Development and validation of colorimetric-assisted chemometrics methods based on the localized gold nanoparticles surface plasmon resonance for fast simultaneous estimation of anti-hepatitis C virus drugs in their combined dosage form: A comparative study with HPLC method.

The present work describes a developed analytical method based on a colorimetric assay using gold nanoparticles (AuNPs) along with chemometric techniques for the simultaneous estimation of sofosbuvir (SOF) and ledipasvir (LED) in their synthetic mixtures and tablet dosage form. The applied chemometric approaches were continuous wavelet transform (CWT) and least squares support vector machine (LS-SVM). Characterization of AuNPs and AuNPs in combination with the drug was performed by UV-vis spectrophotometer, transmission electron microscopy (TEM), dynamic light scattering (DLS), and Fourier transform infrared (FTIR) spectroscopy. In the CWT method, the zero amplitudes were determined at 427 nm with Daubechies wavelet family for SOF (zero crossing point of LED) and 440 nm with Symlet wavelet family for LED (zero crossing point of SOF) over the concentration range of 7.5-90.0 µg/L and 40.0-100.0 µg/L with coefficients of determination (R2) of 0.9974 and 0.9907 for SOF and LED, respectively. The limit of detection (LOD) and limit of quantification (LOQ) of this method were found to be 7.92, 9.96 µg/L and 12.02, 30.2 µg/L for SOF and LED, respectively. In the LS-SVM model, the mean percentage recovery of SOF and LED in synthetic mixtures was 98.29 % and 99.25 % with root mean square error of 2.392 and 1.034, which were obtained by the optimization of regularization parameter (γ) and width of the function (σ) based on the cross-validation method. The proposed methods were also applied for the determination concentration of SOF and LED in the combined dosage form, recoveries were higher than 95 %, and relative standard deviation (RSD) values were lower than 0.4 %. The achieved results were statistically compared with those obtained from the high-performance liquid chromatography (HPLC) technique for the concurrent estimation of components through one-way analysis of variance (ANOVA), and no significant difference was found between the suggested approaches and the reference one. According to these results, simplicity, high speed, lack of time-consuming process, and cost savings are considerable benefits of colorimetry along with chemometrics methods compared to other ways.

Continuous wavelet transform and integration of discrete wavelet transform with principal component analysis and fuzzy inference system for the simultaneous determination of ethinyl estradiol and drospirenone in combined oral contraceptives.

In this study, the spectrophotometric method integrated with continuous wavelet transform (CWT) and coupled discrete wavelet transform (DWT) with fuzzy inference system (FIS) was developed for the simultaneous determination of ethinyl estradiol (EE) and drospirenone (DP) in combined oral contraceptives (COCs). The CWT approach was performed in the linearity range of 0.6-6 µg/mL for EE and 0.9 to 18 µg/mL for DP. Biorthogonal with an order of 1.3 (bior1.3) at a wavelength of 216 nm and Daubechies with an order of 2 (db2) at a wavelength of 278 nm were selected as the best wavelet families for obtaining the best zero crossing point for EE and DP, respectively. The limit of detection (LOD) of 0.7677 and 0.3222 µg/mL and the limit of quantification (LOQ) of 2.326 and 0.9765 µg/mL were obtained for EE and DP, respectively. The mean recovery of 103.24% and 99.77%, as well as root mean square error (RMSE) of 0.1896 and 0.1969, were found for EE and DP, respectively. In the DWT, the absorption of the mixtures was decomposed using different wavelets named db4, db2, Symlet2 (sym2), and bior1.3. Each of the wavelet outputs was dimension reduced by the principal component analysis (PCA) method and considered as FIS input. The wavelet of db4 with the coefficient of determination (R2) of 0.9979, RMSE of 0.0968, and mean recovery of 100.63% was chosen as the best one for the EE, while bior1.3 with R2 of 0.9955, RMSE of 0.4055, and mean recovery of 101.93% was selected for DP. These methods were successfully used to analyze the EE and DP simultaneously in tablet pharmaceutical formulation without any separation step. The suggested methods were compared with a reference method (HPLC) using analysis of variance (ANOVA) at a 95% confidence level, and no significant difference was observed in terms of accuracy. The suggested chemometric methods are reliable, rapid, and inexpensive, and can be used as an environmentally friendly alternative to HPLC for the simultaneous estimation of the mentioned drugs in commercial pharmaceutical products.

