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There is a long tradition of teaching science through inquiry, with broad agreement about the form it should take. Students should investigate researchable questions; gather and analyse data; and develop and represent evidence-based claims. Authoritative teacher or textbook representations are generally used to guide this learning (Buckley & Boulter, 2000; Bybee, 1997; Furtak et al., 2012; Sell et al., 2006). Parallel to this approach, teachers have also guided students to construct, review and refine their own representations, leading to learning gains. However, this student representation construction approach poses new challenges for teachers. The teacher is expected to elicit and guide students' reasoning about their own represented claims as an orientation to understanding and learning scientific forms of reasoning and their representation. In this paper, drawing on our initial account of this pedagogy, we aim to clarify further this approach's rationale and teacher strategies and underlying purposes in key early stages of exploration in the topics of chemistry and mathematics with a Grade 5 class. An interdisciplinary focus was used to guide students' learning about the science concepts of states of matter, evaporation and the mathematical concepts of formal and informal measurement and data representation. Analysed data included video capture of the teacher's guidance of tasks and classroom discussion, student artefacts and teacher and student interviews. We identify how the teacher framed the task, oriented student inquiry and guided evaluation of students' representations through implicit and explicit instruction.

The microscopic composition of substances is a piece of essential but abstract knowledge in chemistry. Junior high school students may experience difficulty in mental representation when learning micro concepts, which leads to problems such as unsatisfactory academic performance and low learning motivation. Augmented reality (AR) is an optimal choice for presenting abstract concepts and invisible phenomena. Consequently, this study developed an AR application including three-layer experiential learning activities and integrating multiple external representations (text, pictures, 3D models, operations, etc.). To assess the effect of the AR application on students' knowledge gains, learning motivation, and technology perception, an experiment was conducted with 95 ninth-grade students aged 13-15 years who were randomly assigned to two groups (AR and non-AR). The results show that the AR application helped increase students' knowledge gains. Although there was no significant difference in the retention test between the two groups, scores on the transfer test were significantly higher for the AR group than for the non-AR group. Moreover, the AR application significantly improved students' motivation to learn. Finally, students had a positive perception of AR technology.

Scientific methods have received widespread attention in recent years. Based on the analytical framework derived from Brandon's matrix consisting of four categories of scientific methods, this paper aims to conduct a content analysis to examine how the diversity of scientific methods is represented in college entrance chemistry examination papers from three exam boards in China. It was found that the percentages of the four categories of scientific methods in the examination papers varied significantly from each exam board, highlighting an imbalanced representation of scientific methods. Furthermore, among the four categories of scientific methods, non-manipulative parameter measurement (Non-MPM) accounted for the largest proportion in each examination paper, while the proportion of manipulative hypothesis testing (MHT) was very small, indicating that the practical chemistry items in China are less experimental. At the end of this paper, the implications of the findings and suggestions for further studies are discussed.

Medicinal chemistry, as the core curriculum of the pharmaceutical engineering major, contains complex knowledge systems and scattered knowledge points. A medicinal chemistry course covers more than 50kinds of drugs divided into 11 categories including antibiotics, antiparasitic drugs, anesthetics, nonsteroidal anti-inflammatory drugs, and nervous system drugs. This places a substantial learning burden on students and seriously affects their learning interest and initiative. On the basis of the innovative curriculum reform of "student-centered" learning and with the aim of improving the quality of instruction provided in medicinal chemistry courses, a novel "student-centered team-based learning" (SCTBL) method was developed to cope with these challenges on the basis of our long-term teaching experience. This paper introduces the essence of the team-based learning method and explores the application of SCTBL in the process of teaching medicinal chemistry, which consists of three stages: preclass, in-class, and postclass. The results show that introducing the SCTBL method into medicinal chemistry instruction is conducive to improving students' learning enthusiasm and initiative, which is of great significance to the development of medicinal chemistry education.

