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Purpose: This paper presents two educational gamified virtual labs and investigates different methods of including gamified elements in virtual labs used for teaching. The purpose of this study is to investigate if immersive gamified virtual labs can be used as effective pedagogical tools by properly incorporating them into higher education curricula to assist low-risk active learning and student engagement. Design/methodology/approach: This research design comprises two gamified virtual labs including nine essential experiments of biology and chemistry integrated into the higher education curriculum of the Foundation of Science at an international University. Students filled in a survey after participating in the lab to shed light on appropriate ways of using gamification approaches in virtual labs. Findings: From the predominant findings of the study, gamified virtual labs increase student involvement thereby enhancing knowledge development with active learning and may be a potentially suitable pedagogical tool for low-risk interactive learning. Research limitations/implications: Limitations of the study include findings based on gamified virtual labs but not comparing the gamified virtual labs to simple virtual simulations to further investigate the pedagogical approach and understand the student perceptions in a simple virtual simulation and a gamified virtual lab. Practical implications: The findings of this study will provide evidence that gamified virtual labs integrated into higher education curricula as supplementary tools for laboratory experimentation improve the educational delivery process. Originality/value: This research highlights an appropriate way of integrating 3D virtual labs into practical curricula while discussing the benefits.

Non-science majors often lack motivation to take science courses required for their graduation, because these courses are usually taught in a lecture format and are disconnected from their everyday life and needs related to future careers. This two-phase action research, utilizing argumentative writing (AW) supported with online simulation, was conducted over three academic years in a college chemistry course designed for non-science majors. Phase 1, a quasi-experimental design (n = 134), examined the treatment effects of AW projects and determined the components of AW that contributed to student gains in conceptual performance. The results showed that students in the AW group scored significantly higher in conceptual performance than the control group. Five AW components predicted student gains in conceptual performance: accuracy of claim, relationship between claim and question, relationship between claim and evidence, use of multiple examples, and use of appropriate writing style. Phase 2, a single group design (n = 118), explored the inter-relationships between pre-/post-course knowledge, pre-/post-course motivation, and students' performance on AW projects. The results showed that students' motivation to learn chemistry at the beginning of the course is a significant predictor of their conceptual performance. Pathway analysis found that the performance of AW projects in low motivation students was affected by extrinsic motivation (grades, career). Their performance in AW projects did not affect their post-course knowledge. In contrast, the performance in AW projects by high motivation students was affected by intrinsic motivation and self-determination. They cumulatively built knowledge through AW projects that eventually affected post-course knowledge.

Students' perceived values and costs of learning chemistry influence their performance and intentions of choosing chemistry-related majors or careers. Based on Situated Expectancy-Value Theory, this study adopted a mixed method approach to examine the conceptualization of values and costs among Chinese high school students and identify their relations with chemistry test performance across gender. Qualitative content analyses revealed that students' perceived values for chemistry could be categorized into five broad categories: utility value, epistemic value, intrinsic value, aesthetic value, and social value. Chi-square tests and multidimensional scaling revealed that boys and girls perceived values and costs in different ways: relational utility value was more salient to boys while practical utility value and epistemic value were more salient to girls; Girls perceived greater distinctions among different types of values (i.e., epistemic- and emotional-related values) and costs (i.e., emotional and ego cost) than boys. Independent t tests showed that boys reported mostly higher values and lower costs than girls. Hierarchical multiple regression found that gender, intrinsic value, social value and cost significantly predicted students' chemistry exam scores. In addition, the interaction between gender and social value was identified. This study highlights the complexity of perceived values and costs of learning chemistry and provide implications for developing activities or interventions that foster student engagement in chemistry learning.

Errors are natural elements of the learning process and provide a high potential to promote students' learning outcomes. In recent years, there has been much research about learning from errors. However, we know little about the relationship between students' error beliefs in chemistry and chemistry learning outcomes at present. Thus, the aim of this study was to explore the mechanisms of chemistry behavioral and cognitive engagements, adaptive reactions towards errors in chemistry and error beliefs in chemistry, and offer suggestions to the improvement of students' chemistry learning outcomes. We assessed all variables in eight different schools in China (N = 1352 students, Grade 10) and used structural equation modelling (SEM) to check the direct and indirect relationships between four variables. Our findings revealed that (1) chemistry behavioral and cognitive engagements, adaptive reactions towards errors in chemistry and error beliefs in chemistry significantly positively predicted students' chemistry learning outcomes; (2) both (a) adaptive reactions towards errors in chemistry and (b) chemistry behavioral and cognitive engagements acted as significant mediators between error beliefs in chemistry and chemistry learning outcomes; (3) the chain mediating effect of error beliefs in chemistry [right arrow] adaptive reactions towards errors in chemistry [right arrow] chemistry behavioral and cognitive engagements [right arrow] chemistry learning outcomes was significant. Finally, we discussed the important findings, pointed out the educational implications, acknowledged our study's limitations and suggested directions for future study.

The Yuan T. Lee Foundation Science Education for All (YTLF) has implemented a science camp for students with visual impairments in central Taiwan since 2009. The implementation of the camp serves as an informal science education practice model that informs curriculum design and development, personnel preparation and organization, as well as perceptions toward students with visual impairments. This article gives an overall introduction to the implementation of the camp in addition to the ideas and the outcomes.

