Showing papers by "Jadavpur University published in 1979"

Interaction of acridine orange monohydrochloride dye with sodiumdodecylsulfate, (SDS) cetyltrimethylammoniumbromide (CTAB) and p-tert-octylphenoxypolyoxy ethanol (Triton X 100) surfactants

Abstract: Results of spectrophotometric, conductometric and dialysis studies on the interaction of acridine orange monohydrochloride dye with sodiumdodecylsulfate (anionic), cetyltrimethylammoniumbromide (cationic) and Triton X 100 (nonionic) surfactants have been reported. The anionic surfactant, SDS has been observed to undergo both electrostatic and hydrophobic interactions with the dye cation. Aggregation of the dye molecules can be destroyed when the surfactant is in large excess, whereas, excess dye can check micellization of SD S. At a ratio of AO:SDS=1:7 and above, dye embedded mixed micelles are formed. These remain in a separate phase, probably as coacervates. At lower ratios than 1:7, aggregation of dye molecules is induced, which being complexed with SDS become stabilized as colloids. The colloid and the coacervate have been observed to be thermally stable, negatively charged materials that can be broken by salts, and cations of higher valency are more effective in this regard. An 1:3 = AO:SDS colloid has beeen found to be sufficiently large like the coacervates to pass through a membrane having cut off permeability for molecular weights 12,000 and above. All the above features of AO-SDS interaction have been observed to be absent for AO-CTAB and AO-TX 100 systems, Even hydrophobic interaction has played an insignificant role in these cases. Thus, the dye cation, the cationic and the nonionic surfactants have almost retained their self physicochemical identities in solution in the presence of each other. Electrostatic interaction is thus the primary requirement for acridine orange-surfactant (anionic) system; the hydrophobic effect is secondary and may become co-operative.

Hydrophobic interactions of DNA with long-chain amines.

Abstract: The binding ratio, Γa, for several long-chain amines to calf-thymus DNA was measured as function of the ligand concentration, C, using the equilibrium dialysis method. The different amines used in the binding experiments at constant temperature were dodecyl trimethyl ammonium bromide (DTAB), myristyl trimethyl ammonium bromide (MTAB), cetyl trimethyl ammonium bromide (CTAB), and cetyl pyridinium chloride (CPCL). The formation and dissociation of the saturated DNA–amine complex were reversible. The initial slope of the binding isotherm decreased sharply with the reduction of the electrostatic effect as a result of the increase of the ionic strength of the medium. A sharp inflexion region was noted in the binding isotherm where the ligands bound in significant numbers may undergo hydrophobic interactions with each other. Γa increased with C until a maximum value, Γam, was reached, beyond which binding slowly decreased with an increase of concentration. Both Γam and Γa increased significantly with the increase of the hydrocarbon chain length of a ligand. The free energy change ΔGm for each saturated DNA–amine complex was evaluated on the basis of a thermodynamic relation and the standard state for binding was defined. The average free energy change for the binding per CH2 group of the amine was found to be −1550 cal/mol. The difference between ΔGm for CTAB and CPCL was examined on the basis of the structural difference of their head groups. The binding isotherms for MTAB and CPCL were obtained from the binding data at 15, 30, and 45°C. The binding increased with increasing temperature. From the plot of ΔGm/T vs 1/T, the changes in enthalpy and entropy due to the binding were evaluated for MTAB and CPCL. The binding reactions in these two cases were driven primarily by the entropy change due to the hydrophobic interaction. Standard free energy changes ΔG0m for the unsaturated complexes were close to ΔGm for the saturated complexes. The binding isotherms also depended on the nature of the neutral salt of the medium. At a given salt concentration, the order of the binding of the inorganic salts was as follows: KCl > NaCl > LiCl > Na2SO4 > MgCl2. The effect of pH on binding was also examined. The importance of these results on the formation of the reconstituted and natural nucleohistone complexes is discussed.

Ultracentrifugation of salt‐soluble proteins in ten legume species

Abstract: The ultracentrifugation patterns of the total salt-soluble proteins in pea and northern bean showed four globulin fractions in flour proteins but only the 2S, 7S and 9S globulins were found in the isolates. Mung bean, lentil and lupin exhibited 2S, 7S and 11S globulins in flour and isolate proteins while chick-pea, field-pea, faba-bean and soya-bean proteins also contained the 15S fraction. Salt-soluble proteins from lima bean were unique in their composition of 5S, 7S and 15S fractions. Only pea bean and lentil failed to show high proportions of the 1-5S fraction in the flour proteins.

