Electrochemical degradation of amaranth aqueous solution on ACF

The degradation of Amaranth, a kind of azo dye, has been studied under galvanostatic model with activated carbon fiber (ACF) electrode in aqueous solution with electrochemical method. The ACF was used as anode and cathode, respectively for the decolorization process. The onset oxidation potential and reduction potential for Amaranth on ACF were respectively ascertained at 0.6 and -0.4 V. During the range of -1.1 to 0.50 mA cm(-2), the decolorization was clarified into three processes as electroreduction, adsorption and electrooxidation. There were little contributions to the color and COD removals for the process of adsorption. The color removal can be up to 99% when the current density was 0.50 mA cm(-2). The maximum COD removal was 52% for the process of electrooxidation. Hundred percent color removal was obtained when the current density of -1.0 mA cm(-2) was applied. The maximum COD removal was 62% for the electroreduction. The COD removal results from the adsorption of products for the decolorization process of electrooxidation or electroreduction.     

Nasal architecture: form and flow

Current approaches to model nasal airflow are reviewed in this study, and new findings presented. These new results make use of improvements to computational and experimental techniques and resources, which now allow key dynamical features to be investigated, and offer rational procedures to relate variations in anatomical form. Specifically, both replica and simplified airways of a single subject were investigated and compared with the replica airways of two other individuals with overtly differing geometries. Procedures to characterize and compare complex nasal airway geometry are first outlined. It is then shown that coupled computational and experimental studies, capable of obtaining highly resolved data, reveal internal flow structures in both intrinsically steady and unsteady situations. The results presented demonstrate that the intimate relation between nasal form and flow can be explored in greater detail than hitherto possible. By outlining means to compare complex airway geometries and demonstrating the effects of rational geometric simplification on the flow structure, this work offers a fresh approach to studies of how natural conduits guide and control flow. The concepts and tools address issues that are thus generic to flow studies in other physiological systems.     

Semiconductor-mediated photocatalysed degradation of two selected azo dye derivatives, amaranth and bismarck brown in aqueous suspension

Semiconductor-mediated photocatalysed degradation of two selected azo dye derivatives such as amaranth (1) and bismarck brown (2) has been investigated in aqueous suspension by monitoring the change in substrate concentration employing UV spectroscopic analysis technique as a function of irradiation time. The degradation was studied under different conditions such as types of TiO(2), pH, substrate concentration, catalyst concentration, and in the presence of electron acceptors such as hydrogen peroxide (H(2)O(2)), potassium bromate (KBrO(3)) and ammonium persulphate (NH(4))(2)S(2)O(8) besides air. The degradation rates were found to be strongly influenced by all the above parameters. The photocatalyst Degussa P25 showed comparatively highest photocatalytic activity. The dye derivative, bismarck brown (2) was found to degrade faster than amaranth dye (1).     

Photo-catalytic degradation of toxic dye amaranth on TiO2/UV in aqueous suspensions

The photo-catalytic degradation of an azo dye − Amaranth (AM) - has been investigated in TiO₂/UV aqueous suspensions. The results obtained from the experiments during H₂O₂/TiO₂ addition show that the highest decolorization rate is provided by the combination of (UV + TiO₂ + H₂O₂). The decolorization efficiencies were 17%, 26%, 38% and 64% in the runs UV, UV + H₂O₂, UV + TiO₂ and (UV + TiO₂ + H₂O₂) after approximately 100 min illumination periods, respectively. The observed dye degradation rates followed pseudo-first order kinetics with respect to the substrate concentration under the experimental conditions used. Different experimental conditions, such as temperature, pH and presence of electron acceptor were investigated. The temperature effect was investigated at the range of 293-313 K and it was observed that decolorization rate increased by the increase in temperature. Chemical oxygen demand and dye absorbance of the photodegraded dye solution substantially decreased. Effect of pH was also investigated and it was observed that the lower the pH the higher the degradation. In addition, an enhancement in the photodegradation rate was observed by the addition of hydrogen peroxide as an electron acceptor. The adsorption trends of Amaranth at various initial concentrations followed the Langmuir isotherm trend. This work adds to the global discussion on the role of the advanced oxidation processes in water treatment.     

纳米复合1.4μm光放大材料的荧光和吸收谱

纳米级掺稀土非氧化物团簇复合在氧化硅玻璃中，可以结合非氧化物玻璃和氧化物玻璃在光放大和化学，热力学，力学等方面各自的优点，提供可以应用于实用化1.3μm，宽带1.5μm和新发展的1.4μm光放大的新材料，在一种复合材料中，峰值位于1315nm的荧光峰及线型被证实与用来进行复合的掺稀土氟镓锆玻璃中的峰完全一致，而在复合材料中其荧光寿命较长，以Pr^3 和Nd^3 作为活性离子的复合材料的吸收谱线宽比Pr^3 和Nd^3 掺杂的ZBLAN的相应吸收谱线宽展宽最多达到10nm，复合材料的光谱性质有利于器件增益并放宽对泵浦光源的要求。     

