Nowadays, advanced oxidation processes are one of the best techniques for the removal of organic matter from an aqueous medium, and they are also used as a disinfection process. TiO2 has been used ...for many pathogenic microorganisms due to its catalytic properties applied in water disinfection processes; however, its recover and reuse is difficult since it is a powder. In this context, diverse materials and methods have been tested to support TiO2. The objective of the present study is to synthesize an economic and environmentally friendly material, with the properties of being efficient in eliminating pathogenic microorganisms such as Escherichia coli (E. coli) and being easy to eliminate from aqueous solutions. Photocatalytic membranes of chitosan and titanium dioxide doped with carbon and nitrogen (Ch/TiO2–C,N) were obtained. To determine the morphology, structure, composition, and optical properties of theTiO2-C,N powder, it was characterized by FE-SEM, XRD, DRUV-Vis, and XPS, and the membranes were characterized by FE-SEM and FT-IR. The antibacterial activity of the membranes was evaluated using Escherichia coli as a model organism under visible light. The Colony Forming Unit (CFU) was calculated for each sample. Chitosan membranes were successfully synthesized with TIO2-C,N and proved to be efficient in the E. coli elimination. It was observed that 93.77 % of the bacterial inactivation after 2 h with the Ch/TiO2–C,N membranes, and a total inactivation after 3 h under visible light. The advantage of this material is that it's efficient and easily recoverable from the aqueous medium. It could also be used as an alternative method to chlorine or as a complementary method in water treatment.
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•Reusable chitosan/TiO2–C,N membranes were obtained that were easy to remove from the aqueous medium.•Chitosan/TiO2–C,N membranes achieved complete elimination of Escherichia coli by photocatalysis.•The Gompertz equation became an effective and alternative method to calculate the band gap of the material.•Chitosan/TiO2–C,N membranes can be used in water disinfection as an alternative method to chlorine.
COVID-19 has crippled the world's healthcare systems, setting back the economy and taking the lives of several people. Although potential vaccines are being tested and supplied around the world, it ...will take a long time to reach every human being, more so with new variants of the virus emerging, enforcing a lockdown-like situation on parts of the world. Thus, there is a dire need for early and accurate detection of COVID-19 to prevent the spread of the disease, even more. The current gold-standard RT-PCR test is only 71% sensitive and is a laborious test to perform, leading to the incapability of conducting the population-wide screening. To this end, in this paper, we propose an automated COVID-19 detection system that uses CT-scan images of the lungs for classifying the same into COVID and Non-COVID cases. The proposed method applies an ensemble strategy that generates fuzzy ranks of the base classification models using the Gompertz function and fuses the decision scores of the base models adaptively to make the final predictions on the test cases. Three transfer learning-based convolutional neural network models are used, namely VGG-11, Wide ResNet-50-2, and Inception v3, to generate the decision scores to be fused by the proposed ensemble model. The framework has been evaluated on two publicly available chest CT scan datasets achieving state-of-the-art performance, justifying the reliability of the model. The relevant source codes related to the present work is available in: GitHub.
Bio-hydrogen production is of significant interest as it is capable of consuming waste material and synthesizing hydrogen which is a green gas. In this study, we examined the dose-dependent effect of ...iron shaving on bio-hydrogen production from an integrated dark and photo fermentation system from an artificial food waste. Overall, introduction of iron shaving enhanced the bio-gas production. Statistical analysis was performed on the extracted parameters obtained from fitting the experimental data to Gompertz function, revealing that the bio-gas production can be significantly enhanced by addition of iron shaving at concentrations up to 500 mg/L, with a maximum enhancement at 200 mg/mL. GC analysis showed that introduction of iron shaving at 200 mg/L also maximized the hydrogen percentage in the produced bio-gas. Based on the HPLC results, it was postulated that the dark-fermentation step was probably the step that was more affected by the introduction of iron shaving. Investigation of the pH showed that the acidification of the solution approximately coincided with the termination of the process. Our finding suggests that a more efficient buffer-assisted setup can significantly enhance the bio-hydrogen efficiency.
•Iron shaving can significantly enhance bio-hydrogen purity and production yield.•The dark-fermentation step is likely to be affected by iron shaving introduction.•Optimal iron shaving concentration may differ for different systems.•Fermentation process could be halted by the acidulation of the solution.
