WorldWideScience

Sample records for activation chemistry

  1. Activity cliff networks for medicinal chemistry.

    Science.gov (United States)

    Stumpfe, Dagmar; Bajorath, Jürgen

    2014-08-01

    Network representations are widely used in bioinformatics but have only been little explored in chemistry. Thus far, only a few attempts have been made to generate and analyze compound networks. Among these are the first activity cliff networks. In medicinal chemistry, activity cliffs are focal points of structure-activity relationships (SAR) analysis. Activity cliffs have generally been defined as pairs of structurally similar or analogous active compounds that have a large difference in potency against their target. However, most activity cliffs are not formed in isolation but in a coordinated manner involving multiple highly and weakly potent compounds. Recently, a comprehensive activity cliff network has been generated for current public domain bioactive compounds, hence providing a first global view of activity cliff formation. The design of activity cliff networks is discussed herein. From the global activity cliff network, local networks can be extracted for individual compound activity classes that provide graphical access to high-level SAR information for compound optimization efforts.

  2. Using Art-Based Chemistry Activities to Improve Students' Conceptual Understanding in Chemistry

    Science.gov (United States)

    Danipog, Dennis L.; Ferido, Marlene B.

    2011-01-01

    This study aimed to determine the effects of art-based chemistry activities (ABCA) on high school students' conceptual understanding in chemistry. The study used the pretest-posttest control group design. A total of 64 third-year high school students from two different chemistry classes participated in the study. One class was exposed to art-based…

  3. Using Art-Based Chemistry Activities to Improve Students' Conceptual Understanding in Chemistry

    Science.gov (United States)

    Danipog, Dennis L.; Ferido, Marlene B.

    2011-01-01

    This study aimed to determine the effects of art-based chemistry activities (ABCA) on high school students' conceptual understanding in chemistry. The study used the pretest-posttest control group design. A total of 64 third-year high school students from two different chemistry classes participated in the study. One class was exposed to art-based…

  4. Spilanthol: occurrence, extraction, chemistry and biological activities

    Directory of Open Access Journals (Sweden)

    Alan F. Barbosa

    2016-02-01

    Full Text Available Abstract Spilanthol (C14H23NO, 221.339 g/mol is a bioactive compound that is found in many different plants that are used as traditional remedies throughout the world. It is present in Heliopsis longipes and several species in the genus Acmella, including A. oleracea L., also known as paracress and jambu. Its leaves and flowers have sensory properties (pungency, tingling, numbing, mouth-watering that make it a popular spice and ingredient in several Brazilian dishes. Spilanthol can exert a variety of biological and pharmacological effects including analgesic, neuroprotective, antioxidant, antimutagenic, anti-cancer, anti-inflammatory, antimicrobial, antilarvicidal and insecticidal activities. So, the aim of this review is to present a literature review on the spilanthol that describes its occurrence, chemistry, extraction and biological activities.

  5. Using Computational Chemistry Activities to Promote Learning and Retention in a Secondary School General Chemistry Setting

    Science.gov (United States)

    Ochterski, Joseph W.

    2014-01-01

    This article describes the results of using state-of-the-art, research-quality software as a learning tool in a general chemistry secondary school classroom setting. I present three activities designed to introduce fundamental chemical concepts regarding molecular shape and atomic orbitals to students with little background in chemistry, such as…

  6. Writing Chemistry Jingles as an Introductory Activity in a High School Chemistry Class

    Science.gov (United States)

    Heid, Peter F.

    2011-01-01

    Starting the school year in an introductory high school chemistry class can be a challenge. The topic and approach is new to the students; many of the early chapters in the texts can be a bit tedious; and for many students the activities are uninspiring. My goal in the first few weeks of school is to hook the students on chemistry by getting them…

  7. Using Computational Chemistry Activities to Promote Learning and Retention in a Secondary School General Chemistry Setting

    Science.gov (United States)

    Ochterski, Joseph W.

    2014-01-01

    This article describes the results of using state-of-the-art, research-quality software as a learning tool in a general chemistry secondary school classroom setting. I present three activities designed to introduce fundamental chemical concepts regarding molecular shape and atomic orbitals to students with little background in chemistry, such as…

  8. Active Learning Applications in the History of Chemistry: Pre-Service Chemistry Teachers' Level of Knowledge and Views

    Science.gov (United States)

    Sendur, Gülten; Polat, Merve; Toku, Abdullah; Kazanci, Coskun

    2014-01-01

    This study aims to investigate the effects of a History and Philosophy of Chemistry-I course based on active learning applications on the level of knowledge of pre-service chemistry teachers about the history of chemistry. The views of pre-service chemistry teachers about these activities were also investigated. The study was carried out with 38…

  9. The rise of environmental analytical chemistry as an interdisciplinary activity.

    Science.gov (United States)

    Brown, Richard

    2009-07-01

    Modern scientific endeavour is increasingly delivered within an interdisciplinary framework. Analytical environmental chemistry is a long-standing example of an interdisciplinary approach to scientific research where value is added by the close cooperation of different disciplines. This editorial piece discusses the rise of environmental analytical chemistry as an interdisciplinary activity and outlines the scope of the Analytical Chemistry and the Environmental Chemistry domains of TheScientificWorldJOURNAL (TSWJ), and the appropriateness of TSWJ's domain format in covering interdisciplinary research. All contributions of new data, methods, case studies, and instrumentation, or new interpretations and developments of existing data, case studies, methods, and instrumentation, relating to analytical and/or environmental chemistry, to the Analytical and Environmental Chemistry domains, are welcome and will be considered equally.

  10. ict in teaching and learning chemistry activities on the ipad

    African Journals Online (AJOL)

    IICBA01

    technology such as iPads and a variety of interfaces and sensors (probes) bundled with computer- based activities for chemistry and general science. Participants .... 1445-1545 Digital Laboratory Denis Zhilin ... Science+Business Media. 3.

  11. Medicinal chemistry of drugs with active metabolites following conjugation.

    Science.gov (United States)

    Kalász, Huba; Petroianu, Georg; Hosztafi, Sándor; Darvas, Ferenc; Csermely, Tamás; Adeghate, Ernest; Siddiq, Afshan; Tekes, Kornélia

    2013-10-01

    Authorities of Drug Administration in the United States of America approved about 5000 drugs for use in the therapy or management of several diseases. About two hundred of these drugs have active metabolites and the knowledge of their medicinal chemistry is important both in medical practice and pharmaceutical research. This review gives a detailed description of the medicinal chemistry of drugs with active metabolites generated after conjugation. This review focused on glucuronide-, acetyl-, sulphate- and phosphate-conjugation of drugs, converting the drug into an active metabolite. This conversion essentially changed the lipophilicity of the drug.

  12. Empowering Girls with Chemistry, Exercise and Physical Activity

    Science.gov (United States)

    Clapham, Emily D.; Ciccomascolo, Lori E.; Clapham, Andrew J.

    2015-01-01

    Research suggests that a girl's career interests in the areas of science, technology, engineering and mathematics (STEM) declines between grades 6 and 8. Similarly, in middle school, there is a decrease in physical activity among girls. Researchers at the University of Rhode Island (URI) conducted a chemistry-based science camp that took place…

  13. Empowering Girls with Chemistry, Exercise and Physical Activity

    Science.gov (United States)

    Clapham, Emily D.; Ciccomascolo, Lori E.; Clapham, Andrew J.

    2015-01-01

    Research suggests that a girl's career interests in the areas of science, technology, engineering and mathematics (STEM) declines between grades 6 and 8. Similarly, in middle school, there is a decrease in physical activity among girls. Researchers at the University of Rhode Island (URI) conducted a chemistry-based science camp that took place…

  14. Synthetic Methods, Chemistry, and the Anticonvulsant Activity of Thiadiazoles

    Directory of Open Access Journals (Sweden)

    Bhawna Sharma

    2013-01-01

    Full Text Available The chemistry of heterocyclic compounds has been an interesting field of study for a long time. Heterocyclic nucleus 1,3,4-thiadiazole constitutes an important class of compounds for new drug development. The synthesis of novel thiadiazole derivatives and investigation of their chemical and biological behavior have gained more importance in recent decades. The search for antiepileptic compounds with more selective activity and lower toxicity continues to be an active area of intensive investigation in medicinal chemistry. During the recent years, there has been intense investigation of different classes of thiadiazole compounds, many of which possess extensive pharmacological activities, namely, antimicrobial activity, anticonvulsant, antifungal antidiabetic, anti-inflammatory, antioxidant, and antituberculosis activities, and so forth. The resistance towards available drugs is rapidly becoming a major worldwide problem. The need to design new compounds to deal with this resistance has become one of the most important areas of research today. Thiadiazole is a versatile moiety that exhibits a wide variety of biological activities. Thiadiazole moiety acts as “hydrogen binding domain” and “two-electron donor system.” It also acts as a constrained pharmacophore. On the basis of the reported literature, we study here thiadiazole compounds and their synthetic methods chemistry and anticonvulsant activity.

  15. Rhodiola plants: Chemistry and biological activity

    Directory of Open Access Journals (Sweden)

    Hsiu-Mei Chiang

    2015-09-01

    Full Text Available Rhodiola is a genus of medicinal plants that originated in Asia and Europe and are used traditionally as adaptogens, antidepressants, and anti-inflammatory remedies. Rhodiola plants are rich in polyphenols, and salidroside and tyrosol are the primary bioactive marker compounds in the standardized extracts of Rhodiola rosea. This review article summarizes the bioactivities, including adaptogenic, antifatigue, antidepressant, antioxidant, anti-inflammatory, antinoception, and anticancer activities, and the modulation of immune function of Rhodiola plants and its two constituents, as well as their potential to prevent cardiovascular, neuronal, liver, and skin disorders.

  16. Rhodiola plants: Chemistry and biological activity.

    Science.gov (United States)

    Chiang, Hsiu-Mei; Chen, Hsin-Chun; Wu, Chin-Sheng; Wu, Po-Yuan; Wen, Kuo-Ching

    2015-09-01

    Rhodiola is a genus of medicinal plants that originated in Asia and Europe and are used traditionally as adaptogens, antidepressants, and anti-inflammatory remedies. Rhodiola plants are rich in polyphenols, and salidroside and tyrosol are the primary bioactive marker compounds in the standardized extracts of Rhodiola rosea. This review article summarizes the bioactivities, including adaptogenic, antifatigue, antidepressant, antioxidant, anti-inflammatory, antinoception, and anticancer activities, and the modulation of immune function of Rhodiola plants and its two constituents, as well as their potential to prevent cardiovascular, neuronal, liver, and skin disorders. Copyright © 2015. Published by Elsevier B.V.

  17. Indoor Chemistry: Materials, Ventilation Systems, and Occupant Activities

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, G.C.; Corsi, R.L.; Destaillats, H.; Nazaroff, W.W.; Wells, J.R.

    2006-05-01

    Chemical processes taking place in indoor environments can significantly alter the nature and concentrations of pollutants. Exposure to secondary contaminants generated in these reactions needs to be evaluated in association with many aspects of buildings to minimize their impact on occupant health and well-being. Focusing on indoor ozone chemistry, we describe alternatives for improving indoor air quality by controlling chemical changes related to building materials, ventilation systems, and occupant activities.

  18. The Chemistry and Biological Activities of Mimosine: A Review.

    Science.gov (United States)

    Nguyen, Binh Cao Quan; Tawata, Shinkichi

    2016-08-01

    Mimosine [β-[N-(3-hydroxy-4-oxypyridyl)]-α-aminopropionic acid] is a non-protein amino acid found in the members of Mimosoideae family. There are a considerable number of reports available on the chemistry, methods for estimation, biosynthesis, regulation, and degradation of this secondary metabolite. On the other hand, over the past years of active research, mimosine has been found to have various biological activities such as anti-cancer, antiinflammation, anti-fibrosis, anti-influenza, anti-virus, herbicidal and insecticidal activities, and others. Mimosine is a leading compound of interest for use in the development of RAC/CDC42-activated kinase 1 (PAK1)-specific inhibitors for the treatment of various diseases/disorders, because PAK1 is not essential for the growth of normal cells. Interestingly, the new roles of mimosine in malignant glioma treatment, regenerative dentistry, and phytoremediation are being emerged. These identified properties indicate an exciting future for this amino acid. The present review is focused on the chemistry and recognized biological activities of mimosine in an attempt to draw a link between these two characteristics. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Using active learning methodologies in physical chemistry in CLIL contexts

    Directory of Open Access Journals (Sweden)

    David Recatalá

    2016-03-01

    Full Text Available One of the main objectives of the European Higher Education Area (EHEA is to promote a change toward a student-centred education model. This fact has led to the implementation of novel methodologies based on active learning, aimed at engaging students’ interest. This implementation has been usually accompanied by significant changes in both the teaching and learning processes in European universities. Furthermore, teaching a subject through the medium of a foreign language has also been gaining attention over the past few years. More specifically, this approach commonly known as Content and Language Integrated Learning (CLIL has been employed for the simultaneous learning of content and English in a number of European countries. In this contribution we report on the active learning methods implemented in a Physical Chemistry course, as well as the efforts devoted to Content and English Language Integration in this subject. This research analyses a series of factors that can contribute to the global learning and teaching experience when both active learning and CLIL are implemented in the Physical Chemistry classroom. Some examples of them include changes in attitudes towards the subject, engagement and motivation during the course, perception of English learning, and in general, students’ satisfaction with the learning process.

  20. Combustion chemistry - activities in the CHEK research programme

    Energy Technology Data Exchange (ETDEWEB)

    Dam-Johansen, K.; Johnsson, J.E.; Glarborg, P.; Frandsen, F.; Jensen, A.; Oestberg, M. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Chemical Engineering

    1997-10-01

    The combustion chemistry in the oxidation of fossil fuels and biofuels determines together with mixing and heat transfer the required size of a furnace, the emission of gaseous pollutants, and the formation of ash and deposits on surfaces. This presentation describes technologies for solid fuels combustion and gives a summary of the fuels, the pollutant chemistry and the inorganic chemistry in combustion processes. Emphasis is put on the work carried out in the CHEC (Combustion and Harmful Emission Control) Research Programme. (orig.)

