Development and validation of a rapid HPLC method for the determination of ketotifen in pharmaceuticals

In the present study, a simple, sensitive, rapid, and stability-indicating high performance liquid chromatographic (HPLC) method with ultraviolet detection for the analysis of ketotifen was developed and validated. The method was applied to the determination of ketotifen in pharmaceutical formulations (tablets and syrups). The HPLC method utilized isocratic elution technique with a reversed phase C8 column, detection at 297 nm and a mixture of methanol, triethylamine phosphate buffer (pH 2.8; 0.04 M), and tetrahydrofuran (43: 55: 2, v/v/v) as mobile phase at a flow rate of 1.2 mL/min. Total analysis time was about 7 min with typical retention time of ketotifen of about 5 min. The method was validated for selectivity, linearity, accuracy, and precision following International Conference of Harmonization, 1996 (ICH) recommendations. Due to its simplicity and accuracy, the method can be used for routine quality control analysis.     

Chromium speciation in environmental samples by solid phase extraction on Chromosorb 108

In the present work, a solid phase extraction system has been proposed for speciation of Cr(III) and Cr(VI) in the real samples. The procedure based on the adsorption of chromium(III) as dithizonate chelate on the Chromosorb 108 resin. After reduction of Cr(VI) by concentrated H2SO4 and ethanol, the system was applied to the total chromium. Cr(VI) was calculated as the difference between the total Cr content and the Cr(III) content. The influences of the analytical parameters including pH of the aqueous solution, amounts of dithizone, eluent type, sample volume and flow rates of the sample and eluent solution were investigated. No considerable interferences have been observed from other investigated anions and cations on the chromium speciation. The adsorption capacity of sorbent was 4.50 mg/g Cr(III). The detection limit of Cr(III) is 0.75 microg/L. The proposed method was applied to the speciation of chromium in environmental samples including natural waters and total chromium preconcentration in microwave digested Turkish tobacco, coffee and soil samples with satisfactory results. In order to verify the accuracy of the method, two certified reference materials (NIST SRM 1573a Tomato Leaves and RTC-CRM 025-050 Metals on Soil) were analyzed and the results obtained were in good agreement with the certified values. The relative errors and relative standard deviations were below 5% and 9%, respectively.     

An Optimal Algorithm for Resource Allocation in D2D Communication

The number of mobile devices accessing wireless networks is skyrocketing due to the rapid advancement of sensors and wireless communication technology. In the upcoming years, it is anticipated that mobile data traffic would rise even more. The development of a new cellular network paradigm is being driven by the Internet of Things, smart homes, and more sophisticated applications with greater data rates and latency requirements. Resources are being used up quickly due to the steady growth of smartphone devices and multimedia apps. Computation offloading to either several distant clouds or close mobile devices has consistently improved the performance of mobile devices. The computation latency can also be decreased by offloading computing duties to edge servers with a specific level of computing power. Device-to-device (D2D) collaboration can assist in processing small-scale activities that are time-sensitive in order to further reduce task delays. The task offloading performance is drastically reduced due to the variation of different performance capabilities of edge nodes. Therefore, this paper addressed this problem and proposed a new method for D2D communication. In this method, the time delay is reduced by enabling the edge nodes to exchange data samples. Simulation results show that the proposed algorithm has better performance than traditional algorithm.     

Celtek clay as sorbent for separation-preconcentration of metal ions from environmental samples

The sorption conditions including pH of the aqueous solution, sample volume, etc., on Celtek clay of copper(II), cadmium(II), lead(II), chromium(III), nickel(II) and cobalt(II) ions from environmental samples has been studied. The effects of electrolytes as matrix on the preconcentration were also investigated with the recoveries >95%. The 3 sigma detection limits for copper, cadmium, lead, chromium, nickel and cobalt ions were found to be 0.25, 0.32, 0.73, 0.45, 0.50 and 0.41 microg/l, respectively. The relative standard deviation was <10% for the determination of analytes. The procedure was validated by analysis of a NRCC-SLRS 4 Riverine Water, SRM 1573a Tomato leaves and IAEA 336 Lichen standard reference materials. The developed method was successively utilized for the determination of Cu(II), Cd(II), Pb(II), Cr(III), Ni(II) and Co(II) in various samples including natural waters, wheat and human hair by flame atomic absorption spectrometry (FAAS) with satisfactorily results (recoveries>95% and R.S.D.'s<10%).     

