Adequate Precision Research Articles

Population pharmacokinetic analyses for sulbactam-durlobactam using Phase 1, 2, and 3 data.

Sulbactam-durlobactam is a β-lactam/β-lactamase inhibitor combination approved in the United States for the treatment of hospital-acquired and ventilator-associated bacterial pneumonia caused by susceptible isolates of Acinetobacter baumannii-calcoaceticus in adults. A population pharmacokinetic (PK) model of sulbactam-durlobactam in plasma was developed using data from eight Phase 1-3 studies. A total of 432 subjects and 8,100 plasma concentrations were available for the population PK data set. The combined model was a four-compartment (two compartments per drug) model with linear kinetics. Both renal clearance and nonrenal clearance were estimated, and total clearance was calculated as the sum of renal and nonrenal clearance. Individual renal clearances were scaled by baseline creatinine clearance. The sampling-importance-resampling analysis indicated that the parameters were estimated reliably with adequate precision. Hemodialysis (HD) and epithelial lining fluid (ELF) sub-models were developed for each analyte separately. Intermittent HD resulted in an approximately 30% decrease in the daily area under the concentration-time curve (AUC0-24) when HD was started 1 hour after the end of the infusion. Assuming protein binding estimates of 10% and 38% for durlobactam and sulbactam, respectively, ELF penetration ratios were found to be 41.3% for durlobactam and 86.0% for sulbactam. Of the statistically significant covariates of PK identified, which included body weight, body mass index, infection type, and region of origin, renal function was the only clinically relevant covariate. Overall, a robust description of the plasma PK of sulbactam and durlobactam was achieved. The resultant population PK model was expected to be appropriate for model-based simulations and assessment of pharmacokinetic-pharmacodynamic relationships.

Determination of Hormonal Growth Promotants in Beef Using Liquid Chromatography-Tandem Mass Spectrometry.

Hormonal growth promotants (HGPs) are a class of pharmaceutical agents commonly administered to cattle in the United States to improve growth rates of the animal, alter behavior, or to improve the desired characteristics of retail cuts of meat. There is a concern that low residual concentrations of HGPs may remain in tissue after slaughter, and consumption of tissues containing these compounds may increase the risk of adverse health outcomes, including cancer. Sensitive and selective methods are necessary to assess exposure of HGPs by populations that consume meat products from animals that may have been administered HGPs. A liquid chromatography-tandem mass spectrometry method was developed and validated to detect the low-level presence of HGPs including estradiol, testosterone, estradiol benzoate, melengestrol, melengestrol acetate, progesterone, testosterone propionate, trenbolone, trenbolone acetate, and α-zearalanol in retail cuts of meat following a liquid-liquid extraction using a high pH solution with 30-50× less mass of meat required as compared to similar approaches. Good chromatographic performance and sensitivity was achieved utilizing ammonium fluoride as a mobile phase additive without the need for derivatization. Validation parameters including accuracy, precision, recovery, matrix effects, limits of detection, limits of quantitation, linear range, and stability were determined. The limits of detection ranged from 0.1 to 1.0 ng/g, depending on the compound, with adequate accuracy and precision without the need for extensive sample preparation approaches.

Development and validation of a rapid HPLC-MS/MS method for simultaneous determination of cyclosporine A and tacrolimus in whole blood for routine therapeutic drug monitoring in organ transplantation.

Therapeutic drug monitoring is an integral part of organ transplantation. A rapid, simple, economical, and robust high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for simultaneously determining the immunosuppressants cyclosporine A and tacrolimus might increase detection efficiency. In this study, we developed and validated a rapid HPLC-MS/MS method. Whole blood samples of 100 μL were prepared by protein precipitation with acetonitrile and 0.5mol. L-1 ZnSO4. Chromatography was performed on a pre-column using a gradient elution with 20mmol. L-1 ammonium formate and 0.1% (v/v) formic acid in water (mobile phase A) and 0.1% (v/v) formic acid in methanol (mobile phase B) at a flow rate of 1.5mL.min-1. The analysis time was 2.2min. Electrospray ionization and multiple reaction monitoring were performed. The lower limit of quantification was set at 1ng. L-1 for tacrolimus and 50 ng. L-1 for cyclosporine A. The method showed adequate accuracy and precision with a sufficient linear range. The calibration curve range of tacrolimus and cyclosporine A was 1-30 and 50-1500 ng·mL-1, respectively. All correlation coefficients were >0.99. The developed HPLC-MS/MS is rapid and can be used for simultaneous monitoring of tacrolimus and cyclosporine A.