Representations constitute an important part of chemistry knowledge. This paper revisits the notion of the term, symbolic, in the chemistry triangle proposed by Johnstone using the theoretical lens of social semiotics. In doing so, this paper proposes a framework of chemistry learning that highlights representational re-description and coordination as key mechanisms for facilitating connections among the three domains of knowledge: chemical phenomenon (perceptual-experiential level), macroscopic (theoretical-descriptive level) and submicroscopic (theoretical-explanatory level). This paper illustrates how this framework can be used to explore student meaning making of changes of state by examining students' interactions with the phenomena of melting and boiling and with the multiple representations of the phases of matter introduced in the classroom. The findings revealed the opportunities and challenges which emerged from student meaning making with multiple representations in the process of developing an understanding of the submicroscopic view of phase change. It also highlighted the support needed to facilitate such meaning making through representational re-description and coordination in order for students to develop a deep understanding of the logical connections between the particular model and the macroscopic patterns of the observed phenomena.

In this work, we introduce the VR[superscript 2]E[superscript 2]C system for Virtual Reality Remote Education for Experimental Chemistry. It aims to increase scientific literacy about remote education of theoretical and experimental chemistry among the public and high school students. It provides a laboratory option for students with disabilities who are keen on chemistry experiments but have limited mobility. VR[superscript 2]E[superscript 2]C provides three modes to accomplish the training: users can choose to control the intelligent robot to finish the experimental operations by instruction or choose to watch the experiments automatically conducted by VR[superscript 2]E[superscript 2]C. The experimental results can be delivered to users in real time or later. This system provides remote education for safe and high fault-tolerant experimental topics, demonstrating how the latest VR and robotics technology could benefit traditional chemical education.

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 Joint Safety Team (JST) was conceived in 2012 by the Departments of Chemical Engineering and Materials Science and Chemistry at the University of Minnesota and the Dow Chemical Company as a model student-led safety organization. The JST initiative was aimed at improving academic safety through four core areas: compliance, awareness, resources, and education. Since its inception, the JST has taken great strides to develop a culture of peer-led safety at Minnesota. We describe the evolution of the structure of the organization over the last 8 years and the innovative methodologies employed by the JST to educate and evaluate safety in academic laboratories. The continuous efforts of the student members of the JST have enabled the organization to be recognized as a leader in peer-to-peer safety. The Minnesota model of "inform and reform" is now being adopted at other academic institutions to develop safety organizations emulating the JST.

This study examined participatory simulation-based learning of teaching in a virtual reality (VR) supported learning environment and its affordance for alternative perspectives taking. This VR-supported, embodiment-integrated learning environment is designed to enable collaborative and contextualized microteaching practicing by university teaching assistants. A total of 42 chemistry teaching assistants participated in a 3-hour teaching training session, during which they were randomly assigned to a VR-supported simulation group and a live simulation group. The study found teaching knowledge development for all participants after simulation-based training. The live simulation participants better performed in the post-session knowledge test than the VR simulation participants. Qualitative data indicated a multitude of challenges and opportunities in VR simulation-based learning, including a concurrent, yet, inequivalent experience of the "diving-in" and "stepping-out" learning perspectives during virtual collaborative role-playing in a hybrid learning space.

We developed a comprehensive training module for the undergraduates majoring in chemical education with a simple microfluidic experiment. The students were required to read a scientific reference offered by the instructor, then design and implement a microfluidic experiment for real sample analysis by making some modifications to the method described in the reference. Finally, the students were required to evaluate the analytical results with a standard method and write an experimental report. This reading-designing-implementing-evaluating-writing (RDIEW) module aims to enhance the students' experimental skills as well as their abilities at designing experiments and reading English scientific literature. More importantly, the concept of microfluidic analysis was successfully introduced to the undergraduates majoring in chemical education by this training module, which may facilitate the introduction of microfluidic devices to chemistry courses at high schools. This 1 week (3 h per day) module was developed for the undergraduates majoring in chemical education at the sixth semester. The feedback from the students indicated that the learning objectives of this training module were met.

