Teaching Status and Teaching Reform Ideas of Physical Chemistry Experiments for Food Quality and Safety Major

Physical chemistry experiments are an important branch of chemical experiments.In view of problems and shortcomings in physical chemistry experiment teaching of food quality and safety major in Chengdu University,the teaching methods of physical chemistry experiment course of food quality and safety major were explored and practiced,aiming to arouse students enthusiasm for experiments and cultivate their ability of independent learning,comprehensive thinking and independent problem solving.

Effects of ultrasonic-assisted extraction on bioactive compounds,volatile flavors and antioxidant activities of vine tea water extracts

Background:Ampelopsis grossedentata,vine tea,which is the tea alternative beverages in China.In vine tea processing,a large amount of broken tea is produced,which has low commercial value.Methods:This study investigates the influence of different extraction methods(room temperature water extraction,boiling water extraction,ultrasonic-assisted room temperature water extraction,and ultrasonic-assisted boiling water extraction,referred to as room temperature water extraction(RE),boiling water extraction(BE),ultrasonic assistance at room temperature water extraction(URE),and ultrasonic assistance in boiling water extraction(UBE))on the yield,dihydromyricetin(DMY)content,free amino acid composition,volatile aroma components,and antioxidant properties of vine tea extracts.Results:A notable influence of extraction temperature on the yield of vine tea extracts(P<0.05),with BE yielding the highest at 43.13±0.26%,higher than that of RE(34.29±0.81%).Ultrasound-assisted extraction significantly increased the DMY content of the extracts(P<0.05),whereas DMY content in the RE extracts was 59.94±1.70%,that of URE reached 66.14±2.78%.Analysis revealed 17 amino acids,with L-serine and aspartic acid being the most abundant in the extracts,nevertheless ultrasound-assisted extraction reduced total free amino acid content.Gas chromatography-mass spectrometry analysis demonstrated an increase in the diversity and quantity of compounds in the vine tea water extracts obtained through ultrasonic-assisted extraction.Specifically,69 and 68 volatile compounds were found in URE and UBE extracts,which were higher than the number found in RE and BE extracts.In vitro,antioxidant activity assessments revealed varying antioxidant capacities among different extraction methods,with RE exhibiting the highest DPPH scavenging rate,URE leading in ABTS•+free radical scavenging,and BE demonstrating superior ferric ion reducing antioxidant activity.Conclusion:The findings suggest that extraction methods significantly influence the chemical composition and antioxidant properties of vine tea extracts.Ultrasonic-assisted extraction proved instrumental in elevating the DMY content in vine tea extracts,thereby enriching its flavor profile while maintaining its antioxidant properties.

Focusing on the recent progress of tea polyphenol chemistry and perspectives

Myriad evidence attests to the health-promoting benefits of tea drinking.While there are multiple factors of tea influencing the effective biological properties,tea polyphenols are the most significant and valuable components.The chemical characterization and physical characteristics of tea polyphenols have been comprehensively studied over the previous years.Still the emergence of new chemistry in tea,particularly the property of scavenging reactive carbonyl species(RCS)and the newly discovered flavoalkaloid compounds,has drawn increasing attention.In this review,we summarize recent findings of a new class of compounds in tea-flavonoid alkaloids(flavoalkaloids),which exist in fresh tea leaves and can be generated during the process of post-harvesting,and also postulate the formation mechanism of flavoalkaloids between catechins and theanine-derived Strecker aldehyde.Additionally,we detail the up-to-date research results of tea polyphenols regarding their ability to trap RCS and their in vivo aminated metabolites to suppress advanced glycation ends products(AGEs).We further raise questions to be addressed in the near future,including the synthetic pathways for the generation of flavoalkaloids and AGEs in fresh tea leaves before processing and the concentrations of tea polyphenols that affect their RCS scavenging capability due to their pro-oxidant nature.More intensive research is warranted to elucidate the mechanisms of action underlying the biological activity of flavoalkaloids and the pharmacological application of tea polyphenols in scavenging RCS and impeding detrimental AGEs.