Physico‐chemical studies of model meat emulsion in relation to the preparation of stable sheep and goat meat sausage

Abstract: The capacity of water and salt-soluble proteins obtained from the meat of goat, sheep, chicken and pork to emulsify peanut oil was compared at different protein concentrations in an aqueous medium. At a given concentration, the maximum phase-volume ratio (om) of oil in the emulsion for water-soluble proteins was in the order: goatchicken sheeppork. For pure actomyosin, the order of om was the following: goatsheep porkchicken. The same order for the actomyosins was also verified by viscometric experiments. From gel electrophoretic analysis, the number and nature of the polypeptide chains of pure actomyosins prepared from various meat sources were found to be different from each other. At higher protein concentrations, om was observed to exceed 0.6 both in the presence of salt extracted proteins and meat slurries. Melted sheep and goat fat formed very unstable emulsions in the presence of their respective meat slurries. GLC experiments indicated that the poor dispersibility of the sheep and goat fat was due to the presence of excessive quantities of saturated fatty acids so that the melting point was too high. When sheep fat was mixed with 50% peanut oil, then mixed fat formed excellent emulsions with the sheep meat slurry and om was observed to exceed 0.7. Using model meat emulsions, sheep meat sausage was prepared and found to be acceptable by a taste panel.

Transfer free energies of some ions from water to dimethylsulfoxide-water and urea-water mixtures

Abstract: The standard free energies of transfer (ΔGto) of some electrolytes from water to aqueous mixtures of dimethylsulfoxide (DMSO) and of urea have been split into the contribution from individual ions by use of the reference electrolyte Ph4AsBPh4 (RE), where Ph=phenyl. For each of the solvents, ΔGto(Ph4AsBPh4) was determined from the solubility products of the salts KBPh4, Ph4AsPi, and KPi, where Pi=picrate ion. The observed ΔGto(i) values for the individual ions are strikingly different from the corresponding values obtained by the simultaneous extrapolation (SE) procedure reported earlier.

Triglyceride composition of chrysalis oil, an insect lipid

Abstract: Chrysalis oil, an insect fat obtained from the spent silk worm pupae, Bombyx mori, is a by-product of sericultural industry and represents a potential source of 1750 tons of linolenic-rich oil per annum for India. Fatty acid and triglyceride compositions of chrysalis oil have been determined by the combination of the techniques of lower temperature segregation, lipolysis, thin layer and gas liquid chromatography. Percentage contents of the component acids are: C14:0, 0.6; C16:0, 19.3; C18:0 3.9; C18:1, 17.7; C18:2, 9.8, and C18:3, 48.7. Major component triglycerides are, LLnLn, 5.2%; PLnO, 6.4%;OLnLn, 9.6%; LnLnLn, 10.5% and PLnLn, 14.0% (P, palmitic; O, oleic; L, linoleic and Ln, linolenic acids. On low temperature crystallization, Chrysalis oil yielded two fractions amounting together to 40% of the total with composition quite similar to that of linseed oil.

A new equal-valued grounded-capacitor resonator realization using current conveyor

Abstract: Using a second generation current conveyor (CC II), a new resonator network containing a resistance (R)-capacitance (C)-frequency dependent negative resistance (D) series configuration is proposed. The network is canonic and both the equal-valued capacitors are grounded. ω 0 and Q of the resonator have been shown to be practically insensitive to changes in active parameters.

Surface waves in a thermo piezoelectric medium of monoclinic symmetry

Abstract: Propagation of surface waves on the surface of a monoclinic piezoelectric crystal has been studied taking into account the coupling of temperature field, a situation which is considered to be quite realistic. Variation of the piezoelectric potential, particle displacement and temperature with the distance from the free surface have been investigated.

Floating ideal inductor with one d.v.c.c.s.

Abstract: A floating-ideal-inductor realisation scheme with one d.v.c.c.s., two amplifiers and a grounded capacitor is presented. It is also shown that, from this scheme, a grounded-capacitor/three-amplifier floating-ideal-inductor realisation scheme can be easily derived.

Insensitive grounded-capacitor simulation of grounded inductors using current conveyors

Abstract: Two new schemes for grounded-inductor simulation with single grounded capacitors using the second-generation current conveyors (c.c. II) are reported. The realised inductors L and their quality factors Q can be independently adjusted and hence are suitable for high-quality applications. L and Q are shown to be quite stable and are practically insensitive to the changes in the active c.c. II parameters.

