Graphical Optimization Research Articles

Ginger essential oil nanoemulsions: Preparation and physicochemical characterization and antibacterial activities evaluation

AbstractThe aim of this study was the preparation of ginger (Zingiber officinale) essential oil nanoemulsions through the bottom up solvent displacement technique. The effects of main processing parameters, namely, the homogenization and evaporation rotating speeds at solvent removing step were also evaluated on mean particle size, polydispersity (PDI), zeta potential, turbidity, antioxidant, and antibacterial activities against S. aurous and E. coli of gained nanoemulsions, using response surface method (RSM). The ginger essential oil nanoemulsions were successfully synthesized, in the particle sizes ranged from 68 to 1,035 nm. The second polynomial models were then suggested in order to predict the studied response characteristics by selected process independent parameters. The multiple graphical optimization suggested that using mixing the organic and aqueous phases in the ranges of 800–1,000 rpm and rotating evaporator at the speeds from 75 to 85 rpm would lead to production of the most desirable nanoemulsions. The observed insignificant differences between the experimental data and calculated ones by models confirmed the suitability and accuracy of suggested models. Thus, it was concluded that the prepared nano‐sized ginger essential oil can be effectively used in several food systems as preservative or flavor modifier agent.Practical ApplicationsThe ginger essential oil nanoemulsions were fabricated through a cost effective and simple nano‐precipitation technique and the gained nano‐sized, water dispersible, chemically stabilized product with desired flavor and good either antioxidant or antibacterial activities, can be successfully used in various food and beverage formulations as preserver, nutrition enhancer and flavor.

Graphic Library Optimization for MIPS Architecture

The aim of this paper and research was to analyse the efficiency of the compiler-generated code for the graphics library and to present results obtained by optimization for the MIPS (Million Instructions Per Second) architecture. Libpng is the official Portable Network Graphics reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. Given the data structure in the PNG files, as well as the capabilities of the MIPS instruction set, it was expected that significant improvements could be made. Graphic library libpng is optimized by using MIPS instruction set extension and tested on MIPS Malta 74K platform. Test results show, that by using MIPS optimization test, execution times are substantially improved. Our libpng optimization have achieved performance increase of 10 %–78 % depending on optimized routine.

Potential of image optimization on websites of rural tourism facilities in Poland

The success of a rural tourism business largely depends on promotional activities. Having developed a tourist product, owners of rural tourism facilities should therefore inform the buyers about it. Usually, they rely on websites and social media for this purpose. However, for a website to fulfill its function, it should be of high quality. The improvement of website quality can be achieved through measures which include search engine optimization (SEO) and content and graphics optimization. The purpose of this paper is to assess the potential of image optimization on websites of Polish rural tourism facilities. The research covered 1000 paid domain websites. The largest part of the sites surveyed were rated good in terms of graphic file optimization. In spite of this, it was possible to reduce the size of graphic files covered by this study and used in the research model by as much as 67% without significantly deteriorating their quality. This research showed that image optimization has no direct impact on the outcome of an SEO audit, and that images can be optimized even for websites with high final scores.

Optimal Design of Water Quality Monitoring Networks in Semi-Enclosed Estuaries.

The semi-enclosed estuary is very susceptible to changes in the physical and environmental characteristics of the inflow from the land. Therefore, continuous and comprehensive monitoring of such changes is necessary for managing the estuary. Nevertheless, the procedure or framework has not been proposed appropriately to determine how many instruments are necessary and where they need to be monitored and standardized to detect critical changes. The present work proposes a systematical strategy for the deployments of the monitoring array by using the combination of graphical optimization with the objective mapping technique. In order to reflect the spatiotemporal characteristics of the bay, the representative variables and eigenvectors were determined by the Empirical Orthogonal Function (EOF), and the cosine angle among them calculated and used as a design index of optimization. At the recommended locations, the sampled representative variables were interpolated to reconstruct their spatiotemporal distribution and compared with the true distribution. The analysis confirmed that the selected locations, even with a minimal number of points, can be used for on-site monitoring. In addition, the present framework suggests how to determine installable regions for real-time monitoring stations, which reflect the global and local characteristics of the semi-enclosed estuary.

