CCSfind: A tool for chemically informed LC-IM-MS database building

In addition to providing critical knowledge of the accurate mass of ions, ion mobility-mass spectrometry (IM-MS) delivers complementary data relating to the conformation and size of ions in the form of an ion mobility spectrum and derived parameters, namely, the ion's mobility (K) and the IM-derived collision cross section (CCS). However, the maximum amount of information obtained in IM-MS measurements is not currently transferred into analytical databases including the full mobility spectra (CCS distributions) as well as capturing of additional ion species (e.g., adducts) into the same compound entry. We introduce CCSfind, a new tool for building comprehensive databases from experimental IM-MS measurements of small molecules. CCSfind allows predicted ion species to be chosen for input chemical formulae, which are then targeted by CCSfind after parsing open source mzML input files to provide a unified set of results within a single data processing step. CCSfind can handle both chromatographically separated isomers and IM separation of isomeric ions (e.g., “protomers” or conformers of the same ion species) with simple user control over the output for new database entries in SQL format. Files of up to 1 GB can be processed in less than 2 min on a desktop computer with 32 GB RAM with computational time scaling linearly with the size of the input mzML file or the number of input molecular formulae. Results are manually reviewed, annotated with experimental settings, before committing the database where the full dataset can be retrieved.     

Effect of density variation on the Sm A–I phase transition properties

Based on a thermodynamic model, we investigate how the density variation influences the smectic (Sm A)–isotropic (I) phase transition. We find that the density variation shifts the smectic A–isotropic transition temperature, however, first-order nature of the transition remains the same. Here, we also examine the effect of high pressure on the thermodynamic quantities. The present analysis shows that the pressure strongly influences the enthalpy and density step at the clearing transition. The pressure dependence of the thermodynamic properties is incorporated through the pressure dependent second Landau coefficient and the coefficients which couple the nematic and smectic order parameters to the density. We find a close agreement between theoretical and experimental results. Furthermore, we discuss the implications of the results for achiral liquid crystals.     

DSC studies on the curing kinetics of chitosan–alanine using glutaraldehyde as crosslinker

The curing of chitosan–alanine with glutaraldehyde as curing agent in the presence of Chlorpheniramine Maleate (CPM) is carried out with the help of differential scanning calorimeter (DSC). The effect of concentration of chitosan and percentage of crosslinker on the curing is studied at a rate of 5 °C/min. Cure kinetics are measured from 30 to 200 °C at four different heating rates (3, 5, 7 and 10 °C/min). It is observed that the crosslinking of chitosan–alanine is an exothermic process which results in a positive peak in the curves. An increase in activation energy (E _α) is observed with extent of conversion.     

Ionic liquid catalyzed synthesis of 7-phenyl-1,4,6,7-tetrahydro-thiazolo[5,4-d]pyrimidine-2,5-diones

A simple, green and catalyst free one pot synthesis of 7-phenyl-1,4,6,7-tetrahydro-thiazolo[5,4-d]pyrimidine-2,5-diones via a multicomponent reaction between thiazolidine-2, 4-dione (TZD), aromatic aldehyde and urea analogues is described. The ionic liquid has been used as a solvent as well as catalyst for this reaction. This reaction proceeded smoothly in good to excellent yields and offered several other advantages including short reaction time, simple experimental workup procedure and no by-products.     

Investigation of encapsulation of insulin biotemplate within C-methylresorcin[4]arenes

Solution structure of insulin templated C-methyl resorcin[4]arene nanocapsules has been investigated using neutron scattering. The insulin biotemplate has enhanced the limits of encapsulation and enabled formation of a larger spherical molecular host.     

Unusual room temperature CO(2) uptake in a fluoro-functionalized MOF: insight from Raman spectroscopy and theoretical studies

We herein report an unusual CO(2) adsorption behavior in a fluoro-functionalized MOF {[Zn(SiF(6))(pyz)(2)]·2MeOH}(n) (1) with a 1D channel system, which is made up of pyrazine and SiF(6)(2-) moieties. Surprisingly, desolvated 1 (1') adsorbs higher amounts of CO(2) at 298 K than at 195 K, which is in contrast to the usual trend. Combined Raman spectroscopic and theoretical studies reveal that slanted pyrazine rings in 1' with an angle of 17.2° with respect to the (200) Zn(ii)-Si plane at low temperature block the channel windows and thus reduce the uptake amount.     

Molecular dynamics in chloronitrobenzenes using NQR data

The torsional frequencies have been rigorously evalulated in the compounds 1,2,4,5-tetrachloro-3,6-dinitrobenzene and 1,3,5-trichloro-2,4-dinitrobenzene over an extended temperature range (77K–392K) using the experimental results of NQR and crystal structure data. The values have been compared with those obtained by using the X-ray thermal parameters.     

Fungicidal,bactericidal and antifertility activities of diorganosilicon(IV) complexes derived from benzothiazolines

Synthetic, structural and biological aspects of trigonal-bipyramidal, Me₂S(N—S)CI and octahedral, Me₂Si(N—S)₂ types of diorganosilicon(IV) complexes of heterocyclic benzothiazolines (N—SH) are described. The complexes were characterized by elemental analysis, molecular weight determination, conductance measurements and electronic, infrared, ¹H and ¹³C NMR spectroscopic studies. Some ligands and their corresponding dimethylsilicon(IV) complexes have been tested for their effects on several pathogenic fungi and bacteria and found to be quite active in this respect. Antifertility activity in male mice of some representative ligands and their silicon complexes was also evaluated and discussed.     

Combined convection along a non-isothermal wedge in a porous medium

A boundary layer analysis has been presented for the combined convection along a vertical non-isothermal wedge embedded in a fluid-saturated porous medium. The transformed conservation laws are solved numerically for the case of variable surface temperature. Results are presented for the details of the velocity and temperature fields as well as the Nusselt number. The wedge angle geometry parameter m ranged from 0 to 1.