218 research outputs found

    Raman fingerprints on the Bloch sphere of a spinor Bose-Einstein condensate

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    We explore the geometric interpretation of a diabatic, two-photon Raman process as a rotation on the Bloch sphere for a pseudo-spin-1/2 system. The spin state of a spin-1/2 quantum system can be described by a point on the surface of the Bloch sphere, and its evolution during a Raman pulse is a trajectory on the sphere determined by properties of the optical beams: the pulse area, the relative intensities and phases, and the relative frequencies. We experimentally demonstrate key features of this model with a 87^{87}Rb spinor Bose-Einstein condensate, which allows us to examine spatially dependent signatures of the Raman beams. The two-photon detuning allows us to precisely control the spin density and imprinted relative phase profiles, as we show with a coreless vortex. With this comprehensive understanding and intuitive geometric interpretation, we use the Raman process to create and tailor as well as study and characterize exotic topological spin textures in spinor BECs.Comment: 13 pages, 13 figures, submitted to the Journal of Modern Optics "20 Years of Bose-Einstein condensates" Special Issu

    EVALUATION OF HEPATOPROTECTIVE AND ANTIOXIDANT ACTIVITY OF Avicennia alba (BLUME) ON PARACETAMOL INDUCED HEPATOTOXICITY IN RATS

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    Objective: To study the hepatoprotective activity of ethanolic extracts of Avicennia alba leaves against paracetamol induced liver damage in rats. Methods: Hepatotoxicity was induced by paracetamol and the biochemical parameters such as serum aspartate amino transferase (AST), alkaline phosphatase (ALP), alanine amino transferase (ALT) and total bilirubin (SB) and the antioxidant such as Superoxide dismutase (SOD), Catalase (CAT), Glutathione Peroxidase (GPx), Glutathione (GSH), Vitamin-C & E and Thiobarbituric acid reactive substances (TBARS) were recorded and histopathological changes in liver were studied along with silymarin as standard hepatoprotective agents. Results: The phytochemical investigation of the extracts showed presence of alkaloids, flavonoids, tannins, terpenoids, proteins and steroids. Treatment with herbal extract to paracetamol administered rats caused a significant reduction in the values of AST, ALP, ALT and total bilirubin (P < 0.05) almost comparable to silymarin. The hepatoprotective was confirmed by histopathological examination of the liver tissue of control and treated animals. Conclusion: From the results it can be concluded that A.alba leaves possesses hepatoprotective effect against paracetamol-induced liver damage in rats

    Synthesis, spectral characterisation and pharmacological studies on Co(II), Ni(II), Cu(II) and Zn(II) bis-Schiff base complexes derived from 4-hydroxybenzohydrazide

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    915-926The transition metal(II) chelates have been prepared by the reactions of bis-Schiff base ligands derived from 4-hydroxy benzohydrazide and isophthalaldehyde/ o-phthaldehyde in 1:1 metal to ligand ratio. The formed ligands and their metal complexes have been investigated by elemental analysis, different spectroscopic and thermal analyses techniques. The low molar conductance values give the non-electrolytic nature of the metal(II) chelates. From the spectroscopic observations of complexes, the molecular formula is found to be [M(Ln)2Cl2] (where M= Co(II), Ni(II), Cu(II) and Zn(II), n=1 and 2) and the tetradentate N2O2 donor sites of ligands is attached to the metal centre. The docking results predicts that the protein with ligands have good interaction energy. All formed complexes have efficient antibacterial activity than ligand for tested pathogens. The mode of binding interaction of ct-DNA and Cu(II) complexes gives the intercalative binding with hypochromism shifts using electronic titrations method. In electrophoresis, cleavages of PUC18DNA to cleave effectively with Cu(II) complexes in the presence of hydroxyl radicals. The antioxidant assay of DPPH radical scavenging activity of tested compounds shows good results, when compared to ascorbic acid as standard. The anticancer MTT assay of Cu(II) complexes tested against MCF-7 cancerous cells gives the promising therapeutic activity

    Quantum measurement arrow of time and fluctuation relations for measuring spin of ultracold atoms

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    The origin of macroscopic irreversibility from microscopically time-reversible dynamical laws—often called the arrow-of-time problem—is of fundamental interest in both science and philosophy. Experimentally probing such questions in quantum theory requires systems with near-perfect isolation from the environment and long coherence times. Ultracold atoms are uniquely suited to this task. We experimentally demonstrate a striking parallel between the statistical irreversibility of wavefunction collapse and the arrow of time problem in the weak measurement of the quantum spin of an atomic cloud. Our experiments include statistically rare events where the arrow of time is inferred backward; nevertheless we provide evidence for absolute irreversibility and a strictly positive average arrow of time for the measurement process, captured by a fluctuation theorem. We further demonstrate absolute irreversibility for measurements performed on a quantum many-body entangled wavefunction—a unique opportunity afforded by our platform—with implications for studying quantum many-body dynamics and quantum thermodynamics

