here show that Shvo's catalyst and Novozym 435 fulfil these requirements. The optimal polymerization conditions of 1,1'-(1,3-phenylene) diethanol (1,3-diol) and diisopropyl adipate required 2 mol% Shvo's catalyst and 12 mg Novozym 435 per mmol alcohol group in the presence of 0.5 M 2,4-dimethyl-3-pentanol as the hydrogen donor. With these conditions, chiral polyesters were obtained with peak molecular weights up to 15 kDa, an ee value up to 99% and with 1-3 % ketone end groups. Also with the structural isomer, 1,4-diol, a chiral polyester was obtained, albeit with lower molecular weight (8.3 kDa) and slightly lower ee (94%). Aliphatic secondary diols also resulted in enantio-enriched polymers but at most an ee of 46 % was obtained with molecular weights in the range of 3.3-3.7 kDa. This low ee originates from the intrinsic low enantioselectivity of Novozym 435 for this type of secondary aliphatic diols. The results presented here show that ITC can be applied to procure chiral polyesters with good molecular weight and high ee from optically inactive AA-BB type monomers.

  6. Supplementation of laying-hen feed with palm tocos and algae astaxanthin for egg yolk nutrient enrichment.

    Science.gov (United States)

    Walker, Laurie A; Wang, Tong; Xin, Hongwei; Dolde, David

    2012-02-29

    Adding supplements to hen feed can increase egg nutritional value. Astaxanthin, tocotrienols, and tocopherols are potent antioxidants that provide health benefits to humans. We hypothesized that the addition of these nutrients to hen feed would result in an increased nutrient content in egg yolk with minimum changes in functional properties. Laying hens (Hy-Line W-36 breed) were fed four diets with different supplementation levels of palm toco concentrate and algae biomass containing astaxanthin for 8 weeks. Egg yolks were analyzed for physical, chemical, and functional properties. The feed with the highest nutrient concentration was also studied for stability of these antioxidants using the Arrhenius approach. No significant differences were observed in functional properties except for emulsification capacity and sensory characteristics among eggs from different diet treatments. Changes in egg yolk color reached the maximum values at day 8. Incorporation of tocopherols and tocotrienols increased until day 8, astaxanthin incorporation increased until day 10, and all decreased thereafter. Feed nutrients resulted in a dose-response relationship of these compounds in the egg yolk. The transfer efficiency ranged from 0 to 9.9% for tocotrienols and tocopherols and from 7.6 to 14.9% for astaxanthin at their peak values. Results of the Arrhenius accelerated stability study showed significant differences in the shelf life of various nutrients, and these results can be used to properly formulate and store the feed materials.

  7. Differential expression of carotenogenic genes, associated changes on astaxanthin production and photosynthesis features induced by JA in H. pluvialis.

    Directory of Open Access Journals (Sweden)

    Zhengquan Gao

    Full Text Available Haematococcus pluvialis is an organism that under certain conditions can produce astaxanthin, an economically important carotenoid. In this study, the transcriptional expression patterns of eight carotenogenic genes of H. pluvialis in response to jasmonic acid (JA were evaluated using real-time PCR. Astaxanthin accumulation action and photosynthesis flourescence were monitored at the same time. The results showed all eight genes exhibited higher transcriptional expression significantly under JA treatments. JA25 (25 mg/L induction had greater effect (>10-fold up-regulation on the transcriptional expression of pds, crtR-B and lyc than on ipi-1, ipi-2, psy, bkt2, and crtO. JA50 (50 mg/L treatment had greater impact on the transcriptional expression of ipi-1, ipi-2, psy, crtR-B and crtO than on pds, lyc and bkt2. Astaxanthin biosynthesis in the presence of JA appeared to be up-regulated mainly by psy, pds, crtR-B, lyc, bkt2 and crtO at the transcriptional level and ipi-1, ipi-2 at both transcriptional and post-transcriptional levels. Under JA induction, the photosynthetic efficiency [Y (II] and the maximum quantum efficiency of PS II (Fv/Fm decreased significantly, but the non-photochemical quenching of chlorophyll fluorescence (NPQ increased drastically with the accumulation of astaxanthin.

  8. The Effect of Astaxanthin and Regular Training on Dynamic Pattern of Oxidative Stress on Male under Strenuous Exercise

    Science.gov (United States)

    Sylviana, N.; Gunawan, H.; Lesmana, R.; Purba, A.; Akbar, I. B.

    2017-03-01

    Strenuous physical activity will induced higher Reactive Oxygen Species (ROS) level in human body that can be measured by serum Malondialdehyde (MDA) level. Malondialdehyde is product of lipid peroxidation process that define as oxidative damage of lipid biomolecule by reactivity of reactive oxygen species. Still, the dynamic pattern of Malondialdehyde (MDA) level under strenuous exercise is not fully understood. Potent antioxidant such as Astaxanthin and training may be altered the level of MDA. Thus, purpose of this study is to understand effect of astaxanthin to MDA dynamic pattern on training male after strenuous physical activity. It was a double blind, experimental study, conducted on thirty young male age, divided into untrained and trained groups. Supplement Astaxanthin was given to 15 subject as well as placebo for one week after supplementation, Subjects were tested with anaerobic strenuous physical activity. The values were analyzed with ANOVA test followed by Duncan test showed that in every groups, mean of MDA before test was similar, start increase significantly after tested, begin decrease at 6th hour post test and back to baseline at 24th hour post-test ( pplacebo still increase twice from baseline. The lowest mean of MDA was found on group of trained male with Astaxanthin supplementation and the highest was found on group of untrained male with placebo (peffect to oxidative stress condition without altered its dynamic pattern in male after strenuous physical activity

  9. Astaxanthin Attenuates the Apoptosis of Retinal Ganglion Cells in db/db Mice by Inhibition of Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Xiao-Li Kang

    2013-03-01

    Full Text Available Diabetic retinopathy is a common diabetic eye disease caused by changes in retinal ganglion cells (RGCs. It is an ocular manifestation of systemic disease, which affects up to 80% of all patients who have had diabetes for 10 years or more. The genetically diabetic db/db mouse, as a model of type-2 diabetes, shows diabetic retinopathy induced by apoptosis of RGCs. Astaxanthin is a carotenoid with powerful antioxidant properties that exists naturally in various plants, algae and seafood. Here, astaxanthin was shown to reduce the apoptosis of RGCs and improve the levels of oxidative stress markers, including superoxide anion, malondialdehyde (MDA, a marker of lipid peroxidation, 8-hydroxy-2-deoxyguanosine (8-OHdG, indicator of oxidative DNA damage and MnSOD (manganese superoxide dismutase activity in the retinal tissue of db/db mouse. In addition, astaxanthin attenuated hydrogen peroxide(H2O2-induced apoptosis in the transformed rat retinal ganglion cell line RGC-5. Therefore, astaxanthin may be developed as an antioxidant drug to treat diabetic retinopathy.

  10. High performance liquid chromatography with photo diode array for separation and analysis of naproxen and esomeprazole in presence of their chiral impurities: Enantiomeric purity determination in tablets.

    Science.gov (United States)

    Ragab, Marwa A A; El-Kimary, Eman I

    2017-05-12

    A stereoselective high performance liquid chromatographic method with diode array detection (HPLC-DAD) was introduced for S-naproxen and esomeprazole determination in tablets. The separation was achieved on a Kromasil Cellucoat chiral column using a mobile phase consisting of hexane: isopropanol: trifluoroacetic acid (TFA) (90:9.9:0.1 v/v/v). The proposed system was found to be suitable for the enantioseparation of naproxen and omeprazole biologically active isomers. After optimization of the chromatographic conditions, resolution values of 3.84 and 2.17 could be obtained for naproxen and omeprazole isomers, respectively. The method was fully validated for the determination of S-isomers of each drug in their dosage form. Also, the enentiomeric purity was determined in commercial tablet containing S-naproxen and esomeprazole. The enantiomeric purity was calculated for each drug and the chiral impurities (R-isomers) could be determined at 1% level. The method was validated and good results with respect to linearity, precision, accuracy, selectivity and robustness were obtained. The limits of detection (LOD) and quantification (LOQ) were 2.00, 6.50 and 0.10, 0.35μgmL -1 for S-naproxen and esomeprazole, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. REVIEW ARTICLE: Chiral metamaterials: simulations and experiments

    Science.gov (United States)

    Wang, Bingnan; Zhou, Jiangfeng; Koschny, Thomas; Kafesaki, Maria; Soukoulis, Costas M.

    2009-11-01

    Electromagnetic metamaterials are composed of periodically arranged artificial structures. They show peculiar properties, such as negative refraction and super-lensing, which are not seen in natural materials. The conventional metamaterials require both negative epsilon and negative μ to achieve negative refraction. Chiral metamaterial is a new class of metamaterials offering a simpler route to negative refraction. In this paper, we briefly review the history of metamaterials and the developments on chiral metamaterials. We study the wave propagation properties in chiral metamaterials and show that negative refraction can be realized in chiral metamaterials with a strong chirality, with neither epsilon nor μ negative required. We have developed a retrieval procedure, adopting a uniaxial bi-isotropic model to calculate the effective parameters such as n ± , κ, epsilon and μ of the chiral metamaterials. Our work on the design, numerical calculations and experimental measurements of chiral metamaterials is introduced. Strong chiral behaviors such as optical activity and circular dichroism are observed and negative refraction is obtained for circularly polarized waves in these chiral metamaterials. We show that 3D isotropic chiral metamaterials can eventually be realized.

  12. Timoshenko beam model for chiral materials

    Science.gov (United States)

    Ma, T. Y.; Wang, Y. N.; Yuan, L.; Wang, J. S.; Qin, Q. H.

    2017-12-01

    Natural and artificial chiral materials such as deoxyribonucleic acid (DNA), chromatin fibers, flagellar filaments, chiral nanotubes, and chiral lattice materials widely exist. Due to the chirality of intricately helical or twisted microstructures, such materials hold great promise for use in diverse applications in smart sensors and actuators, force probes in biomedical engineering, structural elements for absorption of microwaves and elastic waves, etc. In this paper, a Timoshenko beam model for chiral materials is developed based on noncentrosymmetric micropolar elasticity theory. The governing equations and boundary conditions for a chiral beam problem are derived using the variational method and Hamilton's principle. The static bending and free vibration problem of a chiral beam are investigated using the proposed model. It is found that chirality can significantly affect the mechanical behavior of beams, making materials more flexible compared with nonchiral counterparts, inducing coupled twisting deformation, relatively larger deflection, and lower natural frequency. This study is helpful not only for understanding the mechanical behavior of chiral materials such as DNA and chromatin fibers and characterizing their mechanical properties, but also for the design of hierarchically structured chiral materials.

  13. Effects of astaxanthin and emodin on the growth, stress resistance and disease resistance of yellow catfish (Pelteobagrus fulvidraco).

    Science.gov (United States)

    Liu, Fei; Shi, Hong-Zhuan; Guo, Qiao-Sheng; Yu, Ye-Bing; Wang, Ai-Ming; Lv, Fu; Shen, Wen-Biao

    2016-04-01

    Yellow catfish (Pelteobagrus fulvidraco) has become a commercially important fish species in China and eastern Asia. High-density aquaculture has led to congestion and excessive stress and contributed to bacterial infection outbreaks that have caused high mortality. We investigated the effects of dietary supplementation with astaxanthin and emodin alone and in combination on the growth and stress resistance of yellow catfish. After 60 days of feeding, each group of fish (control, astaxanthin, emodin, and astaxanthin plus emodin (combination) groups) was exposed to acute crowding stress for 24 h, and a subsample of fish from the four groups was challenged with the bacterial septicemia pathogen Proteus mirabilis after the end of the crowding stress experiment. Compared with the control, the astaxanthin and emodin groups showed increases in serum total protein (TP), hepatic superoxide dismutase (SOD) activity and hepatic heat shock proteins 70 (HSP70) mRNA levels at 12 and 24 h after the initiation of crowding stress. The combination group exhibited increases in alanine aminotransferase (ALT) activity, aspartate aminotransferase (AST) activity, serum TP, hepatic SOD activity and hepatic HSP70 mRNA levels within 24 h after the initiation of crowding stress. However, decreases relative to the control were observed in the serum cortisol and glucose contents in the three treatment groups at 12 and 24 h after the initiation of crowding stress, in ALT and AST activity in the astaxanthin and emodin group at 24 h after the initiation of crowding stress, and in the serum lysozyme activity, serum alkaline phosphatase (ALP) activity, and hepatic catalase (CAT) and malondialdehyde (MDA) activity in the combination group at 24 h after the initiation of crowding stress. Additionally, the cumulative mortality after P. mirabilis infection was lower in all three treatment groups (57.00%-70.33%) than in the control (77.67%). Dietary supplementation with astaxanthin and emodin decreased

  14. The effect of astaxanthin on resistance of juvenile prawns Macrobrachium nipponense (Decapoda: Palaemonidae to physical and chemical stress

    Directory of Open Access Journals (Sweden)

    Babak Tizkar

    2014-12-01

    Full Text Available In recent years, the use of new scientific techniques has effectively improved aquaculture production processes. Astaxanthin has various properties in aquacultureand its antioxidant benefits have been closely related to stress resistance; besides, it is an essential factor for growth in many crustaceans and fish. The objective of this study was to evaluate the resistance of prawn (Macrobrachium nipponense fed diets containing different amounts of astaxanthin (AX to the shock and stress of differentphysicochemical environments. A 70-day trial was conducted to evaluate the effect of supplementation of a source of astaxanthin (Carophyll Pink, 10% astaxanthin, w/w, Hoffman-La Roche, Switzerland at various levels in the diet of M. nipponense juveniles. Four dry diets were prepared: AX0 without astaxanthin, AX50 with 50mg/kg, AX100 with 100mg/kg, and AX150 with 150mg/kg astaxanthin. The feeding trial was conducted in a recirculation water system consisting of 12 fiberglass tanks (1 000L used for holding prawns. Three replicate aquaria were initially stocked with 36org/m² per tank. During the trial, prawns were maintained on a 12:12-h light:dark photoperiod with an ordinary incandescent lamp, and the water quality parameters were maintained as follows: water temperature, 25-26°C; salinity, 1g/L; pH, 8.5-8.8; dissolved oxygen, 6.0-6.5mg/L; and ammonia-nitrogen, 0.05mg/L. Incorporation of AX, production output, and physiological condition were recorded after 10 weeks of feeding. At the end of the growing period, the prawns were exposed to thermal shock (0°C, ammonia (0.75mg/L, and reduced oxygen (0.5mg/L. The time to lethargyand the time to complete death of the prawns were recorded. The results showed that control prawns had the shortest time to lethargy and death compared with prawns subjected to the other treatments. The results of this study have shown that the amount of muscle tissue and gill carotenoids in prawn fed with an AX150 diet showed

  15. The effect of astaxanthin on resistance of juvenile prawns Macrobrachium nipponense (Decapoda: Palaemonidae) to physical and chemical stress.

    Science.gov (United States)

    Tizkar, Babak; Seidavi, Alireza; Ponce-Palafox, Jesús Trinidad; Pourashoori, Parastoo

    2014-12-01

    In recent years, the use of new scientific techniques has effectively improved aquaculture production processes. Astaxanthin has various properties in aquaculture and its antioxidant benefits have been closely related to stress resistance; besides, it is an essential factor for growth in many crustaceans and fish. The objective of this study was to evaluate the resistance of prawn (Macrobrachium nipponense) fed diets containing different amounts of astaxanthin (AX) to the shock and stress of different physicochemical environments. A 70-day trial was conducted to evaluate the effect of supplementation of a source of astaxanthin (Carophyll Pink, 10% astaxanthin, w/w, Hoffman-La Roche, Switzerland) at various levels in the diet of M. nipponense juveniles. Four dry diets were prepared: AX0 without astaxanthin, AX50 with 50 mg/kg, AX100 with 100 mg/kg, and AX150 with 150 mg/kg astaxanthin. The feeding trial was conducted in a recirculation water system consisting of 12 fiberglass tanks (1000L) used for holding prawns. Three replicate aquaria were initially stocked with 36 org/m2 per tank. During the trial, prawns were maintained on a 12:12-h light:dark photoperiod with an ordinary incandescent lamp, and the water quality parameters were maintained as follows: water temperature, 25-26°C; salinity, 1 g/L; pH, 8.5-8.8; dissolved oxygen, 6.0-6.5 mg/L; and ammonia-nitrogen, 0.05 mg/L. Incorporation of AX, production output, and physiological condition were recorded after 10 weeks of feeding. At the end of the growing period, the prawns were exposed to thermal shock (0°C), ammonia (0.75 mg/L), and reduced oxygen (0.5 mg/L). The time to lethargy and the time to complete death of the prawns were recorded. The results showed that control prawns had the shortest time to lethargy and death compared with prawns subjected to the other treatments. The results of this study have shown that the amount of muscle tissue and gill carotenoids in prawn fed with an AX150 diet showed

  16. Adsorption and Diffusion of Xylene Isomers on Mesoporous Beta Zeolite

    Directory of Open Access Journals (Sweden)

    Aixia Song

    2015-12-01

    Full Text Available A systematic and detailed analysis of adsorption and diffusion properties of xylene isomers over Beta zeolites with different mesoporosity was conducted. Adsorption isotherms of xylene isomers over microporous and mesoporous Beta zeolites through gravimetric methods were applied to investigate the impact of mesopores inside Beta zeolites on the adsorption properties of xylene isomers in the pressure range of lower 20 mbar. It is seen that the adsorption isotherms of three xylene isomers over microporous and mesoporous Beta zeolites could be successfully described by the single-site Toth model and the dual-site Toth model, respectively. The enhanced adsorption capacities and decreased Henry’s constants (KH and the initial heats of adsorption (Qst for the all xylene isomers are observed after the introduction of mesopores in the zeolites. For three xylene isomers, the order of Henry’s constant is o-xylene > m-xylene > p-xylene, whereas the adsorption capacities of Beta zeolite samples for xylene isomers execute the following order of o-xylene > p-xylene > m-xylene, due to the comprehensive effects from the molecular configuration and electrostatic interaction. At the same time, the diffusion properties of xylene isomers in the mesoporous Beta zeolites were also studied through the desorption curves measured by the zero length column (ZLC method at 333–373 K. It turned out that the effective diffusion time constant (Deff/R2 is a growing trend with the increasing mesoporosity, whereas the tendency of the activation energy is just the reverse, indicating the contribution of mesopores to facilitate molecule diffusion by shortening diffusion paths and reducing diffusion resistances. Moreover, the diffusivities of three xylene isomers in all Beta zeolites follow an order of p-xylene > m-xylene > o-xylene as opposed to KH, conforming the significant effects of adsorbate-adsorbent interaction on the diffusion.

  17. Detection of Actinides via Nuclear Isomer De-Excitation

    Energy Technology Data Exchange (ETDEWEB)

    Francy, Christopher J. [Oregon State Univ., Corvallis, OR (United States)

    2009-07-01

    This dissertation discusses a data collection experiment within the Actinide Isomer Identification project (AID). The AID project is the investigation of an active interrogation technique that utilizes nuclear isomer production, with the goal of assisting in the interdiction of illicit nuclear materials. In an attempt to find and characterize isomers belonging to 235U and its fission fragments, a 232Th target was bombarded with a monoenergetic 6Li ion beam, operating at 45 MeV.

  18. Heme isomers substantially affect heme's electronic structure and function

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta

    2017-01-01

    to similar energy of the isomers but with a sizable (25 kJ mol-1) barrier to interconversion arising from restricted rotation around the conjugated bonds. The four isomers, EE, EZ, ZE, and ZZ, were then investigated as 4-coordinate hemes, as 5-coordinate deoxyhemes, in 6-coordinate O2-adducts of globins.......e. the effects are not method-dependent. Thus, the nature of the isomer state is an important but overlooked feature of heme chemistry and function, and previous and future studies of hemes may be reconsidered in this new context....

  19. Properties of neutron-rich hafnium high-spin isomers

    CERN Multimedia

    Tungate, G; Walker, P M; Neyens, G; Billowes, J; Flanagan, K; Koester, U H; Litvinov, Y

    It is proposed to study highly-excited multi-quasiparticle isomers in neutron-rich hafnium (Z=72) isotopes. Long half-lives have already been measured for such isomers in the storage ring at GSI, ensuring their accessibility with ISOL production. The present proposal focuses on:\\\\ (i) an on-line experiment to measure isomer properties in $^{183}$Hf and $^{184}$Hf, and\\\\ (ii) an off-line molecular breakup test using REXTRAP, to provide Hf$^{+}$ beams for future laser spectroscopy and greater sensitivity for the future study of more neutron-rich isotopes.

  20. Chiral fullerenes from asymmetric catalysis.

    Science.gov (United States)

    Maroto, Enrique E; Izquierdo, Marta; Reboredo, Silvia; Marco-Martínez, Juan; Filippone, Salvatore; Martín, Nazario

    2014-08-19

    Fullerenes are among the most studied molecules during the last three decades, and therefore, a huge number of chemical reactions have been tested on these new carbon allotropes. However, the aim of most of the reactions carried out on fullerenes has been to afford chemically modified fullerenes that are soluble in organic solvents or even water in the search for different mechanical, optical, or electronic properties. Therefore, although a lot of effort has been devoted to the chemical functionalization of these molecular allotropes of carbon, important aspects in the chemistry of fullerenes have not been properly addressed. In particular, the synthesis of chiral fullerenes at will in an efficient manner using asymmetric catalysis has not been previously addressed in fullerene science. Thus, despite the fact that the chirality of fullerenes has always been considered a fundamental issue, the lack of a general stereoselective synthetic methodology has restricted the use of enantiopure fullerene derivatives, which have usually been obtained only after highly expensive HPLC isolation on specific chiral columns or prepared from a pool of chiral starting materials. In this Account, we describe the first stereodivergent catalytic enantioselective syntheses in fullerene science, which have allowed the highly efficient synthesis of enantiomerically pure derivatives with total control of the stereochemical result using metallic catalysts and/or organocatalysts under very mild conditions. Density functional theory calculations strongly support the experimental findings for the assignment of the absolute configuration of the new stereocenters, which has also been ascertained by application of the sector rule and single-crystal X-ray diffraction. The use of the curved double bond of fullerene cages as a two-π-electron component in a variety of stereoselective cycloaddition reactions represents a challenging goal considering that, in contrast to most of the substituted

  1. Application of derivative ratio spectrophotometry for determination of beta-carotene and astaxanthin from Phaffia rhodozyma extract.

    Science.gov (United States)

    Ni, Hui; He, Guo-qing; Ruan, Hui; Chen, Qi-he; Chen, Feng

    2005-06-01

    A derivative ratio spectrophotometric method was used for the simultaneous determination of beta-carotene and astaxanthin produced from Phaffia rhodozyma. Absorbencies of a series of the standard carotenoids in the range of 441 nm to 490 nm demonstrated that their absorptive spectra accorded with Beer's law and that the additivity when the concentrations of beta-carotene and astaxanthin and their mixture were within the range of 0 to 5 microg/ml, 0 to 6 microg/ml, and 0 to 6 microg/ml, respectively. When the wavelength interval (lambda) at 2 nm was selected to calculate the first derivative ratio spectra values, the first derivative amplitudes at 461 nm and 466 nm were suitable for quantitatively determining beta-carotene and astaxanthin, respectively. Effect of divisor on derivative ratio spectra could be neglected; any concentration used as divisor in range of 1.0 to 4.0 microg/ml is ideal for calculating the derivative ratio spectra values of the two carotenoids. Calibration graphs were established for beta-carotene within 0-6.0 microg/ml and for astaxanthin within 0-5.0 microg/ml with their corresponding regressive equations in: y=-0.0082x-0.0002 and y=0.0146x-0.0006, respectively. R-square values in excess of 0.999 indicated the good linearity of the calibration graphs. Sample recovery rates were found satisfactory (>99%) with relative standard deviations (RSD) of less than 5%. This method was successfully applied to simultaneous determination of beta-carotene and astaxanthin in the laboratory-prepared mixtures and the extract from the Phaffia rhodozyma culture.

  2. Application of derivative ratio spectrophotometry for determination of β-carotene and astaxanthin from Phaffia rhodozyma extract*

    Science.gov (United States)

    Ni, Hui; He, Guo-qing; Ruan, Hui; Chen, Qi-he; Chen, Feng

    2005-01-01

    A derivative ratio spectrophotometric method was used for the simultaneous determination of β-carotene and astaxanthin produced from Phaffia rhodozyma. Absorbencies of a series of the standard carotenoids in the range of 441 nm to 490 nm demonstrated that their absorptive spectra accorded with Beer’s law and that the additivity when the concentrations of β-carotene and astaxanthin and their mixture were within the range of 0 to 5 µg/ml, 0 to 6 µg/ml, and 0 to 6 µg/ml, respectively. When the wavelength interval (Δλ) at 2 nm was selected to calculate the first derivative ratio spectra values, the first derivative amplitudes at 461 nm and 466 nm were suitable for quantitatively determining β-carotene and astaxanthin, respectively. Effect of divisor on derivative ratio spectra could be neglected; any concentration used as divisor in range of 1.0 to 4.0 µg/ml is ideal for calculating the derivative ratio spectra values of the two carotenoids. Calibration graphs were established for β-carotene within 0–6.0 µg/ml and for astaxanthin within 0–5.0 µg/ml with their corresponding regressive equations in: y=−0.0082x−0.0002 and y=0.0146x−0.0006, respectively. R-square values in excess of 0.999 indicated the good linearity of the calibration graphs. Sample recovery rates were found satisfactory (>99%) with relative standard deviations (RSD) of less than 5%. This method was successfully applied to simultaneous determination of β-carotene and astaxanthin in the laboratory-prepared mixtures and the extract from the Phaffia rhodozyma culture. PMID:15909336

  3. Chiral heat wave and mixing of magnetic, vortical and heat waves in chiral media

    Energy Technology Data Exchange (ETDEWEB)

    Chernodub, M.N. [CNRS, Laboratoire de Mathématiques et Physique Théorique,Université de Tours, 37200 (France); Soft Matter Physics Laboratory, Far Eastern Federal University,Sukhanova 8, Vladivostok (Russian Federation); Department of Physics and Astronomy, University of Gent,Krijgslaan 281, S9, Gent (Belgium)

    2016-01-18

    We show that a hot rotating fluid of relativistic chiral fermions possesses a new gapless collective mode associated with coherent propagation of energy density and chiral density waves along the axis of rotation. This mode, which we call the Chiral Heat Wave, emerges due to a mixed gauge-gravitational anomaly. At finite density the Chiral Heat Wave couples to the Chiral Vortical Wave while in the presence of an external magnetic field it mixes with the Chiral Magnetic Wave. The coupling of the Chiral Magnetic and Chiral Vortical Waves is also demonstrated. We find that the coupled waves — which are coherent fluctuations of the vector, axial and energy currents — have generally different velocities compared to the velocities of the individual waves.

  4. Asymmetric Synthesis of Double Bond Isomers of the Structure Proposed for Pyrinodemin A and Indication of Its Structural Revision

    Directory of Open Access Journals (Sweden)

    Jun’ichi Kobayashi

    2005-01-01

    Full Text Available Asymmetric synthesis of double bond isomers ( -2 (∆15’,16’ and ( -3 (∆14’,15’ ofthe structure (1 (∆16’,17’ proposed for pyrinodemin A, a cytotoxic bis-pyridine alkaloidwith a unique cis-cyclopent[c]isoxazolidine moiety from a marine sponge, has beenaccomplished. Pyrinodemin A was indicated to be a 1:1 racemic mixture of 2 fromcomparison of C18 and chiral HPLC analysis for pyrinodemin A and the syntheticcompounds as well as ESIMS data of oxidative degradation products of pyrinodemin A.

  5. Isomers of nitric acid and chlorine nitrate

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, M.P.; Francl, M.M.; Rowland, F.S.; Hehre, W.J.

    1988-09-22

    Ab initio molecular orbital calculations at the HF/6-31G* and MP2/6-31G* levels have been performed on nitric acid and chlorine nitrate. Equilibrium geometries and electric dipole moments obtained from the MP2/6-31G* calculations are in good agreement with the respective experimental values, normal-mode (harmonic) vibrational frequencies and frequency shifts due to isotopic substitution calculated at this level support the most recent gas-phase infrared assignments for chlorine nitrate but suggest a reversal in the assignment of v/sub 5/ and v/sub 6/ for nitric acid. Calculations at the same levels of theory were also performed on peroxynitrous acid (HOONO) and chlorine peroxynitrite (ClOONO). The former is found to be 35 kcal/mol less stable than nitric acid at the MP2/6-31G* level; chlorine peroxynitrite is 30 kcal/mol higher in energy than chlorine nitrate. The possible role of these high-energy isomers in atmospheric processes is discussed.

  6. Chiral nanoparticles in singular light fields

    Science.gov (United States)

    Vovk, Ilia A.; Baimuratov, Anvar S.; Zhu, Weiren; Shalkovskiy, Alexey G.; Baranov, Alexander V.; Fedorov, Anatoly V.; Rukhlenko, Ivan D.

    2017-04-01

    The studying of how twisted light interacts with chiral matter on the nanoscale is paramount for tackling the challenging task of optomechanical separation of nanoparticle enantiomers, whose solution can revolutionize the entire pharmaceutical industry. Here we calculate optical forces and torques exerted on chiral nanoparticles by Laguerre-Gaussian beams carrying a topological charge. We show that regardless of the beam polarization, the nanoparticles are exposed to both chiral and achiral forces with nonzero reactive and dissipative components. Longitudinally polarized beams are found to produce chirality densities that can be 109 times higher than those of transversely polarized beams and that are comparable to the chirality densities of beams polarized circularly. Our results and analytical expressions prove useful in designing new strategies for mechanical separation of chiral nanoobjects with the help of highly focussed beams.

  7. Duality and symmetry in chiral Potts model

    Science.gov (United States)

    Roan, Shi-shyr

    2009-08-01

    We discover an Ising-type duality in the general N-state chiral Potts model, which is the Kramers-Wannier duality of a planar Ising model when N = 2. This duality relates the spectrum and eigenvectors of one chiral Potts model at a low temperature (of small k') to those of another chiral Potts model at a high temperature (of k'-1). The τ(2) model and chiral Potts model on the dual lattice are established alongside of the dual chiral Potts models. With the aid of this duality relation, we exact a precise relationship between the Onsager-algebra symmetry of a homogeneous superintegrable chiral Potts model and the sl2-loop-algebra symmetry of its associated spin- (N-1)/2 XXZ chain through the identification of their eigenstates.

  8. Objects of maximum electromagnetic chirality

    CERN Document Server

    Fernandez-Corbaton, Ivan

    2015-01-01

    We introduce a definition of the electromagnetic chirality of an object and show that it has an upper bound. The upper bound is attained if and only if the object is transparent for fields of one handedness (helicity). Additionally, electromagnetic duality symmetry, i.e. helicity preservation upon scattering, turns out to be a necessary condition for reciprocal scatterers to attain the upper bound. We use these results to provide requirements for the design of such extremal scatterers. The requirements can be formulated as constraints on the polarizability tensors for dipolar scatterers or as material constitutive relations. We also outline two applications for objects of maximum electromagnetic chirality: A twofold resonantly enhanced and background free circular dichroism measurement setup, and angle independent helicity filtering glasses.

  9. Chiral vortical effect for bosons

    Science.gov (United States)

    Avkhadiev, Artur; Sadofyev, Andrey V.

    2017-08-01

    The thermal contribution to the chiral vortical effect is believed to be related to the axial anomaly in external gravitational fields. We use the universality of the spin-gravity interaction to extend this idea to a wider set of phenomena. We consider the Kubo formula at weak coupling for the spin current of a vector field and derive a novel anomalous effect caused by the medium rotation: the chiral vortical effect for bosons. The effect consists in a spin current of vector bosons along the angular velocity of the medium. We argue that it has the same anomalous nature as in the fermionic case and show that this effect provides a mechanism for helicity transfer, from flow helicity to magnetic helicity.

  10. Symmetries of Ginsparg-Wilson Chiral Fermions

    OpenAIRE

    Mandula, Jeffrey E.

    2009-01-01

    The group structure of the variant chiral symmetry discovered by Luscher in the Ginsparg-Wilson description of lattice chiral fermions is analyzed. It is shown that the group contains an infinite number of linearly independent symmetry generators, and the Lie algebra is given explicitly. CP is an automorphism of this extended chiral group, and the CP transformation properties of the symmetry generators are found. The group has an infinite-parameter invariant subgroup, and the factor group, wh...

  11. CHIRALITY IN NONLINEAR OPTICS AND OPTICAL SWITCHING

    OpenAIRE

    Meijer, E. W.; Feringa, B. L.

    1993-01-01

    Chirality in molecular opto-electronics is limited sofar to the use of optically active liquid crystals and a number of optical phenomena are related to the helical macroscopic structure obtained by using one enantiomer, only. In this paper, the use of chirality in nonlinear optics and optical switching is demonstrated. The additional options offered by the combination of circularly polarized light and chiral molecules gives rise to the observation of Second Harmonic Generation from centrosym...

  12. Staggered chiral random matrix theory

    OpenAIRE

    Osborn, James C.

    2010-01-01

    We present a random matrix theory (RMT) for the staggered lattice QCD Dirac operator. The staggered RMT is equivalent to the zero-momentum limit of the staggered chiral Lagrangian and includes all taste breaking terms at their leading order. This is an extension of previous work which only included some of the taste breaking terms. We will also present some results for the taste breaking contributions to the partition function and the Dirac eigenvalues.

