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Students' sense of belonging impacts their affect, motivation, well-being, and academic success. Sense of belonging is considered context-dependent as what determines one's belonging differs across contexts. This study explores how sense of belonging manifests among post-secondary, introductory chemistry students. This context is important given the threats to belonging that may arise from the transition into post-secondary studies and the pivotal role introductory courses play in student success. To carry out this investigation, 19 post-secondary students from introductory chemistry courses were interviewed following a semi-structured approach. Qualitative analyses were conducted that led to a conceptualization of belonging. Belonging can be situational, dependent on the occurrences within the setting, or dispositional, representing long-standing tendencies. It is also acceptance-based, such as friendships and support, or value-based, where contributions are recognized or acted upon. These traits are combined into four dimensions: Situational Acceptance, Dispositional Acceptance, Situational Value, and Dispositional Value. This nuanced understanding can guide instructional and research efforts to improve students' sense of belonging.

A laboratory experiment that exposes students to fundamental concepts in kinetics and statistical thermodynamics to study systems of great current interest in nanotechnology by employing a foundational technique in physical chemistry is described. A modified commercial flash photolysis spectrometer was used to study photoinduced isomerization reactions on the millisecond time scale for several hydroxy-substituted azobenzene compounds. The temperature-dependent transient decays were analyzed with an Eyring plot to yield the enthalpy and entropy of activation of the reverse isomerization process. The specific compounds studied were 4-phenylazophenol, 4-methyl-2-(phenylazo)phenol, and 2,4-dihydroxyazobenzene in ethanol solvent. Instrumental modifications include substitution of a UV-LED for the probe light source and use of a thin polyimide film heater adhered to the side of the sample cuvette to control temperature. Collection of experimental data and the subsequent plotting and analysis are easily accomplished by upper-division chemistry students and the results are consistently good, comparing well with literature values.

Abstract The sebum on human skin is generated for various causes. The composition of the formed sebum increases the proliferation of Cutibacterium acnes (C. acnes) residing on the skin. As C. acnes proliferates, it produces skin irritants that stimulate the sebaceous glands, increasing sebum production. Skin troubles such as acne may occur. The lysate concentrates of Bacillus stratosphericus (B. stratosphericus), first discovered in the stratosphere, confirmed a 66.35% inhibition of Nitric Oxide (NO) production at 0.50 mg/ml concentration in vitro. Additionally, the growth inhibition efficacy of B. stratosphericus lysate concentrate (BSLC) against C. acnes was confirmed, showing a 95.1% inhibition of growth proliferation at a consistency of 0.50 mg/ml. Based on the in vitro results, the efficacy of BSLC in degrading and reducing sebum was confirmed by reacting it with artificial sebum to various concentrations. The results showed a concentration-dependent decrease in artificial sebum ccording to the efficacy results confirmed in vitro, a clinical trial was conducted to evaluate the daily sebum reduction efficacy of a serum formulation containing 50 mg/ml of BSLC. After a 4-week application, the test group containing BSLC determined a significant 28.68% reduction in sebum levels, demonstrating the practical implications of the research. In conclusion, BSLC is considered to have sufficient industrial value as a valuable ingredient for the cosmetics industry aimed at sebum improvement.

Climate change is a critical scientific and social issue of our time, yet the topic is not frequently discussed by the general public. Additionally, misconceptions about the topic persist. One important aspect of climate change is the greenhouse effect. This activity adds a greenhouse gas discussion to an existing module about molecular shape and modeling. The module links the greenhouse effect to climate change. The activity has been used in several introductory chemistry settings. A discussion of student-generated answers and student-reported learning gains is presented.

The development of equitable grading systems that provide students with effective feedback and provide instructors with an efficient means of assessment are of deep interest to chemical educators. A recent trend in chemical education, and STEM education more broadly, has been the use of specifications, or specs, grading that emphasizes mastery of material through recursive methods and standards-based grading. Students must meet certain standards in multiple specifications to earn a particular letter grade, as opposed to more traditional points-based grading systems. However, changing from a points-based grading system to specs grading requires significant effort by the instructor, especially in courses with an integrated lab component. In this manuscript we describe the development of a hybrid-specs grading system implemented in our second semester general chemistry course over the 2021-22 academic year. We describe the development of the hybrid-specs grading system, student performance as measured by shifts in letter grade distributions and final exam scores, and student perceptions of the new grading system. Notes for practitioners on the implementation of the grading system are in the Supporting Information. Finally, we also discuss improvements of the system for implementation in future courses.

The eChem project features an e-book published as a web page (10.30746/978-91-988114-0-7), collecting a repository of Jupyter notebooks developed for the dual purpose of explaining and exploring the theory underlying computational chemistry in a highly interactive manner as well as providing a tutorial-based presentation of the complex workflows needed to simulate embedded molecular systems of real biochemical and/or technical interest. For students ranging from beginners to advanced users, the eChem book is well suited for self-directed learning, but workshops led by experienced instructors and targeting student bodies with specific needs and interests can readily be formed from its components. This has been done by using eChem as the base for a workshop directed toward graduate students learning the theory and practices of quantum chemistry, resulting in very positive assessment of the interactive nature of this framework. The members of the eChem team are engaged in both education and research, and as a mirroring activity, we develop the open-source software upon which this e-book is predominantly based. The overarching vision and goal of our work is to provide a science- and education-enabling software platform for quantum molecular modeling on contemporary and future high-performance computing systems, and to document the resulting development and workflows in the eChem book.