    Властивості біокаталітичних мембран з іммобілізованою протеазою при ультрафільтрації молочної сироватки

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    За допомогою адсорбції або фільтрування розчину протеази крізь ультрафільтраційні C010 та P010 мембрани одержано біокаталітичні мембрани з іммобілізованим ферментом. Показано, що такі мембрани характеризуються значно вищою продуктивністю при ультрафільтрації молочної сироватки порівняно з вихідними мембранами завдяки здатності іммобілізованого ферменту розщеплювати білкові молекули, які акумулюються на поверхні мембрани і спричиняють її забруднення

    Topological atom optics and beyond with knotted quantum wavefunctions

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    Atom optics demonstrates optical phenomena with coherent matter waves, providing a foundational connection between light and matter. Significant advances in optics have followed the realization of structured light fields hosting complex singularities and topologically non-trivial characteristics. However, analogous studies are still in their infancy in the field of atom optics. Here, we investigate and experimentally create knotted quantum wavefunctions in spinor Bose–Einstein condensates which display non-trivial topologies. In our work we construct coordinated orbital and spin rotations of the atomic wavefunction, engineering a variety of discrete symmetries in the combined spin and orbital degrees of freedom. The structured wavefunctions that we create map to the surface of a torus to form torus knots, Möbius strips, and a twice-linked Solomon’s knot. In this paper we demonstrate close connections between the symmetries and underlying topologies of multicomponent atomic systems and of vector optical fields—a realization of topological atom-optics

    Biochemical characterization and 16s rRNA sequencing of different bacteria from textile dye effluents

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    Environmental pollution has been identified as a major problem in the modern world. Dyeing effluents have become a vital source of water pollution. Release of coloured textile effluents is undesirable in the aquatic environment as they reduce light penetration, thereby affecting aquatic life and limits utilization of the water media. In Tirupur, the textile factories discharge millions of litres of untreated effluents into the drains that eventually empty into river, Noyyal. The release of coloured compound into water bodies is undesirable not only because of their impact on photosynthesis of aquatic plants but also due to the carcinogenic nature of these dyes and their breakdown products. The ability of bacterial strains isolated from the dye effluent of textile mill sites. Morphological and biochemical characterization was done to identify isolates and was found to be Pseudomonas spp, Bacillus spp and Serattia spp. The isolated strains were finally identified by 16S rRNA sequence analysis. Bacteria are generally identified by 16S rRNA sequencing. The rRNA is the most conserved (least variable) gene in all cells. They were identified as Pseudomonas aeruginosa, Bacillus amyloliquefaciens and Serattia liquefaciens. The sequences were deposited in GENBANK. The accession numbers were KU041528, KU041530 and KU041531 respectively. The identification was conformed by 16S rRNA sequencing. Keywords: Textile Dye Effluents, Bacteria, 16S rRNA, NCBI

    Nature-inspired nano-additives for Biofuel application – A Review

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    The increasing demand and cost of conventional fuels have forced humanity to consider various alternative fuels. Low yield and massive cost are significant limitations in biofuel production. Nanotechnology has emerged as a prominent research area in the scientific community with a wide range of applications, including biofuels. This review discusses the specific approaches and methods to synthesize nanoparticles from natural materials. In addition, it summarizes the use of nanocatalyst, nano-additives and microbial enzymes to enhance biofuel properties and production processes. This review also highlights the effect of plant-based nanoparticles on diesel engines' combustion performance and emissions

    Phytochemical screening and GC–MS analysis of bioactive compounds present in ethanolic leaves extract of Silybum marianum (L).

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    Objective: To investigate the phytochemicals and GC-MS analysis of ethanol extracts of Silybum marianum. Methods: The air-dried leaves were powdered and subjected to selective sequential extraction using solvents of increasing polarity through percolation, ethanol to obtain an ethanolic extract. Then, each of the extracts was further subjected to gas chromatography-mass spectrometry. Results: Qualitative determination of the different biologically active compounds from crude extracts of Silybum marianum using gas chromatography-mass spectrometry revealed different types of high and low molecular weight chemical entities with varying amounts present in each of the extracts. These chemical compounds are considered biologically and pharmacologically important. Conclusions: The study established the chemical composition and anticancer activity of the plant. Keywords: Silybum marianum, Phytochemicals screening, GC–MS analysis, Bioactive compounds
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