Gas absorption and outgassing of metals

The solution of the diffusion equation is taken as a foundation of the theory of gas-metal interaction in high vacuum. The boundary conditions are formulated from the analysis of the gas balance equations on a metal surface and in a gas volume. The boundary conditions are generally non-linear but in some important cases linearization is permissible. In this way it is possible to obtain analytical expressions for the instantaneous gas flow on electron- and photon-induced desorption, low temperature thermal desorption and gettering at a constant pressure. By means of these formulae one can generalize the experimental data of various authors and calculate the kinetics of such processes as the outgassing of an electron collector, the gas desorption by synchrotron radiation in a vacuum chamber of electron or positron colliding-beam storage-rings, the degassing of an ultra-high vacuum system, the gas sorption by barium and titanium, etc.     

太阳能溴化锂吸收式制冷系统溶液降膜吸收流动分析

溴化锂降膜式吸收器能在较小液流量和较小温差下获得较高的热流密度和传热传质系数,尤其是当液膜沿着水平管外作降膜流动时,传热传质效果更佳。为此建立溴化锂降膜吸收器溶液吸收过程流动的物理模型,通过对模型假设简化,对其进行数值求解,从而进行流动分析。与实验结果分析相结合,使得对吸收式制冷系统的分析更加全面。     

Nasal Absorption of the Calcium Antagonist Nicardipine in Rats and Rhesus Monkeys

Nicardipine hydrochloride, a highly potent calcium entry channel blocker was administered intranasally to rats and rhesus monkeys. The Intranasal absorption of nicardipine in rats was studied with aqueous vehicles containing 0.1 M citrate buffer pH 3.5, 0.01 M acetate/propylene glycol (90:10 W/W) pH = 5.0, and a similar acetate/propylene glycol system containing sodium taurocholate. Peak plasma levels were found to occur 30 minutes after an Intranasal dose of 1.0 mg/kg, and the fraction absorbed using each of the vehicles described above was determined to be 0.85, 0.54, and 0.82 that of an equivalent Intravenous dose. These Initial screening studies were extended Into a monkey model system, with a similar group of formulations. The results obtained in the monkey were qualitatively similar to the data generated in the rat model with regard to rapid attainment of peak plasma levels and subsequent elimination from the plasma. The major difference between the two animal models studied was the significantly lower systemic availability observed in the monkey.     

Nasal Absorption of the Calcium Antagonist Nicardipine in Rats and Rhesus Monkeys

Abstract

Nicardipine hydrochloride, a highly potent calcium entry channel blocker was administered intranasally to rats and rhesus monkeys. The Intranasal absorption of nicardipine in rats was studied with aqueous vehicles containing 0.1 M citrate buffer pH 3.5, 0.01 M acetate/propylene glycol (90:10 W/W) pH = 5.0, and a similar acetate/propylene glycol system containing sodium taurocholate. Peak plasma levels were found to occur 30 minutes after an Intranasal dose of 1.0 mg/kg, and the fraction absorbed using each of the vehicles described above was determined to be 0.85, 0.54, and 0.82 that of an equivalent Intravenous dose. These Initial screening studies were extended Into a monkey model system, with a similar group of formulations. The results obtained in the monkey were qualitatively similar to the data generated in the rat model with regard to rapid attainment of peak plasma levels and subsequent elimination from the plasma. The major difference between the two animal models studied was the significantly lower systemic availability observed in the monkey.     

Development of a Cyclodextrin-Based Nasal Delivery System for Lorazepam

A new drug delivery system containing hydroxypropyl-β-cyclodextrin (HP-β-CD) and a mucoadhesive polymer was developed with the aim to overcome the limitations connected with the nasal application of drugs with low water solubility. Lorazepam, free or as cyclodextrin inclusion complex, was loaded into mucoadhesive microparticles by spray drying, using hydroxypropylmethyl cellulose (HPMC), carbomer, and HPMC/carbomer interpolymer complex (IPC) as mucoadhesive components. Differential scanning calorimetry (DSC) indicated the presence of drug crystalline areas in microparticles loaded with free lorazepam, whereas in those loaded with HP-β-CD inclusion complex, the drug was amorphous. Zeta potential measurement revealed that the polymer was the main component on the surface of the microparticles. The swelling rate and mucoadhesive properties of the microparticles were determined by the polymer type used in formulation. IPC- and carbomer-based microparticles showed superior swelling rate and mucoadhesion compared with the HPMC-based microparticles (p < .05). Drug loading into the polymer matrix decreased the swelling rate as well as the mucoadhesive properties of microparticles (p < .05), whereas the presence of HP-β-CD in the matrix did not induce any additional reduction of those parameters (p > .05). The in vitro dissolution studies demonstrated that the microparticles containing the lorazepam inclusion complex displayed 1.8–2.5 times faster drug release compared with those containing free lorazepam. The change in the drug release rate could be connected with improved drug solubility inside the polymer matrix due to inclusion complex formation, as well as to the reduction in crystallinity following complexation, as confirmed by DSC studies.     