Development and Optimization of Stereoselective Liquid Chromatographic Method for Chiral Separation of (±)-cetirizine and Enantiopurity Assessment of R-levocetirizine

R-levocetirizine, the racemic switch of (±)-cetirizine, is a potent H1-receptor antagonist. R-levocetirizine is currently marketed as oral dosage forms used to prevent and treat allergic conditions. In the present study, a stereoselective HPLC method was developed and optimized for the determination of cetirizine enantiomers in bulk and formulations by employing a chemometric tool. Chromatographic separation was carried out on a Chiralpak AS-3R analytical column (150 × 4.6 mm i.d., 3 µm). D-optimal mixture design was employed to study the effect of solvent composition, viz. acetonitrile (75–85%, v/v), MeOH (5–15%, v/v) and water (5–15%, v/v), by keeping other factors constant, such as mobile phase additives, flow rate (1.0 mL/min) and wavelength (235 nm) on output responses: retention factor and resolution of S- and R-enantiomers and analysis time. The mobile phase system comprising of acetonitrile−methanol−water−acetic acid−diethylamine (85 : 10 : 5 : 0.1 : 0.1, v/v) was selected as optimal by a graphical optimization trade-off technique. The proposed method was validated according to the ICH guidelines and successfully applied for the quantitation of cetirizine enantiomers in pharmaceutical dosage forms. The present study resulted in a fast and efficient liquid chromatographic method for the enantiopurity assessment of R-levocetirizine in real samples.

The Optimum Performance of Building Integrated Photovoltaic (BIPV) Windows Under a Semi-Arid Climate in Algerian Office Buildings

Recently, Building Integrated Photovoltaic (BIPV) windows have become an alternative energy solution to achieve a zero-energy building (ZEB) and provide visual comfort. In Algeria, some problems arise due to the high energy consumption levels of the building sector. Large amounts of this energy are lost through the external envelope façade, because of the poorness of the window’s design. Therefore, this research aimed to investigate the optimum BIPV window performance for overall energy consumption (OEC) in terms of energy output, heating and cooling load, and artificial lighting to ensure visual comfort and energy savings in typical office buildings under a semi-arid climate. Field measurements of the tested office were carried out during a critical period. The data have been validated and used to develop a model for an OEC simulation. Extensive simulations using graphical optimization methods are applied to the base-model, as well as nine commercially-available BIPV modules with different Window Wall Ratios (WWRs), cardinal orientations, and tilt angles. The results of the investigation from the site measurements show a significant amount of energy output compared to the energy demand. This study revealed that the optimum BIPV window design includes double-glazing PV modules (A) with medium WWR and 20% VLT in the southern façade and 30% VLT toward the east–west axis. The maximum energy savings that can be achieved are 60% toward the south orientation by double-glazing PV module (D). On the other hand, the PV modules significantly minimize the glare index compared to the base-model. The data extracted from the simulation established that the energy output percentages in a 3D model can be used by architects and designers in early stages. In the end, the adoption of optimum BIPV windows shows a significant enough improvement in their overall energy savings and visual comfort to consider them essential under a semi-arid climate.

Transitioning of localized renewable energy system towards sustainable hydrogen development planning: P-graph approach

