A multicommuted flow-system for spectrophotometric determination of tannin exploiting the Cu(I)/BCA complex formation

A flow system exploiting the multicommutation approach is proposed for spectrophotometric determination of tannin in beverages. The procedure is based on the reduction of Cu(II) in the presence of 4,4`-dicarboxy-2,2`-biquinoline, yielding a complex with maximum absorption at 558 nm. Calibration graph was linear (r=0.999) for tannic acid concentrations up to 5.00 mu mol L-1. The detection limit and coefficient of variation were estimated as 10 nmol L-1 (99.7% confidence level) and 1% (1.78 mu mol L-1 tannic acid, n=10), respectively. The sampling rate was 50 determinations per hour. The proposed procedure is more sensitive and selective than the official Folin-Denis method, also minimizing drastically waste generation. Recoveries within 91.8 and 115% were estimated for total tannin determination in tea and wine samples. (C) 2007 Elsevier B.V. All rights reserved.

A method for Ca, Fe, Ga, Na, Si and Zn determination in alumina by inductively coupled plasma optical emission spectrometry after aluminum precipitation

In this present work a method for the determination of Ca, Fe, Ga, Na, Si and Zn in alumina (Al(2)O(3)) by inductively coupled plasma optical emission spectrometry (ICP OES) with axial viewing is presented. Preliminary studies revealed intense aluminum spectral interference over the majority of elements and reaction between aluminum and quartz to form aluminosilicate, reducing drastically the lifetime of the torch. To overcome these problems alumina samples (250 mg) were dissolved with 5 mL HCl + 1.5 mLH(2)SO(4) + 1.5 mL H(2)O in a microwave oven. After complete dissolution the volume was completed to 20 mL and aluminum was precipitated as Al(OH)(3) with NH(3) (by bubbling NH(3) into the solution up to a pH similar to 8, for 10 min). The use of internal standards (Fe/Be, Ga/Dy, Zn/In and Na/Sc) was essential to obtain precise and accurate results. The reliability of the proposed method was checked by analysis of alumina certified reference material (Alumina Reduction Grade-699, NIST). The found concentrations (0.037%w(-1) CaO, 0.013% w w(-1) Fe(2)O(3), 0.012%w w(-1)Ga(2)O(3), 0.49% w w(-1) Na(2)O, 0.014% w w(-1) SiO(2) and 0.013% w w(-1) ZnO) presented no statistical differences compared to the certified values at a 95% confidence level. (C) 2011 Elsevier B.V. All rights reserved.

Anodic stripping voltammetric determination of copper(II) using a functionalized carbon nanotubes paste electrode modified with crosslinked chitosan

The development and application of a functionalized carbon nanotubes paste electrode (CNPE) modified with crosslinked chitosan for determination of Cu(II) in industrial wastewater, natural water and human urine samples by linear scan anodic stripping voltammetry (LSASV) are described. Different electrodes were constructed using chitosan and chitosan crosslinked with glutaraldehyde (CTS-GA) and epichlorohydrin (CTS-ECH). The best voltammetric response for Cu(II) was obtained with a paste composition of 65% (m/m) of functionalized carbon nanotubes, 15% (m/m) of CTS-ECH, and 20% (m/m) of mineral oil using a solution of 0.05 mol L(-1) KNO(3) with pH adjusted to 2.25 with HNO(3), an accumulation potential of 0.3V vs. Ag/AgCl (3.0 mol L(-1) KCl) for 300 s and a scan rate of 100 mV s(-1). Under these optimal experimental conditions, the voltammetric response was linearly dependent on the Cu(II) concentration in the range from 7.90 x 10(-8) to 1.60 x 10(-5) mol L(-1) with a detection limit of 1.00 x 10(-8) mol L(-1). The samples analyses were evaluated using the proposed sensor and a good recovery of Cu(II) was obtained with results in the range from 98.0% to 104%. The analysis of industrial wastewater, natural water and human urine samples obtained using the proposed CNPE modified with CTS-ECH electrode and those obtained using a comparative method are in agreement at the 95% confidence level. (C) 2009 Elsevier B. V. All rights reserved.

THE POTENTIALITIES OF USING A GRAPHITE-SILICONE RUBBER COMPOSITE ELECTRODE IN THE DETERMINATION OF PROPRANOLOL

A graphite silicone-rubber composite electrode (GSR) was used for the determination of propranolol in drug formulation. Cyclic voltammetry (CV) at the GSR presented an irreversible oxidation peak at + 0.8V vs. SCE, in Britton Robinson (B-R) buffer pH 7.4. The quantitative determination was carried out using differential pulse voltammetry (DPV). Under optimized parameters a linear dynamic range from 5.0 to 80.6 mu mol L(-1) with a detection limit of 1.1 mu mol L(-1) was observed. A repeatability of 4.5 +/- 0.1 mu A (n = 10) peak current was found after 10 successive DPV voltammograms of propranolol in the same solution after surface renovations. Using the proposed electrode, propranolol was quantified in a pharmaceutical formulation with results that agreed within 95% confidence level (t-test) with those from an official method.