Worldwide, significant efforts are made to identify energy sources that can help achieve carbon neutrality and promote sustainable development. The development of a catalyst that combines durability and high performance is essential for the commercialization of proton‐exchange membrane fuel cells (PEMFCs). In a fuel cell, carbon corrosion occurs during startup and shutdown due to improper local flooding caused by inadequate water management. In this study, a Pt‐based catalyst is designed with excellent durability and high activity. Introducing a metal oxide layer modified with Pt/multi‐walled carbon nanotubes reduces the direct contact between carbon and the fuel cell environment. This helps prevent carbon corrosion and inhibits the separation, aggregation, and growth of Pt nanoparticles. Moreover, the catalyst exhibits enhanced oxygen reduction activity due to the electronic effect of the metal oxide layer that is coated on it. In this study, by implementing a carbon erosion acceleration protocol, excellent catalytic properties during a load‐cycling experiment consisting of 5,000 cycles are reported. The practical application of the developed catalyst in PEMFCs offers an effective approach to developing Pt‐group metal catalysts with exceptional activity.

This exploratory, mixed-methods study examines first-year general chemistry students' written responses on a belonging survey. Responses were thematically analyzed to identify students' sources of belonging, which may help instructors choose effective strategies for enhancing belonging during the transition into college. Qualitative analysis generated a codebook containing 21 codes from 6 categories: Course Attributes, Interest, Perceptions, Social, Student Attributes, and Value. The qualitative coding data were transformed into quantitative frequency data, allowing identification of the most frequent themes across all participants on each of four surveys: early- and late-semester General Chemistry 1 and 2. Additional analyses explored how belonging explanations varied based on student characteristics that might influence their experience of this large introductory STEM course at a selective, high-income, predominantly White institution. Unique sources of belonging were expected to emerge for groups marginalized in STEM (i.e., Black and Hispanic students, women) and groups who might feel discouraged by a selective institutional and course culture (i.e., students with no credit-bearing AP scores, low course grades, or high belonging uncertainty). Results indicate the importance of interest for all participants' course-level belonging. Students' career goals, perceptions of the course content, and social dynamics with peers also proved universally influential. Some patterns were especially pronounced for marginalized or discouraged groups, who were disproportionately likely to discuss social comparisons and interactions, self-evaluate, and describe the utility-value of the course. These groups were also less likely to express positive cognitive and affective engagement in the course. Implications for supporting student belonging throughout the course sequence are discussed.

The growing need for lithium-ion batteries, fueled by the widespread use of electric vehicles (EVs) and portable electronic devices, requires high energy density and safety. The cathode material Li1-x(NiyCozMn1-y-z)O2 (NCM) shows promise, but attaining high efficiency necessitates optimization of both composition and manufacturing methods. Polycrystalline LiNiCoMnO2 powders were synthesized and assessed in this investigation using a polyvinyl alcohol (PVA) solution method. The study examined different synthesis conditions, such as the PVA to metal ions ratio and the molecular weight of PVA, to assess their influence on powder characteristics. Electrochemical analysis indicated that cathode materials synthesized with a relatively high quantity of PVA with a molecular weight of 98,000 exhibited the highest discharge capacity of 170.34 mAh/g and a high lithium-ion diffusion coefficient of 1.19 × 10−9 cm2/s. Moreover, decreasing the PVA content, irrespective of its molecular weight, led to the production of powders with reduced surface areas and increased pore sizes. The adjustments of PVA during synthesis resulted in pre-sintering observed during the synthesis process, which had an impact on the long-term stability of batteries. The electrodes produced from the synthesized powders had a positive impact on the insertion and extraction of Li+ ions, thereby improving the electrochemical performance of the batteries. This study reveals that cathode materials synthesized with a high quantity of PVA with a molecular weight of 98,000 exhibited the highest discharge capacity of 170.34 mAh/g and a high lithium-ion diffusion coefficient of 1.19 × 10−9 cm2/s. The findings underscore the significance of optimizing methods for synthesizing PVA-based materials to enhance the electrochemical properties of NCM cathode materials, contributing to the advancement of lithium-ion battery technology. The findings underscore the significance of optimizing methods for synthesizing PVA-based materials and their influence on the electrochemical properties of NCM cathode materials. This contributes to the continuous progress in lithium-ion battery technology.

This study seeks to examine the effectiveness of peer-led team learning (PLTL) pedagogy when it is implemented in an entirely online environment. Past evaluations of PLTL have demonstrated the effectiveness of this approach when used with in-person teaching, but an online environment is expected to pose unique challenges to students, and therefore, the past work may not generalize to an online environment. The study implemented PLTL within four classes of second-semester general chemistry each offered online. The classes were evaluated in reference to six classes of the same course, also taught exclusively online, that relied primarily on didactic instruction. The evaluation showed the average score for students with online PLTL ranged from 0.15 to 0.20 standard deviations better than students with online didactic across the tests and final exams and that this difference was partially explained by past performance. Further, online PLTL students had a higher likelihood of earning a passing grade in the class which corresponded with a lower proportion of students failing and a lower proportion of students withdrawing from the course. The results indicate that PLTL was an effective instructional technique within an online modality at the research setting.