Colorimetric Concurrent Determination of Ultra-Trace Amounts of Pilocarpine and Timolol as Anti-Glaucoma Drugs in Binary Mixtures Using a Multivariate Calibration Approach Based on the Aggregation of Gold Nanoparticles.

BACKGROUND: To study the ultra-trace simultaneous determination of drugs, the colorimetric method in combination with chemometrics can be used. OBJECTIVE: In this study, a simple, rapid, and sensitive UV-Vis spectrophotometric method using gold nanoparticles (AuNPs) was introduced for the simultaneous determination of ultra-trace amounts of pilocarpine (PIL) and timolol (TIM) in binary mixtures and biological samples. METHODS: AuNPs interacted with components and the aggregation mode of NPs occurred, and, finally, the color change of the solution (red to gray) was observed with the naked eye without the most modern and expensive instruments. The characterization of AuNPs was evaluated by transmission electron microscopy (TEM) and dynamic light scattering (DLS). RESULTS: The validation of the colorimetric way was studied in the concentration range of 100-800 and 100-600 µg/L with good linearity equal to 0.9772 and 0.9891 for PIL and TIM, respectively. The limit of detection (LOD) was found to be 165.00 and 92.40 µg/L, where the limit of quantitation (LOQ) was 500.00 and 280.00 µg/L for PIL and TIM, respectively. The effect of some factors such as interaction time, the concentration of components, and the volume of buffer on absorbance was investigated. Partial least squares (PLS) as an efficient multivariate calibration method was combined with colorimetry for the simultaneous determination of PIL and TIM in binary mixtures. The optimum number of latent variables was selected by k-fold cross-validation based on minimum mean square error prediction (MSEP), and the number of components equal to 1 with MSEP of 1.085 and 0.763 was considered for PIL and TIM, respectively. The mean recovery was obtained at 100.20 and 101.55% for PIL and TIM, respectively. CONCLUSIONS: The colorimetric method can be introduced as a proper option for the simultaneous determination of components in pharmaceutical formulations and other samples. HIGHLIGHTS: A colorimetric method using AuNPs was proposed. The PLS method was coupled with a colorimetric method for the ultra-trace simultaneous estimation of PIL and TIM in binary mixtures. Ultra-trace amounts of PIL and TIM were also determined in biological samples. The proposed method is simple, fast, and less expensive than chromatography methods.

A Simple UV Spectrophotometric Method Based on Continuous Wavelet Transform and Multivariate Calibration Model for the Concurrent Analysis of Three Water-Soluble Vitamins in Fertility Supplements.