New grounded-capacitor ideal differentiators

Abstract: A general scheme is presented in which a grounded-capacitor ideal integrator (GCII) function is reciprocated to realize a grounded-capacitor ideal differentiator (GCID) function and vice versa. Some new single-amplifier grounded-capacitor ideal differentiator structures are also reported.

Novel active-R ideal frequency-dependent negative-resistance simulation

Abstract: A novel structure for the simulation of an ideal frequency-dependent negative-resistance (FDNR) element based on the single-pole rolloff characteristics of the operational amplifier is reported. The structure uses only operational amplifiers and a resistor.

Iterative computation of transonic shock-free profile flow at zero incidence

Abstract: An approximate form of the transonic integral equation of Oswatitsch for steady inviscid flow past a thin symmetric profile at zero incidence has been studied iteratively. A direct iteration scheme has been presented, which converges to the same shock-free supercritical flow for four different starting solutions. Another square-root iteration scheme, which converges in subcritical flow, has been discussed. Also, the computational results delivered by the Schubert-Schleiff series [2] are presented briefly. Computational results show that, for a parabolic arc profile, shock-free supercritical flow exists for values of the reduced thickness ratio τ in the range 0.596<τ<0.64.

Penecontemporaneous dolomitization in the Precambrian Bhander Limestone, Rajasthan, India — A petrographic attestation

Abstract: Dolomitization in the Precambrian Bhander Limestones around Bhainsrorgarh, Rajasthan was largely penecontemporaneous with deposition in tidally influenced evaporating pans. Regardless of the circumstantial evidence relating to the environment, prelithification dolomitization is evident independently from intimate control of the depositional fabric on the process, swerving of calcite laminae around dolomite porphyrotopes, and streaming of mica flakes around dolospars. Penecontemporaneity of this dolomitization is inferred from its confinement within selected lamina/e or bed/s, leaving the adjacent laminae or beds completely unaffected, plastic deformation and occasional mechanical failure of seams of pallisade calcite crystals infilling shrinkage cracks, formation of thin dolomitized crusts at lamina-top surfaces and its downward gradation to primary calcmicrite by gradual depletion of dolomite concentration and erosion of such crusts prior to deposition of overlying sediments. In modern settings penecontemporaneous dolomite crystals are usually less than 5 micron size but in present case they are mostly much coarser. This coarsening presumably arises from epitaxial growth on initially micron-sized dolomites. There are, of course, partly overlapping phases in dolomitization. Epigenetic dolomitization operated in a subordinate scale and has sometimes been manifested as passive precipitation in voids.

Proton transfer complexing equilibrium in micellar solution

Abstract: Proton transfer complexing equilibrium in aqueous media between p-nitrosalicylic acid and ethylenediamine has been studied in presence of CTAB, SDS, TX-100 and PEG, where CTAB and SDS have been observed to enhance the reaction whereas, TX-100 and PEG have suppressed it. Salts like KCl and NaCl have got antagonistic effects on the activities of CTAB and SDS. The proton transfer phenomenon can help determining the cmc of the additives. The equilibrium constants of the process have been determined and the standard thermodynamic parameters, ΔH°, JG' andΔ S° have been derived. The process has shown ‘isothermodynamic’ linear enthalpy-entropy relationship.

Novel capacitor floatation scheme

Abstract: An earlier suggested ideal floating inductor realisation circuit is extended to a capacitor floatation scheme with the addition of only one operational amplifier. Appropriate comments regarding practical realisability of both floating capacitor and inductor are appended.

Integrable insensitive subaudio-frequency sine-wave generator using DVCVS/DVCCS

Abstract: A novel sine-wave oscillator using the differential voltage-controlled voltage/current source (DVCVS/DVCCS) with only two resistors and two grounded capacitors is proposed. The oscillator is tunable in the subaudio ranges by a grounded resistor in a practically insensitive manner.

A high-input impedance inverting/noninverting active gain block

Abstract: A two-amplifier two-resistor configuration is proposed which is suitable for applications as a general gain block of either inverting on noninverting types. The structure has high-input impedance and the gain can be adjusted by a grounded resistor.

