Investigations on Romashkino asphaltic bitumen. 3. Fractionation of asphaltenes using ion-exchange chromatography

The fractionation of asphaltenes originally separated¹ from Romashkino asphaltic bitumen has been achieved by means of stepwise anion- and cation-exchange chromatography through macroreticular resins. The fractionation procedure and yields of the fractions are given. A detailed structural analysis has been made of original asphaltenes and their acid- and base-free fraction using elemental and densimetric analyses, gel-permeation chromatography and proton magnetic resonance spectroscopy. Inverse gas-liquid chromatography has also been used to detect the chemical functionality of the asphaltene fractions. Results are presented to show the effect of ion-exchange resins treatment upon the composition of asphaltenes, noting that molecular weight as well as chemical structure changes appreciably.     

Gefitinib–cyclodextrin inclusion complexes: physico-chemical characterization and dissolution studies

Background: Gefitinib, an anticancer drug, has an extremely low aqueous solubility, and its oral absorption is limited by its dissolution rate. The solubility and dissolution of gefitinib can be improved by complexation with cyclodextrins (CDs). Methods: Phase solubility studies of gefitinib with hydroxypropyl βCD (HPβCD) and randomly methylated βCD (RMβCD) in n various aqueous systems was conducted to characterize the complexes in the liquid state. The inclusion complexes in the solid state were prepared by freeze-drying method and characterized by X-ray diffractometry (X-RD) and differential scanning calorimetry (DSC). Results: Gefitinib formed stable complexes with HPβCD and RMβCD in distilled water as indicated by the association rate constants (Ks) of 458.9 and 1096.2 M^?1 for HPβCD and RMβCD, respectively. The complexation of gefitinib with CDs in pH 4.5 acetate buffer indicated an A_N type of phase-solubility diagrams, whereas gefitinib and HPβCD in distilled water in the presence of polymers such as polyvinyl pyrrolidone K-30 (PVP) or hydroxypropyl methylcellulose E3 (HPMC) resulted in A_P-type phase-solubility diagrams. The solid-state amorphous complexes (as described by DSC and X-RD) showed substantial increases in the solubility and dissolution rate of gefitinib with both CDs. Further increases in the solubility and dissolution rate of the gefitinib-HPβCD freeze-dried complex were obtained by physically mixing the complex with PVP and HPMC. Conclusion: Gefitinib formed stable inclusion complexes with HPβCD and RMβCD, and the solubility and dissolution rate of the drug was significantly increased.     

Design and implementation of a CIM information system

Information integration is vital for keeping manufacturing operations competitive. A case study approach has been adopted to better understand the role of informatio in integrated manufacturing. Information is now considered a corporate asset. The creation, processing, movement and security of information is therefore as important as the products/services of an enterprise. The case studies have helped in identifying the requirements and issues involved in developing an information system and supporting software framework for a manufacturing enterprise. This paper deseribes a case study dealing with the integrated manufacture of optical fiber products. A phased development and implementation approach was adopted where a small, manageable slice of the system is considered for the case study followed by functional modeling (IDEFO) and data flow modeling (data flow diagrams). This identifies the pieces of information of interest. The information relationships are modeled using extended entity relationship (EER) diagrams which are then mapped to a relational model. The relational tables thus obtained were implemented on a commercial Database Management System (DBMS). The functional constraints and application interfaces were then built using Structured Query Languages (SQL) and commercial application interface tools. Subsequent sections describe the functional models, data flow diagrams (DFDs), EER diagrams, relational database design and user/application interfaces developed for the system. Implementation experiences and observations are discussed along with the applications of the implemented system. The case study has helped in developing a preliminary data model (i.e., a model about data by which a reasonable interpretation of the data can be obtained) for material handling (MH) functions.     

Brominated fatty acid distribution in tissues and fluids of rats fed brominated vegetable oils

Rats dosed orally for four days with 0.24 g/kg body weight per day of brominated olive oil (BOO) or brominated sesame oil (BSO) were found to accumulate dibromostearic (DBS) acid (from BOO) and DBS and tetrabromosteric (TBS) acids (from BSO) in the liver, heart and adipose tissue. The metabolites, dibromopalmitic, and dibromomyristic acids (from BOO and BSO), as well as their tetrabromo-analogues (from BSO) were found as determined by gas chromatography with halogen specific detection and confirmed by gas chromatography-mass spectrometry. Blood contained no DBS, TBS or metabolites. However, inorganic bromide was observed in both blood and urine while none was observed in the feces. The latter contained significant quantities of both DBS and TBS but showed the absence of the four brominated metabolites.     

Heuristic algorithm based on molecules optimizing their geometry in a crystal to solve the problem of integer factorization

Integer factorization is a vital number theoretic problem finding frequent use in public key cryptography, and other areas like Fourier transforms. There has been growing interest among researchers in innovative alternative approaches to solving the problem by modeling some optimizing natural or biological behaviour in a form of an algorithm that can be used to solve the problem provided the problem can be represented as an optimization task. In this paper, we present a new model based on computational chemistry behind how molecules interact among each other to minimize their surface energy potential in a typical crystal. While this phenomenon itself is a research problem, it interestingly provides a new way of solving other problems like integer factorization which can be represented in different forms of discrete optimization task. However, we must note that the present methods based on such models are not scalable to the real-world scenario, and we present a brief discussion on this issue.     

Solution processed low-voltage metal-oxide transistor by using TiO2/Li–Al2O3 stacked gate dielectric

Journal of Materials Science: Materials in Electronics - A solution processed top-contact bottom-gated SnO2 thin-film transistor (TFT) has been fabricated using a TiO2/Li–Al2O3 bilayer...     

Fast and Slow Release: Synthesis of Gelatin Casted-Film Based Drug Delivery System

Present effort intends to improve the performance of gelatin based casted-films for controlled delivery of hydrophobic drugs. To achieve this goal, Piperine (a model drug) was loaded into gelatin (type A) casted-films by solvent evaporation method. Glutaraldehyde was used as a cross-linker for the gelatin films to modulate the drug release behavior and to prolong the rate of degradation of the film. In-vitro degradation study under physiological conditions and thermal analysis through differential scanning calorimetry were performed to confirm stability of the gelatin casted-film matrix. Aim was to control the drug release from films by varying the cross-linking degree and the gelatin concentration. Optical microscope analysis was performed to study the surface topography of the sample. In order to understand the drug–polymer interaction in the film, attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) analysis was done. The in-vitro release study gave an overall idea of the role of cross-linkers, gelatin concentration, and effect of pH on the release profiles of Piperine. Results show that one can effectively use gelatin casted-film based drug delivery systems for a wide range of release requirements, i.e., from fast release to delayed release.     

Synthesis and characterization of CdS doped TiO2 nanocrystalline powder: A spectroscopic study

This report aimed to study the effect of CdS doping in TiO₂ on the phase transformation of TiO₂ from anatase to rutile using X-ray diffraction (XRD) and Raman spectroscopy. CdS-doped TiO₂ nanocomposites have been prepared and characterized using Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). We have observed that contrary to bare TiO₂, phase transformation of TiO₂ from anatase to rutile is hindered when doped with CdS at high temperature. Raman spectroscopy is found to be more sensitive for detection of the surface of TiO₂ as compared to XRD.