  1. Ethnobotany, chemistry, and biological activities of the genus Tithonia (Asteraceae).

    Science.gov (United States)

    Chagas-Paula, Daniela A; Oliveira, Rejane B; Rocha, Bruno A; Da Costa, Fernando B

    2012-02-01

    The genus Tithonia is an important source of diverse natural products, particularly sesquiterpene lactones, diterpenes, and flavonoids. The collected information in this review attempts to summarize the recent developments in the ethnobotany, biological activities, and secondary metabolite chemistry of this genus. More than 100 structures of natural products from Tithonia are reported in this review. The species that has been most investigated in this genus is T. diversifolia, from which ca. 150 compounds were isolated. Biological studies are described to evaluate the anti-inflammatory, analgesic, antimalarial, antiviral, antidiabetic, antidiarrhoeal, antimicrobial, antispasmodic, vasorelaxant, cancer-chemopreventive, cytotoxic, toxicological, bioinsecticide, and repellent activities. A few of these studies have been carried out with isolated compounds from Tithonia species, but the majority has been conducted with different extracts. The relationship between the biological activity and the toxicity of compounds isolated from the plants of this genus as well as T. diversifolia extracts still remains unclear, and mechanisms of action remain to be determined. Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich.

  2. The Effect of Chemistry Laboratory Activities on Students' Chemistry Perception and Laboratory Anxiety Levels

    Science.gov (United States)

    Aydogdu, Cemil

    2017-01-01

    Chemistry lesson should be supported with experiments to understand the lecture effectively. For safety laboratory environment and to prevent laboratory accidents; chemical substances' properties, working principles for chemical substances' usage should be learnt. Aim of the present study was to analyze the effect of experiments which depend on…

  3. Evaluation of Potential Impacts of Microbial Activity on Drift Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Y. Wang

    2004-11-18

    ''Evaluation of Potential Impacts of Microbial Activity on Drift Chemistry'' focuses on the potential for microbial communities that could be active in repository emplacement drifts to influence the in-drift bulk chemical environment. This report feeds analyses to support the inclusion or exclusion of features, events, and processes (FEPs) in the total system performance assessment (TSPA) for the license application (LA), but this work is not expected to generate direct feeds to the TSPA-LA. The purpose was specified by, and the evaluation was performed and is documented in accordance with, ''Technical Work Plan For: Near-Field Environment and Transport In-Drift Geochemistry Analyses'' (BSC 2004 [DIRS 172402], Section 2.1). This report addresses all of the FEPs assigned by the technical work plan (TWP), including the development of exclusion arguments for FEPs that are not carried forward to the TSPA-LA. Except for an editorial correction noted in Section 6.2, there were no other deviations from the TWP. This report documents the completion of all assigned tasks, as follows (BSC 2004 DIRS 172402, Section 1.2.1): (1) Perform analyses to evaluate the potential for microbial activity in the waste emplacement drift under the constraints of anticipated physical and chemical conditions. (2) Evaluate uncertainties associated with these analyses. (3) Determine whether the potential for microbes warrants a feed to TSPA-LA to account for predicted effects on repository performance. (4) Provide information to address the ''Yucca Mountain Review Plan, Final Report'' (NUREG-1804) (NRC 2003 [DIRS 163274]) and Key Technical Issues and agreements, as appropriate. (5) Develop information for inclusion or exclusion of FEPs.

  4. Combustion chemistry. Activities in the CHEC research programme

    Energy Technology Data Exchange (ETDEWEB)

    Dam-Johansen, K.; Johnsson, J.E.; Glarborg, P.; Frandsen, F.; Jensen, A.; Oestberg, M. [Technical Univ. of Denmark, Dept. of Chemical Engineering, Lyngby (Denmark)

    1996-12-01

    The combustion chemistry in the oxidation of fossil fuels and biofuels determines together with mixing and heat transfer the required size of a furnace, the emission of gaseous pollutants, and the formation of ash and deposits on surfaces. This paper describes technologies for solid fuels combustion and gives a summary of the fuels, the pollutant chemistry and the inorganic chemistry in combustion processes. Emphasis is put on the work carried out in the CHEC (Combustion and Harmful Emission Control Research Programme). (au) 173 refs.

  5. How to Organise the Chemistry Classroom in a Student-Active Mode

    NARCIS (Netherlands)

    Eilks, I.; Prins, G.T.; Lazarowitz, R.

    2013-01-01

    Everyday, chemistry teachers all over the world are challenged by the question: Should I explain the chemistry content in a frontal mode using the blackboard, or am I able to apply methods to activate the students learning on their own terms? This chapter is based on the premise that learning

  6. How to Organise the Chemistry Classroom in a Student-Active Mode

    NARCIS (Netherlands)

    Eilks, I.; Prins, G.T.; Lazarowitz, R.

    2013-01-01

    Everyday, chemistry teachers all over the world are challenged by the question: Should I explain the chemistry content in a frontal mode using the blackboard, or am I able to apply methods to activate the students learning on their own terms? This chapter is based on the premise that learning proces

  7. Comparative Analysis of Click Chemistry Mediated Activity-Based Protein Profiling in Cell Lysates

    Directory of Open Access Journals (Sweden)

    Yinliang Yang

    2013-10-01

    Full Text Available Activity-based protein profiling uses chemical probes that covalently attach to active enzyme targets. Probes with conventional tags have disadvantages, such as limited cell permeability or steric hindrance around the reactive group. A tandem labeling strategy with click chemistry is now widely used to study enzyme targets in situ and in vivo. Herein, the probes are reacted in live cells, whereas the ensuing detection by click chemistry takes place in cell lysates. We here make a comparison of the efficiency of the activity-based tandem labeling strategy by using Cu(I-catalyzed and strain-promoted click chemistry, different ligands and different lysis conditions.

  8. Recent progress in understanding activity cliffs and their utility in medicinal chemistry.

    Science.gov (United States)

    Stumpfe, Dagmar; Hu, Ye; Dimova, Dilyana; Bajorath, Jürgen

    2014-01-09

    The activity cliff concept is of high relevance for medicinal chemistry. Recent studies are discussed that have further refined our understanding of activity cliffs and suggested different ways of exploiting activity cliff information. These include alternative approaches to define and classify activity cliffs in two and three dimensions, data mining investigations to systematically detect all possible activity cliffs, the introduction of computational methods to predict activity cliffs, and studies designed to explore activity cliff progression in medicinal chemistry. The discussion of these studies is complemented with new findings revealing the frequency of activity cliff formation when different molecular representations are used and the distribution of activity cliffs across different targets. Taken together, the results have a number of implications for the practice of medicinal chemistry.

  9. Chemistry, physico-chemistry and applications linked to biological activities of β-glucans.

    Science.gov (United States)

    Barsanti, Laura; Passarelli, Vincenzo; Evangelista, Valtere; Frassanito, Anna Maria; Gualtieri, Paolo

    2011-03-01

    β-Glucans is the common name given to a group of chemically heterogeneous polysaccharides. They are long- or short-chain polymers of (1-->3)-β-linked glucose moieties which may be branched, with the branching chains linked to the backbone by a (1-->6)-β linkage. β-(1-->3)-Glucans are widely distributed in bacteria, algae, fungi and plants, where they are involved in cell wall structure and other biological function. β-Glucans have been shown to provide a remarkable range of health benefits, and are especially important against the two most common conventional causes of death in industrialized countries, i.e. cardiovascular diseases (where they promote healthy cholesterol and blood glucose levels) and cancer (where they enhance immune system functions). This Highlight provides a comprehensive and up-to-date commentary on β-glucans, their chemistry, physico-chemistry, functional role in immunological responses, and possible applications as therapeutic tools. In addition, we discuss the mechanism behind their health benefits, which are not yet fully understood.

  10. Incorporating More Individual Accountability in Group Activities in General Chemistry

    Science.gov (United States)

    Cox, Charles T., Jr.

    2015-01-01

    A modified model of cooperative learning known as the GIG model (for group-individual-group) designed and implemented in a large enrollment freshman chemistry course. The goal of the model is to establish a cooperative environment while emphasizing greater individual accountability using both group and individual assignments. The assignments were…

  11. Chemistry Notes

    Science.gov (United States)

    School Science Review, 1976

    1976-01-01

    Described are eight chemistry experiments and demonstrations applicable to introductory chemistry courses. Activities include: measure of lattice enthalpy, Le Chatelier's principle, decarboxylation of soap, use of pocket calculators in pH measurement, and making nylon. (SL)

  12. Heterocyclic chemistry

    OpenAIRE

    Hemming, Karl

    2011-01-01

    Recent progress in the synthesis of heterocyclic compounds is presented\\ud 2010 offered highlights in pericyclic chemistry, particularly 1,3-dipolar cycloaddition chemistry, asymmetric synthesis, gold catalysis, organocatalysis, hydroamination, C–H activation and multicomponent reactions.

  13. Liaison activities with the Institute of Physical Chemistry, Russian Academy of Sciences: FY 1997

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, C.H.; Elovich, R.J.

    1997-09-01

    The Institute of Physical Chemistry of the Russian Academy of Sciences is conducting a program of fundamental and applied research into the chemistry of the actinides and technetium in alkaline media such as are present in the Hanford Site underground waste storage tanks. This work is being coordinated and the results disseminated through a technical liaison maintained at the Pacific Northwest National Laboratory. The technical liaison is performing laboratory studies on plutonium chemistry in alkaline media. The activities at the Institute of Physical Chemistry and through the liaison are pursued to improve understanding of the chemical behavior of key long-lived radioactive elements under current operating and proposed tank waste processing conditions. Both activities are supported by the Efficient Separations and Processing Crosscutting Program under the Office of Science and Technology of the U.S. Department of Energy.

  14. Combinatorial chemistry

    DEFF Research Database (Denmark)

    Nielsen, John

    1994-01-01

    An overview of combinatorial chemistry is presented. Combinatorial chemistry, sometimes referred to as `irrational drug design,' involves the generation of molecular diversity. The resulting chemical library is then screened for biologically active compounds.......An overview of combinatorial chemistry is presented. Combinatorial chemistry, sometimes referred to as `irrational drug design,' involves the generation of molecular diversity. The resulting chemical library is then screened for biologically active compounds....

  15. Combinatorial chemistry

    DEFF Research Database (Denmark)

    Nielsen, John

    1994-01-01

    An overview of combinatorial chemistry is presented. Combinatorial chemistry, sometimes referred to as `irrational drug design,' involves the generation of molecular diversity. The resulting chemical library is then screened for biologically active compounds.......An overview of combinatorial chemistry is presented. Combinatorial chemistry, sometimes referred to as `irrational drug design,' involves the generation of molecular diversity. The resulting chemical library is then screened for biologically active compounds....

  16. The sequence of learning cycle activities in high school chemistry

    Science.gov (United States)

    Abraham, Michael R.; Renner, John W.

    The sequence of the three phases of two high school learning cycles in chemistry was altered in order to: (I ) give insights into the factors which account for the success of the learning cycle, (2) serve as an indirect test of the association between Piaget's theory and the learning cycle, and (3) to compare the learning cycle with traditional instruction. Each of the six sequences (one n o d and five altered) was studied with content and atritudc measures. The outcomes of the study supported the contention that the normal learning cycle sequence is the optimum sequence for achievement of content knowledge.

  17. CASE METHOD. ACTIVE LEARNING METHODOLOGY TO ACQUIRE SIGNIFICANT IN CHEMISTRY

    Directory of Open Access Journals (Sweden)

    Clotilde Pizarro

    2015-09-01

    Full Text Available In this paper the methodology of cases in first year students of the Engineering Risk Prevention and Environment is applied. For this purpose a real case of contamination occurred at a school in the region of Valparaiso called "La Greda" is presented. If the application starts delivering an extract of the information collected from the media and they made a brief induction on the methodology to be applied. A plenary session, which is debate about possible solutions to the problem and establishing a relationship between the case and drives the chemistry program is then performed. Is concluded that the application of the case method, was a fruitful tool in yields obtained by students, since the percentage of approval was 75%, which is considerably higher than previous years.

  18. Using Laboratory Chemicals to Imitate Illicit Drugs in a Forensic Chemistry Activity

    Science.gov (United States)

    Hasan, Shawn; Bromfield-Lee, Deborah; Oliver-Hoyo, Maria T.; Cintron-Maldonado, Jose A.

    2008-01-01

    This forensic chemistry activity utilizes presumptive forensic testing procedures and laboratory chemicals that produce screening results similar to controlled substances. For obvious reasons, obtaining heavily regulated controlled substances to create an undergraduate student activity is not practical for most educational institutions. We were…

  19. Offering Community Engagement Activities to Increase Chemistry Knowledge and Confidence for Teachers and Students

    Science.gov (United States)

    Sewry, Joyce D.; Glover, Sarah R.; Harrison, Timothy G.; Shallcross, Dudley E.; Ngcoza, Kenneth M.

    2014-01-01

    Given the emphasis on community engagement in higher education, academic departments need to become more involved in the community. This paper discusses a number of outreach activities undertaken by the chemistry department at Rhodes University, South Africa. The activities range from service learning to community engagement with teachers and…

  20. Investigating the Effectiveness of an Analogy Activity in Improving Students' Conceptual Change for Solution Chemistry Concepts

    Science.gov (United States)

    Calik, Muammer; Ayas, Alipasa; Coll, Richard K.

    2009-01-01

    This paper reports on an investigation on the use of an analogy activity and seeks to provide evidence of whether the activity enables students to change alternative conceptions towards views more in accord with scientific views for aspects of solution chemistry. We were also interested in how robust any change was and whether these changes in…

  1. Using Laboratory Chemicals to Imitate Illicit Drugs in a Forensic Chemistry Activity

    Science.gov (United States)

    Hasan, Shawn; Bromfield-Lee, Deborah; Oliver-Hoyo, Maria T.; Cintron-Maldonado, Jose A.

