Synthesis and antimicrobial evaluation of novel 3-(arylideneamino)-3a,8a-dihydroxy-1,3,3a,8a-tetrahydroindeno[1,2-d]imidazole-2,8-diones and their 2-thioxo analogues

The preparation of some novel 3-(arylideneamino)-3a,8a-dihydroxy-1,3,3a,8a-tetrahydroindeno[1,2-d]imidazole-2,8-diones 8(i–xiv) and 3-(arylideneamino)-3a,8a-dihydroxy-2-thioxo-1,3,3a,8a-tetrahydroindeno[1,2-d]imidazol-8(2H)-ones 9(i–xiv) have been reported through one-pot catalyst-free reaction of aldehydes, semicarbazide hydrochloride/thiosemicarbazide with ninhydrin. All the synthesized compounds have been screened for antimicrobial activity and some of them were observed to possess broad spectrum antibacterial potential as well as significant antagonistic potential against fungal pathogens.     

Effect of Additives on the Activity of Tannase from <Emphasis Type="Italic">Aspergillus awamori</Emphasis> MTCC9299

Tannase from Aspergillus awamori MTCC 9299 was purified using ammonium sulfate precipitation followed by ion-exchange chromatography. A purification fold of 19.5 with 13.5% yield was obtained. Temperature of 30 °C and pH of 5.5 were found optimum for tannase activity. The effects of metals and organic solvents on the activity of tannase were also studied. Metal ions Mg⁺², Mn⁺², Ca⁺², Na⁺, and K ⁺ stimulated the tannase activity, while Cu⁺², Fe⁺³, and Co⁺² acted as inhibitors of the enzyme. The addition of organic solvents like acetic acid, isoamylalcohol, chloroform, isopropyl alcohol, and ethanol completely inhibited the enzyme activity. However, butanol and benzene increased the enzyme activity.     

Response Surface Optimization of Medium Components for Naringinase Production from <Emphasis Type="Italic">Staphylococcus xylosus MAK2</Emphasis>

Response surface methodology was used to optimize the fermentation medium for enhancing naringinase production by Staphylococcus xylosus. The first step of this process involved the individual adjustment and optimization of various medium components at shake flask level. Sources of carbon (sucrose) and nitrogen (sodium nitrate), as well as an inducer (naringin) and pH levels were all found to be the important factors significantly affecting naringinase production. In the second step, a 22 full factorial central composite design was applied to determine the optimal levels of each of the significant variables. A second-order polynomial was derived by multiple regression analysis on the experimental data. Using this methodology, the optimum values for the critical components were obtained as follows: sucrose, 10.0%; sodium nitrate, 10.0%; pH 5.6; biomass concentration, 1.58%; and naringin, 0.50% (w/v), respectively. Under optimal conditions, the experimental naringinase production was 8.45 U/mL. The determination coefficients (R ²) were 0.9908 and 0.9950 for naringinase activity and biomass production, respectively, indicating an adequate degree of reliability in the model.     

Cell Disruption Optimization and Covalent Immobilization of β-D-Galactosidase from <Emphasis Type="Italic">Kluyveromyces marxianus</Emphasis> YW-1 for Lactose Hydrolysis in Milk

β-D-galactosidase (EC 3.2.1.23) from Kluyveromyces marxianus YW-1, an isolate from whey, has been studied in terms of cell disruption to liberate the useful enzyme. The enzyme produced in a bioreactor on a wheat bran medium has been successfully immobilized with a view to developing a commercially usable technology for lactose hydrolysis in the food industry. Three chemical and three physical methods of cell disruption were tested and a method of grinding with river sand was found to give highest enzyme activity (720 U). The enzyme was covalently immobilized on gelatin. Immobilized enzyme had optimum pH and temperature of 7.0 and 40 °C, respectively and was found to give 49% hydrolysis of lactose in milk after 4 h of incubation. The immobilized enzyme was used for eight hydrolysis batches without appreciable loss in activity. The retention of high catalytic activity compared with the losses experienced with several previously reported immobilized versions of the enzyme is significant. The method of immobilization is simple, effective, and can be used for the immobilization of other enzymes.     

Morphology of heavy ions irradiated mica

The samples of natural mica (muscovite and biotite) were irradiated with energetic heavy ions [¹³⁶Xe (11.56 MeV/n) and ¹⁹⁷Au (11.40 MeV/n)] from universal linear accelerator (UNILAC) GSI, Darmstadt, Germany. The simple track etch technique has been used to develop and analyze the morphology of induced heavy ions and natural alpha recoil tracks with the help of atomic force microscopy. Defective structure and lattice disorder have been observed in the environs of the etch pits in these layered crystalline materials. The distribution of defects produced along the tracks, geometrical analysis of tracks shapes and shallowness and their correlations with the structural arrangement of the materials have been discussed in the present investigation. Importance of different ion track geometries in micaceous minerals for the fabrication of nanoterrace material with different stacks having sharp edges with unique properties has been elaborated in the present paper.     