Determination of Minoxidil by Bleaching the Permanganate Carrier Solution in a Flow-Based Spectrophotometric System

The determination of minoxidil (MX) with potassium permanganate as a carrier in a flow injection method is described. The detection at 550nm was linear from 1.0x10-5 to 5.0x10-4mol L-1. The limit of detection (3 sigma/slope) was 8.92x10-6mol L-1, with an analytical frequency of 32h-1. The proposed method was applied to commercial samples, with recoveries from 104.7 to 106.4%. Comparison with the HPLC procedure reveled relative errors from 0.48 to 1.4%, and the results agreed within a 95% confidence level.

Simultaneous voltammetric determination of paracetamol and caffeine in pharmaceutical formulations using a boron-doped diamond electrode

A simple and highly selective electrochemical method was developed for the single or simultaneous determination of paracetamol (N-acetyl-p-aminophenol, acetaminophen) and caffeine (3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione) in aqueous media (acetate buffer, pH 4.5) on a boron-doped diamond (BDD) electrode using square wave voltammetry (SWV) or differential Pulse voltammetry (DPV). Using DPV with the cathodically pre-treated BDD electrode, a separation of about 550 mV between the peak oxidation potentials Of paracetamol and caffeine present in binary mixtures was obtained. The calibration curves for the simultaneous determination of paracetamol and caffeine showed an excellent linear response, ranging from 5.0 x 10(-7) mol L(-1) to 8.3 x 10(-7) mol L(-1) for both compounds. The detection limits for the simultaneous determination of paracetamol and caffeine were 4.9 x 10(-7) mol L-1 and 3.5 x 10(-8) mol L(-1), respectively. The proposed method Was Successfully applied in the simultaneous determination of paracetamol and caffeine in several pharmaceutical formulations (tablets), with results similar to those obtained using a high-performance liquid chromatography method (at 95% confidence level). (C) 2008 Elsevier BY. All rights reserved.

Loyalty to the profession? A study of Australian financial planners

The purpose of this paper is to examine the demographic variables of age and gender in conjunction with three independent variables: Internal versus external locus of control personality dimension, individualist versus collectivist personality dimension, and perceived environmental uncertainty and to relate same to the professional commitment (PC) of financial planners in Australia. A questionnaire was used to survey a sample of 312 financial planners nationally, with a 36% response rate and statistically significant results. At the 90% confidence level (p=0.10) respondents over the age of 35 demonstrated no difference between their levels of professional commitment than did those under the age of 35, while at the same level of confidence, females demonstrated a statistically significant higher level of PC than did their male counterparts. Respondents with an external locus of control displayed lower levels of PC (p=0.10) that those with an internal locus of control. These findings contribute to our understanding of the professional commitment of financial planners, and are important from a public policy perspective in an era of increasing attention to, and likely increased regulation of, the financial planning industry.

Organisational commitment of financial planners in Australia

The purpose of this paper is to determine whether the demographic variables of age, gender and length of service can be shown to be related to the organisational commitment (OC) of financial planners in Australia. The financial planners were surveyed using an instrument derived from established questionnaires. It was mailed nationally to 312 financial planners. A response rate of 36% was achieved, equating to 113 useable responses. The analyses revealed statistically significant results at the 90% confidence level (p=0.10), that respondents over the age of 35 demonstrated a significantly higher level of OC than did those under the age of 35, and at the same level of confidence, females demonstrated a statistically significant higher level of OC than did their male counterparts.

Such findings contribute to our understanding of the organisational commitment of Financial Planners, and have implications for employers in terms of hiring and retention of employees. The analyses are also important from a public policy perspective in an era of increasing attention given to, and likely increased regulation of, the financial planning industry.

An examination of the organisational commitment of financial planners

This paper sets out to determine whether the demographic variables of age, gender, length of service can be shown to be related to the organisational commitment (OC) of financial planners in Australia. The financial planners were surveyed using an instrument derived from established questionnaires. It was mailed nationally to 312 financial planners. A response rate of 36% was achieved, equating to 113 useable responses. The analyses revealed statistically significant results at the 95% confidence level (p=0.05), that female respondents demonstrated a statistically significant higher level of OC than did their male counterparts.Such findings contribute to our understanding of the organisational commitment of Financial Planners, and have implications for employers in terms of hiring and retention of employees. The analyses are also important from a public policy perspective in an era of increasing attention given to, and likely increased regulation of, the financial planning industry.

Professional commitment of financial planners in Australia: an examination

The purpose of this paper is to examine the demographic variables of age and gender in conjunction with three independent variables: Internal versus external locus of control personality dimension, individualist versus collectivist personality dimension, and perceived environmental uncertainty and to relate same to the professional commitment (PC) of financial planners in Australia. A questionnaire was used to survey a sample of 312 financial planners nationally, with a 36% response rate and statistically significant results. At the 95% confidence level (p=0.05) respondents over the age of 35 demonstrated no difference between their levels of professional commitment than did those under the age of 35, while at the same level of confidence, females demonstrated no statistically significant difference in their level of PC than did their male counterparts. Respondents with an external locus of control displayed lower levels of PC (p=0.05), than those with an internal locus of control but these were not statistically significant. These findings contribute to our understanding of the professional commitment of financial planners, and are important from a public policy perspective in an era of increasing attention to, and likely increased regulation of, the financial planning industry.