    2008-01-01

    This forensic chemistry activity utilizes presumptive forensic testing procedures and laboratory chemicals that produce screening results similar to controlled substances. For obvious reasons, obtaining heavily regulated controlled substances to create an undergraduate student activity is not practical for most educational institutions. We were…

  2. Current parallel chemistry principles and practice: application to the discovery of biologically active molecules.

    Science.gov (United States)

    Edwards, Paul J

    2009-11-01

    This article describes the use of parallel chemistry techniques for drug discovery, based on publications from January 2006 to December 2008. Chemical libraries that yielded active compounds across a range of biological targets are presented, together with synthetic details when appropriate. Background information for the biological targets involved and any SAR that could be discerned within members of a library series also is discussed. New technological developments, as applied to library design and synthesis and, more generally, in the discovery of biologically active entities, are highlighted. In addition, the likely future directions for parallel chemistry in its ability to impact upon drug discovery are also presented.

  3. Students' Perceptions of Teaching in Context-based and Traditional Chemistry Classrooms: Comparing content, learning activities, and interpersonal perspectives

    Science.gov (United States)

    Overman, Michelle; Vermunt, Jan D.; Meijer, Paulien C.; Bulte, Astrid M. W.; Brekelmans, Mieke

    2014-07-01

    Context-based curriculum reforms in chemistry education are thought to bring greater diversity to the ways in which chemistry teachers organize their teaching. First and foremost, students are expected to perceive this diversity. However, empirical research on how students perceive their teacher's teaching in context-based chemistry classrooms, and whether this teaching differs from traditional chemistry lessons, is scarce. This study aims to develop our understanding of what teaching looks like, according to students, in context-based chemistry classrooms compared with traditional chemistry classrooms. As such, it might also provide a better understanding of whether teachers implement and attain the intentions of curriculum developers. To study teacher behaviour we used three theoretical perspectives deemed to be important for student learning: a content perspective, a learning activities perspective, and an interpersonal perspective. Data were collected from 480 students in 24 secondary chemistry classes in the Netherlands. Our findings suggest that, according to the students, the changes in teaching in context-based chemistry classrooms imply a lessening of the emphasis on fundamental chemistry and the use of a teacher-centred approach, compared with traditional chemistry classrooms. However, teachers in context-based chemistry classrooms seem not to display more 'context-based' teaching behaviour, such as emphasizing the relation between chemistry, technology, and society and using a student-centred approach. Furthermore, students in context-based chemistry classrooms perceive their teachers as having less interpersonal control and showing less affiliation than teachers in traditional chemistry classrooms. Our findings should be interpreted in the context of former and daily experiences of both teachers and students. As only chemistry is reformed in the schools in which context-based chemistry is implemented, it is challenging for both students and teachers to

  4. Chemistry Technology

    Data.gov (United States)

    Federal Laboratory Consortium — Chemistry technology experts at NCATS engage in a variety of innovative translational research activities, including:Design of bioactive small molecules.Development...

  5. Eliciting Metacognitive Experiences and Reflection in a Year 11 Chemistry Classroom: An Activity Theory Perspective

    Science.gov (United States)

    Thomas, Gregory P.; McRobbie, Campbell J.

    2013-06-01

    Concerns regarding students' learning and reasoning in chemistry classrooms are well documented. Students' reasoning in chemistry should be characterized by conscious consideration of chemical phenomenon from laboratory work at macroscopic, molecular/sub-micro and symbolic levels. Further, students should develop metacognition in relation to such ways of reasoning about chemistry phenomena. Classroom change eliciting metacognitive experiences and metacognitive reflection is necessary to shift entrenched views of teaching and learning in students. In this study, Activity Theory is used as the framework for interpreting changes to the rules/customs and tools of the activity systems of two different classes of students taught by the same teacher, Frances, who was teaching chemical equilibrium to those classes in consecutive years. An interpretive methodology involving multiple data sources was employed. Frances explicitly changed her pedagogy in the second year to direct students attention to increasingly consider chemical phenomena at the molecular/sub-micro level. Additionally, she asked students not to use the textbook until toward the end of the equilibrium unit and sought to engage them in using their prior knowledge of chemistry to understand their observations from experiments. Frances' changed pedagogy elicited metacognitive experiences and reflection in students and challenged them to reconsider their metacognitive beliefs about learning chemistry and how it might be achieved. While teacher change is essential for science education reform, students are not passive players in change efforts and they need to be convinced of the viability of teacher pedagogical change in the context of their goals, intentions, and beliefs.

  6. Fuzzy electron density fragments in macromolecular quantum chemistry, combinatorial quantum chemistry, functional group analysis, and shape-activity relations.

    Science.gov (United States)

    Mezey, Paul G

    2014-09-16

    Conspectus Just as complete molecules have no boundaries and have "fuzzy" electron density clouds approaching zero density exponentially at large distances from the nearest nucleus, a physically justified choice for electron density fragments exhibits similar behavior. Whereas fuzzy electron densities, just as any fuzzy object, such as a thicker cloud on a foggy day, do not lend themselves to easy visualization, one may partially overcome this by using isocontours. Whereas a faithful representation of the complete fuzzy density would need infinitely many such isocontours, nevertheless, by choosing a selected few, one can still obtain a limited pictorial representation. Clearly, such images are of limited value, and one better relies on more complete mathematical representations, using, for example, density matrices of fuzzy fragment densities. A fuzzy density fragmentation can be obtained in an exactly additive way, using the output from any of the common quantum chemical computational techniques, such as Hartree-Fock, MP2, and various density functional approaches. Such "fuzzy" electron density fragments properly represented have proven to be useful in a rather wide range of applications, for example, (a) using them as additive building blocks leading to efficient linear scaling macromolecular quantum chemistry computational techniques, (b) the study of quantum chemical functional groups, (c) using approximate fuzzy fragment information as allowed by the holographic electron density theorem, (d) the study of correlations between local shape and activity, including through-bond and through-space components of interactions between parts of molecules and relations between local molecular shape and substituent effects, (e) using them as tools of density matrix extrapolation in conformational changes, (f) physically valid averaging and statistical distribution of several local electron densities of common stoichiometry, useful in electron density databank mining, for

  7. Learning Activity Package, Chemistry I. LAP Numbers 22, 23, 24, 25, 26, 27, and 28.

    Science.gov (United States)

    Jones, Naomi

    As a set of seven Learning Activity Packages (LAPs) for individualized instruction in chemistry, the units cover the unit system, matter, energy, atomic structures, chemical formulas, physical states of matter, solutions and suspensions, ionization, acids, bases, and salts. Each unit contains a rationale for the material; a list of behavioral…

  8. Structure activity study on the quinone/quinone methide chemistry of flavonoids

    NARCIS (Netherlands)

    Awad, H.M.; Boersma, M.G.; Boeren, S.; Bladeren, van P.J.; Vervoort, J.; Rietjens, I.M.C.M.

    2001-01-01

    A structure-activity study on the quinone/quinone methide chemistry of a series of 3',4'-dihydroxyflavonoids was performed. Using the glutathione trapping method followed by HPLC, 1H NMR, MALDI-TOF, and LC/MS analysis to identify the glutathionyl adducts, the chemical behavior of the

  9. Structure activity study on the quinone/quinone methide chemistry of flavonoids

    NARCIS (Netherlands)

    Awad, H.M.; Boersma, M.G.; Boeren, S.; Bladeren, van P.J.; Vervoort, J.; Rietjens, I.M.C.M.

    2001-01-01

    A structure-activity study on the quinone/quinone methide chemistry of a series of 3',4'-dihydroxyflavonoids was performed. Using the glutathione trapping method followed by HPLC, 1H NMR, MALDI-TOF, and LC/MS analysis to identify the glutathionyl adducts, the chemical behavior of the quinones/quinon

  10. Substrate Activity Screening (SAS) and Related Approaches in Medicinal Chemistry.

    Science.gov (United States)

    Gladysz, Rafaela; Lambeir, Anne-Marie; Joossens, Jurgen; Augustyns, Koen; Van der Veken, Pieter

    2016-03-04

    Substrate activity screening (SAS) was presented a decade ago by Ellman and co-workers as a straightforward methodology for the identification of fragment-sized building blocks for enzyme inhibitors. Ever since, SAS and variations derived from it have been successfully applied to the discovery of inhibitors of various families of enzymatically active drug targets. This review covers key achievements and challenges of SAS and related methodologies, including the modified substrate activity screening (MSAS) approach. Special attention is given to the kinetic and thermodynamic aspects of these methodologies, as a thorough understanding thereof is crucial for successfully transforming the identified fragment-sized hits into potent inhibitors.

  11. Allosteric activation of membrane-bound glutamate receptors using coordination chemistry within living cells

    Science.gov (United States)

    Kiyonaka, Shigeki; Kubota, Ryou; Michibata, Yukiko; Sakakura, Masayoshi; Takahashi, Hideo; Numata, Tomohiro; Inoue, Ryuji; Yuzaki, Michisuke; Hamachi, Itaru

    2016-10-01

    The controlled activation of proteins in living cells is an important goal in protein-design research, but to introduce an artificial activation switch into membrane proteins through rational design is a significant challenge because of the structural and functional complexity of such proteins. Here we report the allosteric activation of two types of membrane-bound neurotransmitter receptors, the ion-channel type and the G-protein-coupled glutamate receptors, using coordination chemistry in living cells. The high programmability of coordination chemistry enabled two His mutations, which act as an artificial allosteric site, to be semirationally incorporated in the vicinity of the ligand-binding pockets. Binding of Pd(2,2‧-bipyridine) at the allosteric site enabled the active conformations of the glutamate receptors to be stabilized. Using this approach, we were able to activate selectively a mutant glutamate receptor in live neurons, which initiated a subsequent signal-transduction pathway.

  12. Applications of organoboron compounds in carbohydrate chemistry and glycobiology: analysis, separation, protection, and activation.

    Science.gov (United States)

    McClary, Corey A; Taylor, Mark S

    2013-11-15

    The reversible covalent interactions between organoboron compounds and diols have been applied for many years in carbohydrate chemistry. They form the basis of efficient methods for the detection of carbohydrates, and applications in cellular imaging and glycoprotein analysis are beginning to emerge. The interactions are also of widespread utility in carbohydrate synthesis: depending upon the coordination geometry at boron, either protection or activation of a bound diol motif may be achieved. This review article uses recent examples to illustrate the breadth of applications of organoboron compounds in carbohydrate chemistry.

  13. Chemistry and Biological Activities of Flavonoids: An Overview

    Directory of Open Access Journals (Sweden)

    Shashank Kumar

    2013-01-01

    Full Text Available There has been increasing interest in the research on flavonoids from plant sources because of their versatile health benefits reported in various epidemiological studies. Since flavonoids are directly associated with human dietary ingredients and health, there is need to evaluate structure and function relationship. The bioavailability, metabolism, and biological activity of flavonoids depend upon the configuration, total number of hydroxyl groups, and substitution of functional groups about their nuclear structure. Fruits and vegetables are the main dietary sources of flavonoids for humans, along with tea and wine. Most recent researches have focused on the health aspects of flavonoids for humans. Many flavonoids are shown to have antioxidative activity, free radical scavenging capacity, coronary heart disease prevention, hepatoprotective, anti-inflammatory, and anticancer activities, while some flavonoids exhibit potential antiviral activities. In plant systems, flavonoids help in combating oxidative stress and act as growth regulators. For pharmaceutical purposes cost-effective bulk production of different types of flavonoids has been made possible with the help of microbial biotechnology. This review highlights the structural features of flavonoids, their beneficial roles in human health, and significance in plants as well as their microbial production.

  14. Thapsigargin, origin, chemistry, structure-activity relationships and prodrug development

    DEFF Research Database (Denmark)

    Doan, Thi Quynh Nhu; Christensen, Søren Brøgger

    2015-01-01

    Thapsigargin was originally isolated from the roots of the Mediterranean umbelliferous plant Thapsia garganica in order to characterize the skin irritant principle. The biological activity was related to the subnanomolar affinity for the sarco-endoplasmic reticulum calcium ATPase. Prolonged inhib...

  15. Chemistry and biological activities of flavonoids: an overview.

    Science.gov (United States)

    Kumar, Shashank; Pandey, Abhay K

    2013-01-01

    There has been increasing interest in the research on flavonoids from plant sources because of their versatile health benefits reported in various epidemiological studies. Since flavonoids are directly associated with human dietary ingredients and health, there is need to evaluate structure and function relationship. The bioavailability, metabolism, and biological activity of flavonoids depend upon the configuration, total number of hydroxyl groups, and substitution of functional groups about their nuclear structure. Fruits and vegetables are the main dietary sources of flavonoids for humans, along with tea and wine. Most recent researches have focused on the health aspects of flavonoids for humans. Many flavonoids are shown to have antioxidative activity, free radical scavenging capacity, coronary heart disease prevention, hepatoprotective, anti-inflammatory, and anticancer activities, while some flavonoids exhibit potential antiviral activities. In plant systems, flavonoids help in combating oxidative stress and act as growth regulators. For pharmaceutical purposes cost-effective bulk production of different types of flavonoids has been made possible with the help of microbial biotechnology. This review highlights the structural features of flavonoids, their beneficial roles in human health, and significance in plants as well as their microbial production.

  16. Adsorption of atrazine on hemp stem-based activated carbons with different surface chemistry

    OpenAIRE

    Lupul, Iwona; Yperman, Jan; Carleer, Robert; Gryglewicz, Grazyna

    2015-01-01

    Surface-modified hemp stem-based activated carbons (HACs) were prepared and used for the adsorption of atrazine from aqueous solution, and their adsorption performance was examined. A series of HACs were prepared by potassium hydroxide activation of hemp stems, followed by subsequent modification by thermal annealing, oxidation with nitric acid and amination. The resultant HACs differed in surface chemistry, while possessing similar porous structure. The surface group characteristics were exa...

