Electrochemical detection of carbidopa using a ferrocene-modified carbon nanotube paste electrode

A chemically modified carbon paste electrode (MCPE) containing ferrocene (FC) and carbon nanotubes (CNT) was constructed. The electrochemical behavior and stability of the MCPE were investigated by cyclic voltammetry. The electrocatalytic activity of the MCPE was investigated and it showed good characteristics for the oxidation of carbidopa (CD) in phosphate buffer solution (PBS). A linear concentration range of 5 to 600 μM CD, with a detection limit of 3.6±0.17 μM CD, was obtained. The diffusion coefficient of CD and the transfer coefficient () were also determined. The MCPE showed good reproducibility, remarkable long-term stability and especially good surface renewability by simple mechanical polishing. The results showed that this electrode could be used as an electrochemical sensor for the determination of CD in real samples, such as urine samples

Importance-performance analysis of port’s services quality form perspective of containerized liner shipping

One of the important issues in port services is to evaluate the performance of the services. Without evaluating port services and their related components, these services cannot be considered desirable and its quality cannot be enhanced. However, the evaluation and the quality assurance of port services should be accomplished based on a scientific framework and a coherent framework to have desirable results. The importance-performance analysis model is an appropriate framework where each component is evaluated in terms of two dimensions of importance and performance. This study performs performance-importance analysis of ports’ services quality form perspective of containerized liner shipping in the Imam Khomeini port. In this exploratory study, 150 shipping lines experts are chosen, randomly in 2012. The study identifies 28 components of quality in port services and shipping lines’ experts are requested to evaluate these components in terms of two dimensions of importance and performance. Results reveal that there is a gap between the importance and performance of all port services components except three components of 6, 19 and 24. In addition, the results indicate that Importance-Performance Analysis (IPA) model is capable of evaluating and assuring quality in port services and can precisely identify the strengths and weaknesses of the seaport system and provide guidance for strategy formulation for quality improvement

Incremental Principal Component Analysis Based Outliers Detection Methods for Spatiotemporal Data Streams

In this paper, we address outliers in spatiotemporal data streams obtained from sensors placed across geographically distributed locations. Outliers may appear in such sensor data due to various reasons such as instrumental error and environmental change. Real-time detection of these outliers is essential to prevent propagation of errors in subsequent analyses and results. Incremental Principal Component Analysis (IPCA) is one possible approach for detecting outliers in such type of spatiotemporal data streams. IPCA has been widely used in many real-time applications such as credit card fraud detection, pattern recognition, and image analysis. However, the suitability of applying IPCA for outlier detection in spatiotemporal data streams is unknown and needs to be investigated. To fill this research gap, this paper contributes by presenting two new IPCA-based outlier detection methods and performing a comparative analysis with the existing IPCA-based outlier detection methods to assess their suitability for spatiotemporal sensor data streams

Nanomaterials in biomedicine, drug delivery and pharmaceutical analysis

After the introduction of nanotechnology as a new science, there were tremendous changes in its application. Nanomaterials rapidly penetrate a diverse area of biomedicine and pharmaceutical research, including drug development, drug delivery, tissue engineering and medicinal chemistry. Its versatile use helps in alleviating complex difficulties faced with drug administration and absorption, controlled release, targeted delivery and cellular uptake. Due to their distinctive physico-chemical properties and ability to form various solid-state formulations, they find increased use in the preparation of new drug formulations, imaging techniques and particularly in medicinal chemistry as catalysts for the sensitive determination of drugs and other biologically active compounds. The role of nanomaterials as catalysts in the preparation of substances with pharmacological properties, the preparation of sensors, or the degradation and removal of medicinal compounds polluting the environment is undeniable

Moisture dependent physical and mechanical properties of Syrjan region wild pistachio nut