  13. Astaxanthin Inhibits Acetaldehyde-Induced Cytotoxicity in SH-SY5Y Cells by Modulating Akt/CREB and p38MAPK/ERK Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Tingting Yan

    2016-03-01

    Full Text Available Excessive alcohol consumption can lead to brain tissue damage and cognitive dysfunction. Acetaldehyde, the most toxic metabolite of ethanol, mediates the brain tissue damage and cognitive dysfunction induced by chronic excessive alcohol consumption. In this study, the effect of astaxanthin, a marine bioactive compound, on acetaldehyde-induced cytotoxicity was investigated in SH-SY5Y cells. It was found that astaxanthin protected cells from apoptosis by ameliorating the effect of acetaldehyde on the expression of Bcl-2 family proteins, preventing the reduction of anti-apoptotic protein Bcl-2 and the increase of pro-apoptotic protein Bak induced by acetaldehyde. Further analyses showed that astaxanthin treatment inhibited acetaldehyde-induced reduction of the levels of activated Akt and cyclic AMP-responsive element binding protein (CREB. Astaxanthin treatment also prevented acetaldehyde-induced increase of the level of activated p38 mitogen-activated protein kinase (MAPK and decrease of the level of activated extracellular signal-regulated kinases (ERKs. Activation of Akt/CREB pathway promotes cell survival and is involved in the upregulation of Bcl-2 gene. P38MAPK plays a critical role in apoptotic events while ERKs mediates the inhibition of apoptosis. Thus, astaxanthin may inhibit acetaldehyde-induced apoptosis through promoting the activation of Akt/CREB and ERKs and blocking the activation of p38MAPK. In addition, astaxanthin treatment suppressed the oxidative stress induced by acetaldehyde and restored the antioxidative capacity of SH-SY5Y cells. Therefore, astaxanthin may protect cells against acetaldehyde-induced cytotoxicity through maintaining redox balance and modulating apoptotic and survival signals. The results suggest that astaxanthin treatment may be beneficial for preventing neurotoxicity associated with acetaldehyde and excessive alcohol consumption.

  14. Functionalized Solvents for Olefin Isomer Purification by Reactive Extractive Distillation

    NARCIS (Netherlands)

    Kuipers, N.J.M.; Wentink, A.E.; de Haan, A.B.; Scholtz, J.; Mulder, H.

    2007-01-01

    Olefin isomer separations are difficult, energy intensive and thus expensive. An overview is presented to investigate the feasibility of metal–ligand complexes as functionalized solvents applied in a novel separation technology, reactive extractive distillation, for the separation and purification

  15. N-Protonated Isomers as Gateways to Peptide Ion Fragmentation

    National Research Council Canada - National Science Library

    Haeffner, Fredrik; Merle, John K; Irikura, Karl K

    2011-01-01

    .... If the intrinsic barrier to dissociation is the same for all backbone sites, the fragmentation propensity at each amide bond should reflect the stability of the corresponding N-protonated isomer...

  16. Carotenoids and Their Isomers: Color Pigments in Fruits and Vegetables

    Directory of Open Access Journals (Sweden)

    Yueming Jiang

    2011-02-01

    Full Text Available Fruits and vegetables are colorful pigment-containing food sources. Owing to their nutritional benefits and phytochemicals, they are considered as ‘functional food ingredients’. Carotenoids are some of the most vital colored phytochemicals, occurring as all-trans and cis-isomers, and accounting for the brilliant colors of a variety of fruits and vegetables. Carotenoids extensively studied in this regard include β-carotene, lycopene, lutein and zeaxanthin. Coloration of fruits and vegetables depends on their growth maturity, concentration of carotenoid isomers, and food processing methods. This article focuses more on several carotenoids and their isomers present in different fruits and vegetables along with their concentrations. Carotenoids and their geometric isomers also play an important role in protecting cells from oxidation and cellular damages.

  17. Simultaneous Determination of Two Isomers of Asarone in Piper ...

    African Journals Online (AJOL)

    Simultaneous Determination of Two Isomers of Asarone in Piper sarmentosum Roxburgh (Piperaceae) Extracts using Different Chromatographic Columns. Mohd Shahrul Ridzuan Hamil, Abdul Hakeem Memon, Amin Malik Shah Abdul Majid, Zhari Ismail ...

  18. Reelfoot/Lake Isom National Wildlife Refuge: Comprehensive Conservation Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan (CCP) was written to guide management on Reelfoot and Lake Isom NWRs for the next 15 years. This plan outlines the refuges'...

  19. Reelfoot and Lake Isom National Wildlife Refuges : Wildlife Inventory Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This wildlife inventory plan for Reelfoot and Lake Isom National Wildlife Refuges includes survey procedure forms that represent cost effective inventory of the...

  20. Chiral methyl-branched pheromones.

    Science.gov (United States)

    Ando, Tetsu; Yamakawa, Rei

    2015-07-01

    Insect pheromones are some of the most interesting natural products because they are utilized for interspecific communication between various insects, such as beetles, moths, ants, and cockroaches. A large number of compounds of many kinds have been identified as pheromone components, reflecting the diversity of insect species. While this review deals only with chiral methyl-branched pheromones, the chemical structures of more than one hundred non-terpene compounds have been determined by applying excellent analytical techniques. Furthermore, their stereoselective syntheses have been achieved by employing trustworthy chiral sources and ingenious enantioselective reactions. The information has been reviewed here not only to make them available for new research but also to understand the characteristic chemical structures of the chiral pheromones. Since biosynthetic studies are still limited, it might be meaningful to examine whether the structures, particularly the positions and configurations of the branched methyl groups, are correlated with the taxonomy of the pheromone producers and also with the function of the pheromones in communication systems.

  1. Chiral Symmetry in Light-front QCD

    OpenAIRE

    Wu, Meng-Hsiu; Zhang, Wei-Min

    2003-01-01

    The definition of chiral transformations in light-front field theory is very different from the conventional form in equal-time formalism. We study the consistency of chiral transformations and chiral symmetry in light-front QCD and derive a complete new light-front axial-vector current for QCD. The breaking of chiral symmetry in light-front QCD is only associated with helicity flip interaction between quarks and gluons. Remarkably, the new axial-vector current does not contain the pion pole ...

  2. Laser Writing of Multiscale Chiral Polymer Metamaterials

    Directory of Open Access Journals (Sweden)

    E. P. Furlani

    2012-01-01

    Full Text Available A new approach to metamaterials is presented that involves laser-based patterning of novel chiral polymer media, wherein chirality is realized at two distinct length scales, intrinsically at the molecular level and geometrically at a length scale on the order of the wavelength of the incident field. In this approach, femtosecond-pulsed laser-induced two-photon lithography (TPL is used to pattern a photoresist-chiral polymer mixture into planar chiral shapes. Enhanced bulk chirality can be realized by tuning the wavelength-dependent chiral response at both the molecular and geometric level to ensure an overlap of their respective spectra. The approach is demonstrated via the fabrication of a metamaterial consisting of a two-dimensional array of chiral polymer-based L-structures. The fabrication process is described and modeling is performed to demonstrate the distinction between molecular and planar geometric-based chirality and the effects of the enhanced multiscale chirality on the optical response of such media. This new approach to metamaterials holds promise for the development of tunable, polymer-based optical metamaterials with low loss.

  3. Highly Efficient Chirality Transfer from Diamines Encapsulated within a Self-Assembled Calixarene-Salen Host.

    Science.gov (United States)

    Martínez-Rodríguez, Luis; Bandeira, Nuno A G; Bo, Carles; Kleij, Arjan W

    2015-05-04

    A calix[4]arene host equipped with two bis-[Zn(salphen)] complexes self-assembles into a capsular complex in the presence of a chiral diamine guest with an unexpected 2:1 ratio between the host and the guest. Effective chirality transfer from the diamine to the calix-salen hybrid host is observed by circular dichroism (CD) spectroscopy, and a high stability constant K2,1 of 1.59×10(11)  M(-2) for the assembled host-guest ensemble has been determined with a substantial cooperativity factor α of 6.4. Density functional calculations are used to investigate the origin of the stability of the host-guest system and the experimental CD spectrum compared with those calculated for both possible diastereoisomers showing that the M,M isomer is the one that is preferentially formed. The current system holds promise for the chirality determination of diamines, as evidenced by the investigated substrate scope and the linear relationship between the ee of the diamine and the amplitude of the observed Cotton effects. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Developing chiral-technologies. Chiralty of fragrance; Hattensuru kiraru technology. Kaori no chiralty

    Energy Technology Data Exchange (ETDEWEB)

    Kumobayashi, H.; Yamamoto, K. [Takasago International Corp., Tokyo (Japan)

    1998-05-01

    This paper introduces the relation between chiralty and fragrance of optically active perfumes available by using an unconformity technology which uses rhodium, and ruthenium-BINAP complex catalysts. Chiral perfumes synthesized by unconformable isomerizing reaction are a citronellil derivative and have difference in fragrance between enantiomers. Ring compounds derived from citronellal 5 have greater identification degree in a smell receptor than chain compounds, and show relatively large difference in fragrance properties between optical isomers. Several kinds of new synthesized perfumes presenting amber-like fragrance have been developed. The 1`-hexane-3`-all 14 is one of these perfumes having superior trans form fragrance. The {delta}-decalactone 18 having strong fruit-like fragrance characteristics as a chiral perfume synthesized through unconformable hydrogenating reaction can be obtained by using unconformable hydrogeneating reaction of {alpha}-pentylidene cyclopentanone 16 as a key reaction. In association with advancement of catalytic unconformable synthesis technologies, it is expected that development of chiral perfumes will become more active. 5 refs., 4 tabs.

  5. Application of an unusual ninhydrin-based reaction for the indirect chiral resolution of D,L-penicillamine.

    Science.gov (United States)

    Sotgia, Salvatore; Zinellu, Angelo; Pinna, Gerard Aime; Deiana, Luca; Carru, Ciriaco

    2011-09-30

    An unusual reaction involving ninhydrin and aminothiols was exploited to set an indirect method for the chiral recognition of stereoisomers of penicillamine. Separation of diastereoisomers was achieved on a C18 column in isocratic mode by using a mixture of propionic acid (pH 3.0)/acetonitrile/water (10:10:80, v/v/v) as a mobile phase. Diastereoisomers were detected by a fluorescence detector in fairly short times (about 7 min) and with a good resolution. The lowest detectable amount of toxic isomer of penicillamine (l-enantiomer) in samples of the d-enantiomer, was around 0.01%. The method was also suitable for the indirect chiral recognition of other aminothiols such as cysteine and cysteinylglycine. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Chiral ruthenium(II polypyridyl complexes: stabilization of g-quadruplex DNA, inhibition of telomerase activity and cellular uptake.

    Directory of Open Access Journals (Sweden)

    Qianqian Yu

    Full Text Available Two ruthenium(II complexes, Λ-[Ru(phen(2(p-HPIP](2+ and Δ-[Ru(phen(2(p-HPIP](2+, were synthesized and characterized via proton nuclear magnetic resonance spectroscopy, electrospray ionization-mass spectrometry, and circular dichroism spectroscopy. This study aims to clarify the anticancer effect of metal complexes as novel and potent telomerase inhibitors and cellular nucleus target drug. First, the chiral selectivity of the compounds and their ability to stabilize quadruplex DNA were studied via absorption and emission analyses, circular dichroism spectroscopy, fluorescence-resonance energy transfer melting assay, electrophoretic mobility shift assay, and polymerase chain reaction stop assay. The two chiral compounds selectively induced and stabilized the G-quadruplex of telomeric DNA with or without metal cations. These results provide new insights into the development of chiral anticancer agents for G-quadruplex DNA targeting. Telomerase repeat amplification protocol reveals the higher inhibitory activity of Λ-[Ru(phen(2(p-HPIP](2+ against telomerase, suggesting that Λ-[Ru(phen(2(p-HPIP](2+ may be a potential telomerase inhibitor for cancer chemotherapy. MTT assay results show that these chiral complexes have significant antitumor activities in HepG2 cells. More interestingly, cellular uptake and laser-scanning confocal microscopic studies reveal the efficient uptake of Λ-[Ru(phen(2(p-HPIP](2+ by HepG2 cells. This complex then enters the cytoplasm and tends to accumulate in the nucleus. This nuclear penetration of the ruthenium complexes and their subsequent accumulation are associated with the chirality of the isomers as well as with the subtle environment of the ruthenium complexes. Therefore, the nucleus can be the cellular target of chiral ruthenium complexes for anticancer therapy.

  7. The Optical Chirality Flux as a Useful Far-Field Probe of Chiral Near Fields

    CERN Document Server

    Poulikakos, Lisa V; McPeak, Kevin M; Burger, Sven; Niegemann, Jens; Hafner, Christian; Norris, David J

    2016-01-01

    To optimize the interaction between chiral matter and highly twisted light, quantities that can help characterize chiral electromagnetic fields near nanostructures are needed. Here, by analogy with Poynting's theorem, we formulate the time-averaged conservation law of optical chirality in lossy dispersive media and identify the optical chirality flux as an ideal far-field observable for characterizing chiral optical near fields. Bounded by the conservation law, we show that it provides precise information, unavailable from circular dichroism spectroscopy, on the magnitude and handedness of highly twisted fields near nanostructures.

  8. Isomer-directed structural diversity and its effect on the nanosheet exfoliation and magnetic properties of 2,3-dimethylsuccinate hybrid frameworks.

    Science.gov (United States)

    Saines, Paul J; Steinmann, Mark; Tan, Jin-Chong; Yeung, Hamish H-M; Li, Wei; Barton, Phillip T; Cheetham, Anthony K

    2012-10-15

    The structures of seven new transition metal frameworks featuring Mn, Co, or Zn and either the meso or chiral D and L isomers of the 2,3-dimethylsuccinate ligand are reported. Frameworks that exhibit two-dimensional covalently bonded layers with weak interlayer interactions can be made with all three cations by incorporation of the chiral isomers of the 2,3-dimethylsuccinate ligand. The formation of such structures, suitable for the creation of nanosheets via exfoliation, is, however, not as ubiquitous as is the case with the 2,2-dimethylsuccinate frameworks since frameworks that incorporate the meso-2,3-dimethylsuccinate ligand form three-dimensional structures. This clear distinction between the formation of structures with covalent connectivity in two and three dimensions, depending on the choice of 2,3-dimethylsuccinate isomer, is due to the different conformations adopted by the backbone of the ligand. The chiral isomer prefers to adopt an arrangement with its methyl and carboxylate groups gauche to the neighboring functional groups of the same type, while the meso-ligand prefers to adopt trans geometry. A gauche-arrangement of the methyl groups places them on the same side of the ligand, making this geometry ideal for the formation of layered structures; a trans-relationship leads to the methyl groups being further apart, reducing their steric hindrance and making it easier to accommodate them within a three-dimensional structure. The ease of exfoliation of the layered frameworks is examined and compared to those of known transition metal 2,2-dimethylsuccinate frameworks by means of UV-vis spectroscopy. It is suggested that layered frameworks with more corrugated surfaces exfoliate more rapidly. The size, structure, and morphology of the exfoliated nanosheets are also characterized. The magnetic properties of the paramagnetic frameworks reveal that only the three dimensionally covalently bonded phases containing meso-2,3-DMS in trans-arrangements order

  9. In Vivo Effects of Free Form Astaxanthin Powder on Anti-Oxidation and Lipid Metabolism with High-Cholesterol Diet.

    Science.gov (United States)

    Chen, Yung-Yi; Lee, Pei-Chi; Wu, Yi-Long; Liu, Li-Yun

    2015-01-01

    Astaxanthin extracted from Pomacea canaliculata eggs was made into free-form astaxanthin powder (FFAP) and its effects on lipid metabolism, liver function, antioxidants activities and astaxanthin absorption rate were investigated. 45 hamsters were split into 5 groups and fed with normal diet, high-cholesterol control (0.2% cholesterol), 1.6FFAP (control+1.6% FFAP), 3.2FFAP (control+3.2% FFAP) and 8.0FFAP (control+8.0% FFAP), respectively, for 6 weeks. FFAP diets significantly decreased the liver total cholesterol, triglyceride levels and increased liver fatty acids (C20:5n3; C22:6n3) compositions. It decreased plasma alanine aminotransferase and aspartate aminotransferase. In terms of anti-oxidative activities, we found 8.0 FFAP diet significantly decreased plasma and liver malonaldehyde (4.96±1.96 μg TEP eq./mL and 1.56±0.38 μg TEP eq./g liver) and liver 8-isoprostane levels (41.48±13.69 μg 8-ISOP/g liver). On the other hand, it significantly increased liver catalase activity (149.10±10.76 μmol/min/g liver), Vitamin C (2082.97±142.23 μg/g liver), Vitamin E (411.32±81.67 μg/g liver) contents, and glutathione levels (2.13±0.42 mg GSH eq./g liver). Furthermore, 80% of astaxanthin absorption rates in all FFAP diet groups suggest FFAP is an effective form in astaxanthin absorption. Finally, astaxanthin was found to re-distribute to the liver and eyes in a dose dependent manner. Taken together, our results suggested that the appropriate addition of FFAP into high cholesterol diets increases liver anti-oxidative activity and reduces the concentration of lipid peroxidase and therefore, it may be beneficial as a material in developing healthy food.

  10. In Vivo Effects of Free Form Astaxanthin Powder on Anti-Oxidation and Lipid Metabolism with High-Cholesterol Diet.

    Directory of Open Access Journals (Sweden)

    Yung-Yi Chen

    Full Text Available Astaxanthin extracted from Pomacea canaliculata eggs was made into free-form astaxanthin powder (FFAP and its effects on lipid metabolism, liver function, antioxidants activities and astaxanthin absorption rate were investigated. 45 hamsters were split into 5 groups and fed with normal diet, high-cholesterol control (0.2% cholesterol, 1.6FFAP (control+1.6% FFAP, 3.2FFAP (control+3.2% FFAP and 8.0FFAP (control+8.0% FFAP, respectively, for 6 weeks. FFAP diets significantly decreased the liver total cholesterol, triglyceride levels and increased liver fatty acids (C20:5n3; C22:6n3 compositions. It decreased plasma alanine aminotransferase and aspartate aminotransferase. In terms of anti-oxidative activities, we found 8.0 FFAP diet significantly decreased plasma and liver malonaldehyde (4.96±1.96 μg TEP eq./mL and 1.56±0.38 μg TEP eq./g liver and liver 8-isoprostane levels (41.48±13.69 μg 8-ISOP/g liver. On the other hand, it significantly increased liver catalase activity (149.10±10.76 μmol/min/g liver, Vitamin C (2082.97±142.23 μg/g liver, Vitamin E (411.32±81.67 μg/g liver contents, and glutathione levels (2.13±0.42 mg GSH eq./g liver. Furthermore, 80% of astaxanthin absorption rates in all FFAP diet groups suggest FFAP is an effective form in astaxanthin absorption. Finally, astaxanthin was found to re-distribute to the liver and eyes in a dose dependent manner. Taken together, our results suggested that the appropriate addition of FFAP into high cholesterol diets increases liver anti-oxidative activity and reduces the concentration of lipid peroxidase and therefore, it may be beneficial as a material in developing healthy food.

  11. Chirally-modified metal surfaces: energetics of interaction with chiral molecules.

    Science.gov (United States)

    Dementyev, Petr; Peter, Matthias; Adamovsky, Sergey; Schauermann, Swetlana

    2015-09-21

    Imparting chirality to non-chiral metal surfaces by adsorption of chiral modifiers is a highly promising route to create effective heterogeneously catalyzed processes for the production of enantiopure pharmaceuticals. One of the major current challenges in heterogeneous chiral catalysis is the fundamental-level understanding of how such chirally-modified surfaces interact with chiral and prochiral molecules to induce their enantioselective transformations. Herein we report the first direct calorimetric measurement of the adsorption energy of chiral molecules onto well-defined chirally-modified surfaces. Two model modifiers 1-(1-naphthyl)ethylamine and 2-methylbutanoic acid were used to impart chirality to Pt(111) and their interaction with propylene oxide was investigated by means of single-crystal adsorption calorimetry. Differential adsorption energies and absolute surface uptakes were obtained for the R- and S-enantiomers of propylene oxide under clean ultrahigh vacuum conditions. Two types of adsorption behavior were observed for different chiral modifiers, pointing to different mechanisms of imparting chirality to metal surfaces. The results are analyzed and discussed in view of previously reported stereoselectivity of adsorption processes.

  12. Evaluation of Dalbavancin as chiral selector for HPLC and comparison with Teicoplanin based chiral stationary phases

    Science.gov (United States)

    ZHANG, XIAOTONG; BAO, YE; HUANG, KE; BARNETT-RUNDLETT, KIMBER L.; ARMSTRONG, DANIEL W.

    2015-01-01

    Dalbavancin is a new compound of the macrocyclic glycopeptide family. It was covalently linked to 5μm silica particles by using two different binding chemsitries. Approximately two hundred and fifty racemates including (A) heterocyclic compounds; (B) chiral acids; (C) chiral amines; (D) chiral alcohols; (E) chiral sulfoxides and sulfilimines; (F) amino acids and amino acid derivatives; and (G) other chiral compounds were tested on the two new chiral stationary phases (CSP) using three different mobile phases. As dalbavancin is structurally related to teicoplanin, the same set of chiral compounds was screened on two commercially available teicoplanin CSPs for comparison. The dalbavancin CSPs were able to separate some enantiomers that were not separated by the teicoplanin CSPs and also showed improved separations for many racemates. However, there were other compounds only separated or better separated on teicoplanin CSPS. Therefore, the dalbavancin CSPs are complementary to the teicoplanin CSPs. PMID:19676111

  13. The Metal Cation Chelating Capacity of Astaxanthin. Does This Have Any Influence on Antiradical Activity?

    Directory of Open Access Journals (Sweden)

    Ana Martínez

    2012-01-01

    Full Text Available In this Density Functional Theory study, it became apparent that astaxanthin (ASTA may form metal ion complexes with metal cations such as Ca+2, Cu+2, Pb+2, Zn+2, Cd+2 and Hg+2. The presence of metal cations induces changes in the maximum absorption bands which are red shifted in all cases. Therefore, in the case of compounds where metal ions are interacting with ASTA, they are redder in color. Moreover, the antiradical capacity of some ASTA-metal cationic complexes was studied by assessing their vertical ionization energy and vertical electron affinity, reaching the conclusion that metal complexes are slightly better electron donors and better electron acceptors than ASTA.

  14. Oil bodies as a potential microencapsulation carrier for astaxanthin stabilisation and safe delivery.

    Science.gov (United States)

    Acevedo, Francisca; Rubilar, Mónica; Jofré, Ignacio; Villarroel, Mario; Navarrete, Patricia; Esparza, Magdalena; Romero, Fernando; Vilches, Elías Alberto; Acevedo, Valentina; Shene, Carolina

    2014-01-01

    Astaxanthin (AST) is a valued molecule because of its high antioxidant properties. However, AST is extremely sensitive to oxidation, causing the loss of its bioactive properties. The purposes of this study were to define conditions for microencapsulating AST in oil bodies (OB) from Brassica napus to enhance its oxidative stability, and to test the bioactivity of the microencapsulated AST (AST-M) in cells. Conditions for maximising microencapsulation efficiency (ME) were determined using the Response Surface Methodology, obtaining a high ME (>99%). OB loaded with AST showed a strong electrostatic repulsion in a wide range of pH and ionic strengths. It was found that AST-M exposed to air and light was more stable than free AST. In addition, the protective effect of AST against intracellular ROS production was positively influenced by microencapsulation in OB. These results suggest that OB offer a novel option for stabilising and delivering AST.

  15. Preparation of enteric-coated microcapsules of astaxanthin oleoresin by complex coacervation.

    Science.gov (United States)

    Li, Rongli; Chen, Rencai; Liu, Weiwei; Qin, Cuiying; Han, Jing

    2016-10-25

    Astaxanthin oleoresin (AO) has a number of beneficial physiological functions. However, its sensitivity to light, heat, oxygen and gastric fluids has limited its application. In this paper, we describe the preparation of AO enteric microcapsules by coacervation to improve its stability and enteric solubility, and evaluate their efficacy by measuring the drug loading, encapsulation efficiency, optical microscopic appearance, stability, in vitro release and bioavailability. The results obtained showed that the AO enteric microcapsules possessed a high encapsulation efficiency (85.9%), a satisfactory in vitro release profile, and the ability of the microencapsulated AO to resist the effects of light, heat and oxygen was improved by 2.2-fold, 3.1-fold and 2.4-fold, respectively, during storage. In addition, the bioavailability of AO microcapsules was approximately 1.29-fold higher than AO, which is important for pharmaceutical applications and as a functional food.

  16. A spectral route to determining chirality

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Mortensen, Asger

    2009-01-01

    We show how one-dimensional structured media can be used to measure chirality, via the spectral shift of the photonic band gap edges. Analytically, we show that a chiral contrast can, in some cases, be mapped unto an index contrast, thereby greatly simplifying the analysis of such structures. Usi...

  17. CHIRALITY IN NONLINEAR OPTICS AND OPTICAL SWITCHING

    NARCIS (Netherlands)

    Meijer, E.W.; Feringa, B.L.

    1993-01-01

    Chirality in molecular opto-electronics is limited sofar to the use of optically active liquid crystals and a number of optical phenomena are related to the helical macroscopic structure obtained by using one enantiomer, only. In this paper, the use of chirality in nonlinear optics and optical

  18. Orientation-Dependent Handedness and Chiral Design

    Directory of Open Access Journals (Sweden)

    Efi Efrati

    2014-01-01

    Full Text Available Chirality occupies a central role in fields ranging from biological self-assembly to the design of optical metamaterials. The definition of chirality, as given by Lord Kelvin, associates chirality with the lack of mirror symmetry: the inability to superpose an object on its mirror image. While this definition has guided the classification of chiral objects for over a century, the quantification of handed phenomena based on this definition has proven elusive, if not impossible, as manifest in the paradox of chiral connectedness. In this work, we put forward a quantification scheme in which the handedness of an object depends on the direction in which it is viewed. While consistent with familiar chiral notions, such as the right-hand rule, this framework allows objects to be simultaneously right and left handed. We demonstrate this orientation dependence in three different systems—a biomimetic elastic bilayer, a chiral propeller, and optical metamaterial—and find quantitative agreement with chirality pseudotensors whose form we explicitly compute. The use of this approach resolves the existing paradoxes and naturally enables the design of handed metamaterials from symmetry principles.

  19. Chiral magnetic effect in condensed matter systems

    Science.gov (United States)

    Li, Qiang; Kharzeev, Dmitri E.

    2016-12-01

    The chiral magnetic effect (CME) is the generation of electrical current induced by chirality imbalance in the presence of magnetic field. It is a macroscopic manifestation of the quantum chiral anomaly [S. L. Adler. Axial-vector vertex in spinor electrodynamics. Physical Review, 177, 2426 (1969), J. S. Bell and R. Jackiw. A PCAC puzzle: π 0 γγin the σ-model. Il Nuovo Cimento A, 60, 47-61 (1969)] in systems possessing charged chiral fermions. In quark-gluon plasma containing nearly massless quarks, the chirality imbalance is sourced by the topological transitions. In condensed matter systems, the chiral quasiparticles emerge in gapless semiconductors with two energy bands having pointlike degeneracies opening the path to the study of chiral anomaly [H. B. Nielsen and M. Ninomiya. The Adler-Bell-Jackiw anomaly and Weyl fermions in a crystal. Physics Letters B, 130, 389-396 (1983)]. Recently, these novel materials - so-called Dirac and Weyl semimetals have been discovered experimentally, are suitable for the investigation of the CME in condensed matter experiments. Here we report on the first experimental observation of the CME in a 3D Dirac semimetal ZrTe5 [Q. Li, D. E. Kharzeev, C. Zhang, Y. Huang, I. Pletikosić, A. V. Fedorov, R. D. Zhong, J. A. Schneeloch, G. D. Gu, and T. Valla. Chiral magnetic effect in ZrTe5. Nature Physics (2016) doi:10.1038/nphys3648].

  20. High harmonic generation from axial chiral molecules.

    Science.gov (United States)

    Wang, Dian; Zhu, Xiaosong; Liu, Xi; Li, Liang; Zhang, Xiaofan; Lan, Pengfei; Lu, Peixiang

    2017-09-18

    Axial chiral molecules, whose stereogenic element is an axis rather than a chiral center, have attracted widespread interest due to their important application, such as asymmetric synthesis and chirality transfer. We investigate high harmonic generation from axial chiral molecules with bichromatic counterrotating circularly polarized laser fields. High harmonic generation from three typical molecules: (Sa)-3-chloropropa-1,2-dien-1-ol, propadiene, and (Ra)-2,3-pentadiene is simulated with time-dependent density-functional theory and strong field approximation. We found that harmonic spectra for 3D oriented axial chiral molecules exhibit obvious circular dichroism. However, the circular dichroism of High harmonic generation from an achiral molecule is much trivial. Moreover, the dichroism of high harmonic generation still exists when axial chiral molecules are 1D oriented,such as (Sa) -3-chloropropa-1,2-dien-1-ol. For a special form of axial chiral molecules with the formula abC=C=Cab (a, b are different substituents), like (Ra)-2,3-pentadiene, the dichroism discriminations disappear when the molecules are only in 1D orientation. The circular dichroism of high harmonic generation from axial chiral molecules is well explained by the trajectory analysis based on the semiclassical three-step mechanism.

  1. On infinite regular and chiral maps

    OpenAIRE

    Arredondo, John A.; Valdez, Camilo Ramírez y Ferrán

    2015-01-01

    We prove that infinite regular and chiral maps take place on surfaces with at most one end. Moreover, we prove that an infinite regular or chiral map on an orientable surface with genus can only be realized on the Loch Ness monster, that is, the topological surface of infinite genus with one end.

  2. Chiral gauge theories with domain wall fermions

    OpenAIRE

    Golterman, M.; Jansen, K.; Petcher, D.; Vink, J.

    1993-01-01

    We have investigated a proposal to construct chiral gauge theories on the lattice using domain wall fermions. The model contains two opposite chirality zeromodes, which live on two domain walls. We couple only one of them to a gauge field, but find that mirror fermions which also couple to the gauge field always seem to exist.

  3. Pentaquarks in chiral color dielectric model

    Indian Academy of Sciences (India)

    Abstract. Recent experiments indicate that a narrow baryonic state having strangeness. +1 and mass of about 1540 MeV may be existing. Such a state was predicted in chiral model by Diakonov et al. In this work I compute the mass and width of this state in chiral color dielectric model. I show that the computed width is ...

  4. Pentaquarks in chiral color dielectric model

    Indian Academy of Sciences (India)

    Recent experiments indicate that a narrow baryonic state having strangeness +1 and mass of about 1540 MeV may be existing. Such a state was predicted in chiral model by Diakonov et al. In this work I compute the mass and width of this state in chiral color dielectric model. I show that the computed width is about 30 MeV.

  5. Transport properties of chiral fermions

    Energy Technology Data Exchange (ETDEWEB)

    Puhr, Matthias

    2017-04-26

    Anomalous transport phenomena have their origin in the chiral anomaly, the anomalous non-conservation of the axial charge, and can arise in systems with chiral fermions. The anomalous transport properties of free fermions are well understood, but little is known about possible corrections to the anomalous transport coefficients that can occur if the fermions are strongly interacting. The main goal of this thesis is to study anomalous transport effects in media with strongly interacting fermions. In particular, we investigate the Chiral Magnetic Effect (CME) in a Weyl Semimetal (WSM) and the Chiral Separation Effect (CSE) in finite-density Quantum Chromodynamics (QCD). The recently discovered WSMs are solid state crystals with low-energy excitations that behave like Weyl fermions. The inter-electron interaction in WSMs is typically very strong and non-perturbative calculations are needed to connect theory and experiment. To realistically model an interacting, parity-breaking WSM we use a tight-binding lattice Hamiltonian with Wilson-Dirac fermions. This model features a non-trivial phase diagram and has a phase (Aoki phase/axionic insulator phase) with spontaneously broken CP symmetry, corresponding to the phase with spontaneously broken chiral symmetry for interacting continuum Dirac fermions. We use a mean-field ansatz to study the CME in spatially modulated magnetic fields and find that it vanishes in the Aoki phase. Moreover, our calculations show that outside of the Aoki phase the electron interaction has only a minor influence on the CME. We observe no enhancement of the magnitude of the CME current. For our non-perturbative study of the CSE in QCD we use the framework of lattice QCD with overlap fermions. We work in the quenched approximation to avoid the sign problem that comes with introducing a finite chemical potential on the lattice. The overlap operator calls for the evaluation of the sign function of a matrix with a dimension proportional to the volume

  6. Astaxanthin from Crayfish (Procambarus clarkii as a Pigmentary Ingredient in the Feed of Laying Hens

    Directory of Open Access Journals (Sweden)

    Garrido-Fernández, J.

    2008-06-01

    Full Text Available Chicken egg yolks generally owe their color to yellow carotenoids. The addition of synthetic red pigments allows changes in color, from the original yellow to red hues which may be more appealing to consumers in certain markets.Our aim has been to test whether ground crayfish shells, which are a rich and natural source of astaxanthin, produce detectable changes in the coloration of egg yolks through the accumulation of this carotenoid. Laying hens were fed with a commercial feed mixed with crayfish powder and the carotenoid profiles of the yolks in the eggs laid during the trial were monitored by HPLC. The analyses showed a progressive increase in the astaxanthin concentration in the egg yolks, reaching similar levels to those obtained for the rest of present carotenoid pigments.La yema de huevo de gallina debe su coloración a la presencia de carotenoides de tonalidad amarilla. La adición de colorantes sintéticos de tonalidades rojas permite modificar e incrementar la coloración de la yema desde el amarillo original a tonos rojos que pueden ser demandados en ciertos mercados según las preferencias del consumidor. El objetivo del trabajo fue probar si un triturado obtenido a partir de caparazones de cangrejo, que es una fuente natural y rica en astaxanteno, produce cambios detectables en la coloración de la yema de huevo por la acumulación de dicho carotenoide. Las gallinas ponedoras se alimentaron con un pienso comercial al que se adicionó triturado de caparazón de cangrejo. Se realizó un seguimiento de los cambios en la composición carotenoide (mediante HPLC de la yema de los huevos puestos durante el periodo de alimentación suplementada. Los análisis mostraron una progresiva incorporación de astaxanteno que alcanzó niveles similares al resto de carotenoides presentes inicialmente en la yema.

  7. Microwave chirality discrimination in enantiomeric liquids

    Science.gov (United States)

    Hollander, E.; Kamenetskii, E. O.; Shavit, R.

    2017-07-01

    Chirality discrimination is of fundamental interest in biology, chemistry, and metamaterial studies. In optics, near-field plasmon-resonance spectroscopy with superchiral probing fields is effectively applicable for analyses of large biomolecules with chiral properties. We show possibility for microwave near-field chirality discrimination analysis based on magnon-resonance spectroscopy. Newly developed capabilities in microwave sensing using magnetoelectric (ME) probing fields originated from multiresonance magnetic-dipolar-mode oscillations in quasi-2D yttrium-iron-garnet disks provide potential for unprecedented measurements of chemical and biological objects. We report on microwave near-field chirality discrimination for aqueous D- and L-glucose solutions. The shown ME-field sensing is addressed to deepen our understanding of microwave-biosystem interactions. It can also be important for an analysis and design of microwave chiral metamaterials.