基于文化自信的中外合作办学学科基础课“General Chemistry”课程思政建设探索与实践

“General Chemistry”是面向中外合作办学工科专业学生开设的一门学科基础课。为了提升教学质量,课程引入国外经典教材,在教学过程中面临外来文化的冲击和文化自信缺失的风险。因此,必须通过“General Chemistry”课程思政教学提升学生对自身文化的深度认同。本文中,“General Chemistry”课程思政建设坚持文化自信理念,积极挖掘中国思政元素,将中外思政元素合理融入到教学的每一个环节,不断助推课程思政教学内涵式发展,打造课程思政高效课堂,取得了较好的育人成效。

TEAD1/TEAD4基因多态性与非贲门胃癌变关系的研究

目的探讨TEA转录因子1(TEAD1)基因单核苷酸多态性(SNP)rs2304733、TEA转录因子4(TEAD4)SNPrs7135838和rs1990330与非贲门胃癌变发病风险的关系。方法采用酶联免疫吸附测定法(ELISA)检测正常对照组血清样本中抗幽门螺杆菌(Hp)的特异性抗体,根据抗体滴度将470例正常对照组分为Hp感染阴性组(n=223)和阳性组(n=247)。在450例非贲门胃癌病例组和470例对照组中,采用聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)技术对各SNP位点进行基因分型,采用非条件性Logistic回归评估各SNP位点与非贲门胃癌变发病风险的关系。结果TEAD1、TEAD4各SNP位点均与Hp感染没有关联;TEAD1 rs2304733与非贲门胃癌的发病风险相关,与携带TT基因型者相比,携带CT基因型及CC基因型者均增加了非贲门胃癌的发病风险(CTvsTT:OR=2.321,95%CI:1.690~3.188;CCvsTT:OR=5.140,95%CI:1.080~24.463);TEAD4 rs1990330与非贲门胃癌发病风险相关,与携带GG基因型者相比,携带GT基因型者增加了非贲门胃癌的发病风险(OR=2.405,95%CI:1.480~3.908);TEAD4 rs7135838与非贲门胃癌的发病风险无关联;TEAD1rs2304733、TEAD4 rs7135838以及rs1990330对非贲门胃癌发病风险存在交互作用(P<0.05)。结论在包头地区汉族人群中,TEAD1 rs2304733、TEAD4 rs1990330在Hp感染中不起主要作用,在非贲门胃癌发病风险中可能起一定作用;TEAD4 rs7135838在Hp感染以及非贲门胃癌发病风险中可能均不起主要作用;TEAD1 rs2304733、TEAD4 rs1990330对非贲门胃癌发病风险的协同效应最强,为最佳交互模型。