Lock-in amplifiers (LIAs) are commonly used in chemistry laboratories to improve noise-to-signal ratios. Constructing and testing a suitably designed LIA provide undergraduate students with an excellent opportunity to learn about theory, construction, and applications of LIA. In particular, students can learn about time-dependent behavior and various components, from resistors (R) and capacitors (C) to packaged microchips such as demodulators and phase shifters. We provide here design and performance characteristics of a two- (Vx, Vy) channel LIA based on balanced modulator/demodulators (AD630). The LIA includes configurable resistor-capacitor (RC) high-pass and low-pass filters, various op-amp circuits, and a phase-shifter. Various configurations of resistors/capacitors, as well as salt solutions and isopropanol/pentane mixtures, are used as samples to measure conductance or capacitance to test both V[subscript x] and V[subscript y] channels of the LIA. The results are consistent with behaviors expected theoretically. The LIAs yield excellent noise/signal ratios with peak-to-peak values that are <0.2% and that compare favorably with commercial LIA performance.

This communication describes a method to detect aluminum in gastric drugs by the naked eye using a microfluidic paper-based analytical device ([mu]PAD). Aluminum ions react with chrome azurol S (CAS) and cetyltrimethylammonium bromide (CTAB) to form a colored complex, which generates a colored band on the [mu]PAD. A printed ruler can be used to measure the length of the colored band on an individual paper channel for the quantification of an aluminum ion. The [mu]PAD system was designed for use in a modern instrumental analysis course taken by students majoring in Food Quality and Safety. This analytical protocol could also be modified to be used as a demonstration or laboratory experiment in a high school chemistry course with some simplifications to the procedures.

We described a simple method for detection of Fe on a thread-based analytical device. Fe reacts with 1,10-phenanthroline to form a colored band on a cotton thread; the length was measured to quantify the contents of Fe using a ruler. This method has the advantages of easy operation, low cost, easy fabrication, and reduced sample/reagent consumption. Furthermore, this method is free of any electronic equipment such as camera and digital scanner. These features make this method suitable as a laboratory experiment in universities and colleges. This laboratory experiment is designed as one of selected experiments of the Comprehensive Chemistry Experiment course for the students majoring in chemistry, for the sixth and seventh semester. The students enjoyed fabricating the thread-based analytical device and used it to detect the contents in unknown samples. This laboratory experiment could be completed within 3 h.

Abstract Fungal natural products from various species often feature hydroxamic acid motifs that have the ability to chelate iron. These compounds have an array of medicinally and ecologically relevant activities. Through genome mining, gene deletion in the host Aspergillus terreus, and heterologous expression experiments, this study has revealed that a nonribosomal peptide synthetase (NRPS) TamA and a specialized cytochrome P450 monooxygenase TamB catalyze the sequential biosynthetic reactions in the formation of terramides A-C, a series of diketopiperazines (DKPs) with hydroxamic acid motifs. Feeding experiments showed that TamB catalyzes an unprecedented di-hydroxylation of the amide nitrogens in the diketopiperazine core. This tailoring reaction led to the formation of two bidentate iron-binding sites per molecule with an unusual iron-binding stoichiometry. The structure of the terramide A-Fe complex was characterized by liquid chromatography-mass spectrometry (LC-MS), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and electron paramagnetic resonance spectroscopy (EPR). Antimicrobial assays showed that the iron-binding motifs are crucial for the activity against bacteria and fungi. Murine infection experiments indicated that terramide production is crucial for the virulence of A. terreus and could be a potential antifungal drug target.

Nano-ZnO/transition metal composites (NZTC) were prepared via sol-gel method where transition metal (Cu2+, Ag+, Co2+ and Ni2+) and ZnSO4 were used as the substrate. NZTC was characterized using scanning electronic microscope (SEM), ultraviolet-visible spectrophotometer (UV), fluorescence spectrophotometer (XRF), infrared spectrometer (IR), and so on. The photocatalytic degradation behaviors of nano-ZnO and NZTC for formaldehyde in gas and solution were investigated. The results indicated that nano-ZnO and NZTC could achieve the degradation of formaldehyde by photocatalytic process, and the degradation rates were up to 43.75% and 67.2% in gas and solution, respectively, thus thereby leading to good application prospects in the degradation of organic compounds.