  8. Centre vortex removal restores chiral symmetry

    Science.gov (United States)

    Trewartha, Daniel; Kamleh, Waseem; Leinweber, Derek B.

    2017-12-01

    The influence of centre vortices on dynamical chiral symmetry breaking is investigated through the light hadron spectrum on the lattice. Recent studies of the quark propagator and other quantities have provided evidence that centre vortices are the fundamental objects underpinning dynamical chiral symmetry breaking in {SU}(3) gauge theory. For the first time, we use the chiral overlap fermion action to study the low-lying hadron spectrum on lattice ensembles consisting of Monte Carlo, vortex-removed, and vortex-projected gauge fields. We find that gauge field configurations consisting solely of smoothed centre vortices are capable of reproducing all the salient features of the hadron spectrum, including dynamical chiral symmetry breaking. The hadron spectrum on vortex-removed fields shows clear signals of chiral symmetry restoration at light values of the bare quark mass, while at heavy masses the spectrum is consistent with a theory of weakly interacting constituent quarks.

  9. Enantioselective environmental toxicology of chiral pesticides.

    Science.gov (United States)

    Ye, Jing; Zhao, Meirong; Niu, Lili; Liu, Weiping

    2015-03-16

    The enantioselective environmental toxic effect of chiral pesticides is becoming more important. As the industry develops, increasing numbers of chiral insecticides and herbicides will be introduced into use, potentially posing toxic effects on nontarget living beings. Chiral pesticides, including herbicides such as acylanilides, phenoxypropanoic acids, and imidazolinones, and insecticides such as synthetic pyrethroids, organophosphates, and DDT often behave enantioselectively during agricultural use. These compounds also pose unpredictable enantioselective ecological threats to nontarget living beings and/or humans, affecting the food chain and entire ecosystems. Thus, to investigate the enantioselective toxic effects of chiral insecticides and herbicides is necessary during environmental protection. The environmental toxicology of chiral pesticides, especially the findings obtained from studies conducted in our laboratory during the past 10 years, is reviewed.

  10. Determining the number of isomers in X-, XY-, XYZ-, and XYZU-substituted D2 d allenes: Additive schemes for calculating enthalpies of vaporization

    Science.gov (United States)

    Nilov, D. Yu.; Smolyakov, V. M.

    2015-02-01

    Using Pólya's theorem, cycle indices are derived that identify the chiral and achiral substitution isomers of an allene (1,2-propadiene). Equations of symmetry that allow us to determine the number of isomers in a series and arrange the isomers according to families, depending on the number of substitution sites, are obtained. Eight- and nine-constant additive schemes based on the similarity between subgraphs in the molecular graphs (MGs) of a series of 120 molecules of X-, XY-, XYZ-, and XYZU-substituted allenes and the expansion of polygonal numbers (triangular, tetrahedral, and others) of a Pascal triangle are devised. Enthalpies of vaporization L NBP are calculated for 21 XY- and 120 XYZU-substituted allenes, respectively, not yet studied experimentally. It is shown that each coefficient of the scheme (the number of ways for superpositioning subgraphs with lengths i 1, i 2, ⋯ on molecular graphs of allene) is a result of partitioning triangular, tetrahedral, or four-dimensional tetrahedral numbers of a Pascal triangle.

  11. Genetically programmed chiral organoborane synthesis

    Science.gov (United States)

    Kan, S. B. Jennifer; Huang, Xiongyi; Gumulya, Yosephine; Chen, Kai; Arnold, Frances H.

    2017-12-01

    Recent advances in enzyme engineering and design have expanded nature’s catalytic repertoire to functions that are new to biology. However, only a subset of these engineered enzymes can function in living systems. Finding enzymatic pathways that form chemical bonds that are not found in biology is particularly difficult in the cellular environment, as this depends on the discovery not only of new enzyme activities, but also of reagents that are both sufficiently reactive for the desired transformation and stable in vivo. Here we report the discovery, evolution and generalization of a fully genetically encoded platform for producing chiral organoboranes in bacteria. Escherichia coli cells harbouring wild-type cytochrome c from Rhodothermus marinus (Rma cyt c) were found to form carbon–boron bonds in the presence of borane–Lewis base complexes, through carbene insertion into boron–hydrogen bonds. Directed evolution of Rma cyt c in the bacterial catalyst provided access to 16 novel chiral organoboranes. The catalyst is suitable for gram-scale biosynthesis, providing up to 15,300 turnovers, a turnover frequency of 6,100 h–1, a 99:1 enantiomeric ratio and 100% chemoselectivity. The enantiopreference of the biocatalyst could also be tuned to provide either enantiomer of the organoborane products. Evolved in the context of whole-cell catalysts, the proteins were more active in the whole-cell system than in purified forms. This study establishes a DNA-encoded and readily engineered bacterial platform for borylation; engineering can be accomplished at a pace that rivals the development of chemical synthetic methods, with the ability to achieve turnovers that are two orders of magnitude (over 400-fold) greater than those of known chiral catalysts for the same class of transformation. This tunable method for manipulating boron in cells could expand the scope of boron chemistry in living systems.

  12. Chiral discrimination in nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Lazzeretti, Paolo

    2017-11-01

    Chirality is a fundamental property of molecules whose spatial symmetry is characterized by the absence of improper rotations, making them not superimposable to their mirror image. Chiral molecules constitute the elementary building blocks of living species and one enantiomer is favoured in general (e.g. L-aminoacids and D-sugars pervade terrestrial homochiral biochemistry) because most chemical reactions producing natural substances are enantioselective. Since the effect of chiral chemicals and drugs on living beings can be markedly different between enantiomers, the quest for practical spectroscopical methods to scrutinize chirality is an issue of great importance and interest. Nuclear magnetic resonance (NMR) is a topmost analytical technique, but spectrometers currently used are ‘blind’ to chirality, i.e. unable to discriminate the two mirror-image forms of a chiral molecule, because, in the absence of a chiral solvent, the spectral parameters, chemical shifts and spin-spin coupling constants are identical for enantiomers. Therefore, the development of new procedures for routine chiral recognition would offer basic support to scientists. However, in the presence of magnetic fields, a distinction between true and false chirality is mandatory. The former epitomizes natural optical activity, which is rationalized by a time-even pseudoscalar, i.e. the trace of a second-rank tensor, the mixed electric dipole/magnetic dipole polarizability. The Faraday effect, magnetic circular dichroism and magnetic optical activity are instead related to a time-odd axial vector. The present review summarizes recent theoretical and experimental efforts to discriminate enantiomers via NMR spectroscopy, with the focus on the deep connection between chirality and symmetry properties under the combined set of fundamental discrete operations, namely charge conjugation, parity (space inversion) and time (motion) reversal.

  13. Biological variation of lipid constituents and distribution of tocopherols and astaxanthin in farmed Atlantic salmon (Salmo salar)

    DEFF Research Database (Denmark)

    Refsgaard, Hanne; Brockhoff, Per B; Jensen, Benny

    1998-01-01

    The contents of fat, astaxanthin, and tocogherols and the fatty acid composition of a homogeneous group of 145 farmed Atlantic salmon (Salmo salar) were determined. The analytical variation of the data was stastistically-separated from the biological variation. The fat content in the muscle near....... The concentrations of alpha-, gamma-, and delta-tocopherols were approximately 32, 2.9, and 0.4 mg/kg of muscle, respectively, and the biological standard deviations were 4.5, 0.4, and 0.07 mg/kg (14, 14, and 20%), respectively. in another group of five salmon the distributions throughout the fillet were determined......, longitudinally as well as transversally. The distribution of fat, astaxanthin, and tocopherols varied throughout the salmon. The fatty acid composition varied little between extracts from different locations of the fillet...

  14. Gradient domestication of Haematococcus pluvialis mutant with 15% CO2 to promote biomass growth and astaxanthin yield.

    Science.gov (United States)

    Cheng, Jun; Li, Ke; Yang, Zongbo; Lu, Hongxiang; Zhou, Junhu; Cen, Kefa

    2016-09-01

    In order to increase biomass yield and reduce culture cost of Haematococcus pluvialis with flue gas from coal-fired power plants, a screened mutant by nuclear irradiation was gradually domesticated with 15% CO2 to promote biomass dry weight and astaxanthin yield. The biomass yield of mutant after 10 generations of 15% CO2 domestication increased to 1.3 times as that with air. With the optimization of nitrogen and phosphorus concentration, the biomass dry weight was further increased by 62%. The astaxanthin yield induced with 15% CO2 and high light of 135 μmol photons m(-2) s(-1) increased to 87.4mg/L, which was 6 times higher than that induced with high light in air. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. A new high-spin isomer in {sup 195}Bi

    Energy Technology Data Exchange (ETDEWEB)

    Roy, T.; Mukherjee, G.; Rana, T.K.; Bhattacharya, Soumik; Asgar, Md.A.; Bhattacharya, C.; Bhattacharya, S.; Bhattacharyya, S.; Pai, H. [Variable Energy Cyclotron Centre, Kolkata (India); Madhavan, N.; Bala, I.; Gehlot, J.; Gurjar, R.K.; Jhingan, A.; Kumar, R.; Muralithar, S.; Nath, S.; Singh, R.P.; Varughese, T. [Inter University Acclerator Centre, New Delhi (India); Basu, K.; Bhattacharjee, S.S.; Ghugre, S.S.; Raut, R.; Sinha, A.K. [UGC-DAE-CSR Kolkata Centre, Kolkata (India); Palit, R. [Tata Institute of Fundamental Research, Department of Nuclear and Atomic Physics, Mumbai (India)

    2015-11-15

    A new high-spin isomer has been identified in {sup 195}Bi at the focal plane of the HYbrid Recoil mass Analyser (HYRA) used in the gas-filled mode. The fusion evaporation reactions {sup 169}Tm ({sup 30}Si, x n) {sup 193,} {sup 195}Bi were used with the beam energies on targets of 168 and 146MeV for 6n and 4n channels, respectively. The evaporation residues, separated from the fission fragments, and their decays were detected at the focal plane of HYRA using MWPC, Si-Pad and clover HPGe detectors. The half-life of the new isomer in {sup 195}Bi has been measured to be 1.6(1) μs. The configuration of the new isomer has been proposed and compared with the other isomers in this region. The Total Routhian Surface (TRS) calculations for the three-quasiparticle configurations corresponding to the new isomer suggest an oblate deformation for this isomeric state. The same calculations for different configurations in {sup 195}Bi and for the even-even {sup 194}Pb core indicate that the proton i{sub 13/2} orbital has a large shape driving effect towards oblate shape in these nuclei. (orig.)

  16. A new high-spin isomer in 195Bi

    Science.gov (United States)

    Roy, T.; Mukherjee, G.; Madhavan, N.; Rana, T. K.; Bhattacharya, Soumik; Asgar, Md. A.; Bala, I.; Basu, K.; Bhattacharjee, S. S.; Bhattacharya, C.; Bhattacharya, S.; Bhattacharyya, S.; Gehlot, J.; Ghugre, S. S.; Gurjar, R. K.; Jhingan, A.; Kumar, R.; Muralithar, S.; Nath, S.; Pai, H.; Palit, R.; Raut, R.; Singh, R. P.; Sinha, A. K.; Varughese, T.

    2015-11-01

    A new high-spin isomer has been identified in 195Bi at the focal plane of the HYbrid Recoil mass Analyser (HYRA) used in the gas-filled mode. The fusion evaporation reactions 169Tm (30Si, x n) 193, 195Bi were used with the beam energies on targets of 168 and 146MeV for 6n and 4n channels, respectively. The evaporation residues, separated from the fission fragments, and their decays were detected at the focal plane of HYRA using MWPC, Si-Pad and clover HPGe detectors. The half-life of the new isomer in 195Bi has been measured to be 1.6(1)μs. The configuration of the new isomer has been proposed and compared with the other isomers in this region. The Total Routhian Surface (TRS) calculations for the three-quasiparticle configurations corresponding to the new isomer suggest an oblate deformation for this isomeric state. The same calculations for different configurations in 195Bi and for the even-even 194Pb core indicate that the proton i 13/2 orbital has a large shape driving effect towards oblate shape in these nuclei.

  17. Induction of Chirality in Two-Dimensional Nanomaterials: Chiral 2D MoS2Nanostructures.

    Science.gov (United States)

    Purcell-Milton, Finn; McKenna, Robert; Brennan, Lorcan J; Cullen, Conor P; Guillemeney, Lilian; Tepliakov, Nikita V; Baimuratov, Anvar S; Rukhlenko, Ivan D; Perova, Tatiana S; Duesberg, Georg S; Baranov, Alexander V; Fedorov, Anatoly V; Gun'ko, Yurii K

    2018-02-27

    Two-dimensional (2D) nanomaterials have been intensively investigated due to their interesting properties and range of potential applications. Although most research has focused on graphene, atomic layered transition metal dichalcogenides (TMDs) and particularly MoS 2 have gathered much deserved attention recently. Here, we report the induction of chirality into 2D chiral nanomaterials by carrying out liquid exfoliation of MoS 2 in the presence of chiral ligands (cysteine and penicillamine) in water. This processing resulted in exfoliated chiral 2D MoS 2 nanosheets showing strong circular dichroism signals, which were far past the onset of the original chiral ligand signals. Using theoretical modeling, we demonstrated that the chiral nature of MoS 2 nanosheets is related to the presence of chiral ligands causing preferential folding of the MoS 2 sheets. There was an excellent match between the theoretically calculated and experimental spectra. We believe that, due to their high aspect ratio planar morphology, chiral 2D nanomaterials could offer great opportunities for the development of chiroptical sensors, materials, and devices for valleytronics and other potential applications. In addition, chirality plays a key role in many chemical and biological systems, with chiral molecules and materials critical for the further development of biopharmaceuticals and fine chemicals, and this research therefore should have a strong impact on relevant areas of science and technology such as nanobiotechnology, nanomedicine, and nanotoxicology.

  18. Synthesis and characterization of mixed ligand chiral nanoclusters

    KAUST Repository

    Guven, Zekiye P.

    2016-06-22

    Chiral mixed ligand silver nanoclusters were synthesized in the presence of a chiral and an achiral ligand. While the chiral ligand led mostly to the formation of nanoparticles, the presence of the achiral ligand drastically increased the yield of nanoclusters with enhanced chiral properties. © 2016 The Royal Society of Chemistry.

  19. Chirality controlled responsive self-assembled nanotubes in water

    NARCIS (Netherlands)

    van Dijken, D. J.; Stacko, P.; Stuart, M. C. A.; Browne, W. R.; Feringa, B. L.

    2017-01-01

    The concept of using chirality to dictate dimensions and to store chiral information in self-assembled nanotubes in a fully controlled manner is presented. We report a photoresponsive amphiphile that co-assembles with its chiral counterpart to form nanotubes and demonstrate how chirality can be used

  20. Effects of temperature on the astaxanthin productivity and light harvesting characteristics of the green alga Haematococcus pluvialis.

    Science.gov (United States)

    Giannelli, Luca; Yamada, Hiroyuki; Katsuda, Tomohisa; Yamaji, Hideki

    2015-03-01

    The green alga Haematococcus pluvialis, which accumulates astaxanthin at an optimal temperature of 20°C, was cultivated under temperatures of 20°C, 23.5°C, 27°C, and 30.5°C, in order to assess the effects on algal metabolism during the growth phase. The culture growth rate declined with above-optimal increases in temperature, and the final maximum cell concentration at 30.5°C reached only 35% of that attained at 20°C. On the contrary, the biomass productivity was increased under all the high-temperature conditions, probably reflecting the metabolism switch from cell duplication to energy accumulation that is typically observed in algal cultures subjected to environmental stress. Moreover, an increase in the light-harvesting capability of the alga was observed by means of the total pigment balance and the photosynthesis-intensity (PI) curve measured under the different cultivation conditions. Cultures kept at higher temperatures were able to better harvest and utilize the impinging light due to photo-acclimation. Finally, the differences in the astaxanthin metabolism were elucidated by subjecting the cultures to nitrogen starvation at 20°C and 27°C. In the culture at 27°C, a 1.4-fold increase in the astaxanthin productivity was observed when compared to that at 20°C, and the latter required almost two-fold more energy for the astaxanthin production compared with the 27°C culture. Copyright © 2014. Published by Elsevier B.V.

  1. Astaxanthin vs placebo on arterial stiffness, oxidative stress and inflammation in renal transplant patients (Xanthin: a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Robertson Iain K

    2008-12-01

    Full Text Available Abstract Background There is evidence that renal transplant recipients have accelerated atherosclerosis manifest by increased cardiovascular morbidity and mortality. The high incidence of atherosclerosis is, in part, related to increased arterial stiffness, vascular dysfunction, elevated oxidative stress and inflammation associated with immunosuppressive therapy. The dietary supplement astaxanthin has shown promise as an antioxidant and anti-inflammatory therapeutic agent in cardiovascular disease. The aim of this trial is to investigate the effects of astaxanthin supplementation on arterial stiffness, oxidative stress and inflammation in renal transplant patients. Method and Design This is a randomised, placebo controlled clinical trial. A total of 66 renal transplant recipients will be enrolled and allocated to receive either 12 mg/day of astaxanthin or an identical placebo for one-year. Patients will be stratified into four groups according to the type of immunosuppressant therapy they receive: 1 cyclosporine, 2 sirolimus, 3 tacrolimus or 4 prednisolone+/-azathioprine, mycophenolate mofetil or mycophenolate sodium. Primary outcome measures will be changes in 1 arterial stiffness measured by aortic pulse wave velocity (PWV, 2 oxidative stress assessed by plasma isoprostanes and 3 inflammation by plasma pentraxin 3. Secondary outcomes will include changes in vascular function assessed using the brachial artery reactivity (BAR technique, carotid artery intimal medial thickness (CIMT, augmentation index (AIx, left ventricular afterload and additional measures of oxidative stress and inflammation. Patients will undergo these measures at baseline, six and 12 months. Discussion The results of this study will help determine the efficacy of astaxanthin on vascular structure, oxidative stress and inflammation in renal transplant patients. This may lead to a larger intervention trial assessing cardiovascular morbidity and mortality. Trial Registration

  2. Effects of Dietary Supplementation with Astaxanthin on Histamine Induced Lesions in the Gizzard and Proventriculus of Broiler Chicks

    OpenAIRE

    Mi-hyang Ohh; Seongjin Kim; Sok Cheon Pak; Kew-mahn Chee

    2016-01-01

    Astaxanthin (ASX) is a xanthophyll pigment isolated from crustaceans and salmonids. Owing to its powerful antioxidant activity, ASX has been reported to have the potential to protect against gastric ulcers and a variety of other illnesses. Histamine (His) is a dietary factor that causes gastric erosion and ulceration in young chicks. In this study, we examined whether ASX had protective effects on dietary histamine-induced lesions in the gizzard and proventriculus of broiler chickens. Four ex...

  3. Chlorophylls, Symmetry, Chirality, and Photosynthesis

    Directory of Open Access Journals (Sweden)

    Mathias O. Senge

    2014-09-01

    Full Text Available Chlorophylls are a fundamental class of tetrapyrroles and function as the central reaction center, accessory and photoprotective pigments in photosynthesis. Their unique individual photochemical properties are a consequence of the tetrapyrrole macrocycle, the structural chemistry and coordination behavior of the phytochlorin system, and specific substituent pattern. They achieve their full potential in solar energy conversion by working in concert in highly complex, supramolecular structures such as the reaction centers and light-harvesting complexes of photobiology. The biochemical function of these structures depends on the controlled interplay of structural and functional principles of the apoprotein and pigment cofactors. Chlorophylls and bacteriochlorophylls are optically active molecules with several chiral centers, which are necessary for their natural biological function and the assembly of their supramolecular complexes. However, in many cases the exact role of chromophore stereochemistry in the biological context is unknown. This review gives an overview of chlorophyll research in terms of basic function, biosynthesis and their functional and structural role in photosynthesis. It highlights aspects of chirality and symmetry of chlorophylls to elicit further interest in their role in nature.

  4. Astaxanthin and papilioerythrinone in the skin of birds: a chromatic convergence of two metabolic routes with different precursors?

    Science.gov (United States)

    García-de Blas, Esther; Mateo, Rafael; Guzmán Bernardo, Francisco Javier; Rodríguez Martín-Doimeadios, Rosa Carmen; Alonso-Alvarez, Carlos

    2014-05-01

    Carotenoids are organic pigments involved in several important physiological functions and may serve as indicators of individual quality in animals. These pigments are only obtained by animals from the diet, but they can be later transformed into other carotenoids by specific enzymatic reactions. The diet of farm-reared and probably wild red-legged partridges ( Alectoris rufa) is mainly based on cereals that contain high levels of lutein and zeaxanthin. These two carotenoids are also predominant in internal tissues and blood of red-legged partridges. However, in their integuments, astaxanthin and papilioerythrinone (the last one identified in this work) are mainly present in their free form and esterified with fatty acids. According to available literature about carotenoid metabolism in animals, we propose that astaxanthin ( λ max = 478 nm) and papilioerythrinone ( λ max = 452-478 nm) are the result of a chromatic convergence of the transformation of dietary zeaxanthin and lutein, respectively. Moreover, the results obtained in this work provide the first identification by liquid chromatography coupled to accurate mass quadrupole time-of-flight mass spectrometer system of papilioerythrinone ( m/z 581.3989 [M + H]+) in the skin (i.e., not feathers) of a vertebrate. Astaxanthin and papilioerythrinone are very close in terms of chemical structure and coloration, and the combination of these two keto-carotenoids is responsible for the red color of the ornaments in red-legged partridges.

  5. Effect of dietary astaxanthin on free radical scavenging capacity and nitrite stress tolerance of postlarvae shrimp, Pleoticus muelleri.

    Science.gov (United States)

    Díaz, Ana Cristina; Velurtas, Susana María; Espino, María Laura; Fenucci, Jorge Lino

    2014-12-24

    The aim of this study was to investigate the effect of astaxanthin feed supplementation and environmental nitrite stress in postlarvae of Pleoticus muelleri (15 ± 0.004 mg initial weight) under culture conditions. Diets containing three levels of astaxanthin, 0 mg kg(-1) of diet (C0), 100 mg kg(-1) of diet (C(100)), and 300 mg kg(-1) of diet (C(300)), were used. Postlarvae fed with each diet were exposed to different concentrations of nitrite (NO(2)Na) (0-200 mg L(-1)). The 96 h median lethal concentration (LC50) values of nitrite N were 76.3, 89.7, and 157 mg L(-1) for shrimps fed to C0, C(100), and C(300). The scavenging properties were evaluated against the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical by electron resonance spectroscopy (EPR). For all feed treatments, the extracts exhibited strong DPPH scavenging activity; however, shrimp fed with C(100) and C(300) showed the greatest activity to quench DPPH (62 and 59%, respectively) with respect to C0 (43%). It can be concluded that astaxanthin acts as a protector of nitrite stress in P. muelleri.

  6. A sub-chronic toxicity evaluation of a natural astaxanthin-rich carotenoid extract of Paracoccus carotinifaciens in rats

    Directory of Open Access Journals (Sweden)

    Toyohisa Katsumata

    2014-01-01

    Full Text Available Astaxanthin is believed to be beneficial to human health because it possesses strong antioxidant properties. A natural astaxanthin-rich carotenoid extract (ARE was produced by a well-controlled fermentation of a natural bacteria Paracoccus carotinifaciens, followed by the extraction and enrichment of the final product comprising mixture of carotenoids that is predominantly astaxanthin. The aim of this study was to evaluate the sub-chronic toxicity of the ARE using 6 week old Sprague-Dawley SPF rats [Crl:CD(SD]. The test article was suspended in olive oil and administered daily to the rats by oral gavage for 13 weeks at doses of 0 (olive oil, 250, 500 or 1000 mg/kg/day. Each group consisted of 10 animals of each sex. No deaths occurred and no treatment-related changes were observed in the detailed clinical observations, manipulative tests, grip strength, motor activity, body weights, food consumption, ophthalmology, urinalysis, hematology, blood chemistry, organ weight, necropsy or histopathology. Dark-red feces were observed throughout the administration period in all treated groups due to excretion of the colored test article. Based on these results, it was concluded that the no observed adverse effect level (NOAEL for ARE was at least 1000 mg/kg/day for male and female rats, respectively.

  7. Oxidative Stress Regulation on Endothelial Cells by Hydrophilic Astaxanthin Complex: Chemical, Biological, and Molecular Antioxidant Activity Evaluation

    Directory of Open Access Journals (Sweden)

    M. Zuluaga

    2017-01-01

    Full Text Available An imbalance in the reactive oxygen species (ROS homeostasis is involved in the pathogenesis of oxidative stress-related diseases. Astaxanthin, a xanthophyll carotenoid with high antioxidant capacities, has been shown to prevent the first stages of oxidative stress. Here, we evaluate the antioxidant capacities of astaxanthin included within hydroxypropyl-beta-cyclodextrin (CD-A to directly and indirectly reduce the induced ROS production. First, chemical methods were used to corroborate the preservation of astaxanthin antioxidant abilities after inclusion. Next, antioxidant scavenging properties of CD-A to inhibit the cellular and mitochondrial ROS by reducing the disturbance in the redox state of the cell and the infiltration of lipid peroxidation radicals were evaluated. Finally, the activation of endogenous antioxidant PTEN/AKT, Nrf2/HO-1, and NQOI gene and protein expression supported the protective effect of CD-A complex on human endothelial cells under stress conditions. Moreover, a nontoxic effect on HUVEC was registered after CD-A complex supplementation. The results reported here illustrate the need to continue exploring the interesting properties of this hydrophilic antioxidant complex to assist endogenous systems to counteract the ROS impact on the induction of cellular oxidative stress state.

  8. A sub-chronic toxicity evaluation of a natural astaxanthin-rich carotenoid extract of Paracoccus carotinifaciens in rats.

    Science.gov (United States)

    Katsumata, Toyohisa; Ishibashi, Takashi; Kyle, David

    2014-01-01

    Astaxanthin is believed to be beneficial to human health because it possesses strong antioxidant properties. A natural astaxanthin-rich carotenoid extract (ARE) was produced by a well-controlled fermentation of a natural bacteria Paracoccus carotinifaciens, followed by the extraction and enrichment of the final product comprising mixture of carotenoids that is predominantly astaxanthin. The aim of this study was to evaluate the sub-chronic toxicity of the ARE using 6 week old Sprague-Dawley SPF rats [Crl:CD(SD)]. The test article was suspended in olive oil and administered daily to the rats by oral gavage for 13 weeks at doses of 0 (olive oil), 250, 500 or 1000 mg/kg/day. Each group consisted of 10 animals of each sex. No deaths occurred and no treatment-related changes were observed in the detailed clinical observations, manipulative tests, grip strength, motor activity, body weights, food consumption, ophthalmology, urinalysis, hematology, blood chemistry, organ weight, necropsy or histopathology. Dark-red feces were observed throughout the administration period in all treated groups due to excretion of the colored test article. Based on these results, it was concluded that the no observed adverse effect level (NOAEL) for ARE was at least 1000 mg/kg/day for male and female rats, respectively.

  9. Enhanced Chiral Discriminatory van der Waals Interactions Mediated by Chiral Surfaces

    Science.gov (United States)

    Barcellona, Pablo; Safari, Hassan; Salam, A.; Buhmann, Stefan Yoshi

    2017-05-01

    We predict a discriminatory interaction between a chiral molecule and an achiral molecule which is mediated by a chiral body. To achieve this, we generalize the van der Waals interaction potential between two ground-state molecules with electric, magnetic, and chiral response to nontrivial environments. The force is evaluated using second-order perturbation theory with an effective Hamiltonian. Chiral media enhance or reduce the free interaction via many-body interactions, making it possible to measure the chiral contributions to the van der Waals force with current technology. The van der Waals interaction is discriminatory with respect to enantiomers of different handedness and could be used to separate enantiomers. We also suggest a specific geometric configuration where the electric contribution to the van der Waals interaction is zero, making the chiral component the dominant effect.

  10. Enhanced Chiral Discriminatory van der Waals Interactions Mediated by Chiral Surfaces.

    Science.gov (United States)

    Barcellona, Pablo; Safari, Hassan; Salam, A; Buhmann, Stefan Yoshi

    2017-05-12

    We predict a discriminatory interaction between a chiral molecule and an achiral molecule which is mediated by a chiral body. To achieve this, we generalize the van der Waals interaction potential between two ground-state molecules with electric, magnetic, and chiral response to nontrivial environments. The force is evaluated using second-order perturbation theory with an effective Hamiltonian. Chiral media enhance or reduce the free interaction via many-body interactions, making it possible to measure the chiral contributions to the van der Waals force with current technology. The van der Waals interaction is discriminatory with respect to enantiomers of different handedness and could be used to separate enantiomers. We also suggest a specific geometric configuration where the electric contribution to the van der Waals interaction is zero, making the chiral component the dominant effect.

  11. Enhancing circular dichroism by super chiral hot spots from a chiral metasurface with apexes

    Science.gov (United States)

    Wang, Zeng; Teh, Bing Hong; Wang, Yue; Adamo, Giorgio; Teng, Jinghua; Sun, Handong

    2017-05-01

    Manipulating light spin (or circular polarization) is an important research field and may find broad applications from sensors, display technology, to quantum computing and communication. To this end, planar metasurfaces with larger circular dichroism are strongly demanded. However, current planar chiral metasurface structures suffer from either fabrication challenge, especially from near-infrared to visible spectrum, or insufficient circular dichroism. Here, we report a chiral metasurface composed of achiral nanoholes which allow for precisely creating apexes in the designed structure. Our investigation indicates that the apexes act as super chiral hot spots and enable the highly concentrated near-field optical chirality leading to a remarkable enhancement of circular dichroism in the far-field. A 4-fold enhancement of the circular dichroism and a strong optical activity of ˜15 degrees have been experimentally achieved. Besides the enhanced chirality, our design genuinely overcomes the nanofabrication challenge faced in existing planar chiral metasurfaces.

  12. Potential-driven chirality manifestations and impressive enantioselectivity by inherently chiral electroactive organic films.

    Science.gov (United States)

    Sannicolò, Francesco; Arnaboldi, Serena; Benincori, Tiziana; Bonometti, Valentina; Cirilli, Roberto; Dunsch, Lothar; Kutner, Włodzimierz; Longhi, Giovanna; Mussini, Patrizia R; Panigati, Monica; Pierini, Marco; Rizzo, Simona

    2014-03-03

    The typical design of chiral electroactive materials involves attaching chiral pendants to an electroactive polyconjugated backbone and generally results in modest chirality manifestations. Discussed herein are electroactive chiral poly-heterocycles, where chirality is not external to the electroactive backbone but inherent to it, and results from a torsion generated by the periodic presence of atropisomeric, conjugatively active biheteroaromatic scaffolds, (3,3'-bithianaphthene). As the stereogenic element coincides with the electroactive one, films of impressive chiroptical activity and outstanding enantiodiscrimination properties are obtained. Moreover, chirality manifestations can be finely and reversibly tuned by the electric potential, as progressive injection of holes forces the two thianaphthene rings to co-planarize to favor delocalization. Such deformations, revealed by CD spectroelectrochemistry, are elastic and reversible, thus suggesting a breathing system. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Theoretical Study of the Diastereofacial Isomers of Aldrin and Dieldrin

    Directory of Open Access Journals (Sweden)

    Zoran Zdravkovski

    2006-02-01

    Full Text Available The Diels-Alder reaction of hexachlorocyclopentadiene with norbornadiene givesaldrin but theoretically three other diastereofacial isomers are possible. On oxidation theseisomers can generate eight adducts one of which is known as dieldrin. All these, as well asthe corresponding reactions with hexafluorocyclopenadiene were studied by semiempirical(AM1 and PM3 and hybrid density functional (B3LYP methods. Besides the energy levels,the transition states were calculated for the reactions leading to the diastereofacial isomers ofaldrin, which indicate that aldrin is the favored product of the reaction both fromthermodynamic and kinetic point of view.

  14. Static and dynamic first hyperpolarizabilities of azo-enaminone isomers

    Science.gov (United States)

    Fonseca, T. L.; Castro, M. A.; de Oliveira, H. C. B.; Cunha, S.

    2007-07-01

    The linear polarizabilities and first hyperpolarizabilities of two geometrical isomers ( Z, E) of donor-acceptor azo-enaminones have been calculated, taking into account frequency dispersion effects, through CPHF method. Static results were also obtained at the MP2 level and correlated dynamic values were estimated using the multiplicative correction scheme. Our results show that the diagonal component of the first hypepolarizability of E isomers is enhanced with increasing donor strength. Dispersion effects have a marked influence for the standard frequencies considered here ( ω = 0.0239 and 0.0428 a.u), specially for second harmonic generation.

  15. Model for chiral symmetry breaking in QCD

    Energy Technology Data Exchange (ETDEWEB)

    Govaerts, J.; Weyers, J.; Mandula, J.E.

    1984-04-30

    A recently proposed model for dynamical breaking of chiral symmetry in QCD is extended and developed for the calculation of pion and chiral symmetry breaking parameters. The pion is explicitly realized as a massless Goldstone boson and as a bound state of the constituent quarks. We compute, in the limit of exact chiral symmetry, Msub(Q), the constituent quark mass, fsub(..pi..), the pion decay coupling, , the constituent quark loop density, ..mu..sub(..pi..)/sup 2//msub(q), the ratio of the Goldstone boson mass squared to the bare quark mass, and sub(..pi..), the pion electromagnetic charge radius squared.

  16. Partial restoration of chiral symmetry inside hadrons

    Energy Technology Data Exchange (ETDEWEB)

    Iritani, Takumi [Yukawa Institute for Theoretical Physics (YITP) (Japan); Cossu, Guido [High Energy Accelerator Research Organization (KEK) (Japan); Hashimoto, Shoji [High Energy Accelerator Research Organization (KEK) (Japan); School of High Energy Accelerator Science, The Graduate University for Advanced Studies (Sokendai) (Japan)

    2016-01-22

    We investigate the spatial distribution of the chiral condensate around static color sources for both quark-antiquark and three-quark systems. In the QCD vacuum a tube-like structure of chromo fields appears between color sources, which leads to a linearly confining potential. We show that the magnitude of the condensate is reduced inside the flux-tube, which suggests that chiral symmetry is partially restored inside the hadrons. By using a static baryon source in a periodic box as a model of the nuclear matter, we estimate the restoration of chiral symmetry with finite baryon number density.