CircFoxo3调节miR-130a-5p/TEAD1轴对心力衰竭大鼠心肌细胞凋亡影响的实验研究

目的探讨环状RNA叉头框蛋白O3(CircFoxo3)调节miR-130a-5p/TEA域转录因子1(TEAD1)轴对心力衰竭(HF)大鼠心肌细胞凋亡的影响。方法将SD大鼠分为对照组、HF组、si-NC组、si-CircFoxo3组、agomir NC组、miR-130a-5p agomir组、si-CircFoxo3+antagomir NC组、si-CircFoxo3+miR-130a-5p antagomir组,每组18只。除对照组外,其他组大鼠均通过腹腔注射盐酸阿霉素的方法构建HF大鼠模型。建模成功后进行药物处理,每3 d给药一次,持续3周。应用反转录实时荧光定量聚合酶链式反应(qRT-PCR)法检测心肌组织中CircFoxo3、miR-130a-5p表达水平。应用彩色多普勒超声仪检测大鼠左室收缩末期内径(LVESD)、左室舒张末期内径(LVEDD)、左室射血分数(LVEF)水平。采用酶联免疫吸附试验(ELISA)法检测大鼠血清人基质裂解素2(ST_(2))、N端脑钠肽前体(NT-pro BNP)水平。应用HE染色、Masson染色检测大鼠心肌组织病理变化和心肌纤维化情况。通过TUNEL染色检测心肌细胞凋亡水平。应用Western blot法检测大鼠心肌组织TEA域转录因子1(TEAD1)、B淋巴细胞瘤-2(Bcl-2)、Bcl-2相关X蛋白(Bax)、裂解的天冬氨酸特异性半胱氨酸蛋白酶-3(cleaved caspase-3)蛋白表达水平。通过双荧光素酶报告基因实验验证CircFoxo3与miR-130a-5p、miR-130a-5p与TEAD1的关系。结果与对照组比较,HF组大鼠心肌组织病理损伤、心肌纤维化严重,LVESD、LVEDD水平上升,心肌组织CircFoxo3及TEAD1、Bax、cleaved caspase-3蛋白表达水平升高,血清ST_(2)、NT-pro BNP水平升高,心肌细胞凋亡率升高,LVEF、miR-130a-5p和Bcl-2蛋白水平降低,差异有统计学意义(P<0.05)。与HF组、si-NC组比较,si-CircFoxo3组大鼠心肌组织病理损伤减轻,LVESD、LVEDD水平降低,心肌组织CircFoxo3及TEAD1、Bax、cleaved caspase-3蛋白表达水平降低,血清ST_(2)、NT-pro BNP水平降低,心肌细胞凋亡率降低,LVEF、miR-130a-5p及Bcl-2蛋白水平升高,差异有统计学意义(P<0.05)。与HF组、agomir NC组比较,miR-130a-5p agomir组大鼠心肌组织病理损伤、心肌纤维化有所改善,LVESD、LVEDD水平降低,心肌组织TEAD1、Bax、cleaved caspase-3蛋白表达水平降低,血清ST_(2)、NT-pro BNP水平降低,心肌细胞凋亡率降低,LVEF、miR-130a-5p及Bcl-2蛋白水平升高,差异有统计学意义(P<0.05)。与si-CircFoxo3组、si-CircFoxo3+antagomir NC组比较,si-CircFoxo3+miR-130a-5p antagomir组大鼠心肌组织病理损伤、心肌纤维化加剧,LVESD、LVEDD水平升高,心肌组织TEAD1、Bax、cleaved caspase-3蛋白表达水平升高,血清ST_(2)、NT-pro BNP水平升高,心肌细胞凋亡率升高,LVEF、miR-130a-5p、Bcl-2蛋白水平降低,差异有统计学意义(P<0.05)。CircFoxo3与miR-130a-5p、miR-130a-5p与TEAD1存在靶向关系。结论沉默CircFoxo3可能通过海绵化上调miR-130a-5p来抑制TEAD1表达,进而抑制HF大鼠心肌细胞凋亡。

THE PROCESSES OF ATMOSPHERIC IMPURITIES TRANSPORTATION OVER THE QINGHAI—TIBET PLATEAU AS REVEALED BY SEASONAL RECORDS OF SNOW CHEMISTRY

Chemical records were recovered from snow pits samples collected over the two transects (south\|north transect and southeast\|northwest transect) of the Qinghai—Tibetan plateau. It shows that the mean concentration of the major ions over the south regions of Mt. Tanggula is lower than that of the north regions. The flux of major ions over north plateau is over 3 times higher than the south. The cloudy atmosphere of the north plateau is mainly contributed to the local input of dust, while in the south plateau, sea salt ions transported by Indian monsoon is considerable. The continental dust transportation from the north and the marine aerosol transportation from the south reach an approximately equilibrium around Mt. Tanggula regions. Stable oxygen isotopic ratios ( δ 18 O) in precipitation from the south\|north transect shows that, over the north plateau, δ 18 O is positively correlated with temperature, while over south of the plateau the correlation becomes weak and δ 18 O is more correlated with the amount of precipitation.

Teaching Effectiveness of Integrating Task-based Approach into Inorganic and Analytical Chemistry Course

From the perspective of students,the effectiveness of task-based approach in In-organic and Analytical Chemistry course were summarized.The strength and weak points of TBA were analyzed,and the specific suggestions for obtaining better effect were put forward.The result showed a satisfactory achievement and unexpected result in showing the effectiveness of this teaching model.Not only could this TBA enhance student's overall knowledge of discipline but also cultivate students' multi-dimensional competence:competence in searching literatures, communication and management,autonomous,co-operative and reflective learning,and competence in analyzing and problem-solving,as well as improving their language expression ability,and skills in using multi-media and internet technology into their academic course learning and research.The implication of this research on the classroom teaching practice will shed light on the future teaching reform of other courses in China.