The development and creation of innovative therapeutic supplements and medications with extraordinary efficacy for addressing severe diabetes are of utmost importance to both developing and developed nations. A bio-inspired method has been documented for producing copper nanoparticles (CuNPs) using Pistacia atlantica leaf extract as a natural stabilizing agent. This approach is applicable, easy, and environmentally friendly, as it avoids using any toxic or harmful reagents. The CuNPs that were synthesized through biological processes underwent characterization using sophisticated physicochemical methods such as energy-dispersive X-ray spectroscopy, transmission electron microscopy, field emission-scanning electron microscopy, and Fourier-transformed infrared spectroscopy. It is confirmed that CuNPs exhibit a spherical structure, with an average size ranging from approximately 30 to 70 nm. Diabetes was induced in vivo through a fructose-enriched diet combined with streptozotocin. Half the subjects were administered CuNPs (100 µg/kg) via oral gavage. In contrast to the animals that were given regular food, the diabetic animals revealed an increase in serum fasting glucose level and a decrease in glucose tolerance. The administration of CuNPs had a significant impact on reducing glucose intolerance and fasting hyperglycemia. Additionally, it helped alleviate the negative effects of diabetes on cardiac output and work. Furthermore, utilizing CuNPs effectively hindered the rise in cardiac signal transducer and activator of transcription 3-phosphorylation caused by diabetes. The findings from this investigation provide evidence of the therapeutic benefits of CuNPs in mitigating diabetes-induced cardiac dysfunction in rats.

The volatile components of Citri Grandis Exocarpium from Huazhou (CGEH) and Guangxi (CGEG) were analyzed by portable gas chromatography-mass spectrometry (GC-MS) and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOF MS) combined with headspace solid-phase microextraction (HS/SPME). Due to its limited separation ability, the portable GC-MS can identify only 8 chemicals in CGEH and 4 chemicals in CGEG and is not able to determine any marker compounds which can distinguish CGEH over CGEG. While the merit of GC×GC-TOF MS is strong separation ability, allowing the identification of 304 chemicals in CGEH and CGEG, of which 261 chemicals are reported for the first time. Among them are 52 compounds only detected in CGEH, 81 ones unique in CGEG, and 171 detected in both CGEH and CGEG. The volatile components in CGEH and CGEG are classified into 17 and 19 types, respectively. The contents of alkene aromatics, hydrocarbons and alcohols in both CGEH and CGEG are relatively high. The principal component analysis (PCA) and orthogonal partial least squares (OPLS-DA) were further performed on the MS data obtained by GC×GC-TOF MS. The results indicated that there is basically no difference from different batches of fruits in the same region, while have obvious differences between CGEH and CGEG. Among these different components, 10 compounds including 3,4-diethyl-1,1'-biphenyl, 1-methyl-4-(1-methylethenyl)-1,2-cyclohexanediol, 1-dodecanol, α-ethylidene-benzeneacetaldehyde, 3,8-dimethyl-undecane, tetradecanal, 2-methyl-tridecane, 5-methyl-2(5H)-furanone, tetraethylene glycol, sabinol in CGEH are screened out with the values of Pearson correlation coefficient |p(corr)|>0.9, |p|>0.06 and variable influence on projection (VIP) value>1.1. On the other hand, several marker compounds, such as cedrane, hibaene, 1,3,5-tris(methylene)-cycloheptane, (E)-longipinane, 1,1,6,6-tetramethylspiro[4.4]nonane, 2-(4a,8-dimethyl-1,2,3,4,4a,8a-hexahydro-2-naphthalenyl)-2-propanol, γ-gurjunene, [1S-(1α,4α,7α)]-1,2,3,4,5,6,7,8-octahydro-1,4,9,9-tetramethyl-4,7-methanoazulene, (2R,5S)-2-methyl-5-(prop-1-en-2-yl)-2-vinyltetrahydrofuran, copaene, spathulenol, β-elemene, sativene, N-[4-bromo-n-butyl]-2-piperidinone, eremophilene, 10α-eremophilane, oleyl alcohol, trifluoroacetate, and selinane are picked up in CGEG. These results proved that GC×GC-TOF MS can identify markers of Citri Grandis Exocarpium, while portable GC-MS can not. These markers can help to distinguish CGEH from others and provide references to quality evaluation of Citri Grandis Exocarpium.