This study aimed to transition localized hybrid renewable energy microgrid system in multiple regions by integrating excess renewable electricity and carbon dioxide generated with biogas produced in wastewater treatment plant. The integrated optimization network in this contribution addresses the following aspects: (1) biogas supply-demand distribution network, (2) hydrogen production technology allocation involving steam methane reforming and electrolysis, (3) carbon dioxide allocation, and (4) utilization of external resources. The proposed framework is mathematically expressed as a mixed-integer linear programming problem to minimize total annual cost which will be solved by graphical optimization approach, P-graph. A case study of the existing petrochemical industry complex in South Korea has been applied to the developed model. Feasible configuration for meeting base hydrogen demand (7200 tons H2/year) has been proposed with total annual cost of 75,772,460 US $/year. Apart from base hydrogen demand, the developed model is verified with the increase of hydrogen demand for 10%, 20%, 30%, and 40%. Nonetheless, scenario of tight environmental regulations enforcement has been established among all cases where carbon dioxide emitted within the system will be captured and sequestrated. Pareto Frontier Analysis and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) have been implemented to enhance the overall sustainability by re-ranking the pool of near-optimal solutions to propose new sustainable configuration with the consideration of both economic and environmental aspects (i.e., 40% increase of hydrogen demand; Before: 142,579,000 US $/year, 109,933.00 tons CO2/year; After: 142,651,000 US $/year, 109,845.00 tons CO2/year).

Influence of basic parameters on the process of pressing of safflower seeds in an ultrasonic field

The influence of pressing conditions on the process nature and the resulting product quality was investigated in the article. This makes it possible to more deeply evaluate and understand the pressing process physics. The objects of research were safflower seeds, safflower oil and oilcake. The objects under study have various physical and technological properties that affect the pressing process, therefore, the study of these properties will help to choose the optimal modes of the pressing process in the ultrasound field, as well as to develop the design of a plant for pressing safflower seeds. To increase the oil yield, one can use the husk when adding it to the bulk of the product. The optimal moisture content range of safflower is 8-10%, which provides the minimum residual oil content and, therefore, the maximum oil yield was determined during the analysis of graphic dependencies. According to the data obtained during the experiment, graphical dependencies were built: on the speed of the screw shaft at the exit of vegetable oil; pressure in the chamber on the size of the annular space for the output of the oilcake. After analyzing the graphical dependencies, one can conclude that an increase in the rotational speed of the screw shaft leads to an increase in temperature, and this happens faster for a product with lower moisture content due to an increase in the friction coefficient of the mixture on the screw and the camera body. A numerical and graphical optimization model for predicting the optimal level of input factors and obtaining the maximum yield of safflower oil in relation to the initial mass of raw materials in% was proposed. The optimal intervals of the input parameters, such as the oscillation frequency, the oscillation amplitude, the pressure generated in the press chamber, were determined in the work..

Design optimization in hard turning of E19 alloy steel by analysing surface roughness, tool vibration and productivity

In the present work, the optimization of machining parameters to achieve the desired technological parameters such as surface roughness, tool radial vibration and material removal rate have been carried out using response surface methodology (RSM). The hard turning of EN19 alloy steel with coated carbide (GC3015) cutting tools was studied. The main problem faced in manufacturer of hard and high precision components is the selection of optimum combination of cutting parameters for achieving required quality of surface finish with maximum production rate. This problem can be solved by development of mathematical model and execution of experiments by RSM. A face centred central composite design (FCCD), which comes under the RSM approach, with cutting parameters (cutting speed, feed rate and depth of cut) was used for statistical analysis. A second-order regression model were developed to correlate the cutting parameters with surface roughness, tool vibration and material removal rate. Consequently, numerical and graphical optimization were performed to obtain the most appropriate cutting parameters to produce the lowest surface roughness with minimal tool vibration and maximum material removal rate using desirability function approach. Finally, confirmation experiments were performed to verify the pertinence of the developed mathematical models.