Financial planners in Australia : an examination of loyalty

The purpose of this paper is to determine whether the demographic variables of age, gender and length of service, and the levels of the three independent variables of internal versus external locus of control personality dimension, individualist versus collectivist personality dimension, and perceived environmental uncertainty can be shown to be related to the organisational commitment (OC) and professional commitment (PC) of financial planners in Australia. The financial planners employed by one major Australian bank, during the period November to December, 2004 were surveyed using an instrument derived from established questionnaires. It was mailed nationally to 312 financial planners. A response rate of 36% was achieved, equating to 113 useable responses. The analyses revealed no statistically significant results at the 95% confidence level (p=0.05), that the level of OC and PC for respondents over the age of 35 differed from those under the age of 35. At the same level of confidence, females demonstrated a statistically significant higher level of OC than did their male counterparts, however there was no difference between their levels of PC. Financial planners employed for a period of over 3 years showed no difference in their levels of OC or PC than those employed for a period of less than 3 years (p=0.05). Respondents with an external locus of control displayed  statistically significant lower levels of OC than those with an internal locus of control, however there was no difference between these groups in their levels of PC (p=0.05). Such findings contribute to our understanding of the organisational and professional commitment of financial planners, and have implications for employers in terms of hiring and retention of employees. The analyses are also important from a public policy perspective in an era of increasing attention to, and likely increased regulation of, the financial planning industry.

Estimating process capability index Cpm using a bootstrap sequential sampling procedure

Construction of a confidence interval for process capability index CPM is often based on a normal approximation with fixed sample size. In this article, we describe a different approach in constructing a fixed-width confidence interval for process capability index CPM with a preassigned accuracy by using a combination of bootstrap and sequential sampling schemes. The optimal sample size required to achieve a preassigned confidence level is obtained using both two-stage and modified two-stage sequential procedures. The procedure developed is also validated using an extensive simulation study.

Prediction interval construction using interval type-2 fuzzy logic systems

This study proposes a novel non-parametric method for construction of prediction intervals (PIs) using interval type-2 Takagi-Sugeno-Kang fuzzy logic systems (IT2 TSK FLSs). The key idea in the proposed method is to treat the left and right end points of the type-reduced set as the lower and upper bounds of a PI. This allows us to construct PIs without making any special assumption about the data distribution. A new training algorithm is developed to satisfy conditions imposed by the associated confidence level on PIs. Proper adjustment of premise and consequent parameters of IT2 TSK FLSs is performed through the minimization of a PI-based objective function, rather than traditional error-based cost functions. This new cost function covers both validity and informativeness aspects of PIs. A metaheuristic method is applied for minimization of the non-linear non-differentiable cost function. Quantitative measures are applied for assessing the quality of PIs constructed using IT2 TSK FLSs. The demonstrated results for four benchmark case studies with homogenous and heterogeneous noise clearly show the proposed method is capable of generating high quality PIs useful for decision-making.

Uncertainty quantification for wind farm power generation

Accurate forecasting of wind farm power generation is essential for successful operation and management of wind farms and to minimize risks associated with their integration into energy systems. However, due to the inherent wind intermittency, wind power forecasts are highly prone to error and often far from being perfect. The purpose of this paper is to develop statistical methods for quantifying uncertainties associated with wind power generation forecasts. Prediction intervals (PIs) with a prescribed confidence level are constructed using the delta and bootstrap methods for neural network forecasts. The moving block bootstrap method is applied to preserve the correlation structure in wind power observations. The effectiveness and efficiency of these two methods for uncertainty quantification is examined using two month datasets taken from a wind farm in Australia. It is demonstrated that while all constructed PIs are theoretically valid, bootstrap PIs are more informative than delta PIs, and are therefore more useful for decision-making.

Towards automated detection of depression from brain structural magnetic resonance images

Introduction : Depression is a major issue worldwide and is seen as a significant health problem. Stigma and patient denial, clinical experience, time limitations, and reliability of psychometrics are barriers to the clinical diagnoses of depression. Thus, the establishment of an automated system that could detect such abnormalities would assist medical experts in their decision-making process. This paper reviews existing methods for the automated detection of depression from brain structural magnetic resonance images (sMRI).Methods : Relevant sources were identified from various databases and online sites using a combination of keywords and terms including depression, major depressive disorder, detection, classification, and MRI databases. Reference lists of chosen articles were further reviewed for associated publications.Results : The paper introduces a generic structure for representing and describing the methods developed for the detection of depression from sMRI of the brain. It consists of a number of components including acquisition and preprocessing, feature extraction, feature selection, and classification.Conclusion : Automated sMRI-based detection methods have the potential to provide an objective measure of depression, hence improving the confidence level in the diagnosis and prognosis of depression.