Based on quantitative survey data collected from an inquiry-based general chemistry laboratory course, the current study used marginal models to evaluate changes in students' teamwork and problem-solving skills, attitudes to teamwork, and willingness to explore new issues before and after the course. The results suggest that introductory-level inquiry-based laboratory courses may not influence all students in the same way. By the end of the course, novice learners with a lower team-based problem-solving starting point reported greater learning growth than more experienced learners. As a result, the gap between novice learners' teamwork and problem-solving skills and attitudes and those of more experienced learners narrowed. However, the results also suggest that, by the end of the course, more experienced learners had developed negative attitudes to teamwork and problem-solving. In addition, deeper learning was found to be associated with improvements in team-based problem-solving for both novice and more experienced learners. Deep learning levels were related to both the magnitude and direction of attitude change, particularly for more experienced learners. These findings suggest that offering introductory-level inquiry-based laboratory courses is beneficial to narrow achievement gaps. In order to empower students of all experience levels, a differentiated instruction method should be adopted to accommodate students' varied needs.

Cola beverages are widely consumed and popular among students; they can be used as safe reagents to replace toxic chemical dyes. In this study, a safe and improved experiment is described, which successfully demonstrates Beer's law and adsorption process using activated carbon as the adsorbent and cola as the adsorbate. The results of this study demonstrate that the use of cola has achieved good evaluation for the teaching of the Beer's law and the adsorption phenomenon. The potential learning outcomes of the experiment include the principles of spectrophotometry, operation of spectrophotometer, Beer's law and its limitations, derivation of linear regression equation, and construction of adsorption isotherms. This experiment can be used as a safe spectrophotometric protocol to determine the adsorption isotherms for undergraduate learning of analytical or general chemistry.

Prior research has demonstrated the important role of chemistry students' affect in academic performance. Likert-scale surveys are the most prevalent tools to measure students' affect within chemistry education research, however, data collected through a Likert-scale survey may exhibit response style bias which can hinder accurately measuring students' affect. This study investigates the utility of a novel survey methodology, termed rank-sort survey, in understanding students' academic motivation in a general chemistry course. Informed by Q methodology, in a rank-sort survey participants rank a set of statements in terms of level of agreement with limits in place on how many items can be assigned a particular rank. In this investigation, a rank-sort survey was developed by using statements from an existing Likert-scale instrument, the Academic Motivation Survey in Chemistry. Data collected from the rank-sort surveys, compared to Likert-scale surveys, showed a better alignment with self-determination theory, the underlying theoretical framework, and a better ability to predict students' academic performance in chemistry. The study also discusses which surveys in chemistry education research are likely to benefit from adopting a rank-sort approach.

The Chemistry Self-Concept Inventory (CSCI) is a widely used instrument within chemistry education research. Yet, agreement on its overall reliability and validity is lacking, and psychometric analyses of the instrument remain outstanding. This study examined the psychometric properties of the subscale and item function of the CSCI on 1140 high school chemistry students in the midwestern United States. Using exploratory factor analysis, we found that a five-factor model, distinct from previous studies' models, fit our data best. Using this model in Rasch analysis, we found several items within the Mathematics subscale that showed unusual item difficulty, significant misfit, and low item discrimination. Implications for future use of the CSCI are discussed.

In this laboratory experiment, the synthesis and characterization of H[subscript 5]PV[subscript 2]Mo[subscript 10]O[subscript 40]@Cu[subscript 3](BTC)[subscript 2] (denoted as NENU[subscript -9], H[subscript 3]BTC = 1,3,5-benzenetricarboxylic acid) and its application in fuel desulfurization were performed. This experiment is designed for advanced undergraduate students majoring in chemistry. In this experiment, students experience the universal procedures of solution syntheses, get knowledge of several modern instrumental techniques (PXRD, FTIR, SEM, and GC) widely utilized in chemical research, and learn the general procedure of heterogeneous catalytic reaction. Upon the completion of the experiment, not only was students' teamwork spirit cultivated by data-sharing and discussion in their assigned group, but also their environmental protection awareness was stimulated by performing a catalytic oxidative desulfurization reaction, a potential technology that may reach the goal of reducing sulfur oxide emissions. Moreover, students' basic chemistry knowledge (inorganic, coordination, organic, and analytical chemistry) was consolidated by using it to analyze experimental phenomena and results.

In light of the COVID-19 pandemic, the transition from traditional face-to-face lectures to online learning, as well as the adoption of technology-enabled active learning in the classroom, has been accelerated. Here, we introduce the use of Telegram as a technological tool to support remote learning by helping students identify gaps in their content knowledge with ease and convenience. This was done by designing a quiz based on relevant topics on the Telegram Quiz Bot, while adding an element of gamification, whereby students compete in group chats for correctness and speed. Overall, the majority of the students responded positively to the use of the Telegram Quiz Bot.

Online multiple-choice instruments to diagnose students' understanding of science concepts are easily developed and administered to students using Google Forms. This article describes a web-based three-tier multiple-choice test for the formative assessment of students' understanding of chemical bonding. The results obtained can lead to follow-up discussions with students if they have difficulties with the concepts involved.

