[en] The present CuBr-catalyzed method of protection of carbonyl compounds as thioacetals is a novel, generally applicable, mild, cost-effective, operational simplicity and convenient one, where the catalyst could be readily recovered and reused thus making this procedure environmentally benign. Furthermore, the relatively slow reaction rate of ketones allows for chemoselective protection of aldehydes in the presence of ketones, making this is an important tool in synthetic organic chemistry. Efforts to expand the scope of the reaction in green solvents and deprotection of thioacetals are currently underway in our laboratory. Protections of carbonyl groups as thioacetals are quite often a necessary requirement in the synthesis of multifunctional organic molecules. Thioacetals are quite stable toward a wide variety of reagents and are useful in organic synthesis as acyl carbanion equivalents in C-C bond-forming reactions. Further, the use of thioacetals as blocking groups has allowed a new strategy for the electrophilic substitution on the carbonyl compound

[en] p-Nitrobenzoic acid was found to be the versatile Bronsted organic acid promoter among the carboxylic acids tested for the preparation of 1,5-benzodiazepine derivatives from a wide range of substituted o-phenylenediamines and ketones. The corresponding products were obtained in good isolated yields (62-92%) under mild conditions using acetonitrile as solvent at ambient temperature. Further, the reagent could be easily recovered and reused. (author)

[en] An integrated geophysical approach was attempted for uranium exploration in Jamiri area, Arunachal Pradesh, using the techniques of magnetic, self-potential (SP) and resistivity profiling, coupled with solid state nuclear track detection (SSNTD), to delineate favourable structures controlling uranium mineralisation in phyllitic quartzites and quartzites of the Precambrian Daling formation. Three promising zones of uranium mineralisation were recognised based on integrated results from these surveys. Magnetic survey identified lithologic contacts and faults in the area. A high-order SP anomaly of -900 millivolts was observed near the contact of phyllites in the east and phyllitic quartzites in the west. A very low resistivity of 1.0 ohm.m and high SSNTD values of 120 tracks/mm² over a background of 20 to 30 tracks/mm² were also recorded near this contact. These anomalies are characteristic of a fault that channelises radon and gives low resistivities. The SP anomaly may indicate sulphide mineralisation, and hence, uranium mineralisation in this contact zone may be associated with sulphides. The phyllitic quartzites west of this contact are characterised by magnetic highs ranging from 540 to 900 gammas. Here, SP anomalies are also small closures of -80 to -100 mV. The SSNTD values range between 100 and 120 tracks/mm². This rock unit (phyllitic quartzite) appears to host uranium mineralisation along with sulphides at some places where radon anomalies are high. A fault in the western portion of the area interpreted from the magnetic map separates phyllitic quartzites in the east and quartzites to its west. The faulted contact is characterised by a high SP gradient and SSNTD anomalies of 100 to 140 tracks/mm². This contact may also be promising for uranium mineralisation at depth. (author). 10 refs., 8 figs

[en] Quantum gate teleportation utilises shared entanglement and local operations and classical communication to mediate logical gate operations between qubits that cannot directly interact, making it an essential tool for the modular quantum computing architecture [1]. In this work, we demonstrate the deterministic teleportation of a controlled-Z gate between two 43CA+ hyperfine clock qubits located in separated trapped-ion quantum processors, measuring an average gate fidelity of 86.2(8) %. We achieve this by combining state-of-the-art remote entanglement between two 88Sr+ network ions [2] and local mixed-species entangling gates to mediate an interaction between co-trapped 43Ca+ memory ions [3]. We discuss how this system enables distribution of a circuit comprising multiple instances of gate teleportation across our quantum network. Our results pave the way for distributed quantum computation based on networks of trapped-ion quantum processors. [1] D. Gottesman, I. Chuang, Demonstrating the viability of universal quantum computation using teleportation and single-qubit operations. Nature 402, 390–393 (1999). [2] L. Stephenson, D. Nadlinger, B. Nichol, S. An, P. Drmota, T. Ballance, K. Thirumalai, J. Goodwin, D. Lucas, and C. Ballance, High-Rate, High-Fidelity Entanglement of Qubits Across an Elementary Quantum Network, Physical Review Letters 124, 110501 (2020). [3] P. Drmota, D. Main, D. Nadlinger, B. Nichol, M. Weber, E. Ainley, A. Agrawal, R. Srinivas, G. Araneda, C. Ballance, and D. Lucas, Robust Quantum Memory in a Trapped-Ion Quantum Network Node, Physical Review Letters 130, 090803 (2023).