Application of classical transportation methods to find the fuzzy optimal solution of fuzzy transportation problems

To the best of our knowledge till now there is no method in the literature to find the exact fuzzy optimal solution of unbalanced fully fuzzy transportation problems. In this paper, the shortcomings and limitations of some of the existing methods for solving the problems are pointed out and to overcome these shortcomings and limitations, two new methods are proposed to find the exact fuzzy optimal solution of unbalanced fuzzy transportation problems by representing all the parameters as LR flat fuzzy numbers. To show the advantages of the proposed methods over existing methods, a fully fuzzy transportation problem which may not be solved by using any of the existing methods, is solved by using the proposed methods and by comparing the results, obtained by using the existing methods and proposed methods. It is shown that it is better to use proposed methods as compared to existing methods.     

Highly hydrated poly(allylamine)/silica magnetic resin

The creation of multifunctional nanomaterials by combining organic and inorganic components is a growing trend in nanoscience. The unique size-dependent properties of magnetic nanoparticles (MNPs) make them amenable to numerous applications such as carriers of expensive biological catalysts, in magnetically assisted chemical separation of heavy metals and radionuclides from contaminated water sources. The separation of minor actinides from high-level radionuclide waste requires a sorbent stable in acidic pH, with ease of surface functionalization, and a high capacity for binding the molecules of interest. For the described experiments, the MNPs with 50 nm average size were used (size distribution from 20 to 100 nm and an iron content of 80–90 w/w%). The MNPs that have been double coated with an initial silica coating for protection against iron solubilization and oxidation in nitric acid solution (pH 1) and a second silica/polymer composite coating incorporating partially imbedded poly(allylamine) (PA). The final product is magnetic, highly swelling, containing >95% water, with >0.5 mmol amines g^?1 available for functionalization. The amine groups of the magnetic resin were functionalized with the chelating molecules diethylenetriaminepentaacetic acid (DTPA) and N,N-dimethyl-3-oxa-glutaramic acid (DMOGA) for separation of minor actinides from used nuclear fuel.     

Rapidity distribution as a probe for elliptical flow at intermediate energies

The interplay between spectator and participant matter in heavy-ion collisions is investigated within the isospin-dependent quantum molecular dynamics (IQMD) model in terms of the rapidity distribution of light charged particles. The effect of different types and sizes of rapidity distributions is studied in elliptical flow. The elliptical-flow patterns show the important role of nearby spectator matter on the participant zone. This role is further explained on the basis of the passing time of the spectator and the expansion time of the participant zone. The transition from in-plane to out-of-plane emission is observed only when the mid-rapidity region is included into the rapidity bin. Otherwise no transition occurs. The transition energy is found to be highly sensitive to the size of the rapidity bin, while it is only weakly dependent on the type of the rapidity distribution. These theoretical findings are found to be in agreement with experimental results.     

Role of WO3 in structural and optical properties of WO3-Al2O3-PbO-B2O3 glasses

Glass samples of composition xAl₂O₃-20PbO-(80−x)B₂O₃ and xWO₃-xAl₂O₃-20PbO-(80−2x)B₂O₃ with x varying from 0% to 10% mole fraction are prepared by melt quench technique. The optical band gap decreases (from 3.21 to 2.37 eV) more for WO₃-Al₂O₃-PbO-B₂O₃ glasses with an addition of WO₃ content. The FTIR spectral studies have pointed out the conversion of structural units of BO₃ to BO₄ and WO₄ to WO₆ in these glasses. The increase in density from 4.51 to 5.80 g cm⁻³ for WO₃-Al₂O₃-PbO-B₂O₃ glasses is observed with an increase in WO₃ content. This is observed that the atomic structure changes more with the incorporation of WO₃. This is due to the formation of WO₆, WO₄ and BO₄ units.     

Influence of reactive gas and temperature on structural properties of magnetron sputtered CrSiN coatings

CrSiN coatings were deposited on stainless steel (Grade: SA304) and silicon Si(1 0 0) substrates, with varying argon-nitrogen gas proportions and deposition temperature, using reactive magnetron sputtering technique in the present work. The influence of sputtering (Ar) and reactive gas proportions (N₂) and temperature on the structural properties of the CrSiN coating was investigated. A small amount of silicon content (3.67 at.% Si) plays a crucial role in addition to the nitrogen content for the formation of different phases in the CrSiN coatings as observed in the present work. For example, the coating with comparatively low nitrogen content, 40% N₂, during deposition, formed a crystalline structure consisting of nano-crystalline CrN which is separated by an amorphous SiN phase, as evident from X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The formation of CrN(1 1 1) and Cr₂N(1 1 1) phases has occurred at 30% N₂ with 3.67% Si content, which transformed in to CrN(1 1 1) and CrN(2 0 0) with increase in N₂ content but with same Si content. The surface topography and morphology of the coatings were analyzed by atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM), respectively. A less columnar growth is observed in CrSiN coatings deposited at low argon content, Ar:N₂ (20:80), and with 3.67 at.% Si in the coatings. However, it becomes dense with increase in nitrogen content and temperature. The XRD analysis showed that the intensity of a dominating peak (1 1 1) is decreasing from (80:20) to (60:40) argon:nitrogen environment. With a further increase of nitrogen content, from (60:40), in the sputtering gas mixture, to (40:60) argon-nitrogen, there is a sudden increase in (1 1 1) peak and above (40:60), the peak reduction rate is very slow than the previous one. The (1 1 1) and (2 0 0) peak intensity variations are very limited due to high nitrogen content, above 50%, and considerable amount of Si atoms, 3.67 at.%, present in the CrN coatings.