The unplanned shift to online instruction due to the COVID-19 pandemic challenged many instructors teaching large-enrollment courses to design learning environments that actively engaged all students. We looked at how one instructor used her instructional team--a group of student assistants with diverse, structured responsibilities--to adapt her large-enrollment (>500 students) introductory chemistry course to a live-remote format, as well as the impact the team's involvement had on students' reported experiences of online learning. We found that the instructional team's involvement was instrumental in adapting the course to the live-remote online format. The integration of the instructional team had a significant positive impact on students' experiences in the course, including their perceptions of social and cognitive engagement and teacher presence. Students in the section with the integrated instructional team also outperformed students in other sections of the same course on standardized course exams and final course grade. These results suggest that a structured instructional team composed of students can be a mechanism for promoting positive student experiences and learning in large-enrollment, remote STEM courses.

Cathode active materials and conductive additives for thermal batteries operating at high temperatures have attracted research interest, with a particular focus on compounds offering high thermal stability. Recently, FeF3 has been proposed as a candidate for high-voltage cathode materials; however, its commercialization is hindered by its low conductivity. In this study, conductive additives, such as Ni-coated carbon composites (multi-walled carbon nanotubes (MWCNTs) and carbon black (CB)), were utilized to enhance the thermal stability and conductivity of FeF3. The incorporation of metal–carbon conductive additives in the FeF3 composite increased the thermal stability by more than 10 wt.% and ensured high capacity upon conductivity enhancement. The FeF3@Ni/MWCB 15 wt.% composite containing 30 wt.% Ni exhibited a discharge capacity of ∼86% of the theoretical capacity of 712 mAh/g. The use of Ni-coated carbon-based conductive additives will allow the application of FeF3 as an effective high-temperature cathode material for thermal batteries.

In this laboratory experiment, students evaluated three silver(I) complexes as potential additives for dental adhesives based on bacterial growth inhibition, heat stability, water insolubility, and cost-effectiveness. Each student prepared and analyzed a cyanoxime ligand and its corresponding silver(I) complex. Students characterized the antibacterial activity of the silver complexes against "E." coli using a Kirby-Bauer disk-diffusion test. Laboratory data were shared among students to compare observed properties to determine which derivative is the most suitable. This multiweek experiment was used in inorganic chemistry laboratory courses to demonstrate the application of inorganic chemistry to biomedicine. The framework of the experiment was developed by a multi-institutional collaboration, and we highlight how the general procedures of the experiment were adapted to meet the needs of varying courses and contexts.

Considerable research is being conducted on the use of FeF3 as a cathode replacement for FeS2 in thermal batteries. However, FeF3 alone is inefficient as a cathode active material because of its low electrical conductivity due to its wide bandgap (5.96 eV). Herein, acetylene black and multi-walled carbon nanotubes (MWCNTs) were combined with FeF3, and the ratio was optimized. When acetylene black and MWCNTs were added separately to FeF3, the electrical conductivity increased, but the mechanical strength decreased. When acetylene black and MWCNTs were both added to FeF3, the FeF3/M1AB4 sample (with 1 wt.% MWCNTs and 4% AB) afforded a discharge capacity of approximately 74% of the theoretical capacity (712 mAh/g) of FeF3. Considering the electrical conductivity and mechanical strength, this composition was confirmed to be the most suitable.

For solid solutions with the same arrangement of atoms, the size of a unit cell depends on the size of the atoms in the unit cell. The distance between nuclei also helps determine how strongly electrons are held, which changes the band gap energy. Samples of semiconductor CH[subscript 3]NH[subscript3]Pb(I[subscript 1-"x"Br"x")[subscript 3] solid solutions were prepared; the unit cell size was measured by powder X-ray diffraction, and the band gap energy was measured by visible absorption spectroscopy. This use of a material with significant research and technological implications for solar cells illustrates the periodic properties relationship between composition, atomic size, and electron energy levels.

Providing students with timely, targeted, and useful feedback regarding their understanding of course topics is generally accepted as a good educational practice. However, when classes are very large there are challenges that prevent many instructors from accomplishing this goal. This study explores the perceived helpfulness to students and the instructor of implementing a relatively new method of automated scoring and feedback in a large section of an organic chemistry course. Prior research has shown this method to be helpful in other STEM classes. In the current study, students in two different offerings of a stand-alone organic chemistry course completed an anonymous survey in which they were asked to provide feedback about their perceptions of the new methodology. The faculty member who taught the course was also asked to respond to a series of questions regarding the feedback system. Both students and the instructor provided favorable comments about the helpfulness of the methodology and the feedback provided by it. The instructor found it helpful for providing individual feedback to students, which had previously not been possible due to the number of students enrolled in the course. Students reported that the feedback helped them to identify course topic strengths and challenge areas and that they planned to study the material differently going forward. The results indicate that this intervention can help improve student understanding of course topics and necessary actions for improving future performance in the course.