  17. Weapons in disguise--activating mechanisms and protecting group chemistry in nature.

    Science.gov (United States)

    Kwan, Jason C; Luesch, Hendrik

    2010-11-22

    Bioactive natural products often possess uniquely functionalized structures with unusual modes of action; however, the natural product itself is not always the active species. We discuss molecules that draw on protecting group chemistry or else require activation to unmask reactive centers, illustrating that nature is not only a source of complex structures but also a guide for elegant chemical transformations which provides ingenious chemical solutions for drug delivery.

  18. [Research progress of chemistry and anti-cancer activities of natural products from Chinese Garcinia plants].

    Science.gov (United States)

    Fu, Wen-Wei; Tan, Hong-Sheng; Xu, Hong-Xi

    2014-02-01

    Garcinia plants are one of the rich sources of natural xanthones and benzophenones which have attracted a great deal of attention from the scientists in the fields of chemistry and pharmacology. Recently, many structurally unique constituents with various bioactivities, especially anti-tumor activity, have been isolated from Garcinia plants. This concise review focused on the anti-cancer activity natural products isolated from Chinese Garcinia plants, and the research finding by authors and collaborators over the past several years were cited.

  19. Study the active site of flavonoid applying radiation chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jilan; Sun Gang; Zhang Fugen; He Yongke; Li Jiuqiang [Department of Technical Physics, Peking Univ., Beijing (China)

    2000-03-01

    Flavonoid are a large and important class of naturally occurring, low molecular weight benzo-{gamma}-pyrone derivatives which are reported to have a myriad of biological activities, but the study on the active sites of flavonoids is still ambiguous. In this paper, rutin, quercetin and baicalin have been selected as model compounds. It is well known that rutin is used in inhibiting arteriosclerosis and baicalin is antibacterial and antiviral. They have similar basic structure, but their medicinal properties are so different, why? As most flavonoids contain carbonyl group, which can capture electron effectively, we predict that flavonoids can capture electron to form radical anion. The formation of anion radical may have influence on the mitochondrial electron transport chain. The difference in the ability of forming anion radical may cause the difference in their medicinal effects. (author)

  20. Electrostatic activation of prebiotic chemistry in substellar atmospheres

    CERN Document Server

    Stark, Craig R; Diver, Declan A; Rimmer, Paul B

    2013-01-01

    Charged dust grains in the atmospheres of exoplanets may play a key role in the formation of prebiotic molecules, necessary to the origin of life. Dust grains submerged in an atmospheric plasma become negatively charged and attract a flux of ions that are accelerated from the plasma. The energy of the ions upon reaching the grain surface may be sufficient to overcome the activation energy of particular chemical reactions that would be unattainable via ion and neutral bombardment from classical, thermal excitation. As a result, prebiotic molecules or their precursors could be synthesised on the surface of dust grains that form clouds in exoplanetary atmospheres. This paper investigates the energization of the plasma ions, and the dependence on the plasma electron temperature, in the atmospheres of substellar objects such as gas giant planets. Calculations show that modest electron temperatures of $\\approx 1$ eV ($\\approx 10^{4}$ K) are enough to accelerate ions to sufficient energies that exceed the activation...

  1. Chemistry and Biological Activities of Flavonoids: An Overview

    OpenAIRE

    Shashank Kumar; Pandey, Abhay K

    2013-01-01

    There has been increasing interest in the research on flavonoids from plant sources because of their versatile health benefits reported in various epidemiological studies. Since flavonoids are directly associated with human dietary ingredients and health, there is need to evaluate structure and function relationship. The bioavailability, metabolism, and biological activity of flavonoids depend upon the configuration, total number of hydroxyl groups, and substitution of functional groups about...

  2. Amazon acai: chemistry and biological activities: a review.

    Science.gov (United States)

    Yamaguchi, Klenicy Kazumy de Lima; Pereira, Luiz Felipe Ravazi; Lamarão, Carlos Victor; Lima, Emerson Silva; da Veiga-Junior, Valdir Florêncio

    2015-07-15

    Acai (acai or assai) is one of the Amazon's most popular functional foods and widely used in the world. There are many benefits to its alleged use in the growing market for nutraceuticals. The acai extracts have a range of polyphenolic components with antioxidant properties, some of those present in greater quantity are orientin, isoorientin and vanillic acid, as well as anthocyanins cyanidin-3-glucoside and cyanidin-3-rutinoside. The presence of these substances is linked mainly to the antioxidant, anti- inflammatory, anti-proliferative and cardioprotective activities. Importantly, there are two main species of the Euterpe genus which produce acai. There are several differences between them but they are still quite unknown, from literature to producers and consumers. In this review are highlighted the chemical composition, botanical aspects, pharmacological, marketing and nutrition of these species based on studies published in the last five years in order to unify the current knowledge and dissimilarities between them.

  3. Computational Chemistry Approach to Interpret the Crystal Violet Adsorption on Golbasi Lignite Activated Carbon

    Science.gov (United States)

    Depci, Tolga; Sarikaya, Musa; Prisbrey, Keith A.; Yucel, Aysegul

    2016-10-01

    In this paper, adsorption mechanism of Crystal Violet (CV) dye from the aqueous solution on the activated carbon prepared from Golbasi lignite was explained and interpreted by a computational chemistry approach and experimental studies. Molecular dynamic simulations and Ab initio frontier orbital analysis indicated relatively high energy and electron transfer processes during adsorption, and molecular dynamics simulations showed CV dye molecules moving around on the activated carbon surface after adsorption, facilitating penetration into cracks and pores. The experimental results supported to molecular dynamic simulation and showed that the monolayer coverage occurred on the activated carbon surface and each CV dye ion had equal sorption activation energy.

  4. Coriander (Coriandrum sativum L. essential oil: Chemistry and biological activity

    Directory of Open Access Journals (Sweden)

    Shyamapada Mandal

    2015-06-01

    Full Text Available Coriandrum sativum L. (C. sativum is one of the most useful essential oil bearing spices as well as medicinal plants, belonging to the family Umbelliferae/Apiaceae. The leaves and seeds of the plant are widely used in folk medicine in addition to its use as a seasoning in food preparation. The C. sativum essential oil and extracts possess promising antibacterial, antifungal and anti-oxidative activities as various chemical components in different parts of the plant, which thus play a great role in maintaining the shelf-life of foods by preventing their spoilage. This edible plant is non-toxic to humans, and the C. sativum essential oil is thus used in different ways, viz., in foods (like flavouring and preservatives and in pharmaceutical products (therapeutic action as well as in perfumes (fragancias and lotions. The current updates on the usefulness of the plant C. sativum are due to scientific research published in different web-based journals.

  5. Chemistry in the Molecular Disks of Active Galactic Nuclei

    Science.gov (United States)

    Harada, Nanase; Herbst, Eric

    2010-06-01

    Active galactic nuclei (AGNs) are the centers of galaxies with supermassive blackholes whose accretion of mass causes very high luminosities of L˜1044-46erg s-1. An accretion disk has a molecular component that extends to hundreds of pc from the central AGN core. The question of how much central illumination affects the disk and how much star formation is present near the core have been astrophysical interests. Rotational lines from these disks at a sub-kpc scale have been observed for molecules such as CO, HCO+, HCN, and HNC. When ALMA becomes fully operational, it will be able to resolve these disks at much higher resolution than currently. Molecular observations at higher resolution may give some hints on the physics in the molecular disk. We modeled the chemical composition of a molecular disk in an AGN on a scale of tens of pc. To do this, we extended our standard gas-phase OSU network to include important processes at much higher temperatures, approaching 1000 K. We used the density model of Thompson et al., and determined the temperature by the blackbody approximation from the luminosity of the AGN core. The ionization by X-rays from the AGN core, by cosmic-rays from the AGN core, supernovae and stellar winds, and by UV-photons from OB stars are considered. We will briefly mention the effects from other factors that may change the molecular abundances such as shock waves and inhomogeneity of the density of the disk. T. Thompson, E. Quataert, and N. Murray, Astrophysical J. 630, 167 (2005)

  6. Textbook Questions in Context-Based and Traditional Chemistry Curricula Analysed from a Content Perspective and a Learning Activities Perspective

    Science.gov (United States)

    Overman, Michelle; Vermunt, Jan D.; Meijer, Paulien C.; Bulte, Astrid M. W.; Brekelmans, Mieke

    2013-01-01

    In this study, questions in context-based and traditional chemistry textbooks were analysed from two perspectives that are at the heart of chemistry curricula reforms: a content perspective and a learning activities perspective. To analyse these textbook questions, we developed an instrument for each perspective. In total, 971 textbook questions…

  7. The application of click chemistry in the synthesis of agents with anticancer activity

    Directory of Open Access Journals (Sweden)

    Ma N

    2015-03-01

    Full Text Available Nan Ma,1–3 Ying Wang,3 Bing-Xin Zhao,3 Wen-Cai Ye,1,3 Sheng Jiang2 1Department of Natural Medicinal Chemistry, China Pharmaceutical University, Nanjing, 2Laboratory of Medicinal Chemistry, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, 3Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, People’s Republic of China Abstract: The copper(I-catalyzed 1,3-dipolar cycloaddition between alkynes and azides (click chemistry to form 1,2,3-triazoles is the most popular reaction due to its reliability, specificity, and biocompatibility. This reaction has the potential to shorten procedures, and render more efficient lead identification and optimization procedures in medicinal chemistry, which is a powerful modular synthetic approach toward the assembly of new molecular entities and has been applied in anticancer drugs discovery increasingly. The present review focuses mainly on the applications of this reaction in the field of synthesis of agents with anticancer activity, which are divided into four groups: topoisomerase II inhibitors, histone deacetylase inhibitors, protein tyrosine kinase inhibitors, and antimicrotubule agents. Keywords: topoisomerase II inhibitors, histone deacetylase inhibitors, protein tyrosine kinase inhibitors, antimicrotubule agents

  8. Hot Chemistry Laboratory decommissioning activities at IPEN/CNEN-SP, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Camilo, Ruth L.; Lainetti, Paulo E.O. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: rcamilo@ipen.br, e-mail: lainetti@ipen.br

    2009-07-01

    IPEN's fuel cycle activities were accomplished in laboratory and pilot plant scale and most facilities were built in the 70-80 years. Nevertheless, radical changes of the Brazilian nuclear policy in the beginning of 90's determined the interruption of several fuel cycle activities and facilities shutdown. Since then, IPEN has faced the problem of the pilot plants decommissioning considering that there was no experience/expertise in this field at all. In spite of this, some laboratory and pilot plant decommissioning activities have been performed in IPEN in the last years, even without previous experience and training support. One of the first decommissioning activities accomplished in IPEN involved the Hot Chemistry Laboratory. This facility was built in the beginning of the 80's with the proposal of supporting research and development in the nuclear chemistry area. It was decided to settle a new laboratory in the place where the Hot Chemistry Laboratory was installed, being necessary its total releasing from the radioactive contamination point of view. The previous work in the laboratory involved the manipulation of samples of irradiated nuclear fuel, besides plutonium-239 and uranium-233 standard solutions. There were 5 glove-boxes in the facility but only 3 were used with radioactive material. The glove-boxes contained several devices and materials, besides the radioactive compounds, such as: electric and electronic equipment, metallic and plastic pieces, chemical reagents, liquid and solid radioactive wastes, etc. The laboratory's decommissioning process was divided in 12 steps. This paper describes the procedures, problems faced and results related to the Hot Chemistry Laboratory decommissioning operations and its reintegration as a new laboratory of the Chemical and Environmental Technology Center (CQMA) - IPEN-CNEN/SP. (author)

  9. Diversity of Secondary Metabolites from Marine Bacillus Species: Chemistry and Biological Activity

    Directory of Open Access Journals (Sweden)

    Hee Jae Shin

    2013-08-01

    Full Text Available Marine Bacillus species produce versatile secondary metabolites including lipopeptides, polypeptides, macrolactones, fatty acids, polyketides, and isocoumarins. These structurally diverse compounds exhibit a wide range of biological activities, such as antimicrobial, anticancer, and antialgal activities. Some marine Bacillus strains can detoxify heavy metals through reduction processes and have the ability to produce carotenoids. The present article reviews the chemistry and biological activities of secondary metabolites from marine isolates. Side by side, the potential for application of these novel natural products from marine Bacillus strains as drugs, pesticides, carotenoids, and tools for the bioremediation of heavy metal toxicity are also discussed.

  10. A review on biological sources, chemistry and pharmacological activities of pinostrobin.

    Science.gov (United States)

    Patel, Neeraj K; Jaiswal, Gaurav; Bhutani, Kamlesh K

    2016-09-01

    Pinostrobin, a dietary bioflavonoid discovered more than 6 decades ago in the heart-wood of pine (Pinus strobus), has depicted many pharmacological activities including anti-viral, anti-oxidant, anti-leukaemic, anti-inflammatory and anti-aromatase activities. It is an inhibitor of sodium channel and Ca(2+) signalling pathways and also inhibits intestinal smooth muscle contractions. In spite of the fact that pinostrobin has an application as functional foods, till-to-date no comprehensive review on pinostrobin has been carried out. Hence, the present review deals with the biological sources, chemistry and pharmacological activities of pinostrobin.

  11. New Concept of C–H and C–C Bond Activation via Surface Organometallic Chemistry

    KAUST Repository

    Samantaray, Manoja

    2015-08-18

    In this chapter we describe the recent applications of well-defined oxidesupported metal alkyls/alkylidenes/alkylidynes and hydrides of group IV, V, and VI transition metals in the field of C–H and C–C bond activation. The activation of ubiquitous C–H and C–C bonds of paraffin is a long-standing challenge because of intrinsic low reactivity. There are many concepts derived from surface organometallic chemistry (SOMC): surface organometallic fragments are always intermediates in heterogeneous catalysis. The study of their synthesis and reactivity is a way to rationalize mechanism of heterogeneous catalysis and to achieve structure activity relationship. By surface organometallic chemistry one can enter any catalytic center by a reaction intermediate leading in fine to single site catalysts. With surface organometallic chemistry one can coordinate to the metal which can play a role in different elementary steps leading for example to C–H activation and Olefin metathesis. Because of the development of SOMC there is a lot of space for the improvement of homogeneous catalysis. After the 1997 discovery of alkane metathesis using silica-supported tantalum hydride by Basset et al. at low temperature (150ºC) the focus in this area was shifted to the discovery of more and more challenging surface complexes active in the application of C–H and C–C bond activation. Here we describe the evolution of well-defined metathesis catalyst with time as well as the effect of support on catalysis. We also describe here which metal–ligand combinations are responsible for a variety of C–H and C–C bond activation.