Abstract Background Facing the significant challenge of overcoming drug resistance in cancer treatment, particularly resistance caused by mutations in epidermal growth factor receptor (EGFR), the aim of our study was to identify potent EGFR inhibitors effective against the T790M/C797S/L858R mutant, a key player in resistance mechanisms. Methods Our integrated in silico approach harnessed machine learning, virtual screening, and activity evaluation techniques to screen 5105 compounds from three libraries, aiming to find candidates capable of overcoming the resistance conferred by the T790M and C797S mutations within EGFR. This methodical process narrowed the search down to six promising compounds for further examination. Results Kinase assays identified three compounds to which the T790M/C797S/L858R mutant exhibited increased sensitivity compared to the T790M/L858R mutant, highlighting the potential efficacy of these compounds against resistance mechanisms. Among them, T001-10027877 exhibited dual inhibitory effects, with IC50 values of 4.34 µM against EGFRT790M/C797S/L858R and 1.27 µM against EGFRT790M/L858R. Further investigations into the antiproliferative effects in H1975, A549, H460 and Ba/F3-EGFRL858/T790M/C797S cancer cells revealed that T001-10027877 was the most potent anticancer agent among the tested compounds. Additionally, the induction of H1975 cell apoptosis and cell cycle arrest by T001-10027877 were confirmed, elucidating its mechanism of action. Conclusions This study highlights the efficacy of combining computational techniques with bioactivity assessments in the quest for novel antiproliferative agents targeting complex EGFR mutations. In particular, T001-10027877 has great potential for overcoming EGFR-mediated resistance and merits further in vivo exploration. Our findings contribute valuable insights into the development of next-generation anticancer therapies, demonstrating the power of an integrated drug discovery approach.

​​​​​​​This study compares aerosol mixing-state parameters obtained via simultaneous measurements using DMA–CCNC, H(/V)TDMA, and DMA–SP2, shedding light on the impacts of primary aerosol emissions and secondary aerosol (SA) formation. The analysis reveals significant variations in mixing-state parameters among different techniques, with VTDMA and DMA–SP2 indicating that non-volatile particles mainly stem from black carbon (BC)-containing aerosols, while a substantial proportion of nearly hydrophobic aerosols originates from fossil fuel combustion and biomass-burning emissions. Synthesizing the results, some nearly hydrophobic BC-free particles were found to be cloud condensation nuclei (CCN)-inactive under the measured supersaturated conditions, likely from fossil fuel combustion emissions, while others were CCN-active, linked to biomass-burning emissions. Moreover, BC-containing aerosols emitted from fossil fuel combustion exhibit more external mixing with other aerosol components compared to those from biomass burning. Secondary nitrate and organic aerosol formation significantly affect aerosol mixing states, enhancing aerosol hygroscopicity and volatility while reducing heterogeneity among techniques. The study also highlights distinct physical properties of two resolved secondary organic aerosol factors, hinting at their formation through different mechanisms. These findings underscore the importance of comparing aerosol mixing states from different techniques as a tool for understanding aerosol physical properties from different sources and their responses to SA formation, as well as aiding in the exploration of SA formation mechanisms.