The effects of science,technology,society,environment(STSE)interactions on teaching chemistry

This study aimed to investigate the effects of making Science, Technology, Society and En-vironment relations on students’ comprehen-sion of chemistry topics through teaching che-mistry using STSE approach at secondary level. The study made use of the research model where pre and post tests were administered to control and treatment groups. The Chemistry Achievement Test (CAT) was used in the study. The sampling consisted of Grade 9 students studying at Anatolian High School and Voca-tional High School. Since the sampling had not been equated, in order to determine students’ logical and spatial thinking skills, they were administered Logical Thinking Skill Test and Mental Rotation test as pretests. Students were chosen randomly to take part in two control and two treatment groups. This experimental study was applied to the treatment group in teaching of “Separation of Mixtures” topic in Grade 9 Chemistry course during a four-week period. Students in the control group were taught through the traditional teaching methods. The data obtained were analyzed through the SPSS Software. As a result of the study, statistically significant increases were observed in the achievement levels of treatment group which received instruction using STSE relations. The change observed in the achievement levels of the control group was not statistically signifi-cant. The difference between the achievement levels of control and treatment groups in the posttests were favoring the treatment groups.

Mineral Chemistry of Wehrlite Xenoliths Hosted in Basalts from the SW of Hossere Dammougalre(Adamawa Plateau,Cameroon):Thermobarometric Implications

Wehrlite samples (size: ~4 cm) hosted in basaltic lavas from the SW of Hosséré Dammougalré are located in the western Adamawa Plateau. Porphyritic and allotriomorphic texture characterize respectively host Basalt and wehrlite xenoliths. The phenocrysts of olivine (Fo68&minus;74), and Ti-magnetite are scattered in host basalt. Wehrlite xenoliths (~4 cm size) contain Cr-rich clinopyroxene (diopise-augite), olivine (Fo76&minus;88) and chromiferous spinel. Equilibrium temperatures calculated from Fe/Mg exchange reaction for olivine/spinel vary between 944&#176;C and 1102&#176;C. The wehrlite olivine crystals with low Fo (<90) indicate a re-equilibration of Fe-Mg in the host basalt at low temperatures. All the analyzed wehrlite clinopyroxenes have crystallized at high pressures as evidenced by the Alvi and Aliv contents. The studied spinel-bearing wehrlite xenoliths represent probably the residual portions of the upper mantle, which are an important source of information about lithospheric composition and thermal evolution beneath the Adamawa Plateau.

Achieving asymmetric redox chemistry for oxygen evolution reaction through strong metal-support interactions

Water electrolysis poses a significant challenge for balancing catalytic activity and stability of oxygen evolution reaction(OER)electrocatalysts.In this study,we address this challenge by constructing asymmetric redox chemistry through elaborate surface OO–Ru–OH and bulk Ru–O–Ni/Fe coordination moieties within single-atom Ru-decorated defective NiFe LDH nanosheets(Ru@d-NiFe LDH)in conjunction with strong metal-support interactions(SMSI).Rigorous spectroscopic characterization and theoretical calculations indicate that single-atom Ru can delocalize the O 2p electrons on the surface and optimize d-electron configurations of metal atoms in bulk through SMSI.The^(18)O isotope labeling experiment based on operando differential electrochemical mass spectrometry(DEMS),chemical probe experiments,and theoretical calculations confirm the encouraged surface lattice oxygen,stabilized bulk lattice oxygen,and enhanced adsorption of oxygen-containing intermediates for bulk metals in Ru@d-NiFe LDH,leading to asymmetric redox chemistry for OER.The Ru@d-NiFe LDH electrocatalyst exhibits exceptional performance with an overpotential of 230 mV to achieve 10 mA cm^(−2)and maintains high robustness under industrial current density.This approach for achieving asymmetric redox chemistry through SMSI presents a new avenue for developing high-performance electrocatalysts and instills confidence in its industrial applicability.