In this study, we compared the effects of cooperative flipped learning (CFL) on science achievement and learning motivation with those of simple flipped learning (SFL) and traditional lecture (TL) using a mixed-methods design. Three classes containing a total of 65 first-year high school students in South Korea were randomly assigned to the CFL, SFL, and TL conditions and taught the chemistry content of an Integrated Science curriculum in 12 lessons over about 4 weeks. In our research design, we paid particular attention to controlling the overall learning time in both the pre- and in-class contexts of the three groups. Our quantitative analysis confirmed that CFL positively affected motivation, but it negatively affected achievement. SFL showed the opposite results. In qualitative analysis, video watching in FL was rated satisfactorily in most cases, but some students reported that they lacked time. CFL inherited both the pros and cons of cooperative learning with regard to in-class interaction, and the effects of SFL depended on individual students' learning abilities. As a consequence, the balance between pre- and in-class learning should be considered carefully when implementing FL, and lab sessions are suitable candidates for this instructional system.

Formative assessment has been proven to be highly effective in improving student understanding. Nevertheless, many instructors struggle to engage in this practice, particularly when working in large-enrollment classrooms. To facilitate and foster the implementation of formative assessment in chemistry courses, undergraduate students at our institution have been trained to gather and analyze formative assessment data in real time in different classrooms. These "Learning Researchers" generate written reports that instructors use to inform their practice. In this article, we characterize what learning researchers involved in this project tended to notice in their observations and the nature of the interpretations that they built. The findings of our qualitative study provide insights into the affordances and potential constraints of using undergraduate students to collect and interpret formative assessment data to inform instructional practices in large-classroom environments.

Teaching practical chemistry skills remotely is not a task that would have been high on the agenda only a few months ago. However, in light of the COVID-19 pandemic, students around the world are having to work from home, and the chemistry education community has been forced to adapt to the new circumstances. In response, we discuss the use of simulations in place of practical laboratory work, with emphasis on the development of students' experimental design skills. The simulation of Michaelis-Menten enzyme kinetics is given as an example exercise, which other instructors could implement with immediate effect.

The transition to a remote teaching and learning environment was quick and painful at times, and yet it was a learning experience for everyone. The chemists at Centre College utilized new (to them) technology to reimagine the typical face-to-face interactions with students and colleagues. From Slack to Pear Deck to Zoom classrooms, the faculty and students engaged with a variety of platforms to continue to learn remotely despite the challenges of the global pandemic. The faculty learned the value of utilizing different types of technology, and the students learned some important skills and content.

Connecting chemical concepts with real-world applications has been demonstrated to increase persistence, student attitudes, and performance. In a one-semester general chemistry course, most laboratory exercises were designed to have direct implications on real-world issues, and students were asked to consider these implications. Students blogged about an issue related to one of the lab exercises and responded to classmates' blog postings. Surveys after the implementation of the application-based laboratory curriculum suggest students were able to more clearly connect course material with the societal impact of chemistry.

This case study aims to verify the benefits of theme-based project learning for convergent science experiments. The study explores the possibilities of enhancing creative, integrated and collaborative teaching and learning abilities in science-gifted education. A convergent project-based science experiment program of physics, chemistry and biology with the theme of environment such as seawater and wetland was designed and applied to science-gifted secondary school students in an international science contest. The program was initiated with integration of physics, chemistry and biology, interrelating both field work and laboratory work. Besides, logical discussion and humanistic writing activities with environmental issues were followed. The participants were tasked to conduct hands-on multi-disciplinary projects for both in the fields and laboratories. The projects involve raising creative and critical thinking through interpreting collected data, predicting outcomes, drawing conclusions, and presenting results. The study shows a model of project-based convergent programs for integrated experimental composition to facilitate collaborative and creative learning as well as to improve students' interests in related subjects. The study discusses ways to raise awareness of benefits from multi-disciplinary approaches through theme-based project learning in science-gifted education.

Students in the physical sciences--physics and chemistry--often take multiple-choice exams for introductory courses. Some students will write a lot on their exams, while others write very little. Does the student doing more scratch work on their exam perform better than one who does not write as much? We analyzed multiple-choice exams in physics and chemistry, measuring the amount of student writing on each exam, and explored the correlation between scratch work and exam grade. We conclude that, on average, successful students write more on their exams than unsuccessful students. Faculty should model problem-solving strategies that involve writing and drawing to increase a student's propensity for success.

BaTiO3-based oxide compounds are important ceramic materials for multilayer ceramic capacitors. In this paper, we report a sonochemical activation process of BaCO3 and TiO2 in an aqueous medium for the synthesis of BaTiO3 powders through a solid-state process. Owing to the physical and chemical effects of the ultrasonication in aqueous medium on the raw materials, BaTiO3 powders could be successfully synthesized at relatively low temperatures through a solid-state reaction, which was significantly enhanced as compared to the case in ethanol medium. Detailed investigations on the resulting BaTiO3 powders and ceramics were performed, and a model to understand the role of aqueous medium on the enhancement of the solid-state reaction was proposed in terms of Ba2+ ion leaching and zeta potential of TiO2, which are strongly affected by the pH of the aqueous medium. Our results are not only helpful for cost-effective synthesis of BaTiO3 through the highly reliable solid-state reaction process, but they also provide an understanding of the role of aqueous medium for the sonochemical process using raw materials with partial solubility in water.