Hybrid Fiber Reinforcement in HDPE–Concrete: Predictive Analysis of Fresh and Hardened Properties Using Response Surface Methodology

Plastic waste accumulation has driven research into recycling solutions, such as using plastics as partial aggregate substitutes in concrete to meet construction needs, conserve resources, and reduce environmental impact. However, studies reveal that plastic aggregates weaken concrete strength, creating the need for reinforcement methods in plastic-containing concrete. This study used experimental data from 225 tested specimens to develop prediction models for the properties of concrete containing macro-synthetic fibers (MSFs), steel fibers (SFs), and high-density polyethylene (HDPE) plastic as a partial substitute for natural coarse aggregate (NCA) by volume utilizing response surface methodology (RSM). HDPE plastics were used as a partial substitute for NCA by volume at levels of 10%, 30%, and 50%. MSFs were added at levels of 0, 0.25%, 0.5%, and 1% by volume of concrete, while SFs were added at levels of 0, 0.5%, 1%, 1.5%, and 2% by volume of concrete. The input parameters for the models are the ratio of HDPE, the dose of MSF, and the dose of SF. The responses are the slump value, the compressive strength (CS), the splitting tensile strength (TS), and the flexural strength (FS) of concrete. The significance and suitability of the developed models were assessed and validated, and the parameters’ contribution was investigated using analysis of variance (ANOVA) and other statistical tests. Numerical optimization was used to determine the best HDPE, MSF, and SF ratios for optimizing the mechanical properties of concrete. The results demonstrated that replacing NCA with HDPE plastics increased the workability and decreased the strength of concrete. The results demonstrated the applicability of the developed models for predicting the properties of HDPE–concrete containing MSFs and SFs, which agreed well with the data from experiments. The created models have R2 values more than 0.92, adequate precision more than 4, and p-values less than 0.05, showing high correlation levels for prediction. The RSM modeling results indicate that the inclusion of MSFs and SFs improved the mechanical properties of HDPE–concrete. The optimum doses of MSFs and SFs were 0.73% and 0.74%, respectively, of volume of concrete, leading to improvement in the mechanical properties of HDPE–concrete. This approach reduces plastic waste and its detrimental environmental impact. Further development of models is needed to simulate the combined effects of different fiber types, shapes, and dosages on the performance and durability of plastic-containing concrete.

High-resolution chemical patterns from negative tone resists for the integration of extreme ultraviolet patterns of metal-oxide resists with directed self-assembly of block copolymers

Extreme ultraviolet (EUV) lithography faces significant challenges in designing suitable resist materials that can provide adequate precision, while maintaining economically viable throughput. These challenges in resist materials have led to printing failures and high roughness in EUV patterns, compromising the performance of semiconductor devices. Integrating directed self-assembly (DSA) of block copolymers (BCPs) with EUV lithography offers a promising solution because, while the BCPs register to the EUV-defined chemical guiding pattern, the thermodynamically determined structures of the BCPs automatically rectify defects and roughness in the EUV pattern. Despite the superior resolution of metal-oxide EUV resists (MORs), their application to DSA is limited by the difficulty in converting them into chemical patterns that allow effective transfer of the rectified patterns of DSA films into inorganic materials. To address this challenge, this study introduces a novel strategy for fabricating chemical patterns using hydrogen silsesquioxane (HSQ), a high-resolution negative tone inorganic resist, as a model system for MORs. Initially, a sacrificial Cr pattern is generated from HSQ patterns via reactive ion etching. The sacrificial Cr pattern is converted into a chemical pattern by first grafting a water-soluble polyethylene oxide brush onto the substrate, then wet etching the Cr, and finally grafting nonpolar polystyrene brushes. Assembling polystyrene-block-poly(methyl methacrylate) on these patterns results in structures oriented and registered with the underlying pattern, achieving 24 nm full-pitch resolutions. This approach has the potential to integrate MOR patterns into the DSA process, thereby enabling the generation of high-quality sub-10 nm patterns with high-χ BCPs.