Starter consortia for on-farm cocoa fermentation and their quality attributes

A starter consortium of Saccharomyces cerevisiae (Y), Lactobacillus plantarum (LAB), and Acetobacter aceti (AAB) was defined to ferment the Cocoa beans (Theobroma cacao). Emphasis was laid to optimize the microbial concentration with a functional ratio of selected cultures. A central composite rotatable design (CCRD) was employed to study the effect of inoculum size (0–20% w/v) with alcohol, titrable acidity, polyphenols, anthocyanin, cut test, and sensory as response variables. The significant (p < 0.05) response surface models with high coefficients of determination values (R2) ranging from 0.82 to 0.93 were considered for the experimental data, which represented the polynomial response models for describing the constraints. Based on the design, the concentration of consortia ranged 9.03X103 CFU/g of Y, 5.9X104 CFU/g of LAB, and 7.0X104 CFU/g of AAB. The graphical optimization of superimposed contour plots fulfilled the desired metabolites; alcohol (Y1) ≤ 11 mg/g, titrable acidity (Y2) ≥ 0.25%, polyphenols (Y3) ≤ 4.0 mg/g, anthocyanin (Y4) ≤ 14 mg/g, sensory (Y5) ≥ 6.0, and cut test (Y6)≥95%. Thus, validation through a field trial was confirmed to adopt the techno-economic feasibility on-farm process with precise inoculums. The effect of starter consortia on Cocoa fermentation and quality was found to be significant.

Implementing Circular Economy in municipal solid waste treatment system using P-graph

Municipal solid waste (MSW) is one of the issues associated with the growth of economic and urban population. The aim of this study is to develop an integrated design of waste management systems in support of a Circular Economy by P-graph (a bipartite graphical optimisation tool) as an effective decision support tool. The case study considers four MSW compositions based on different country income levels. Solving the P-graph model identifies the most suitable treatment approaches, considering the economic balance between the main operating cost, type, yield, quality of products, as well as the GHG emission (externality cost). The identification of near-optimal solutions by P-graph is useful in dealing with the trade-offs between conflicting objectives, e.g. local policy and practical implementation, that are difficult to monetise. For a lower-income country, the optimal solution includes a combination of at source separation, recycling, incineration (heat, electricity), anaerobic digestion (biofuel, digestate) and the landfill. It avoids an estimated 411 kg CO2eq/t of processed MSW and achieves a potential profit of 42 €/t of processed MSW. The optimisation generally favours mechanical biological treatment as the country income level rises, which affects the composition of the MSW. The relative prices of biofuel, electricity and heat (>20%) cause a significant impact on the highest-ranking treatment structure and overall profit. This study shows that the developed framework by P-graph is an effective tool for MSW systems planning. For future study, localised data inputs can be fed into the proposed framework for a customised solution and economic feasibility assessment.

MRI-Guided Brachytherapy PLAN Optimization with Three Versus FOUR Fraction Treatment for Locally Advanced Cervical Cancer

MRI-guided brachytherapy (MRgBT) has become the standard treatment for locally advanced cervical cancer. The ability to optimize target and organ-at-risk (OAR) doses with three-dimensional image-based planning has improved toxicity profiles and local control. MRgBT, however is considerably more resource-intensive than the classical 2D planning and most of the available data on MRgBT has been based on a four fraction protocol of 7 Gy per fraction (7x4). A potential alternative to minimize resource utilization is a three fraction regimen of 8 Gy per fraction (8x3). However, there is limited data on MRgBT using the 8x3 protocol. The ability of this higher dose per fraction treatment to meet EMBRACE II planning aims has not been extensively studied. This study aims to compare optimized 8x3 vs 7x4 plan dosimetry. Ten patients with locally advanced cervical cancer (FIGO IB2 – IVA) treated at a single institution between July 2018 and January 2019 were included in this planning study. Clinical plans that were optimized and treated using a prescription 7x4 and the EMBRACE II planning aims (CTVHR D90% 90-95 Gy, rectum D2cm3 < 65 Gy and bladder D2cm3 < 80 Gy) were retrieved. Plans were then scaled to 8x3 and adjusted using graphical optimization. Three scenarios were evaluated: (1) The CTVHR D90% EQD2 dose was adjusted to be equivalent to the 7x4 plans; while limiting doses to organs at risk. Bladder and rectum D2cm3 doses and GTV D98% doses were recorded. (2) The bladder D2cc EQD2 dose was adjusted to be equivalent to the 7x4 plans (3) The rectal D2cc EQD2 dose was adjusted to be equivalent to the 7x4 plans. An a/b of 10 was used for the tumor bioequivalent dose calculations and an a/b of 3 for the OAR calculations. Doses were compared using Mann-Whitney-Wilcoxon. The median GTVres and CTVHR volumes were 13.42 cc (1.02 – 92.2) and 32.5 cc (10.99 – 120.4). For the 7x4 plans optimized for clinical treatment, median CTVHR D90%, rectum and bladder D2cm3 EQD2 doses were 93.7 Gy (87.4 – 104.4), 58 Gy (51.3 – 83.7) and 77.7 Gy (72.2 – 89.1). For scenario 1, where CTVHR D90% was made equivalent , median rectum and bladder D2cm3 were 58.5 Gy (51.3 – 84.6 ) and 77.1 Gy (73.1 – 90.0), respectively, with no significant differences compared to the 7x4 plans (P=1.0, P=0.85). Median GTVres D98% for 8x3 plans vs 7x4 was 105.1 Gy (84.5 – 150) vs 110.2 Gy (86.4 - 144.4), P = 0.63. When bladder and rectum in 8x3 were set equal to 7x4 plans (scenarios 1 & 2), there was no significant difference in CTVHR D90% doses (P=0.63, P=0.91) or GTVres D98% (P=0.53, P=0.53) . In this study, planning optimization with the 8x3 fraction protocol yields similar EQD2 doses for CTVHR D90%, bladder and rectum D2cm3 when compared with the 7x4 fraction protocol. The EQD2 GTV D98% is marginally lower for 8x3 when compared to 7x4; however, remains clinically acceptable. Further evaluation in a large cohort of patients is underway.