BACKGROUND: Owing to the presence of overlapping spectra in pharmaceutical components, classical spectrophotometry is hard for concurrent determination. The advance of chemometrics along with UV-Vis spectrophotometry has contributed to solving this problem. OBJECTIVE: In this study, a fast, easy, precise, accurate, low-cost, and eco-friendly spectrophotometric technique was introduced and validated for the simultaneous analysis of vitamin B6, vitamin B12, and vitamin C in fertility supplements for men and women using continuous wavelet transform (CWT) and partial least squares (PLS) techniques without using time-consuming extraction process and organic solvents. METHOD: In the CWT method, the zero-crossing technique was applied to obtain the optimum points for plotting calibration curves for each component. The validation of both methods was evaluated by analyzing several mixtures with different concentrations. The efficiency of the proposed methods was also surveyed on commercial capsules. RESULTS: Wavelet families, including Symlet (sym2) at 230, Biorthogonal (bior1.3) at 378 nm, and Daubechies (db2) at 261, were considered for vitamins B6, B12, and C, respectively. The linear range was found to be 8-20, 8-20, and 10-25 µg/mL with the coefficient of determination (R2) equal to 0.9982, 0.9978, and 0.9701 for B6, B12, and C, respectively. Low limit of detection (LOD) (<0.09 µg/mL) and limit of quantification (LOQ) <0.9 µg/mL were achieved. The mean recovery values in synthetic mixtures were from 98.38 to 98.89% and from 99.83 to 99.99%, where root-mean-square error (RMSE) of not more than 0.4 and 0.05 using the CWT and PLS methods, respectively. CONCLUSIONS: The obtained results from the commercial capsules, applying the suggested techniques, were compared to those yielded by the high-performance liquid chromatography (HPLC) method using the analysis of variance (ANOVA) test. According to the results, there are no significant differences, and they were in good agreement. According to all the mentioned cases, the proposed approaches can replace the time-consuming and costly HPLC method in quality control laboratories. HIGHLIGHTS: Green spectrophotometry coupling chemometrics methods were proposed. Simultaneous determination of three water-soluble vitamins in fertility supplements was done using these approaches. Rapidity, simplicity, low cost, and accuracy are the benefits of the proposed methods. A HPLC technique was used as a reference method to compare with the chemometrics methods.

Comparative Study of Continuous Wavelet Transform and Multivariate Calibration for the Simultaneous Spectrophotometric Determination of Tamsulosin and Solifenacin in Pharmaceutical Formulation and Biological Sample.

BACKGROUND: Spectrophotometry alone is not applicable for the simultaneous determination of drugs in a multicomponent pharmaceutical formulation owing to their overlap. OBJECTIVE: In this study, the combination of UV-Vis spectrophotometry and chemometric methods, including continuous wavelet transform (CWT) and partial least-squares (PLS) was presented for the simultaneous estimation of tamsulosin (TAM) and solifenacin (SOL) in synthetic mixtures, commercial formulations, and a biological sample. METHODS: The simultaneous spectrophotometric determination of TAM and SOL in binary mixtures, a real sample, and a biological sample was performed by applying CWT and PLS approaches. RESULTS: In the CWT method, two various wavelet families named Daubechies (db2) at wavelength 223 nm and Biorthogonal (bior1.3) at wavelength 227 nm based on the appropriate zero-crossing point were selected for TAM and SOL, respectively. The linear ranges of TAM and SOL were 0.25-4 µg/mL and 10-30 µg/mL, respectively. The LODs were 0.0459 µg/mL and 0.2085 µg/mL, while the LOQs were 0.3208 µg/mL and 0.6495 µg/mL for TAM and SOL, respectively. The average recovery values of 18 mixtures were 98.28% and 97.79% for TAM and SOL, respectively. Also, the root mean square error (RMSE) of both components was lower than 2.3. Based on the k-fold cross-validation in the PLS approach, the optimum number of components related to TAM and SOL were 9 and 5 with a mean square error prediction (MSEP) of 0.0153 and 0.0370, respectively. The mean recovery values of the test set were found to be 100.09% for TAM and 99.95% for SOL where RMSE values were 0.0064 and 0.0169 for TAM and SOL, respectively. CONCLUSION: Analysis of variance (ANOVA) was applied to the results of the real sample and there was no significant difference between the proposed methods and HPLC as a reference technique. The result obtained revealed that the proposed methods were found to be fast, facile, economical, and precise, and provide a suitable alternative to the HPLC technique for the concurrent determination of TAM and SOL in QC laboratories. HIGHLIGHTS: UV-Vis spectrophotometry combined with CWT and PLS was developed. Simultaneous analysis of TAM and SOL was performed using the proposed approaches. These methods were implemented on synthetic mixtures, commercial formulations, and a biological sample. ANOVA test was used to compare the suggested methods and the HPLC technique.

