Spectrofluorimetric Determination of Fluvoxamine in Dosage Forms and Plasma Via Derivatization with 4-Chloro-7-Nitrobenzo-2-Oxa-1,3-Diazole

A highly sensitive and simple spectrofluorimetric method has been developed and validated for the determination of the antidepressant fluvoxamine (FXM) in its dosage forms and plasma. The method was based on nucleophilic substitution reaction of FXM with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole in an alkaline medium (pH 8) to form a highly fluorescent derivative that was measured at 535 nm after excitation at 470 nm. The factors affecting the reaction was carefully studied and optimized. The kinetics of the reaction was investigated, and the reaction mechanism was presented. Under the optimized conditions, linear relationship with good correlation coefficient (0.9995) was found between the fluorescence intensity and FXM concentration in the range of 65–800 ng ml⁻¹. The limits of detection and quantitation for the method were 21 and 64 ng ml⁻¹, respectively. The precision of the method was satisfactory; the values of relative standard deviations did not exceed 2.17%. The proposed method was successfully applied to the determination of FXM in its pharmaceutical tablets with good accuracy; the recovery values were 97.8–101.4 ± 1.08–2.75%. The results obtained by the proposed method were comparable with those obtained by the official method. The high sensitivity of the method allowed its successful application to the analysis of FXM in spiked human plasma. The proposed method is superior to the previously reported spectrofluorimetric method for determination of FXM in terms of its simplicity. The proposed method is practical and valuable for its routine application in quality control and clinical laboratories for analysis of FXM.     

Link Homologies and the Refined Topological Vertex

We establish a direct map between refined topological vertex and sl(N) homological invariants of the of Hopf link, which include Khovanov-Rozansky homology as a special case. This relation provides an exact answer for homological invariants of the Hopf link, whose components are colored by arbitrary representations of sl(N). At present, the mathematical formulation of such homological invariants is available only for the fundamental representation (the Khovanov-Rozansky theory) and the relation with the refined topological vertex should be useful for categorizing quantum group invariants associated with other representations (R ₁, R ₂). Our result is a first direct verification of a series of conjectures which identifies link homologies with the Hilbert space of BPS states in the presence of branes, where the physical interpretation of gradings is in terms of charges of the branes ending on Lagrangian branes.     

Ultrasonic monitoring of malolactic fermentation in red wines

The progress of malolactic fermentation in red wines has been monitored by using ultrasonic techniques. The evolution of ultrasonic velocity of a tone burst 1 MHz longitudinal wave was measured, analyzed and compared to those parameters of oenological interest obtained simultaneously by analytical methods. Semi-industrial tanks were used during measurements pretending to be in real industrial conditions. Results showed that the ultrasonic velocity mainly changes as a result of the conversion by lactic acid bacteria of malic acid into lactic acid and CO₂. Overall, the present study has demonstrated the potential of the ultrasonic technique in monitoring the malolactic fermentation process.     

An investigation of motion correction algorithms for pediatric spinal cord DTI in healthy subjects and patients with spinal cord injury

Patient and physiological motion can cause artifacts in DTI of the spinal cord which can impact image quality and diffusion indices. The purpose of this investigation was to determine a reliable motion correction method for pediatric spinal cord DTI and show effects of motion correction on DTI parameters in healthy subjects and patients with spinal cord injury. Ten healthy subjects and ten subjects with spinal cord injury were scanned using a 3 T scanner. Images were acquired with an inner field-of-view DTI sequence covering cervical spine levels C1 to C7. Images were corrected for motion using two types of transformation (rigid and affine) and three cost functions. Corrected images and transformations were examined qualitatively and quantitatively using in-house developed code. Fractional anisotropy (FA) and mean diffusivity (MD) indices were calculated and tested for statistical significance pre- and post- motion correction. Images corrected using rigid methods showed improvements in image quality, while affine methods frequently showed residual distortions in corrected images. Blinded evaluation of pre and post correction images showed significant improvement in cord homogeneity and edge conspicuity in corrected images (p < 0.0001). The average FA changes were statistically significant (p < 0.0001) in the spinal cord injury group, while healthy subjects showed less FA change and were not significant. In both healthy subjects and subjects with spinal cord injury, quantitative and qualitative analysis showed the rigid scaled-least-squares registration technique to be the most reliable and effective in improving image quality.     