Evaluation of High Rate MBBR to Predict Optimal Design Parameters for Higher Carbon and Subsequent Ammoniacal Nitrogen Removal

The high rate moving bed biofilm reactor (MBBR) processes were designed for wastewater treatment to meet the past effluent discharge norms of biological oxygen demand (BOD) <50 mg/l. However, they are incapable of meeting current effluent discharge norms which consist of BOD <10 mg/l and total nitrogen <10 mg/l. This study analyses the effect and variation of organic loading rate from 1.21 kg to 4.59 kg chemical oxygen demand (COD)/(m3 day) and surface loading rate from 4.9 g to 24 g COD/(m2 day) on a high rate MBBR performance. The results of COD reduction (CODred) and subsequent ammoniacal nitrogen reduction (NH3–Nred) were in the range of 65.4% to 87.8% and 11.8% to 47.2% respectively. The projected graphical optimization defines the design parameters for MBBR and also predicts CODred and subsequent NH3–Nred. By understanding this subsequent NH3–Nred in the MBBR system, future designs for engineering technologies will be aided.

Kinetics of extraction of the silicon, aluminum, and calcium of the basalt from the Daubaba deposit

The article presents the results of the experimental studies of the kinetics of electric smelting of the basalt from the Daubaba deposit, the main components of which are 50.5% SiO2, 19.9% Al2O3, 9.3% CaO, 9.6% Fe2O3 with the extraction of the silicon and aluminum into the ferroalloy, calcium into the calcium carbide. The effect of electric smelting time (from 10 to 60 minutes) and the amount of lime (from 0 to 30% from weight of basalt) on the degree of extraction of Si and Al into the alloy and Ca into CaC2 was determined. The studies were carried out by the method of planning the experiments with the usage of roto-standard plans of second order (Box-Hunter plan) with exploring graphic optimization of technological parameters. The electric smelting was carried out in a graphite crucible. The mass of the furnace-charge in each experiment was 400 g. It was found that: extraction of Si, Al into the alloy, and Ca into the calcium carbide becomes noticeable in the first 10 minutes of the process; in the absence of lime, the maximum degree of extraction of the silicon, aluminum in the alloy and the calcium, respectively, contain 80.8%, 72.2% and 69% in 45 minutes; the presence of lime in the furnace-charge allows you to increase the degree of extraction of the calcium in the calcium carbide to 79.8%, however, at this time, the extraction of the silicon and aluminum decreases. To extract 77.1-86.8% of the silicon, 75-82% of the aluminum in the alloy and 75-79% of the calcium in the calcium carbide, the duration of the electric smelting should be 46-50 minutes and the amount of lime to 6.1% from weight of basalt.