  17. Partial restoration of chiral symmetry inside hadrons

    Science.gov (United States)

    Iritani, Takumi; Cossu, Guido; Hashimoto, Shoji

    2016-01-01

    We investigate the spatial distribution of the chiral condensate around static color sources for both quark-antiquark and three-quark systems. In the QCD vacuum a tube-like structure of chromo fields appears between color sources, which leads to a linearly confining potential. We show that the magnitude of the condensate is reduced inside the flux-tube, which suggests that chiral symmetry is partially restored inside the hadrons. By using a static baryon source in a periodic box as a model of the nuclear matter, we estimate the restoration of chiral symmetry with finite baryon number density.

  18. Enhanced Chiral Recognition by Cyclodextrin Dimers

    Directory of Open Access Journals (Sweden)

    Bart Jan Ravoo

    2011-07-01

    Full Text Available In this article we investigate the effect of multivalency in chiral recognition. To this end, we measured the host-guest interaction of a β-cyclodextrin dimer with divalent chiral guests. We report the synthesis of carbohydrate-based water soluble chiral guests functionalized with two borneol, menthol, or isopinocampheol units in either (+ or (– configuration. We determined the interaction of these divalent guests with a β-cyclodextrin dimer using isothermal titration calorimetry. It was found that—in spite of a highly unfavorable conformation—the cyclodextrin dimer binds to guest dimers with an increased enantioselectivity, which clearly reflects the effect of multivalency.

  19. Exploring chiral dynamics with overlap fermions

    CERN Document Server

    Fukaya, Hidenori

    2010-01-01

    This talk presents a lattice study of spontaneous chiral symmetry breaking performed by the JLQCD and TWQCD collaborations with dynamical overlap fermions. Our lattice configurations are generated in a fixed topological sector. Since finite volume effects, partly due to the fixed global topology, are mainly induced by pion fields, the dependence on the lattice volume, topological charge and quark masses can be analytically predicted using chiral perturbation theory (ChPT). We find a good agreement of Dirac operator spectrum calculated on the lattice with the ChPT prediction including its finite size scalings, through which the chiral condensate is determined with good accuracy.

  20. N = 3 chiral supergravity compatible with the reality condition and higher N chiral Lagrangian density

    OpenAIRE

    Tsuda, Motomu

    2000-01-01

    We obtain N = 3 chiral supergravity (SUGRA) compatible with the reality condition by applying the prescription of constructing the chiral Lagrangian density from the usual SUGRA. The $N = 3$ chiral Lagrangian density in first-order form, which leads to the Ashtekar's canonical formulation, is determined so that it reproduces the second-order Lagrangian density of the usual SUGRA especially by adding appropriate four-fermion contact terms. We show that the four-fermion contact terms added in t...

  1. Review of aqueous chiral electrokinetic chromatography (EKC) with an emphasis on chiral microemulsion EKC.

    Science.gov (United States)

    Kahle, Kimberly A; Foley, Joe P

    2007-08-01

    The separation of enantiomers using electrokinetic chromatography (EKC) with chiral microemulsions is comprehensively reviewed through December 1, 2006. Aqueous chiral EKC separations based on other pseudostationary phases such as micelles and vesicles or on other chiral selectors such as CDs, crown ethers, glycopeptides, ligand exchange moeities are also reviewed from both mechanistic and applications perspective for the period of January 2005 to December 1, 2006.

  2. Effect of red cyst cell inoculation and iron(II) supplementation on autotrophic astaxanthin production by Haematococcus pluvialis under outdoor summer conditions.

    Science.gov (United States)

    Hong, Min-Eui; Choi, Yoon Young; Sim, Sang Jun

    2016-01-20

    The negative effect of heat stress on the autotrophic astaxanthin production by Haematococcus pluvialis has been observed during outdoor culture in summer. Under the summer conditions, the proliferation of vegetative cells was highly halted in the green stage and the inducibility in the biosynthesis of astaxanthin was partly hindered in the red stage. Herein, under outdoor summer conditions in which variations of the diurnal temperature occur, heat-stress-driven inefficient vegetative growth of H. pluvialis was highly improved by inoculating the red cyst cells; thereby, maintaining relatively moderate intracellular carotenoid levels in the green stage. Subsequently, a remarkably enhanced astaxanthin titer was successfully obtained by supplementing 50 μM iron(II) to induce the heat stress-driven Haber-Weiss reaction in the red stage. As a result, the productivity of astaxanthin in the cells cultured under summer temperature conditions (23.4-33.5 °C) using the two methods of red cell (cyst) inoculation and the iron(Fe(2+)) supplementation was increased by 147% up to 5.53 mg/L day compared with that of the cells cultured under spring temperature conditions (17.5-27.3 °C). Our technical solutions will definitely improve the annual natural astaxanthin productivity in H. pluvialis in locations confronted by hot summer weather, particularly in large-scale closed photobioreactor systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Thermal chiral vortical and magnetic waves: New excitation modes in chiral fluids

    Science.gov (United States)

    Kalaydzhyan, Tigran; Murchikova, Elena

    2017-06-01

    In certain circumstances, chiral (parity-violating) medium can be described hydrodynamically as a chiral fluid with microscopic quantum anomalies. Possible examples of such systems include strongly coupled quark-gluon plasma, liquid helium 3He-A, neutron stars and the Early Universe. We study first-order hydrodynamics of a chiral fluid on a vortex background and in an external magnetic field. We show that there are two previously undiscovered modes describing heat waves propagating along the vortex and magnetic field. We call them the Thermal Chiral Vortical Wave and Thermal Chiral Magnetic Wave. We also identify known gapless excitations of density (chiral vortical and chiral magnetic waves) and transverse velocity (chiral Alfvén wave). We demonstrate that the velocity of the chiral vortical wave is zero, when the full hydrodynamic framework is applied, and hence the wave is absent and the excitation reduces to the charge diffusion mode. We also comment on the frame-dependent contributions to the obtained propagation velocities.

  4. Thermal chiral vortical and magnetic waves: New excitation modes in chiral fluids

    Energy Technology Data Exchange (ETDEWEB)

    Kalaydzhyan, Tigran, E-mail: tigran@caltech.edu [Department of Physics, University of Illinois, 845 W Taylor Street, Chicago, IL 60607 (United States); Jet Propulsion Laboratory, 4800 Oak Grove Dr, M/S 298, Pasadena, CA 91109 (United States); Murchikova, Elena [TAPIR, California Institute of Technology, MC 350-17, Pasadena, CA 91125 (United States)

    2017-06-15

    In certain circumstances, chiral (parity-violating) medium can be described hydrodynamically as a chiral fluid with microscopic quantum anomalies. Possible examples of such systems include strongly coupled quark–gluon plasma, liquid helium {sup 3}He-A, neutron stars and the Early Universe. We study first-order hydrodynamics of a chiral fluid on a vortex background and in an external magnetic field. We show that there are two previously undiscovered modes describing heat waves propagating along the vortex and magnetic field. We call them the Thermal Chiral Vortical Wave and Thermal Chiral Magnetic Wave. We also identify known gapless excitations of density (chiral vortical and chiral magnetic waves) and transverse velocity (chiral Alfvén wave). We demonstrate that the velocity of the chiral vortical wave is zero, when the full hydrodynamic framework is applied, and hence the wave is absent and the excitation reduces to the charge diffusion mode. We also comment on the frame-dependent contributions to the obtained propagation velocities.

  5. Improved Chiral Separation of (R,S-Goitrin by SFC: An Application in Traditional Chinese Medicine

    Directory of Open Access Journals (Sweden)

    Lixing Nie

    2016-01-01

    Full Text Available Like chemical drugs, research and development of herbal medicine also have a need to resolve enantiomers. To help illustrating the antiviral bioactivity of Isatidis Radix, a widely used traditional Chinese medicine (TCM, supercritical fluid chromatography (SFC was used for analytical and preparative separation of (R,S-goitrin, which was reported as the active ingredient of the herbal. Improved resolution was achieved on Chiralpak IC column, using acetonitrile as the organic modifier, representing a tenfold increase in speed, compared to the previous normal phase HPLC (NPLC method. The newly developed chromatographic method was validated in terms of linearity, precision, limit of detection (LOD, and limit of quantitation (LOQ. Scale-up purification of (R-goitrin and (S-goitrin was performed on a preparative column with >90% total recovery. The absolute stereochemical assignment of the purified isomers was determined through optical rotation study. This attempt explored SFC’s application in chiral research of traditional Chinese medicine.

  6. Effect of rice-straw biochar on selective biodegradation of nonylphenols in isomer specificity.

    Science.gov (United States)

    Yao, Lingdan; Wang, Lixiao; Cheng, Guanghuan; Huang, Qian; Hu, Baolan; Lu, Jingrang; Lou, Liping

    2017-09-01

    In a previous study, we found that rice-straw biochar degraded and removed hydrophobic organic contaminants (HOCs) through coupled adsorption-biodegradation. However, few studies have determined whether biochar affects HOC isomer degradation and isomer-selective biodegradation or whether biochar can alter HOC isomer features, resulting in changes to HOC isomer residues in water environments. In this study, the effects of biochar at two dosages (0.001 and 0.01 g) on the biodegradation of ten isomers of a typical xenoestrogen of nonylphenol (NP) were evaluated. The results revealed that there were no effects of biochar on the adsorption of NP isomers. However, biochar addition affected the biodegradation of a specific isomer without altering the features of the NP isomers. The treatment of NP isomers with Pseudoxanthomonas sp. yielded degradation ratios ranging from 60.7 to 100%. At 0.001 g biochar treatment, the degradation of eight NP isomers was enhanced (except for NP194 and NP193a+b) due to their bulky structures. The degradation of the ten NP isomers was inhibited when 0.01 g biochar was added. These findings characterized the effects of biochar on NP isomer contaminants and provided basic information for the application of biochar for the remediation of NP isomer contaminants.

  7. Chiral extrapolations for nucleon electric charge radii

    CERN Document Server

    Hall, J M M; Young, R D

    2013-01-01

    Lattice simulations for the electromagnetic form factors of the nucleon yield insights into the internal structure of hadrons. The logarithmic divergence of the charge radius in the chiral limit poses an interesting challenge in achieving reliable predictions from finite-volume lattice simulations. Recent results near the physical pion mass are examined in order to confront the issue of how the chiral regime is approached. The electric charge radius of the nucleon presents a forum for achieving consistent finite-volume corrections. Newly-developed techniques within the framework of chiral effective field theory are used to achieve a robust extrapolation of the electric charge radius to the physical pion mass, and to infinite volume. The chiral extrapolations exhibit considerable finite-volume dependence; lattice box sizes of L > 7 fm are required in order to achieve a direct lattice simulation result within 2% of the infinite-volume value at the physical point. Predictions of the volume-dependence are provide...

  8. Chirality and angular momentum in optical radiation

    CERN Document Server

    Coles, Matt M

    2012-01-01

    This paper develops, in precise quantum electrodynamic terms, photonic attributes of the "optical chirality density", one of several measures long known to be conserved quantities for a vacuum electromagnetic field. The analysis lends insights into some recent interpretations of chiroptical experiments, in which this measure, and an associated chirality flux, have been treated as representing physically distinctive "superchiral" phenomena. In the fully quantized formalism the chirality density is promoted to operator status, whose exploration with reference to an arbitrary polarization basis reveals relationships to optical angular momentum and helicity operators. Analyzing multi-mode beams with complex wave-front structures, notably Laguerre-Gaussian modes, affords a deeper understanding of the interplay between optical chirality and optical angular momentum. By developing theory with due cognizance of the photonic character of light, it emerges that only the spin angular momentum of light is engaged in such...

  9. Odd viscosity in chiral active fluids.

    Science.gov (United States)

    Banerjee, Debarghya; Souslov, Anton; Abanov, Alexander G; Vitelli, Vincenzo

    2017-11-17

    We study the hydrodynamics of fluids composed of self-spinning objects such as chiral grains or colloidal particles subject to torques. These chiral active fluids break both parity and time-reversal symmetries in their non-equilibrium steady states. As a result, the constitutive relations of chiral active media display a dissipationless linear-response coefficient called odd (or equivalently, Hall) viscosity. This odd viscosity does not lead to energy dissipation, but gives rise to a flow perpendicular to applied pressure. We show how odd viscosity arises from non-linear equations of hydrodynamics with rotational degrees of freedom, once linearized around a non-equilibrium steady state characterized by large spinning speeds. Next, we explore odd viscosity in compressible fluids and suggest how our findings can be tested in the context of shock propagation experiments. Finally, we show how odd viscosity in weakly compressible chiral active fluids can lead to density and pressure excess within vortex cores.

  10. Organometallic chemistry of chiral diphosphazane ligands ...

    Indian Academy of Sciences (India)

    Unknown

    Organometallic chemistry of chiral diphosphazane ligands: Synthesis and structural characterisation. KANNAN RAGHURAMAN, SWADHIN K MANDAL,. T S VENKATAKRISHNAN, SETHARAMPATTU S. KRISHNAMURTHY* and MUNIRATHINAM NETHAJI. Department of Inorganic and Physical Chemistry, Indian Institute of ...

  11. Controlling and imaging chiral spin textures

    Science.gov (United States)

    Chen, Gong

    Chirality in magnetic materials is fundamentally interesting and holds potential for logic and memory applications. Using spin-polarized low-energy electron microscopy at National Center for Electron Microscopy, we recently observed chiral domain walls in thin films. We developed ways to tailor the Dzyaloshinskii-Moriya interaction, which drives the chirality, by interface engineering and by forming ternary superlattices. We find that spin-textures can be switched between left-handed, right-handed, cycloidal, helical and mixed domain wall structures by controlling uniaxial strain in magnetic films. We also demonstrate an experimental approach to stabilize skyrmions in magnetic multilayers without external magnetic field. These results exemplify the rich physics of chirality associated with interfaces of magnetic materials

  12. Chiral Spin Pairing in Helical Magnets

    Science.gov (United States)

    Onoda, Shigeki; Nagaosa, Naoto

    2007-07-01

    A concept of chiral spin pairing is introduced to describe a vector-chiral liquid-crystal order in frustrated spin systems. It is found that the chiral spin pairing is induced by the coupling to phonons through the Dzyaloshinskii-Moriya interaction and the four-spin exchange interaction of the Coulomb origin under the edge-sharing network of magnetic and ligand ions. This produces two successive second-order phase transitions upon cooling: an O(2) chiral spin nematic, i.e., spin cholesteric, order appears with an either parity, and then the O(2) symmetry is broken to yield a helical magnetic order. Possible candidate materials are also discussed as new multiferroic systems.

  13. Light front distribution of the chiral condensate

    National Research Council Canada - National Science Library

    Chang, Lei; Roberts, Craig D; Schmidt, Sebastian M

    2013-01-01

    The pseudoscalar projection of the pionE1/4s Poincare-covariant Bethe-Salpeter amplitude onto the light-front may be understood to provide the probability distribution of the chiral condensate within the pion...

  14. Flexible metal–organic supramolecular isomers for gas separation

    Energy Technology Data Exchange (ETDEWEB)

    Motkuri, Radha K.; Tian, Jian; Thallapally, Praveen K.; Fernandez, Carlos A.; Dalgarno, Scott J.; Warren, John E.; McGrail, B. Peter; Atwood, Jerry L.

    2010-01-01

    Here in we report three porous metal-organic supramolecular isomers (PtS, Diamondoid and Lonsdaleite networks) generated from a single building block (tetrakis[4-(carboxyphenyl)oxamethyl]methane, 1), with the differences in solid-state packing, amount of gas uptake and selectivity towards other gases and so on

  15. "Star" morphologies of charged nanodrops comprised of conformational isomers.

    Science.gov (United States)

    In Oh, Myong; Paliy, Maxim; Consta, Styliani

    2018-01-14

    We study the spatial distribution of conformational isomers surrounding a central macroion in a charged droplet with linear dimensions in the nanometer range. Dimethyl carbonate and formic acid are selected as typical solvents that undergo isomerization and a charged buckyball (C60) is selected as a representative example of a macroion. The study is performed by atomistic molecular dynamics simulations. We find that when the charge of the buckyball is above a threshold value, it induces the formation of concentric shells of different conformational isomers surrounding the macroion. The presence of layers with different dielectric properties necessitates the use of different state equations for the solvent polarization in each layer. We find that at a high charge state of the buckyball, the nearest layer to the macroion comprises the conformers with the highest dipole moment. The interface of the outer layers of conformers is characterized by "ray"-forming structures of the higher dielectric constant isomers penetrating into the layer of the lowest dielectric constant isomers. For high values of the solvent dielectric constant, the charged droplet acquires a "star"-like global shape. We demonstrate that these distinct droplet structures are a manifestation of charge-induced instability. We describe this simulation-based phenomenology by an analytical theory that supports this conclusion. The findings suggest new experimental research venues that may explore the reactivity and assembly of molecules within regions of different dielectric properties in droplets.

  16. A study of the origin of chloramphenicol isomers in honey

    NARCIS (Netherlands)

    Yanovych, Dmytro; Berendsen, Bjorn; Zasadna, Zvenyslava; Rydchuk, Mariana; Czymai, Tobias

    2017-01-01

    Due to the unexpected detection of chloramphenicol isomer residues in honey, we have studied the hypothesis of unauthorized or unintended use of unregistered veterinary drug preparations. First, we have investigated honey samples in which a discrepancy was observed between the results of the

  17. Shape Isomer in 236U Populated by Thermal Neutron Capture

    DEFF Research Database (Denmark)

    Andersen, Verner; Christensen, Carl Jørgen; Borggreen, J.

    1976-01-01

    The 116 ns shape isomer in 236U was populated by thermal neutron capture. Conversion electrons and X-rays were detected simultaneously in delayed coincidence with fission. The ratio of delayed to prompt fission was measured with the result, σIIf/σf = (1.0±0.2) × 10−5. A branching of the isomeric...

  18. Biocatalytic Synthesis of Chiral Pharmaceutical Intermediates

    Directory of Open Access Journals (Sweden)

    Ramesh N. Patel

    2004-01-01

    Full Text Available The production of single enantiomers of drug intermediates has become increasingly important in the pharmaceutical industry. Chiral intermediates and fine chemicals are in high demand from both the pharmaceutical and agrochemical industries for the preparation of bulk drug substances and agricultural products. The enormous potential of microorganisms and enzymes for the transformation of synthetic chemicals with high chemo-, regio- and enantioselectivities has been demonstrated. In this article, biocatalytic processes are described for the synthesis of chiral pharmaceutical intermediates.

  19. Chiral Plasmonic Nanostructures on Achiral Nanopillars

    Science.gov (United States)

    2013-10-10

    substrates via hydrothermal synthesis33 (Figure 1a). The first Au layer is then deposited on the ZnO nanopillars. Note that the substrate is inclined...Nano Lett. 2013, 13, 5277−52835279 7 optical extinction of ZnO nanopillars (Figure 3b). ZnO nanopillars and NPs grown by hydrothermal methods do not...generates chiral absorption of the achiral ZnO nanopillars. Similar phenomena have been observed for achiral nano- particles when chiral organic

  20. Lattice quantum chromodynamics with approximately chiral fermions

    Energy Technology Data Exchange (ETDEWEB)

    Hierl, Dieter

    2008-05-15

    In this work we present Lattice QCD results obtained by approximately chiral fermions. We use the CI fermions in the quenched approximation to investigate the excited baryon spectrum and to search for the {theta}{sup +} pentaquark on the lattice. Furthermore we developed an algorithm for dynamical simulations using the FP action. Using FP fermions we calculate some LECs of chiral perturbation theory applying the epsilon expansion. (orig.)

  1. Switching chiral solitons for algebraic operation of topological quaternary digits

    Science.gov (United States)

    Kim, Tae-Hwan; Cheon, Sangmo; Yeom, Han Woong

    2017-02-01

    Chiral objects can be found throughout nature; in condensed matter chiral objects are often excited states protected by a system's topology. The use of chiral topological excitations to carry information has been demonstrated, where the information is robust against external perturbations. For instance, reading, writing, and transfer of binary information have been demonstrated with chiral topological excitations in magnetic systems, skyrmions, for spintronic devices. The next step is logic or algebraic operations of such topological bits. Here, we show experimentally the switching between chiral topological excitations or chiral solitons of different chirality in a one-dimensional electronic system with Z4 topological symmetry. We found that a fast-moving achiral soliton merges with chiral solitons to switch their handedness. This can lead to the realization of algebraic operation of Z4 topological charges. Chiral solitons could be a platform for storage and operation of robust topological multi-digit information.

  2. Analysis of rainbow scattering by a chiral sphere.

    Science.gov (United States)

    Shang, Qing-Chao; Wu, Zhen-Sen; Qu, Tan; Li, Zheng-Jun; Bai, Lu; Gong, Lei

    2013-09-23

    Based on the scattering theory of a chiral sphere, rainbow phenomenon of a chiral sphere is numerically analyzed in this paper. For chiral spheres illuminated by a linearly polarized wave, there are three first-order rainbows, with whose rainbow angles varying with the chirality parameter. The spectrum of each rainbow structure is presented and the ripple frequencies are found associated with the size and refractive indices of the chiral sphere. Only two rainbow structures remain when the chiral sphere is illuminated by a circularly polarized plane wave. Finally, the rainbows of chiral spheres with slight chirality parameters are found appearing alternately in E-plane and H-plane with the variation of the chirality.

  3. Symmetries of Ginsparg-Wilson chiral fermions

    Science.gov (United States)

    Mandula, Jeffrey E.

    2009-10-01

    The group structure of the variant chiral symmetry discovered by Lüscher in the Ginsparg-Wilson description of lattice chiral fermions is analyzed. It is shown that the group contains an infinite number of linearly independent symmetry generators, and the Lie algebra is given explicitly. CP is an automorphism of this extended chiral group, and the CP transformation properties of the symmetry generators are found. The group has an infinite-parameter invariant subgroup, and the factor group, whose elements are its cosets, is isomorphic to the continuum chiral symmetry group. Features of the currents associated with these symmetries are discussed, including the fact that some different, noncommuting symmetry generators lead to the same Noether current. These are universal features of lattice chiral fermions based on the Ginsparg-Wilson relation; they occur in the overlap, domain-wall, and perfect-action formulations. In a solvable example, free overlap fermions, these noncanonical elements of lattice chiral symmetry are related to complex energy singularities that violate reflection positivity and impede continuation to Minkowski space.

  4. Enantioselective separation on chiral Au nanoparticles.

    Science.gov (United States)

    Shukla, Nisha; Bartel, Melissa A; Gellman, Andrew J

    2010-06-30

    The surfaces of chemically synthesized Au nanoparticles have been modified with d- or l-cysteine to render them chiral and enantioselective for adsorption of chiral molecules. Their enantioselective interaction with chiral compounds has been probed by optical rotation measurements during exposure to enantiomerically pure and racemic propylene oxide. The ability of optical rotation to detect enantiospecific adsorption arises from the fact that the specific rotation of polarized light by (R)- and (S)-propylene oxide is enhanced by interaction with Au nanoparticles. This effect is related to previous observations of enhanced circular dichroism by Au nanoparticles modified by chiral adsorbates. More importantly, chiral Au nanoparticles modified with either d- or l-cysteine selectively adsorb one enantiomer of propylene oxide from a solution of racemic propylene oxide, thus leaving an enantiomeric excess in the solution phase. Au nanoparticles modified with l-cysteine (d-cysteine) selectively adsorb the (R)-propylene oxide ((S)-propylene oxide). A simple model has been developed that allows extraction of the enantiospecific equilibrium constants for (R)- and (S)-propylene oxide adsorption on the chiral Au nanoparticles.

  5. Synthesis of chiral amino epoxyaziridines: useful intermediates for the preparation of chiral trisubstituted piperidines.

    Science.gov (United States)

    Concellón, José M; Riego, Estela; Rivero, Ignacio A; Ochoa, Adrián

    2004-09-17

    Chiral aminoalkyl epoxyaziridine 1 is synthesized in high yield and diastereoselectivity from L-serine. Ring opening of epoxyaziridine 1 with primary amines is carried out with total chemo- and regioselectivity, affording chiral polyfunctionalized piperidines 8. The structure of these trisubstituted piperidines is established by NMR studies.

  6. Chiral polymerization in open systems from chiral-selective reaction rates.

    Science.gov (United States)

    Gleiser, Marcelo; Nelson, Bradley J; Walker, Sara Imari

    2012-08-01

    We investigate the possibility that prebiotic homochirality can be achieved exclusively through chiral-selective reaction rate parameters without any other explicit mechanism for chiral bias. Specifically, we examine an open network of polymerization reactions, where the reaction rates can have chiral-selective values. The reactions are neither autocatalytic nor do they contain explicit enantiomeric cross-inhibition terms. We are thus investigating how rare a set of chiral-selective reaction rates needs to be in order to generate a reasonable amount of chiral bias. We quantify our results adopting a statistical approach: varying both the mean value and the rms dispersion of the relevant reaction rates, we show that moderate to high levels of chiral excess can be achieved with fairly small chiral bias, below 10%. Considering the various unknowns related to prebiotic chemical networks in early Earth and the dependence of reaction rates to environmental properties such as temperature and pressure variations, we argue that homochirality could have been achieved from moderate amounts of chiral selectivity in the reaction rates.

  7. Supercritical carbon dioxide extraction of astaxanthin from Haematococcus pluvialis with vegetable oils as co-solvent.

    Science.gov (United States)

    Krichnavaruk, Sontaya; Shotipruk, Artiwan; Goto, Motonobu; Pavasant, Prasert

    2008-09-01

    Soybean oil and olive oil were investigated as continuous co-solvents for supercritical carbon dioxide (SC-CO(2)) extraction of astaxanthin from Haematococcus pluvialis. Without co-solvents, only 25.40+/-0.79% efficiency was achieved with SC-CO(2) extraction at 70 degrees C and 40 MPa at a continuous flow rate of 3 mL min(-1) for 5h. In the presence of soybean oil or olive oil as a co-solvent, the extraction efficiency was enhanced, with the most appropriate level of soybean oil in the solvent mixture being 10% by volume. At this concentration and the above extraction conditions, the highest extraction efficiency of 36.36+/-0.79% was obtained for soybean oil, a 30% increase in extraction efficiency compared with SC-CO(2) extraction without soybean oil, whereas the 10% olive oil increased the extraction efficiency further to 51.03+/-1.08%, which was comparable to that obtained using ethanol as co-solvent.

  8. Astaxanthin from psychrotrophic Sphingomonas faeni exhibits antagonism against food-spoilage bacteria at low temperatures.

    Science.gov (United States)

    Mageswari, Anbazhagan; Subramanian, Parthiban; Srinivasan, Ramachandran; Karthikeyan, Sivashanmugam; Gothandam, Kodiveri Muthukaliannan

    2015-10-01

    Food production and processing industry holds a perpetual relationship with microorganisms and their by-products. In the present study, we aimed to identify beneficial cold-adapted bacteria devoid of any food spoilage properties and study their antagonism against common food-borne pathogens at low temperature conditions. Ten isolates were obtained on selective isolation at 5 °C, which were spread across genera Pseudomonas, Sphingomonas, Psychrobacter, Leuconostoc, Rhodococcus, and Arthrobacter. Methanol extracts of strains were found to contain several bioactive metabolites. Among the studied isolates, methanol extracts of S. faeni ISY and Rhodococcus fascians CS4 were found to show antagonism against growth of Escherichia coli, Proteus mirabilis, Enterobacter aerogenes, Listeria monocytogenes and Vibrio fischeri at refrigeration temperatures. Characterization of the abundant yellow pigment in methanol extracts of S. faeni ISY through UV-Vis spectrophotometry, high performance liquid chromatography (HPLC) and mass spectrometry (LC-MS) revealed the presence of astaxanthin, which, owing to its presence in very large amounts and evidenced to be responsible for antagonistic activity of the solvent extract. Copyright © 2015 Elsevier GmbH. All rights reserved.

  9. Protective effects of Haematococcus astaxanthin on oxidative stress in healthy smokers.

    Science.gov (United States)

    Kim, Ji Hae; Chang, Min Jung; Choi, Hye Duck; Youn, Yeo-Kyu; Kim, Jung Tae; Oh, Jung Mi; Shin, Wan Gyoon

    2011-11-01

    Free radicals induced by cigarette smoking have been strongly linked to increased oxidative stress in vivo, contributing to the pathobiology of various diseases. This study was performed to investigate the effects of Haematococcus astaxanthin (ASX), which has been known to be a potent antioxidant, on oxidative stress in smokers. Thirty-nine heavy smokers (≥20 cigarettes/day) and 39 non-smokers were enrolled in this study. Smokers were randomly divided into three dosage groups to receive ASX at doses of 5, 20, or 40 mg (n=13, each) once daily for 3 weeks. Oxidative stress biomarkers such as malondialdehyde, isoprostane, superoxide dismutase, and total antioxidant capacity, and ASX levels in plasma were measured at baseline and after 1, 2, and 3 weeks of treatment. Compared with baseline, the plasma malondialdehyde and isoprostane levels decreased, whereas superoxide dismutase level and total antioxidant capacity increased in all ASX intervention groups over the 3-week period. In particular, isoprostane levels showed a significant dose-dependent decrease after ASX intake. The results suggest that ASX supplementation might prevent oxidative damage in smokers by suppressing lipid peroxidation and stimulating the activity of the antioxidant system in smokers.

  10. Controlled release of astaxanthin from nanoporous silicified-phospholipids assembled boron nitride complex for cosmetic applications

    Science.gov (United States)

    Lee, Hye Sun; Sung, Dae Kyung; Kim, Sung Hyun; Choi, Won Il; Hwang, Ee Tag; Choi, Doo Jin; Chang, Jeong Ho

    2017-12-01

    Nanoporous silicified-phospholipids assembled boron nitride (nSPLs@BN) powder was prepared and demonstrated for use in controlled release of anti-oxidant astaxanthin (AX) as a cosmetic application. The nanoporous silicified phospholipids (nSPLs) were obtained by the silicification with tetraethyl orthosilicate (TEOS) of the hydrophilic region of phospholipid bilayers. This process involved the co-assembly of chemically active phospholipid bilayers within the porous silica matrix. In addition, nSPLs@BN was characterized using several analytical techniques and tested to assess their efficiency as drug delivery systems. We calculated the maximum release amounts as a function of time and various pH. The release rate of AX from the nSPLs@BN for the initial 24 h was 10.7 μmol/(h mg) at pH 7.4. Furthermore, we determined the antioxidant activity (KD) for the released AX with DPPH (1,1-diphenyl-2-picryl-hydrazyl) radical and the result was 34.6%.

  11. Astaxanthin conjugated polypyrrole nanoparticles as a multimodal agent for photo-based therapy and imaging.

    Science.gov (United States)

    Bharathiraja, Subramaniyan; Manivasagan, Panchanathan; Oh, Yun-Ok; Moorthy, Madhappan Santha; Seo, Hansu; Bui, Nhat Quang; Oh, Junghwan

    2017-01-30

    Polymeric nanoparticles are emerging as promising candidates for photo-based therapy and imaging due to their versatile chemical properties and easy fabrication and functionalization. In the present study we synthesized polypyrrole nanoparticles by stabilization with astaxanthin conjugated bovine serum albumin polymer (PPy@BSA-Astx). The synthesized nanoparticles were biocompatible with MBA-MD-231 and HEK-293 cells. Interestingly, the fabricated nanoparticles produced reactive oxygen species under 808-nm laser exposure and exerted a hyperthermic effect when the power density of the laser was increased. The photodynamic efficiency of PPy@BSA-Astx was measured by DPBF assay, and it was found to generate sufficient amount of reactive radicals to kill the cells at a power density of 0.3W/cm(2). In photothermal aspect, the temperature level was reached to 57°C within 5min at 1W/cm(2) power density, at the concentration of 50μg/mL. The in vitro cell toxicity studies showed concentration dependent photothermal and photodynamic toxicity. Fluorescence microscopic investigation explored the cell death and intra-cellular organ destruction by photodynamic treatment. In addition, we observed a strong photoacoustic signal from a tissue mimicking phantom study of nanoparticle treated MBA-MD-231 cells. In conclusion, the fabricated PPy@BSA-Astx nanoparticles can be used as photoacoustic imaging based prognostic agents for photothermal or photodynamic treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Molecular Properties of Astaxanthin in Water/Ethanol Solutions from Computer Simulations.

    Science.gov (United States)

    Karki, Khadga Jung; Samanta, Susruta; Roccatano, Danilo

    2016-09-08

    Astaxanthin (AXT) is a reference model of xanthophyll carotenoids, which is used in medicine and food industry, and has potential applications in nanotechnology. Because of its importance, there is a great interest in understanding its molecular properties and aggregation mechanism in water and mixed solvents. In this paper, we report a novel model of AXT for molecular dynamics simulation. The model is used to estimate different properties of the molecule in pure solutions and in water/ethanol mixtures. The calculated diffusion coefficients of AXT in pure water and ethanol are (3.22 ± 0.01) × 10(-6) cm(2) s(-1) and (2.7 ± 0.4) × 10(-6) cm(2) s(-1), respectively. Our simulations also show that the content of water plays a clear effect on the morphology of the AXT aggregation in water/ethanol mixture. In up to 75% (v/v) water concentration, a loosely connected network of dimers and trimers and two-dimensional array structures are observed. At higher water concentrations, AXT molecules form more compact three-dimensional structures that are preferentially solvated by the ethanol molecules. The ethanol preferential binding and the formation of a well connected hydrogen bonding network on these AXT clusters, suggest that such preferential solvation can play an important role in controlling the aggregate structure.