Some students struggle with chemistry because they do not find the relevance between chemistry content and their lives or they perceive their intelligence as fixed. Social-psychological interventions (SPIs), brief interventions that target students' subjective experiences, were developed to address these issues. As a result, SPIs have been associated with gains in students' academic performance, attitude, and persistence in various instructional settings; however, only a limited number of studies have explored SPIs within a chemistry context. This study evaluated the effectiveness of two SPIs, a growth mindset intervention (GMI) and a utility value intervention (UVI), on promoting students' academic performance and attitude in a general chemistry course with a large class size. This study also explored a theoretical explanation for the relationship among SPIs, attitude, and academic performance. Each SPI was designed to facilitate instructional adoption and was implemented by posting three prompts incorporated into homework assignments. The results show that the UVI led to a consistent improvement in student achievement, and among students who begin the course with lower attitudes toward chemistry, the UVI led to an improvement in students' emotional satisfaction and utility value. The UVI's improvement in academic performance was also observed with a group of students who have been underrepresented in the sciences, although a smaller sample size prevented finding statistical significance. The GMI improved academic performance relative to a comparison group but not to the extent observed with the UVI. The cost-to-benefit ratio associated with adopting SPIs within chemistry instruction seems highly favorable and thus warrants strong consideration among chemistry instructors.

The visualization of chemical compounds in three-dimensions is a foundational skill in the study and practice of chemistry and related fields, and one which has the potential to be supported by interaction with virtual models. Here, we present a collaborative learning activity piloted in first-year chemistry which investigates if inquiry-driven interactive technology can contribute meaningfully to student conversations around this topic, and how students' conversations and practices may shift when driven by feedback from an interactive simulation. Our initial observations from this pilot project suggest that students engaged in collaborative sense-making and discussion around key ideas throughout this activity. Students' post-activity reflections also highlighted their positive experiences and increased confidence with the topic afterwards. The unique dynamics of these interactions lead us to propose a novel framing of interactive visualizations as participants rather than merely as resources in student learning conversations.

Success in undergraduate biology courses relies upon a firm grounding in chemical principles. We sought to raise students' awareness of the connection between these two disciplines and to improve their understanding of each by carrying out a pilot project that integrated the curricula of Principles of Chemistry II (CHEM1212K) and Principles of Biology I (BIOL1107K) during the Fall 2016 semester. The study involved two course pairs: one section of each course delivered in the traditional non-integrated manner and a second pair of sections that were integrated across the chemistry and biology disciplines in both the scope and sequence of the content delivery. Both integrated and non-integrated sections were taught by the same instructors, who have expertise in both chemistry and biology to ensure a full understanding of both courses' content. Attitudinal surveys administered at the beginning and end of the semester showed that students in the integrated BIOL/CHEM section of our pilot study appreciated the delivery of an integrated curriculum and improved their awareness of the connections between the two disciplines. End-of-course assessments of topic mastery demonstrated improvements in the integrated students' capacity to understand and apply both biology and chemistry topics compared to students in the non-integrated sections.

This article introduces a novel experiment that involves vitrimers, a new type of polymer, in polymer chemistry and physics lab courses for undergraduate students. Vitrimers are permanently cross-linked networks that can be reprocessed under certain external stimuli. Therefore, they combine the advantages of traditional thermoplastics (excellent reprocess ability) with thermosets (outstanding mechanical properties and environmental stability). They can be regarded as a kind of "special thermoset", which moves this industry toward a more sustainable path, as they are conducive to decreasing thermosetting wastes, reducing environmental pollution, and cutting down the waste of resources. From this lab class, students obtained more experience in the preparation and characterization of polymers. They also learned the concepts of dynamic chemistries and vitrimers and gained a better understanding of the advantages and limitations of thermosets and thermoplastics, as well as a strategy for making a reprocess able thermoset polymeric material. It also fostered students' interest in functional materials and inspired them to design other functional materials. Moreover, this experimental setup is convenient and safe for implementation and dissemination in most undergraduate laboratory classes.

The prompt introduction of single-molecule science into undergraduates' curricula is an urgent but challenging task. However, the research experiments are often too complicated and the instruments are too expensive to be widely transferred into a compulsory course of undergraduate students. Herein, we introduce a recently developed nanopore technique into an accessible laboratory course for students with the advantages of simple operation, high repeatability, and low cost. The nanopore course serves to help undergraduates in practice to understand single-molecule behaviors, think at a single molecule level, and gradually develop single-molecule solutions for scientific issues. The learning activities for undergraduate students include setup of the instrument, fabrication of a biological nanopore on an artificial lipid bilayer membrane, detection of individual oligonucleotides, and data analysis. An experiment example is single-molecule detection of the model DNA sample poly(dA)[subscript n] (n = 4, 5) using the aerolysin nanopore. As our developed nanopore sensing system is simple, portable, and easy to handle, the experiment course could be implemented and popularized in undergraduates' laboratory education. For the undergraduate students who have taken general chemistry and/or biochemistry courses, this hands-on experience of nanopore experiments would benefit them with a better understanding of the chemical world at a single-molecule level and further using single-molecule tools in various applications including DNA and/or protein sequencing.

The current study examined the psychometric properties of scores from the Redox Concept Inventory (ROXCI) scores using both confirmatory factor analysis (CFA) and Rasch analysis. CFA analysis provides evidence for construct validity, and Rasch analysis demonstrates the performance of ROXCI items in terms of their accuracy in estimating person ability as well as providing person ability estimates for the distractor analysis. Our work provides some insights into ROXCI items that were not presented in the original development paper. Results showed that ROXCI is an appropriate instrument to measure student understanding of redox reactions at the introductory college level based on the sample data, because ROXCI items were especially useful for discriminating between students with latent abilities below +0.5 logits but not as much for students with higher latent abilities. Based on the trace plots, distractor analysis found improved scores for 12 out of 18 items after the instruction on the redox reaction with small to medium effect size, little change in scores for 2 items, and no improved scores for 4 items, which were the items with nonsignificant factor loadings in the CFA analysis. In addition, item feature analysis was performed for the first time for items in chemistry concept inventories to evaluate the effects of item features on item performance, which provided some useful information for test developers in the future. Results showed that the item type had significant effects on the item performance after controlling for the person feature effect.