Rapid simultaneous analysis of anti human immunodeficiency virus drugs in pharmaceutical formulation by smart spectrophotometry based on multivariate calibration and least squares support vector machine methods.

In this study, two chemometrics methods, including partial least squares regression (PLS) and least squares support vector machine (LS-SVM) were applied for the simultaneous determination of zidovudine (ZDV) and lamivudine (LMV) in synthetic mixtures and anti-HIV pharmaceutical formulation. These approaches along with the spectrophotometric method were used to solve spectral overlapping problems between mentioned components. The results of PLS showed that the number of components for ZDV and LMV were 10 and 10 with mean square prediction error (MSPE) of 0.4045 and 2.1189, respectively. This method revealed recoveries ranging from 99.48% to 100.40% and 99.55% to 101.25% for ZDV and LMV, respectively. By applying leave-one-out cross-validation (LOO-CV), γ (regularization parameter) and σ2 (width of the function) values were found to be 50, 1500 and 210, 20 with root mean square error (RMSE) of 0.6156 and 0.3163 for ZDV and LMV, respectively. The mean recoveries obtained by the LS-SVM were 100.82% and 98.93% for ZDV and LMV, respectively. A comparison between the suggested methods and high-performance liquid chromatography (HPLC) as a reference technique was implemented, which did not show a significant difference. The results obtained in this research revealed that the chemometrics approaches can be efficient, simple, inexpensive, and precise for routine analysis and quality control of the drug.

Rapid Quantitative Determination Control Male Sexual Dysfunction Drug Content of Sildenafil and Tramadol Mixture by Spectrophotometry Along With Smart Chemometrics Approaches Compared to the HPLC Reference Method.

BACKGROUND: There are reports for the simultaneous estimation of sildenafil (SIL) and tramadol (TM) using chromatographic techniques. Some limitations of these methods are high cost and time, more usage of pollutant solvents, and complicated instruments. OBJECTIVE: Simultaneous determination of SIL and TM in the anti-sexual dysfunction pharmaceutical formulation using rapid and smart chemometrics approaches along with spectrophotometry. METHOD: In this study, a spectrophotometric analysis method based on continuous wavelet transform (CWT), partial least-squares (PLS), and radial basis function neural network (RBF-NN) was presented. RESULTS: In the CWT method, the Symlet (Sym2) and Daubechies (db2) wavelet families with wavelengths of 268 and 221 nm were considered the best families for SIL and TM, respectively. The limit of detection (LOD) and limit of quantitation (LOQ) values were found to be 0.0185, 0.0054 µg/mL and 0.0458, 0.3092 µg/mL for SIL and TM, respectively. The mean recovery values were 101.06 and 101.49% for SIL and TM, respectively. The results of PLS revealed that the root-mean-square error (RMSE) of SIL and TM was 0.0286 and 0.0635, respectively. Also, the mean recovery of both drugs was obtained over 99%. The mean square error (MSE) of RBF-NN was 5.88 × 10-29 and 4.61 × 10-27 for SIL and TM, respectively. CONCLUSIONS: A statistical comparative study conducted for the proposed methods with the high-performance liquid chromatography (HPLC) technique demonstrated no significant difference between these methods. The suggested approaches were simple, fast, accurate, and affordable. HIGHLIGHTS: Three smart UV spectrophotometric methods based on chemometrics were presented to determine SIL and TM simultaneously. The efficient chemometrics methods, including CWT, PLS, and RBF-NN, were used. The mentioned methods are rapid, simple, inexpensive, and accurate. The comparison was performed between the proposed models and HPLC technique.

The efficient removal of bisphenol A from aqueous solution using an assembled nanocomposite of zero-valent iron nanoparticles/graphene oxide/copper: Adsorption isotherms, kinetic, and thermodynamic studies.