Pressurized liquid extraction of sulfite for quantitation by capillary zone electrophoresis.

Sulfite is an additive used in shrimp processing to prevent discoloration. However, sulfite can cause health issues for sensitive consumers, making its monitoring necessary. Determining sulfite concentrations is complex because the Monier-Williams reference method is laborious and has low analytical throughput. Additionally, new techniques are needed to stabilize sulfite during the extraction process because this analyte undergoes rapid oxidation. A new method involving extraction and derivatization of sulfite with formaldehyde through automated pressurized liquid extraction (PLE), followed by quantitation by capillary zone electrophoresis with diode-array detector in indirect mode, was developed and optimized using multivariate planning. The PLE procedure was compared to another solid-liquid extraction method. The new method successfully stabilized and extracted sulfite from shrimp in few steps with adequate precision (CV<3.8%), producing extracts that were stable for 10 days. Recovery was satisfactory (97%-99%), and the limits of detection (4.6mgkg-1) and quantitation (15.4mgkg-1) were suitable for the intended purpose.

A novel bioassay for thyroid-blocking immunoglobulins.

Thyroid-blocking immunoglobulins (TBI) are present in 10%-15% of patients with autoimmune thyroid disease (AITD). TBI affect thyroid function. The analytical performance of a novel TBI bioassay was evaluated. Sera from AITD patients were tested with a cell-based TBI reporter bioassay (Thyretain®) with the expression of a luciferase transgene as readout and a new "Turbo™" TBI bioassay with a readout based on a cyclic AMP-activated luciferase. All samples were also run on two TSH-R binding immunoassays. A Passing-Bablok regression, a Bland-Altman plot, and user/lot comparisons were performed. In addition, dose-response curves for Turbo and Thyretain were fitted using serial dilutions, and half-maximal and 80% inhibitory concentrations (IC50/IC80) were compared. Of 1,011 unselected AITD patients, 131 patients (212 samples) were TBI positive. Of the 212 samples, 149 (70.3%), 47 (22%), and 16 (7.5%) were hypothyroid, euthyroid, and hyperthyroid, respectively. The three thyrotropin receptor antibody (TSH-R-Ab) assays were negative in 90 controls devoid of autoimmune thyroid disorders. In contrast, the Turbo cyclic adenosine 3',5'-monophosphate (cAMP) TBI, Thyretain TBI, and the binding assays detected TBI in 212 (100%), 168 (79%), and 138/180 (65%) samples, respectively (p< 0.001). Turbo highly correlated with thyroid function (p< 0.001). The percentage inhibition in both Turbo and Thyretain correlated with TSH-R-Ab binding assay positivity (both p< 0.001). The two bioassays correlated (r = 0.8, p< 0.001), and the Bland-Altman plot displayed no significant bias (0.24). Values scatter with slight systemic deviation between TBI mean values of 10%-50% inhibition, with higher Turbo than Thyretain results. Intra-assay validation demonstrated adequate precision with a very low coefficient of variation (average CV 5.4%) and lower CV with samples with a high inhibitory effect (CVAverage= 1.7% for a sample with 95% inhibition Thyretain). CV did not differ between users (p = 0.35) and lots (p = 0.121). The IC50/IC80 values were 1.55 ng/mL/3.48 ng/mL for Turbo and 6.76 ng/mL/18.46 ng/mL for Thyretain, respectively, demonstrating the markedly higher sensitivity of Turbo. The novel, easy-to-perform, rapid, and reliable Turbo TSH-R blocking bioassay detected significantly more TBI than the established immunoassays, emphasizing its higher analytical performance and clinical utility in the management of patients with AITD.