  13. Complexes of Small Chiral Molecules: Propylene Oxide and 3-BUTYN-2OL

    Science.gov (United States)

    Evangelisti, Luca; West, Channing; Coles, Ellie; Pate, Brooks

    2017-06-01

    Complexes of propylene oxide with 3-butyn-2-ol were observed in the molecular rotational spectra, and isotopologue analysis allowed for structural determination of the complexes. Using a gas mixture of 0.1% propylene oxide and 0.1% 3-butyn-2-ol in neon, the broadband rotational spectrum was measured in the 2-8 GHz frequency range using a chirped-pulse Fourier transform microwave spectrometer. Four isomers of each diastereomer pair, formed by a hydrogen bond between the two monomers, are identified in quantum chemistry study of the complex using B3LYP-D3BJ with the def2TZVP basis set. The initial measurement used racemic samples of both molecules in order to obtain all possible isomers of the complex in the pulsed jet expansion. A total of six distinct spectra were assigned in the racemic measurement - three for both the homochiral and heterochiral complex. Substitution structures for the most intense homochiral and heterochiral complexes were obtained. These complexes use the two lowest energy conformations of butynol despite conformational cooling of the monomer, resulting in a single identified isomer. This result shows that a wide range monomer conformational geometries need to be examined when performing searches for the lowest energy geometry. Analysis of the diastereomer spectra was used to develop a method for determining the enantiomeric excess of 3-butyn-2-ol and propylene oxide for use as a chiral tag, which could be used in subsequent measurements to determine enantiomeric excess. The sensitivity limits for enantiomeric excess determination and the linearity of the rotational spectroscopy signals as a function of sample enantiomeric excess will be presented.

  14. Chiral dynamics and peripheral transverse densities

    Energy Technology Data Exchange (ETDEWEB)

    Granados, Carlos G. [Uppsala University (Sweden); Weiss, Christian [JLAB, Newport News, VA (United States)

    2014-01-01

    In the partonic (or light-front) description of relativistic systems the electromagnetic form factors are expressed in terms of frame-independent charge and magnetization densities in transverse space. This formulation allows one to identify the chiral components of nucleon structure as the peripheral densities at transverse distances b = O(M{sub {pi}}{sup -1}) and compute them in a parametrically controlled manner. A dispersion relation connects the large-distance behavior of the transverse charge and magnetization densities to the spectral functions of the Dirac and Pauli form factors near the two--pion threshold at timelike t = 4 M{ sub {pi}}{sup 2}, which can be computed in relativistic chiral effective field theory. Using the leading-order approximation we (a) derive the asymptotic behavior (Yukawa tail) of the isovector transverse densities in the "chiral" region b = O(M{sub {pi}}{sup -1}) and the "molecular" region b = O(M{sub N}{sup 2}/M{sub {pi}}{sup 3}); (b) perform the heavy-baryon expansion of the transverse densities; (c) explain the relative magnitude of the peripheral charge and magnetization densities in a simple mechanical picture; (d) include Delta isobar intermediate states and study the peripheral transverse densities in the large-N{ sub c} limit of QCD; (e) quantify the region of transverse distances where the chiral components of the densities are numerically dominant; (f) calculate the chiral divergences of the b{sup 2}-weighted moments of the isovector transverse densities (charge and anomalous magnetic radii) in the limit M{sub {pi}} -> 0 and determine their spatial support. Our approach provides a concise formulation of the spatial structure of the nucleon's chiral component and offers new insights into basic properties of the chiral expansion. It relates the information extracted from low-t elastic form factors to the generalized parton distributions probed in peripheral high-energy scattering processes.

  15. Chiral separation of helical chromenes with chloromethyl phenylcarbamate polysaccharide-based stationary phases.

    Science.gov (United States)

    Ianni, Federica; Scorzoni, Stefania; Gentili, Pier Luigi; Di Michele, Alessandro; Frigoli, Michel; Camaioni, Emidio; Ortica, Fausto; Sardella, Roccaldo

    2017-12-12

    Two chloromethyl phenylcarbamate-based chiral stationary phases, one containing an amylose-type chiral selector (Lux Amylose 2, from Phenomenex) and the other a cellulose-type one (Lux Cellulose-4, from Phenomenex), were successfully used for the chiral resolution of three helical chromenes featuring a helicene-like structure. The compound bearing a phenyl substituent on the helicene-like structure was enantioresolved at 25°C with Lux Cellulose-4 and a n-hexane/1-propanol 99:1 v/v eluent. With a n-hexane/2-propanol 99.8:0.2 v/v mobile phase, the same column (operated at 35°C) provided the separation of the four isomers of the compound having a hexyl residue on the helicene-like motif and an additional asymmetric carbon. Lux Amylose-2 was necessary for the enantioseparation of the compound having the sole hexyl residue on the helical scaffold. For the last compound a n-hexane/2-propanol 99.8:0.2 v/v eluent was used, and the column temperature was fixed at 5°C. The enantiomer elution order was appraised by using electronic circular dichroism and theoretical calculations. Notably, different thermodynamics of retention and enantioseparation were observed for molecules with pronounced structural similarity, that is, the enantiomer pairs of the compound containing the additional asymmetric carbon atom. Indeed, both entropically and enthalpically controlled adsorption and separation processes were observed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. General form of intramolecular nuclear spin isomers mixing in C3v -symmetry

    Science.gov (United States)

    Il'ichov, L. V.

    2017-10-01

    Molecules with identical nuclei exist in nature in the form of nuclear spin isomers. In general, spin isomers are not the eigenstates of total molecular Hamiltonian. It also contains parts able to transform spin isomers one into another. Recently, nuclear spin isomers relaxation induced by such a quantum mixing was successfully demonstrated in experiment. That motivates the search for general intramolecular interactions able to mix spin isomers. In the work, the general forms of the possible mixing interactions are found for C3v-type of molecules using generalized Jordan-Schwinger approach to the theory of quantum angular momentum.

  17. Enantioselective catalytic syntheses of alpha-branched chiral amines

    DEFF Research Database (Denmark)

    Brase, S.; Baumann, T.; Dahmen, S.

    2007-01-01

    Chiral amines play a pivotal role in fine chemical and natural product syntheses and the design of novel materials.......Chiral amines play a pivotal role in fine chemical and natural product syntheses and the design of novel materials....

  18. Chiral liquid phase of simple quantum magnets

    Science.gov (United States)

    Wang, Zhentao; Feiguin, Adrian E.; Zhu, Wei; Starykh, Oleg A.; Chubukov, Andrey V.; Batista, Cristian D.

    2017-11-01

    We study a T =0 quantum phase transition between a quantum paramagnetic state and a magnetically ordered state for a spin S =1 XXZ Heisenberg antiferromagnet on a two-dimensional triangular lattice. The transition is induced by an easy-plane single-ion anisotropy D . At the mean-field level, the system undergoes a direct transition at a critical D =Dc between a paramagnetic state at D >Dc and an ordered state with broken U(1 ) symmetry at D field the phase diagram is very different and includes an intermediate, partially ordered chiral liquid phase. Specifically, we find that inside the paramagnetic phase the Ising (Jz) component of the Heisenberg exchange binds magnons into a two-particle bound state with zero total momentum and spin. This bound state condenses at D >Dc , before single-particle excitations become unstable, and gives rise to a chiral liquid phase, which spontaneously breaks spatial inversion symmetry, but leaves the spin-rotational U(1 ) and time-reversal symmetries intact. This chiral liquid phase is characterized by a finite vector chirality without long-range dipolar magnetic order. In our analytical treatment, the chiral phase appears for arbitrarily small Jz because the magnon-magnon attraction becomes singular near the single-magnon condensation transition. This phase exists in a finite range of D and transforms into the magnetically ordered state at some D calculations.

  19. Characteristics of Butanol Isomers Oxidation in a Micro Flow Reactor

    KAUST Repository

    Bin Hamzah, Muhamad Firdaus

    2017-05-01

    Ignition and combustion characteristics of n-butanol/air, 2-butanol.air and isobutanol/air mixtures at stoichiometric (ϕ = 1) and lean (ϕ = 0.5) conditions were investigated in a micro flow reactor with a controlled temperature profile from 323 K to 1313 K, under atmospheric pressure. Sole distinctive weak flame was observed for each mixture, with inlet fuel/air mixture velocity set low at 2 cm/s. One-dimensional computation with comprehensive chemistry and transport was conducted. At low mixture velocities, one-stage oxidation was confirmed from heat release rate profiles, which was broadly in agreement with the experimental results. The weak flame positions were congruent with literature describing reactivity of the butanol isomers. These weak flame responses were also found to mirror the trend in Anti-Knock Indexes of the butanol isomers. Flux and sensitivity analyses were performed to investigate the fuel oxidation pathways at low and high temperatures. Further computational investigations on oxidation of butanol isomers at higher pressure of 5 atm indicated two-stage oxidation through the heat release rate profiles. Low temperature chemistry is accentuated in the region near the first weak cool flame for oxidation under higher pressure, and its impact on key species – such as hydroxyl radical, hydrogen peroxide and carbon monoxide – were considered. Both experimental and computational findings demonstrate the advantage of employing the micro flow reactor in investigating oxidation processes in the temperature region of interest along the reactor channel. By varying physical conditions such as pressure, the micro flow reactor system is proven to be highly beneficial in elucidating oxidation behavior of butanol isomers in conditions in engines such as those that mirror HCCI operations.

  20. Island of high-spin isomers near N = 82

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, J.; Back, B.B.; Bernthal, F.M.; Bjornholm, S.; Borggreen, J.; Christensen, O.; Folkmann, F.; Herskind, B.; Khoo, T.L.; Neiman, M.; Puehlhofer, F.; Sletten, G.

    1977-10-17

    Experiments aimed at testing for the existence of yrast traps are reported. A search for delayed ..gamma.. radiation of lifetimes longer than approx. 10 ns and of high multiplicity has been performed by producing more than 100 compound nuclei between Ba and Pb in bombardments with /sup 40/Ar, /sup 50/Ti, and /sup 65/Cu projectiles. An island of high-spin isomers is found to exist in the region 64 < or approx. = Z > or approx. = 71 and N < or approx. = 82.

  1. Influence of microemulsion chirality on chromatographic figures of merit in EKC: results with novel three-chiral-component microemulsions and comparison with one- and two-chiral-component microemulsions.

    Science.gov (United States)

    Kahle, Kimberly A; Foley, Joe P

    2007-08-01

    Novel microemulsion formulations containing all chiral components are described for the enantioseparation of six pairs of pharmaceutical enantiomers (atenolol, ephedrine, metoprolol, N-methyl ephedrine, pseudoephedrine, and synephrine). The chiral surfactant dodecoxycarbonylvaline (DDCV, R- and S-), the chiral cosurfactant S-2-hexanol, and the chiral oil diethyl tartrate (R- and S-) were combined to create four different chiral microemulsions, three of which were stable. Results obtained for enantioselectivity, efficiency, and resolution were compared for the triple-chirality systems and the single-chirality system that contained chiral surfactant only. Improvements in enantioselectivity and resolution were achieved by simultaneously incorporating three chiral components into the aggregate. The one-chiral-component microemulsion provided better efficiencies. Enantioselective synergies were identified for the three-chiral-component nanodroplets using a thermodynamic model. Additionally, two types of dual-chirality systems, chiral surfactant/chiral cosurfactant and chiral surfactant/chiral oil, were examined in terms of chromatographic figures of merit, with the former providing much better resolution. The two varieties of two-chiral-component microemulsions gave similar values for enantioselectivity and efficiency. Lastly, the microemulsion formulations were divided into categories based on the number of chiral microemulsion reagents and the average results for each pair of enantiomers were analyzed for trends. In general, enantioselectivity and resolution were enhanced while efficiency was decreased as more chiral components were used to create the pseudostationary phase (PSP).

  2. Electron attachment and detachment: Electron affinities of isomers of trifluoromethylbenzonitrile

    Science.gov (United States)

    Miller, Thomas M.; Viggiano, A. A.; Friedman, Jeffrey F.; Van Doren, Jane M.

    2004-11-01

    Rate constants for electron attachment to the three isomers of trifluoromethylbenzonitrile [(CF3)(CN)C6H4, or TFMBN] were measured over the temperature range of 303-463 K in a 133-Pa He buffer gas, using a flowing-afterglow Langmuir-probe apparatus. At 303 K, the measured attachment rate constants are 9.0×10-8 (o-TFMBN), 5.5×10-8 (m-TFMBN), and 8.9×10-8 cm3 s-1 (p-TFMBN), estimated accurate to ±25%. The attachment process formed only the parent anion in all three cases. Thermal electron detachment was observed for all three anion isomers, and rate constants for this reverse process were also measured. From the attachment and detachment results, the electron affinities of the three isomers of TFMBN were determined to be 0.70(o-TFMBN), 0.67(m-TFMBN), and 0.83 eV (p-TFMBN), all ±0.05 eV. G3(MP2) [Gaussian-3 calculations with reduced Møller-Plesset orders (MP2)] calculations were carried out for the neutrals and anions. Electron affinities derived from these calculations are in good agreement with the experimental values.

  3. Three bilindione isomers: synthesis, characterization and reactivity of biliverdin analogs.

    Science.gov (United States)

    Wang, Jun-Fei; Ma, Fang; Sun, Hao-Ling; Zhang, Jing; Zhang, Jun-Long

    2017-07-01

    Linear tetrapyrrole is the core structure of light-sensitive native cofactors such as phycocyanobilin, phytochromobilin and bile pigments, which attracts increasing attention in biomimetic chemistry, photochemistry and coordination chemistry. To decipher the relationship between structures and functions, in this work, we firstly reported the synthesis, isolation and characterization of three bilindione isomers (ZZZ, syn, syn, syn 1, EZE, syn, syn, anti 2 and EZE, anti, syn, anti 3) bearing meso-pentafluorophenyl groups. The structures were confirmed by X-ray diffraction and 2-D NMR spectroscopes. More importantly, the interconversion between three isomers under heating and light irradiation was investigated, and isomer 3 was found to be transformed to 1 and 2 more easily, which is in line with the results of DFT calculation. This work provides important insights for understanding the relationship between structures and functions and would be important to further construct metal complexes based on linear tetrapyrrole ligands, which are complementary to well-studied the cyclic analogs such as porphyrin and corroles.

  4. Isomer probes of nuclear structure following deep inelastic collisions

    CERN Document Server

    Al-Garni, S A; Walker, P

    2002-01-01

    Deep-inelastic collisions of sup 1 sup 3 sup 6 Xe ions with tantalum, tungsten and rhenium targets have been used to study beta-decays and high-spin isomers in neutron-rich A approx 180 nuclei at the GSI on-line mass separator. In particular, gamma rays -associated with the decay of the previously identified K suppi = 37/2 sup - , T sub 1 sub / sub 2 = 51 min isomer in sup 1 sup 7 sup 7 Hf have been observed, but with an unexpectedly high yield considering the release efficiency for short-lived hafnium isotopes from a thermal ion source. These results may be interpreted as possible evidence for a hitherto unrecognised, high-spin beta-decaying isomer in sup 1 sup 7 sup 7 Lu. A two-component half-life analysis of the sup 1 sup 7 sup 7 Hf gamma-ray intensities gives an upper-lying component of 6 + 3 - 2 min, when the lower-lying component half-life is fixed at 51 min. Nilsson multi-quasiparticle calculations with BCS pairing predict a favoured K suppi = 39/2 sup - state in sup 1 sup 7 sup 7 Lu, which is a candid...

  5. Borromean halo, Tango halo, and halo isomers in atomic nuclei

    Science.gov (United States)

    Izosimov, Igor

    2016-01-01

    Structure of the ground and excited states in halo-like nuclei is discussed. Both the Borromean and tango halo types can be observed for n-p configurations of atomic nuclei.Structure of the halo may be different for the different levels and resonances in atomic nuclei. Isobar analog, double isobar analog, configuration, and double configuration states can simultaneously have n-n, n-p, and p-p halo components in their wave functions. When the halo structure of the excited state differs from that of the ground state, or the ground state has non-halo structure, the γ-transition from the excited state to the ground state can be essentially hindered, i.e. the formation of a specific type of isomers (halo isomers) becomes possible. B(Mγ) and B(Eγ) values for γ-transitions in 6,7,8Li, 8,9,10Be, 8,10,11B, 10,11,12,13,14C, 13,14,15,16,17N, 15,16,17,19O, and 17F are analyzed. Special attention is given to nuclei which ground state does not exhibit halo structure but the excited state (halo isomer) may have one.

  6. Distinct carbon isotope fractionation during anaerobic degradation of dichlorobenzene isomers.

    Science.gov (United States)

    Liang, Xiaoming; Mundle, Scott O C; Nelson, Jennifer L; Passeport, Elodie; Chan, Calvin C H; Lacrampe-Couloume, Georges; Zinder, Stephen H; Sherwood Lollar, Barbara

    2014-05-06

    Chlorinated benzenes are ubiquitous organic contaminants found in groundwater and soils. Compound specific isotope analysis (CSIA) has been increasingly used to assess natural attenuation of chlorinated contaminants, in which anaerobic reductive dechlorination plays an essential role. In this work, carbon isotope fractionation of the three dichlorobenzene (DCB) isomers was investigated during anaerobic reductive dehalogenation in methanogenic laboratory microcosms. Large isotope fractionation of 1,3-DCB and 1,4-DCB was observed while only a small isotope effect occurred for 1,2-DCB. Bulk enrichment factors (εbulk) were determined from a Rayleigh model: -0.8 ± 0.1 ‰ for 1,2-DCB, -5.4 ± 0.4 ‰ for 1,3-DCB, and -6.3 ± 0.2 ‰ for 1,4-DCB. εbulk values were converted to apparent kinetic isotope effects for carbon (AKIE) in order to characterize the carbon isotope effect at the reactive positions for the DCB isomers. AKIE values are 1.005 ± 0.001, 1.034 ± 0.003, and 1.039 ± 0.001 for 1,2-DCB, 1,3-DCB, and 1,4-DCB, respectively. The large difference in AKIE values between 1,2-DCB and 1,3-DCB (or 1,4-DCB) suggests distinct reaction pathways may be involved for different DCB isomers during microbial reductive dechlorination by the methanogenic cultures.

  7. Infrared spectroscopic study on hydration and chiral interaction of temperature-responsive polymer with L-proline moieties.

    Science.gov (United States)

    Hirano, Tatsuya; Sugihara, Shinji; Maeda, Yasushi

    2013-12-19

    We studied the hydration of a temperature-responsive polymer containing L-proline moieties (poly(acryloyl-L-proline methyl ester), PAProM) by using infrared spectroscopy. Red shifts of ν(C-H) bands and blue shifts of amide and ester carbonyl bands of PAProM during temperature-induced phase separation indicate that the alkyl, amide, and ester groups are partially dehydrated. The population of the amide carbonyls forming hydrogen bonds (H-bonds) with two water molecules decreased from 63 to 33%, while that of the ester carbonyls forming one H bonding decreased from 100 to 84%. We labeled the methyl groups of PAProM by introducing deuterium (poly(acryloyl-L-proline methyl-d3 ester, PAProMd3) to clarify hydration change of the labeled groups. Red shifts of three ν(C-D) bands appearing at 2000-2200 cm(-1) clearly showed that the methyl groups at the end of side chains also dehydrated as well as the alkyl groups on the main chain. As for the effects of additives, methanol raised the phase separation temperature (Tp) of PAProM. The IR spectra show that the average number of H bonds to the amide and ester carbonyls decreases with increasing methanol concentration and that the water molecules surrounding the alkyl groups of PAProM are replaced by methanol molecules. The increase in Tp suggests that the favorable effect of the latter is superior to the unfavorable effect of the former. On the other hand, malic acid (MA) reduced Tp of PAProM. Moreover, a chiral interaction occurs; that is, Tp was lower in the presence of d-isomer than L-isomer. The analysis of the amide band revealed that the d-isomer associates more effectively with the amide carbonyls of PAProM than the L-isomer does.

  8. New chiral ligand exchange capillary electrophoresis system with chiral amino amide ionic liquids as ligands.

    Science.gov (United States)

    Jiang, Junfang; Mu, Xiaoyu; Qiao, Juan; Su, Yuan; Qi, Li

    2017-12-01

    Using chiral amino amide ionic liquids as the ligands, a new chiral ligand exchange capillary electrophoresis method with Cu(II) as the central ion was constructed for enantioseparation of labeled D,L-amino acids. The effects of key parameters, including pH value of the running buffer, the ratio of Cu(II) to chiral amino amide ionic liquids, the concentration of complexes based on Cu(II)-chiral amino amide ionic liquids were investigated. It has been observed that eight pairs of labeled D,L-amino acids could be baseline-separated with a running buffer of 15.0mM ammonium acetate, 10.0mM Cu(II) and 20.0mML-phenylalaninamide based ionic liquid at pH 5.0. The quantitation of D,L-amino acids was conducted and good linearity (r2 ≥ 0.964) was obtained. Furthermore, an assay for determining the enantiomeric purity of D,L-amino acids was developed and the possible enantiorecognition mechanism was discussed briefly. The results indicated that the chiral amino amide ionic liquids could play the role of ligands in chiral ligand exchange capillary electrophoresis system and exhibit great potential in chiral analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. A Review on Chiral Chromatography and its Application to the ...

    African Journals Online (AJOL)

    MoZarD

    overview of chiral separations to researchers who are versed in the area of ... This review highlights significant issues of the chiral separations and provides salient examples from specific classes of chiral selectors where appropriate. Terms and Definitions ..... molecule. This three-point interaction rule is generally valid for ...

  10. Penambahan Astaxanthin pada Pengencer Kuning Telur Berbagai Jenis Unggas Dapat Memproteksi Semen Babi Selama Penyimpanan (THE ADDITION OF ASTAXANTHIN ON SPERM DILUENTS PHOSPHATE EGGYOLK OF VARIOUS POULTRY CAN PROTECT QUALITY OF PIG SPERM DURING STORAGE

    Directory of Open Access Journals (Sweden)

    Wayan Bebas

    2017-01-01

    Full Text Available A study was conducted to formulate semen diluent of pigswith a better quality, cheap and easy toprepare using egg yolk of various poultries such as chickens, ducks and quails in combinationwithastaxanthin, a potent antioxidant. The research design used was a completely randomized factorialdesign with three different types of sperm diluents and four levels of astaxanthin concentration. Spermdiluents used were phosphate duck egg yolk, phosphate quail egg yolk and yolks phosphate supplementedrespectivelywith 0,002%, 0,004% and 0,008%astaxanthine. The treated sperm were strored at 5oC for 48hours. The sperm qualities were examined for progressive motility, spermatozoa abnormalities, viabilityand plasma membrane integrity. The result showed that sperm diluents of using duck egg yolk phosphatein combination with 0.002% astaxanthinresulted in the highest progressive motility, viability and plasmamembrane intact while abnormalities spermatozoa is lowest. It can be concluded that phosphate duck eggyolk sperm diluents with the addition of 0,002% astaxanthinappeared to be able to maintain the qualityof pig sperm stored at 5oC for 48 hours.

  11. Magnetic test of chiral dynamics in QCD

    Energy Technology Data Exchange (ETDEWEB)

    Simonov, Yu.A. [Institute of Theoretical and Experimental Physics,117118, Moscow, B. Cheremushkinskaya 25 (Russian Federation)

    2014-01-22

    Strong magnetic fields in the range eB≫m{sub π}{sup 2} effectively probe internal quark structure of chiral mesons and test basic parameters of the chiral theory, such as 〈q-barq〉,f{sub π}. We argue on general grounds that 〈q-barq〉 should grow linearly with eB when charged quark degrees of freedom come into play. To make explicit estimates we extend the previously formulated chiral theory, including quark degrees of freedom, to the case of strong magnetic fields and show that the quark condensate |〈q-barq〉|{sub u,d} grows quadratically with eB for eB<0.2 GeV{sup 2} and linearly for higher field values. These results agree quantitatively with recent lattice data and differ from χPT predictions.

  12. Chiral light by symmetric optical antennas

    CERN Document Server

    Mekonnen, Addis; Zubritskaya, Irina; Jönsson, Gustav Edman; Dmitriev, Alexandre

    2014-01-01

    Chirality is at the origin of life and is ubiquitous in nature. An object is deemed chiral if it is non-superimposable with its own mirror image. This relates to how circularly polarized light interacts with such object, a circular dichroism, the differential absorption of right and left circularly polarized light. According to the common understanding in biology, chemistry and physics, the circular dichroism results from an internal chiral structure or external symmetry breaking by illumination. We show that circular dichroism is possible with simple symmetric optical nanoantennas at symmetric illumination. We experimentally and theoretically demonstrate that two electromagnetic dipole-like modes with a phase lag, in principle, suffice to produce circular dichroism in achiral structure. Examples of the latter are all visible spectrum optical nanoantennas, symmetric nanoellipses and nanodimers. The simplicity and generality of this finding reveal a whole new significance of the electromagnetic design at a nan...

  13. On chiral-odd Generalized Parton Distributions

    Energy Technology Data Exchange (ETDEWEB)

    Wallon, Samuel [Laboratoire de Physique Theorique d' Orsay - LPT, Bat. 210, Univ. Paris-Sud 11, 91405 Orsay Cedex (France); UPMC Univ. Paris 6, Paris (France); Pire, Bernard [Centre de Physique Theorique - CPHT, UMR 7644, Ecole Polytechnique, Bat. 6, RDC, F91128 Palaiseau Cedex (France); Szymanowski, Lech [Soltan Institute for Nuclear Studies, Hoza 69, 00691, Warsaw (Poland)

    2010-07-01

    The chiral-odd transversity generalized parton distributions of the nucleon can be accessed experimentally through the exclusive photoproduction process {gamma} + N {yields} {pi} + {rho} + N', in the kinematics where the meson pair has a large invariant mass and the final nucleon has a small transverse momentum, provided the vector meson is produced in a transversally polarized state. Estimated counting rates show that the experiment is feasible with real or quasi real photon beams expected at JLab at 12 GeV and in the COMPASS experiment. (Phys Letters B688,154,2010) In addition, a consistent classification of the chiral-odd pion GPDs beyond the leading twist 2 is presented. Based on QCD equations of motion and on the invariance under rotation on the light-cone of any scattering amplitude involving such GPDs, we reduce the basis of these chiral-odd GPDs to a minimal set. (author)

  14. Chiral Perturbation Theory With Lattice Regularization

    CERN Document Server

    Ouimet, P P A

    2005-01-01

    In this work, alternative methods to regularize chiral perturbation theory are discussed. First, Long Distance Regularization will be considered in the presence of the decuplet of the lightest spin 32 baryons for several different observables. This serves motivation and introduction to the use of the lattice regulator for chiral perturbation theory. The mesonic, baryonic and anomalous sectors of chiral perturbation theory will be formulated on a lattice of space time points. The consistency of the lattice as a regulator will be discussed in the context of the meson and baryon masses. Order a effects will also be discussed for the baryon masses, sigma terms and magnetic moments. The work will close with an attempt to derive an effective Wess-Zumino-Witten Lagrangian for Wilson fermions at non-zero a. Following this discussion, there will be a proposal for a phenomenologically useful WZW Lagrangian at non-zero a.

  15. Chiral geometry in symmetry-restored states: Chiral doublet bands in 128Cs

    Science.gov (United States)

    Chen, F. Q.; Chen, Q. B.; Luo, Y. A.; Meng, J.; Zhang, S. Q.

    2017-11-01

    The pairing-plus-quadrupole Hamiltonian is diagonalized in a symmetry-restored basis, i.e., the triaxial quasiparticle states with angular momentum and particle number projections, and applied for chiral doublet bands in 128Cs. The observed energy spectra and electromagnetic transition probabilities are reproduced well without introducing any parameters. The orientation of the angular momentum in the intrinsic frame is investigated by the distributions of its components on the three principle axes (K plot) and those of its tilted angles (azimuthal plot). The evolution of the chirality with spin is illustrated, and the chiral geometry is demonstrated in the angular momentum projected model for the first time.

  16. Sodiation as a tool for enhancing the diagnostic value of MALDI-TOF/TOF-MS spectra of complex astaxanthin ester mixtures from Haematococcus pluvialis

    NARCIS (Netherlands)

    Weesepoel, Y.J.A.; Vincken, J.P.; Pop, R.M.; Liu, K.; Gruppen, H.

    2013-01-01

    The microalga Haematococcus pluvialis produces the pigment astaxanthin mainly in esterified form with a multitude of fatty acids, which results in a complex mixture of carotenol mono- and diesters. For rapid fingerprinting of these esters, matrix-assisted laser desorption ionization time of flight

  17. Reconstruction of the astaxanthin biosynthesis pathway in rice endosperm reveals a metabolic bottleneck at the level of endogenous β-carotene hydroxylase activity.

    Science.gov (United States)

    Bai, Chao; Berman, Judit; Farre, Gemma; Capell, Teresa; Sandmann, Gerhard; Christou, Paul; Zhu, Changfu

    2017-02-01

    Astaxanthin is a high-value ketocarotenoid rarely found in plants. It is derived from β-carotene by the 3-hydroxylation and 4-ketolation of both ionone end groups, in reactions catalyzed by β-carotene hydroxylase and β-carotene ketolase, respectively. We investigated the feasibility of introducing an extended carotenoid biosynthesis pathway into rice endosperm to achieve the production of astaxanthin. This allowed us to identify potential metabolic bottlenecks that have thus far prevented the accumulation of this valuable compound in storage tissues such as cereal grains. Rice endosperm does not usually accumulate carotenoids because phytoene synthase, the enzyme responsible for the first committed step in the pathway, is not present in this tissue. We therefore expressed maize phytoene synthase 1 (ZmPSY1), Pantoea ananatis phytoene desaturase (PaCRTI) and a synthetic Chlamydomonas reinhardtii β-carotene ketolase (sCrBKT) in transgenic rice plants under the control of endosperm-specific promoters. The resulting grains predominantly accumulated the diketocarotenoids canthaxanthin, adonirubin and astaxanthin as well as low levels of monoketocarotenoids. The predominance of canthaxanthin and adonirubin indicated the presence of a hydroxylation bottleneck in the ketocarotenoid pathway. This final rate-limiting step must therefore be overcome to maximize the accumulation of astaxanthin, the end product of the pathway.

  18. Improved Hepatoprotective Effect of Liposome-Encapsulated Astaxanthin in Lipopolysaccharide-Induced Acute Hepatotoxicity

    Directory of Open Access Journals (Sweden)

    Chun-Hung Chiu

    2016-07-01

    Full Text Available Lipopolysaccharide (LPS-induced acute hepatotoxicity is significantly associated with oxidative stress. Astaxanthin (AST, a xanthophyll carotenoid, is well known for its potent antioxidant capacity. However, its drawbacks of poor aqueous solubility and low bioavailability have limited its utility. Liposome encapsulation is considered as an effective alternative use for the improvement of bioavailability of the hydrophobic compound. We hypothesized that AST encapsulated within liposomes (LA apparently shows improved stability and transportability compared to that of free AST. To investigate whether LA administration can efficiently prevent the LPS-induced acute hepatotoxicity, male Sprague-Dawley rats (n = six per group were orally administered liposome-encapsulated AST at 2, 5 or 10 mg/kg-day (LA-2, LA-5, and LA-10 for seven days and then were LPS-challenged (i.p., 5 mg/kg. The LA-10 administered group, but not the other groups, exhibited a significant amelioration of serum glutamic pyruvic transaminase (GPT, glutamic oxaloacetic transaminase (GOT, blood urea nitrogen (BUN, creatinine (CRE, hepatic malondialdehyde (MDA and glutathione peroxidase (GSH-Px, IL-6, and hepatic nuclear NF-κB and inducible nitric oxide synthase (iNOS, suggesting that LA at a 10 mg/kg-day dosage renders hepatoprotective effects. Moreover, the protective effects were even superior to that of positive control N-acetylcysteine (NAC, 200 mg/kg-day. Histopathologically, NAC, free AST, LA-2 and LA-5 partially, but LA-10 completely, alleviated the acute inflammatory status. These results indicate that hydrophobic AST after being properly encapsulated by liposomes improves bioavailability and can also function as potential drug delivery system in treating hepatotoxicity.

  19. Astaxanthin Protects Primary Hippocampal Neurons against Noxious Effects of Aβ-Oligomers

    Directory of Open Access Journals (Sweden)

    Pedro Lobos

    2016-01-01

    Full Text Available Increased reactive oxygen species (ROS generation and the ensuing oxidative stress contribute to Alzheimer’s disease pathology. We reported previously that amyloid-β peptide oligomers (AβOs produce aberrant Ca2+ signals at sublethal concentrations and decrease the expression of type-2 ryanodine receptors (RyR2, which are crucial for hippocampal synaptic plasticity and memory. Here, we investigated whether the antioxidant agent astaxanthin (ATX protects neurons from AβOs-induced excessive mitochondrial ROS generation, NFATc4 activation, and RyR2 mRNA downregulation. To determine mitochondrial H2O2 production or NFATc4 nuclear translocation, neurons were transfected with plasmids coding for HyperMito or NFATc4-eGFP, respectively. Primary hippocampal cultures were incubated with 0.1 μM ATX for 1.5 h prior to AβOs addition (500 nM. We found that incubation with ATX (≤10 μM for ≤24 h was nontoxic to neurons, evaluated by the live/dead assay. Preincubation with 0.1 μM ATX also prevented the neuronal mitochondrial H2O2 generation induced within minutes of AβOs addition. Longer exposures to AβOs (6 h promoted NFATc4-eGFP nuclear translocation and decreased RyR2 mRNA levels, evaluated by detection of the eGFP-tagged fluorescent plasmid and qPCR, respectively. Preincubation with 0.1 μM ATX prevented both effects. These results indicate that ATX protects neurons from the noxious effects of AβOs on mitochondrial ROS production, NFATc4 activation, and RyR2 gene expression downregulation.

  20. Astaxanthin Improves Human Sperm Capacitation by Inducing Lyn Displacement and Activation

    Directory of Open Access Journals (Sweden)

    Alessandra Andrisani

    2015-08-01

    Full Text Available Astaxanthin (Asta, a photo-protective red pigment of the carotenoid family, is known for its multiple beneficial properties. In this study, the effects of Asta on isolated human sperm were evaluated. Capacitation involves a series of transformations to let sperm acquire the correct features for potential oocyte fertilization, including the generation of a controlled amount of reactive oxygen species (ROS, cholesterol depletion of the sperm outer membrane, and protein tyrosine phosphorylation (Tyr-P process in the head region. Volunteers, with normal spermiogram values, were divided in two separate groups on the basis of their ability to generate the correct content of endogenous ROS. Both patient group (PG and control group (CG were analysed for Tyr-phosphorylation (Tyr-P pattern and percentages of acrosome-reacted cells (ARC and non-viable cells (NVC, in the presence or absence of Asta. In addition, the involvement of ROS on membrane reorganization and the presence of Lyn, a Src family kinase associated with lipid rafts, were investigated. Results show that Lyn is present in the membranes of human sperm, mainly confined in midpiece in resting conditions. Following capacitation, Lyn translocated to the head concomitantly with raft relocation, thus allowing the Tyr-P of head proteins. Asta succeeded to trigger Lyn translocation in PG sperm thus bypassing the impaired ROS-related mechanism for rafts and Lyn translocation. In this study, we showed an interdependence between ROS generation and lipid rafts and Lyn relocation leading the cells to undergo the successive acrosome reaction (AR. Asta, by ameliorating PG sperm functioning, may be utilised to decrease male idiopathic infertility.