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•Chia plant was more sensitive to salinity during seedling growth stage compared to the germination's one.•During germination, antioxidant enzymes activity increased with increasing salinity up to ...200 mM.•At seedling growth, the highest amount of total phenols and flavonoid was achieved at the 40 mM salinity level.•During seedling growth, the highest amount of soluble sugars, nitrogen and protein was obtained at salinity levels less than 40 mM.•Based on Gompertz model's, salinity reduced germination and seedling establishment and increased the time to reach the maximum value of these traits.
Salvia hispanica (chia), a genus of Lamiaceae is a super food plant, which could be used as an oilseed and industrial medicinal crop in agro-ecosystems. High salinity inhibits chia seed germination and seedling growth, but the plant is moderately tolerant to salt. It is therefore important to study the role of antioxidant enzymes, biologically active compounds, and other eco-physiological responses related to salinity tolerance in this plant. However, despite of many nutritional benefits, there is a lack of information about chia seeds and seedling eco-physiology. Two experiments were conducted based on the completely randomized design in three replications. In the first experiment, salinity tolerance of chia was evaluated using final germination percentage, mean germination time, germination rate, seedling vigor and antioxidant enzymes activity at germination stage at six levels of sodium chloride (NaCl) solutions including (0, 50, 100, 150, 200, 250 mM). In the second experiment, salinity tolerance of chia seedling were evaluated at seven levels of NaCl solutions up to 150 mM (0, 20, 40, 60, 80, 100 and 150 mM). Results revealed that salinity significantly affected all traits except for seedling water content and photosynthetic water use efficiency at the seedling stage. Among seed germination parameters, only mean germination time increased by 77.2% at 200 mM salinity concentrations compared to control. Seed soluble protein increased by 37.50% at 50 mM NaCl and then declined by at 150 mM 46.36%. The activity of catalase and peroxidase increased 125.5% and 99.4% with increasing NaCl concentration from 150 to 200 mM, but malondialdehyde activity decreased 53.9%. It was revealed that secondary metabolites (total phenol and flavonoids) in chia seedlings increased by 55.0% and 9.9% at 40 mM, NaCl concentration while soluble sugars, nitrogen and protein content declined by 73.0, 57.6 and 57.6% at 150 mM compared to control salinity treatment. In addition, salinity had a negative effect on stomatal conductance, photosynthesis and transpiration rate, which are key players in salinity stress tolerance mechanisms of chia seedlings, especially up to 40 mM salt concentrations. Non-linear gompertz function provided an excellent description for chia seed germination (R2adj ≥ 0.97 and RMSE ≤ 4.49) and seedling establishment (R2adj ≥ 0.93 and RMSE ≤ 5.41) under salinity condition. A significant reduction in seed vigor index (40.4%) occurred at 50 mM NaCl concentration. chia seedlings below 40 mM NaCl concentration may encounter less detrimental effect.
•Several logistic functions were tested in order to assess its applicability to wind turbine power curves.•The 6PLE function is the best option to model a wind turbine power curve due to its ...performance.•The 3PLE and 5PLE functions are strongly recommended considering the approximation given and the number of parameters.•Functions as Gompertz, 3PL, 4PL, 5PL and 6PL have to be discarded.
In recent years logistic functions have been used to model wind turbine power curves. Generally speaking, it can be said that the results provided by the logistic functions are good enough to choose them over other options considering its continuity and adaptability. However, there are some logistic functions that have never been used to model wind turbine power curves although their use can be adequate. Comparing all logistic functions can help definitely to decide which are the best options.
In this paper, the most known logistic functions are presented and tested to model wind turbine power curves, included those already used. Moreover, a comparison is made among them, after which two logistic functions are eventually recommended and some other are definitively discarded.
This study examined the effects of relative advances in the ratio of higher mobility roads over higher accessibility roads (MPA) and income inequality on growth of passenger car ownership in relation ...to economic growth. (MPA is calculated by dividing the total length of higher mobility roads tolled expressways, national highways, and other main road networks serving medium- to high-speed traffic by the total length of higher accessibility roads secondary and regional road networks in that country in a specific year.) Specifically, we employed the Gompertz function to model changes in the growth rate of car ownership and the income elasticities. The analysis used a panel data between 1963 and 2013 for 53 countries with various income levels. Results revealed that passenger car ownership rate is consistently higher at most of the per capita income levels under mid-range MPA and lower income inequality conditions. As expected, income elasticities were found varied for groups of countries experiencing different MPA and income inequality conditions under different economic developmental levels. Aside from contributing to the highest passenger car growth, the combined effect of mid-range MPA and lower income inequality conditions was also associated with higher income elasticity at higher per capita GDP. In contrast, countries with extreme MPA under higher income inequality conditions generally have the lowest passenger car growth but highest income elasticity at lower per capita GDP. The implications of these findings on private transportation policies relate to measures to control increased car ownership as well as to reduce road casualties.