  12. Adsorption of anionic and cationic dyes on activated carbons with different surface chemistries.

    Science.gov (United States)

    Faria, P C C; Orfão, J J M; Pereira, M F R

    2004-04-01

    The influence of the surface chemical groups of an activated carbon on the removal of different classes of dyes is evaluated. Starting from the same material (NORIT GAC 1240 PLUS), the following treatments were carried out in order to produce a series of samples with different surface chemical properties but with no major differences in their textural properties: oxidation in the liquid phase with 6M HNO(3) and 10 M H(2)O(2) (acid materials) and heat treatment at 700 degrees C in H(2) or N(2) flow (basic materials). The specific micropores volume and mesopores surface area of the materials were obtained from N(2) adsorption equilibrium isotherms at 77K. The surface chemistry was characterised by temperature programmed desorption, by the determination of the point of zero charge (pH(pzc)) and by the evaluation of the acidity/basicity of the samples. Elemental and proximate analyses were also carried out. Equilibrium isotherms of selected dyes (an acid, a basic and a reactive dye) on the mentioned samples were obtained and the results discussed in relation to their surface chemistry. In general, the Langmuir model provided the best fit for the adsorption data. It is shown that the surface chemistry of the activated carbon plays a key role in dye adsorption performance. The basic sample obtained by thermal treatment under H(2) flow at 700 degrees C is the best material for the adsorption of all the tested dyes.

  13. The application of click chemistry in the synthesis of agents with anticancer activity.

    Science.gov (United States)

    Ma, Nan; Wang, Ying; Zhao, Bing-Xin; Ye, Wen-Cai; Jiang, Sheng

    2015-01-01

    The copper(I)-catalyzed 1,3-dipolar cycloaddition between alkynes and azides (click chemistry) to form 1,2,3-triazoles is the most popular reaction due to its reliability, specificity, and biocompatibility. This reaction has the potential to shorten procedures, and render more efficient lead identification and optimization procedures in medicinal chemistry, which is a powerful modular synthetic approach toward the assembly of new molecular entities and has been applied in anticancer drugs discovery increasingly. The present review focuses mainly on the applications of this reaction in the field of synthesis of agents with anticancer activity, which are divided into four groups: topoisomerase II inhibitors, histone deacetylase inhibitors, protein tyrosine kinase inhibitors, and antimicrotubule agents.

  14. The chemistry and biological activity of heterocycle-fused quinolinone derivatives: A review.

    Science.gov (United States)

    Shiro, Tomoya; Fukaya, Takayuki; Tobe, Masanori

    2015-06-05

    Among all heterocycles, the heterocycle-fused quinolinone scaffold is one of the privileged structures in drug discovery as heterocycle-fused quinolinone derivatives exhibit various biological activities allowing them to act as anti-inflammatory, anticancer, antidiabetic, and antipsychotic agents. This wide spectrum of biological activity has attracted a great deal of attention in the field of medicinal chemistry. In this review, we provide a comprehensive description of the biological and pharmacological properties of various heterocycle-fused quinolinone scaffolds and discuss the synthetic methods of some of their derivatives.

  15. Antiproliferative Activity of Polyether Antibiotic--Cinchona Alkaloid Conjugates Obtained via Click Chemistry.

    Science.gov (United States)

    Skiera, Iwona; Antoszczak, Michał; Trynda, Justyna; Wietrzyk, Joanna; Boratyński, Przemysław; Kacprzak, Karol; Huczyński, Adam

    2015-10-01

    A series of eight new conjugates of salinomycin or monensin and Cinchona alkaloids were obtained by the Cu(I)-catalysed 1,3-dipolar Huisgen cycloaddition (click chemistry) of respective N-propargyl amides of salinomycin or monensin with four different Cinchona alkaloid derived azides. In vitro antiproliferative activity of these conjugates evaluated against three cancer cell lines (LoVo, LoVo/DX, HepG2) showed that four of the compounds exhibited high antiproliferative activity (IC50 below 3.00 μm) and appeared to be less toxic and more selective against normal cells than two standard anticancer drugs.

  16. Chemically active colloids near osmotic-responsive walls with surface-chemistry gradients

    Science.gov (United States)

    Popescu, M. N.; Uspal, W. E.; Dietrich, S.

    2017-04-01

    Chemically active colloids move by creating gradients in the composition of the surrounding solution and by exploiting the differences in their interactions with the various molecular species in solution. If such particles move near boundaries, e.g. the walls of the container confining the suspension, gradients in the composition of the solution are also created along the wall. This give rise to chemi-osmosis (via the interactions of the wall with the molecular species forming the solution), which drives flows coupling back to the colloid and thus influences its motility. Employing an approximate ‘point-particle’ analysis, we show analytically that—owing to this kind of induced active response (chemi-osmosis) of the wall—such chemically active colloids can align with, and follow, gradients in the surface chemistry of the wall. In this sense, these artificial ‘swimmers’ exhibit a primitive form of thigmotaxis with the meaning of sensing the proximity of a (not necessarily discontinuous) physical change in the environment. We show that the alignment with the surface-chemistry gradient is generic for chemically active colloids as long as they exhibit motility in an unbounded fluid, i.e. this phenomenon does not depend on the exact details of the propulsion mechanism. The results are discussed in the context of simple models of chemical activity, corresponding to Janus particles with ‘source’ chemical reactions on one half of the surface and either ‘inert’ or ‘sink’ reactions over the other half.

  17. Chemically active colloids near osmotic-responsive walls with surface-chemistry gradients.

    Science.gov (United States)

    Popescu, M N; Uspal, W E; Dietrich, S

    2017-04-05

    Chemically active colloids move by creating gradients in the composition of the surrounding solution and by exploiting the differences in their interactions with the various molecular species in solution. If such particles move near boundaries, e.g. the walls of the container confining the suspension, gradients in the composition of the solution are also created along the wall. This give rise to chemi-osmosis (via the interactions of the wall with the molecular species forming the solution), which drives flows coupling back to the colloid and thus influences its motility. Employing an approximate 'point-particle' analysis, we show analytically that-owing to this kind of induced active response (chemi-osmosis) of the wall-such chemically active colloids can align with, and follow, gradients in the surface chemistry of the wall. In this sense, these artificial 'swimmers' exhibit a primitive form of thigmotaxis with the meaning of sensing the proximity of a (not necessarily discontinuous) physical change in the environment. We show that the alignment with the surface-chemistry gradient is generic for chemically active colloids as long as they exhibit motility in an unbounded fluid, i.e. this phenomenon does not depend on the exact details of the propulsion mechanism. The results are discussed in the context of simple models of chemical activity, corresponding to Janus particles with 'source' chemical reactions on one half of the surface and either 'inert' or 'sink' reactions over the other half.

  18. Nuclear Chemistry.

    Science.gov (United States)

    Chemical and Engineering News, 1979

    1979-01-01

    Provides a brief review of the latest developments in nuclear chemistry. Nuclear research today is directed toward increased activity in radiopharmaceuticals and formation of new isotopes by high-energy, heavy-ion collisions. (Author/BB)

  19. Effects of steam activation on the pore structure and surface chemistry of activated carbon derived from bamboo waste

    Science.gov (United States)

    Zhang, Yan-Juan; Xing, Zhen-Jiao; Duan, Zheng-Kang; Li, Meng; Wang, Yin

    2014-10-01

    The effects of steam activation on the pore structure evolution and surface chemistry of activated carbon (AC) obtained from bamboo waste were investigated. Nitrogen adsorption-desorption isotherms revealed that higher steam activation temperatures and/or times promoted the creation of new micropores and widened the existing micropores, consequently decreasing the surface area and total pore volume. Optimum conditions included an activation temperature of 850 °C, activation time of 120 min, and steam flush generated from deionized water of 0.2 cm3 min-1. Under these conditions, AC with a BET surface area of 1210 m2 g-1 and total pore volume of 0.542 cm-3 g-1was obtained. Changes in surface chemistry were determined through Boehm titration, pH measurement, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Results revealed the presence of a large number of basic groups on the surface of the pyrolyzed char and AC. Steam activation did not affect the species of oxygen-containing groups but changed the contents of these species when compared with pyrolyzed char. Scanning electron microscopy was used to observe the surface morphology of the products. AC obtained under optimum conditions showed a monolayer adsorption capacity of 330 mg g-1 for methylene blue (MB), which demonstrates its excellent potential for MB adsorption applications.

  20. Effects of steam activation on the pore structure and surface chemistry of activated carbon derived from bamboo waste

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yan-Juan [School of Chemical Engineering, Xiangtan University, Xiangtan 411105 (China); Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 36102 (China); Xing, Zhen-Jiao [Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 36102 (China); Duan, Zheng-Kang [School of Chemical Engineering, Xiangtan University, Xiangtan 411105 (China); Meng Li [Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 36102 (China); Wang, Yin, E-mail: yinwang@iue.ac.cn [Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 36102 (China)

    2014-10-01

    The effects of steam activation on the pore structure evolution and surface chemistry of activated carbon (AC) obtained from bamboo waste were investigated. Nitrogen adsorption–desorption isotherms revealed that higher steam activation temperatures and/or times promoted the creation of new micropores and widened the existing micropores, consequently decreasing the surface area and total pore volume. Optimum conditions included an activation temperature of 850 °C, activation time of 120 min, and steam flush generated from deionized water of 0.2 cm{sup 3} min{sup −1}. Under these conditions, AC with a BET surface area of 1210 m{sup 2} g{sup −1} and total pore volume of 0.542 cm{sup −3} g{sup −1}was obtained. Changes in surface chemistry were determined through Boehm titration, pH measurement, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Results revealed the presence of a large number of basic groups on the surface of the pyrolyzed char and AC. Steam activation did not affect the species of oxygen-containing groups but changed the contents of these species when compared with pyrolyzed char. Scanning electron microscopy was used to observe the surface morphology of the products. AC obtained under optimum conditions showed a monolayer adsorption capacity of 330 mg g{sup −1} for methylene blue (MB), which demonstrates its excellent potential for MB adsorption applications.

  1. FEATURES OF STUDENTS’ PROJECT-RESEARCH ACTIVITY IN CHEMISTRY LESSON OF PROFILE SCHOOL

    Directory of Open Access Journals (Sweden)

    Maria D. Tukalo

    2012-01-01

    Full Text Available The article presents a characterization of projects method; includes the main approaches and methods of study the project methodology as one of the best examples of the formation and development of life competencies of students in the study of chemistry in profile school; presents the key motivational characteristics to enhance the subjects of learning interest in  their cognitive and practical activity, the formation of their independence, creative self-development of students using computer based applications in the system of modern learning environment to output to a new technological level of the whole educational system.

  2. LAS0811: From Combinatorial Chemistry to Activation of Antioxidant Response Element

    OpenAIRE

    Ming Zhu; Hyounggee Baek; Ruiwu Liu; Aimin Song; Kit Lam; Derick Lau

    2009-01-01

    The antioxidant response element (ARE) and its transcription factor, nuclear factor-erythroid 2 p45-related factor 2 (Nrf2), are potential targets for cancer chemoprevention. We sought to screen small molecules synthesized with combinatorial chemistry for activation of ARE. By high-throughput screening of 9400 small molecules from 10 combinatorial chemical libraries using HepG2 cells with an ARE-driven reporter, we have identified a novel small molecule, 1,2-dimethoxy-4,5-dinitrobenzene (LAS0...

  3. Enhanced ozone loss by active inorganic bromine chemistry in the tropical troposphere

    Science.gov (United States)

    Le Breton, Michael; Bannan, Thomas J.; Shallcross, Dudley E.; Khan, M. Anwar; Evans, Mathew J.; Lee, James; Lidster, Richard; Andrews, Stephen; Carpenter, Lucy J.; Schmidt, Johan; Jacob, Daniel; Harris, Neil R. P.; Bauguitte, Stephane; Gallagher, Martin; Bacak, Asan; Leather, Kimberley E.; Percival, Carl J.

    2017-04-01

    Bromine chemistry, particularly in the tropics, has been suggested to play an important role in tropospheric ozone loss although a lack of measurements of active bromine species impedes a quantitative understanding of its impacts. Recent modelling and measurements of bromine monoxide (BrO) by Wang et al. (2015) have shown current models under predict BrO concentrations over the Pacific Ocean and allude to a missing source of BrO. Here, we present the first simultaneous aircraft measurements of atmospheric bromine monoxide, BrO (a radical that along with atomic Br catalytically destroys ozone) and the inorganic Br precursor compounds HOBr, BrCl and Br2 over the Western Pacific Ocean from 0.5 to 7 km. The presence of 0.17-1.64 pptv BrO and 3.6-8 pptv total inorganic Br from these four species throughout the troposphere causes 10-20% of total ozone loss, and confirms the importance of bromine chemistry in the tropical troposphere; contributing to a 6 ppb decrease in ozone levels due to halogen chemistry. Observations are compared with a global chemical transport model and find that the observed high levels of BrO, BrCl and HOBr can be reconciled by active multiphase oxidation of halide (Br- and Cl-) by HOBr and ozone in cloud droplets and aerosols. Measurements indicate that 99% of the instantaneous free Br in the troposphere up to 8 km originates from inorganic halogen photolysis rather than from photolysis of organobromine species.