  1. Astaxanthin Improves Human Sperm Capacitation by Inducing Lyn Displacement and Activation.

    Science.gov (United States)

    Andrisani, Alessandra; Donà, Gabriella; Tibaldi, Elena; Brunati, Anna Maria; Sabbadin, Chiara; Armanini, Decio; Alvisi, Gualtiero; Gizzo, Salvatore; Ambrosini, Guido; Ragazzi, Eugenio; Bordin, Luciana

    2015-08-25

    Astaxanthin (Asta), a photo-protective red pigment of the carotenoid family, is known for its multiple beneficial properties. In this study, the effects of Asta on isolated human sperm were evaluated. Capacitation involves a series of transformations to let sperm acquire the correct features for potential oocyte fertilization, including the generation of a controlled amount of reactive oxygen species (ROS), cholesterol depletion of the sperm outer membrane, and protein tyrosine phosphorylation (Tyr-P) process in the head region. Volunteers, with normal spermiogram values, were divided in two separate groups on the basis of their ability to generate the correct content of endogenous ROS. Both patient group (PG) and control group (CG) were analysed for Tyr-phosphorylation (Tyr-P) pattern and percentages of acrosome-reacted cells (ARC) and non-viable cells (NVC), in the presence or absence of Asta. In addition, the involvement of ROS on membrane reorganization and the presence of Lyn, a Src family kinase associated with lipid rafts, were investigated. Results show that Lyn is present in the membranes of human sperm, mainly confined in midpiece in resting conditions. Following capacitation, Lyn translocated to the head concomitantly with raft relocation, thus allowing the Tyr-P of head proteins. Asta succeeded to trigger Lyn translocation in PG sperm thus bypassing the impaired ROS-related mechanism for rafts and Lyn translocation. In this study, we showed an interdependence between ROS generation and lipid rafts and Lyn relocation leading the cells to undergo the successive acrosome reaction (AR). Asta, by ameliorating PG sperm functioning, may be utilised to decrease male idiopathic infertility.

  2. Astaxanthin protects against oxidative stress and calcium-induced porcine lens protein degradation.

    Science.gov (United States)

    Wu, Tzu-Hua; Liao, Jiahn-Haur; Hou, Wen-Chi; Huang, Fu-Yung; Maher, Timothy J; Hu, Chao-Chien

    2006-03-22

    Astaxanthin (ASTX), a carotenoid with potent antioxidant properties, exists naturally in various plants, algae, and seafoods. In this study, we investigated the in vitro ability of ASTX to protect porcine lens crystallins from oxidative damage by iron-mediated hydroxyl radicals or by calcium ion-activated protease (calpain), in addition to the possible underlying biochemical mechanisms. ASTX (1 mM) was capable of protecting lens crystallins from being oxidized, as measured by changes in tryptophan fluorescence, in the presence of a Fenton reaction solution containing 0.2 mM Fe2+ and 2 mM H2O2. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis demonstrated that beta(high)-crystallin was the most vulnerable protein under these conditions of free radical exposure. The proteolysis of lens crystallins induced by calcium ion-activated calpain was also inhibited by ASTX (0.03-1 mM) as determined by daily measurement of the light-scattering intensity at 405 nm for five consecutive days. ASTX at 1 mM was as potent as a concentration of 0.1 mM calpain inhibitor E64 in protecting the oxidative damage/hydrolysis of porcine crystallins. At a concentration of 1 mM, ASTX provided better protection than the endogenous antioxidant glutathione in terms of suppressing calcium-induced turbidity of lens proteins. Thin-layer chromatography analysis indicated that ASTX interacted with calcium ions to form complexes, which we believe interfere with the hydrolysis of lens crystallins by calcium-activated calpain. This in vitro study shows that ASTX is capable of protecting porcine lens proteins from oxidative insults and degradation by calcium-induced calpain.

  3. Efficacy of Astaxanthin for the Treatment of Atopic Dermatitis in a Murine Model.

    Directory of Open Access Journals (Sweden)

    Yoko Yoshihisa

    Full Text Available Atopic dermatitis (AD is a common chronic inflammatory skin disease associated with various factors, including immunological abnormalities and exposure to allergens. Astaxanthin (AST is a xanthophyll carotenoid that has recently been demonstrated to have anti-inflammatory effects and to regulate the expression of inflammatory cytokines. Thus, we investigated whether AST could improve the dermatitis and pruritus in a murine model of AD using NC/Nga mice. In addition to a behavioral evaluation, the effects of AST on the AD were determined by the clinical skin severity score, serum IgE level, histological analyses of skin, and by reverse transcription-PCR and Western blotting analyses for the expression of inflammation-related factors. AST (100 mg/kg or vehicle (olive oil was orally administered once day and three times a week for 26 days. When compared with vehicle-treated group, the administration of AST significantly reduced the clinical skin severity score. In addition, the spontaneous scratching in AD model mice was reduced by AST administration. Moreover, the serum IgE level was markedly decreased by the oral administration of AST compared to that in vehicle-treated mice. The number of eosinophils, total and degranulated mast cells all significantly decreased in the skin of AST-treated mice compared with vehicle-treated mice. The mRNA and protein levels of eotaxin, MIF, IL-4, IL-5 and L-histidine decarboxylase were significantly decreased in the skin of AST-treated mice compared with vehicle-treated mice. These results suggest that AST improves the dermatitis and pruritus in AD via the regulation of the inflammatory effects and the expression of inflammatory cytokines.

  4. Global distribution, diversity hot spots and niche transitions of an astaxanthin-producing eukaryotic microbe.

    Science.gov (United States)

    David-Palma, Márcia; Libkind, Diego; Sampaio, José Paulo

    2014-02-01

    Microbes establish very diverse but still poorly understood associations with other microscopic or macroscopic organisms that do not follow the more conventional modes of competition or mutualism. Phaffia rhodozyma, an orange-coloured yeast that produces the biotechnologically relevant carotenoid astaxanthin, exhibits a Holarctic association with birch trees in temperate forests that contrasts with the more recent finding of a South American population associated with Nothofagus (southern beech) and with stromata of its biotrophic fungal parasite Cyttaria spp. We investigated whether the association of Phaffia with Nothofagus-Cyttaria could be expanded to Australasia, the other region of the world where Nothofagus are endemic, studied the genetic structure of populations representing the known worldwide distribution of Phaffia and analysed the evolution of the association with tree hosts. The phylogenetic analysis revealed that Phaffia diversity in Australasia is much higher than in other regions of the globe and that two endemic and markedly divergent lineages seem to represent new species. The observed genetic diversity correlates with host tree genera rather than with geography, which suggests that adaptation to the different niches is driving population structure in this yeast. The high genetic diversity and endemism in Australasia indicate that the genus evolved in this region and that the association with Nothofagus is the ancestral tree association. Estimates of the divergence times of Phaffia lineages point to splits that are much more recent than the break-up of Gondwana, supporting that long-distance dispersal rather than vicariance is responsible for observed distribution of P. rhodozyma. © 2014 John Wiley & Sons Ltd.

  5. Anti-inflammatory effect of Astaxanthin in phthalic anhydride-induced atopic dermatitis animal model.

    Science.gov (United States)

    Park, Ju Ho; Yeo, In Jun; Han, Ji Hye; Suh, Jeong Won; Lee, Hee Pom; Hong, Jin Tae

    2017-09-08

    In this study, we investigated anti-dermatitic effects of Astaxanthin (AST) in phthalic anhydride (PA)-induced atopic dermatitis (AD) animal model as well as in vitro model. AD-like lesion was induced by the topical application of 5% PA to the dorsal skin or ear of Hos:HR-1 mouse. After AD induction, 100 μl of 1 mg/ml and 2 mg/ml of AST (10 μg or 20 μg/cm(2) ) was spread on the dorsum of ear or back skin three times a week for four weeks. We evaluated dermatitis severity, histopathological changes and changes in protein expression by Western blotting for inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and nuclear factor-κB (NF-κB) activity. We also measured tumor necrosis factor- α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and immunoglobulinE (IgE) concentration in the blood of AD mice by enzyme-linked immunosorbent assay (ELISA). AST treatment attenuated the development of PA-induced AD. Histological analysis showed that AST inhibited hyperkeratosis, mast cells and infiltration of inflammatory cells. AST treatment inhibited expression of iNOS and COX-2, and NF-κB activity as well as release of TNF-α, IL-1β, IL-6, and IgE. In addition, AST (5, 10, and 20μM) potently inhibited lipopolysaccharide (LPS) (1 μg/ml)-induced nitric oxide (NO) production, expression of iNOS and COX-2, and NF-κB DNA binding activities in RAW 264.7 macrophage cells. Our data demonstrated that AST could be a promising agent for AD by inhibition of NF-κB signaling. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  6. Unphysical states in staggered chiral perturbation theory

    CERN Document Server

    Aubin, Christopher; Davila, George

    2015-01-01

    We study the extended phase diagram for staggered quarks using chiral perturbation theory. Recent beyond-the-standard-model simulations have shown that broken phases occur for coarse enough lattice spacing, so long as the number of quark flavors in the simulation is large enough (greater than eight). One of the phases seen in these simulations can be studied in depth using chiral perturbation theory. We also show that there are only three broken phases for staggered quarks that can arise, at least for lattice spacings in the regime a^2<< Lambda^2_{QCD}.

  7. Chiral Surface Waves for Enhanced Circular Dichroism

    CERN Document Server

    Pellegrini, Giovanni; Celebrano, Michele; Duò, Lamberto; Biagioni, Paolo

    2016-01-01

    We present a novel chiral sensing platform that combines a one-dimensional photonic crystal design with a birefringent surface defect. The platform sustains simultaneous transverse electric and transverse magnetic surface modes, which are exploited to generate chiral surface waves. The present design provides homogeneous and superchiral fields of both handednesses over arbitrarily large areas in a wide spectral range, resulting in the enhancement of the circular dichroism signal by two orders of magnitude, thus paving the road toward the successful combination of surface-enhanced spectroscopies and electromagnetic superchirality.

  8. Chiral edge fluctuations of colloidal membranes

    Science.gov (United States)

    Jia, Leroy; Zakhary, Mark; Dogic, Zvonimir; Pelcovits, Robert; Powers, Thomas

    Using experiments and theory we study chiral fluctuations of the edge of a nearly flat colloidal membrane, consisting of rod-like viruses held together by the depletion interaction. Our measurements show an anomalous peak in the power spectrum around 1 inverse micron. Using an effective theory to describe the liquid crystal degrees of freedom by geometric properties of the edge, such as length, geodesic torsion, and curvature, we calculate the spectrum of out-of-plane edge fluctuations. The peak arises for sufficiently strong chirality, and corresponds to the instability of a flat membrane to a shape with helical, rippled edges.

  9. Probing Chiral Interactions in Light Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Nogga, A; Barrett, B R; Meissner, U; Witala, H; Epelbaum, E; Kamada, H; Navratil, P; Glockle, W; Vary, J P

    2004-01-08

    Chiral two- and three-nucleon interactions are studied in a few-nucleon systems. We investigate the cut-off dependence and convergence with respect to the chiral expansion. It is pointed out that the spectra of light nuclei are sensitive to the three-nucleon force structure. As an example, we present calculations of the 1{sup +} and 3{sup +} states of {sup 6}Li using the no-core shell model approach. The results show contributions of the next-to-next-to-leading order terms to the spectra, which are not correlated to the three-nucleon binding energy prediction.

  10. Isotropic Chiral Objects With Zero Backscattering

    CERN Document Server

    Karilainen, Antti O

    2012-01-01

    In this paper we study electrically small chiral objects with isotropic response and zero backscattering. A bi-isotropic sphere is used as a simple example and its zero-backscattering conditions are studied. A theoretical model of an object composed of three orthogonal chiral particles made of conducting wire is presented as an analog of the zero-backscattering bi-isotropic sphere. A potential application of the object as a receiving antenna or a sensor with the ability to receive power from an arbitrary direction without backscattering is discussed.

  11. Heavy-tailed chiral random matrix theory

    Energy Technology Data Exchange (ETDEWEB)

    Kanazawa, Takuya [iTHES Research Group and Quantum Hadron Physics Laboratory, RIKEN,Wako, Saitama, 351-0198 (Japan)

    2016-05-27

    We study an unconventional chiral random matrix model with a heavy-tailed probabilistic weight. The model is shown to exhibit chiral symmetry breaking with no bilinear condensate, in analogy to the Stern phase of QCD. We solve the model analytically and obtain the microscopic spectral density and the smallest eigenvalue distribution for an arbitrary number of flavors and arbitrary quark masses. Exotic behaviors such as non-decoupling of heavy flavors and a power-law tail of the smallest eigenvalue distribution are illustrated.

  12. Heavy-tailed chiral random matrix theory

    Science.gov (United States)

    Kanazawa, Takuya

    2016-05-01

    We study an unconventional chiral random matrix model with a heavy-tailed probabilistic weight. The model is shown to exhibit chiral symmetry breaking with no bilinear condensate, in analogy to the Stern phase of QCD. We solve the model analytically and obtain the microscopic spectral density and the smallest eigenvalue distribution for an arbitrary number of flavors and arbitrary quark masses. Exotic behaviors such as non-decoupling of heavy flavors and a power-law tail of the smallest eigenvalue distribution are illustrated.

  13. Chiral pesticides: Identification, description, and environmental implications

    Science.gov (United States)

    Ulrich, Elin M.; Morrison, Candice N.; Goldsmith, Michael R.; Foreman, William T.

    2012-01-01

    Anthropogenic chemicals, including pesticides, are a major source of contamination and pollution in the environment. Pesticides have many positive uses: increased food production, decreased damage to crops and structures, reduced disease vector populations, and more. Nevertheless, pesticide exposure can pose risks to humans and the environment, so various mitigation strategies are exercised to make them safer, minimize their use, and reduce their unintended environment effects. One strategy that may help achieve these goals relies on the unique properties of chirality or molecular asymmetry. Some common terms related to chirality are defined in Table 1.

  14. Phenomenology of chiral damping in noncentrosymmetric magnets

    KAUST Repository

    Akosa, Collins Ashu

    2016-06-21

    A phenomenology of magnetic chiral damping is proposed in the context of magnetic materials lacking inversion symmetry. We show that the magnetic damping tensor acquires a component linear in magnetization gradient in the form of Lifshitz invariants. We propose different microscopic mechanisms that can produce such a damping in ferromagnetic metals, among which local spin pumping in the presence of an anomalous Hall effect and an effective “s-d” Dzyaloshinskii-Moriya antisymmetric exchange. The implication of this chiral damping in terms of domain-wall motion is investigated in the flow and creep regimes.

  15. Rotating optical microcavities with broken chiral symmetry

    CERN Document Server

    Sarma, Raktim; Wiersig, Jan; Cao, Hui

    2014-01-01

    We demonstrate in open microcavities with broken chiral symmetry, quasi-degenerate pairs of co-propagating modes in a non-rotating cavity evolve to counter-propagating modes with rotation. The emission patterns change dramatically by rotation, due to distinct output directions of CW and CCW waves. By tuning the degree of spatial chirality, we maximize the sensitivity of microcavity emission to rotation. The rotation-induced change of emission is orders of magnitude larger than the Sagnac effect, pointing to a promising direction for ultrasmall optical gyroscopes.

  16. Speciation and gene flow between snails of opposite chirality.

    Directory of Open Access Journals (Sweden)

    2005-09-01

    Full Text Available Left-right asymmetry in snails is intriguing because individuals of opposite chirality are either unable to mate or can only mate with difficulty, so could be reproductively isolated from each other. We have therefore investigated chiral evolution in the Japanese land snail genus Euhadra to understand whether changes in chirality have promoted speciation. In particular, we aimed to understand the effect of the maternal inheritance of chirality on reproductive isolation and gene flow. We found that the mitochondrial DNA phylogeny of Euhadra is consistent with a single, relatively ancient evolution of sinistral species and suggests either recent "single-gene speciation" or gene flow between chiral morphs that are unable to mate. To clarify the conditions under which new chiral morphs might evolve and whether single-gene speciation can occur, we developed a mathematical model that is relevant to any maternal-effect gene. The model shows that reproductive character displacement can promote the evolution of new chiral morphs, tending to counteract the positive frequency-dependent selection that would otherwise drive the more common chiral morph to fixation. This therefore suggests a general mechanism as to how chiral variation arises in snails. In populations that contain both chiral morphs, two different situations are then possible. In the first, gene flow is substantial between morphs even without interchiral mating, because of the maternal inheritance of chirality. In the second, reproductive isolation is possible but unstable, and will also lead to gene flow if intrachiral matings occasionally produce offspring with the opposite chirality. Together, the results imply that speciation by chiral reversal is only meaningful in the context of a complex biogeographical process, and so must usually involve other factors. In order to understand the roles of reproductive character displacement and gene flow in the chiral evolution of Euhadra, it will be

  17. Regulation of astaxanthin and its intermediates through cloning and genetic transformation of β-carotene ketolase in Haematococcus pluvialis.

    Science.gov (United States)

    Kathiresan, S; Chandrashekar, Arun; Ravishankar, G A; Sarada, R

    2015-02-20

    Astaxanthin, a high-value ketocarotenoid used in the pharmaceutical and nutraceutical industries is mainly produced from green alga, Haematococcus pluvialis. It is biosynthesized by the action of key enzyme, β-carotene ketolase (BKT) on β-carotene through intermediates echinenone and canthaxanthin. In this study, the β-carotene ketolase (bkt) gene was isolated from H. pluvialis and cloned in a vector pRT100 and further mobilized to a binary vector pCAMBIA 1304. The T-DNA of pCAMBIA 1304, which consists of cloned bkt, was successfully transformed to H. pluvialis through Agrobacterium mediation. The cloning and transformation of bkt in H. pluvialis was confirmed by Southern blotting and also by PCR analysis. Total carotenoids and astaxanthin content in the transformed cells were found to be 2-3-fold higher, while the intermediates like echinenone and canthaxanthin were found to be 8-10-fold higher than in the control cells. The expression level of carotenogenic genes like phytoene synthase (psy), phytoene desaturase (pds), lycopene cyclase (lcy), bkt, and β-carotene hydroxylase (bkh) were found to be higher in transformed cells compared to the non-transformed (NT) H. pluvialis. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Liquid Phases in SU(3) Chiral Perturbation Theory: Drops of Strange Chiral Nucleon Liquid & Ordinary Chiral Heavy Nuclear Liquid

    CERN Document Server

    Lynn, Bryan W.

    2010-01-01

    Chiral SU(3) Perturbation Theory (SU3XPT) identifies hadrons as the building blocks of strongly interacting matter at low densities and temperatures. We show that it admits two co-existing chiral nucleon liquid phases at zero external pressure with well-defined surfaces: 1) ordinary microscopic chiral heavy nuclear liquid drops (XNL) and 2) a new Strange Chiral Nucleon Liquid (SXNL) phase with both microscopic and macroscopic drop sizes. Liquid drops of both XNL and SXNL are simultaneously solutions to the SU3XPT semi-classical equations of motion and obey all relevant CVC and PCAC equations. Axial-vector currents are conserved inside macroscopic drops of SXNL, a new form of baryonic matter with zero electric charge density, which is by nature "dark". The numerical values of all SU3XPT coefficients are used to fit current scattering experiments and ordinary XNL drops (identified with the ground state of ordinary even-even spin-zero spherical closed-shell nuclei). SXNL then also emerges (i.e. without new adjus...

  19. Reactive oxygen species scavenging activities in a chemiluminescence model and neuroprotection in rat pheochromocytoma cells by astaxanthin, beta-carotene, and canthaxanthin

    Directory of Open Access Journals (Sweden)

    Chi-Sen Chang

    2013-08-01

    Full Text Available The objective of this study was to determine chemiluminescence (CL antioxidant activities and neuroprotective effects of astaxanthin, beta-carotene (β-carotene, and canthaxanthin on undifferentiated rat pheochromocytoma (PC12 cells. We performed three CL antioxidant assays, and the three carotenoids showed varying degrees of antioxidant activity, with astaxanthin exhibiting the highest antioxidant activity than the other two samples. Results of a pyrogallol–luminol assay revealed β-carotene to have higher antioxidant activity than canthaxanthin, whereas cupric sulfate–Phen–Vc–hydrogen peroxide (H2O2 assay showed canthaxanthin to have higher antioxidant activity than β-carotene. Luminol–H2O2 assay showed the antioxidant activity series as canthaxanthin > β-carotene at 62.5–1000 μg/mL and β-carotene > canthaxanthin at 1000–4000 μg/mL. Astaxanthin exhibited partial neuroprotective activity against H2O2 and the strongest neuroprotective activity against amyloid beta-peptide(25–35 [(Aβ(25–35]-induced undifferentiated PC12 cell deaths at 0.5–5.0 μM. Canthaxanthin showed partial neuroprotective activity in Aβ(25–35-induced undifferentiated PC12 cell deaths at 1.0–5.0 μM. Astaxanthin protected undifferentiated PC12 cells from the damaging effects of H2O2 and Aβ(25–35 by the following ways: (1 scavenging superoxide anion radicals, hydroxyl radicals, and H2O2; (2 securing cell viability; (3 suppressing the production of reactive oxygen species; and (4 eliminating calcium ion influx. Our results conclusively show that astaxanthin has the merit as a potential neuron protectant.

  20. Dietary values of astaxanthin and canthaxanthin in Penaeus monodon in the presence and absence of cholesterol supplementation: effect on growth, nutrient digestibility and tissue carotenoid composition.

    Science.gov (United States)

    Niu, Jin; Li, Chun-Hou; Liu, Yong-Jian; Tian, Li-Xia; Chen, Xu; Huang, Zhong; Lin, Hei-Zhao

    2012-07-14

    Penaeus monodon (mean initial wet weight 1·19 (SE 0·01) g) were fed seven diets in triplicate: a control diet (D1) without carotenoids; three diets formulated to supply 0·1 % astaxanthin alone (D2), 0·2 % astaxanthin alone (D3), and a combination of 0·1 % astaxanthin and 1 % cholesterol (D4); three diets with 0·07 % canthaxanthin alone (D5), 0·13 % canthaxanthin alone (D6), and a combination of 0·07 % canthaxanthin and 1 % cholesterol (D7). Weight gain (WG, %), specific growth rate (SGR, %/d) and survival were chosen as parameters of shrimp growth performance. Total antioxidant status (TAS), superoxide dismutase (SOD), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were chosen as indices of shrimp plasma antioxidant capacity. Meanwhile, digestibility, retention efficiency and tissue carotenoids were also investigated to determine the additive effect of cholesterol on the efficiency of astaxanthin and canthaxanthin. After 74 d rearing, WG and SGR of shrimp fed D2-D4 and D7 were higher than those of shrimp fed D1 (P 98 %) in D2-D4 and no differences were found among them (P>0·05), the carotenoid retention efficiencies in the whole body, muscle and shell (D2-D3 treatments) were considerably low; however, cholesterol supplementation significantly improved the carotenoid retention efficiencies in the whole body, muscle and shell (D4 treatment). Accordingly, the addition of cholesterol also significantly enhanced the carotenoid contents of tissues. Shrimp fed supplemented carotenoid diets (D2-D7) had higher TAS and lower SOD, ALT and AST than shrimp fed D1 (P cholesterol could positively enhance the efficiency of astaxanthin and canthaxanthin.

  1. HPLC SEPARATION OF CHIRAL ORGANOPHOSPHORUS PESTICIDES ON POLYSACCHARIDE CHIRAL STATIONARY PHASES

    Science.gov (United States)

    High-performance liquid chromatographic separation of the individual enantiomers of 12 organophosphorus pesticides (OPs) were obtained on polysaccharide chiral HPLC columns using an alkane-alcohol mobile phase. The OP pesticides were crotoxyphos, dialifor, dyfonate, fenamiphos, ...

  2. Chiral vortical effect generated by chiral anomaly in vortex-skyrmions

    Science.gov (United States)

    Volovik, G. E.

    2017-03-01

    We discuss the type of the general macroscopic parity-violating effects, when there is the current along the vortex, which is concentrated in the vortex core. We consider vortices in chiral superfluids with Weyl points. In the vortex core, the positions of the Weyl points form the skyrmion structure. We show that the mass current concentrated in such a core is provided by the spectral flow through the Weyl points according to the Adler-Bell-Jackiw equation for chiral anomaly.

  3. Synthesis of Chiral Building Blocks for Use in Drug Discovery

    Directory of Open Access Journals (Sweden)

    Rustum S. Boyce

    2004-05-01

    Full Text Available In the past decade there has been a significant growth in the sales of pharmaceutical drugs worldwide, but more importantly there has been a dramatic growth in the sales of single enantiomer drugs. The pharmaceutical industry has a rising demand for chiral intermediates and research reagents because of the continuing imperative to improve drug efficacy. This in turn impacts on researchers involved in preclinical discovery work. Besides traditional chiral pool and resolution of racemates as sources of chiral building blocks, many new synthetic methods including a great variety of catalytic reactions have been developed which facilitate the production of complex chiral drug candidates for clinical trials. The most ambitious technique is to synthesise homochiral compounds from non-chiral starting materials using chiral metal catalysts and related chemistry. Examples of the synthesis of chiral building blocks from achiral materials utilizing asymmetric hydrogenation and asymmetric epoxidation are presented.

  4. Chiral spiral induced by a strong magnetic field

    Directory of Open Access Journals (Sweden)

    Abuki Hiroaki

    2016-01-01

    Full Text Available We study the modification of the chiral phase structure of QCD due to an external magnetic field. We first demonstrate how the effect of magnetic field can systematically be incorporated into a generalized Ginzburg-Landau framework. We then analyze the phase structure in the vicinity of the chiral critical point. In the chiral limit, the effect is found to be so drastic that it brings a “continent” of chiral spiral in the phase diagram, by which the chiral tricritical point is totally washed out. This is the case no matter how small the intensity of magnetic field is. On the other hand, the current quark mass protects the chiral critical point from a weak magnetic field. However, the critical point will eventually be covered by the chiral spiral phase as the magnetic field grows.

  5. Synthesis and biological evaluation of the four isomers of technetium-99m labeled ethylenecysteamine cysteine ({sup 99m}Tc-ECC), the mono-acid derivative of {sup 99m}tc-L,L-ethylenedicysteine

    Energy Technology Data Exchange (ETDEWEB)

    Vanbilloen, Hubert P.; Cleynhens, Bernard J.; Verbruggen, Alfons M. E-mail: alfons.verbruggen@uz.kuleuven.ac.be

    2000-02-01

    A few years ago {sup 99m}Tc-ethylenedicysteine ({sup 99m}Tc-L,L-EC) had been proposed as an interesting substitute for technetium-99m labeled mercaptoacetyltriglycine (MAG3) as renal function tracer agent. It possesses in its structure two carboxylate functions and is in this respect different from other renal tracers such as {sup 99m}Tc-N,N'-bis-(mercaptoacetyl)-2,3-diaminopropionate ({sup 99m}Tc-CO{sub 2}DADS), {sup 99m}Tc-MAG3, and Hippuran, which have only one carboxylic group. To study whether both carboxylic acid groups of {sup 99m}Tc-L,L-EC contribute to the efficient renal handling of this compound we synthesized and biologically evaluated the technetium-99m labeled isomers of L- and D-ethylenecysteamine cysteine (ECC), the mono-acid derivative of {sup 99m}Tc-L,L-EC. Labeling of L-ECC or D-ECC with {sup 99m}Tc using a direct or exchange labeling method yields for each of them two diastereomeric {sup 99m}Tc complexes (A and B, in the order of elution during reversed phase high performance liquid chromatography) in relative amounts depending on the pH during labeling. In mice, all four isomers of {sup 99m}Tc-ECC (LA, LB, DA, and DB) are cleared rapidly from the blood, mainly by the renal system. The isomers LB and DB show the most efficient renal handling, but none of the mono-acid derivatives has a urinary excretion rate as high as that of {sup 99m}Tc-L,L-EC. The renal handling of the isomers of {sup 99m}Tc-ECC is partly due to tubular secretion because the urinary excretion of these compounds is significantly lower in mice pretreated with probenecid. In the baboon, isomers DA and DB show a plasma clearance comparable to that of {sup 99m}Tc-L,L-EC. The plasma clearance of isomers LA and LB is lower but still comparable to or higher than that of {sup 99m}Tc-MAG3. In a human volunteer, isomer DB shows a plasma clearance rate only slightly lower than that of {sup 99m}Tc-L,L-EC. Thus, it appears that the presence of one carboxylate in {sup 99m

  6. Supramolecular Nanostructures of Chiral Perylene Diimides with Amplified Chirality for High-Performance Chiroptical Sensing.

    Science.gov (United States)

    Shang, Xiaobo; Song, Inho; Ohtsu, Hiroyoshi; Lee, Yoon Ho; Zhao, Tianming; Kojima, Tatsuhiro; Jung, Ji Hyung; Kawano, Masaki; Oh, Joon Hak

    2017-06-01

    Chiral supramolecular nanostructures with optoelectronic functions are expected to play a central role in many scientific and technological fields but their practical use remains in its infancy. Here, this paper reports photoconductive chiral organic semiconductors (OSCs) based on perylene diimides with the highest electron mobility among the chiral OSCs and investigates the structure and optoelectronic properties of their homochiral and heterochiral supramolecular assemblies from bottom-up self-assembly. Owing to the well-ordered supramolecular packing, the homochiral nanomaterials exhibit superior charge transport with significantly higher photoresponsivity and dissymmetry factor compared with those of their thin film and monomeric equivalents, which enables highly selective detection of circularly polarized light, for the first time, in visible spectral range. Interestingly, the heterochiral nanostructures assembled from co-self-assembly of racemic mixtures show extraordinary chiral self-discrimination phenomenon, where opposite enantiomeric molecules are packed alternately into heterochiral architectures, leading to completely different optoelectrical performances. In addition, the crystal structures of homochiral and heterochiral nanostructures have first been studied by ab initio X-ray powder diffraction analysis. These findings give insights into the structure-chiroptical property relationships of chiral supramolecular self-assemblies and demonstrate the feasibility of supramolecular chirality for high-performance chiroptical sensing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Chiral symmetry breaking and chiral polarization: Tests for finite temperature and many flavors

    Directory of Open Access Journals (Sweden)

    Andrei Alexandru

    2015-02-01

    Full Text Available It was recently conjectured that, in SU(3 gauge theories with fundamental quarks, valence spontaneous chiral symmetry breaking is equivalent to condensation of local dynamical chirality and appearance of chiral polarization scale Λch. Here we consider more general association involving the low-energy layer of chirally polarized modes which, in addition to its width (Λch, is also characterized by volume density of participating modes (Ω and the volume density of total chirality (Ωch. Few possible forms of the correspondence are discussed, paying particular attention to singular cases where Ω emerges as the most versatile characteristic. The notion of finite-volume “order parameter”, capturing the nature of these connections, is proposed. We study the effects of temperature (in Nf=0 QCD and light quarks (in Nf=12, both in the regime of possible symmetry restoration, and find agreement with these ideas. In Nf=0 QCD, results from several volumes indicate that, at the lattice cutoff studied, the deconfinement temperature Tc is strictly smaller than the overlap–valence chiral transition temperature Tch in real Polyakov line vacuum. Somewhat similar intermediate phase (in quark mass is also seen in Nf=12. It is suggested that deconfinement in Nf=0 is related to indefinite convexity of absolute X-distributions.

  8. From Ostwald Ripening to Single Chirality

    NARCIS (Netherlands)

    Noorduin, Wim L.; Vlieg, Elias; Kellogg, Richard M.; Kaptein, Bernard

    2009-01-01

    A century ago Wilhelm Ostwald received the Nobel Prize for Chemistry. Although Ostwald was never significantly involved with the phenomenon of chirality, one of his discoveries, Ostwald ripening, is thought to be involved in a recently discovered method in which grinding-induced attrition is used to

  9. Chiral damping of magnetic domain walls

    KAUST Repository

    Jué, Emilie

    2015-12-21

    Structural symmetry breaking in magnetic materials is responsible for the existence of multiferroics1, current-induced spin–orbit torques2, 3, 4, 5, 6, 7 and some topological magnetic structures8, 9, 10, 11, 12. In this Letter we report that the structural inversion asymmetry (SIA) gives rise to a chiral damping mechanism, which is evidenced by measuring the field-driven domain-wall (DW) motion in perpendicularly magnetized asymmetric Pt/Co/Pt trilayers. The DW dynamics associated with the chiral damping and those with Dzyaloshinskii–Moriya interaction (DMI) exhibit identical spatial symmetry13, 14, 15, 16, 17, 18, 19. However, both scenarios are differentiated by their time reversal properties: whereas DMI is a conservative effect that can be modelled by an effective field, the chiral damping is purely dissipative and has no influence on the equilibrium magnetic texture. When the DW motion is modulated by an in-plane magnetic field, it reveals the structure of the internal fields experienced by the DWs, allowing one to distinguish the physical mechanism. The chiral damping enriches the spectrum of physical phenomena engendered by the SIA, and is essential for conceiving DW and skyrmion devices owing to its coexistence with DMI (ref. 20).

  10. Optimization of enantioselective production of chiral epichlorohydrin ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    Oct 19, 2009 ... Kinetic resolution for optically active epoxides by microbial enantioselective hydrolysis. Biotechnol. Tech. 12: 225-228. Choi WJ, Lee EY, Yoon SJ, Yang ST, Choi CY (1999). Biocatalytic production of chiral epichlorohydrin in organic solvents. J. Biosci. Bioeng. 88: 339-341. De Vries EJ, Janssen DB (2003).