Development of a novel crack-resistance technique for concrete slab in the hogging moment region of continuous composite beam

Composite steel-concrete beams offer distinct mechanical advantages. However, concrete cracking in the hogging moment region limits the composite performance of the material. This study presents an innovative technique for enhancing the crack resistance of continuous steel-concrete composite beams, which involves the prestressing of the concrete slab in the hogging moment region through post-tensioning. Following the completion of the concrete slab in the sagging moment region, the prestress is released, thereby preserving pre-compression stress in the hogging moment region without the need for long-term prestressing. This technique is enhanced using uplift-restricted and slip-free connectors, which improve the efficiency of pre-stress introduction. Experimental tests were conducted on composite beams employing this novel technique, alongside numerical simulations. The results indicated that the proposed technique significantly mitigated concrete cracking in the hogging moment region. Specifically, the cracking load of the specimen using the new technique increased by 467 % compared to the traditional composite beam specimen, accompanied by a substantial reduction in both the quantity and width of cracks. Other primary mechanical performance indicators remained relatively similar; however, the new technique exhibited a 14 % increase in the ductility coefficient compared with the traditional method. Additionally, this technique influenced interface slip, moment redistribution, and strain response along the cross-section in both the hogging and sagging moment regions. The numerical results aligned closely with the experimental data, confirming their accuracy and effectiveness. The simulations provided solutions for various construction stages by incorporating different connection constitutive models with adequate precision. A parametric analysis was conducted, revealing a design method for the innovative technique.

Flexible electrodes based on laser-induced graphene as an analytical platform to monitor amoxicillin

Graphene production methods are typically complex and include micromechanical exfoliation, reduction of graphene oxide in the liquid phase, and epitaxial growth. However, a more efficient and rapid alternative is the thermal conversion of polyimide into graphene by laser pyrolysis, offering a simpler and faster approach. Thus, this paper introduces an electrochemical platform based on laser-induced graphene generated from a visible light source to detect amoxicillin. For this purpose, a laboratory-constructed 3D-printer was utilized. In this setup, a visible laser source emitting at 449.2 nm with a maximum power output of 3.5 W was integrated into the extrusion nozzle of a fused deposition modeling 3D-printer to manufacture graphene electrodes from polyimide sheets. Subsequently, a differential pulse voltammetry method was proposed showing an oxidation peak at +0.52 V (vs Ag|AgCl|KCl(sat.)). The sensor exhibited a wide linear working range from 9.60 to 103.3 µmol L−1, a limit of detection of 5.4 μmol L−1, adequate precision (RSD < 7%), and recovery values of 90% to 107% when applied to milk samples, synthetic urine, and pharmaceutical formulations. The sensor is free from interference with other drugs commonly used in human and veterinary medicine. Herein, we report for the first time a robust, scalable, and inexpensive sensor based on a flexible substrate for the detection of amoxicillin in different matrices. It stands as an accessible possibility for routine analysis in clinical and pharmaceutical contexts.

8408 Comparison of Free Thyroxine (fT4) Reference Ranges in Pregnancy: Evaluanting a Novel Equilibrium Dialysis Coupled with Liquid Cromatography Tandem Mass Spectrometry Analytical Method Versus a Standard Routine Immunoassay

