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• The study investigates the effect of incorporating creative pedagogy within problem-based learning (PBL) sessions on the development of higher-order thinking skills (HOTS) in natural science education. • The findings reveal a significant enhancement in the proficiency of higher-order thinking skills among students who underwent the integration of creative pedagogy within the PBL model. • The study investigates the integration particularly fostering critical analysis, evaluation, and innovative problem-solving abilities. • The integration of creative pedagogy encourages students to transcend conventional knowledge and apply critical thinking in authentic real-world scenarios, allowing them to identify problem origins, evaluate alternatives, and generate creative solutions. • The implications underscore a paradigm shift in learning approaches that has the potential to significantly enrich students' learning experiences in natural science education. This study aimed to assess the impact of incorporating creative pedagogy within a Problem-Based Learning (PBL) on the development of higher-order thinking skills (HOTS) in the field of natural science. A sample of 280 eighth-grade students from a province in Lampung participated in the study. Employing a quasi-experiment design, one experimental group underwent the integration of creative pedagogy within the PBL model, while two control groups did not receive this treatment. The findings from the experiment strongly suggest that the integration of creative pedagogy in PBL sessions significantly enhances the proficiency of higher-order thinking skills within the context of natural science education. Specifically, this integration fosters the students' capacity to critically analyze, evaluate, and devise innovative solutions for intricate problems. By integrating creative pedagogy, students were encouraged to transcend conventional knowledge and apply their critical thinking in authentic real-world scenarios. Notably, students demonstrated not only the capability to pinpoint problem origins but also exhibited prowess in evaluating diverse alternatives, considering consequences, generating creative and workable solutions. However, it is essential to acknowledge the existence of challenges and resistance encountered by both educators and students when implementing creative pedagogy in PBL activities. The implications of integrating creative pedagogy within the PBL model in natural science education underscore a paradigm shift in the learning approach, which has the potential to significantly enrich students' learning experiences. [ABSTRACT FROM AUTHOR]

LiFePO 4 /Very-few-layer-graphene (LFP/VFLG) composites have been prepared using the sol-gel method for lithium-ion battery cathode. VFLG dominated by 1∼3 layers was obtained from an economical and environmentally benign process. Structural properties of LFP/VFLG composites were studied using Fourier-transform infrared spectra (FTIR) spectroscopy, X-ray diffractometry (XRD), high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy, while the electrochemical performance was measured using galvanostatic discharge, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) tests. The FTIR analysis confirmed that incorporating VFLG neither affected the chemical structure of LiFePO 4 nor initiated any side reactions during the LiFePO 4 formation reaction. The XRD results showed that LFP/VFLG composites had better lattice parameters, crystallinity, and phase purity than LiFePO 4 without VFLG addition. The Raman spectroscopy analysis indicated that LFP/VFLG composites had a lower disorder in the carbon arrangement. HRTEM results indicated that a VFLG was successfully wrapped around the LFP particle offers a versatile way to enhanced electrochemical performance of LFP/VFLG composites. The galvanostatic discharge profiles showed an enhancing specific discharge capacity of up to 58.3% after incorporating VFLG. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests revealed that LFP/VFLG delivered small polarization, low inner resistance, high electrochemical reaction reversibility, and high lithium-ion diffusion coefficient. VFLG is a promising additive to improve the structural and electrochemical properties of the LiFePO 4 cathode of lithium-ion batteries. [ABSTRACT FROM AUTHOR]

In diphtheria laboratory examinations, the PCR test can be applied to isolates and clinical specimens. This study aimed to develop a PCR assay to identify the species and toxigenicity of diphtheria-causing bacteria, including the prediction of some NTTB types. Seven reference isolates, four synthetic DNA samples, 36 stored isolates, and 487 clinical samples used for PCR optimization. The PCR results was confirmed by DNA sequence analysis. The results of the PCR examination of the 7 reference isolates and 36 stored isolates were similar to the results obtained using conventional methods as gold standard, both for diphtheria-causing and non-diphtheria-causing bacteria. The validation of the PCR results using DNA sequence analysis showed that there was no mispriming or misamplification. The multiplex PCR assay developed in this study could correctly identify the species and toxigenicity of diphtheria-causing bacteria, including the prediction of some NTTB types not yet covered by established PCR methods. • PCR has limitations in identifying the toxicity of diphtheria-causing bacteria. • Bacterial toxicity was identified phenotypically by the Elek test. • The characteristic of NTTB type is PCR positive tox gene but negative Elek test. • New PCR method to predict several types of NTTB. [ABSTRACT FROM AUTHOR]