The evaluation of retinal vascular structures is important for analyzing various ophthalmic diseases. Conventional trypsin digestion was used for separating retinal vasculatures in mouse, rat, and other animal models; however, the trypsin method alone is technically difficult to perform and has not been reported in zebrafish to date. In this study, we introduced a rapid and convenient method that allows the investigation of fine vessel structures at a cellular level in the relatively intact retinal vasculature of adult zebrafish. Using an anti-ZO-1 antibody, tight junction structures in retinal vessels were examined in detail and several different cell types constituting blood vessels in arterial and capillary areas were identified. In addition, using cell type-specific antibodies, we identified smooth muscle cells, blood cells, and endothelial cells in the retinal vasculature. Finally, using the hyperglycemic model, we observed the dilation of retinal vessels, the downregulation of tight junction proteins, and the reduction in smooth muscle cells. Based on these results, we provide a rapid and convenient method for the study of retinal vasculature disease in the zebrafish animal model.

In this paper, we present the details of the development of a smartphone spectrometer for education using a 3D printer and characterized the performance by comparison with a paper craft spectrometer. The optical design and the narrow slit used in the build resulted in the formation of accurate images of the slit on the image sensor leading to a superior resolution compared to the paper craft spectrometer. The measured spectral resolution of the 3D-printed smartphone spectrometer was 0.4 nm, which was narrower than those of other smartphone spectrometers. Increasing the exposure time of the phone's camera revealed the fine structure of a spectrum with high resolution. The baffle structure inside the spectrometer proved to be effective in removing noise when the exposure time was increased. We expect the 3D-printed smartphone spectrometer proposed in this paper can be useful as an education tool for students to understand the various aspects of light, atoms, chemistry, and physics.

Abstract Abscisic acid (ABA) is a phytohormone that plays an important role in the adaptive responses to abiotic stresses. We examined the metabolic changes in transgenic soybean that over-expressed Arabidopsis ABA responsive element-binding factor 3 (ABF3), which participates in drought tolerance. Transgenic and non-transgenic plants were exposed to a water deficit, and their metabolic differences were verified by untargeted GC‒MS and LC‒MS/MS analyses. A total of 64 and 476 primary and secondary metabolites from leaf extracts were identified based on GC‒MS and LC‒MS/MS platforms, respectively. Principal component analysis derived from both GC‒MS and LC‒MS/MS data showed a clearly greater separation in the metabolite profiles among three different degrees of drought stress. However, no discrimination of metabolites between transgenic and non-transgenic plants was apparent. Furthermore, except for some free amino acids, quantitative differences in relative levels of those metabolites were less than 50% between genotypes. These results suggest that, during periods of drought, overexpression of ABF3 in transgenic soybean might result in a negligible variance in primary and secondary metabolism when compared with its non-transgenic counterpart.

Thermal vapor condensation of melamine at various temperatures was used to fabricate thin graphitic carbon nitride (g-C3N4) films on fluorine-doped tin oxide (FTO) coated glass substrates. Photoanodic (n-type) and photocathodic (p-type) responses were observed simultaneously in the g-C3N4 films. The g-C3N4 film formed at 520 °C with the longest average lifetime of the photo-excited electrons shows the best cathodic photocurrent performance, which was then chosen for electrochemical and photoelectrochemical reduction of CO2. When the basic electrolyte (CO2-saturated 0.5 M KHCO3, pH = 7.6) was adopted, CO2 was electrochemically converted into formaldehyde ((54.6 μM/h)) in the liquid product. When the acidic electrolyte (CO2-saturated 0.5 M KCl, pH = 4.1) was adopted, formaldehyde (39.5 μM/h) and ethanol (15.7 μM/h) were generated through photoelectrochemical reduction, stimulated by the presence of sufficient protons from the electrolyte in the reduction process. Therefore, the pure g-C3N4 film has a great potential for CO2 reduction to value-added liquid hydrocarbons products via electrochemical or photoelectrochemical ways.

There has been an immense effort by global pharmaceutical companies to develop anti-COVID-19 drugs, including small molecule-based RNA replication inhibitors via drug repositioning and antibody-based spike protein blockers related to cell entry by SARS-CoV-2. However, several limitations to their clinical use have emerged in addition to a lack of progress in the development of small molecule-based cell entry inhibitors from natural products. In this study, we tested the effectiveness of kuwanon C (KC), which has mainly been researched using in silico docking simulation and can serve as an effective building block for developing anti-COVID-19 drugs, in blocking the spike S1 RBD:ACE2 receptor interaction. KC is a natural product derived from Morus alba L., commonly known as mulberry, which has known antiviral efficacy. Molecular interaction studies using competitive ELISA and the BLItz system revealed that KC targets both the spike S1 RBD and the ACE2 receptor, successfully disrupting their interaction, as supported by the in silico docking simulation. Furthermore, we established a mechanism of action by observing how KC prevents the infection of SARS-CoV-2 spike pseudotyped virus in ACE2/TPRSS2-overexpressing HEK293T cells. Finally, we demonstrated that KC inhibits clinical isolates of SARS-CoV-2 in Vero cells. Future combinations of small molecule-based cell entry inhibitors, such as KC, with the currently prescribed RNA replication inhibitors are anticipated to significantly enhance the efficacy of COVID-19 therapies.