Conceptually understanding chemistry requires the ability to transition among representational levels to use an understanding of submicroscopic entities and properties to explain macroscopic phenomena. Past literature describes student struggles with these transitions but provides limited information about upper-level post-secondary chemistry students' abilities to transition among levels. This group is of particular interest as they are engaging in potentially their final training before entering a career as professional chemists, thus if students are likely to develop this skill during their formal education it should be manifest among this group. This study characterized analytical chemistry students' responses to open-ended assessments on acid--base titrations and thin-layer chromatography for the use of sub-microscopic entities or properties to explain these macroscopic phenomena. Further, to understand whether explanatory statements were an expectation inherent in the instructional context of the setting, the analytical chemistry instructor's lectures on acid--base titrations and thin-layer chromatography were analyzed with the same framework. The analysis found that students seldom invoked explanatory statements within their responses and that congruence between lectures and responses to assessment was primarily limited to the use of macroscopic, descriptive terms. Despite the fact that the lecture in class regularly invoked explanatory statements in one context, this did not translate to student use of explanatory statements. To further test the hypothesis that analytical chemistry students struggle with explanatory statements, a follow-on study was also conducted among a second cohort of students reviewing their responses when specifically prompted to use sub-microscopic entities to explain a macroscopic phenomenon. The results suggest that fewer than half of the students showed proficiency on generating explanatory statements when explicitly prompted to do so. Instructional implications to promote explanatory statements are proposed in the discussion.

Georgia Gwinnett College (GGC) is an open-access, four-year, public liberal arts college that emphasizes excellent instruction through active learning and small class sizes. The COVID-19 pandemic presented unique challenges to GGC general chemistry instructors as they sought to actively engage students in a new online setting. We reflect on the challenges faced by our college during this pandemic by analyzing student surveys, instructor reflections, and grade distributions across 20 sections of general chemistry 1 and 2 taught by 15 different instructors. We consider the most important challenges faced by students and the technology rapidly adopted by instructors. We then present three main themes found in the instructor reflections and consider the implications for going forward.

Argumentative writing advances students' understanding of scientific concepts, ability to communicate, and scientific literacy. However, it remains unclear which components of argumentative writing drive such advancement. Further, most studies on argumentative writing have focused on students majoring in science, rather than in the nonsciences. The purpose of this study was to determine which components of argumentative writing are predictors of academic achievement in a general chemistry course designed for nonscience majors. The participants included 163 undergraduates at a public university. The quality of argumentative writing was positively and significantly correlated with student academic achievement. Five components of argumentative writing were predictors of success on student achievement tests: accuracy of the claim, relationship between claim and question, relationship between claim and evidence, use of multiple modes to represent an argument, and the degree to which writing style aligns with the writing type desired. Therefore, results from this study would allow teachers to modify their approaches to emphasize components of argumentative writing that can predict student academic achievement. Results from open-ended questionnaires reveal that students viewed argumentative writing as a tool that improves their conceptual understanding, advances their epistemic understanding of an argument, and can be applied in their future careers. Implications of this pedagogy for chemistry teaching and learning are discussed.

The skills and knowledge of the employers of chemists have been explored in varying degrees of specificity. Some studies have argued that the current university curriculum does not prepare students for modern industry adequately, while others have provided an overview of the job market for graduates with a bachelor's degree in chemistry. In order to stay relevant, the chemistry undergraduate course syllabi need to evolve constantly to meet the needs of the modern-day chemist. This study examines the specific technical skills and knowledge in job advertisements required by graduates with a bachelor's degree in chemistry to successfully transition to a workplace. A relatively new initiative in the chemistry department of the National University of Singapore, namely, the final year internship program, is also evaluated in this paper. Additionally, the chemistry undergraduate course syllabi of the universities and the most researched chemistry topics are examined. The aim of this study is to bridge the gap between chemistry departments and industries or research institutes.

Chemical waste should be reduced to minimize environmental pollution, and it is important that the amount of waste is minimized in chemistry teaching laboratories to reduce the negative impact on environment as well as the disposal costs of university. There are several ways to minimize the waste generated in chemistry teaching laboratories, namely, (1) elimination or reduction of the source of pollution, (2) recycling and reusing the chemicals, (3) treatment of waste to minimize its hazards, (4) the use of microscale chemistry, and (5) better management of chemical inventories in the laboratories. In this study, the common course syllabi and laboratory techniques of chemistry undergraduate experiments in universities are evaluated. The masses and volumes of chemical reagents used in the chemistry teaching laboratories of National University of Singapore (NUS) are quantified. Chemical waste reduction practices of the universities are examined, and a checklist is used to evaluate the current waste reduction practices in the chemistry teaching laboratories of NUS. Although there are existing practices that reduce the amount of chemicals used and waste generated in teaching laboratories, more effort could be done to improve the situation further.