The wild pistachio (Pistacia Atlantica Mutika) exists in 2.4 million hectares of Iranian forest. In this way the pistachio of Syrjan was chosen as the case of study. The objective of this study was to determine physical and mechanical properties of wild pistachio nut of Syrjan rejoin as a function of moisture content. The physical properties including thousand unit  mass, length, width, height, arithmetic mean diameter, geometric mean diameter, surface area, true density, bulk density, porosity, repose angle (emptying and filling) and coefficient of friction were determined at  four different levels of moisture content. The nut was compressed along the length and thickness at 0.045, 0.069, 0.089 and 0.188 (d.b.) moisture contents to determine required force, deformation and energy per volume (toughness) at rupture point. The nut average length, width, thickness were 7.31, 6.17 and 4.90 mm, respectively at moisture content of 5.5 (%, w.b.). The greatest true density was 1081 kg/cm3. With increase moisture from 4.84 to 13.65 (%, w.b.) the bulk density of nut decreased from 658.21 to 636.68 kg/m3, porosity decreased from 37.52 to 32.86%, the emptying angle of repose increased from 32.04 to 34.6 degree, and the filling angle of repose increased from 29.95 to 31.59 degree. The greatest friction coefficient of the nut was obtained on galvanized iron surface and the minimum value on aluminum surface at all moisture content levels. At all levels of moisture content the rupture force, deformation at rupture point and toughness of the nut were the minimum values along the nut thickness (Z-axis). The minimum values of the rupture force, deformation and toughness were 175.16 N; 1.03 mm; and 0.49 mJ/mm3, respectively. Keywords: Wild pistachio, nut, moisture content, Syrjan, physical properties, mechanical propertie

An Artificial Neural Network for Movement Pattern Analysis to Estimate Blood Alcohol Content Level

Impairments in gait occur after alcohol consumption, and, if detected in real-time, could guide the delivery of “just-in-time” injury prevention interventions. We aimed to identify the salient features of gait that could be used for estimating blood alcohol content (BAC) level in a typical drinking environment. We recruited 10 young adults with a history of heavy drinking to test our research app. During four consecutive Fridays and Saturdays, every hour from 8 p.m. to 12 a.m., they were prompted to use the app to report alcohol consumption and complete a 5-step straight-line walking task, during which 3-axis acceleration and angular velocity data was sampled at a frequency of 100 Hz. BAC for each subject was calculated. From sensor signals, 24 features were calculated using a sliding window technique, including energy, mean, and standard deviation. Using an artificial neural network (ANN), we performed regression analysis to define a model determining association between gait features and BACs. Part (70%) of the data was then used as a training dataset, and the results tested and validated using the rest of the samples. We evaluated different training algorithms for the neural network and the result showed that a Bayesian regularization neural network (BRNN) was the most efficient and accurate. Analyses support the use of the tandem gait task paired with our approach to reliably estimate BAC based on gait features. Results from this work could be useful in designing effective prevention interventions to reduce risky behaviors during periods of alcohol consumption

Frequency Domain Electroretinography in Retinitis Pigmentosa versus Normal Eyes

Purpose: To compare electroretinogram (ERG) characteristics in patients with retinitis pigmentosa (RP) and normal subjects using frequency domain analysis. Methods: Five basic ERG recordings were performed in normal subjects and patients with a clinical diagnosis of RP according to the ISCEV (International Society of Clinical Electrophysiology of Vision) protocol. Frequency domain analysis was performed by MATLAB software. Different frequency domain parameters were compared between the study groups. Results: Peak frequency (Fmod) of flicker and oscillatory responses in RP patients showed significant (P<0.0001) high pass response as compared to normal controls. Peak frequency (Fmod) of the other responses was not significantly different between the two groups. Conclusion: In addition to conventional ERG using time domain methods, frequency domain analysis may be useful for diagnosis of RP. Oscillatory and flicker responses may be analyzed in frequency domain. Fast Fourier transform may reveal two distinct high pass responses (shift to higher frequencies) in Fmod. Time and frequency domain analyses may be performed simultaneously with many modern ERG machines and may therefore be recommended in RP patients