Variability of scatterometer based surface vorticity over Arabian Sea and its use in monsoon onset forecasting

This paper presents the results of the study undertaken to investigate the changes in the surface wind and vorticity fields over south Arabian Sea and adjoining north Indian Ocean and their association with monsoon onset over Kerala. For this purpose QuikSCAT daily gridded data of recent 10 years (2000-2009) have been utilized. The results show that there is a rising trend in the surface wind speed and vorticity over south Arabian Sea about 4-7 days before the monsoon onset over Kerala. Thus, the rising trends in the surface wind speed and vorticity over south Arabian Sea seem to be a good precursor of monsoon onset over Kerala. Continuous monitoring of Oceansat-2 scatterometer surface wind and vorticity fields over south Arabian Sea and adjoining north Indian Ocean during 15th May to 15th June could provide predictive indications of monsoon onset over Kerala on medium range scale.

Detection of a new methylamine (CH3NH2) source: Candidate for future glycine surveys

Interstellar glycine (NH2CH2COOH), the simplest amino acid, has long been sought in studying a possible relation between the Universe and origin of life. In the last 40 or so years all surveys of glycine have failed; an alternative strategy would be to search for precursor(s) to glycine. Such studies of precursors would be crucial prior to conducting sensitive surveys with ALMA. Laboratory studies have suggested that CH3NH2 is a possible precursor to glycine. Further theoretical study also suggests that the CH2NH2 radical that can be formed from CH3NH2 through photodissociation can be a good precursor to glycine. Thus, we have looked for CH3NH2 towards several hot core sources using the Nobeyama 45 m radio telescope, and succeeded in finding a new CH3NH2 source, G10.47+0.03, with a fractional abundance of 1.5 ± 1.1 × 10−8; at the time of writing, this source is the most abundant source of CH3NH2 ever known. We found that the observed abundance of CH3NH2 agrees fairly well with the theoretical value predicted by R. T. Garrod (2013, ApJ, 765, 60). The detectability of interstellar glycine is discussed.

The Sun’s polar magnetic field: datasets, proxies and theoretical issues

The polar magnetic field of the Sun is a manifestation of certain aspects of the dynamo process and is a good precursor for predicting a sunspot cycle before its onset. Although actual synoptic measurements of this field exist only from the mid-1970s, it has now been possible to determine its evolution from the beginning of the twentieth century with the help of various proxies. The recently developed 3D kinematic dynamo model can study the build-up of the Sun’s polar magnetic field more realistically than the earlier surface flux transport model.

Substituent Effects of 2-Pyridones on Selective O-Arylation with Diaryliodonium Salts: Synthesis of 2-Aryloxypyridines under Transition­-Metal-Free Conditions

An efficient transition-metal-free strategy to synthesize 2-aryloxypyridine derivatives has been developed by a selective O-arylation of 2-pyridones with diaryliodonium salts. The reaction was compatible with a series of functional groups for 2-pyridones and diaryliodonium salts such as halides, nitro, cyano, and ester groups. The substituents at the C6-position of 2-pyridones favored O-arylation products because of steric hindrance. The reaction was easily performed on a gram-scale and 6-chloro-2-pyridone was a good precursor to access various unsubstituted 2-aryloxypyridines by dehalogenation. A P2Y1 lead compound analogue could be prepared in good yield over two steps.

From optimized monovalent ligands to size-controlled dendrimers: an efficient strategy towards high-activity DC-SIGN antagonists

This short review describes our work on the development of dendrimeric antagonists of DC-SIGN, a dendritic cells (DCs) receptor recognizing highly mannosylated structures and primarily involved in the recognition of viruses such as HIV. The structure of pseudo-di-mannoside and pseudo-tri-mannoside compounds was first finely modified to obtain DC-SIGN ligands that were more stable and selective than mannose. Their DC-SIGN affinity differences were amplified once presented on multivalent dendrimer-like scaffolds, including poly-alkyne terminated and phenylene-ethynylene rod-like ones. Libraries of mannosylated dendrimers were synthesized, improving their stability and maximizing their monodispersity. The effect of the dendrimers valency, structure, and size on DC-SIGN affinity and antiviral potency was investigated. Both the valency and the topology of the architectures were revealed as key parameters for activity optimization, together with the intrinsic affinity of the monovalent ligand. The stability, rigidity, and length of the scaffolds were also tuned. The design of geometrically adapted scaffolds afforded one of the most potent inhibitors of DC-SIGN mediated HIV infections to date. This monodispersed, not cytotoxic, and highly active compound was also tested with DCs; its internalization into endolysosomal compartments and its ability to induce the overexpression of signaling molecules makes it a good precursor to produce pathogen-entry inhibitors with immunomodulant properties.