Free energies of transfer of alkali metal halides in isodielectric acetonitrile and ethylene glycol mixtures at 25°C

Abstract: Standard free energies of transfer (ΔG t o ) of alkali metal chlorides MCl (M=Li, Na, K, Rb, Cs) and of potassium bromide and iodide from ethylene glycol to its isodielectric mixtures containing 20, 40, and 60 wt. % acetonitrile have been determined from emf measurements at 25°C. The standard potentials of the M/M+, the Ag−AgBr, and the Ag−AgI electrodes have been calculated using auxiliary emf measurements. All electrolytes were found to be increasingly destabilized in mixed solvents of increasing acetonitrile content; the relative order of cation destabilization is Li+>Na+>K+>Rb+>Cs+ and that of anion destabilization is Cl−>Br−>I−, both following (a) the order of increasing softness of ions and increasing interaction with the soft base, acetonitrile,and (b) the order of decreasing hydrogen-bonding propensity of ions and decreasing interactions with the hard base, ethylene glycol.

Studies on magnetic damping due to pinned domain wall motion (II)

Abstract: The action of a magnetic field on the motion of domain walls of a ferromagnetic material is studied. The critical field above which the domain walls leave their pinning centres and show hysteresis or amplitude dependent damping, is calculated from the theory of pinning of domain walls by dislocations. The theory elegantly explains the magnetomechanical damping. The peak damping as a function of temperature, deduced here, is capable of explaining the experimental observations of different workers for different ferromagnetic materials like Iron, Gadolinium, and Nickel. The problem is seen from dynamical consideration and is solved by a powerful operational method. Es wird die Wirkung eines Magnetfeldes auf die Bewegung von Domanenwanden in ferromagnetischen Materialien untersucht. Das kritische Feld, oberhalb dessen die Domanenwande ihre Anhaft-zentren verlassen und Hysterese oder amplitudenabhangige Dampfung zeigen, wird aus der Theorie des Anhaftens von Domanenwanden an Versetzungen berechnet. Die Theorie erklart in eleganter Weise die magnetomechanische Dampfung. Die Maximumdampfung als Funktion der Temperatur, die abgeleitet wird, ist in der Lage, die experimentellen Beobachtungen verschiedener Autoren an verschiedenen feerromagnetischen Materialien wie Eisen, Gadolinium und Nickel zu erklaren. Das Problem wird als dynamisch behandelt und mit einer leistungsfahigen Operatorenmethode gelost.

An extended deformable shell model for ionic crystals including quadrupolar deformation of the charge cloud

Abstract: It is well known that the dipolar and scalar deformation of the charge cloud around an ion in ionic crystals are quite significant in describing the different lattice mechanical properties Even after the inclusion of the above deformations systematic discrepancies between theory and experiment persist An attempt is made to incorporate the effect of the quadrupolar distortion of the charge cloud in the framework of the deformable shell model All the relevant equations and lattice sums are evaluated for the CsCl structure and a preliminary application of the complete model which takes into account simultaneously the scalar, the dipolar and the quadrupolar deformation considered for a CsCl structure crystal So far there is no estimate of the effect of the quadrupolar distortion on the different properties of a crystal belonging to CsCl structure The calculation indicates that the effect is quite considerable for certain properties and its inclusion improves the overall agreement with experiment Es ist gut bekannt, das eine skalare und Dipoldeformation der Ladungswolke um ein Ion in Ionenkristallen sich vollig verschieden bei der Beschreibung der verschiedenen gittermechanischen Eigenschaften verhalt Sogar nach der Einfuhrung der oben erwahnten Deformationen bleiben systematische Diskrepanzen zwischen Theorie und Experiment bestehen Es wird der Versuch gemacht, den Einflus der quadrupolaren Verzerrung der Ladungswolke in den Rahmen des deformierbaren Schalenmodells einzufugen Alle relevanten Gleichungen und Gittersummen werden fur die CsCl-Strukturen berechnet, und es wird eine vorlaufige Anwendung des vollstandigen Modells, das gleichzeitig die skalare, die Dipol- sowie die Quadrupoldeformation berucksichtigt, fur einen CsCl-Strukturkristall untersucht Bisher existiert noch keine Abschatzung des Einflusses der Quadrupolverzerrung auf die verschiedenen Eigenschaften eines Kristalls, der zur CsCl-Struktur gehort Die Rechnungen zeigen, das der Einflus ganz betrachtlich fur gewisse Eigenschaften ist und seine Einbeziehung die Gesamtubereinstimmung mit dem Experiment verbessert