金属圆柱腔体中使用非均一背景增强微波断层成像

针对基于圆柱金属腔体的微波断层成像系统,提出了一种利用非均一背景增强系统获取目标信息能力的方法.该方法通过在腔体内放置已知物体构成非均一背景,这样不但能利用背景的先验信息,而且可以增加等效辐射源对目标进行探测.首先,利用矩量法计算圆柱金属腔体内非均一背景的格林函数和离散积分算子,并对离散积分算子进行奇异值谱和条件数分析,在理论上证明该方法的可行性;然后,利用基于有限元的对比源逆成像法对均一背景、有耗非均一背景和无耗非均一背景三种情况进行仿真研究;最后对仿真结果进行了误差分析和比较.仿真结果表明,该方法可以提高反演收敛速度和结果准确度,有耗非均一背景略优于无耗非均一背景.该方法可以在不改变硬件系统和算法的情况下得到更准确的反演结果,可应用于医学成像与工业无损探测.     

A Suitable Active Control for Suppression the Vibrations of a Cantilever Beam

In our consideration, a comparison between four different types of controllers for suppression the vibrations of the cantilever beam excited by an external force is carried out. Those four types are the linear velocity feedback control, the cubic velocity feedback control, the non-linear saturation controller (NSC) and the positive position feedback (PPF) controller. The suitable type is the PPF controller for suppression the vibrations of the cantilever beam. The approximate solution obtained up to the first approximation by using the multiple scale method. The PPF controller effectiveness is studied on the system. We used frequency-response equations to investigate the stability of a cantilever beam. We notified that, there is a good agreement between the analytical solution and the numerical solution.     

Bioguided isolation of pentacyclic triterpenes from the leaves of Alstonia scholaris (Linn.) R. Br. growing in Egypt

Ethanolic and aqueous extracts of the leaves and flowers of Alstonia scholaris were evaluated for their antioxidant activity by investigating their effect on blood glutathione levels in alloxan-induced diabetic rats. The ethanolic extract of the leaves was the most active; therefore, its cytotoxicity against HepG2 cells was also tested. Promising GI?? values of 1.96, 4.34 and 4.65?μg?mL?1 were observed for the extract, its chloroform and ethyl acetate fractions, respectively. The chloroform active subfraction I (GI???=?2.97?μg?mL?1) yielded betulin (1), betulinic acid (2) and ursolic acid (3) upon purification. Compounds 1-3 were identified using spectroscopic techniques and by comparison with reported data. GLC of unsaponifiable and saponifiable fractions of the hexane extract revealed β-sitosterol (7.37%) and n-tetracosane (54.4%) to be the major sterol and hydrocarbon components, respectively. Linoleic acid (48.89%) was the predominant fatty acid.     

Electrocortical and Biochemical Evaluation of Antidepressant Efficacy of Formulated Nanocurcumin

Applied Biochemistry and Biotechnology - The present study aims to evaluate the antidepressant efficacy of curcumin nanoparticles on rat model of depression induced by reserpine. Rats were divided...     

Set-theoretic constructions of nonshrinking open covers

A family {M_α|α?A} is a shrinking of a cover {O_α|α?A} of a topological space if {M_α|α?A} also covers and M_α?O_α for all α?A.?⁺⁺ implies that there is a normal space such that every increasing open cover of it has a clopen shrinking but there is an open cover having no closed shrinking.? implies that there is a P-space (i.e. a space having a normal product with every metric space), which has an increasing open cover having no closed shrinking. This space is used in [17] to show that any space which has a normal product with every P-space is metrizable.