The first total synthesis of neohelmanticins A–D,amino derivatives of the 1,2-dihydroxypropane core and biological evaluation

A concise total synthesis of neohelmanticins A–D has been accomplished in 15 steps starting from commercially available gallic acid. Swern oxidation conditions, a Grignard reaction, Sharpless kinetic resolution, and regioselective ring opening of an epoxide with lithium aluminum hydride (LAH) are the key features to install the basic core, dihydroxy phenyl propane 2. One hydroxyl group of this core was esterified with tiglic acid followed by the oxidation and esterification with corresponding acids to yield neohelmanticins A–D.     

Comment on: “Universal relation between spectroscopic constants”

Kaur and Mahajan [1] have claimed to derive a universal relation InG = 1.91578(±0.09727) + 0.97111(±0.03809) In Δ between the Sutherland parameter Δ(=ω _er _e ² /2D_e) and the dimensionless parameterG(= 8ω _ex_e/B_e) for the ground as well as excited electronic states of diatomic molecules. Validity of this relation is checked and we find that the relation is not correct. Next, we checked the validity of the relation Δ = 2.2r_e for the alkali group diatomic molecules. This relation is also found not to be correct.     

A study on the heat-treatments of nanocrystalline nickel substituted BaW hexaferrite produced by low combustion synthesis method

The novel low temperature combustion synthesis (LCS) method for the preparation of nanocrystalline W-type BaW hexaferrite i.e. BaNi₂Fe₁₆O₂₇ has been carried out by citrate precursor using the sol-to-gel (S–G) followed by gel-to-nanocrystalline (G–N) conversion. Decomposition behaviors and the phases associated therein are investigated by means of thermal analysis (DTA/DTG/TG) and XRD, respectively. Atomic absorption spectroscopy (AAS) has been used to determine the elemental analysis in different conditions. Surface morphology of the nonporous ultra fine particles have been examined by SEM. The TEM micrographs show that the particles of the size of 10 nm were seemed to be agglomerated in the ‘as synthesized’ condition. Room temperature Fe-57 Mossbauer spectrum, MS has showed doublet of ‘as synthesized’ nanocrystalline powder that indicates the superparamagnetic behavior of the material. This effect is further confirmed by vibrating sample magnetometer (VSM) wherein it was noticed that the magnetic field (10 KG max) did not have any effect on the material. The material was annealed at 400, 700 and 1000 °C in the furnace for 4 h. The grain size is found to increase from 10 to 70 nm after annealing at 1000 °C for 4 h. MS after annealing at 700–1000 °C for 4 h, showed that the doublets of ‘as synthesized’ is further resolved into broad sextets due to the presence of both superparamagnetic and ferrimagnetic particles, in the wide size range from 10 to 70 nm. Only slight increase in particle size (from 10 to 15 nm) is noticed after the heat-treatment for 1–3 and 5 min in microwave oven (2.45 GHz with 760 W) but with predominant phase changes. TEM after the heat treatment revealed the presence of microcrystalline nature of grains of the size ∼70 nm. The transformation of the magnetic properties i.e. from superparamagnetic to ferrimagnetic behaviour after heating in microwave oven has been revealed by hysteresis loops under VSM study. The saturation magnetisation, M_s after heat treatment has been seen to increase from 26.7 to 44.5 emu/gm. Remanence and coercivity have also increased four and seven times, respectively. M_s of the as synthesised hexaferrite nano powder and heat-treated powder in microwave oven for 5 min show doublets, confirming the presence of superparamagnetic relaxation in the nano particles as only slight increase in the particle size is associated with the heat treatment.     

Collision of optical solitons with Kerr law nonlinearity

The intra-channel collision of optical solitons, with Kerr law nonlinearity, is studied by the aid of quasi-particle theory. The perturbation terms considered in this paper are all of Hamiltonian type. It is shown that the soliton–soliton interaction can be suppressed in the presence of these perturbations, namely, the self-steepening, the third-order dispersion, the fourth-order dispersion and the frequency separation between the soliton carrier and the gain-center frequency. The prediction of quasi-particle theory are fully confirmed by direct numerical simulations.     