Application of chemometric approach for QbD-Enabled development and validation of an RP-HPLC method for estimation of methotrexate

The present work describes Quality by design (QbD)-oriented development of a reverse phase high performance liquid chromatographic (RP-HPLC) method for quantification of methotrexate (MTX). Initially, for performing HPLC studies with UV detector, an appropriate wavelength was selected using a novel technique of Principal Component Analysis (PCA). Risk assessment study was performed, followed by factor screening study using a fractional factorial design (FFD). Subsequently, factor optimization was conducted using a central composite design (CCD), with flow rate and mobile phase ratio as the critical method parameters (CMPs), and tailing factor (TF), theoretical plate count (TPC) and % assay selected as the critical analytical attributes (CAAs). Polynomial modeling was performed to embark upon an optimal solution, followed by numerical and graphical optimization. Chromatographic separation was conducted using the mobile phase composition of acetonitrile (ACN) and ammonium acetate buffer (10 mM, pH 6) in the ratio of 25:75 v/v, flow rate of 0.8 mL/min, column oven temperature of 40 °C, and UV detection at 257 nm. Further, the analytical method was validated as per ICH Q2(R1) guidelines for linearity, accuracy, precision, sensitivity and robustness, ratifying that all the parameters were within the acceptable limits for quantification of MTX.

Formulation, Optimization, and In vivo Evaluation of Gastroretentive Drug Delivery System of Nifedipine for the Treatment of Preeclampsia.

The study aimed to develop gastroretentive drug delivery system of nifedipine, its optimization, and in vivo evaluation. Bilayered tablet of nifedipine was prepared using central composite design with 3 factors, 5 responses, and 15 experimental trials. Response surface methodology along with numerical and graphical optimization was used to select the best formulation. Scanning electron microscopy study of optimized tablet at different time interval was carried out which showed formation of porous structure on the tablet surface. In vivo studies for optimized formulation were carried out on 10 healthy human volunteers and obtained pharmacokinetic parameters were compared with the marketed formulation, "Nicardia XL." Optimized formulation containing 3.083mg HPMC K15M, 29.859mg HPMC E15LV, and 3.541mg Carbopol 974P releases the drug in a desired manner and remain buoyant for more than 12h in human stomach. Both the formulations were found to have similar in vitro release profile (f1 4.5089 and f2 55.8274) and also were found to be bioequivalent. Finally, the stability study of the optimized formulation proved the integrity of the optimized formulation. Hence, the data suggest gastroretention as a promising approach to enhance bioavailability of nifedipine.

Robust Optimization for Gynecological High-Dose Rate Interstitial BrachytherapyUsing Post-Hoc Uniformity Correction

Graphical optimization (GO) is commonly used during forward planning high-dose rate (HDR) interstitial brachytherapy (IB) to conform prescription dose to high-risk clinical target volume (HRCTV) while limiting organs-at-risk (OAR) doses. However, this typically Results in variations in dwell times between adjacent dwell positions even within an interstitial catheter (Figure 1a). When using IB for locally advanced/recurrent gynecological cancers, a common fractionation approach involves 5 fractions delivered twice daily over 3 days. During this time, day-to-day variations in internal normal tissue anatomy (bowel/bladder filling) can occur. Connecting and disconnecting transfer tubes for each treatment may result in longitudinal movement of individual catheters. Above factors could impact actual dose delivered. To mitigate the impact of these variations, we seek to explore the impact of a post-hoc uniformity correction (PHUC) on the GO plan and report an initial clinical experience with using this robust optimized (RO) approach.