Abstract Disclosure: R.M. Biscolla: Employee; Self; Fleury Medicina e Saude. A. Lebkuchen: Employee; Self; Fleury Medicina e Saude. K.H. Cardozo: Employee; Self; Fleury Medicina e Saude. V.M. Carvalho: Employee; Self; Fleury Medicina e Saude. M.T. Justa: Employee; Self; Fleury Medicina e Saude. J.G. Vieira: Owner/Co-Owner; Self; Fleury Medicina e Saude. M.I. Chiamolera: Employee; Self; Fleury Medicina e Saude. There is a difficulty in assessing thyroid function during the gestational period and one of the most important reasons is the changes in TBG during pregnancy, resulting from the increase in estrogen, lead to interference in the dosages of free thyroxine (fT4) measured by commercial competitive immunoassays, posing limitations on the accuracy and sensitivity of existing assessment methods. Therefore, it is necessary to establish specific reference values for each trimester and for the different methods, so the analysis of fT4 results could be more confidently used in clinical practice.Objective: This study aimed to describe a new direct method for measuring free thyroxine (fT4) utilizing equilibrium dialysis (ED) coupled with liquid chromatography tandem mass spectrometry (LC–MS/MS). Additionally, the performance of this method was compared to a commercial immunoassay, and trimester-specific normal reference ranges for fT4 in pregnancy were determined. Methods: We developed a novel ED LC–MS/MS analytical method employing 96-well dialysis plates for measuring fT4 that demonstrated an adequate sensitivity, precision, and linearity. A total of 291 samples from pregnant women were analyzed, the gestational trimester was determined using ultrasound. Additionally, serum fT4 was assessed using an immunoassay with Beckman Coulter kits to compare the two methods. Results: The lower limit of detection (LLOQ), and upper limit of detection (ULOQ) of the new method were respectively calculated to be 0.4 ng/dL and 20.8 ng/dL. The comparison between the two methods showed median FT4 concentrations of 0.7 ng/dL (range, 0.5–1.1 ng/dL) for the immunoassay and 1.1 ng/dL (0.6–2.1 ng/dL) for the ED LC–MS/MS assay (paired t test, p &amp;lt; 0.0001). A significant correlation between methods was observed (Spearman’s r= 0.4898, p &amp;lt; 0.0001). fT4 reference values for ED LC–MS/MS (2.5–97.5 percentiles) were 0.9–1.9 ng/dL, 0.7–1.4 ng/dL, and 0.7–1.5 ng/dL for the first, second, and third trimesters, respectively, whereas median TSH levels were 1.7 mIU/L (0.05–4.0 mIU/L), 1.7 mIU/L (0.44–3.7 mIU/L), and 1.9 mIU/L (0.28–3.5 mIU/L) for the first, second, and third trimesters, respectively.Conclusions: The study with a recent developed LC-MS/MS fT4 method pointed to the differences with an immunoassay method and underscores the importance of establishing trimester- and method- specific normal reference ranges in pregnancy. Presentation: 6/3/2024

Multi-energy calibration and induced plasma optical emission spectrometry (MEC-MIP OES) as an alternative method for the multi-elemental determination of essential elements in cocoa

The challenge of combining MEC-MIP OES arises from the limited number of emission lines available in this analytical technique. For the MEC-MIP OES optimization, the emission line wavelengths, sample dilution, proportion sample:standard for preparing MEC solutions, and nebulizer gas flow rate were studied. Then, the use of multi-energy calibration (MEC) and microwave-induced plasma optical emission spectrometry (MIP OES) was proposed as an alternative method for the determination of essential elements (Ca, K, Mg, Mn, and Na) in cocoa. In the optimized conditions, the method presented adequate analytical performance, with recoveries of 94–104 % and relative standard deviations lower than 5 %, showing adequate precision. The limits of detection (mg kg−1) were 12 for Ca, 2 for K, 3 for Mg, 3 for Mn, and 6 for Na. The proposed method was applied to analyze cocoa samples cultivated in Brazil and Ecuador after acid decomposition. The results were in the range (mg kg−1) of 409–1530 for Ca, 5520-13300 for K, 1460–3210 for Mg, 16–34 for Mn, and 28–61 for Na. Samples cultivated in Ecuador presented higher metal concentrations than the Brazilian samples. The proposed procedure was an easy and reliable approach for determining metals in cocoa samples, enabling multi-elemental determination with a lower cost and simplified calibration to be applied in routine applications.

Aptamer Insights in Targeting and Designing of Therapeutic Drugs.