Non-methane hydrocarbons (NMHCs) in the marine atmosphere have been studied extensively due to their important roles in regulating atmospheric chemistry and climate. However, very little is known about the distribution and sources of NMHCs in the lower atmosphere over the marginal seas of China. Herein, we characterized the atmospheric NMHCs (C2–C5) in both the coastal cities and the marginal seas of China in the spring of 2021, with a focus on identifying the sources of NMHCs in the coastal atmosphere. The NMHCs in urban atmospheres, especially alkanes, were significantly higher compared to those in the marine atmosphere, suggesting that terrestrial NMHCs may be an important reservoir/source in the marine atmosphere. A significant correlation was observed between the alkane concentrations and the distances from sampling sites to the nearest land or retention of air mass over land, indicating that alkanes in the marine atmosphere are largely influenced by terrestrial inputs through air mass transport. For alkenes, a greater impact from oceanic emissions was determined due to the lower terrestrial concentrations, short atmospheric lifetime, and substantial sea-to-air fluxes of alkenes compared to alkanes (489 ± 454 vs. 129 ± 106 nmol m−2 d−1). As suggested by the positive matrix factorization, terrestrial inputs contributed to 89 % of alkanes and 69.6 % of alkenes in Chinese marginal seas, subsequently contributing to 84 % of the ozone formation potential associated with C2–C5 NMHCs. These findings underscore the significance of terrestrial outflow in controlling the distribution and composition of atmospheric NMHCs in the marginal seas of China.

Nonmethane volatile organic compounds (NMVOCs) are important precursors of ozone (O3) formation under sufficient nitrogen oxide conditions. Understanding the characteristics and emission sources of NMVOCs, as well as the relationship between NMVOCs and O3, is of great significance for effective O3 pollution control. In this study, continuous online monitoring of NMVOCs was carried out in Zhengzhou, Henan, from 1–30 June. Furthermore, the study provided recommendations for strategies aimed at reducing O3 formation. During the observation period, the concentration of total NMVOCs (TNMVOCs) varied from 9.9 to 60.3 ppbv, with an average of 22.8 ± 8.3 ppbv. The average concentration of TNMVOCs during O3 pollution events was higher than on clean days. Six major sources of NMVOCs were identified using the positive-matrix-factorization model. Vehicular exhausts (28 %), solvent usage (27 %), and industrial production (22 %) were the main sources. We explore the O3–precursors relationship and propose observation-oriented O3 control strategies. The results of the relative incremental reactivity (RIR) and the Empirical Kinetics Modeling Approach show that Zhengzhou was under an anthropogenic volatile organic compound (AVOC)-limited regime. NMVOCs had the largest RIR value, while NOx exhibited a negative RIR value. It is noteworthy that the sensitivity of O3 formation to biogenic volatile organic compounds (BVOCs) was greater than that to AVOCs. Considering the reduction effect, it is recommended that the ratio of AVOCs to NOx be maintained at no less than 3:1 to effectively reduce O3 formation.

The reaction process of copper-aluminum displacement in agar gel was observed at the microscopic level with a stereomicroscope; pine-like branches of copper crystals growing from aluminum surface into gel at a constant rate were observed. Students were asked to make hypotheses on the pattern formation and design new research approaches to prove their hypotheses. Results of the experiments designed by students well proved the existence of microcells in reaction system, which caused continuous growth of copper branches. The whole experimental teaching process motivated students by stimulating their interest and enthusiasm.

Dust significantly influences global weather and climate by impacting the Earth's radiative balance. Based on reanalysis datasets, this study explores how the North Atlantic Oscillation (NAO) and El Niño–Southern Oscillation (ENSO) during winter impact dust activities in North China in the following spring. It is found that both the NAO and the ENSO significantly affect dust activities in North China, especially during their negative phases. When both are in their negative phases, their combined impact on dust activities exceeds that of each factor individually. The previous winter's NAO notably affects sea surface temperatures (SSTs) in the North Atlantic, associated with an anomalous tripole SST pattern. These SST anomalies persist into the following spring due to their inherent persistence, inducing an anomalous atmospheric teleconnection wave train that influences dust activities in North China. The ENSO, on the one hand, directly impacts dust activities in North China by modulating circulation over the western North Pacific. Moreover, the ENSO enhances the NAO's effect on North Atlantic SST, which explains the synergistic effects of the ENSO and NAO on dust activities in North China. This study elucidates the combined role of the NAO and ENSO in influencing dust activities in North China, providing one-season-ahead signals for predicting spring dust activities in North China.

