Biosorption of copper(II) by nonliving lichen biomass of Cladonia rangiformis hoffm

Biosorption of heavy metals can be an effective process for the removal of heavy metal ions from aqueous solutions. In this study, the adsorption properties of lichen biomass of Cladonia rangiformis hoffm. for copper(II) were investigated by using batch adsorption techniques. The effects of initial metal ion concentration, initial pH, biosorbent concentration, stirring speed and contact time on biosorption efficiency were studied. In the experiments the optimum pH value was found out 5.0 which was the native pH value of solution. The experimental adsorption data were fitted to the Langmuir adsorption model. The highest metal uptake was calculated from Langmuir isotherm and found to be 7.6923 mg Cu(II)/g inactivated lichen at 15 degrees C. The results indicated that the biomass of C. rangiformis is a suitable biosorbent for removing Cu(II) from aqueous solutions.     

COMPARATIVE STUDY OF DISPATCHING RULES IN A REAL-LIFE JOB SHOP ENVIRONMENT

In this paper, we compare the performance of dispatching rules in a real-life job shop environment and provide guidance for schedulers to determine effective dispatching rules for this type of systems. We consider a total of 20 dispatching rules, that range from some previously developed rules to some recently developed sophisticated rules such as process time plus work in next queue plus negative slack (PT + WINQ + SL), multi factor rule, and bottleneck dynamics. The performance measures examined are average weighted tardiness and proportion of tardy jobs. Discrete event simulation model based on ARENA is developed to implement the rules. Results from this study are given in detail.     

Progression of excess embryos to the blastocyst stage predicts pregnancy and implantation rates after intracytoplasmic sperm injection

In the spherical cells of Escherichia coli rodA mutants, division is initiated at a single point, from which a furrow extends progressively around the cell. Using "giant" rodA ftsA cells, we confirmed that each new division furrow is initiated at the midpoint of the previous division plane and runs perpendicular to it.     

Testing of Drug Release from Bioadhesive Vaginal Tablets

To establish en in vitro test method that can predict the drug release and dissolution behaviour of vaginal bioadhesive controlled release tablets, a system was developed and its appropriateness to the in situ conditions was examined. For this purpose, the dissolution rates of vaginal bioadhesive tablets were measured by three different methods. These were, USP dissolution apparatus two and a new vaginal dissolution tester (NVDT) which was developed by us with some modification of the vaginal tablet desentegration apparatus of BP 1988 and, testing in cow vaginas in situ. Four different bioadhesive tablet formulations were used being composed of the drug and the anionic polymer, polyacrylic acid (PAA) and the nonionic polymers, hydroxypropylmethyl cellulose (HPMC) and ethyIcellulose (EC). The release profiles of the in vitro and in situ methods were investigated and evaluated kinetically.

It was found that NVDT could be used to investigate the drug release from vaginal tablets.     

The effects of various ratios of sunflower oil and surfactant on household type cake quality

The aim of this study was to determine the effects of sunflower oil (0, 5, 10, 15%) and surfactant (acetic and lactic acid esters of mono and diglycerides; 0, 0.25, 0.5, 0.75, 1%) on the quality of the wheat flour based household type cake. The variable ingredients were used as alone or in combinations in cake manufacture; therefore 20 different batter formulations were formed. Quality characteristics of cake samples (volume, symmetry, uniformity, shrinkage, weight loss, crumb–grain structure, crumb firmness) were investigated. Both components had a significant (P?<?0.05) impact on cake quality. In trial conditions, it was determined that the effect of surfactant on cake quality was greater than the oil. In cake batter, using up to a certain level (0.5%) surfactant was improved the cake volume and porosity. When the surfactant was used at 0.75 and 1% levels, these cake properties were deteriorated. The softness of the cakes have been measured as maximum when surfactant was used alone in increasing order from 0 to 1%. Sunflower oil improved the cake quality up to a limited extent. This improvement generally occurred at 5% level. Usage of oil with higher levels declined cake properties significantly. In combination formula, it was determined that using surfactant made using more oil in the batter formula possible. Careful attention should be paid to the appropriate level of use of oil and surfactant in cake production. Otherwise, significant declines occurred in cake quality. It was concluded that high-quality household-type cakes can be made if both ingredients were combined the use of 5–10% oil and 0.75–1% surfactant.     