In this study, nanoparticles of zero-valent iron (nZVI) along with graphene oxide (GO) and copper (Cu) was synthesized to apply as a promising adsorbent for the rapid removal of bisphenol A (BPA) from aqueous solution. The characteristics of nZVI-GO-Cu were analyzed by field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD), and vibrating sample magnetometer (VSM). The average particle size of nZVI-GO-Cu was found to be 20.89 nm. The effective experimental variables such as pH, adsorbent dosage, contact time, initial BPA concentration, and temperature were surveyed to assess optimum conditions. Results revealed that the maximum removal percentage was obtained at pH of 7, adsorbent dosage of 0.2 g, contact time of 10 min, the BPA concentration of 10 mg/L, and a temperature of 35 °C as optimum conditions. Experimental data were fitted to the Langmuir and pseudo second-order models with a coefficient of determination (R2) equal to 1 and 0.995, respectively. The obtained maximum adsorption capacity (qmax) of the Langmuir isotherm was 21.59 mg g-1. Thermodynamic parameters under the various temperatures confirmed that the adsorption process was endothermic (ΔH = 17,459.4 J/mol and ΔS = 61.23 J/mol/K) and spontaneous (ΔG < 0). As a conclusion, nZVI-GO-Cu can be selected as an efficient adsorbent for the treatment of aqueous media from BPA and the other pollutants, due to its low-cost, high removal efficiency (97%), and rapid adsorption with the minimum time of 10 min compared with the other adsorbents.

An intelligent method based on feed-forward artificial neural network and least square support vector machine for the simultaneous spectrophotometric estimation of anti hepatitis C virus drugs in pharmaceutical formulation and biological fluid.

This study proposed simple and reliable spectrophotometry method for simultaneous analysis of hepatitis C antiviral binary mixture containing sofosbuvir (SOF) and daclatasvir (DAC). This technique is based on the use of feed-forward artificial neural network (FF-ANN) and least square support vector machine (LS-SVM). FF-NN with Levenberg-Marquardt (LM) and Cartesian genetic programming (CGP) algorithms was trained to determine the best number of hidden layers and the number of neurons. This comparison demonstrated that the LM algorithm had the minimum mean square error (MSE) for SOF (1.59 × 10-28) and DAC (4.71 × 10-28). In LS-SVM model, the optimum regularization parameter (γ) and width of the function (σ) were achieved with root mean square error (RMSE) of 0.9355 and 0.2641 for SOF and DAC, respectively. The coefficient of determination (R2) value of mixtures containing SOF and DAC was 0.996 and 0.997, respectively. The percentage recovery values were in the range of 94.03-104.58 and 94.04-106.41 for SOF and DAC, respectively. Statistical test (ANOVA) was implemented to compare high-performance liquid chromatography (HPLC) and spectrophotometry, which showed no significant difference. These results indicate that the proposed method possesses great potential ability for prediction of concentration of components in pharmaceutical formulations.

Improved spectral resolution for the rapid simultaneous spectrophotometric determination of sofosbuvir and daclatasvir as anti hepatitis C virus drugs in pharmaceutical formulation and biological fluid using continuous wavelet and derivative transform.

In this study, the simultaneous spectrophotometric estimation of Sofosbuvir (SOF) and Daclatasvir (DAC) in synthetic mixtures and tablet formulation in the presence of overlapping spectra was performed based on continuous wavelet transform (CWT) and derivative spectrophotometry (DS) methods without any separation process. The Coiflet (Coif2) and Daubechies (Db3) wavelet families with wavelength of 256 nm and 218 nm were obtained as the best families for the simultaneous determination of SOF and DAC, respectively. Also, the first derivative absorption spectra revealed the best results corresponding to the analysis of SOF and DAC at 237 nm and 291 nm, respectively. The ranges of limit of detection (LOD) and limit of quantitation (LOQ) related to the CWT and DS methods were 2.45 × 10-3 to 0.5054 and 6.91 × 10-3 to 0.6027, respectively. Mean recovery values of SOF and DAC in synthetic mixtures for CWT approach were 98.55%, 98.09% and in DS method were 98.78% and 95.83%, respectively. Real samples, including Sovodak tablet and urine was used for accurate simultaneous determination of the mentioned components. Analyzing Sovodak tablet was implemented using high-performance liquid chromatography (HPLC) as a reference method that the results were near to the CWT and DS methods. In order to investigate the existence of significant differences between the methods, analysis of variance (ANOVA) test at the 95% confidence level was performed but no significant differences were observed. In addition, the amounts of SOF and DAC in the complex matrix of biological sample were well predicted by the proposed methods.