Incidence of operative parameters in the production of biohydrogen generated from urban organic waste

Organic waste is considered a substrate of great interest to produce biohydrogen. In the present work, the influence of some physical and chemical parameters in the operation of a bioreactor for biohydrogen generation were studied, taking as a substrate organic residue from a wholesale food market without adding inoculum. Therefore, an experimental design of central composition was made, with four factors and two levels. The dependent variables were maximum hydrogen content (% of H2), daily production of hydrogen (L H2 d-1) and its cumulative production (L H2). The independent variables were operation pH (pHo), pH of acidification (pHa), the duration time of the acidification stage, and stirring. A numerical optimization was carried out, allowing the prioritization of the factors, and maximizing the response variables. Resulting in a yield of up to 14.9 L H2 d-1, a hydrogen content of 49.2% and a cumulative production of 21.6 L H2, for pHa values of 4.9; pHo between 6 and 6.1; acidification time of 2 d and stirring of 41.4 rpm. Likewise, a graphical optimization was carried out, reaching 14.9 L H2 d-1, a hydrogen content of 44.2% and an accumulated 22.8 L H2, for pHa values between 4.5 and 4.95; pHo between 5.6 and 6.3; acidification time of 2 d, and stirring of 37.1 rpm. Maximum yields were 1.9 L H2 Lwaste.day-1, 4800 mL H2 gCOD-1, and 608.6 mL H2 gTVSadded-1, values similar to those reported by other authors using organic waste in the production of hydrogen, using inoculum.

Nonlinear Comparative Optimization for Biomaterials Wear in Artificial Implant Technology

Today, artificial implants (AI) industry depends strongly on tribological constitution of the material (s) of the implant. Erosion, corrosion, tribocorrosion and biocorrosion are essential factors to determine both functionality and lifetime of the AIs. Histo-Biocompatibility is also an additional constraint, indispensable for implant manufacturing process. The prediction of durability, based on the computational and experimental study of constituents of AI material (s) are key factors to obtain objective data of any AI characteristics. This contribution deals with a computational comparative analysis of materials for hip implants using Archard’s model mainly. Selected hip implant material hardness are Co-Cr alloy and Titanium types. Method is carried out with specific material data, e.g., hardness or wear constants, nonlinear optimization and graphical subroutines. Results presented are both numerical and graphical. Particular interest is focused on application of the 3D Graphical Optimization method.

Formulation, characterization and optimization of nebivolol-loaded sustained release lipospheres

Purpose: To formulate, characterize and optimize nebivolol-loaded sustained release lipospheres (LPs) using beeswax (BW) as the drug carrier. Methods: Nebivolol-loaded LPs were formulated using solvent evaporation technique (SET) and characterized. The impact of independent variables on responses such as percentage yield (PY), entrapment efficiency (EE) and drug release after 12 h (DR12) was assessed using central composite design (CCD). Numerical and graphical optimization techniques were also used to evaluate outcomes of the measured responses. Results: Twenty micron-sized (20 - 100 μm), smooth spherical LPs with good rheological properties were produced. The yield ranged from 33 (F10) to 81 % (F6), while EE ranged from 32 (F4 and F9) to 69 % (F6). The results of rheological evaluation revealed angle of repose > 24 o, Hausner’s ratio > 1.5, and Carr’s index ranging from 13 to 19 %. Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and x-ray diffraction (XRD) revealed nebivolol and BW compatibility, and the absence of possible interactions between formulation components. Duration of nebivolol release was strongly associated with BW concentration and formulation F15 showed minimum drug release (46%). Drug release was significantly higher in formulations with similar BW concentrations and low Tween-20 (T-20) concentrations (F1 and F11) than in formulations with high T-20 concentrations (F2, p < 0.05). The zeta potential of deflocculated LPs ranged from +15 to +35 mV. Nebivolol release (46 - 85 %) at pH 6.8 was significantly affected by BW concentration and it followed zero order model. Conclusion: The results obtained in this study have shown that BW is a suitable material for producing an effective sustained release formulation. The mechanism of drug release in nebivolol- loaded LPs is diffusion accompanied by erosion. Keywords: Lipospheres, Nebivolol, Beeswax, Formulation, Central composite design