  11. Wave propagation retrieval method for chiral metamaterials

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Lavrinenko, Andrei

    2010-01-01

    In this paper we present the wave propagation method for the retrieving of effective properties of media with circularly polarized eigenwaves, in particularly for chiral metamaterials. The method is applied for thick slabs and provides bulk effective parameters. Its strong sides are the absence...

  12. Chiral perturbation theory and nucleon polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Babusci, D.; Giordano, G.; Matone, G. [INFN, Laboratori Nazionali di Frascati, Rome (Italy)

    1996-10-01

    The available experimental data concerning the unpolarized cross section for the Compton scattering on the nucleon at low energy are compared with the predictions of the heavy baryon chiral perturbation theory (HBChPT) at the order q{sup 3}.

  13. Insights on some chiral smectic phases

    Indian Academy of Sciences (India)

    journal of. August 2003 physics pp. 285–295. Insights on some chiral smectic phases. B PANSU. Laboratoire de Physique des Solides, Bt 510, UMR 8502, Universit ..... volve complex organizations of small SmCA grains, small meaning that the width of each grain is ... The colours of the platelets are due to low birefringence.

  14. Functional polypedes—chiral nematic fullerenes

    OpenAIRE

    Campidelli, Stéphane; Eng, Carine; Saez, Isabel M.; Goodby, John W.; Deschenaux, Robert

    2006-01-01

    Self-organising, functional materials created by bottom-up synthesis represent important steps forward in the development of novel materials, here we report on the preparation and properties of a chiral nematic tetrapedal liquid crystal that has been functionalised with C60.

  15. Quantization of massive chiral electrodynamics reexamined

    Energy Technology Data Exchange (ETDEWEB)

    Fosco, C.; Montemayor, R. (Centro Atomico Bariloche, Comision Nacional de Energia Atomica and Instituto Balseiro, Universidad Nacional de Cuyo, 8400 San Carlos de Bariloche, Rio Negro (Argentina))

    1993-05-15

    We show that the models considered by Andrianov [ital et] [ital al]. [Phys. Rev. Lett. 63, 1554 (1989); and Phys. Rev. D 44, 2602 (1991)] are equivalent to other models where it is easily proved that the anomaly decouples and consequently the value of the chiral triangles amplitude is irrelvant for the unitarity of the [ital S] matrix.

  16. Polar Superhelices in Ferroelectric Chiral Nanosprings

    Science.gov (United States)

    Shimada, Takahiro; Lich, Le Van; Nagano, Koyo; Wang, Jian-Shan; Wang, Jie; Kitamura, Takayuki

    2016-10-01

    Topological objects of nontrivial spin or dipolar field textures, such as skyrmions, merons, and vortices, interacting with applied external fields in ferroic materials are of great scientific interest as an intriguing playground of unique physical phenomena and novel technological paradigms. The quest for new topological configurations of such swirling field textures has primarily been done for magnets with Dzyaloshinskii-Moriya interactions, while the absence of such intrinsic chiral interactions among electric dipoles left ferroelectrics aside in this quest. Here, we demonstrate that a helical polarization coiled into another helix, namely a polar superhelix, can be extrinsically stabilized in ferroelectric nanosprings. The interplay between dipolar interactions confined in the chiral geometry and the complex strain field of mixed bending and twisting induces the superhelical configuration of electric polarization. The geometrical structure of the polar superhelix gives rise to electric chiralities at two different length scales and the coexistence of three order parameters, i.e., polarization, toroidization, and hypertoroidization, both of which can be manipulated by homogeneous electric and/or mechanical fields. Our work therefore provides a new geometrical configuration of swirling dipolar fields, which offers the possibility of multiple order-parameters, and electromechanically controllable dipolar chiralities and associated electro-optical responses.

  17. Dihyperons in chiral color dielectric model

    Indian Academy of Sciences (India)

    The mass of the dibaryon having spin, parity =0+, isospin = 0 and strangeness -2 is computed using chiral color dielectric model. The bare wave function is constructed as a product of two color-singlet three-quark clusters and then it is properly antisymmetrized by considering appropriate exchange operators for spin, ...

  18. ISOSPIN BREAKING AND THE CHIRAL CONDENSATE.

    Energy Technology Data Exchange (ETDEWEB)

    CREUTZ, M.

    2005-07-25

    With two degenerate quarks, the chiral condensate exhibits a jump as the quark masses pass through zero. I discuss how this single transition splits into two Ising like transitions when the quarks are made non-degenerate. The order parameter is the expectation of the neutral pion field. The transitions represent long distance coherent phenomena occurring without the Dirac operator having vanishingly small eigenvalues.

  19. Topological Order in Spin Liquids with Chirality

    OpenAIRE

    Scharfenberger, Burkhard

    2011-01-01

    We use the Kalmeyer-Laughlin Chiral Spin Liquid as building block to construct a hierarchy of higher-spin spin liquids and determine numerically their topological properties. We compute the entanglement spectra of some of these liquids as well as of ground states of critically frustrated quantum magnets. From the comparison, we find preliminary evidence for a topological phase transition in these systems.

  20. An Isomer-Specific Approach to Endocrine-Disrupting Nonylphenol in Infant Food.

    Science.gov (United States)

    Günther, Klaus; Räcker, Torsten; Böhme, Roswitha

    2017-02-15

    Nonylphenols (NPs) are persistent endocrine disruptors that are priority hazardous substances of the European Union Water Framework Directive. Their presence in the environment has caused growing concern regarding their impact on human health. Recent studies have shown that nonylphenol is ubiquitous in commercially available foodstuffs and is also present in human blood. The isomer distribution of 4-nonylphenol was analyzed by gas chromatography - mass spectrometry in 44 samples of infant food. Our study shows that the distribution of nonylphenol isomers is dependent on the foodstuff analyzed. Although some isomer groups prevail, different distributions are frequent. Variations are even found in the same food group. Nonylphenol is a complex mixture of isomers, and the estrogenic potentials of each of these isomers are very different. Consequently, to determine the potential toxicological impact of NP in food, an isomer-specific approach is necessary.

  1. Nuclear states with anomalously large radius (size isomers)

    Energy Technology Data Exchange (ETDEWEB)

    Ogloblin, A. A.; Demyanova, A. S., E-mail: a.s.demyanova@bk.ru; Danilov, A. N. [National Research Center Kurchatov Institute (Russian Federation); Belyaeva, T. L. [Ciudad Universitaria, Universidad Nacional Autónoma de Meéxico (Mexico); Goncharov, S. A. [Moscow State University, Faculty of Physics (Russian Federation); Trzaska, W. [University of Jyvaäskylaä (Finland)

    2016-07-15

    Methods of determination of the nuclear excited state radii are discussed together with the recently obtained data on the states of some light nuclei having abnormally large radii (size isomers). It is shown that such states include excited neutron-halo states in {sup 9}Be, {sup 11}Be, and {sup 13}C and some alpha-cluster states in {sup 12}C, {sup 11}B, and {sup 13}C. Among the latter ones, there is the well-known Hoyle state in {sup 12}C—the structure of this state exhibit rudimentary features of alpha-particle states.

  2. Nuclear chirality, a model and the data

    Science.gov (United States)

    Starosta, K.; Koike, T.

    2017-09-01

    In the last decade, the manifestation of chirality in atomic nuclei has become the subject of numerous experimental and theoretical studies. The common feature of current model calculations is that the chiral geometry of angular momentum coupling is extracted from expectation values of orientation operators, rather than being a starting point in construction of a model. However, using the particle-hole coupling model for triaxial odd-odd nuclei it is possible to construct a basis which contains right-handed, left-handed and planar states of angular momentum coupling. If this basis is used, the chirality is an explicit rather than an extracted feature as in any other models with non-chiral bases. The time-reversal symmetry, which relates the basis states of opposite handedness, can be used to reduce the dimension of matrices for diagonalization of the model Hamiltonian, proving the effectiveness of this approach. Moreover, the final model eigenstate wave functions show a concentration of amplitudes among a relatively small number (˜1%) of components compared to the full model space. In that sense, the ‘chiral’ basis provides a useful tool to examine model predictions providing direct insight into the structure of doublet states. In this work, similarities and differences between the rotational behaviour of an axial and triaxial body provide a starting point for derivation of the basis optimal for valence nucleon coupling to an axial and a triaxial core. The derived ‘chiral’ basis is optimal for coupling of a valence particle and hole to the triaxial core. Model predictions are presented and discussed. A comprehensive review of current experimental data on observed chiral band candidates is also provided.

  3. A preliminary investigation of the enzymatic inhibition of 5alpha-reduction and growth of prostatic carcinoma cell line LNCap-FGC by natural astaxanthin and Saw Palmetto lipid extract in vitro.

    Science.gov (United States)

    Anderson, Mark L

    2005-01-01

    Inhibition of 5alpha-reductase has been reported to decrease the symptoms of benign prostate hyperplasia (BPH) and possibly inhibit or help treat prostate cancer. Saw Palmetto berry lipid extract (SPLE) is reported to inhibit 5alpha-reductase and decrease the clinical symptoms of BPH. Epidemiologic studies report that carotenoids such as lycopene may inhibit prostate cancer. In this investigation the effect of the carotenoid astaxanthin, and SPLE were examined for their effect on 5alpha-reductase inhibition as well as the growth of prostatic carcinoma cells in vitro. These studies support patent #6,277,417 B1. The results show astaxanthin demonstrated 98% inhibition of 5alpha-reductase at 300 microg/mL in vitro. Alphastat, the combination of astaxanthin and SPLE, showed a 20% greater inhibition of 5alpha-reductase than SPLE alone n vitro. A nine day treatment of prostatic carcinoma cells with astaxanthin in vitro produced a 24% decrease in growth at 0.1 mcg/mL and a 38% decrease at 0.01 mcg/mL. SPLE showed a 34% decrease at 0.1 mcg/mL. Low levels of carotenoid astaxanthin inhibit 5alpha-reductase and decrease the growth of human prostatic cancer cells in vitro. Astaxanthin added to SPLE shows greater inhibition of 5alpha-reductase than SPLE alone in vitro.

  4. Identifying isomers of C-78 by means of x-ray spectroscopy

    DEFF Research Database (Denmark)

    Bassan, Arianna; Nyberg, Mats; Luo, Yi

    2002-01-01

    X-ray photoelectron and absorption spectra of C-78 isomers have been generated using density functional theory with inclusion of the full core-hole potentials. Strong isomer dependence has been found in absorption, but not in the photoelectron spectra. C-78 isomers can be thought to be formed by ...... by inserting 18 carbon atoms into an opened C-60. We have shown how the different local arrangements of these 18 carbon atoms are responsible for the significant isomer dependence observed. Our calculated spectra are in excellent agreement with the experimental counterparts....

  5. Effects of astaxanthin on blood coagulation, fibrinolysis and platelet aggregation in hyperlipidemic rats.

    Science.gov (United States)

    Deng, Zu-Yue; Shan, Wei-Guang; Wang, Shen-Feng; Hu, Meng-Mei; Chen, Yan

    2017-12-01

    Astaxanthin (ASTX) is a xanthophyll carotenoid that reduces hemostasis in hyperlipidemic organisms. Its antihemostatic mechanisms remain unclear. The effects of ASTX on coagulation, the fibrinolytic system and platelet aggregation were investigated in hyperlipidemic rats. Different doses of ASTX (5, 10 and 30 mg/kg/day, p.o.) were administered for four weeks to high-fat diet-induced hyperlipidemic rats. Serum lipid and lipoprotein levels were measured with an automatic biochemical analyzer. The prothrombin time (PT), activated partial thromboplastin time (APTT) and maximum platelet aggregation rate (MAR) were determined by a coagulation analyzer. The activities of the tissue-type plasminogen activator (t-PA), type-1 plasminogen activator inhibitor (PAI-1) and endothelial nitric oxide synthase (eNOS), as well as the levels of thromboxane B(2) [TXB(2)], 6-keto prostaglandin F(1α) [6-keto-PGF(1α)] and platelet granule membrane protein (GMP-140), were measured with enzyme-linked immunosorbent assay kits. Gene and protein expression levels were analyzed by reverse transcriptase polymerase chain reaction and Western blot, respectively. ASTX (30 mg/kg) treatment in hyperlipidemic rats reduced serum TG (0.58 ± 0.14 versus 1.12 ± 0.24 mmol/L), serum TC (1.77 ± 0.22 versus 2.24 ± 0.21 mmol/L), serum LDL-C (1.13 ± 0.32 versus 2.04 ± 0.48 mmol/L), serum MDA (69%), plasma MAR (55%), serum TXB2/6-keto-PGF1α (34%) and serum GMP-140 levels (25%), plasma PAI-1 activity (48%) and downregulated the mRNA (33%) and protein (23%) expression of aorta eNOS, the mRNA (79%) and protein (72%) expression levels of aorta PAI-1. However, ASTX (30 mg/kg/d) treatment increased serum SOD activity (2.1 fold), serum GPx activity (1.8 fold), plasma PT (1.3 fold), plasma APTT (1.7 fold), serum NO (1.4-fold), serum 6-keto-PGF1α (1.3 fold). ASTX reduced blood coagulation and platelet aggregation and promoted fibrinolytic activity in hyperlipidemic rats

  6. Baryons in the chiral regime

    Energy Technology Data Exchange (ETDEWEB)

    Knippschild, Bastian

    2012-03-05

    Quantum Chromodynamics (QCD) is the theory of strong interactions, one of the four fundamental forces in our Universe. It describes the interaction of gluons and quarks which build up hadrons like protons and neutrons. Most of the visible matter in our universe is made of protons and neutrons. Hence, we are interested in their fundamental properties like their masses, their distribution of charge and their shape. The only known theoretical, non-perturbative and ab initio method to investigate hadron properties at low energies is lattice Quantum Chromodynamics (lattice QCD). However, up-to-date simulations (especially for baryonic quantities) do not achieve the accuracy of experiments. In fact, current simulations do not even reproduce the experimental values for the form factors. The question arises wether these deviations can be explained by systematic effects in lattice QCD simulations. This thesis is about the computation of nucleon form factors and other hadronic quantities from lattice QCD. So called Wilson fermions are used and the u- and d-quarks are treated fully dynamically. The simulations were performed using gauge ensembles with a range of lattice spacings, volumes and pion masses. First of all, the lattice spacing was set to be able to make contact between the lattice results and their experimental complement and to be able to perform a continuum extrapolation. The light quark mass has been computed and found to be m{sub ud}{sup MS}(2 GeV)=3.03(17)(38) MeV. This value is in good agreement with values from experiments and other lattice determinations. Electro-magnetic and axial form factors of the nucleon have been calculated. From these form factors the nucleon radii and the coupling constants were computed. The different ensembles enabled us to investigate systematically the dependence of these quantities on the volume, the lattice spacing and the pion mass. Finally we perform a continuum extrapolation and chiral extrapolations to the physical point

  7. Developing chiral-technologies. Chiral technology that Alice in the mirror land gave a birth to; Hattensuru kiraru technology. Kagami no kuni no Alice ga unda kiraru technology

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, T. [Kanegafuchi Chemical Industry Co. Ltd., Osaka (Japan)

    1998-05-01

    Since the theory for optical isomers has been advocated by Van`t Hoff et al, studies were developed on correlation between structures and functions of optically active bodies through separation of 1-tartaric acid by Pasteur. Technologies to create freely the optically active bodies has contributed to advancement of chemistry. This paper describes improvement in the method of manufacturing D-amino acid by using biomass. Kaneka Co., Ltd. uses an enzyme method to produce D-parahydroxyphenylglycin (D-HPG) which is an important chiral block in manufacturing amoxicillin, a constituent substance. Its prescription is represented by a method to covert hydantoin compound of racemic modification into D-amino acid through hydrolysis by utilizing two kinds of enzymes. Heat resistance was imparted to elevate stability of the parent decarbamylase. The decarbamylase genes originated from the 712 bacteria were introduced into a phage, which were randomly mutated by using a mutant. These mutated genes were introduced into colibacilli to select bacteria having decarbamylase whose heat resistance was increased by using recombined colibacilli. 2 refs., 2 figs., 3 tabs.

  8. Molecular-Level Design of Heterogeneous Chiral Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Francisco Zaera

    2012-03-21

    The following is a proposal to continue our multi-institutional research on heterogeneous chiral catalysis. Our team combines the use of surface-sensitive analytical techniques for the characterization of model systems with quantum and statistical mechanical calculations to interpret experimental data and guide the design of future research. Our investigation focuses on the interrelation among the three main mechanisms by which enantioselectivity can be bestowed to heterogeneous catalysts, namely: (1) by templating chirality via the adsorption of chiral supramolecular assemblies, (2) by using chiral modifiers capable of forming chiral complexes with the reactant and force enantioselective surface reactions, and (3) by forming naturally chiral surfaces using imprinting chiral agents. Individually, the members of our team are leaders in these various aspects of chiral catalysis, but the present program provides the vehicle to generate and exploit the synergies necessary to address the problem in a comprehensive manner. Our initial work has advanced the methodology needed for these studies, including an enantioselective titration procedure to identify surface chiral sites, infrared spectroscopy in situ at the interface between gases or liquids and solids to mimic realistic catalytic conditions, and DFT and Monte Carlo algorithms to simulate and understand chirality on surfaces. The next step, to be funded by the monies requested in this proposal, is to apply those methods to specific problems in chiral catalysis, including the identification of the requirements for the formation of supramolecular surface structures with enantioselective behavior, the search for better molecules to probe the chiral nature of the modified surfaces, the exploration of the transition from supramolecular to one-to-one chiral modification, the correlation of the adsorption characteristics of one-to-one chiral modifiers with their physical properties, in particular with their configuration

  9. Astaxanthin treatment confers protection against oxidative stress in U937 cells stimulated with lipopolysaccharide reducing O2- production.

    Directory of Open Access Journals (Sweden)

    Sara Franceschelli

    Full Text Available Recently, astaxanthin (ASTA studies have focused on several biological functions such as radical scavenging, singlet oxygen quenching, anti-carcinogenesis, anti-diabetic, anti-obesity, anti-inflammatory, anti-melanogenesis, and immune enhancement activities. In this study, we investigated the potential role protective of ASTA, an antioxidant marine carotenoid, in restoring physiological conditions in U937 cells stimulated with LPS (10 µg/ml. Our results show that pre-treatment with ASTA (10 µM for 1 h attenuates the LPS-induced toxicity and ROS production. The beneficial effect of ASTA is associated with a reduction intracellular O2 (- production by restoring the antioxidant network activity of superoxide dismutase (SOD and catalase (CAT, which influence HO-1 expression and activity by inhibiting nuclear translocation of Nrf2. We accordingly hypothesize that ASTA has therapeutic properties protecting U937 cells from LPS-induced inflammatory and oxidative stress.

  10. Chiral assembly of weakly curled hard rods: Effect of steric chirality and polarity

    Energy Technology Data Exchange (ETDEWEB)

    Wensink, H. H., E-mail: wensink@lps.u-psud.fr; Morales-Anda, L. [Laboratoire de Physique des Solides–UMR 8502, Université Paris-Sud & CNRS, 91405 Orsay (France)

    2015-10-14

    We theoretically investigate the pitch of lyotropic cholesteric phases composed of slender rods with steric chirality transmitted via a weak helical deformation of the backbone. In this limit, the model is amenable to analytical treatment within Onsager theory and a closed expression for the pitch versus concentration and helical shape can be derived. Within the same framework, we also briefly review the possibility of alternative types of chiral order, such as twist-bend or screw-like nematic phases, finding that cholesteric order dominates for weakly helical distortions. While long-ranged or “soft” chiral forces usually lead to a pitch decreasing linearly with concentration, steric chirality leads to a much steeper decrease of quadratic nature. This reveals a subtle link between the range of chiral intermolecular interaction and the pitch sensitivity with concentration. A much richer dependence on the thermodynamic state is revealed for polar helices where parallel and anti-parallel pair alignments along the local director are no longer equivalent. It is found that weak temperature variations may lead to dramatic changes in the pitch, despite the lyotropic nature of the assembly.

  11. Electromagnetic wave propagation through a dielectric-chiral interface and through a chiral slab

    Science.gov (United States)

    Bassiri, S.; Papas, C. H.; Engheta, N.

    1988-01-01

    The reflection from and transmission through a semiinfinite chiral medium are analyzed by obtaining the Fresnel equations in terms of parallel- and perpendicular-polarized modes, and a comparison is made with results reported previously. The chiral medium is described electromagnetically by the constitutive relations D = (epsilon)E+i(gamma)B and H = i(gamma)E+(1/mu)B. The constants epsilon, mu and gamma are real and have values that are fixed by the size, the shape, and the spatial distribution of the elements that collectively compose the medium. The conditions are obtained for the total internal reflection of the incident wave from the interface and for the existence of the Brewster angle. The effects of the chirality on the polarization and the intensity of the reflected wave from the chiral half-space are discussed and illustrated by using the Stokes parameters. The propagation of electromagnetic wave through an infinite slab of chiral medium is formulated for oblique incidence and solved analytically for the case of normal incidence.

  12. Chiral separation of new designer drugs (Cathinones) on chiral ion-exchange type stationary phases.

    Science.gov (United States)

    Wolrab, Denise; Frühauf, Peter; Moulisová, Alena; Kuchař, Martin; Gerner, Christopher; Lindner, Wolfgang; Kohout, Michal

    2016-02-20

    We present the enantioseparation of new designer drugs from the cathinone family on structurally different chiral ion-exchange type stationary phases. A novel strong cation-exchange type chiral stationary phase was synthesized and its performance compared with previously reported ion-exchange type chiral stationary phases. The influence of structural elements of the chiral selectors on their chromatographic performance was studied and the possibilities of tuning chromatographic parameters by varying the polarity of the employed mobile phases were determined. Evidence is provided that a change in mobile phase composition strongly influences the solvation shell of the polarized and polarizable units of the selectors and analytes, as well as ionizable mobile phase additives. Furthermore, the structural features of the selectors (e.g. the size of aromatic units and their substitution pattern) are shown to play a key role in the effective formation of diastereomeric complexes with analytes. Thus, we have achieved the enantioseparation of all test analytes with a mass spectrometry-compatible mobile phase with a chiral strong cation-exchange type stationary phase. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Amino acid ionic liquids as chiral ligands in ligand-exchange chiral separations.

    Science.gov (United States)

    Liu, Qian; Wu, Kangkang; Tang, Fei; Yao, Lihua; Yang, Fei; Nie, Zhou; Yao, Shouzhuo

    2009-09-28

    Recently, amino acid ionic liquids (AAILs) have attracted much research interest. In this paper, we present the first application of AAILs in chiral separation based on the chiral ligand exchange principle. By using 1-alkyl-3-methylimidazolium L-proline (L-Pro) as a chiral ligand coordinated with copper(II), four pairs of underivatized amino acid enantiomers-dl-phenylalanine (dl-Phe), dl-histidine (dl-His), dl-tryptophane (dl-Trp), and dl-tyrosine (dl-Tyr)-were successfully separated in two major chiral separation techniques, HPLC and capillary electrophoresis (CE), with higher enantioselectivity than conventionally used amino acid ligands (resolution (R(s))=3.26-10.81 for HPLC; R(s)=1.34-4.27 for CE). Interestingly, increasing the alkyl chain length of the AAIL cation remarkably enhanced the enantioselectivity. It was inferred that the alkylmethylimidazolium cations and L-Pro form ion pairs on the surface of the stationary phase or on the inner surface of the capillary. The ternary copper complexes with L-Pro are consequently attached to the support surface, thus inducing an ion-exchange type of retention for the dl-enantiomers. Therefore, the AAIL cation plays an essential role in the separation. This work demonstrates that AAILs are good alternatives to conventional amino acid ligands for ligand-exchange-based chiral separation. It also reveals the tremendous application potential of this new type of task-specific ILs.

  14. Manipulating the Lorentz force via the chirality of nanoparticles

    Science.gov (United States)

    Wang, Maoyan; Li, Hailong; Dong, Yuliang; Zhang, Xiaochuan; Du, Ming; Wang, Rui; Xu, Tong; Wu, Jian

    2016-12-01

    We demonstrate that a single plane wave pulls a chiral nanoparticle toward the light source. The nanoparticle exhibits optical gain in a particular wavelength region. The equivalence of the generalized and alternative expressions of the Lorentz force density relating to bound charges for chiral media is numerically validated. By considering the two-dimensional electromagnetic problem of incident plane waves normally impinged on active chiral cylinders, it is shown that the gradient force is mainly contributed by the bound electric and magnetic current densities of the cross-polarized waves. We also investigate how the medium parameters and impedance mismatch can be used to manipulate the pulling or pushing Lorentz forces between two chiral cylinders. This finding may provide a recipe to understand the light interaction with multiple chiral nanoparticles of arbitrary shapes (in general) with the aid of the numerical approach. It could be a promising avenue in controlling the optical micromanipulation for chiral nanoparticles with mirroring asymmetry.

  15. Enhanced Electromagnetic Chirality by Locally Excited Surface Plasmon Polaritons

    CERN Document Server

    Alizadeh, M H

    2015-01-01

    The possibility to enhance chiral light-matter interactions through plasmonic nanostructures provides entirely new opportunities for greatly improving the detection limits of chiroptical spectroscopies down to the single molecule level. The most pronounced of these chiral interactions occur in the ultraviolet (UV) range of the electromagnetic spectrum, which is difficult to access with conventional localized plasmon resonance based sensors. Although Surface Plasmon Polaritons (SPPs) on noble metal films can sustain resonances in the desired spectral range, their transverse magnetic nature has been an obstacle for enhancing chiroptical effects. Here we demonstrate, both analytically and numerically, that SPPs excited by near-field sources can exhibit rich and non-trivial chiral characteristics. In particular, we show that the excitation of SPPs by a chiral source not only results in a locally enhanced optical chirality but also achieves manifold enhancement of net optical chirality. Our finding that SPPs facil...

  16. Packing of Helices: Is Chirality the Highest Crystallographic Symmetry?

    Directory of Open Access Journals (Sweden)

    Romain Gautier

    2016-08-01

    Full Text Available Chiral structures resulting from the packing of helices are common in biological and synthetic materials. Herein, we analyze the noncentrosymmetry (NCS in such systems using crystallographic considerations. A comparison of the chiral structures built from helices shows that the chirality can be expected for specific building units such as 31/32 or 61/65 helices which, in hexagonal arrangement, will more likely lead to a chiral resolution. In these two systems, we show that the highest crystallographic symmetry (i.e., the symmetry which can describe the crystal structure from the smallest assymetric unit is chiral. As an illustration, we present the synthesis of two materials ([Zn(2,2’-bpy3](NbF62 and [Zn(2,2’-bpy3](TaF62 in which the 3n helices pack into a chiral structure.

  17. Identification of Enantioselective Extractants for Chiral Separation of Amines and Amino-Alcohols

    NARCIS (Netherlands)

    Steensma, M.; Kuipers, N.J.M.; de Haan, A.B.; Kwant, Gerard

    2006-01-01

    lack of versatile enantioselective extractants. Therefore, a rational approach is developed to transfer the extensive knowledge of chiral selectors reported in the literature on chiral recognition and other chiral separation techniques to extraction. Based on a similarity in separation mechanisms,

  18. The formation mechanism of chiral carbon nanotubes

    Science.gov (United States)

    Liu, Jing; Liu, Liren; Lu, Junzhe; Zhu, Hengjiang

    2018-02-01

    The nuclei and the formation mechanism of chiral carbon nanotubes, namely, single-, double-, and triple-walled carbon nanotubes are simulated by the first principle density functional theory. The formation mechanism from nuclei to corresponding infinitely long carbon nanotubes occurs spirally and via absorbing carbon atoms layer by layer. Carbon atoms at the open end are metastable state compared with ones in the tube wall or the closed end, which indicate the growth point of chiral carbon nanotubes is located at the open end. Growth of outer layer tubular clusters takes precedence over the inner layer in the process of forming multi-walled nuclear structures. Because of the ratio of carbon atoms at the open end to all carbon atoms decreases, the stability of the tubular clusters increases with their length. The infinitely long carbon nanotubes are obtained by executing periodic boundary conditions depend on corresponding nuclear structures.

  19. Chiral perturbation theory with tensor sources

    Energy Technology Data Exchange (ETDEWEB)

    Cata, Oscar; Cata, Oscar; Mateu, Vicent

    2007-05-21

    We construct the most general chirally-invariant Lagrangian for mesons in the presence of external sources coupled to the tensor current \\bar psi sigma_mu nu psi. In order to have only even terms in the chiral expansion, we consider the new source of O(p2). With this choice, we build the even-parity effective Lagrangian up to the p6-order (NLO). While there are only 4 new terms at the p4-order, at p6-order we find 78 terms for n_f=2 and 113 terms for n_f=3. We provide a detailed discussion on the different mechanisms that ensure that our final set of operators is complete and non-redundant. We also examine the odd-parity sector, to conclude that the first operators appear at the p8-order (NNLO).

  20. New approaches in sensitive chiral CE.

    Science.gov (United States)

    Sánchez-Hernández, Laura; Guijarro-Diez, Miguel; Marina, María Luisa; Crego, Antonio L

    2014-01-01

    CE has shown to have a big potential for chiral separations, with advantages such as high efficiency, high resolution, and low sample and reagents consumption. Nevertheless, when UV detection is employed, CE has some drawbacks, especially the low sensitivity obtained due to the short optical path length. Notwithstanding, sensitivity improvements can be achieved when different approaches are employed, such as sample treatment strategies (off-line or on-line), in-capillary sample preconcentration techniques, and/or alternative detection systems to UV-Vis (such as fluorescence, conductimetry, electrochemiluminiscence, MS, etc.). This article reviews the most recent methodological and instrumental advances reported from June 2011 to May 2013 for enhancing the sensitivity in chiral analysis by CE. The sensitivity achieved for the enantioseparated analytes and the applications carried out using the developed methodologies are also summarized. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Chiral Selectivity as a Bridge to Homochirality

    Science.gov (United States)

    Burton, A. S.; Berger, E. L.

    2017-01-01

    In abiotic reactions, equal mixtures of L- and D- amino acid enantiomers are produced unless conditions that favor one enantiomer over the other are present. Understanding how the transition from racemic, abiotic chemistry to homochiral polymers used in proteins occurred is fundamental to our understanding of the origins of life on Earth and the search for signs of life elsewhere, but this transition is still poorly understood. We have begun investigations into whether enantiopure amino acid pools are a necessary condition, or if the polymerization process itself can impart some added degree of stereoselectivity. More specifically, we are exploring the polymerization behavior of chiral amino acids to determine if they show a preference for homochiral or heterochiral polymerization. We are also determining the effects of different amino acid chiral ratios (L greater than D) to determine at what level of enantiomeric enrichment homochiral peptides become predominant. These data will allow us to evaluate the plausibility of homochiral polymers arising by known abiotic mechanisms.

  2. A primer for Chiral Perturbative Theory

    Energy Technology Data Exchange (ETDEWEB)

    Scherer, Stefan [Mainz Univ. (Germany). Inst. fuer Kernphysik; Schindler, Matthias R. [South Carolina Univ., Columbia, SC (United States). Dept. of Physics; George Washington Univ., Washington, DC (United States). Dept. of Physics

    2012-07-01

    Chiral Perturbation Theory, as effective field theory, is a commonly accepted and well established working tool, approximating quantum chromodynamics at energies well below typical hadron masses. This volume, based on a number of lectures and supplemented with additional material, provides a pedagogical introduction for graduate students and newcomers entering the field from related areas of nuclear and particle physics. Starting with the the Lagrangian of the strong interactions and general symmetry principles, the basic concepts of Chiral Perturbation Theory in the mesonic and baryonic sectors are developed. The application of these concepts is then illustrated with a number of examples. A large number of exercises (81, with complete solutions) are included to familiarize the reader with helpful calculational techniques. (orig.)

  3. Chiral Response of Twisted Bilayer Graphene

    Science.gov (United States)

    Stauber, T.; Low, T.; Gómez-Santos, G.

    2018-01-01

    We present an effective (minimal) theory for chiral two-dimensional materials. These materials possess an electromagnetic coupling without exhibiting a topological gap. As an example, we study the response of doped twisted bilayers, unveiling unusual phenomena in the zero frequency limit. An in-plane magnetic field induces a huge paramagnetic response at the neutrality point and, upon doping, also gives rise to a substantial longitudinal Hall response. The system also accommodates nontrivial longitudinal plasmonic modes that are associated with a longitudinal magnetic moment, thus endowing them with a chiral character. Finally, we note that the optical activity can be considerably enhanced upon doping and our general approach would enable systematic exploration of 2D material heterostructures with optical activity.

  4. Sensing and actuation of smart chiral honeycombs

    Science.gov (United States)

    Abramovitch, H.; Burgard, M.; Edery-Azulay, Lucy; Evans, K. E.; Hoffmeister, M.; Miller, W.; Scarpa, F.; Smith, C. W.; Tee, K. F.; Schönecker, A.; Seffner, L.

    2008-03-01

    A chiral honeycomb configuration is developed with embedded piezosensors and actuators for smart sandwich panel applications. The chiral honeycomb concept is made of repeating units of cylinders and plates (ligaments), featuring an in-plane negative Poisson's ratio. Rapid Prototyping vacuum-cast and FDM (Fusion Deposition Moulding) techniques are developed to embed micro fibres composites to be used for potential structural health monitoring (SHM) applications, and microwave absorption screens for electromagnetic compatibility. Finite Element models are also developed to prototype and simulate the response, sensing and actuation capability of the honeycombs for design purposes. Dynamic tests using scanning laser vibrometers and acoustic wave propagation are carried out to assess the feasibility of the concept.

  5. A primer for chiral perturbation theory

    CERN Document Server

    Scherer, Stefan

    2012-01-01

    Chiral Perturbation Theory, as effective field theory, is a commonly accepted and well established working tool, approximating quantum chromodynamics at energies well below typical hadron masses. This volume, based on a number of lectures and supplemented with additional material, provides a pedagogical introduction for graduate students and newcomers entering the field from related areas of nuclear and particle physics. Starting with the the Lagrangian of the strong interactions and general symmetry principles, the basic concepts of Chiral Perturbation Theory in the mesonic and baryonic sectors are developed. The application of these concepts is then illustrated with a number of examples. A large number of exercises (81, with complete solutions) are included to familiarize the reader with helpful calculational techniques.