Instruction in most STEM domains uses visuals to illustrate complex problems. During problem solving, students often manipulate and construct visuals. Traditionally, students draw visuals on paper and receive delayed feedback from an instructor. Educational technologies have the advantage that they can provide immediate feedback on students' visuals. This feedback allows students to learn visualization conventions and to learn new content knowledge. This paper presents a design-based research approach to develop visual tools for an educational technology for chemistry. In this research, three design tradeoffs emerged: (1) Which aspects of the drawing task should visual tools constrain? (2) How should visual tools account for variability in students' prior experiences? (3) How should the design of multiple visual tools be aligned so that students can easily transition between them? Our design-based research approach comprises three studies that address each of these design challenges in the context of chemistry visualizations. Our studies yield principles for the design of interactive visual tools for educational technologies.

An integrated and research-focused laboratory experiment is developed to introduce the "antenna effect" occurring in luminescent lanthanide complexes to students. Students synthesized a lanthanide metal-organic framework (Ln-MOF) with the formula of [Eu(BTPCA)(H O)]·2DMF·nH[Subscript 2]O (Eu-BTPCA, H[subscript 3]BTPCA = 1,1',1?-(1,3,5-triazine-2,4,6-triyl)tripiperidine-4-carboxylic acid) by the solvothermal method and characterized its structure by powder X-ray diffraction. They then measured the luminescence spectrum of Eu-BTPCA and compared it with that of EuCl[subscript 3]. Finally, students performed the luminescent sensing studies to metal ions. This experiment lets students gain the first-hand experience of solvothermal syntheses of MOFs and introduces essential scientific research approaches to students as well as exposes students to modern instrumental techniques for chemical research. Most importantly, through this experiment and its outcomes analyses, students can better understand the "antenna effect" and witness its application in metal ion luminescent sensing.

Three internally developed mobile apps, "3D Sym Op", "SM2 Chem" and "ARMolVis," available for free on both the Apple App Store and Google Play Store were evaluated in seven studies. Each study was a systematic process of Pre-Test, In-lecture App Demo, App Assisted Interactive Tutorials (AAITs) and/or Independent App Usage (IAU), followed by a Survey and Post-Test. Overall, the mobile apps were effective evident by the higher Post-Test vs. Pre-Test % increase for those who used the app more frequently compared to those who used the app rarely. Apps were most effective when used in AAITs with the Blended Learning approach. This approach requires the physical presence of both teacher and student, but with some element of student free play such as using the app to complete worksheets in pairs or groups.

High resolution isotope ratio mass spectrometry (HR-IRMS) is often used to measure the abundance of deuterium to verify the efficiency of isotope isolation of a cryogenic distillation column system. In order to achieve precise quantification of hydrogen isotope abundance by HR-IRMS, a fine tuning procedure was performed by using molecular hydrogen to optimize the source parameters, steering parameters and analyzer parameters. The mass resolution can reach 10 000 after tuning, which is high enough to separate all potential hydrogen and helium isotopes except for 3He+ and T+. The test results of peak center stability, peak top flatness, resolution and sensitivity stability showed that the performance of the mass spectrometer can meet the demand for hydrogen isotope analysis. The inlet pressure should be in the range of 4-33 Pa to obtain stable sensitivity, and the accelerating voltage of the ion source should not be less than 8 V because it is negatively correlated with the production rate of trimmers (H3+, D3+, H2D+ and HD2+ etc.). As the accelerating voltage decreasing, the production rate of trimers increases. Another key factor affecting the production rate of trimers is the inlet pressure, the square of which is proportional to the production rate of trimers. Therefore, optimizing the ion source parameters to obtain higher sensitivity is a better way than increasing the sample inlet pressure. On this basis, the equilibrium hydrogen isotope standards which are essential to obtain the sensitivity of each component of hydrogen isotopes were prepared by a self-made standard gas preparation device, and the sensitivity values of each component were corrected by pure gases and the self-prepared standard with verified compositions. The molecular leak rate for the inlet hole was determined by monitoring the pressure for H2 and D2 as a function of time as the gas leaked out, and the leak rate of the other components could be calculated using the leak rate of H2 or D2 because the leak rate is inversely proportional to the square root of the molar mass. Standard mixtures were analyzed to test precision and trueness of this method. The results showed that the measurement precision is better than 1% for samples with natural deuterium abundance and better than 0.5% for samples with medium to high abundance of deuterium. The measured values are in good agreement with the standard values. Compared to the low resolution mass spectrometry, this method is simple and reliable, does not need to resolve the mass overlap peak, and the accuracy of the measurement does not depend on the degree of hydrogen isotope balance in the sample.