To use the Gompertz function to estimate the age and the amount of myopia at stabilization and to evaluate associated factors in the Correction of Myopia Evaluation Trial (COMET) cohort, a large ...ethnically diverse group of myopic children.
The COMET enrolled 469 ethnically diverse children aged 6 to younger than 12 years with spherical equivalent refraction between -1.25 and -4.50 diopters (D). Noncycloplegic refraction was measured semiannually for 4 years and annually thereafter. Right eye data were fit to individual Gompertz functions in participants with at least 6 years of follow-up and at least seven refraction measurements over 11 years. Function parameters were estimated using a nonlinear least squares procedure. Associated factors were evaluated using linear regression.
In total, 426 participants (91%) had valid Gompertz curve fits. The mean (SD) age at myopia stabilization was 15.61 (4.17) years, and the mean (SD) amount of myopia at stabilization was -4.87 (2.01) D. Ethnicity (P < 0.0001) but not sex or the number of myopic parents was associated with the age at stabilization. Ethnicity (P = 0.02) and the number of myopic parents (P = 0.01) but not sex were associated with myopia magnitude at stabilization. At stabilization, African Americans were youngest (mean age, 13.82 years) and had the least myopia (mean, -4.36 D). Participants with two versus no myopic parents had approximately 1.00 D more myopia at stabilization. The age and the amount of myopia at stabilization were correlated (r = -0.60, P < 0.0001).
The Gompertz function provides estimates of the age and the amount of myopia at stabilization in an ethnically diverse cohort. These findings should provide guidance on the time course of myopia and on decisions regarding the type and timing of interventions.
Multimodel frameworks are common in contemporary elasmobranch growth literature. These techniques offer a proposed improvement over individual growth functions by incorporating additional candidate ...models with alternative characteristics. Sigmoid functions (e.g. Gompertz and logistic) are a popular alternative to the commonly used von Bertalanffy growth function (VBGF) as they are hypothesized to better suit certain taxa based on body shape (such as batoids) or reproductive mode (such as egg‐layers). However, this hypothesis has never been tested. This study examined 74 elasmobranch multimodel growth studies by comparing the growth curves of their respective candidate models. Hypotheses regarding model performances were rejected as the VBGF was equally likely to fit best for all taxa and reproductive modes. Subsequently, no individual model was suited to be used a priori. Differences between candidate model fits were greatest at age zero with Gompertz and logistic functions providing estimates that were 15% and 23% larger on average than the VBGF, respectively. However, length‐at‐age estimates of the different models became negligible at older ages. Differences between candidate models were mostly small (≤5%), and the multimodel framework only marginally affected length‐at‐age estimates. However, there were cases where some candidate models provided inappropriate fits that contrasted considerably to the best fitting model. In some of these instances, a single‐model framework could have yielded biologically unrealistic growth estimates. Therefore, no study could pre‐empt whether or not it required a multimodel framework. A framework was subsequently recommended to maximize the accuracy of model fits for elasmobranch length‐at‐age estimates using multimodel approaches.
In order to facilely predict the multicomponent breakthrough curves and avoid the complicated numerical solution, this work proposes two empirical models based on the logistic and Gompertz functions. ...The S-shaped and bell-like curves correspond to the adsorption and displacement processes respectively. The equilibrium loading of each component can be calculated by integration of the measured breakthrough curves. The effects of the model parameters on the breakthrough curves are investigated. The applicability of the two empirical models is validated by three binary and four ternary adsorption systems, including the gas–solid and liquid–solid adsorption. The residual plot and coefficient of determination (R2) are used to evaluate their fitting quality. The results indicate that the fitting curves agree well with the experimental data and all of the residuals are distributed randomly. The five model parameters (k, τ, k*, τ* and c) are easily obtained by the nonlinear regression. For example, the fitting results are k = 1.37 × 10−2 min−1, τ = 292 min, k* = 1.25 × 10−2 min−1, τ* = 453 min and c = 85.3 for adsorption of n-butyl acetate and p-xylene on granular activated carbon. On the whole, the Gompertz model is superior to the logistic model in terms of the fitting accuracy. The significance of this work is to provide a simple and practical method for prediction of the multicomponent breakthrough curves.
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