Artificial Algae Optimization with Deep Belief Network Enabled Ransomware Detection in IoT Environment

The Internet of Things (IoT) has gained more popularity in research because of its large-scale challenges and implementation. But security was the main concern when witnessing the fast development in its applications and size. It was a dreary task to independently set security systems in every IoT gadget and upgrade them according to the newer threats. Additionally, machine learning (ML) techniques optimally use a colossal volume of data generated by IoT devices. Deep Learning (DL) related systems were modelled for attack detection in IoT. But the current security systems address restricted attacks and can be utilized outdated datasets for evaluations. This study develops an Artificial Algae Optimization Algorithm with Optimal Deep Belief Network (AAA-ODBN) Enabled Ransomware Detection in an IoT environment. The presented AAA-ODBN technique mainly intends to recognize and categorize ransomware in the IoT environment. The presented AAA-ODBN technique follows a three-stage process: feature selection, classification, and parameter tuning. In the first stage, the AAA-ODBN technique uses AAA based feature selection (AAA-FS) technique to elect feature subsets. Secondly, the AAA-ODBN technique employs the DBN model for ransomware detection. At last, the dragonfly algorithm (DFA) is utilized for the hyperparameter tuning of the DBN technique. A sequence of simulations is implemented to demonstrate the improved performance of the AAA-ODBN algorithm. The experimental values indicate the significant outcome of the AAA-ODBN model over other models.     

Removal of toxic aqueous ions using amorphous AlPO4

Aluminium phosphate (AlPO₄) was characterized using X-ray diffractometry (XRD), Fourier Transform infrared (FTIR), point of zero charge (PZC) and dissolution studies. XRD showed the sample to be amorphous, FTIR confirmed the presence of OH groups on the surface and PZC was determined at pH 3.45. The dissolution study illustrated a decrease in dissolution with an increase in the pH. Potentiometric titration data were fit to the Gaines–Thomas equation, which showed that AlPO₄ is a weakly acidic ion exchanger. Sorption studies were carried out at pH 4–6 and temperatures 293–323 K. The uptake of metal ions was observed to increase with an increase in the pH and temperature. The surface selectivity towards metal ions was found in the order Pb²⁺> Cu²⁺> Cd²⁺. Sorption data were fit to the new equation derived from the proposed mechanism for metal ion uptake. Various parameters such as stoichiometry of the surface H⁺ ion release, equilibrium constant, standard enthalpy, entropy and free energy changes were evaluated from the plots. The values of all these parameters were found to be closely related to the values reported in the literature.     

模拟定向凝固生长速率对杆形Mn-Bi合金共晶间距的影响

为了深入了解定向凝固过程生长速率对杆形Mn-Bi合金共晶间距的影响，开展了试验和数值模拟研究工作，以期初步明确在地球上试验得到的杆形共晶间距和在外层空间(航天飞机上)同样试验条件下得到的杆形共晶间距发生变化这样一个事实的机理。在杆形MnBi共晶相和Bi基体生共前沿，用传盾方程计筑了Mn在合金液中的浓度场，得到了液、固两相间台式界面前沿Mn的等浓度曲线，进而依据Jackson-Hunt研究的理论模型计算出杆形共晶间距。试验和数值模拟的结果显示，规则生长时，随着Peclet数Λ的不断增加,杆形共晶间距逐渐减少，试验与模拟的结果吻合良好。Λ数还可在将来被用来模拟计算该合金凝固时非规则生长时的情况。     

Selective separation and concentration of Pd(II) from Fe(III), Co(II), Ni(II), and Cu(II) ions using thiourea‐formaldehyde resin

Thiourea‐formaldehyde (TUF), a well‐known chelating resin, has been synthesized and it was used in the adsorption, selective separation, and concentration of Pd(II) ions from Fe(III), Co(II) Ni(II), and Cu(II) base metal ions. The composition of the synthesized resin was determined by elemental analysis. The effect of initial acidity/pH and the adsorption capacity for Pd(II) ions were studied by batch technique. The adsorption and separation of Pd(II) were then examined by column technique. FTIR spectra and SEM/EDS analysis were also recorded before and after the adsorption of Pd(II). The optimum pH was found to be 4 for the adsorption. The adsorption data fitted well to the Langmuir isotherm. The maximum adsorption capacity of the TUF resin for Pd(II) ions was found to be 31.85 mg g⁻¹ (0.300 mmol g⁻¹). Chelating mechanism was effective in the adsorption. Pd(II) ions could be separated efficiently from Fe(III), Cu(II), Ni(II), and Co(II) ions using TUF resin. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Evaluating sociotechnical dynamics in a simulated remotely-piloted aircraft system: a layered dynamics approach