Stochastic perturbation of non-Kerr law optical solitons

The dynamics of optical solitons with non-Kerr law non-linearities, in presence of stochastic perturbation terms, is studied in this paper. The Langevin equations are derived and it is proved that the solitons travel through a fiber with a fixed mean velocity. The non-linearities that are considered here are the power law, parabolic law and the dual-power law types.     

Quasi-Particle Theory of Alfven Soliton Interaction in Plasmas

The collision of solitons due to Alfven waves in plasmas is studied in this paper by the aid of quasi-particle theory. The suppression of the interaction of solitons, in presence of the perturbation terms, is acheived by means of this theory. The perturbation terms that are considered in this paper are nonlinear damping, finite conductivity and Landau damping. The numerical simulations support the theory that was developed. PACS Codes: 02.30.Ik, 02.30.Jr, 52.35.Sb.     

Gravitational Faraday Effect Produced by a Ring Laser

Using the linearized Einstein gravitational field equations and the Maxwell field equations it is shown that the plane of polarization of an electromagnetic wave is rotated by the gravitational field created by the electromagnetic radiation of a ring laser. It is further shown that this gravitational Faraday effect shares many of the properties of the standard electromagnetic Faraday effect. An experimental arrangement is then suggested for the observation of this gravitational Faraday effect induced by the ring laser.     

Soliton Perturbation Theory for the Compound KdV Equation

The soliton perturbation theory is used to study the solitons that are governed by the compound Korteweg de-Vries equation in presence of perturbation terms. The adiabatic parameter dynamics of the solitons in presence of the perturbation terms are obtained. AMS Codes: 35Q51; 35Q53; 37K10. PACS Codes: 02.30.Jr; 02.30.Ik.     

Relative quantitation of peptides in wild-type and Cpe(fat/fat) mouse pituitary using stable isotopic tags and mass spectrometry

Cpe(fat/fat) mice have a point mutation in the coding region of the carboxypeptidase E gene that renders the enzyme inactive. As a result, these mice have reduced levels of several neuropeptides and greatly increased levels of the peptide processing intermediates that contain C-terminal basic residues. However, previous studies examined a relatively small number of neuropeptides. In the present study, we used a quantitative peptidomics approach with stable isotopic labels to examine the levels of pituitary peptides in Cpe(fat/fat) mice relative to wild-type mice. Pituitary extracts from mutant and wild type mice were labeled with the stable isotopic label [3-(2,5-dioxopyrrolidin-1-yloxycarbonyl)propyl]trimethylammonium chloride containing nine atoms of hydrogen or deuterium. Then, the two samples were pooled and analyzed by liquid chromatography/mass spectrometry (LC/MS). The relative abundance of peptides was determined from a comparison of the intensities of the heavy and light peaks. Altogether, 72 peptides were detected in the Cpe(fat/fat) and/or wild-type mouse pituitary extracts of which 53 were identified by MS/MS sequencing. Several peptides identified in this analysis represent previously undescribed post-translational processing products of known pituitary prohormones. Of the 72 peptides detected in pituitary, 17 were detected only in the Cpe(fat/fat) mouse extracts; these represent peptide processing intermediates containing C-terminal basic residues. The peptides common to both Cpe(fat/fat) and wild-type mice were generally present at 2-5-fold lower levels in the Cpe(fat/fat) mouse pituitary extracts, although some peptides were present at equal levels and one peptide (acetyl beta-endorphin 1-31) was increased approximately 7-fold in the Cpe(fat/fat) pituitary extracts. In contrast, acetyl beta-endorphin 1-26 was present at approximately 10-fold lower levels in the Cpe(fat/fat) pituitary, compared with wild-type mice. The finding that many peptides are substantially decreased in Cpe(fat/fat) pituitary is consistent with the broad role for carboxypeptidase E in the biosynthesis of numerous neuropeptides.     

Design of photocleavable lipids and their application in liposomal "uncorking"

The design of o-nitrobenzyl containing photocleavable lipid-amino acid conjugates, and their application in liposomal uncorking are described.