In the therapy of chronic and dangerous conditions like as cancer, heart disease, neurological illnesses, or retinal angiopathy, we frequently require most effective dosage schedule with adequate precision and sufficient therapeutic potential. Among these entities with the capacity to behave in a target-specific way are aptamers. Usually, they are produced by an iterative screening procedure named “Systemic Evolution of Ligands by Exponential Enrichment (SELEX)” which is used to complicate nucleic acid libraries. For several biological purposes, including targeted treatment, aptamers are potential and could be easily molded into desirable needs and also be tested in a manner that is not very extravagant or pricey. Chemical modification can be employed to enhance their pharmacological actions or prevent enzymatic degradation, hence guaranteeing their chemical integrity and bioavailability in a physiological setting. The recent advancements made in drug targeting and design with the use of aptamers are the main topic of this review. This review will highlight current developments and go over prospects and problems in the fields of aptamer-based targeted therapy, including aptamer therapeutics.

Optimisation of cooling performance and water consumption of a solid desiccant-assisted indirect evaporative cooling system using response surface methodology

Solid desiccant-assisted dew-point indirect evaporative cooling (SD-DPIEC) systems have gained considerable attention as a potential eco-friendly alternative to vapour-compression cooling systems in building cooling applications. However, one major drawback of these systems is their substantial water consumption during evaporative cooling. To tackle this issue, this study aims to improve the cooling efficiency and water utilisation of an SD-DPIEC system using response surface methodology (RSM). This research focuses on optimising four key parameters: supply air temperature, humidity ratio, water consumption rate and coefficient of performance (COP). The independent variables encompass the ambient temperature, relative humidity, regeneration temperature, and recirculation air ratio. Employing a multi-objective optimisation approach via the desirability function, the optimised SD-DPIEC system is subsequently tested in two prevalent weather patterns in Australia. The results demonstrated that the regression models derived from RSM exhibited commendable predictive capability, with the determination coefficient R2 and Adequate Precision exceeding 0.97 and 40.46, respectively. The outcomes revealed that the system attained its optimal performance with a supply air temperature of 20.36 °C, humidity ratio of 12.56 g kg-1, a water consumption rate of 3.11 kg/hr, and COP of 2.03 under the ambient temperature of 33.79 °C, relative humidity of 68.48 %, regeneration temperature of 51.78 °C, and recirculation air ratio of 60 %. Based on the optimisation results, a case study was undertaken to evaluate the system's applicability in representative Australian climates. The results demonstrated that the system could uphold air conditions with the supply air temperature below 19 °C and humidity ratio below 11.51 g kg-1 under the studied Australian climates.

Rapid Detection of Aflatoxins in Ground Maize Using Near Infrared Spectroscopy.

Aflatoxins are carcinogenic mycotoxins that may contaminate many crops and more especially maize. To protect consumers from these contaminants, many countries set up low regulatory thresholds of few µg/kg. The control of food requires time-consuming analysis for which sampling is a key step. It would therefore of key sanitary and economic relevance to develop rapid, sensitive and accurate methods that could even be applied on line at harvest, to identify batches to be excluded as soon as possible. In this study, we analyzed more than 500 maize samples taken at harvest during 3 years for their aflatoxin contamination using HPLC-MS. Among them, only 7% were contaminated but sometimes at levels largely exceeding European regulations. We demonstrate that Near InfraRed Spectroscopy (NIRS) could be of great help to classify cereal samples according to their level of aflatoxin contamination (below or higher than E.U. regulation). To build the model, all AF contaminated samples as well as an equivalent number of AF free samples were used. NIRS performance was not sufficient to quantify the toxins with adequate precision. However, its ability to discriminate naturally contaminated maize samples according to their level of contamination with aflatoxins in relation to European regulations using a quadratic PCA-DA model was excellent. Accuracy of the model was 97.4% for aflatoxin B1 and 100% for total aflatoxins.