As coordination mechanisms change and technology failures occur, a sociotechnical system must reorganise itself across human and technological layers to maintain effectiveness. We present a study examining reorganisation across communication, controls and vehicle layers of a remotely-piloted aircraft system (RPAS) using a layered dynamics approach. Team members (pilot; navigator; photographer) performed 5 simulated RPAS missions using different operator configurations, including all-human and human-autonomy teams. Reorganization (operationally defined using entropy) time series measured the changing system reorganisation profiles under different operator configurations and following autonomy failures. Correlations between these reorganisation profiles and team effectiveness scores describe the manner in which the system had to be coordinated to maintain effectiveness under these changing conditions. Four unplanned autonomy failures were analysed to visualise system reorganisation following a technology failure. With its objective and real-time modelling and measurement capabilities, layered dynamics complements existing systems thinking tools for understanding sociotechnical complexity and enhancing system effectiveness.

Practitioner summary: A layered dynamics approach for understanding how a sociotechnical system dynamically reorganises itself is presented. The layered dynamics of RPAS were analysed under different operator configurations and following autonomy failures. Layered dynamics complements existing system-thinking tools for modelling sociotechnical system complexity and effectiveness.

Abbreviation: RPAS: remotely-piloted aircraft system; HIS: human-systems integration; EAST: event analysis of systemic teamwork; H1: hypothesis 1; H2: hypothesis 2; H3: hypothesis 3; CERTT-STE: cognitive engineering research on team tasks--synthetic task environment; AVO: air vehicle operator; PLO: payload operator; DEMPC: data exploitation, mission planning, and communications; ACT-R: adaptive control of thought-rational; sec: seconds; ANOVA: analysis of variance     

Performance of dairy cows fed roasted sunflower seed

The objectives of this study were to determine the effects on milk yield, milk composition, ruminal fermentation and total tract nutrient utilization of feeding roasted whole sunflower seed to dairy cows. Three diets were formulated: a control diet with no sunflower seed (NSF), a raw sunflower seed diet (USF) and a roasted sunflower seed diet (RSF). The level of sunflower seed in USF and RSF was 78 g kg^?1 of dry matter (DM). The effects of dietary treatments on yield and composition of milk were determined using nine Holstein cows in three 3 × 3 Latin squares. Three ruminally fistulated cows were used to determine the effects of dietary treatments on ruminal fermentation and total tract nutrient digestibilities. Cows fed sunflower seed diets consumed 8% less (P < 0.05) DM but produced similar amounts of milk as cows fed NSF. However, milk fat content (30.7 vs 33.5 g kg^?1) and yield (1.33 vs 1.47 kg day^?1) were lower (P < 0.05) for cows fed USF and RSF than for those fed NSF. Supplemental sunflower seed had no effect on concentrations and yields of other milk components. The concentrations of short‐chain (C_4:0 to C_12:0) and medium‐chain (C_14:0 to C_16:0) fatty acids were, respectively, 27% and 29% lower (P < 0.05) while those of long‐chain fatty acids (C_18:0 to C_18:3) were 51% higher (P < 0.05) in the milk of cows fed USF and RSF than for cows fed NSF. Ruminal pH, ammonia N and total volatile fatty acids were not affected by dietary treatments. Feeding sunflower seed (USF or RSF) reduced (P < 0.05) the concentration of acetate and increased (P < 0.05) the concentration of propionate. Total tract nutrient digestibilities were not affected by sunflower seed supplementation or by heat treatment. Supplementing dairy cow diets with unheated or roasted sunflower seed improved the efficiency of milk production and increased concentrations of long‐chain and polyunsaturated fatty acids. Feeding sunflower seed at up to 78 g kg^?1 of diet DM had no adverse effects on nutrient utilization. Roasting had no additional benefits on milk yield or milk fatty acid composition. Copyright © 2004 Society of Chemical Industry