A method of ultra-high performance liquid chromatography quadrupole electrostatic field Orbitrap mass spectrometry (UHPLC-Q/Orbitrap MS) was developed for rapid screening illegal additives in diet food. The efficacy of three extraction solvents for methanol, acetonitrile and acetonitrile containing 1% formic acid were evaluated for the extraction of illegal additives from green plums and jellies. Ultimately, acetonitrile is selected to extract illegally additives under ultrasonication. In order to achieve good separation of the additives by UHPLC in diet foods, four mobile phases were compared, including methanol (0.1% formic acid)-water (0.1% formic acid and 5 mmol/L ammonium acetate), acetonitrile (0.1% formic acid)-water (0.1% formic acid and 5 mmol/L ammonium acetate), acetonitrile-water (5 mmol/L ammonium acetate), acetonitrile-water. The effects of mobile phases and acidity levels on the chromatographic behavior of the additives were investigated, and acetonitrile-water containing 5 mmol/L ammonium acetate shows the best performance under appropriate gradient. Then, the MS data were acquired in Full MS/dd-MS2 mode on UHPLC-Q/Orbitrap MS with the matrix-matched external standard method for quantification. Based on the self-constructed database of illegal additives in diet foods, one unknown additive is detected in a diet food containing green plums and jelly. By characterizing the molecular ion peak, secondary fragment ion information, and isotopic information, the unknown compound is identified to be 4-chlorobisacetophenetidin, also an illegal additive, which was verified by computation of density functional theory and analysis of the standard substance. To validate the accuracy and reliability of the method, the limits of detection (LODs), the limits of quantification (LOQs), linear ranges, recoveries, relative standard deviations (RSDs) and matrix effect (ME) for eight compounds were determined. The LODs and LOQs of deacetylbisacodyl and bisacodyl are 0.001 and 0.005 mg/kg, respectively. The LODs and LOQs of other compounds are 0.05 and 0.1 mg/kg, respectively. The correlation coefficient (R2) is higher than 0.999. All of the compounds exhibit varying degrees of MEs from moderate to weak, and the recoveries is in the range of 71.02%-103.01% with the RSDs of 0.87%-13.24%. The approach was applied to diet food containing green plums and jelly. The 4-chlorobisacodyl are detected in 30% of the green plums, suggesting that this method is suitable for the rapid qualitative and quantitative analysis of illegal additives in diet food. It is also demonstrated that the established screening process plays a positive role in identifying potential risk substances. The combination of quantum chemistry computation and mass spectrometry provides a novel strategy for the identification of unknown additives in food.

Smoke aerosols contain many harmful substances and have become one of the major sources of indoor pollutants. The smoke aerosols released into the environment are easy to react with various oxidants presented in the room, namely the aging process of the smoke aerosol, which can produce secondary organic aerosols. The chemical composition of smoke aerosol is an important factor affecting its indoor aging process, but so far, the change behavior of the composition and particle size distribution of smoke aerosol during the aging process remains to be studied, and the aging analysis of novel tobacco products has not been reported. Therefore, the present study applied a house-made vacuum ultraviolet photoionization time-of-flight mass spectrometer to detect the chemical composition of the smoke aerosols produced by combustion cigarette, and new tobacco products, e.g., heat-not-burn tobacco products and e-cigarette, achieving the in-situ online characterization of their gas-phase and particulate-phase components. The results showed that the chemical composition of the smoke aerosols generated by the three types of tobacco products is significantly different, among which the component content and species abundance of the combustion cigarette are much greater than those of the novel tobacco products, and the overall signal intensity of combustion cigarette in the gas-phase and the particulate-phase is about 100 times and 10 times that of novel tobacco products, respectively. In addition, it was found that the particulate-phase mass spectra of novel tobacco products contain a large amount of glycerol, which is almost absent in combustion cigarette, and its intensity is even more than nicotine. The detected aerosol components contain many unsaturated compounds, which are easily oxidized in the environment and generate new ultrafine particles (UFPs). The Teflon chamber was used to simulate the aging process of the above three smoke aerosols with different O3 concentrations. The results of scanning mobility particle sizer showed that UFPs are generated in all of them. Corresponding to the results of photoionization mass spectrometry, the aging processes of the three smoke aerosols are completely different, in which the formation conditions of UFPs are related to the content and composition distribution of precursors. Specifically, the indoor concentration of O3 (observed in this experiment was 40 μg/m3) can promote the formation of UFPs with a geometric mean diameter of about 26 nm in the combustion cigarette, while the UFPs formation of novel tobacco products requires a higher concentration of O3 or a longer aging time. This is mainly facts that the whole composition concentration of the novel tobacco products is much lower than that of combustion cigarette, and the particulate-phase components contain a lot of glycerol. Due to the strong viscosity and encapsulation, glycerol may exist in the particulate-phase of the smoke aerosol in the form of coating other substances, such as nicotine, and further prevents the aging process of other substances, resulting in differences in particle size distribution. This study explains the reason of difference in UFPs formation of various smoke aerosols during the aging process and provides a basis for tobacco exposure risk assessment, which is expected to reveal the aging mechanism of smoke aerosols in the future.