Finite-time adaptive fuzzy event-triggered control for nonlinear time-delay system with input quantization via command filter

This paper investigates the problem of finite-time adaptive fuzzy event-triggered control for a class of uncertain nonlinear systems with input quantization. The nonlinear systems under consideration contain unmodeled dynamics and time-varying delays. Fuzzy logic systems are used to handle unknown nonlinear terms. Additionally, finite-time filters are introduced to solve the problem of “explosion of complexity” as well as to ensure that the derivative of the virtual controller can be approximated in finite time. The Lyapunov–Krasovskii function is used to handle time-varying delays. The hysteresis quantizer is used to ensure adequate precision when there is a low transmission rate requirement. The control strategy combines event-triggered mechanisms and quantization technology to ensure that all signals of the closed-loop system remain bounded in finite time. Finally, two examples are included to demonstrate the effectiveness of the proposed controller.

Statistical analysis of low-density and high-density polyethylene modified asphalt mixes using the response surface method

The common use of plastics in daily life has engendered gigantic amounts of waste plastics, which have a detrimental influence on the environment. Researchers have proposed several strategies for the recycling of waste plastics and their products. Among these, one strategy is to use them in the construction industry, particularly in asphaltic pavements. This study thus focused on the utilization of waste plastics, specifically Low-Density Polyethylene (LDPE) and High-Density Polyethylene (HDPE), as an additive in Asphalt Concrete (AC) mixes. Indirect Tensile Strength (ITS), Flow Time (FT), and Dynamic Modulus (DM) tests were used to investigate the moisture damage, permanent deformation, fatigue performance, and DM of the LDPE and HDPE modified AC mixes. According to the laboratory test results, the LDPE and HDPE modified AC mixes offer more resistance to moisture damage compared to the Control AC mixes. It was also concluded that asphalt mixes modified with the LDPE and HDPE attained 2.07 times and 1.26 times superior resistance to permanent deformation than the Control mixes. Furthermore, the LDPE and HDPE modified AC mixes outperformed the DM values of the Control mixes by 2.06 times and 1.41 times, respectively. In addition, it was determined that the LDPE and HDPE modified AC mixes exhibit 1.72 times and 1.39 times greater fatigue parameter values than their counterpart, suggesting superior fatigue resistance performance. The statistical models developed using Response Surface Methodology (RSM) revealed the highest values of the Coefficient of Determination (>0.80), adequate precision (>4.0), and lack-of-fit tests, indicating the model’s adequacy for predicting the response.

Modeling and design optimization of the performance of stone matrix asphalt mixtures containing low-density polyethylene and waste engine oil using the response surface methodology

In recent years, the use of waste plastic materials such as low-density polyethylene (LDPE) to modify asphalt binders and enhance mixture performance has garnered significant attention. One major concern with using such materials is the higher production temperature required, which necessitates the use of a bitumen extender agent, such as waste engine oil (WEO), to reduce the viscosity and mixing temperature. Therefore, using these stabilizing additives can reduce the consumption of virgin binder, especially for Stone Matrix Asphalt (SMA) mixtures, which require higher asphalt content. This study aimed to optimize the design of SMA modified by LDPE and WEO to minimize the optimum asphalt content (OAC) and mixing temperature while maximizing SMA performance. To achieve this, Response Surface Methodology (RSM) was utilized to develop the necessary models for optimizing design and predicting performance. The selected independent variables (factors) for the design include LDPE content, WEO content, OAC, and mixing temperature. Meanwhile, the responses (dependent variables) consist of Marshall stability, rut depth, tensile strength ratio, and resilient modulus, which were used to determine the best mix design. The findings demonstrated that the suggested models for the output variables can predict performance with a higher level of confidence. The Analysis of variance (ANOVA) demonstrated that predictive models were significant and well-fitted, with a coefficient of determination (R2) of higher than 0.80, an adequate precision value of greater than 4, and a low p-value (less than 0.05). The error percentage between the RSM-predicted and actual values was less than 5 %, indicating that RSM-established models can accurately and efficiently predict the SMA performance. The best mix design of the SMA mixture modified by LDPE and WEO was found to be 10 % LDPE, 3.91 % WEO, 5.92 % OAC, and mixing temperature of 152.24°C with a combined desirability of 82.8 %.