  4. Chemically active colloids near osmotic-responsive walls with surface-chemistry gradients

    CERN Document Server

    Popescu, M N; Dietrich, S

    2016-01-01

    Chemically active colloids move by creating gradients in the composition of the surrounding solution and by exploiting the differences in their interactions with the various molecular species in solution. If such particles move near boundaries, e.g., the walls of the container confining the suspension, gradients in the composition of the solution are also created along the wall. This give rise to chemi-osmosis (via the interactions of the wall with the molecular species forming the solution), which drives flows coupling back to the colloid and thus influences its motility. Employing an approximate "point-particle" analysis, we show analytically that -- owing to this kind of induced active response (chemi-osmosis) of the wall -- such chemically active colloids can align with, and follow, gradients in the surface chemistry of the wall. In this sense, these artificial "swimmers" exhibit a primitive form of thigmotaxis with the meaning of sensing the proximity of a (not necessarily discontinuous) physical change ...

  5. Xanthomicrol: a comprehensive review of its chemistry, distribution, biosynthesis and pharmacological activity.

    Science.gov (United States)

    Fattahi, Mohammad; Cusido, Rosa M; Khojasteh, Abbas; Bonfill, Mercedes; Palazon, Javier

    2014-01-01

    Highly methoxylated flavones, which have known potential as cancer chemopreventive agents, accumulate on the leaf surfaces of some plant species and their physiological role is to protect the plant against harmful UV radiation. Xanthomicrol is one of the methoxylated flavones currently attracting most attention from researchers worldwide because of its promising pharmacological activities, including anti-spasmodic, anti-platelet and anti-cancer effects, among others. This review covers the chemistry and biological origin, distribution and pharmacological activity of xanthomicrol. Knowledge of the botanical distribution of this compound will not only encourage the use of plant sources for pharmacological purposes, but will also serve as a reference in the search for this valuable flavonoid in another genus or family. New approaches to xanthomicrol production are also described, including biotechnological attempts to develop xanthomicrol-producing plant cell factories.

  6. The Importance of Computer Based Active Learning for Basic Chemistry in Vocational High Schools

    Directory of Open Access Journals (Sweden)

    Tuğçe GÜNTER

    2011-01-01

    Full Text Available Chemistry is a very comprehensive discipline that researches atoms; molecules; the structure of matter in the form of element or compound; combinations, and physical and chemical properties of matter; macroscopic and microscopic transformations of matters; the energy and entropy released or absorbed in the course of these transformations; the structures and functions of carbohydrates, lipids, proteins, enzymes, vitamins and minerals in the body. This discipline includes numerous reactions at the macroscopic, microscopic and particulate levels, abstract concepts, three-dimensional structure of molecules, mathematics, and graphics. It is important for students to be trained as scientists to internalize -with meaningful learning - chemistry having much abstract concepts. Especially for students in associate degree programs in Vocational High Schools, taking this integrated course will provide them to be more creative in their future professional work; to cope with and overcome analytical problems; to be self-learners; to fill the gaps concerning chemical analysis originated from secondary education; and to gain critical thinking and self-evaluation skills regarding chemical problems. In the age of developing science and technology, “Computer-Based Active Learning Method” emerged with the introduction of multi-media into education and training. In this context, students will learn difficult and complex mathematical operations and graphics interpretations more meaningfully with computer-based simulations and analogies.

  7. Hydrothermal activity in the Lau back-arc basin: Sulfides and water chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Fouquet, Y.; Charlou, J.L.; Donval, J.P.; Foucher, J.P. (Institut Francais de Recherche et d' Exploitation de la Mer, Plouzane (France)); von Stackelberg, U.; Wiedicke, M. (Bundesanstalt fur Geowissenschaften und Rohstoffe, Hannover (Germany)); Erzinger, J. (Justus-Liebig-Universitat, Giessen (Germany)); Herzig, P. (Rheinish-Westfalische Technische Hochschule, Aachen (Germany)); Muhe, R. (Universitat Kiel (Germany)); Soakai, S. (Ministry of Lands Survey and Natural Resources, Nuku' Alofa (Tonga)); Whitechurch, H. (Ecole et Observatoire de Physique du Globe de Strasbourg (France))

    1991-04-01

    The submersible Nautile completed 22 dives during the Nautilau cruise (R/V Nadir, April 17-May 10, 1989) for a detailed investigation of the southern Lau basin near Tonga. The objective of the scientific team from France, Germany, and Tonga was to understand the process of sea-floor ore formation associated with hydrothermal circulation along the Valu Fa back-arc ridge behind the Tonga-Kermadec trench. The four diving areas, between lat21{degree}25'S and 22{degree}40'S in water{approximately}2000 m deep, were selected on the basis of results from cruises of the R/V Jean Charcot and R/V Sonne. The Nadir cruise provided proof of hydrothermal activity-in all for areas, over more than 100 km-as indicated by the widespread occurence of hydrothermal deposits and by heat flow, conductivity, and temperature measurements near the sea bottom. The most spectacular findings were high-temperature white and black smokers and associated fauna and ore deposits. Hydrothermal water chemistry and sulfide composition data presented here indicate that this hydrothermal field is very different from the hydrothermal fields in oceanic ridges. This difference is seen in water chemistry of the hydrothermal fluid (pH=2 and high metal content) and the chemical composition of sulfides (enrichment in Ba, As, and Pb).

  8. Tracing the Physical Conditions in Active Galactic Nuclei with Time-Dependent Chemistry

    CERN Document Server

    Meijerink, Rowin; Kamp, Inga; Aresu, Giambattista; Thi, Wing-Fai; Woitke, Peter

    2013-01-01

    We present an extension of the code ProDiMo that allows for a modeling of processes pertinent to active galactic nuclei and to an ambient chemistry that is time dependent. We present a proof-of-concept and focus on a few astrophysically relevant species, e.g., H+, H2+ and H3+; C+ and N+; C and O; CO and H2O; OH+, H2O+ and H3O+; HCN and HCO+. We find that the freeze-out of water is strongly suppressed and that this affects the bulk of the oxygen and carbon chemistry occurring in AGN. The commonly used AGN tracer HCN/HCO+ is strongly time-dependent, with ratios that vary over orders of magnitude for times longer than 10^4 years. Through ALMA observations this ratio can be used to probe how the narrow-line region evolves under large fluctuations in the SMBH accretion rate. Strong evolutionary trends, on time scales of 10^4-10^8 years, are also found in species such as H3O+, CO, and H2O. These reflect, respectively, time dependent effects in the ionization balance, the transient nature of the production of molecu...

  9. LAS0811: From Combinatorial Chemistry to Activation of Antioxidant Response Element

    Directory of Open Access Journals (Sweden)

    Ming Zhu

    2009-01-01

    Full Text Available The antioxidant response element (ARE and its transcription factor, nuclear factor-erythroid 2 p45-related factor 2 (Nrf2, are potential targets for cancer chemoprevention. We sought to screen small molecules synthesized with combinatorial chemistry for activation of ARE. By high-throughput screening of 9400 small molecules from 10 combinatorial chemical libraries using HepG2 cells with an ARE-driven reporter, we have identified a novel small molecule, 1,2-dimethoxy-4,5-dinitrobenzene (LAS0811, as an activator of the ARE. LAS0811 upregulated the activity of NAD(PH:quinone oxidoreductase 1 (NQO1, a representative antioxidative enzyme regulated by ARE. It enhanced production of an endogenous reducing agent, glutathione (GSH. In addition, LAS0811 induced expression of heme oxygenase 1 (HO1, which is an ARE-regulated enzyme with anti-inflammatory activity. Furthermore, LAS0811 reduced cell death due to the cytotoxic stress of a strong oxidant, t-butyl hydroperoxide (t-BOOH. Mechanistically, LAS0811 upregulated the expression of Nrf2 and promoted its translocation into the nuclei leading to subsequent ARE activation. Taken together, LAS0811 is a novel activator of the ARE and its associated detoxifying genes and, thus, a potential agent for cancer chemoprevention.

  10. Final Report: Main Group Element Chemistry in Service of Hydrogen Storage and Activation

    Energy Technology Data Exchange (ETDEWEB)

    David A. Dixon; Anthony J. Arduengo, III

    2010-09-30

    goal was met in terms of reducing the number of costly experiments and helping to focus the experimental effort on the potentially optimal targets. We have used computational chemistry approaches to predict the thermodynamic properties of a wide range of compounds containing boron, nitrogen, hydrogen, and other elements as appropriate including carbon. These calculations were done in most cases with high level molecular orbital theory methods that have small error bars on the order of ± 1 to 2 kcal/mol. The results were used to benchmark more approximate methods such as density functional theory for larger systems and for database development. We predicted reliable thermodynamics for thousands of compounds for release and regeneration schemes to aid/guide materials design and process design and simulation. These are the first reliable computed values for these compounds and for many represent the only available values. Overall, the computational results have provided us with new insights into the chemistry of main group and organic-base chemical hydrogen systems from the release of hydrogen to the regeneration of spent fuel. A number of experimental accomplishments were also made in this project. The experimental work on hydrogen storage materials centered on activated polarized σ- or π-bonded frameworks that hold the potential for ready dihydrogen activation, uptake, and eventually release. To this end, a large number of non-traditional valence systems including carbenes, cyanocarbons, and C-B and and B-N systems were synthesized and examined. During the course of these studies an important lead arose from the novel valency of a class of stable organic singlet bi-radical systems. A synthetic strategy to an “endless” hydrogen storage polymer has been developed based on our cyanocarbon chemistry. A key issue with the synthetic efforts was being able to link the kinetics of release with the size of the substituents as it was difficult to develop a low molecular

  11. Aerosol physicochemical effects on CCN activation simulated with the chemistry-climate model EMAC

    Science.gov (United States)

    Chang, D. Y.; Lelieveld, J.; Tost, H.; Steil, B.; Pozzer, A.; Yoon, J.

    2017-08-01

    This study uses the EMAC atmospheric chemistry-climate model to simulate cloud properties with a prognostic cloud droplet nucleation scheme. We present modeled global distributions of cloud condensation nuclei (CCN) number concentrations and CCN activation rates, together with the effective hygroscopicity parameter κ, to describe the aerosol chemical composition effect on CCN activation. Large particles can easily activate into cloud droplets, even at low κ values due to the dominant size effect in cloud droplet formation. Small particles are less efficiently activated as CCN, and are more sensitive to aerosol composition and supersaturation. Since the dominant fraction of small particles generally originates from anthropogenic precursor emissions over land, this study focuses on the influence of the continental atmosphere, using a prognostic cloud droplet nucleation scheme that considers aerosol-cloud interactions during cloud formation, together with a double-moment cloud microphysics scheme. The agreement of simulated clouds and climate with observations generally improves over the Northern Hemisphere continents, particularly high air pollution regions such as Eastern US, Europe, East Asia by accounting for aerosol-cloud interactions that include impacts of chemical composition on CCN activation.

  12. Colorful Chemistry

    Science.gov (United States)

    Sullivan, P. Teal; Carsten Conner, L. D.; Guthrie, Mareca; Pompea, Stephen; Tsurusaki, Blakely K.; Tzou, Carrie

    2017-01-01

    This article describes a chemistry/art activity that originated in an National Science Foundation--funded two-week STEAM (Science, Technology, Engineering, Art, and Math) academy for grade 4-6 girls. The authors recommend using this investigation in conjunction with other activities focusing on chemical change as a step toward fulfilling the…

  13. Final Report: Main Group Element Chemistry in Service of Hydrogen Storage and Activation

    Energy Technology Data Exchange (ETDEWEB)

    David A. Dixon; Anthony J. Arduengo, III

    2010-09-30

    goal was met in terms of reducing the number of costly experiments and helping to focus the experimental effort on the potentially optimal targets. We have used computational chemistry approaches to predict the thermodynamic properties of a wide range of compounds containing boron, nitrogen, hydrogen, and other elements as appropriate including carbon. These calculations were done in most cases with high level molecular orbital theory methods that have small error bars on the order of ± 1 to 2 kcal/mol. The results were used to benchmark more approximate methods such as density functional theory for larger systems and for database development. We predicted reliable thermodynamics for thousands of compounds for release and regeneration schemes to aid/guide materials design and process design and simulation. These are the first reliable computed values for these compounds and for many represent the only available values. Overall, the computational results have provided us with new insights into the chemistry of main group and organic-base chemical hydrogen systems from the release of hydrogen to the regeneration of spent fuel. A number of experimental accomplishments were also made in this project. The experimental work on hydrogen storage materials centered on activated polarized σ- or π-bonded frameworks that hold the potential for ready dihydrogen activation, uptake, and eventually release. To this end, a large number of non-traditional valence systems including carbenes, cyanocarbons, and C-B and and B-N systems were synthesized and examined. During the course of these studies an important lead arose from the novel valency of a class of stable organic singlet bi-radical systems. A synthetic strategy to an “endless” hydrogen storage polymer has been developed based on our cyanocarbon chemistry. A key issue with the synthetic efforts was being able to link the kinetics of release with the size of the substituents as it was difficult to develop a low molecular

  14. Synthesis and amylin receptor activity of glycomimetics of pramlintide using click chemistry.

    Science.gov (United States)

    Yule, Lauren R; Bower, Rebekah L; Kaur, Harveen; Kowalczyk, Renata; Hay, Debbie L; Brimble, Margaret A

    2016-06-21

    Pramlintide (Symlin®), a synthetic analogue of the neuroendocrine hormone amylin, is devoid of the tendency to form cytotoxic amyloid fibrils and is currently used in patients with type I and type II diabetes mellitus as an adjunctive therapy with insulin or insulin analogues. As part of an on-going search for a pramlintide analogue with improved pharmacokinetic properties, we herein report the synthesis of mono- and di-glycosylated analogues of pramlintide and their activity at the AMY1(a) receptor. Introduction of N-glycosylated amino acids into the pramlintide sequence afforded the native N-linked glycomimetics whilst use of Cu(i)-catalysed azide-alkyne 1,3-dipolar cycloaddition (click) chemistry delivered 1,2,3-triazole linked glycomimetics. AMY1(a) receptor activity was retained by incorporation of single or multiple GlcNAc moieties at positions 21 and 35 of native pramlintide. Importantly, no difference in AMY1(a) activity was observed between native N-linked glycomimetics and 1,2,3-triazole linked glycomimetics demonstrating that the click variants can act as surrogates for the native N-glycosides in a biological setting.