Characterization of mulberry leaf instant tea and evaluation of its hypolipidemia effect via regulation of intestinal microbiota

The purpose of this study was to characterize mulberry leaf instant tea(MLIT)powder prepared from the'Longsang No.1'(Morus abla L.cv.Longsang 1)mulberry leaves in Heilongjiang Province(China)and assess its obesity-preventing/relieving effects.A total of 174 compounds including quercetin,chlorogenic acid,1-deoxyecomycin(1-DNJ)related to antihyperlipidemia effects were identified from the MLIT powder.MLIT treatment reversed the Lee's index,fat coefficient,and serum biochemical parameters in both the obesity relieving and obesity preventing mice fed with high-fat diet.In the obesity relieving experiment,the relative abundance of Desulfovibrio in mouse feces decreased after both 0.5%and 1%MLIT treatments.In obesity preventing experiments,mouse with different amount of MLIT treatments showed increased relative abundance of Akkermansia,Bifidobacterium and Lactobacillus,while Deferribacteres,Desulfobacterota decreased.The beneficial bacteria in the intestinal tract of mice treated with MLIT increased.This study proved that MLIT had antihyperlipidemia potential via modulating intestinal microbiota in mice.

Antibacterial mechanism of kojic acid and tea polyphenols against Escherichia coli O157:H7 through transcriptomic analysis

Escherichia coli O157:H7 is one of the major foodborne pathogenic bacterial that cause infectious diseases in humans.The previous found that a combination of kojic acid and tea polyphenols exhibited better activity against E.coli O157:H7 than using either alone.This study aimed to explore responses underlying the antibacterial mechanisms of kojic acid and tea polyphenols from the gene level.The functional enrichment analysis by comparing kojic acid and tea polyphenols individually or synergistically against E.coli O157:H7 found that acid resistance systems in kojic acid were activated,and the cell membrane and genomic DNA were destructed in the cells,resulting in“oxygen starvation”.The oxidative stress response triggered by tea polyphenols inhibited both sulfur uptake and the synthesis of ATP,which affected the bacteria's life metabolic process.Interestingly,we found that kojic acid combined with tea polyphenols hindered the uptake of iron that played an essential role in the synthesis of DNA,respiration,tricarboxylic acid cycle.The results suggested that the iron uptake pathways may represent a novel approach for kojic acid and tea polyphenols synergistically against E.coli O157:H7 and provided a theoretical basis for bacterial pathogen control in the food industry.

Teaching Polymer Chemistry: Revisiting the Syllabus

As anyone who has taught polymer chemistry to undergraduate students might already appreciate, we are faced with inherent difficulties in clearly communicating the subject matter due its interdisciplinary character. This paper is thus aimed at proposing a new educational plan to teach this fundamental course in order to overcome some inherent obstacles. It is especially devoted to professors in charge of teaching a first course in polymer chemistry. We intend to emphasize polymerization by beginning with the simplest chemical pathway, namely the living anionic polymerization. In addition, some pedagogical difficulties are outlined all along this paper. This novel and distinct way to teach polymer chemistry makes the students with a background in organic chemistry more equipped to face difficulties arising from the introduction of new concepts.

Proximity of Problem-Based Learning(ABP)Methodology to Experimental Teaching in Organic Chemistry.IMINE Synthesis

Different imines were prepared.The reaction was carried out using different conditions,with aromatic aldehydes,aniline and with different energy sources.Yield,purity and experimental fusion point were calculated in each case,and they were compared to the ones found in literature.The importance of structural effects of aldehyde reacting with aniline was established as well as reaction conditions.The efficacy of the reaction can not be predicted,since each aldehyde has a different structure and therefore reacts differently.The main objective of this project is academic.A methodology to carry out a structured research(it is one of the levels of problem-based learning(ABP)),was implemented.Students work in pairs using Combinatorial Chemistry,and each pair does a different exercise on the same theoretical objective.Results from every team are discussed in a seminary where conclusions regarding which was the most efficient reaction are reached.