Pharmacodynamic Comparison of a Nasal Formulation of Verapamil and Intravenous and Oral Dosage Forms

The nasal route has been shown to be effective for the administration of numerous drugs in order to improve drug bioavailability. A nasal gel of verapamil hydrochloride was formulated and evaluated pharmacodynamically in humans, using electrocardiographic results, with comparison to oral and IV routes. Seven volunteers were involved in the study and the pharmacodynamic parameters were evaluated statistically. Experimental nasal gel showed similar pharmacodynamic results with the intravenous route, which is a hint to the reduction in verapamilinduced first-pass metabolism. However, oral route of administration showed a tendency of less efficacy. No reasonable effect of verapamil could be obtained with the placebo group.     

Characterization of Dose Delivery and Spray Pattern of a Metered-Dose Flunisolide Nasal Spray

Flunisolide is a synthetic fluorinated corticosteroid with significant ant -inflammatory and anti-allergic activities. Flunisolide nasal solution (Nasalide®) is delivered by a unique pump-activated, non-propellant, metered-dose device. A previous paper (1) reported droplet size characterization of the nasal spray by a cascade impactor. This report describes the remaining physical characterizations, namely dose delivery and spray pattern, of this metered-dose delivery system as well as the suitability of the system for a therapeutic corticosteroid nasal solution.

Actuation of flunisolide nasal spray units by 10 subjects over time demonstrated good constancy of dose delivery for up to 24 days of use. The average dose delivery was 0.737 ± 0.040 gm/day (grand mean ± s.d.).

Actuation of similar units by 17 subjects over time showed good constancy of spray pattern, which was defined as the long and short diameters of the impaction pattern of the spray on a TLC plate, for the entire lifetime of the unit.     

Characterization of Dose Delivery and Spray Pattern of a Metered-Dose Flunisolide Nasal Spray

Abstract

Flunisolide is a synthetic fluorinated corticosteroid with significant ant -inflammatory and anti-allergic activities. Flunisolide nasal solution (Nasalide®) is delivered by a unique pump-activated, non-propellant, metered-dose device. A previous paper (1) reported droplet size characterization of the nasal spray by a cascade impactor. This report describes the remaining physical characterizations, namely dose delivery and spray pattern, of this metered-dose delivery system as well as the suitability of the system for a therapeutic corticosteroid nasal solution.

Actuation of flunisolide nasal spray units by 10 subjects over time demonstrated good constancy of dose delivery for up to 24 days of use. The average dose delivery was 0.737 ± 0.040 gm/day (grand mean ± s.d.).

Actuation of similar units by 17 subjects over time showed good constancy of spray pattern, which was defined as the long and short diameters of the impaction pattern of the spray on a TLC plate, for the entire lifetime of the unit.     

Development and In Vitro Characterization of Chitosan-based Microspheres for Nasal Delivery of Promethazine

ABSTRACT

Conventional and composed promethazine-loaded microspheres were prepared by spray drying of chitosan solution systems and double water-in-oil-in-water (W/O/W) emulsion systems, respectively. Double emulsions were prepared in two different feed concentrations, with chitosan dissolved in both water phases, and ethylcellulose dissolved in oil phase. Swelling and bioadhesive properties of the microspheres depended on the chitosan content, type and the feed concentration of spray-dried system. Results obtained suggested that better ethylcellulose microcapsules with promethazine in the chitosan matrix were formed when less concentrated emulsion systems were spray-dried. Thus, in case of such a system, with ethylcellulose/chitosan weight ratio of 1:2, prolonged promethazine release was obtained.     

Emission and absorption spectroscopy of magnetic materials

In recent years, optical methods have been accepted as a useful means for studying the magnetic properties in solids. In this paper it will be shown, from an introductory point of view, what kind of information optical studies can provide. The most numerous investigations have been performed with insulating materials. The observed phenomena can be divided into four types: first those where spectra can be described by a simple molecular field picture; second those where one incorporates small quantities of magnetic ions into a diamagnetic host and studies the spectra of various neighbour configurations; third those where one deals with the simultaneous excitation of states in the electronic system (excitons) and the spin system (magnons) which gives rise to the so-called magnon sidebands in absorption and emission spectra; and fourth those which deal with the exchange of energy between various magnetic sublattices by the magnetic interactions. Much less information is available on magnetic semiconductors. Yet here a very striking and perhaps technologically important effect has been observed, namely a considerable red shift of the absorption edge in going through the magnetic transition temperature, e.g., in EuO and EuS. In metals, so far only a few experiments have been performed, and only those on Ni and MnAg are mentioned here. In addition, the question of short-range correlations, which can be observed via optical spectra will be discussed. Finally, recent reviews in this field will be compiled to facilitate a deeper understanding.