  15. Understanding the chemistry behind the antioxidant activities of butylated hydroxytoluene (BHT): a review.

    Science.gov (United States)

    Yehye, Wageeh A; Rahman, Noorsaadah Abdul; Ariffin, Azhar; Abd Hamid, Sharifah Bee; Alhadi, Abeer A; Kadir, Farkaad A; Yaeghoobi, Marzieh

    2015-08-28

    Hindered phenols find a wide variety of applications across many different industry sectors. Butylated hydroxytoluene (BHT) is a most commonly used antioxidant recognized as safe for use in foods containing fats, pharmaceuticals, petroleum products, rubber and oil industries. In the past two decades, there has been growing interest in finding novel antioxidants to meet the requirements of these industries. To accelerate the antioxidant discovery process, researchers have designed and synthesized a series of BHT derivatives targeting to improve its antioxidant properties to be having a wide range of antioxidant activities markedly enhanced radical scavenging ability and other physical properties. Accordingly, some structure-activity relationships and rational design strategies for antioxidants based on BHT structure have been suggested and applied in practice. We have identified 14 very sensitive parameters, which may play a major role on the antioxidant performance of BHT. In this review, we attempt to summarize the current knowledge on this topic, which is of significance in selecting and designing novel antioxidants using a well-known antioxidant BHT as a building-block molecule. Our strategy involved investigation on understanding the chemistry behind the antioxidant activities of BHT, whether through hydrogen or electron transfer mechanism to enable promising anti-oxidant candidates to be synthesized. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  16. A proposal for teaching undergraduate chemistry students carbohydrate biochemistry by problem-based learning activities.

    Science.gov (United States)

    Figueira, Angela C M; Rocha, Joao B T

    2014-01-01

    This article presents a problem-based learning (PBL) approach to teaching elementary biochemistry to undergraduate students. The activity was based on "the foods we eat." It was used to engage students' curiosity and to initiate learning about a subject that could be used by the future teachers in the high school. The experimental activities (8-12 hours) were related to the questions: (i) what does the Benedict's Reagent detect? and (ii) What is determined by glucose oxidase (GOD)? We also ask the students to compare the results with those obtained with the Lugol reagent, which detects starch. Usually, students inferred that the Benedict reagent detects reducing sugars, while GOD could be used to detect glucose. However, in GOD assay, an open question was left, because the results could be due to contamination of the sugars (particularly galactose) with glucose. Though not stressed, GOD does not oxidize the carbohydrates tested and all the positive results are due to contamination. The activities presented here can be easily done in the high school, because they are simple and non-expensive. Furthermore, in the case of Benedict reaction, it is possible to follow the reduction of Cu (II) "macroscopically" by following the formation of the brick-orange precipitate. The concrete observation of a chemical reaction can motivate and facilitate students understanding about chemistry of life.

  17. High pressure chemistry of red phosphorus by photo-activated simple molecules

    Science.gov (United States)

    Ceppatelli, M.; Fanetti, S.; Bini, R.; Caporali, M.; Peruzzini, M.

    2014-05-01

    High pressure (HP) is very effective in reducing intermolecular distances and inducing unexpected chemical reactions. In addition the photo-activation of the reactants in HP conditions can lead to very efficient and selective processes. The chemistry of phosphorus is currently based on the white molecular form. The red polymeric allotrope, despite more stable and much less toxic, has not attracted much attention so far. However, switching from the white to the red form would benefit any industrial procedure, especially from an environmental point of view. On the other side, water and ethanol are renewable, environmental friendly and largely available molecules, usable as reactants and photo-activators in HP conditions. Here we report a study on the HP photo-induced reactivity of red phosphorus with water and ethanol, showing the possibility of very efficient and selective processes, leading to molecular hydrogen and valuable phosphorus compounds. The reactions have been studied by means of FTIR and Raman spectroscopy and pressure has been generated using membrane Diamond (DAC) and Sapphire (SAC) anvil cells. HP reactivity has been activated by the two-photon absorption of near-UV wavelengths and occurred in total absence of solvents, catalysts and radical initiators, at room T and mild pressure conditions (0.2-1.5 GPa).

  18. Porous structure and surface chemistry of phosphoric acid activated carbon from corncob

    Energy Technology Data Exchange (ETDEWEB)

    Sych, N.V.; Trofymenko, S.I.; Poddubnaya, O.I.; Tsyba, M.M. [Institute for Sorption and Endoecology Problems, National Academy of Sciences of Ukraine, 13 General Naumov St., 03164 Kyiv (Ukraine); Sapsay, V.I.; Klymchuk, D.O. [M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine, 2 Tereshchenkivska St., 01601 Kyiv (Ukraine); Puziy, A.M., E-mail: alexander.puziy@ispe.kiev.ua [Institute for Sorption and Endoecology Problems, National Academy of Sciences of Ukraine, 13 General Naumov St., 03164 Kyiv (Ukraine)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Phosphoric acid activation results in formation of carbons with acidic surface groups. Black-Right-Pointing-Pointer Maximum amount of surface groups is introduced at impregnation ratio 1.25. Black-Right-Pointing-Pointer Phosphoric acid activated carbons show high capacity to copper. Black-Right-Pointing-Pointer Phosphoric acid activated carbons are predominantly microporous. Black-Right-Pointing-Pointer Maximum surface area and pore volume achieved at impregnation ratio 1.0. - Abstract: Active carbons have been prepared from corncob using chemical activation with phosphoric acid at 400 Degree-Sign C using varied ratio of impregnation (RI). Porous structure of carbons was characterized by nitrogen adsorption and scanning electron microscopy. Surface chemistry was studied by IR and potentiometric titration method. It has been shown that porosity development was peaked at RI = 1.0 (S{sub BET} = 2081 m{sup 2}/g, V{sub tot} = 1.1 cm{sup 3}/g), while maximum amount of acid surface groups was observed at RI = 1.25. Acid surface groups of phosphoric acid activated carbons from corncob includes phosphate and strongly acidic carboxylic (pK = 2.0-2.6), weakly acidic carboxylic (pK = 4.7-5.0), enol/lactone (pK = 6.7-7.4; 8.8-9.4) and phenol (pK = 10.1-10.7). Corncob derived carbons showed high adsorption capacity to copper, especially at low pH. Maximum adsorption of methylene blue and iodine was observed for carbon with most developed porosity (RI = 1.0).

  19. The Use of Molecular Modeling as "Pseudoexperimental" Data for Teaching VSEPR as a Hands-On General Chemistry Activity

    Science.gov (United States)

    Martin, Christopher B.; Vandehoef, Crissie; Cook, Allison

    2015-01-01

    A hands-on activity appropriate for first-semester general chemistry students is presented that combines traditional VSEPR methods of predicting molecular geometries with introductory use of molecular modeling. Students analyze a series of previously calculated output files consisting of several molecules each in various geometries. Each structure…

  20. Removal of Aromatic Pollutant Surrogate from Water by Recyclable Magnetite-Activated Carbon Nanocomposite: An Experiment for General Chemistry

    Science.gov (United States)

    Furlan, Ping Y.; Melcer, Michael E.

    2014-01-01

    A general chemistry laboratory experiment using readily available chemicals is described to introduce college students to an exciting class of nanocomposite materials. In a one-step room temperature synthetic process, magnetite nanoparticles are embedded onto activated carbon matrix. The resultant nanocomposite has been shown to combine the…

  1. The Use of Molecular Modeling as "Pseudoexperimental" Data for Teaching VSEPR as a Hands-On General Chemistry Activity

    Science.gov (United States)

    Martin, Christopher B.; Vandehoef, Crissie; Cook, Allison

    2015-01-01

    A hands-on activity appropriate for first-semester general chemistry students is presented that combines traditional VSEPR methods of predicting molecular geometries with introductory use of molecular modeling. Students analyze a series of previously calculated output files consisting of several molecules each in various geometries. Each structure…

  2. Teaching with the Case Study Method to Promote Active Learning in a Small Molecule Crystallography Course for Chemistry Students

    Science.gov (United States)

    Campbell, Michael G.; Powers, Tamara M.; Zheng, Shao-Liang

    2016-01-01

    Implementing the case study method in a practical X-ray crystallography course designed for graduate or upper-level undergraduate chemistry students is described. Compared with a traditional lecture format, assigning small groups of students to examine literature case studies encourages more active engagement with the course material and…

  3. Eliciting Metacognitive Experiences and Reflection in a Year 11 Chemistry Classroom: An Activity Theory Perspective

    Science.gov (United States)

    Thomas, Gregory P.; McRobbie, Campbell J.

    2013-01-01

    Concerns regarding students' learning and reasoning in chemistry classrooms are well documented. Students' reasoning in chemistry should be characterized by conscious consideration of chemical phenomenon from laboratory work at macroscopic, molecular/sub-micro and symbolic levels. Further, students should develop metacognition in relation to such…

  4. Design and evaluation of digital activating learning materials for Food Chemistry education.

    NARCIS (Netherlands)

    Diederen, J.

    2005-01-01

    Food chemistry is amongst others about the components and chemical reactions that are part of food products, about the effect of chemical reactions on the quality and about the techniques used to research food products. To support students in acquiring the knowledge and skills of food chemistry, in

  5. Invited award contribution for ACS Award in Inorganic Chemistry. Geometric and electronic structure contributions to function in bioinorganic chemistry: active sites in non-heme iron enzymes.

    Science.gov (United States)

    Solomon, E I

    2001-07-16

    Spectroscopy has played a major role in the definition of structure/function correlations in bioinorganic chemistry. The importance of spectroscopy combined with electronic structure calculations is clearly demonstrated by the non-heme iron enzymes. Many members of this large class of enzymes activate dioxygen using a ferrous active site that has generally been difficult to study with most spectroscopic methods. A new spectroscopic methodology has been developed utilizing variable temperature, variable field magnetic circular dichroism, which enables one to obtain detailed insight into the geometric and electronic structure of the non-heme ferrous active site and probe its reaction mechanism on a molecular level. This spectroscopic methodology is presented and applied to a number of key mononuclear non-heme iron enzymes leading to a general mechanistic strategy for O2 activation. These studies are then extended to consider the new features present in the binuclear non-heme iron enzymes and applied to understand (1) the mechanism of the two electron/coupled proton transfer to dioxygen binding to a single iron center in hemerythrin and (2) structure/function correlations over the oxygen-activating enzymes stearoyl-ACP Delta9-desaturase, ribonucleotide reductase, and methane monooxygenase. Electronic structure/reactivity correlations for O2 activation by non-heme relative to heme iron enzymes will also be developed.

  6. Quantum chemistry calculation-aided structural optimization of combretastatin A-4-like tubulin polymerization inhibitors: improved stability and biological activity.

    Science.gov (United States)

    Jiang, Junhang; Zheng, Canhui; Zhu, Kongkai; Liu, Jia; Sun, Nannan; Wang, Chongqing; Jiang, Hualiang; Zhu, Ju; Luo, Cheng; Zhou, Youjun

    2015-03-12

    A potent combretastatin A-4 (CA-4) like tubulin polymerization inhibitor 22b was found with strong antitumor activity previously. However, it easily undergoes cis-trans isomerization under natural light, and the resulting decrease in activity limits its further applications. In this study, we used quantum chemistry calculations to explore the molecular basis of its instability. Aided by the calculations, two rounds of structural optimization of 22b were conducted. Accelerated quantitative light stability testing confirmed that the stability of these designed compounds was significantly improved as predicted. Among them, compounds 1 and 3b displayed more potent inhibitory activity on tumor cell growth than 22b. In addition, the potent in vivo antitumor activity of compound 1 was confirmed. Quantum chemistry calculations were used in the optimization of stilbene-like molecules, providing new insight into stilbenoid optimization and important implications for the future development of novel CA-4-like tubulin polymerization inhibitors.

  7. Take-Home Challenges: Extending Discovery-Based Activities beyond the General Chemistry Classroom

    Science.gov (United States)

    Mason, P. K.; Sarquis, A. M.

    1996-04-01

    In an effort to more effectively integrate the experimental nature of chemistry into our students' experiences, we are developing and implementing discovery-based activities into both the laboratory and lecture components of general chemistry. Below we describe and provide an example of a "take-home challenge" intended to supplement the lecture component of the course. These take-home challenges involve the student in chemistry exploration outside of class and extend the context of content and experimentation into a nontraditional laboratory environment. Over 25 take-home challenges have been developed to date. Preliminary evaluation of the impact of the take-home challenges shows that students reporting themselves as receiving a B or C grade in the course find the challenges very useful in helping them gain a conceptual understanding of the phenomena addressed. Students earning an A grade report little or no impact on their learning. Prepared as one-page handouts, each take-home challenge begins with a scene-setting introduction followed by pertinent background information, a list of materials to be collected, and any appropriate safety precautions. The exploration component of the activity integrates leading questions with the procedural instructions to help guide the students through the discovery process and challenge them to stretch their understanding of the chemistry. After completing a take-home challenge activity, students submit written reports containing responses to the questions posed, observations of data collected, and their responses to the challenge. The accompanying sample take-home challenge activity is provided as a novel adaptation of the belch phenomenon that challenges students to experiment in order to explain the factors that account for the observed behavior. Persons interested in field testing the take-home challenges with their classes should contact the authors. Belch Bottle Challenge: What factors are responsible for the behavior of a

  8. Inhibitors of VIM-2 by screening pharmacologically active and click-chemistry compound libraries.

    Science.gov (United States)

    Minond, Dmitriy; Saldanha, S Adrian; Subramaniam, Prem; Spaargaren, Michael; Spicer, Timothy; Fotsing, Joseph R; Weide, Timo; Fokin, Valery V; Sharpless, K Barry; Galleni, Moreno; Bebrone, Carine; Lassaux, Patricia; Hodder, Peter

    2009-07-15

    VIM-2 is an Ambler class B metallo-beta-lactamase (MBL) capable of hydrolyzing a broad-spectrum of beta-lactam antibiotics. Although the discovery and development of MBL inhibitors continue to be an area of active research, an array of potent, small molecule inhibitors is yet to be fully characterized for VIM-2. In the presented research, a compound library screening approach was used to identify and characterize VIM-2 inhibitors from a library of pharmacologically active compounds as well as a focused 'click' chemistry library. The four most potent VIM-2 inhibitors resulting from a VIM-2 screen were characterized by kinetic studies in order to determine K(i) and mechanism of enzyme inhibition. As a result, two previously described pharmacologic agents, mitoxantrone (1,4-dihydroxy-5,8-bis([2-([2-hydroxyethyl]amino)ethyl]amino)-9,10-anthracenedione) and 4-chloromercuribenzoic acid (pCMB) were found to be active, the former as a non-competitive inhibitor (K(i)=K(i)(')=1.5+/-0.2microM) and the latter as a slowly reversible or irreversible inhibitor. Additionally, two novel sulfonyl-triazole analogs from the click library were identified as potent, competitive VIM-2 inhibitors: N-((4-((but-3-ynyloxy)methyl)-1H-1,2,3-triazol-5-yl)methyl)-4-iodobenzenesulfonamide (1, K(i)=0.41+/-0.03microM) and 4-iodo-N-((4-(methoxymethyl)-1H-1,2,3-triazol-5-yl)methyl)benzenesulfonamide (2, K(i)=1.4+/-0.10microM). Mitoxantrone and pCMB were also found to potentiate imipenem efficacy in MIC and synergy assays employing Escherichia coli. Taken together, all four compounds represent useful chemical probes to further investigate mechanisms of VIM-2 inhibition in biochemical and microbiology-based assays.