The application of continuous wavelet transform based on spectrophotometric method and high-performance liquid chromatography for simultaneous determination of anti-glaucoma drugs in eye drop.

In this study, a fast, low-cost, accurate, and precise spectrophotometric method based on the continuous wavelet transform (CWT) was assayed to determine dorzolamide (DOR) and timolol (TIM) in an eye drop sample simultaneously. Different wavelet families were investigated to select the best family for analyzing the DOR and TIM. The Mexican hat wavelet (MHW) family with the wavelength of 281 nm and Gaussian wavelet family (gaus2) in the wavelength of 267 nm were found for the simultaneous analysis of DOR and TIM, respectively. Mean recovery values of synthetic mixtures were found 97.44%±2.63 and 99.18%±4.00 for DOR and TIM, respectively. The root mean square errors (RMSE) of DOR and TIM were achieved 0.5550 and 0.3306, respectively. Eye drop as a real sample was analyzed by spectrophotometry coupled with the CWT technique, as well as high-performance liquid chromatography (HPLC) as a reference method. The obtained results were compared with each other by the one-way analysis of variance (ANOVA) test and there was no significant difference between them.

Simultaneous ultra-trace quantitative colorimetric determination of antidiabetic drugs based on gold nanoparticles aggregation using multivariate calibration and neural network methods.

In this study, a simple and rapid method was investigated for the simultaneous ultra-trace colorimetric determination of Metformin (MET) and Sitagliptin (STG) based on the aggregation of gold nanoparticles (AuNPs). The Morphology and size distribution of synthesized AuNPs before and after adding drug (Zipmet) were monitored using transmission electron microscopy (TEM) and dynamic light scattering (DLS), respectively. By adding a drug, the absorption peak was shifted from 520 to 650 nm. The colorimetric method along with partial least squares (PLS) as a multivariate calibration method, as well as neural network time series were applied to estimate MET and STG simultaneously. The percentage of the mean recovery and root mean square error (RMSE) of the test set of mixtures related to the MET and STG were obtained 99.96, 1.1301 and 99.77, 1.0106, respectively. On the other hand, the regression coefficient (R2) of the training, validation, and test sets corresponding to the artificial neural network (ANN) were close to one for both components. Eventually, the proposed method was compared with a reference technique named high-performance liquid chromatography (HPLC) by analysis of variance (ANOVA) test and there was no significant difference between them.

Determination of 2,4-Dichlorophenoxyacetic acid in food and water samples using a modified graphene oxide sorbent and high-performance liquid chromatography.

In the present work, dispersive micro-solid phase extraction (D-µ-SPE) method using magnetic graphene oxide tert-butylamine (GO/Fe3O4/TBA) nanocomposite, as an efficient sorbent, was applied for determining 2,4-dichlorophenoxyacetic acid (2,4-D) in water and food samples. Detection was carried out using high-performance liquid chromatography (HPLC) instrument. Influential parameters of D-µ-SPE such as sorbent and its amount, elution solvent and its volume, adsorption and desorption times and pH of sample solution were investigated and optimized. Under the optimized conditions, limit of detection and quantitation values were 0.007 and 0.02 µg/mL, respectively. Recovery data for several real samples were obtained within the range of 88.0-94.0% with a relative standard deviation (RSD) less than 7.5%. The proposed method was successfully applied to quantitative determination of 2,4-D in several vegetables and water samples.

Preparation and modification of forcespun polypropylene nanofibers for adsorption of uranium (VI) from simulated seawater.

