Spectrophotometric and LC methods have been developed and validated for the analysis of alendronate sodium in tablet dosage forms. Methods were based on reaction of the primary amino group of alendronate with ninhydrin reagent in methanolic solution of sodium bicarbonate. The condensed product exhibited UV absorption maximum at 569 nm whereas neither the reagents nor the analyte had any UV absorption. A Box-Behnken statistical design was employed to study the effect of independent variables, ninhydrin (X1), NaHCO3 (X2) and drug concentration (X3) on dependent variable, absorption via spectrophotometer. From the point prediction tool of design software, it was observed that ninhydrin (0.26%) and NaHCO3 (0.048 mol L?1) produced maximum absorption. These optimized parameters were then selected for method validation. The methods obeyed Beer’s law over a selected concentration range with good correlation co-efficient (>0.99). The limit of detection and limit of quantification were 4.5 and 13.75 μg mL?1 by spectroscopy, and 87 and 263 ng mL?1 by LC, respectively. Accuracy, precision and % recovery were satisfactory for the proposed method. The method was highly feasible and reproducible for determination of alendronate sodium in bulk powder and pharmaceutical dosage form. 相似文献
Theoretical K-shell photoionization and K X-ray fluorescence (K XRF) cross sections have been fitted empirically in polynomials of photon energy E and atomic number Z. This has been used to develop a computer code KCSPIF to generate K-shell photo-ionization and K XRF cross-sections for any element in the range 5≤Z≤95 and for photon energies, above K-edge–1500 keV, when only the atomic number and photon energy are supplied as the input. 相似文献
The problem of the effect of dust particles on the thermal convection in micropolar ferromagnetic fluid saturating a porous medium subject to a transverse uniform magnetic field has been investigated theoretically. Linear stability analysis and normal mode analysis methods are used to find an exact solution for a flat micropolar ferromagnetic fluid layer contained between two free boundaries. In case of stationary convection, the effect of various parameters like medium permeability, dust particles, non-buoyancy magnetization, coupling parameter, spin-diffusion parameter and micropolar heat conduction parameter are analyzed. For sufficiently large values of magnetic parameter M1, the critical magnetic thermal Rayleigh number for the onset of instability is determined numerically and results are depicted graphically. It is also observed that the critical magnetic thermal Rayleigh number is reduced solely because the heat capacity of clean fluid is supplemented by that of the dust particles. The principle of exchange of stabilities is found to hold true for the micropolar ferromagnetic fluid saturating a porous medium heated from below in the absence of micropolar viscous effect, microinertia and dust particles. 相似文献
The present study tested whether subjects respond to unanticipated short perturbations in voice loudness feedback with compensatory responses in voice amplitude. The role of stimulus magnitude (+/- 1,3 vs 6 dB SPL), stimulus direction (up vs down), and the ongoing voice amplitude level (normal vs soft) were compared across compensations. Subjects responded to perturbations in voice loudness feedback with a compensatory change in voice amplitude 76% of the time. Mean latency of amplitude compensation was 157 ms. Mean response magnitudes were smallest for 1-dB stimulus perturbations (0.75 dB) and greatest for 6-dB conditions (0.98 dB). However, expressed as gain, responses for 1-dB perturbations were largest and almost approached 1.0. Response magnitudes were larger for the soft voice amplitude condition compared to the normal voice amplitude condition. A mathematical model of the audio-vocal system captured the main features of the compensations. Previous research has demonstrated that subjects can respond to an unanticipated perturbation in voice pitch feedback with an automatic compensatory response in voice fundamental frequency. Data from the present study suggest that voice loudness feedback can be used in a similar manner to monitor and stabilize voice amplitude around a desired loudness level. 相似文献
In this note, a sufficient condition for summability of Fourier series has been obtained which in conjunction with the author's Tauberian theorem [M.L. Mittal, A Tauberian theorem on strong Nörlund summability, J. Indian Math. Soc. 44 (1980) 369-377] on strong Nörlund summability gives a sufficient condition for summability [C,1,2] of a Fourier series. This generalizes results due to Prasad [G. Prasad, On strong Nörlund summability of Fourier series, Univ. Roorkee Res. J. 9 (1966-1967) 1-10] and Varshney [O.P. Varshney, Note on H2 summability of Fourier series, Boll. Un. Mat. Ital. 16 (1961) 383-385]. 相似文献
Unlike previously reported Zn and Se levels were found to be the same in the hair of mentally retarded children and controls. Non-essential toxic Ag concentration was low whereas that of Hg, Au and Sc rather high in mentally retarded children. 相似文献
Let {Xi, i?0} be a sequence of independent identically distributed random variables with finite absolute third moment. Then Darling and Erdös have shown that for -∞<t<∞ where and . The result is extended to dependent sequences but assuming that {Xi} is a standard stationary Gaussian sequence with covariance function {ri}. When {Xi} is moderately dependent (e.g. when we get where Ha is a constant. In the strongly dependent case (e.g. when we get for-∞<t<∞. 相似文献
Zusammenfassung Mit Hilfe der pH- und konduktometrischen Titrationen wurde die Stöchiometrie der Verbindungen untersucht, die bei der Reaktion von Uranylnitrat mit Alkali-Ortho-, Pyro- und Metaarseniten entstehen. Der Verlauf der Titrationskurven zeigt klar die Bildung der Verbindungen 3 UO2O · As2O3, 2 UO2O · As2O3 und UO2O · As2O3 in den pH-Bereichen 7,0–9,9 bzw. 6,0–7,5 bzw. 5,0–6,8. Der Anteil von Uranyl in den Alkaliarseniten wächst mit wachsender Konzentration von Na2O. Die Bildung der Uranylarsenite ist also eine Funktion der H+-Ionenkonzentration. Wir fanden, daß die Ausfällung dieser Verbindungen fast quantitativ ist.
The stoichiometry of the compounds formed by the interaction of uranyl nitrate and different alkali arsenites (ortho-, pyro-, and meta-) have been investigated by means of pH and conductometric titrations. The breaks and inflections in titration curves provide cogent evidence for the formation of 3 UO2O · As2O3, 2 UO2O · As2O3 and UO2O · As2O3 in pH ranges 7.0–9.9, 6.0–7.5 and 5.0–6.8 respectively. The proportion of uranyl increases with the increase in the concentration of Na2O molecules in alkali arsenites. The formation of uranyl arsenites is thus a function of H+ ion concentration. The precipitation of these compounds has been found to be almost quantitative.