Per- and polyfluoroalkyl substances (PFASs) are a collective term for various artificial fluorinated organic compounds. PFASs not only have hydrophilic functional groups and hydrophobic alkyl side chains, but also have fire resistance, high stability and durability, making them widely used in various industries. PFASs have the characteristics of high toxicity, persistence, bioaccumulation, and long-distance migration of persistent organic pollutants. Different types of PFASs have different harmful effects on biological organisms, and health risks are mostly concentrated in the liver, immune system, and reproductive system. At present, there are many detection methods reported for PFASs in the food and environmental fields, while few methods have been applied for the detection of PFASs in cosmetics. In this work, a method for rapid detection of PFASs in cosmetics was developed by QuEChERS (quick, easy, cheap, effective, rugged, and safe) pretreatment coupled with gas chromatography-quadrupole/time of flight mass spectrometry (GC-Q-TOF MS). Firstly, the extraction solvents, extraction methods, and purification agents were compared, the dosage of purification agents was optimized, and the matrix effect was examined. Eight kinds of volatile PFASs, including two perfluorooctanoic acid esters, four fluoro modified polyacrylates, and two fluoro modified siloxanes in the samples were extracted with 10 mL ethyl acetate, dehydrated by 1 g anhydrous sodium sulfate, and purified by 100 mg graphitized carbon black (GCB) and 50 mg silica gel powder (Si). Target compounds were separated by DB-5MS capillary column (30 m×0.25 mm×0.25 μm), and the mass spectrum was acquired under full scan mode of EI ion source with using external standard method for quantification. The result showed that the work curves of the 8 compounds have good linear relationship, and the correlation coefficient (R2) is greater than 0.997 6 in the range of 5.0-1 000 μg/L. The limits of detection are 20.0 and 200.0 μg/kg, and the limits of quantification are 50.0 and 500.0 μg/kg. The average recoveries at three levels range from 81.4% to 112%, and the relative standard deviations are 1.09%-7.63% (n=6). In total, 105 cosmetic samples purchased from Guangzhou supermarkets and online e-commerce were tested using this method, 8:2FTMAc in 2 samples are detected with 668, 1 004 μg/kg, respectively, indicating that cosmetic samples pose a risk of PFASs contamination, should be taken seriously by regulatory authorities and consumers. This method is high efficiency, sensitive and accuracy, which can provide important basis for the rapid detection and quality control of PFASs compounds in cosmetics.

A pyridine–tricarboxylic acid, 4-(6-carboxy-pyridin-3-yl)-isophthalic acid (H3cpia), was used as a versatile building block to synthesize three novel coordination polymers under hydrothermal conditions and formulated as [Mn8(μ3-Hcpia)2 (μ6-cpia)4(Hbiim)2(H2O)6]n·6nH2O (1), [Cu3(μ4-cpia)2(bipy)2(H2O)2]n·4nH2O (2), and [Ni3(μ3-cpia)2(dpe)3(H2O)2]n·4nH2O (3). Three supporting ligands, 2,2′-biimidazole (H2biim), 2,2′-bipyridine (bipy), and 1,2-di(4-pyridyl)ethane (dpe), were used in the synthesis. The structures of the studied products 1–3 varied significantly, ranging from a 1D chain (2) to 2D sheets (1 and 3). Furthermore, these compounds were evaluated as heterogeneous catalysts for the Henry reaction, achieving high product yields under optimized conditions. In addition, we investigated various reaction parameters and substrate scopes, and assessed the feasibility of catalyst recycling. This thorough investigation’s results highlight the versatility of H3cpia as a tricarboxylate building block in the formation of functional coordination polymers.

A method of gas chromatography-mass spectrometry (GC-MS) was established to determine the migration of dibutyl sebacate, dioctyl sebacate, diisooctyl sebacate, decanedioic acid bis(2,2,6,6-tetramethyl-4-piperidinyl)ester in water-based, acidic and alcoholic food simulants, and olive oil and chemical alternative solvents. The 95% ethanol and isooctane chemical substitution solutions were directly analyzed by GC-MS. The olive oil samples were extracted with acetonitrile followed by QuEChERS purification, and then analyzed by GC-MS. Other simulants (water, 4% acetic acid, 10% ethanol, 20% ethanol, and 50% ethanol) were extracted with n-hexane and then determined by GC-MS. The results showed that the method is well performed under optimized conditions, with the correlation coefficient (r2) greater than 0.995. The limits of detection and the limits of quantitation of the four sebacic acid ester compounds in water, 4% acetic acid, 10% ethanol, 20% ethanol, 50% ethanol, 95% ethanol, isooctane, and olive oil simulants are 0.1-0.2 mg/kg, 0.3-0.5 mg/kg, respectively. Migration experiments on plastic samples were conducted, and spiking experiments at three concentration levels of 0.30, 2.0, 4.0 mg/kg in water, 4% acetic acid, 10% ethanol, 20% ethanol, 50% ethanol, 95% ethanol, and isooctane food simulants, and three concentration levels of 0.50, 2.0, 4.0 mg/kg in olive oil food simulants were carried out. The spiking recoveries range from 92.5% to 108%, and the relative standard deviations (RSDs) are 2.4%-8.8%. The method solves the problem that decanedioic acid bis(2,2,6,6-tetramethyl-4-piperidinyl)ester cannot be extracted into n-hexane in 4% acetic acid by adjusting pH value using ammonium hydroxide, the optimal pH range was determined by comparing the responses of four targets at different pH values. QuEChERS was firstly used for migration experiments of sebacic acid esters in food contact materials to solve the turbidity and partial oil precipitation of olive oil simulants in the concentration process after extraction. By optimizing the QuEChERS filling material, the interference of organic acids, fatty acids, sugar and other impurities on the targets were reduced, producing greater separation effect of the targets. The separation efficiency of four chromatographic columns with different polarity was compared, and the DB-17HT column was selected to detect the four sebacic acid esters simultaneously. Plastics such as polypropylene, polyethylene terephthalic acid terephthalate, polyvinyl chloride, composite membranes, paper cups, recycled PET and recycled PVC were collected and migration experiments were carried out, the migration of sebacic acid esters in these plastics materials was investigated. This method is highly sensitive, precise, and accurate, fully meeting the requirement for determining the migration of the sebacic acid esters in food contact materials and their products.