Influence of La2O3composition in MgO–La2O3mixed oxide-supported Co catalysts on the hydrogen yield in glycerol steam reforming

Partially Mg-substituted LaCoO3perovskite is a good precursor, for the generation of cobalt nanoparticle derived under the reduction atmosphere. The La2O2CO3phase formed is more efficient in removing the carbon from the cobalt active site.

Changes in Tropical Pacific Thermocline Depth and Their Relationship to ENSO after 1999

The characteristics of El Niño–Southern Oscillation (ENSO) variability have experienced notable changes since the late 1990s, including a breakdown of the zonal mean upper-ocean heat content as a precursor for ENSO. These changes also initiated a debate on the role of thermocline variations on the development of ENSO events since the beginning of the twenty-first century. In this study, the connection between thermocline variations and El Niño and La Niña events is examined separately for the 1980–98 and 1999–2012 periods. The analysis highlights the important role of thermocline variations in modulating ENSO evolutions in both periods. It is found that thermocline variation averaged in the central tropical Pacific, including both equatorial and off-equatorial regions, is a good precursor for ENSO evolutions before and after 1999, while the traditional basinwide mean of equatorial thermocline variation is a good precursor only before 1999. The new precursor, including both high-frequency variability in equatorial regions and low-frequency variability in off-equatorial regions, is found to be indicative of multiyear persistent warm and cold conditions in the tropical Pacific. Further, it is found that the strength of the subtropical cells (STCs) interior mass transport in both hemispheres increased rapidly around the late 1990s. It is proposed that the strengthened STC interior transports provide a pathway for the enhanced influence of off-equatorial thermocline variations on the development of ENSO events after 1999.

Expedient synthesis of 1,6-anhydro-α-D-galactofuranose, a useful intermediate for glycobiological tools

A new and efficient three-step procedure for the synthesis of 1,6-anhydro-α-D-galactofuranose is described. The key step involves the formation of the galactofuranosyl iodide by treatment of per-O-TBS-D-Galf with TMSI, the selective 6-O-desilylation by an excess of TMSI, and the simultaneous nucleophilic attack of the 6-hydroxy group on the anomeric carbon, with the iodide as a good leaving group. This compound is a good precursor for building blocks for the construction of 1→6 linkages.

Effect of Activated Time on the Properties of ZnO/AC Composites from Spent Catalysts

After being subjected to thermal treatment by microwave, a carbon-based spent catalyst from vinyl acetate synthesis has been proved to be a good precursor for the production of ZnO/activated carbon (AC) composites. Different operating activated times were found to have effect on the properties of the composites. As the activated time rises, the surface area of the activated carbon that is acting as the catalyst support increases due to the decomposition of the organic deposits that are clogging the porous structure. XRD was used to evaluate the transformation of zinc acetate to zinc oxide after thermal treatment. Both the iodine adsorption capacity and the yield of the resulting composites were calculated and SEM-EDX analysis was used to evaluate the changes in surface morphology.

Synthesis of a bowl-type dodecavanadate by the coupling reaction of alkoxohexavanadate and discovery of a chiral octadecavanadate

A new route to an alkoxohexavanadate species leads to the isolation of a bowl-type dodecavanadate without a guest molecule in the cavity. The 1D tetravanadate, [V4O11]2-, is a good precursor for the alkoxohexavanadate, [V6O13(OCH3)6]2-, which is then utilized for the [V6 + V6] coupling reaction to form the dodecavanadate, [V12O42]4-, with a capped dichloromethane molecule at the cavity entrance. We also obtained structural information on a newly discovered octadecavanadate, [V18O46(NO3)]5-,in both the solid and solution states through extended X-ray absorption fine structure (EXAFS) studies. The existence of a chiral inorganic species in acetonitrile with double-stranded V8 chains was confirmed through EXAFS oscillations.