[en] Over the past few decades, advancements in optical atomic clocks have made it possible to measure time and frequency with unprecedented stability and systematic uncertainty [1,2]. Precision frequency comparisons between macroscopically separated clocks have applications in geodesy [3], probing variations in fundamental constants, and in dark matter searches [4]. Until now, most previous frequency comparisons between different clocks have been done on independent systems, which are limited by the standard quantum limit (SQL). In contrast, a set of entangled atomic clocks can surpass the SQL to reach the Heisenberg limit -- the ultimate precision limit in quantum theory -- wherein a system of N entangled clocks sees an improvement of √N in its stability. We previously demonstrated this enhancement in a network of two 88Sr+ clocks [5] on the 674 nm 5S₁/2↔4D₅/2 quadrupole transition using Ramsey spectroscopy, reaching a fractional frequency uncertainty of 10^-15, mainly limited by the short probe duration of 20 ms due magnetic field fluctuations. To reach lower uncertainties, we are setting up the next generation of the experiment wherein we map the remote Sr-Sr entanglement onto two 43Ca+ ions. The 729 nm 43Ca+ |4S₁/2, F=4, m_F=4> ↔ |3D₅/2, F=4, m_F=3> optical clock transition is field-insensitive at 4.96 G, enabling probe durations of over 500 ms, which is comparable to the start-of-the-art clocks [1]. This improves the fractional frequency uncertainty on each measurement and thus yields a lower overall instabililty. We will present progress towards these clock experiments, including the setup of a 729 nm laser system locked to a high finesse cavity, as well as fibre noise cancellation on 20 m of fibre length. References [1]. S. M. Brewer et al., Phys. Rev. Lett. 123, 33201 (2019). [2]. E. Oelker et al., Nat. Photon. 13, 714–719 (2019) [3]. T. E. Mehlstaubler et al., Rep. Prog. Phys. 81, 064401 (2018). [4]. M. S. Safronova et al., Rev. Mod. Phys. 90, 025008 (2018). [5]. B. C. Nichol et al., Nature 609, 689–694 (2022)

[en] Cerebrotendinous xanthomatosis is a rare genetic disorder. We present and discuss the clinical, radiological, and histopathologic findings in a 36-year-old woman who had juvenile cataract, childhood diarrhea, mental retardation, cerebellar ataxia, and bilateral Achilles tendon xanthomas. She was thoroughly investigated radiologically and biopsy confirmed the diagnosis of xanthomas

[en] In the unlikely event of core disruptive accident in sodium cooled fast reactors, the reactor containment building would be bottled up with sodium and fission product aerosols. The behavior of these aerosols is crucial to estimate the in-containment source term as a part of nuclear reactor safety analysis. In this work, the evolution of sodium aerosol characteristics (mass concentration and size) is simulated using HAARM-S code. The code is based on the method of moments to solve the integro-differential equation. The code is updated to FORTRAN-77 and run in Microsoft FORTRAN PowerStation 4.0 (on Desktop). The sodium aerosol characteristics simulated by HAARM-S code are compared with the measured values at Aerosol Test Facility. The maximum deviation between measured and simulated mass concentrations is 30% at initial period (up to 60 min) and around 50% in the later period. In addition, the influence of humidity on aerosol size growth for two different aerosol mass concentrations is studied. The measured and simulated growth factors of aerosol size (ratio of saturated size to initial size) are found to be matched at reasonable extent. Since sodium is highly reactive with atmospheric constituents, the aerosol growth factor depends on the hygroscopic growth, chemical transformation and density variations besides coagulation. Further, there is a scope for the improvement of the code to estimate the aerosol dynamics in confined environment

[en] Uranium mineralisation is reported in the basement fracture if Sambalpur granitoids in Dulapali area of Raigarh district, M.P. VLF-EM surveys are conducted using Scintrex IGS-2/ VLF-4 equipment to demarcate the spatial locations of these fractures filled with ferruginous breccia of magnetite, hematite, ilmetite, pyrite and chalcopyrite vis-a-vis, the EM conductors. Three parameters - vertical in-phase (DZR), vertical out-of-phase (DZI) normalised by horizontal magnetic field (Hy) and VLF-EM resistivity (r_a) are recorded and analysed. (author)

[en] Uranium mineralization hosted by ferruginous brecciated quartzites occurs in a structurally controlled geological environment near Laimura village, Sambalpur district, Orissa. Detailed geophysical surveys comprising magnetic, resistivity and induced polarization (IP) methods, conducted over an area of 1.7 km², provides information regarding structural disposition of the ferruginous brecciated quartzites. The low-pass filtered magnetic map indicated well-defined magnetic sources along an east-west trending fault zone at depth and few subsidiary faults, displacing these magnetic bodies. The indistinct lithic boundaries of shales, ferruginous quartzites and massive are well delineated from the resistivity values. Qualitative interpretation of IP parameters further confirm them. Resistivity pseudo-sections reveal the depth continuity of the brecciated quartzites. (author)

[en] Detailed electromagnetic (Turam) survey was conducted over Rohil-Khatundra tract of Sikar district, Rajasthan where fracture controlled and albitite-hosted uranium mineralisation in association with sulphides occur in the rocks of Delhi Super Group. The conductors identified from this survey persist over a strike length of 1 km as discrete parallel bands, which are intercepted in many boreholes and found to be associated closely with significant uranium mineralization. Study of EM response at two frequencies of 105 and 315 Hz revealed persistency of these conductors at depth. Also, Induced Polarization (l.P.)/Resistivity survey, in the village portion of Rohil where EM survey could not be taken up due to cultural noise, is utilized effectively. The above results are discussed in detail in this paper. (author)