• Two-Phase model was developed to simulate the performance of E. aerogenes. • Degree of inhibition (n) described the change on cell's performance. • Methanol concentration in crude glycerol had an influence on critical glycerol concentration. • Glycerol concentration of 22 g/L containing 3.5 g/L methanol gave the highest ethanol production. The application of biodiesel derived crude glycerol for ethanol production using Enterobacter aerogenes TISTR 1468 involved multiple interactions among substrate (glycerol), impurities (methanol) and product (ethanol and acetic acid). A mathematical model based on Monod and Luedeking-Piret models were established to simulate the cell performance in the presence of inhibitors. The Monod model was modified by adding the inhibition factors in terms of critical concentration (C* Ac < C* EtOH < C* MeOH < C* Gly) and its inhibition degree (ni) (n Gly >n MeOH >n Ac >n EtOH with the values of 119.06, 13.33, 1 and 0.0383, respectively). The Luedeking-Piret model confirmed that ethanol and acetic acid were predominantly growth-associated products. Glycerol up to 24.31 g/L and 31.32 g/L were optimum for cell growth and ethanol productivity, respectively. The cell performance was affected by methanol even at its lowest concentration tested (7.92 g/L). The applicability of the new two-phase growth model during the growth phase and stationary phase in the crude glycerol medium was validated and proved accurate (r2> 0.98). [ABSTRACT FROM AUTHOR]

Ethanol production from crude glycerol under microaerobic condition was optimized. The aeration rate in the reactor was controlled using redox potential (ORP) as to replace a conventional oxygen sensor that became insensitive at low oxygen concentration. The performance of Enterobacter aerogenes TISTR1468 in a batch reactor using a simple medium (crude glycerol and tuna condensate (GT) medium) was evaluated on various aeration strategies: continuous aeration at 0.5 vvm; controlled aeration at −350 mV and −400 mV ORP; and no aeration. The 72-h batch fermentation showed that a more reductive environment (lower aeration and ORP value) increased ethanol concentration and yield, but decreased the ethanol productivity. No-aeration fermentation with the lowest ORP value achieved the highest ethanol production (18.78 g L−1) and yield (0.94 g-ethanol.g-glycerol−1). A more oxidative environment (higher aeration and ORP value) fasten the specific growth rate (μ), but ethanol concentration and yield decreased. The optimum specific ethanol production rate (q p) and glycerol consumption rate occurred at ORP of −400 mV and −350 mV, respectively. When the ORP was very low, the μ decreased following substrate depletion, but this phenomenon was not observed at higher ORP value, an evident that adequate oxygen supply could maintain cell viability.Fed-batch with two-stage aeration strategy (−350 mV and −400 mV ORP) acquired higher ethanol production (30.31 g L−1) than fed-batch with single-stage aeration (25.95 g L−1) and batch process (12.33 g L−1).This study has revived the potential of crude glycerol biotransformation to ethanol and opened up opportunities for optimization of related microaerobic systems other than ethanol. • Innovative fed-batch cultivation with two-stage ORP controlled aeration system was developed. • E. aerogenes efficiently convert crude glycerol to ethanol under microaerobic fermentation. • Lower ORP exhibited higher ethanol production while higher ORP improved the specific growth rate. • Fed-batch fermentation (FBF) could double ethanol production compared to batch process (12 g/L). • FBF with two stage aeration controlled by ORP further increased ethanol production to 30 g/L. [ABSTRACT FROM AUTHOR]

• Crude glycerol and tuna condensate (GT) could replace the complex medium for ethanol production. • Addition of inorganic salts and trace elements exhibited similar results with the use of phosphate buffer. • Maintaining pH at 7 using 3 N NaOH gave the same result as adding phosphate buffer. • The optimum condition was 20 g/L glycerol at C/N ratio of 10:1 in GT medium and pH control at 7.0. • The ethanol production increased 2 folds with higher yield than theory and ethanol was produced predominantly. In this work, waste-based raw materials; crude glycerol from biodiesel plant and tuna condensate from tuna canning factory, were used to substitute the expensive complex medium for ethanol production from Enterobacter aeroegenes TISTR 1468. The optimum crude glycerol concentration was 21.43 g/L (˜20 g/L), giving 6.72 g/L ethanol. Using tuna condensate as a nitrogen source for studying the effect of initial C/N ratio (115–365 g/g) revealed the insignificant difference on ethanol production in every C/N ratio tested with a noticeable increase of byproducts (2,3-butanediols) at the high C/N ratio. The addition of inorganic salts and trace element into crude glycerol-tuna condensate (GT) medium resulted in 2-fold increase of ethanol production (12.73 g/L), complete substrate consumption and reduced the formation of byproducts. Optimization studies based on Plackett-Burman design indicated that the most influential parameter amongst the inorganic salt components was phosphate buffer with 77.6% contribution. However, phosphate buffer could be replaced by keeping the pH constant at 7.0 using 3 N NaOH. Under the optimum condition; 20 g/L crude glycerol, initial C/N ratio of 115 g/g and the pH maintained at 7, the ethanol production was 12.33 g/L with 24% higher than the theoretical yield. The selectivity of ethanol production increased upto 3-fold larger than the expensive complex medium. [ABSTRACT FROM AUTHOR]