Designing ultrastable P2/O3-type layered oxides for sodium ion batteries by regulating Na distribution and oxygen redox chemistry

P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phases remains a necessity.Herein,we design a P2/O3-type Na_(0.76)Ni_(0.31)Zn_(0.07)Mn_(0.50)Ti_(0.12)0_(2)(NNZMT)with high chemical/electrochemical stability by enhancing the coupling between the two phases.For the first time,a unique Na*extraction is observed from a Na-rich O3 phase by a Na-poor P2 phase and systematically investigated.This process is facilitated by Zn^(2+)/Ti^(4+)dual doping and calcination condition regulation,allowing a higher Na*content in the P2 phase with larger Na^(+)transport channels and enhancing Na transport kinetics.Because of reduced Na^(+)in the O3 phase,which increases the difficulty of H^(+)/Na^(+) exchange,the hydrostability of the O3 phase in NNZMT is considerably improved.Furthermore,Zn^(2+)/Ti^(4+)presence in NNZMT synergistically regulates oxygen redox chemistry,which effectively suppresses O_(2)/CO_(2) gas release and electrolyte decomposition,and completely inhibits phase transitions above 4.0 V.As a result,NNZMT achieves a high discharge capacity of 144.8 mA h g^(-1) with a median voltage of 3.42 V at 20 mA g^(-1) and exhibits excellent cycling performance with a capacity retention of 77.3% for 1000 cycles at 2000 mA g^(-1).This study provides an effective strategy and new insights into the design of high-performance layered-oxide cathode materials with enhanced structure/interface stability forSIBs.

Remote Teaching of Experimental Chemistry in Developing Countries

During the ongoing 2020 CoVid-19 crisis,the use of remote meeting technologies such as Zoom™,Microsoft Teams™and Google Meetings™has been paramount to theoretical teaching in a safe socially distanced environment.However,several problems arise when there is a need for an experimental approach.This paper looks at one of the possible solutions,including how to best separate the students,how to minimize close interactions and how a mixed environment of remote/presential teaching is required,minimizing the amount of extra materials,resources and protection equipment required,such that developing countries can quickly adopt this method,without the purchase of any external equipment.

Practical Exploration of Inquiry Teaching Method inChemistry Teaching of Higher Vocational Colleges

Since the concept of quality education is put forward,all colleges and universities has done a lot of exploration on teachingmethods,as it is on higher vocational chemistry teaching, inquiry teaching method is one of the many methods of chemistry teaching in highervocational colleges,its characteristic is to set up the scene and the question in the teaching,induce students to think,determine the way ofinquiry finally.After this it also need to experience multiple links,such as hypotheses,tests,results discussion,and so on,through flexible teachingmethods,arouse students ＇ interest in chemistry and study enthusiasm to the maximum extent,promote students to learn actively, cultivate the corequality of students,promote the comprehensive development of students ＇ theory and practice,train more comprehensive talents with high qualityfor the society.

Teaching of Organic Chemistry of Cultivating Applied Pharmaceutical Talents

In order to effectively cultivate applied pharmaceutical talents,aiming at the current teaching situation of organic chemistry,the basic course of pharmaceutical specialty,including the problems of curriculum setting,experimental teaching,and the integration of classroom and professional knowledge,it is proposed to overcome the problem of curriculum setting by combining"online+offline"in teaching.It should overcome the problems in experimental teaching with the help of virtual simulation platform.By cultivating students organic chemistry thinking and paying attention to the integration of subject and professional knowledge,students recognition of organic chemistry course can be improved,and the quality of training can be improved.

Micro-polymer Chemistry Experiment Teaching Research

For nearly thirty years, there has been made great progress in micro-polymer chemistry experiment teaching which has these characteristics that using less reagents, less pollution and more portable in comparison with the conventional experiment. In China, Zhou Ninghuai and others began to go on micro-scale experiment research firstly and Professor Li Qingshan who brought this innovation to polymer organic synthesis experiment has done a lot of works in micro-polymer chemistry experiment teaching. To carry out the study of micro-polymer chemistry experiments not only accords with teaching methods and reform, but also conforms to the trend of the times of green chemistry. So the research and application of micro-polymer chemistry experiment have broad prospects.