Polyethylene degradation has a significant ecological impact but is also economically beneficial because it generates fuels and useful chemical products. Our study mainly describes the cleavage of C-C and C-H bonds when polyethylene (dispersed in 1-octadecene) was low-temperature heat-treated in two steps, at 180 and 250 °C, for 24 h for each step. Finally, it was converted to a mixture of the precursors of gasoline and diesel oil with a trace amount of wax. A series of reactions resulted in cracking, dehydrogenation and oxidation, hence producing polycarboxylic acids and saturated and unsaturated hydrocarbons. ESI-MS analysis revealed that mixed oil consisted of low carbon number hydrocarbons and their derivatives of carboxylic acids, with the carbon number ranging from C-6 to C-18. In the trace amount of wax, complicated carboxylic acids and hydrocarbons with carbon number C-22 to C-58 were also identified. FT-IR analysis further confirmed the presence of carboxylic acid derivatives and double bonds in the degradation products. γ-Al2O3 nanorods effectively catalyzed the degradation process by enhancing the C-C chain length in the products. Lewis acid (Al) and Lewis base (oxygen) in the γ-Al2O3 induced ionic character of the C-C bond chain, which led to the efficient cracking of the C-C bond. Poor shielding effect, smaller atomic size and greater ionization energy made Ga a stronger Lewis acid compared to Al; hence, Ga-doped γ-Al2O3 catalyzed the degradation process even more effectively.

This paper describes a first-year undergraduate exercise involving the synthesis of an "unknown" polyiodide salt, (NMe[subscript 4])[I[subscript 5]], and the determination of its formula using the classic iodine-thiosulfate (iodometric) titration. The exercise introduces students to simple synthetic and titrimetric techniques, assists the development of their chemical and glassware handling and titrimetric skills, and acquaints them with unfamiliar polyiodide compounds. It also introduces students to key chemical concepts such as The Law of Definite Proportions, percentage elemental composition, empirical chemical formulas, quantitative stoichiometric reactions, and halogen catenation.

This paper describes an upper-division undergraduate exercise involving the synthesis and iodometric and infrared spectroscopic analysis of the peroxide double salt [Zn(NH[subscript 3])[subscript 4]][Mo(O[subscript 2])[subscript 4]]. Here, iodometric methods are employed to determine the peroxide content of the compound, a procedure widely used for the industrial analysis of peroxides. The exercise increases student proficiency in synthesis, the handling of reactive chemicals, and titrimetry, while introducing aspects of metal peroxide chemistry and key chemical concepts related to high-coordination number complexes, kinetic versus thermodynamic stability, and group theoretical treatments of vibration spectroscopy.

In accordance with the requirements for the National Curriculum Statement for both Life sciences and Physical sciences and the importance of community engagement in Higher Education in South Africa, this paper described the use of the lecture-demonstration "A Pollutant's Tale" to create climate change awareness amongst school learners. "A Pollutant's Tale" was performed to a total of 981 school learners and 25 educators from both advantaged and disadvantaged areas of the Western Cape province of South Africa. Both learners and educators were asked to complete their respective questionnaires after the demonstration. The learners' attitudes towards science and the learning of science concepts after the demonstration were described. The educators' views, perceptions and evaluations on using such demonstrations to promote positive attitudes towards science were also discussed. Both the learners and their educators thoroughly enjoyed the demonstration of "A Pollutant's Tale" and they were also made aware of the causes and effects of climate change on our environment. More importantly, this outreach initiative has helped to spark an interest in the learners' minds not only about chemistry but about science in general.

Plant-derived substances exhibit antioxidant and antibacterial activities and have been proven to have beneficial effects in wound healing and skin regeneration. Plant stem cells have recently received much attention as research materials in cosmetic development because they promote regeneration after damage. In this paper, we demonstrate for the first time that the plasma treatment of stem cells obtained from rice-seed embryos can be effective in enhancing antioxidant activity and in regenerating human skin. We investigated this potential utilizing micro-DBD (Dielectric Barrier Discharge) plasma as a pretreatment technique to enhance the vitality and functional activity of rice stem cells. The results of the cell culture experiments show that plasma-treated rice stem cell extracts (RSCE) have promising antioxidant and anti-skin aging activities. The results of quantitative real-time PCR (qRT-PCR) for major antioxidant enzymes and anti-aging genes confirm that the plasma technique used in the pretreatment of RSCE was able to enhance cell activities in skin regeneration, including cell survival, proliferation, and collagen enhancement for Human Fibroblast (HFB) degraded by oxidative stress. These results show that the relatively low energy of less than 300 W and an amount of NOx-based reactive nitrogen species (RNS) from plasma discharge of about 3 μL/L were the key factors and that RSCE, of which the antioxidant activity was enhanced by plasma treatment, appeared to be a major contributor to the protective effect of HFB against oxidative stress. Plasma-treated RSCE induced excellent anti-aging properties by stimulating HFB to promote collagen synthesis, thereby promoting skin regeneration. These properties can protect the skin from various oxidative stresses. This study demonstrates that plasma-treated extracts of stem cells derived from rice-seed embryos have an excellent regenerative effect on aging-treated HFB. Our results demonstrate the potential utility of plasma-treated RSCE as a skin anti-aging agent in cosmeceutical formulations for the first time.