In this paper, polypropylene (PP) nanofibers were prepared using the melt forcespinning technology by a handmade device. Then, the surface of PP nanofibers was grafted through the high energy electron beams (EB) pre-irradiation method by acrylonitrile and methacrylic acid monomers with grafting percentage of 145.55%. The 92% of grafted cyano functional groups on nanofibers were converted to amidoxime groups, then modified by an alkaline solution. Characterization and surface morphology of nanofibers were investigated by Fourier Transform Infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The produced adsorbent was used to adsorb U(VI) ions from simulated seawater. The maximum adsorption was 83.24 mg/g in the optimal time of 60 min and optimal pH of 4. The optimum desorption efficiency was 80% in HCl 0.5 M. The kinetic data in optimum conditions showed that the adsorption followed an S-shaped kinetic model. The Adsorption equilibrium studies presented S-shape isotherm model that confirmed the adsorption occurs both on the adsorbent surface and in its pores The thermodynamic studies indicated spontaneous adsorption of uranyl ions and the higher efficiency adsorption at higher temperatures. The selectivity of adsorbent for metal ions followed the order V(V)>U(VI)>CO(II)>Ni(II)>Fe(II). These results shows that the prepared and modified nanofibers in this work can be considered as an effective and promising adsorbents for removal of uranium ions from seawater with high efficiency.

Using artificial neural network and multivariate calibration methods for simultaneous spectrophotometric analysis of Emtricitabine and Tenofovir alafenamide fumarate in pharmaceutical formulation of HIV drug.

Spectrophotometric analysis method based on artificial neural network (ANN), partial least squares regression (PLS) and principal component regression (PCR) models was proposed for the simultaneous determination of Emtricitabine (ETB) and Tenofovir alafenamide fumarate (TAF) in human immunodeficiency virus (HIV) drug. An artificial neural network consisting of two, five, and seven layers with 2,3,5,7, and 9 neurons was trained by applying a feed forward back-propagation learning. In this method, Levenberg-Marquardt (LM) and gradient descent with momentum and adaptive learning rate back propagation (GDX) algorithms were used. Statistical parameters indicated that the ability of LM was better than GDX algorithm. Also, root mean square error (RMSE) and recovery (%) of the PLS and PCR methods showed that PLS has worked better than PCR. The proposed models were compared to the high- performance liquid chromatography (HPLC) as a reference method. Furthermore, the obtained results of the one-way analysis of variance (ANOVA) test at the 95% confidence level represented that there was no significant difference between the proposed and reference methods.

Determination of trace amounts of aromatic amines after magnetic solid-phase extraction using silver-modified Fe3 O4 /graphene nanocomposite.

In this work, a fast and simple magnetic dispersive solid phase extraction methodology was developed utilizing Ag@magnetite nanoparticles@graphene nanocomposite as an efficient magnetic nanosorbent for preconcentration and determine of five aromatic amines in water samples. The sorbent was characterized by diverse characterization techniques. After the extraction, high-performance liquid chromatography with UV detection was utilized to analysis the aromatic amines. The effects of different factors on the extraction process were studied thoroughly via design of experiment and desirability function. Detection limits and linear dynamic ranges were obtained in the range of 0.10-0.20 and 0.3-300 µg/L, respectively. The relative standard deviations (n = 5) were in the range of 4.3-6.5%. Eventually, the method was employed for determination of target aromatic amines in various water samples.

Optimization of ultrasonic assisted extraction of fatty acids from Aesculus hippocastanum fruit by response surface methodology.

The effectiveness of ultrasound-assisted extraction (UAE) of Aesculus hippocastanum fruit oil was investigated using methanol as a solvent. The study compared extraction yields using UAE and methanol with soxhlet. The effects of three extraction parameters, namely temperature, time and the ratio of solvent (volume) to plant material (weight) were optimized using both a Box-Behnken design (BBD) and response surface methodology (RSM). The highest extraction yields were obtained for UAE at 60 °C and 56.5 min with a ratio of solvent to plant material weight of 45:1. The extraction yield using UAE varied by 21.82% (w/ w) but was, regardless, significantly greater than Soxhlet extraction.