The proposed experiment can help students to understand the factors involved in the stability of gold nanoparticles (Au NPs) by exploring the adsorption interaction between Au NPs and various substances. The students in this study found that the surface plasmon resonance band of Au NP solutions underwent a red shift (i.e., from 520 to 650 nm) because of NaCl-induced aggregation caused by the elimination of the repulsive electrostatic force. In addition, a sufficient amount of bovine serum albumin molecules (29.4 nM) adsorbed on the surface of Au NPs (1.8 nM) through electrostatic interactions provides steric barriers that hinder electrolyte-induced aggregation. This experiment was performed in the fall 2014 semester to improve the recognition of nanoscale science and engineering concepts of undergraduates.

In the current study, the CN-CD30V10A battery tester, K-type temperature sensor, and RS485 are utilized to perform charging and discharging tests on the Panasonic 21,700 lithium-ion battery at various rates. The voltage and temperature changes are measured in real-time, with the data transmitted to the computer via RS485. Then a micro-thermal resistance method is proposed to calculate the equivalent thermal resistance of the cell core along the axial positive and negative poles, as well as along the radial outer circumference surface under anisotropic conditions. Based on the experimental results and the equivalent thermal resistance, an electrothermal coupling model is established for battery internal temperature estimation, taking into account anisotropy and temperature effects on heat transfer. Through the integration of the model and externally measured temperature, the internal temperature is accurately estimated. Moreover, the proposed model (Root-Mean-Square Error, RMSE=0.329) exhibits a significant improvement in accuracy compared to equivalent circuit model (RMSE=1.08), extended Kalman filter (RMSE=0.95), network extended Kalman filter (RMSE=0.58), and neural network unscented Kalman filter (RMSE=0.61). Specifically, the model achieves an approximately 76 % to 228 % reduction in RMSE compared to these methods.

Grain of high yield and quality is needed worldwide due to the needs of a rapidly increasing human population. However, diseases caused by some stubborn types of phytopathogenic bacteria can limit the health and yields of crops. Even worse, conventional commercial bactericides have limited efficacy against such diseases. Therefore, exploring some efficacious bactericidal alternatives is urgently needed. In this work, a new type of 3-(piperazin-1-yl)propan-2-ol modified carbazole derivatives was synthesized and assessed for their bactericidal activity. Among them, compound B16 was the optimal active molecule, giving the EC50 values of 3.11 (Xanthomonas oryzae pv. oryzae), 3.20 (Xanthomonas axonopodis pv. citri) and 3.54 μg/mL (Pseudomonas syringae pv. actinidiae). Pot experiments revealed compound B16 to be able to control rice bacterial leaf blight. Some biochemical assays illustrated that our designed compounds could destroy the integrality of bacterial cell membranes and thereby leading to leaking the intracellular protein. These findings may be regard as a reference for the design of novel membrane-targeting antimicrobial agents for managing stubborn plant bacterial diseases.

To study the effect of various extractants on the structure of peat humic acid, peat humic acid was extracted using [NH.sub.3]*[H.sub.2]O, [Na.sub.2][CO.sub.3], [NaHCO.sub.3], and [Na.sub.2][SO.sub.3] via alkali-extraction and acid-precipitation methods. The extracted peat humic acid was characterized using ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and fluorescence (FL) spectroscopy. The results showed that the extractants had negligible effects on the content of peat humic acids. [Na.sub.2][CO.sub.3] was found to be the most effective extractant for isolating humic acids from peat, with the highest content of 66.20% and a yield of 32.67%. Moreover, among the extractants used, [NH.sub.3]*[H.sub.2]O resulted in humic acids with the highest aromaticity, and [Na.sub.2][SO.sub.3] yielded humic acids with higher number of hydroxyl groups. [NaHCO.sub.3] yielded humic acids with the most aliphatic ether and lowest aromaticity. [Na.sub.2][CO.sub.3] was the best extractant for isolating humic acids from peat, having the highest content, lowest degree of aromatic polymerization, and highest number of carboxylic acids., Plant organisms gradually form peat through the slow de com position of anaerobic microorganisms under excessive water and insufficient air environments (1). Peat originates from mosses and woody and herbaceous [...]

The latest review published in Nature Reviews Drug Discovery by Michael W. Mullowney and co-authors focuses on the use of artificial intelligence techniques, specifically machine learning, in natural product drug discovery. The authors discussed various applications of AI in this field, such as genome and metabolome mining, structural characterization of natural products, and predicting targets and biological activities of these compounds. They also highlighted the challenges associated with creating and managing large datasets for training algorithms, as well as strategies to address these obstacles. Additionally, the authors examine common pitfalls in algorithm training and offer suggestions for avoiding them.

Multi-level adaptation in end-user development (EUD) is an effective way to enable non-technical end users such as educators to gradually introduce more functionality with increasing complexity to 3D virtual learning environments developed by themselves using EUD approaches. Parameterization, integration, and extension are three levels of adaptation ranging from straightforward to complex in terms of what end users have to understand in order to develop functional software applications, all within reach of end users without special training on programming. A 3D educational application EUD system prototype, "iVirtualWorld," has been expanded to support 3D virtual chemistry experiments generation using these three levels of EUD adaptation. An evaluation has been conducted on 18 participants from the education domain, and the results confirmed ease-of-learn, ease-of-use, and usefulness of this solution. Contributions of this paper are: (1) a paradigm for applying EUD technologies in 3D virtual learning environment creation; (2) an easy-to-use tool for educators to build customized virtual chemistry experiments; and (3) empirical assessment data for the multi-level adaptation solution.