Raman spectroscopy of graphene on different substrates and influence of defects

We show the evolution of Raman spectra with number of graphene layers on different substrates, SiO$_{2}$/Si and conducting indium tin oxide (ITO) plate. The G mode peak position and the intensity ratio of G and 2D bands depend on the preparation of sample for the same number of graphene layers. The 2D Raman band has characteristic line shapes in single and bilayer graphene, capturing the differences in their electronic structure. The defects have a significant influence on the G band peak position for the single layer graphene: the frequency shows a blue shift upto 12 cm$^{-1}$ depending on the intensity of the D Raman band, which is a marker of the defect density. Most surprisingly, Raman spectra of graphene on the conducting ITO plates show a lowering of the G mode frequency by $\sim$ 6 cm$^{-1}$ and the 2D band frequency by $\sim$ 20 cm$^{-1}$. This red-shift of the G and 2D bands is observed for the first time in single layer graphene.Comment: 6 pages, 8 figure

Effects of Phase Transition induced density fluctuations on pulsar dynamics

We show that density fluctuations during phase transitions in pulsar cores may have non-trivial effects on pulsar timings, and may also possibly account for glitches and anti-glitches. These density fluctuations invariably lead to non-zero off-diagonal components of the moment of inertia, leading to transient wobbling of star. Thus, accurate measurements of pulsar timing and intensity modulations (from wobbling) may be used to identify the specific pattern of density fluctuations, hence the particular phase transition, occurring inside the pulsar core. Changes in quadrupole moment from rapidly evolving density fluctuations during the transition, with very short time scales, may provide a new source for gravitational waves.Comment: 9 pages, 1 figure. arXiv admin note: substantial text overlap with arXiv:1412.427

Introduction to OneCGIAR Genetic Innovations Action Area & the Accelerated Breeding Initiative

Presentation given by Biswanath Das during a partner meeting that took place in Istanbul, Turkiye, 13-15 December 2022 between ICARDA management and NARES leaders, selected based on their active role in requesting, using, and promoting ICARDA’s Genetic Innovations. ICARDA sought guidance from its NARES partners to determine if the portfolio of Genetic Innovation research defined in the 2017-2026 ICARDA Strategy is still significant to the 2030 horizon set by the CGIAR. As part of this initial engagement in CWANA++, this meeting provided the first step towards further inclusion of other involved CGIAR Centers. In their initial deliberations, NARES have expressed the following considerations to guide this prioritization work: food security, climate change, and strategies to support effective management of agriculture and food systems

Studies on phytochemicals: Part XVII-Phenolics from the roots of Jatropha gossypifolia

1077-107

Kinetic Insight on Improved Chemi-Resistive Response of Hydrothermal Synthesized Pt Loaded TiO2 Nano-rods Toward Vapor Phase Isopropanol

Flower like microstructure composed of eccentrically grown vertically aligned titania nano-rods is prepared through spherical carbon template mediated hydrothermal route. Mechanistic pathways for the growth of said esthetic architecture is proposed by studying their phase formation behavior and morphological features. Chemi-resistive type sensing properties of prepared titania flowers for the detection of isopropanol are studied by varying the sensor operating temperature (225–300°C) and vapor concentration (10–200 ppm). Distinguishable sensitivity of titania flowers is identified for the detection of even 10 ppm isopropanol. Catalytic amount of Pt nano-particles (synthesized through chemical method) are introduced over prepared flower like titania to improve further their sensitivity. The plausible isopropanol sensing mechanism over TiO2 flowers as well as influence of operating temperature and role of Pt nanoparticles as chemical sensitizer in enhancing the response is explained. The current response transients of both the TiO2 flowers and their Pt modified counterpart for detecting low concentration (10–50 ppm) of isopropanol are modeled in accordance to Langmuir-Hinshelwood reaction mechanism and the rate constants for the respective surface reactions are estimated. The higher rate constant for the interaction of isopropanol over titania flowers than Pt modified counterparts is explained using the concept of decaying depleted layer during sensing

A simple formal stereoselective synthesis of Herbarumin III

A formal stereoselective synthesis of Herbarumin III has been accomplished starting from butanal involving Maruoka asymmetric allylation, diastereoselective iodine-induced electrophilic cyclization and conversion of iodocarbonate into syn-epoxy alcohol as the key steps

A simple stereoselective synthesis of (+)-[6]-gingerdiol

A simple stereoselective synthesis of (+)-[6]-gingerdiol has been accomplished starting from vanillin. The synthetic sequence involves Mouroka allylation, diasterioselective iodine induced electrophilic cyclization and ring-opening of an epoxide as the key steps