Amines and aminiums play an important role in particle formation, liquid-phase reactions, and climate change and have attracted considerable attention over the years. Here, we investigated the concentrations and compositions of aminiums in PM2.5 in 11 Chinese cities during the winter, focusing on the characteristics of aminiums during the polluted days and the key factors influencing aminium outbreak. Monomethylaminium was the dominant aminium species in most cities, except Taiyuan and Guangzhou, followed by dimethylaminium. Diethylaminium dominated the total aminiums in Taiyuan and Guangzhou. Thus, the main amine sources in Taiyuan and Guangzhou were significantly different from those in other cities. The concentrations of the total aminiums (TAs) in most cities increased significantly during the polluted days, while relatively weak aminium outbreaks during the polluted days occurred in Xi'an and Beijing. Additionally, the concentrations of TAs in Xi'an and Beijing were insignificantly correlated with those of PM2.5 and the major acidic aerosol components, while the opposite pattern was observed in nine other cities. Thus, acid–base chemistry was significantly associated with the formation of aminiums in PM2.5 in all cities, except Xi'an and Beijing. Based on the sensitivity analysis of the aminiums : ammonium ratio to ammonium changes, as well as excluding the effects of relative humidity and atmospheric oxidation, we proposed the possibility of the competitive uptake of ammonia versus amines on acidic aerosols or the displacement of aminiums by ammonia in Xi'an and Beijing (constraining aminium outbreaks). Overall, this study deepens the understanding of the spatiotemporal differences in aminium characteristic and formation in China. However, the uptake of amines on particles to form aminiums and the relevant influencing factors require further mechanistic research.

Abstract Multi-functional cysteine-targeting covalent warheads possess significant therapeutic potential in medicinal chemistry and chemical biology. Herein, we present novel unsaturated and asymmetric ketone (oxazolinosene) scaffolds that selectively conjugate cysteine residues of peptides and bovine serum albumin under normal physiological conditions. This unsaturated saccharide depletes GSH in NCI-H1299 cells, leading to anti-tumor effects in vitro. The acetyl group of the ketal moiety on the saccharide ring can be converted to other carboxylic acids in a one-pot synthesis. In this way, the loaded acid can be click-released during cysteine conjugation, making the oxazolinosene a potential multifunctional therapeutic agent. The reaction kinetic model for oxazolinosene conjugation to GSH is well established and was used to evaluate oxazolinosene reactivity. The aforementioned oxazolinosenes were stereoselectively synthesized via a one-step reaction of nitriles with saccharides and conveniently converted into a series of α, β-unsaturated ketone N-glycosides as prevalent synthetic building blocks. The reaction mechanisms of oxazolinosene synthesis were investigated through calculations and validated with control experiments. Overall, these oxazolinosenes can be easily synthesized and developed as cysteine-targeted covalent warheads carrying useful click-releasing groups.

The temperature trend in the mesosphere and lower-thermosphere (MLT) region can be regarded as an indicator of climate change. Using temperature profiles measured by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument during 2002–2023 and binning them based on the yaw cycle, we obtain a continuous dataset with a wide local time coverage at 50° S–80° N or 80° S–50° N. The seasonal change in temperature, caused by the forward drift in the SABER yaw cycle, is removed using the climatological temperature of the Naval Research Laboratory's Mass Spectrometer Incoherent Scatter Radar model (MSIS2.0). The corrected temperature without any waves is regarded as the mean temperature. At 50° S–50° N, the cooling trends in the mean temperature are significant in the MLT region and are in agreement with previous studies. The novel finding is that the cooling trends of ≥ l2 K per decade exhibit seasonal symmetry and reach peaks of ≥ 6 K per decade at high latitudes around the summer solstice. Moreover, there are warming trends of 1–2.5 K per decade at an altitude range of 10−2–10−3 hPa, specifically at latitudes higher than 55° N in October and December and at latitudes higher than 55° S in April and August. Over the past 22 years, the mesopause temperature (altitude) in the northern summer polar region has been ∼ 5–11 K (∼ 1 km) colder (lower) than that in the corresponding southern region. The trends in the mesopause temperature are dependent on latitudes and months, but they are negative at most latitudes and reach larger magnitudes at high latitudes. These results indicate that the temperature in the high-latitude MLT region is more sensitive to dynamic changes.