Electrospun composite PLLA/Oyster shell scaffold enhances proliferation and osteogenic differentiation of stem cells.

In bone tissue engineering, bioceramics are of the most widely used materials for treatment of bone defects clinically. The composites of bioceramic/polymer fibrous scaffolds have been designed and developed to fulfill the mechanical and biological requirements of the damaged tissue. In the present study, oyster shell (OS) as a bioceramic in combination with the biodegradable and biocompatible poly (l-lactide) has been used to prepare a new tissue-engineered composite. The morphology, porosity, water contact angle and mechanical properties of scaffolds were investigated. Mesenchymal stem cells were also cultured on fabricated scaffolds to evaluate their potential to support cell proliferation and osteogenic differentiation. The SEM results indicated that the electrospun scaffolds were nanostructured and the OS were oriented along the fiber axis. The tensile strength and also the increased surface hydrophilicity of scaffolds after plasma treatment were suitable for tissue engineering applications. MTT assay demonstrated that the fabricated scaffolds were capable of supporting stem cell attachment and proliferation. Biomineralization measurements demonstrated the enhanced osteogenic differentiation of stem cells on composite PLLA/OS scaffolds. Taken together, these scaffolds were shown to hold promising potential for the treatment of bone defects in vivo.

Use of continuous wavelet transform approach for simultaneous quantitative determination of multicomponent mixture by UV-Vis spectrophotometry.

In the present paper, a multicomponent analysis approach based on spectrophotometry method was developed for simultaneous determination of Guaifenesin (GU), Chlorpheniramine (CHL) and Pseudoephedrine (PSE) without any separation steps. The method under study is signal processing method based on Continuous Wavelet Transform (CWT) coupled with zero cross point technique. In this paper, CWT method was tested by synthetic ternary mixtures and was applied to the commercial cough syrup as a real sample and assessed by applying the standard addition technique. For demonstrate the accuracy of the results, other applications of signal processing, such as Derivative Transform (DT), Partial Least Squares (PLS) regression and Principal Components Regression (PCR) were used as comparative methods. Afterwards, the obtained results from analyzing the cough syrup by all methods were compared to the High-Performance Liquid Chromatography (HPLC) as a reference method. One-way analysis of variance test at 95% confidence level showed no significant differences between CWT and other applications.

A detailed structural study of cytotoxicity effect of ionic liquids on the leukemia rat cell line IPC-81 by three dimensional quantitative structure toxicity relationship.

In the present study, a very thorough and in-depth three-dimensional quantitative structure-toxicity relationship (3D-QSTR) analysis has been implemented to make a correlation between the structural information of the ionic liquids (ILs) and their cytotoxicity towards Leukemia rat cell line IPC-81, as one of the ILs' toxicological consequences. To do this, alignment free GRid-INdependent Descriptors (GRINDs), which were derived from molecular interaction fields (MIFs), were correlated to the cytotoxicity values by partial least squares (PLS) and support vector regression (SVR). Genetic algorithm (GA), as a powerful linear tool, was used to select the best and interpretative subset of variables for the predictive model building. The selected variables with the capability to screen the effective structural features, showed direct and inverse contribution to the cytotoxicity. In silico modeling can reduce the amount of cellular testing necessary by predicting the toxicological functions of the chemical structures. Acceptable predictions of both internal and external validation sets made it possible to develop the predictive models for a large set of 269 diverse ILs containing 9 cationic cores and 44 types of anions. The constructed 3D-QSTR models use simple and interpretable descriptors to provide an in-depth and mechanistic interpretation of structural characteristics. This helps provide a clear understanding of the cytotoxicity effects of the understudy ILs. The effects of the nature of the cations, anions, and substituents on the cytotoxicities were evaluated and discussed.