Quantitative Measurement of Multiple Elements in Micro‐Quantities of Crude Oil Using In Situ Analysis by Laser Ablation‐ICP‐MS

Multi‐element quantification in small amounts of material and in situ measurements at the micrometre scale are essential aspects of geological sample investigation. A direct and rapid simultaneous multi‐elemental determination of metals in crude oil samples was carried out by combining direct laser ablation of the oil inserted in silica capillaries with inductively coupled plasma‐mass spectrometry. The accuracy of LA‐ICP‐MS determination was demonstrated by analysing CONOSTAN reference material oils, certified for multiple elements, and by comparing LA‐ICP‐MS measurement results with those obtained by ICP‐OES using microwave‐assisted sample digestion. The results obtained by both methods were in agreement with certified values. The LA‐ICP‐MS method showed an adequate precision with a mean relative standard deviation of less than 10% for multi‐element determination, and was sufficiently sensitive to determine the majority of elements. LA‐ICP‐MS was also applied to the determination of elements in crude oils of different origins. LA‐ICP‐MS is a good alternative method allowing the determination of elements in organic fluids (oil and bitumen) in shorter times, involving less material consumption, smaller test portion size and with higher throughput compared with protocols using, for instance, sample digestion. It validates the possible application of metal analysis in hydrocarbon‐containing fluid inclusions for metallogenic purposes.

Prediction of Bioactive Compounds and Antioxidant Activity in Bananas during Ripening Using Non-Destructive Parameters as Input Data.

Vegetable quality parameters are established according to standards primarily based on visual characteristics. Although knowledge of biochemical changes in the secondary metabolism of plants throughout development is essential to guide decision-making about consumption, harvesting and processing, these determinations involve the use of reagents, specific equipment and sophisticated techniques, making them slow and costly. However, when non-destructive methods are employed to predict such determinations, a greater number of samples can be tested with adequate precision. Therefore, the aim of this work was to establish an association capable of modeling between non-destructive-physical and colorimetric aspects (predictive variables)-and destructive determinations-bioactive compounds and antioxidant activity (variables to be predicted), quantified spectrophotometrically and by HPLC in 'Nanicão' bananas during ripening. It was verified that to predict some parameters such as flavonoids, a regression equation using predictive parameters indicated the importance of R2, which varied from 83.43 to 98.25%, showing that some non-destructive parameters can be highly efficient as predictors.

Investigation on varied sewage sludge producer gas and methane blend equivalence ratios operated SI engine intact with Miller cycle strategy

Decentralised power generation through a gasifier-engine genset can reduce both reliance on power grid and pollution. However, the low calorific value of the produced gaseous fuel moderates engine power and efficiency, which is a big challenge for its utilisation. For early and cost-effective solution prediction, a simulation tool of adequate precision can effectively envisage dual-fuel (DF) mode engine performance. Thus, this study simulates DF-SI engines with late inlet valve closures (LIVCs) to improve thermal efficiency using the Miller cycle strategy. Simulation is performed using quasi-dimensional thermodynamic modelling (QDTM). After validating the model using referred experimental results, QDTM was employed to study the parametric impacts of inputs (blends, LIVC and equivalence ratio) variations on performance and emissions response parameters. Power improves by blending sewage sludge-based producer gas with methane. Multi-objective optimisation through the response surface method (RSM) determined the optimum operating parameters as 0.814 equivalence ratio, 68.23% SSPG-blend and 55.9° CA (ABDC) LIVC. Corresponding optimal responses were 5.906 bar IMEP, 3.85 kW BP, 28.6% BTE, 12.596 MJ/kWh BSEC, 0.134 V% CO and 2045.29 ppm NO emissions. ANOVA-based optimal results presented a composite desirability of 0.843 with a 95% confidence level. Conclusively, methane mix and LIVC approach increase the power and efficiency of the DF-SI engine; additionally, optimisation guides to balance power and emission trade-off.