Discordance of sialography and scintigraphy in unilateral chronic sialadenitis

A Tc-99m pertechnetate salivary gland scintigraphy, digital subtraction sialography (DSS) and cytological findings of a 48-year-old female who received I-131 therapy for the treatment of follicular carcinoma of thyroid are presented. Post radioiodine therapy sialoscintigraphy showed increased blood flow and uptake with decreased secretion in the left parotid gland suggesting acute inflammation. In contrast, DSS and fine needle aspiration biopsy (FNAB) findings were consistent with chronic sialoadenitis. Follow-up scintigraphy one month later showed normal blood flow and decreased uptake and confirmed the diagnosis of chronic sialoadenitis. In right of this case, we conclude that since management of sialoadenitis depends on the stage of inflammation scintigraphic findings should be interpreted together with radiology and FNAB findings if necessary. When chronic sialoadenitis is followed by acute exacerbations, diagnosis based exclusively on sialoscintigraphic findings may result in inadequate patient management.     

Conduction mechanism of an infrared emitting diode: Impedance spectroscopy and current-voltage analysis

The bias dependent complex impedance spectra of a conventional GaAs based infrared emitting diode have been studied in the temperature range 150–300 K. It is found that for bias voltages lower than 0.7 V, the device behaves like a pure capacitor. However for V _dc ≥ 0.7 V, an equivalent circuit model composed of a parallel resistor (R _p ) and capacitor (C _p ) network connected with a series resistance (R _s ) can be used to describe the individual impedance contributions from interfacial and bulk regions of the diode. Fitting of experimental data to the proposed ac model reveal that the value of parallel device capacitance C _p increases with temperature whereas the parallel resistance R _p component decreases. The tendency of parallel resistance and parallel capacitance as a function of temperature is expected that thermally activated current transport mechanism dominates in the forward bias, which coincides with the analysing results of the dark forward current-voltage (I–V) characteristics. The temperature dependent I–V variations suggest that recombination in the depletion region has a paramount role.     

Testing of drug release from bioadhesive vaginal tablets

To establish an in vitro test method that can predict the drug release and dissolution behaviour of vaginal bioadhesive controlled release tablets, a system was developed and its appropriateness to the in situ conditions was examined. For this purpose, the dissolution rates of vaginal bioadhesive tablets were measured by three different methods. These were, USF dissolution tester apparatus two and a new vaginal dissolution tester (NVDT) which was developed by us with some modification of the vaginal tablet desentegration apparatus of BP 1988 and, testing in cow vaginas in situ. Four different bioadhesive tablet formulations were used being composed of the drug and the anionic polymer, polyacrylic acid (PAA) and the nonionic polymers, hydroxypropylmethyl cellulose (HPMC) and ethycellulose (EC). The release profiles of the in vitro and in situ methods were ivestigated and evaluated kinetically     

Arbitrary precision computation of the set of stabilising gains for time-delay LTI systems

A new method is proposed to calculate the set of proportional controllers stabilising a given linear time-invariant system with a fixed time-delay. The method is based on the utilisation of Padé approximations for the time-delay, Lam's studies on the convergence of Padé approximations and a generalisation of the Nyquist theorem applicable to quasi-polynomials. The method allows determination of the closeness of the resulting set to the exact set of stabilising gains by tracing the uncertainty introduced by the Padé approximation. As a result, it is possible to approximate the resulting set arbitrarily close to the exact stabilising set.     

Kinetic and thermodynamic studies of the biosorption of Cr(VI) by Pinus sylvestris Linn

Biosorption equilibrium, kinetics and thermodynamics of chromium(VI) ions onto cone biomass were studied in a batch system with respect to temperature and initial metal ion concentration. The biosorption efficiency of chromium ions to the cone biomass decreased as the initial concentration of metal ions was increased. But cone biomass of Pinus sylvestris Linn. exhibited the highest Cr(VI) uptake capacity at 45 degrees C. The biosorption efficiency increased from 67% to 84% with an increase in temperature from 25 to 45 degrees C at an initial Cr(VI) concentration of 300 mg/L. The Langmuir isotherm model was applied to experimental equilibrium data of Cr(VI) biosorption depending on temperature. According to Langmuir isotherm, the monolayer saturation capacity (Q(max)) is 238.10 mg/g. The pseudo-first-order and pseudo-second-order kinetic models were applied to test the experimental data for initial Cr(VI). The pseudo-second-order kinetic model provided the best correlation of the used experimental data compared to the pseudo-first-order kinetic model. The activation energy of biosorption (E(a)) was determined as 41.74 kJ/mol using the Arrhenius equation. Using the thermodynamic equilibrium coefficients obtained at different temperatures, the thermodynamic constants of biosorption (DeltaG(0), DeltaH(0) and DeltaS(0)) were also evaluated.