Viscosities of quaternary liquid solutions

Viscosity of quaternary non-electrolyte solution carbon tetrachloride+ cyclohexane+benzene+toluene has been experimentally determined at 25°C. Experimental results of viscosity have been analyzed in the light of PFP theory and BAB method. A comparative study of the two approaches has been made. Excellent agreement between theoretical and experimental findings is achieved.     

Preparation,characterization and electrical conductivity of new heterobimetallic chalcogenates and their 1,10-phenanthroline adducts

New mixed metal chalcogenate coordination polymers, MPb(SCN)₂(SeCN)₂ [M = Co^II, Ni^II or Hg^II], Ag₂-Pb(SCN)₂(SeCN)₂, and the complex heterobimetallic salts, [M(phen)₃][Pb(SCN)₂(SeCN)₂][M = Co^II or Ni^II; phen = 1,10-phenanthroline] that have been prepared and characterized by elemental analyses, i.r. and u.v.–vis. spectra, and by powder XRD patterns. Their solid state electrical conductivities have been investigated, show _rt in the 10^–10–10^–6 S cm^–1 range, and semiconduct at 313–383 K with band gaps in the 0.28–0.91 eV range. [Co(phen)₃][Pb(SCN)₂(SeCN)₂], exhibits a remarkable increase, i.e. 10⁴ order of magnitude, in conductivity at higher temperature, which reflects a disordered metallic system where charge carriers have difficulty in crossing the non-conducting barrier at low temperature.     

A SPR and AFM study of the effect of surface heterogeneity on adsorption of proteins

The effect of chemical heterogeneity of surfaces on the adsorption of proteins was investigated using model surfaces prepared by self-assembly of omega-functionalized alkanethiols on gold substrates. Surface plasmon resonance was used to monitor the adsorption kinetics of bovine serum albumin (BSA) and the morphology of the adsorbed BSA was imaged with tapping mode atomic force microscopy. The experiments show that the morphology of the adsorbed protein layer was altered significantly only when the surface heterogeneity was distributed in a patchwise manner on a nanometer length scale, which is commensurate with the dimension of the protein. In contrast to linear flexible polymers where the initial adsorption rate remained unchanged upon introduction of the chemical heterogeneity, the initial rate for the globular protein changed from the value observed on homogeneous surfaces and was dependent on the heterogeneous distribution of the chemical sites.     

Assignment of 13C resonances of a nematic liquid crystal using off-magic angle spinning

A novel method for assigning the resonances in the 13C NMR spectrum of a static liquid crystalline sample in its nematic phase is proposed. The method is based on the fact that the carbon chemical shifts in the isotropic phase and in the oriented phase under static and off-magic angle spinning (OMAS) conditions are uniquely related by the tensorial property of the CSA tensor, requiring just one OMAS spectrum and the assignment in the isotropic phase. A computational procedure is proposed to take into account deviations arising out of non-ideal experimental conditions and the assignments are made by identifying the minimum in the differences in the frequencies between calculated and experimental line positions. Practical implementation of the method has also been demonstrated in the case of the liquid crystal N-(4-ethoxybenzylidene)-4-n-butylaniline.     

Selective quantification of lacosamide in human plasma using UPLC–MS/MS: Application to pharmacokinetic study in healthy subjects with different doses

A practical, sensitive, and robust UPLC–MS/MS method was developed and validated to quantify lacosamide in human plasma. A simple one-step protein precipitation was used to extract lacosamide and labeled lacosamide-13C, D3 as an internal standard (IS) from 150-μL plasma. The extracts were analyzed on an Eclipse Plus C18 column (50 × 2.1 mm, 1.8 μm) using 0.1% formic acid in water and methanol:acetonitrile (50:50, v/v) under gradient conditions. The extracts were quantified on LCMS-8040 using electrospray ionization source operated in positive ionization and multiple reaction monitoring modes. The method showed good linearity from 0.02 to 20 μg/mL, which was adequate to cover lacosamide concentration assayed in formulations with different strengths. The bioanalytical assay was fully validated as per current regulatory guidelines. The intra-batch and inter-batch precision values of lacosamide were less than 4.6%. Lacosamide was found to be stable at different storage conditions. The extraction recoveries and IS-normalized matrix factors for lacosamide ranged from 97.17 to 99.68% and from 0.973 to 1.012, respectively. The validated method was successfully applied to a pharmacokinetic study with three lacosamide formulations (50, 100, and 200 mg) in 36 healthy subjects. The assay reliability was determined by reanalysis of 81 subject samples.     

Validated LC–ESI–MS/MS method for the determination of tunicamycin in rat plasma: Application to a pharmacokinetic study

A liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) method has been developed and validated for the quantification of tunicamycin in rat plasma as per regulatory guideline. Chromatography of tunicamycin and the IS in the processed plasma samples was achieved on an X‐Terra phenyl column using a binary gradient (mobile phase A, acetonitrile and mobile phase B, 5 mm ammonium formate) elution at a flow rate of 0.6 ml/min. LC–MS/MS was operated under the multiple reaction monitoring mode using the electrospray ionization technique in positive ion mode and the transitions of m/z 817.18 → 596.10, 831.43 → 610.10, 845.29 → 624.10, 859.23 → 638.10 and 309.24 → 163.20 were used to quantitate homologs A–D and the IS, respectively. The total chromatographic run time was 4.5 min. The correlation coefficient (r²) was >0.99 for all homologs with accuracy 90.7–107.4% and precision 0.74–15.1%. The recovery of homologs was 78.6–90.2%. No carryover was observed and the matrix effect was minimal. Tunicamycin four homologs were found to be stable on the bench‐top for 6 h, for up to three freeze–thaw cycles, in the injector for 24 h and for 1 month at ?80 ° C. The applicability of the validated method has been demonstrated in a rat pharmacokinetic study.     