  6. Stereoselective synthesis of perillaldehyde-based chiral β-amino acid derivatives through conjugate addition of lithium amides

    Directory of Open Access Journals (Sweden)

    Zsolt Szakonyi

    2014-11-01

    Full Text Available The Michael addition of dibenzylamine to (+-tert-butyl perillate (3 and to (+-tert-butyl phellandrate (6, derived from (S-(−-perillaldehyde (1, resulted in diastereomeric β-amino esters 7A–D in a moderately stereospecific reaction in a ratio of 76:17:6:1. After separation of the diastereoisomers, the major product, cis isomer 7A, was quantitatively isomerized to the minor component, trans-amino ester 7D. All four isomers were transformed to the corresponding β-amino acids 10A–D, which are promising building blocks for the synthesis of β-peptides and 1,3-heterocycles in three steps. The steric effects of the isopropyl group at position 4 and of the α-methyl substituent of (R-N-benzyl-N-α-methylbenzylamine on the reactivity were also studied and, upon application of a chiral amine, excellent stereoselectivity of the conjugate addition was observed. Amino ester 11 was obtained as a single product and transformed to the corresponding amino acids 10A and 10D in good yields on the gram scale.

  7. Note on the Lattice Fermion Chiral Symmetry Group

    OpenAIRE

    Mandula, Jeffrey E.

    2007-01-01

    The group structure of the variant chiral symmetry discovered by Luscher in the Ginsparg-Wilson description of lattice chiral fermions is analyzed. It is shown that the group contains an infinite number of linearly independent symmetry generators, and the Lie algebra is given explicitly. CP is an automorphism of the chiral group, and the CP transformation properties of the symmetry generators is found. Features of the currents associated with these symmetries are discussed, including the fact...

  8. Chiral perturbation theory for nucleon generalized parton distributions

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Manashov, A. [Regensburg Univ. (Germany). Inst. fuer Physik 1 - Theoretische Physik]|[Sankt-Petersburg State Univ. (Russian Federation). Dept. of Theoretical Physics; Schaefer, A. [Regensburg Univ. (Germany). Inst. fuer Physik 1 - Theoretische Physik

    2006-08-15

    We analyze the moments of the isosinglet generalized parton distributions H, E, H, E of the nucleon in one-loop order of heavy-baryon chiral perturbation theory. We discuss in detail the construction of the operators in the effective theory that are required to obtain all corrections to a given order in the chiral power counting. The results will serve to improve the extrapolation of lattice results to the chiral limit. (orig.)

  9. Chiral Rayleigh particles discrimination in dynamic dual optical traps

    Science.gov (United States)

    Carretero, Luis; Acebal, Pablo; Blaya, Salvador

    2017-11-01

    A chiral optical conveyor belt for enantiomeric separation of nanoparticles is numerically demonstrated by using different types of counter propagating elliptical Laguerre Gaussian beams with different beam waist and topological charge. The analysis of chiral resolution has been made for particles immersed in water demonstrating that in the analyzed conditions one type of enantiomer is trapped in a deep potential and the others are transported by the chiral conveyor toward another trap located in a different geometrical region.

  10. Chiral symmetry on the lattice with Wilson fermions

    Energy Technology Data Exchange (ETDEWEB)

    Bochicchio, M.; Maiani, L.; Martinelli, G.; Rossi, G.; Testa, M.

    1985-12-16

    The chiral properties of the continuum limit of lattice QCD with Wilson fermions are studied. We show that a partially conserved axial current can be defined, satisfying the usual current algebra requirements. A proper definition of the chiral symmetry order parameter, <0 vertical stroke anti psi psi vertical stroke 0>, is given, and the chiral properties of composite operators are investigated. The implications of our analysis to the lattice determination of non-leptonic weak amplitudes are also discussed. (orig.).

  11. Chiral quaternary phosphonium salts: a new class of organocatalysts.

    Science.gov (United States)

    Enders, Dieter; Nguyen, Thanh Vinh

    2012-07-28

    Phase-transfer catalysis has widely been used as a prime synthetic tool for both laboratory and industrial processes. During the last twenty years, asymmetric phase-transfer catalysis using chiral organocatalysts has attracted widespread interest. However, the scope of chiral phase-transfer catalysis has been limited mostly to the quaternary ammonium salts. As an emerging area, the recent developments in the application of quaternary phosphonium salts as chiral phase-transfer catalysts are discussed in this article.

  12. Emerging functional chiral microporous materials: synthetic strategies and enantioselective separations

    OpenAIRE

    Xue, Ming; Li, Bin; Qiu, Shilun; Chen, Banglin

    2016-01-01

    In recent years, chiral microporous materials with open pores have attracted much attention because of their potential applications in enantioselective separation and catalysis. This review summarizes the recent advances on chiral microporous materials, such as metal-organic frameworks (MOFs), hydrogen-bonded organic frameworks (HOFs) and covalent organic frameworks (COFs). We will introduce the synthetic strategies in detail and highlight the current status of chiral microporous materials on...

  13. What flows in the chirally anomalous transport?

    Energy Technology Data Exchange (ETDEWEB)

    Fukushima, Kenji

    2016-12-15

    A combination of the magnetic field and the quantum anomaly leads to transport phenomena of chiral fermions. On the microscopic level, however, what really flows is a non-trivial question. I propose an answer to this question; the particle production affected by the magnetic field and the quantum anomaly has an anisotropic distribution in momentum space, which should be realized in the heavy-ion collision by a fast process occurring on top of color flux tubes in the glasma.

  14. Chiral Biomarkers and Microfossils in Carbonaceous Meteorites

    Science.gov (United States)

    Hoover, Richard B.

    2010-01-01

    Homochirality of the biomolecules (D-sugars of DNA and RNA and L-amino acids of proteins) is a fundamental property of all life on Earth. Abiotic mechanisms yield racemic mixtures (D/L=1) of chiral molecules and after the death of an organism, the enantiopure chiral biomolecules slowly racemize. Several independent investigators have now established that the amino acids present in CI1 and CM2 carbonaceous meteorites have a moderate to strong excess of the L-enantiomer. Stable isotope data have established that these amino acids are both indigenous and extraterrestrial. Carbonaceous meteorites also contain many other strong chemical biomarkers including purines and pyrimidines (nitrogen heterocycles of nucleic acids); pristine and phytane (components of the chlorophyll pigment) and morphological biomarkers (microfossils of filamentous cyanobacteria). Energy dispersive X-ray Spectroscopy (EDS) analysis reveals that nitrogen is below the detectability level in most of the meteorite filaments as well as in Cambrian Trilobites and filaments of 2.7 Gya Archaean cyanobacteria from Karelia. The deficiency of nitrogen in the filaments and the total absence of sugars, of twelve of the life-critical protein amino acids, and two of the nucleobases of DNA and RNA provide clear and convincing evidence that these filaments are not modern biological contaminants. This paper reviews the chiral, chemical biomarkers morphological biomarkers and microfossils in carbonaceous meteorites. This paper reviews chiral and morphological biomarkers and discusses the missing nitrogen, sugars, protein amino acids, and nucleobases as ?bio-discriminators? that exclude modern biological contaminants as a possible explanation for the permineralized cyanobacterial filaments found in the meteorites.

  15. Chiral Molecule in the Standard Model

    OpenAIRE

    Fukuyama, Takeshi

    2014-01-01

    This review is based on the talk in the conference of "Spectroscopic Studies on Molecular Chirality" held on Dec 20-21 2013. The objects of the present paper are to (1) derive the energy difference between Laevorotatory, or left-handed, (L-) and Dextrotatory, or right-handed, (D-) molecules and to (2) discuss how this tiny energy difference leads us to the observed enantiomer excess. Relations with other parity violating phenomena in molecules, electric dipole moment and natural optical activ...

  16. Hadron Structure in Chiral Perturbation Theory

    Energy Technology Data Exchange (ETDEWEB)

    Aleksejevs, A. [Grenfell campus of Memorial University, Newfoundland (Canada); Barkanova, S. [Acadia University, Nova Scotia (Canada)

    2013-12-15

    We present our predictions for meson form factors for the SU(3) octet and investigate their impact on the pion electroproduction cross sections. The electric and magnetic polarizabilities of the SU(3) octet of mesons and baryons are analyzed in detail. These extensive calculations are made possible by the recent implementation of semi-automatized calculations in fully-relativistic chiral perturbation theory, which allows evaluation of polarizabilities from Compton scattering up to next-to-the-leading order.

  17. Chiral biomarkers and microfossils in carbonaceous meteorites

    Science.gov (United States)

    Hoover, Richard B.

    2010-09-01

    Homochirality of the biomolecules (D-sugars of DNA and RNA and L-amino acids of proteins) is a fundamental property of all life on Earth. Abiotic mechanisms yield racemic mixtures (D/L=1) of chiral molecules and after the death of an organism, the enantiopure chiral biomolecules slowly racemize. Several independent investigators have now established that the amino acids present in CI1 and CM2 carbonaceous meteorites have a moderate to strong excess of the L-enantiomer. Stable isotope data have established that these amino acids are both indigenous and extraterrestrial. Carbonaceous meteorites also contain many other strong chemical biomarkers including purines and pyrimidines (nitrogen heterocycles of nucleic acids); pristine and phytane (components of the chlorophyll pigment) and morphological biomarkers (microfossils of filamentous cyanobacteria). Energy dispersive X-ray Spectroscopy (EDS) analysis reveals that nitrogen is below the detectability level in most of the meteorite filaments as well as in Cambrian Trilobites and filaments of 2.7 Gya Archaean cyanobacteria from Karelia. The deficiency of nitrogen in the filaments and the total absence of sugars, of twelve of the life-critical protein amino acids, and two of the nucleobases of DNA and RNA provide clear and convincing evidence that these filaments are not modern biological contaminants. This paper reviews the chiral, chemical biomarkers morphological biomarkers and microfossils in carbonaceous meteorites. This paper reviews chiral and morphological biomarkers and discusses the missing nitrogen, sugars, protein amino acids, and nucleobases as "bio-discriminators" that exclude modern biological contaminants as a possible explanation for the permineralized cyanobacterial filaments found in the meteorites.

  18. Chiral discrimination in biomimetic systems: Phenylalanine

    Indian Academy of Sciences (India)

    WINTEC

    cine derivatives were synthesized and stereoselectivity was measured using IC50 potency assay.6 Naturally occurring L-puromycine inhibits globin mRNA trans- lation with an IC50 of 1⋅8 μM and D-puromycine inhibit translation giving an IC50 of 280 μM. The difference is 150-fold and is a signature of strong chiral dis-.

  19. Circular Intensity Differential Scattering of chiral molecules

    Energy Technology Data Exchange (ETDEWEB)

    Bustamante, C.J.

    1980-12-01

    In this thesis a theory of the Circular Intensity Differential Scattering (CIDS) of chiral molecules as modelled by a helix oriented with respect to the direction of incidence of light is presented. It is shown that a necessary condition for the existence of CIDS is the presence of an asymmetric polarizability in the scatterer. The polarizability of the scatterer is assumed generally complex, so that both refractive and absorptive phenomena are taken into account.

  20. Enantiomeric separation of iridium (III) complexes using HPLC chiral stationary phases based on amylose derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hee Eun; Seo, Na Hyeon; Hyun, Myung Ho [Dept. of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan (Korea, Republic of)

    2016-12-15

    Cyclometalated iridium (III) complexes formed with three identical cyclometalating (C-N) ligands (homoleptic) or formed with two cyclometalating (C-N) ligands and one ancillary (LX) ligand (heteroleptic) have been known as highly phosphorescent materials and, thus, they have been utilized as efficient phosphorescent dopants in organic light emitting diodes (OLEDs) 1–3 or as effective phosphorescent chemosensors. 4–7 Cylometalated iridium (III) complexes are chiral compounds consisting of lambda (Λ, left-handed) and delta (Δ, right-handed) isomers. Racemic cyclometa- lated iridium (III) complexes emit light with no net polarization, but optically active cyclometalated iridium (III) complexes emit circularly polarized light. 8,9 Circularly polarized light can be used in various fields including highly efficient three dimensional electronic devices, photo nic devices for optical data storage, biological assays, and others. 8,9 In order to obtain optically active cylometalated iridium (III) complexes and to determine the enantiomeric composition of optically active cylometalated iridium (III) complexes, liquid chromatogr aphic enantiomer separation method on chiral stationary phases (CSPs) has been used. For example, Okamoto and coworkers first reported the high performance liquid chromatographic (HPLC) direct enantiomeric separation of two homoleptic cylometalated iridium (III) complexes on immobilized amylose tris(3,5- dimethylphenylcarbamate) (Chiralpak IA), coated cellulose tris(3,5-dimethylphenylcarbamate) (Chiralc el OD), and coated cellulose tris(4-methylbenzoate) (Chiralce l OJ). 10 Supercritical fluid chromatography (SFC) was also used by Bernhard and coworkers for the enantiomeric separation of cylometalated iridium (III) complexes on coated amylose tris(3,5-dimethylphenylcarbamate) (Chiralpak AD-H). 8 However, the general use of the HPLC method for the direct enantiomeric separation of homoleptic.

  1. Optical Activity and Optical Anisotropy in Photomechanical Crystals of Chiral Salicylidenephenylethylamines.

    Science.gov (United States)

    Takanabe, Akifumi; Tanaka, Masahito; Johmoto, Kohei; Uekusa, Hidehiro; Mori, Tadashi; Koshima, Hideko; Asahi, Toru

    2016-11-16

    Introducing chirality into photomechanical crystals is beneficial for the diversification of mechanical motion. Measurement of the chiroptical and optical anisotropic properties of chiral crystals is indispensable for evaluating photomechanical crystals. The platelike crystals of S- and R-enantiomers of photochromic N-3,5-di-tert-butylsalicylidene-1-phenylethylamine in enol form (enol-(S)-1 and enol-(R)-1) caused bending motion with twisting upon ultraviolet (UV) light irradiation, due to shrinkage along the length and width directions of the irradiated surface, based on the optimized crystal structure of the photoisomerized trans-keto-(S)-1. By employing the generalized high-accuracy universal polarimeter (G-HAUP), optical anisotropic (linear birefringence, LB; linear dichroism, LD) as well as chiroptical (circular birefringence, CB; circular dichroism, CD) spectra of both the enantiomeric crystals on the (001) face were simultaneously measured before and under continuous UV irradiation. The LD peak was observed at 330 nm in the negative sign, derived from the π-π* transition of the intramolecularly hydrogen-bonded salicylidenimino moiety. The CD spectra of the S and R crystals revealed the negative and positive Cotton effect at 330 nm, respectively, and new peaks appeared at 460 nm under UV light irradiation due to photoisomerization to the S and R trans-keto isomers at around 10% conversion. The CB and CD spectra evaluated by the HAUP measurement were opposite to those measured in the hexane solution, as well as those simulated by quantum chemical calculation. The dissymmetry parameter, g, of the enol-(S)-1 crystal along the c axis (0.013) was approximately 10 times larger than the g values in the solution (0.0010) and by calculation (0.0016).

  2. Analysis of shape isomer yields of Pu in the framework of dynamical ...

    Indian Academy of Sciences (India)

    of induced fission [1] to analyse experimental fission probabilities of some Pu isotopes and shape isomer yields ... It should be stressed that so far experimental data on shape isomer yields for 237Pu have only been analysed on ... (2) population of the second potential well and cooling via particle or γ emission (this event is ...

  3. The behaviour of EDDHA isomers in soils as influenced by soil properties.

    NARCIS (Netherlands)

    Schenkeveld, W.D.C.; Reichwein, A.M.; Temminghoff, E.J.M.; Riemsdijk, van W.H.

    2007-01-01

    FeEDDHA products are applied to correct iron chlorosis in plants and consist of a mixture of EDDHA isomers chelated to iron. In this study such mixtures have been divided into four (groups of) isomers: racemic o,o-EDDHA, meso o,o-EDDHA, o,p-EDDHA and rest-EDDHA. The physical and chemical properties

  4. Tris(β-diketonato) Ru(III) complexes as chiral dopants for nematic liquid crystals: the effect of the molecular structure on the helical twisting power.

    Science.gov (United States)

    Yoshida, Jun; Watanabe, Go; Kakizawa, Kaori; Kawabata, Yasuhiro; Yuge, Hidetaka

    2013-10-07

    Doping nematic liquid crystals with optically active compounds transforms them into chiral nematic phases with helical structures. In this phenomenon, the chirality of the dopant molecules is transferred or amplified to the bulk of the liquid crystals. Δ-[Ru(acac)3] (acac = acetylacetonato) is known to work as one of the dopants with a strong helical twisting power (HTP). In this study, we have systematically modified [Ru(acac)3] to clarify the correlation between the molecular structure and HTP; we have designed and synthesized five new Ru(III) complexes, [Ru(acac)2(acacC8)] (RuC8-1, acac = acetylacetonate, acacC8 = 3-(4'-octyloxy-phenylalkynyl)-pentane-2,4-dionato), [Ru(acac)(acacC8)2] (RuC8-2), [Ru(acacC8)3] (RuC8-3), [Ru(acacC0)3] (RuC0-3, acacC0 = 3-(phenylalkynyl)-pentane-2,4-dionato), and [Ru(acacC24)3] (RuC24-3, acacC24 = 3-(3',4',5'-tri(octyloxy)-phenylalkynyl)-pentane-2,4-dionato). All the complexes, except for RuC0-3, could be separated into Δ, Λ isomers by HPLC on a chiral column and were examined as chiral dopants for a nematic liquid crystal, N-(4-methoxybenzilidene)-4-butylaniline (MBBA). The Δ isomers of RuC8-1, RuC8-2, RuC8-3, and RuC24-3 induced a right-handed (P) helix and the magnitudes of the HTPs (/μm(-1)) were determined as follows: RuC8-1 (+60) RuC8-3 (+78) > RuC24-3 (+41). The HTPs of the ruthenium dopants were not simply proportional to their size. The highest HTP observed in biaxial RuC8-2 was attributed to the balance of the molecular helicity and high ordering in MBBA based on the surface chirality model.

  5. Chiral Receiving Antenna With Low Backscattering Levels

    CERN Document Server

    Karilainen, Antti O

    2011-01-01

    Receiving antennas absorb power from incident waves, but they also re-radiate some power into surrounding space. If a receiving antenna is to be used as a sensor which should not disturb the object under study, it should scatter as little power as possible in the receiving direction. We propose to use a chiral element composed of two orthogonal chiral particles as a low-scattering sensor.The element can transmit and receive circular polarization in all directions with the Huygens' pattern. We derive the vector effective length for the antenna using the small dipole approximation for the chiral particles. We observe that the element does not backscatter, regardless of the polarization, when the incidence direction is normal to the plane of the particles. Scattered fields, scattered axial ratio, and the scattering cross section are presented. We show that the zero-backscattering property holds also for the antenna element when it is capable to receive all the available power with conjugate loading. The approxim...

  6. Chiral symmetry breaking in unstirred crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Szurgot, M. [Center of Mathematics and Physics, Technical University of Lodz (Poland)

    2012-01-15

    Statistics of nucleation of chiral forms of sodium bromate from unstirred aqueous solutions was studied. It was established that bimodal, trimodal and unimodal distributions of enantiomers are obtained in unstirred crystallization. It was also found out that probabilities of the creation of L or D crystals and racemates R, as well as the presence of D, L, and R peaks in distributions depend on crystallizer size, supersaturation and temperature. Nucleation at low supersaturations in small, closed crystallizers leads to the formation of pure enantiomers, and to bimodal distributions with D and L peaks at any temperature. At high supersaturations in large, open crystallizers the formation of racemates and unimodal distributions with racemate R peaks results. In open crystallizers at the lowest temperatures and at the highest temperatures used in crystallization from aqueous solution racemates of sodium bromate are preferentially formed, but in a wide range of intermediate-temperatures apart from racemates, pure enantiomers are efficiently formed which leads to trimodal distributions. The spontaneous formation of pure enantiomers in crystallization from unstirred, unseeded solutions is caused by the chiral symmetry breaking phenomenon, the same as that discovered in stirred crystallization. The conservation of chiral symmetry is, in unstirred crystallization, one of the two possibilities, and the other one is the breakage of symmetry. Both of them occur in nature. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Chirality-induced magnon transport in AA-stacked bilayer honeycomb chiral magnets

    Science.gov (United States)

    Owerre, S. A.

    2016-11-01

    In this Letter, we study the magnetic transport in AA-stacked bilayer honeycomb chiral magnets coupled either ferromagnetically or antiferromagnetically. For both couplings, we observe chirality-induced gaps, chiral protected edge states, magnon Hall and magnon spin Nernst effects of magnetic spin excitations. For ferromagnetically coupled layers, thermal Hall and spin Nernst conductivities do not change sign as function of magnetic field or temperature similar to single-layer honeycomb ferromagnetic insulator. In contrast, for antiferromagnetically coupled layers, we observe a sign change in the thermal Hall and spin Nernst conductivities as the magnetic field is reversed. We discuss possible experimental accessible honeycomb bilayer quantum materials in which these effects can be observed.

  8. Enantiomeric separations of chiral pharmaceuticals using chirally modified tetrahexahedral Au nanoparticles

    Science.gov (United States)

    Shukla, N.; Yang, D.; Gellman, A. J.

    2016-06-01

    Tetrahexahedral (THH, 24-sided) Au nanoparticles modified with D- or L-cysteine (Cys) have been used as enantioselective separators of the chiral pharmaceutical propranolol (PLL) in solution phase. Polarimetry has been used to measure the rotation of linearly polarized light by solutions containing mixtures of PLL and Cys/THH-Au NPs with varying enantiomeric excesses of each. Polarimetry yields clear evidence of enantiospecific adsorption of PLL onto the Cys/THH-Au NPs. This extends prior work using propylene oxide as a test chiral probe, by using the crystalline THH Au NPs with well-defined facets to separate a real pharmaceutical. This work suggests that chiral nanoparticles, coupled with a density separation method such as centrifugation, could be used for enantiomeric purification of real pharmaceuticals. A simple robust model developed earlier has also been used to extract the enantiospecific equilibrium constants for R- and S-PLL adsorption onto the D- and L-Cys/THH-Au NPs.

  9. Pharmacokinetics of the active antifungal enantiomer, SCH 42427 (RR), and evaluation of its chiral inversion in animals following its oral administration and the oral administration of its racemate genaconazole (RR/SS).

    Science.gov (United States)

    Kim, Hong; Radwanski, Elaine; Lovey, Raymond; Lin, Chin-Chung; Nomeir, Amin A

    2002-05-15

    Genaconazole (SCH 39304) is a potent triazole antifungal agent that is active both orally and topically. Genaconazole is a racemic mixture which contains 50% of the RR (SCH 42427) and 50% of the SS (SCH 42426) enantiomers. The RR isomer accounts for most of the antifungal activity of genaconazole. Serum concentrations of the RR and SS enantiomers were analyzed by a chiral HPLC method which involved extraction of serum with organic solvent followed by separation on a Cyclobond I column and quantification by UV absorbance at 205 nm. The bioavailability and pharmacokinetic profiles of the two enantiomers after oral administration of the racemate (genaconazole) were very similar in cynomolgus monkeys. In rats following dosing with genaconazole, the RR enantiomer had a lower C(max) and a longer t(1/2) than the SS enantiomer, while the AUC(I) values of the two enantiomers were similar. Based on chiral HPLC analysis, there was no evidence for the inversion of the RR to the SR isomer, or of the SS to the SR isomer, indicating that there was no chiral inversion of the RR or SS enantiomers in either species. Genaconazole at 20 mg/kg and the RR (SCH 42427) enantiomer at 10 mg/kg had very similar serum concentration-time profiles and C(max), AUC(I), and t(1/2) values for the RR enantiomer in both rats and monkeys, indicating that the two treatments were equivalent with respect to the bioavailability of the RR enantiomer. Copyright 2002 Wiley-Liss, Inc.

  10. The Three Dimensional Dual of 4D Chirality

    CERN Document Server

    Porrati, M

    2009-01-01

    Chiral gauge theories can be defined in four-dimensional Anti de Sitter space, but AdS boundary conditions explicitly break the chiral symmetry in a specific, well defined manner, which in turns results in an anomalous Ward identity. When the 4D theory admits a dual description in terms of a 3D CFT, the 3D dual of the broken chiral symmetry is a certain double-trace deformation of the CFT, which produces the same anomalous chiral Ward identities that obtains in the 4D bulk theory.

  11. Partial restoration of chiral symmetry in the color flux tube

    Science.gov (United States)

    Iritani, Takumi; Cossu, Guido; Hashimoto, Shoji

    2015-05-01

    Using the quark eigenmodes computed on the lattice with the overlap-Dirac operator, we investigate the spatial distribution of the chiral condensate around static color sources corresponding to quark-antiquark and three-quark systems. A flux structure of chromo fields appears in the presence of such color charges. The magnitude of the chiral condensate is reduced inside the color flux, which implies partial restoration of chiral symmetry inside hadrons. Taking a static baryon source in a periodic box as a toy model of nuclear matter, we estimate the magnitude of the chiral symmetry restoration as a function of baryon matter density.

  12. Chiral nucleon-nucleon forces in nuclear structure calculations

    Directory of Open Access Journals (Sweden)

    Coraggio L.

    2016-01-01

    Full Text Available Realistic nuclear potentials, derived within chiral perturbation theory, are a major breakthrough in modern nuclear structure theory, since they provide a direct link between nuclear physics and its underlying theory, namely the QCD. As a matter of fact, chiral potentials are tailored on the low-energy regime of nuclear structure physics, and chiral perturbation theory provides on the same footing two-nucleon forces as well as many-body ones. This feature fits well with modern advances in ab-initio methods and realistic shell-model. Here, we will review recent nuclear structure calculations, based on realistic chiral potentials, for both finite nuclei and infinite nuclear matter.

  13. Heavy–light mesons in chiral AdS/QCD

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yizhuang, E-mail: yizhuang.liu@stonybrook.edu; Zahed, Ismail, E-mail: ismail.zahed@stonybrook.edu

    2017-06-10

    We discuss a minimal holographic model for the description of heavy–light and light mesons with chiral symmetry, defined in a slab of AdS space. The model consists of a pair of chiral Yang–Mills and tachyon fields with specific boundary conditions that break spontaneously chiral symmetry in the infrared. The heavy–light spectrum and decay constants are evaluated explicitly. In the heavy mass limit the model exhibits both heavy-quark and chiral symmetry and allows for the explicit derivation of the one-pion axial couplings to the heavy–light mesons.

  14. Chirality-dependent cellular uptake of chiral nanocarriers and intracellular delivery of different amounts of guest molecules

    Science.gov (United States)

    Kehr, Nermin Seda; Jose, Joachim

    2017-12-01

    We demonstrate the organic molecules loaded and chiral polymers coated periodic mesoporous organosilica (PMO) to generate chiral nanocarriers that we used to study chirality-dependent cellular uptake in serum and serum-free media and the subsequent delivery of different amounts of organic molecules into cells. Our results show that the amount of internalized PMO and thus the transported amount of organic molecules by nanocarrier PMO into cells was chirality dependent and controlled by hard/soft protein corona formation on the PMO surfaces. Therefore, this study demonstrate that chiral porous nanocarriers could potentially be used as advanced drug delivery systems which are able to use the specific chiral surface-protein interactions to influence/control the amount of (bio)active molecules delivered to cells in drug delivery and/or imaging applications.

  15. Energetics of cyclohexane isomers: a density-functional study

    CERN Document Server

    Lee, C Y

    1999-01-01

    The binding energies and the geometric structures of conformational isomers of cyclohexane (C sub 6 H sub 1 sub 2) are determined from the density-functional theory combined with ultrasoft pseudopotentials and gradient-corrected nonlocal exchange-correlation functionals. The ground-state chair conformation is found to have a binding energy of 99.457 eV, and the metastable twist-boat conformation has 99.161 eV. The chair conformation converts to another conformation via a half-chair conformation with an energy barrier of 0.507 eV whereas the twist-boat conformation converts to another twist-boat conformation via a boat conformation with a much smaller energy barrier of 0.015 eV.

  16. Lutein and Zeaxanthin Isomers in Eye Health and Disease.

    Science.gov (United States)

    Mares, Julie

    2016-07-17

    Current evidence suggests lutein and its isomers play important roles in ocular development in utero and throughout the life span, in vision performance in young and later adulthood, and in lowering risk for the development of common age-related eye diseases in older age. These xanthophyll (oxygen-containing) carotenoids are found in a wide variety of vegetables and fruits, and they are present in especially high concentrations in leafy green vegetables. Additionally, egg yolks and human milk appear to be bioavailable sources. The prevalence of lutein, zeaxanthin, and meso-zeaxanthin in supplements is increasing. Setting optimal and safe ranges of intake requires additional research, particularly in pregnant and lactating women. Accumulating evidence about variable interindividual response to dietary intake of these carotenoids, based on genetic or metabolic influences, suggests that there may be subgroups that benefit from higher levels of intake and/or alternate strategies to improve lutein and zeaxanthin status.

  17. Electronic Single Molecule Identification of Carbohydrate Isomers by Recognition Tunneling

    CERN Document Server

    Im, JongOne; Liu, Hao; Zhao, Yanan; Sen, Suman; Biswas, Sudipta; Ashcroft, Brian; Borges, Chad; Wang, Xu; Lindsay, Stuart; Zhang, Peiming

    2016-01-01

    Glycans play a central role as mediators in most biological processes, but their structures are complicated by isomerism. Epimers and anomers, regioisomers, and branched sequences contribute to a structural variability that dwarfs those of nucleic acids and proteins, challenging even the most sophisticated analytical tools, such as NMR and mass spectrometry. Here, we introduce an electron tunneling technique that is label-free and can identify carbohydrates at the single-molecule level, offering significant benefits over existing technology. It is capable of analyzing sub-picomole quantities of sample, counting the number of individual molecules in each subset in a population of coexisting isomers, and is quantitative over more than four orders of magnitude of concentration. It resolves epimers not well separated by ion-mobility and can be implemented on a silicon chip. It also provides a readout mechanism for direct single-molecule sequencing of linear oligosaccharides.

  18. An inconvenient influence of iridium(III) isomer on OLED efficiency.

    Science.gov (United States)

    Baranoff, Etienne; Bolink, Henk J; De Angelis, Filippo; Fantacci, Simona; Di Censo, Davide; Djellab, Karim; Grätzel, Michael; Nazeeruddin, Md Khaja

    2010-10-14

    The recently reported heteroleptic cyclometallated iridium(III) complex [Ir(2-phenylpyridine)(2)(2-carboxy-4-dimethylaminopyridine)] N984 and its isomer N984b have been studied more in detail. While photo- and electrochemical properties are very similar, DFT/TDDFT calculations show that the two isomers have different HOMO orbital characteristics. As a consequence, solution processed OLEDs made using a mixture of N984 and isomer N984b similar to vacuum processed devices show that the isomer has a dramatic detrimental effect on the performances of the device. In addition, commonly used thermogravimetric analysis is not suitable for showing the isomerization process. The isomer could impact performances of vacuum processed OLEDs using heteroleptic cyclometallated iridium(III) complexes as dopant.

  19. Comparative Autoignition Trends in Butanol Isomers at Elevated Pressure

    KAUST Repository

    Weber, Bryan W.

    2013-03-21

    Autoignition experiments of stoichiometric mixtures of s-, t-, and i-butanol in air have been performed using a heated rapid compression machine (RCM). At compressed pressures of 15 and 30 bar and for compressed temperatures in the range 715-910 K, no evidence of a negative temperature coefficient region in terms of ignition delay response is found. The present experimental results are also compared with previously reported RCM data of n-butanol in air. The order of reactivity of the butanols is n-butanol > s-butanol ≈ i-butanol > t-butanol at the lower pressure but changes to n-butanol > t-butanol > s-butanol > i-butanol at higher pressure. In addition, t-butanol shows preignition heat release behavior, which is especially evident at higher pressures. To help identify the controlling chemistry leading to this preignition heat release, off-stoichiometric experiments are further performed at 30 bar compressed pressure, for t-butanol at φ = 0.5 and φ = 2.0 in air. For these experiments, higher fuel loading (i.e., φ = 2.0) causes greater preignition heat release (as indicated by greater pressure rise) than the stoichiometric or φ = 0.5 cases. Comparison of the experimental ignition delays with the simulated results using two literature kinetic mechanisms shows generally good agreement, and one mechanism is further used to explore and compare the fuel decomposition pathways of butanol isomers. Using this mechanism, the importance of peroxy chemistry in the autoignition of the butanol isomers is highlighted and discussed. © 2013 American Chemical Society.

  20. Table of superdeformed nuclear bands and fission isomers

    Energy Technology Data Exchange (ETDEWEB)

    Firestone, R.B. [Lawrence Berkeley Lab., CA (United States); Singh, B. [McMaster Univ., Hamilton, ON (Canada)

    1994-06-01

    A minimum in the second potential well of deformed nuclei was predicted and the associated shell gaps are illustrated in the harmonic oscillator potential shell energy surface calculations shown in this report. A strong superdeformed minimum in {sup 152}Dy was predicted for {beta}{sub 2}-0.65. Subsequently, a discrete set of {gamma}-ray transitions in {sup 152}DY was observed and, assigned to the predicted superdeformed band. Extensive research at several laboratories has since focused on searching for other mass regions of large deformation. A new generation of {gamma}-ray detector arrays is already producing a wealth of information about the mechanisms for feeding and deexciting superdeformed bands. These bands have been found in three distinct regions near A=l30, 150, and 190. This research extends upon previous work in the actinide region near A=240 where fission isomers were identified and also associated with the second potential well. Quadrupole moment measurements for selected cases in each mass region are consistent with assigning the bands to excitations in the second local minimum. As part of our committment to maintain nuclear structure data as current as possible in the Evaluated Nuclear Structure Reference File (ENSDF) and the Table of Isotopes, we have updated the information on superdeformed nuclear bands. As of April 1994, we have complied data from 86 superdeformed bands and 46 fission isomers identified in 73 nuclides for this report. For each nuclide there is a complete level table listing both normal and superdeformed band assignments; level energy, spin, parity, half-life, magneto moments, decay branchings; and the energies, final levels, relative intensities, multipolarities, and mixing ratios for transitions deexciting each level. Mass excess, decay energies, and proton and neutron separation energies are also provided from the evaluation of Audi and Wapstra.