Abstract Despite recent advancement in 3D molecule conformation generation driven by diffusion models, its high computational cost in iterative diffusion/denoising process limits its application. Here, an equivariant consistency model (EC-Conf) was proposed as a fast diffusion method for low-energy conformation generation. In EC-Conf, a modified SE (3)-equivariant transformer model was directly used to encode the Cartesian molecular conformations and a highly efficient consistency diffusion process was carried out to generate molecular conformations. It was demonstrated that, with only one sampling step, it can already achieve comparable quality to other diffusion-based models running with thousands denoising steps. Its performance can be further improved with a few more sampling iterations. The performance of EC-Conf is evaluated on both GEOM-QM9 and GEOM-Drugs sets. Our results demonstrate that the efficiency of EC-Conf for learning the distribution of low energy molecular conformation is at least two magnitudes higher than current SOTA diffusion models and could potentially become a useful tool for conformation generation and sampling. Scientific Contributions In this work, we proposed an equivariant consistency model that significantly improves the efficiency of conformation generation in diffusion-based models while maintaining high structural quality. This method serves as a general framework and can be further extended to more complex structure generation and prediction tasks, including those involving proteins, in future steps.

Ion mobility spectrometry (IMS) is a trace detection technique operating at atmospheric pressure. It is widely utilized in various fields, such as explosives and drug detection, chemical warfare agent detection, and biomedical applications, due to its fast response time and high sensitivity. The various of substances can be identified through analyzing the discrepancies in the drift time of charged particles in an electric field. Depending on the polarity of the charged particles, it can operate under either positive or negative ion mode. Currently, the majority of IMS operate in only one detection mode. For example, explosives detection operates under negative ion mode, while drug detection operates under positive ion mode. However, single detection mode system is prone to miss detections because some substances may differentially respond to positive and negative detection modes. Simultaneous detection under both positive and negative ion modes can further enhance detection accuracy. In this study, a dual-drift tube ion mobility spectrometry capable of simultaneously detecting positive and negative ions was constructed using corona discharge ionization source technology and a compact dual ion-gated pulse control circuit. The instrument parameters of IMS were optimized, while simultaneously determined hexogen, methamphetamine and the metabolite of trinitrotoluene (TNT)，2,4-diamino-6-nitrotoluene (2,4-DANT). The optimal experimental conditions were selected as follows: a drift gas flow rate of 600 mL/min, a carrier gas flow rate of 500 mL/min, a drift tube temperature of 100 ℃, and a thermal desorption temperature of 200 ℃. The reduced mobility values of 1.72 cm2/V·s and 1.44 cm2/V·s are obtained through the detection of explosive hexogen (RDX) and drug methamphetamine (MA), respectively. These values agree well with the reported values, thereby proving the reliability of the instrument’s detection. Finally, the performance of the developed instrument was evaluated using 2,4-DANT, this substance that can be detected under both positive and negative ion modes. Production peaks are observed in both modes, and the normalized mobility values for 2,4-DANT are reported as approximately 1.67 cm2/V·s and 1.33 cm2/V·s under positive and negative ion modes, respectively. Through exploring the detection limits for both positive and negative ions, it was revealed that the homemade dual ion mobility spectrometer is capable of simultaneous detection of both positive and negative ions, achieves the lowest detection limits of 200 pg and 260 pg for 2,4-DANT, respectively. Importantly, these detection limits are not significantly compromised by sample division, which underscores the broad applicability and value of the instrument, highlighting its potential in various fields.