Diphenyltin(IV) dithiocarbamate macrocyclic scaffolds as potent apoptosis inducers for human cancer HEP 3B and IMR 32 cells: synthesis,spectral characterization,density functional theory study and in vitro cytotoxicity

Binuclear diphenyltin(IV) dithiocabamate macrocyclic complexes [(Ph₂Sn^IV)₂‐μ²‐bis{(κ²S,S‐S₂CN(R)CH₂CONHC₆H₄)₂O}] (R = ⁱPr ( 1 ), ^sBu ( 2 ), ⁿBu ( 3 ), Cy ( 4 ), 2‐furfuryl ( 5 ) or benzyl ( 6 )) were synthesized through a self‐assembly process involving novel diamino precursors 4,4′‐bis(2‐(alkylamino)acetamido)diphenyl ethers ( L¹ , L² , L³ , L⁴ , L⁵ , L⁶ ), CS₂ and Ph₂SnCl₂. These were characterized using microanalysis and relevant spectroscopic methods. The geometry of all compounds was optimized using the density functional theory method. In vitro cytotoxic activity was evaluated against HEP 3B (hepatoma) and IMR 32 (neuroblastoma) using the MTT assay. Notably, complexes 1 , 2 , 3 , 4 , 5 , 6 were found to be extremely active against both cell lines and cytotoxicity data confirmed their 16‐fold better potency compared to cisplatin, a well‐known antineoplastic drug. Flow cytometric analysis of annexin V–propidium iodide‐stained cells demonstrated the ability of L⁵ , 4 and 6 to induce apoptosis in HEP 3B and IMR 32 cells, required for major therapeutic implication in cancer therapy. The extraordinary potency of binuclear complex 4 can be correlated with higher LUMO energy together with the greatest value of residual charge on the Sn(IV) centre among the compounds under investigation. Copyright © 2015 John Wiley & Sons, Ltd.     

Langmuir-Blodgett film based on MEH-PPV for cholesterol biosensor

Cholesterol oxidase (ChOx) has been immobilized onto conducting poly[2-methoxy,5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV)/stearic acid (SA) Langmuir-Blodgett film transferred onto octadecanethiol (ODT) modified gold plate. The ChOx/MEH-PPV/SA LB film bioelectrode exhibits has been characterized by FT-IR, contact angle, and atomic force microscopy. The response of the ChOx/MEH-PPV/SA LB film bioelectrode carried out using differential pulse voltammetry (DPV) studies reveal linearity from 1.29 to 12.91 mM of cholesterol concentration and response time as 30 s. This ChOx/MEH-PPV/SA bioelectrode exhibits values of correlation coefficient as 0.9939, standard deviation as 0.0029 μA and limit of detection as 1.66 mM. UV-visible spectrophotometer studies reveal that 5.2 × 10⁻³ U of ChOx are actively working per cm² area of ChOx/MEH-PPV/SA LB film bioelectrode and this bioelectrode is thermally stable upto 55 °C with reusability of about 60 times.     

Short synthesis of octosyl nucleosides

[reaction: see text] Commercial 1,2:5,6-di-O-isopropylidene-alpha-d-allofuranose was converted to a protected bicyclic octosyl acid thioglycoside donor by a 10-step sequence that features an intramolecular ester enolate alkylation. Glycosylation of N-benzoyladenine and methyl uridine-5-carboxylate followed by deprotection gave the respective nucleosides "octosyl adenine" and octosyl acid A.     

Two dimensional electrophoretic analysis of human tears: collection method in dry eye syndrome

Tear proteomics, by 2-DE, can give a fingerprint of the protein profile, which is well suited in clinical proteomics for biomarker identification and in diagnostics. The mode of tear collection can influence the representation of the proteins in the tear and therefore it is important to use the appropriate method. In this study, capillary and Schirmer mode of tear collection was done in the healthy controls and the Schirmer method was validated in dry eye syndrome conditions. 2-D PAGE of normal and dry eye tear was performed using pH 3-10 linear IPG strips followed by 13% SDS-PAGE. The spot intensity was analyzed by the PD quest software. The two methods were compared using Bland-Altman statistical tool. The 2-D map of capillary and Schirmer tear showed 147 ± 8 spots and 145 ± 7 spots respectively. Both the collection methods were in agreement with each other and were comparable. Dry eye tear protein showed differential expression of proteins as observed in 25-35 kDa region. One of the significantly reduced protein was identified as proline-rich 4 protein. Schirmer method of tear collection is reliable in patients with dry eye, which can display the differential protein expression and help in biomarker identification.