Uniform-size rutile TiO2 microrods were synthesized by simple molten-salt method with sodium chloride as reacting medium and different kinds of sodium phosphate salts as growth control additives to control the one-dimensional (1-D) crystal growth of particles. The effect of rutile and anatase ratios as a precursor was monitored for rod growth formation. Apart from uniform rod growth study, optical properties of rutile microrods were observed by UV−visible and photoluminescence (PL) spectroscopy. TiO2 materials with anatase and rutile phase show PL emission due to self-trapped exciton. It has been observed that synthesized rutile TiO2 rods show various PL emission peaks in the range of 400 to 900 nm for 355 nm excitation wavelengths. All PL emission appeared due to the oxygen vacancy present inside rutile TiO2 rods. The observed PL near the IR range (785 and 825 nm) was due to the formation of a self-trapped hole near to the surface of (110) which is the preferred orientation plane of synthesized rutile TiO2 microrods.

This paper describes a laboratory exercise used to address the ongoing need for nanotechnology-related, hands-on laboratory experiences for undergraduate students. Determination of the electrochemical behavior of student-fabricated silver nanogrids is reported. Students successfully used cyclic voltammetry to analyze silver nanogrids printed using microcontact printing and subsequent metallization. The silver nanogrids exhibit electrochemical behavior similar to that of electrodes manufactured in industry. Additionally, optical microscopy, atomic force microscopy, and scanning electron microscopy were used to assess nanogrid quality and dimensions.

An anode bimetallic catalyst comprising Ni-Pd alloy nanoparticles was loaded on acid-treated multi-walled carbon nanotubes (MWCNTs) for application in a direct urea fuel cell. The bimetallic catalyst and MWCNTs were synthesized by a hydrothermal method at 160°C for 5 h. To reduce the catalyst particle size, alkaline resistance, and facilitate their uniform distribution on the surface of the MWCNTs, phosphorus (P) was added to the Ni-Pd/MWCNT catalyst. The effects of P on the distribution and reduction in size of catalyst particles were investigated by Brunauer–Emmett–Teller analysis, transmission electron microscopy, and X-ray diffraction analysis. The enhanced catalytic activity and durability of the P-containing catalyst was confirmed by the high current density [1897.76 mA/cm2 (vs. Ag/AgCl)] obtained at 0.45 V in a 3 M KOH/1.0 M urea alkaline aqueous solution compared with that of the catalyst without P [604.87 mA/cm2 (vs. Ag/AgCl)], as determined by cyclic voltammetry and chronoamperometry. A Urea–O2 fuel cell assembled with a membrane electrode assembly comprising the Ni-Pd(P)/MWCNT catalyst delivered peak power densities of 0.756 and 3.825 mW/cm2 at 25 and 60°C, respectively, in a 3 M KOH/1 M urea solution.

In this study, we fabricated a cathode with lower amounts of additive materials and higher amounts of active materials than those of a conventional cathode. A thermal battery was fabricated using FeS2 treated foam as the cathode frame, and its feasibility was verified. X-ray diffraction, transmission electron microscopy, and scanning electron microscopy were used to analyze the effects of thermal sulfidation temperature (400 and 500°C) on the structure and surface morphology of the FeS2 foam. The optimal temperature for the fabrication of the FeSx treated foam was determined to be 500°C. The FeS2 treated foam reduced the interfacial resistance and improved the mechanical strength of the cathode. The discharge capacity of the thermal battery using the FeS2 treated foam was about 1.3 times higher than that of a thermal battery using pure Fe metal foam.

Dye-containing pollutants are currently a threat to the environment, and it is highly challenging to eliminate these dyes photocatalytically under visible light. Herein, we designed and prepared a ZnO/CuO/g-C3N4 (ZCG) heterostructure nanocomposite by a co-crystallization procedure and applied it to eliminate pollutants from wastewater via a photocatalytic scheme. The structural and morphological features of the composite confirmed the formation of a ZCG nanocomposite. The photocatalytic capability of the ZCG photocatalyst was investigated via the decomposition of methylene blue dye. The outstanding activity level of 97.46% was reached within 50 min. In addition, the proficiency of the ZCG composite was 753%, 392%, 156%, and 130% higher than photolysis, g-C3N4, CuO, and ZnO, respectively. Furthermore, the photodeterioration activity on Congo red was also evaluated and found to be excellent. The enhanced catalytic achievement is attributed to the construction of heterojunctions among the constituent compounds. These properties boost the charge transfer and decrease the recombination rate. Moreover, the reusability of the ZCG product was explored and a negligible photoactivity decline was detected after six successful runs. The outcomes suggest the as-prepared nanocomposite can be applied to remove pollutants, which opens a new door to practical implementation.

The coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite the development of vaccines, the emergence of SARS-CoV-2 variants and the absence of effective therapeutics demand the continual investigation of COVID-19. Natural products containing active ingredients may be good therapeutic candidates. Here, we investigated the effectiveness of geraniin, the main ingredient in medical plants Elaeocarpus sylvestris var. ellipticus and Nephelium lappaceum, for treating COVID-19. The SARS-CoV-2 spike protein binds to the human angiotensin-converting enzyme 2 (hACE2) receptor to initiate virus entry into cells; viral entry may be an important target of COVID-19 therapeutics. Geraniin was found to effectively block the binding between the SARS-CoV-2 spike protein and hACE2 receptor in competitive enzyme-linked immunosorbent assay, suggesting that geraniin might inhibit the entry of SARS-CoV-2 into human epithelial cells. Geraniin also demonstrated a high affinity to both proteins despite a relatively lower equilibrium dissociation constant (KD) for the spike protein (0.63 μM) than hACE2 receptor (1.12 μM), according to biolayer interferometry-based analysis. In silico analysis indicated geraniin’s interaction with the residues functionally important in the binding between the two proteins. Thus, geraniin is a promising therapeutic agent for COVID-19 by blocking SARS-CoV-2’s entry into human cells.

Electrochemical analysis is an important skill to teach in chemistry curricula because it is a critical tool in current high-impact chemical research. Electrochemistry enables researchers to analyze a variety of systems extending from molecules to materials that encompass research themes ranging from clean energy to substrate activation in biological systems. Specifically, it can reveal information about catalytic efficiency, the role of catalysts, and the nature of chemical reduction and oxidation (redox) processes. Researchers working in the area of catalysis rely heavily on electrochemistry, using it to identify effective catalysts and optimize reaction conditions. This laboratory experiment begins with an introductory tutorial to electrochemistry by guiding students through the use of several electrochemical techniques using the ferricyanide/ferrocyanide redox couple as a model system. The techniques covered in the tutorial include cyclic voltammetry, differential pulse voltammetry, Tafel analysis, and bulk electrolysis. The protocol then applies these techniques to electrocatalysis by identifying and characterizing catalysts for hydrogen and oxygen generation in the water electrolysis reaction. Electrochemical methods are connected to current chemical research by focusing on catalysis in the context of renewable energy, which is a current societal and curricular imperative. The entire laboratory protocol described herein is conducted in groups of two to three students in a four hour laboratory period and is suitable for upper-level physical, analytical, or inorganic chemistry.

Refrigerant charge faults, which occur frequently, increase the energy loss and may fatally damage the system. Refrigerant leakage is difficult to detect and diagnose until the fault has reached a severe degree. Various techniques have been developed to predict the refrigerant charge amount based on steady-state operation; however, steady-state experiments used to develop prediction models for the refrigerant charge amount are expensive and time-consuming. In this study, a prediction model was established with dynamic experimental data to overcome these deficiencies. The dynamic models for the condensation temperature, degree of subcooling, compressor discharge temperature, and power consumption were developed with a regression support vector machine (r-SVM) model and start-up experimental data. The dynamic models for the condensation temperature and degree of subcooling can predict the distinct start-up characteristics depending on the refrigerant charge amount. Moreover, the estimated root mean square error (RMSE) of the condensation temperature and degree of subcooling of the test data are 0.53 and 0.84 °C, respectively. The refrigerant charge is one of the predictors that defines the dynamic characteristics. The refrigerant charge can be estimated by minimizing the RMSE of the predicted values of the dynamic models and experimental data. When the dynamic characteristics of the two predictor variables, “condensation temperature” and “degree of subcooling” are used together, the average prediction error of the test data is 2.54%. The proposed method, which uses the dynamic model during start-up operation, is an effective technique for predicting the refrigerant charge amount.

Kaempferol (KO) and kaempferol 7-O-rhamnoside (KR) are natural products from various oriental herbs such as Geranii Herba. Previous studies have reported some biological activities of KO and KR; however, their effects on PD-1/PD-L1 interaction have not been reported yet. To elucidate their inhibitory activities on PD-1/PD-L1 protein–protein interaction (PPI), biochemical assays including competitive ELISA and biolayer interferometry (BLI) systems were performed. Cellular PD-1/PD-L1 blocking activity was measured in a co-culture system with PD-1 Jurkat and PD-L1/aAPC CHO-K1 cells by T-cell receptor (TCR) activation-induced nuclear factor of activated T cells (NFAT)-luciferase reporter assay. The detailed binding mode of action was simulated by an in silico docking study and pharmacophore analysis. Competitive ELISA revealed that KO and its glycoside KR significantly inhibited PD-1/PD-L1 interaction. Cellular PD-1/PD-L1 blocking activity was monitored by KO and KR at non-cytotoxic concentration. Surface plasmon resonance (SPR) and biolayer interferometry (BLI) analysis suggested the binding affinity and direct inhibition of KR against PD-1/PD-L1. An in silico docking simulation determined the detailed mode of binding of KR to PD-1/PD-L1. Collectively, these results suggest that KR could be developed as a potent small molecule inhibitor for PD-1/PD-L1 blockade.

For the CO2 capture process via the cyclic adsorption/desorption method, one emerging catalyst is the use of amine-functionalized silica. This study focused on comparing the CO2 capture performance of diamines with ethyl and propyl spacers and the degradation species formed after long-term exposure to various acidic gases such as SO2 and NO2 at elevated temperatures. Adsorbents were prepared via the incipient wetness technique and then subjected to thermogravimetric measurements and in situ FT-IR analyses. 2NS-P/Kona95, which contains a propyl spacer, showed fewer degradation species formed based on its IR spectra and better stability with its long-term exposure to various acidic gases. Thus, the incorporation of amines with a large number of nitrogen groups of propyl or longer spacer length could be a promising CO2 capture material.