  9. Multistep continuous-flow synthesis in medicinal chemistry: discovery and preliminary structure-activity relationships of CCR8 ligands.

    Science.gov (United States)

    Petersen, Trine P; Mirsharghi, Sahar; Rummel, Pia C; Thiele, Stefanie; Rosenkilde, Mette M; Ritzén, Andreas; Ulven, Trond

    2013-07-08

    A three-step continuous-flow synthesis system and its application to the assembly of a new series of chemokine receptor ligands directly from commercial building blocks is reported. No scavenger columns or solvent switches are necessary to recover the desired test compounds, which were obtained in overall yields of 49-94%. The system is modular and flexible, and the individual steps of the sequence can be interchanged with similar outcome, extending the scope of the chemistry. Biological evaluation confirmed activity on the chemokine CCR8 receptor and provided initial structure-activity-relationship (SAR) information for this new ligand series, with the most potent member displaying full agonist activity with single-digit nanomolar potency. To the best of our knowledge, this represents the first published example of efficient use of multistep flow synthesis combined with biological testing and SAR studies in medicinal chemistry.

  10. Searching for halo-alkalophilic proteases maintaining stability and activity in hydrophilic aprotic solvents as biocatalysts in carbohydrate chemistry

    DEFF Research Database (Denmark)

    Pedersen, Lars Haastrup; Mørkholt, Camilla Kær; Nielsen, Carsten Bue

    2012-01-01

    BIOCAT2012, Hamburg University of Technology Book of Abstracts, p70 ISBN 987-3-941492 L12) Searching for halo-alkalophilic proteases maintaining stability and activity in hydrophilic aprotic solvents as biocatalysts in carbohydrate chemistry. Lars Haastrup Pedersen, Camilla Kær Mørkholt, Carsten...... Bue Nielsen Department of Biotechnology, Chemistry and Environmental Engineering Aalborg University Denmark Halo-alkalophilic proteases have proven relatively stable maintaining activity in hydrophilic aprotic solvents sufficiently to be useful as biocatalysts for regiospecific acylation of sucrose...... and other carbohydrates (1, 2). Therefore, we are searching for new bacterial halo-alkaline proteases from extreme environments in Denmark. So far we have identified a number of interesting isolates showing proteolytic activity at pH 7 and 10. Whole genome Illumina Hiseq 2000 amplicon sequencing, de novo...

  11. Non-enzymatic chemistry enables 2-hydroxyglutarate-mediated activation of 2-oxoglutarate oxygenases

    Science.gov (United States)

    Tarhonskaya, Hanna; Rydzik, Anna M.; Leung, Ivanhoe K. H.; Loik, Nikita D.; Chan, Mun Chiang; Kawamura, Akane; McCullagh, James S. O.; Claridge, Timothy D. W.; Flashman, Emily; Schofield, Christopher J.

    2014-01-01

    Accumulation of (R)-2-hydroxyglutarate in cells results from mutations to isocitrate dehydrogenase that correlate with cancer. A recent study reports that (R)-, but not (S)-2-hydroxyglutarate, acts as a co-substrate for the hypoxia-inducible factor prolyl hydroxylases via enzyme-catalysed oxidation to 2-oxoglutarate. Here we investigate the mechanism of 2-hydroxyglutarate-enabled activation of 2-oxoglutarate oxygenases, including prolyl hydroxylase domain 2, the most important human prolyl hydroxylase isoform. We observe that 2-hydroxyglutarate-enabled catalysis by prolyl hydroxylase domain 2 is not enantiomer-specific and is stimulated by ferrous/ferric ion and reducing agents including L-ascorbate. The results reveal that 2-hydroxyglutarate is oxidized to 2-oxoglutarate non-enzymatically, likely via iron-mediated Fenton-chemistry, at levels supporting in vitro catalysis by 2-oxoglutarate oxygenases. Succinic semialdehyde and succinate are also identified as products of 2-hydroxyglutarate oxidation. Overall, the results rationalize the reported effects of 2-hydroxyglutarate on catalysis by prolyl hydroxylases in vitro and suggest that non-enzymatic 2-hydroxyglutarate oxidation may be of biological interest. PMID:24594748

  12. Mentha suaveolens Ehrh. (Lamiaceae Essential Oil and Its Main Constituent Piperitenone Oxide: Biological Activities and Chemistry

    Directory of Open Access Journals (Sweden)

    Mijat Božović

    2015-05-01

    Full Text Available Since herbal medicines play an important role in the treatment of a wide range of diseases, there is a growing need for their quality control and standardization. Mentha suaveolens Ehrh. (MS is an aromatic herb with fruit and a spearmint flavor, used in the Mediterranean areas as a traditional medicine. It has an extensive range of biological activities, including cytotoxic, antimicrobial, antioxidant, anti-inflammatory, hypotensive and insecticidal properties, among others. This study aims to review the scientific findings and research reported to date on MS that prove many of the remarkable various biological actions, effects and some uses of this species as a source of bioactive natural compounds. On the other hand, piperitenone oxide (PO, the major chemical constituent of the carvone pathway MS essential oil, has been reported to exhibit numerous bioactivities in cells and animals. Thus, this integrated overview also surveys and interprets the present knowledge of chemistry and analysis of this oxygenated monoterpene, as well as its beneficial bioactivities. Areas for future research are suggested.

  13. Active Upper-atmosphere Chemistry and Dynamics from Polar Circulation Reversal on Titan

    Science.gov (United States)

    Teanby, Nicholas A.; Irwin, Patrick Gerard Joseph; Nixon, Conor A.; DeKok, Remco; Vinatier, Sandrine; Coustenis, Athena; Sefton-Nash, Elliot; Calcutt, Simon B.; Flasar, Michael F.

    2012-01-01

    Saturn's moon Titan has a nitrogen atmosphere comparable to Earth's, with a surface pressure of 1.4 bar. Numerical models reproduce the tropospheric conditions very well but have trouble explaining the observed middle-atmosphere temperatures, composition and winds. The top of the middle-atmosphere circulation has been thought to lie at an altitude of 450 to 500 kilometres, where there is a layer of haze that appears to be separated from the main haze deck. This 'detached' haze was previously explained as being due to the colocation of peak haze production and the limit of dynamical transport by the circulation's upper branch. Herewe report a build-up of trace gases over the south pole approximately two years after observing the 2009 post-equinox circulation reversal, from which we conclude that middle-atmosphere circulation must extend to an altitude of at least 600 kilometres. The primary drivers of this circulation are summer-hemisphere heating of haze by absorption of solar radiation and winter-hemisphere cooling due to infrared emission by haze and trace gases; our results therefore imply that these effects are important well into the thermosphere (altitudes higher than 500 kilometres). This requires both active upper-atmosphere chemistry, consistent with the detection of high-complexity molecules and ions at altitudes greater than 950 kilometres, and an alternative explanation for the detached haze, such as a transition in haze particle growth from monomers to fractal structures.

  14. Fluorometric method for inorganic pyrophosphatase activity detection and inhibitor screening based on click chemistry.

    Science.gov (United States)

    Xu, Kefeng; Chen, Zhonghui; Zhou, Ling; Zheng, Ou; Wu, Xiaoping; Guo, Longhua; Qiu, Bin; Lin, Zhenyu; Chen, Guonan

    2015-01-06

    A fluorometric method for pyrophosphatase (PPase) activity detection was developed based on click chemistry. Cu(II) can coordinate with pyrophosphate (PPi), the addition of pyrophosphatase (PPase) into the above system can destroy the coordinate compound because PPase catalyzes the hydrolysis of PPi into inorganic phosphate and produces free Cu(II), and free Cu(II) can be reduced by sodium ascorbate (SA) to form Cu(I), which in turn initiates the ligating reaction between nonfluorescent 3-azidocoumarins and terminal alkynes to produce a highly fluorescent triazole complex, based on which, a simple and sensitive turn on fluorometric method for PPase can be developed. The fluorescence intensity of the system has a linear relationship with the logarithm of the PPase concentration in the range of 0.5 and 10 mU with a detection limit down to 0.2 mU (S/N = 3). This method is cost-effective and convenient without any labels or complicated operations. The proposed system was applied to screen the potential PPase inhibitor with high efficiency. The proposed method can be applied to diagnosis of PPase-related diseases.

  15. Influence of cigarette circumference on smoke chemistry, biological activity, and smoking behaviour.

    Science.gov (United States)

    McAdam, Kevin; Eldridge, Alison; Fearon, Ian M; Liu, Chuan; Manson, Andrew; Murphy, James; Porter, Andrew

    2016-12-01

    Cigarettes with reduced circumference are increasingly popular in some countries, hence it is important to understand the effects of circumference reduction on their burning behaviour, smoke chemistry and bioactivity. Reducing circumference reduces tobacco mass burn rate, puff count and static burn time, and increases draw resistance and rod length burned during puff and smoulder periods. Smoulder temperature increases with decreasing circumference, but with no discernible effect on cigarette ignition propensity during a standard test. At constant packing density, mainstream (MS) and sidestream (SS) tar and nicotine yields decrease approximately linearly with decreasing circumference, as do the majority of smoke toxicants. However, volatile aldehydes, particularly formaldehyde, show a distinctly non-linear relationship with circumference and increases in the ratios of aldehydes to tar and nicotine have been observed as the circumference decreases. Mutagenic, cytotoxic and tumorigenic specific activities of smoke condensates (i.e. per unit weight of condensate) decrease as circumference decreases. Recent studies suggest that there is no statistical difference in mouth-level exposure to tar and nicotine among smokers of cigarettes with different circumferences. Commercially available slim cigarettes usually have changes in other cigarette design features compared with cigarettes with standard circumference, so it is difficult to isolate the effect of circumference on the properties of commercial products. However, available data shows that changes in cigarette circumference offer no discernible change to the harm associated with smoking. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  16. Mentha suaveolens Ehrh. (Lamiaceae) Essential Oil and Its Main Constituent Piperitenone Oxide: Biological Activities and Chemistry.

    Science.gov (United States)

    Božović, Mijat; Pirolli, Adele; Ragno, Rino

    2015-05-13

    Since herbal medicines play an important role in the treatment of a wide range of diseases, there is a growing need for their quality control and standardization. Mentha suaveolens Ehrh. (MS) is an aromatic herb with fruit and a spearmint flavor, used in the Mediterranean areas as a traditional medicine. It has an extensive range of biological activities, including cytotoxic, antimicrobial, antioxidant, anti-inflammatory, hypotensive and insecticidal properties, among others. This study aims to review the scientific findings and research reported to date on MS that prove many of the remarkable various biological actions, effects and some uses of this species as a source of bioactive natural compounds. On the other hand, piperitenone oxide (PO), the major chemical constituent of the carvone pathway MS essential oil, has been reported to exhibit numerous bioactivities in cells and animals. Thus, this integrated overview also surveys and interprets the present knowledge of chemistry and analysis of this oxygenated monoterpene, as well as its beneficial bioactivities. Areas for future research are suggested.

  17. Coordination chemistry and biological activity of 5'-OH modified quinoline-B12 derivatives.

    Science.gov (United States)

    Zelenka, Karel; Brandl, Helmut; Spingler, Bernhard; Zelder, Felix

    2011-10-14

    The consequences of structural modifications at the 5'-OH ribofuranotide moiety of quinoline modified B12 derivatives are discussed in regard of the coordination chemistry, the electrochemical properties and the biological behaviour of the compound.

  18. Identification of the biologically active liquid chemistry induced by a nonthermal atmospheric pressure plasma jet.

    Science.gov (United States)

    Wende, Kristian; Williams, Paul; Dalluge, Joe; Gaens, Wouter Van; Aboubakr, Hamada; Bischof, John; von Woedtke, Thomas; Goyal, Sagar M; Weltmann, Klaus-Dieter; Bogaerts, Annemie; Masur, Kai; Bruggeman, Peter J

    2015-06-06

    The mechanism of interaction of cold nonequilibrium plasma jets with mammalian cells in physiologic liquid is reported. The major biological active species produced by an argon RF plasma jet responsible for cell viability reduction are analyzed by experimental results obtained through physical, biological, and chemical diagnostics. This is complemented with chemical kinetics modeling of the plasma source to assess the dominant reactive gas phase species. Different plasma chemistries are obtained by changing the feed gas composition of the cold argon based RF plasma jet from argon, humidified argon (0.27%), to argon/oxygen (1%) and argon/air (1%) at constant power. A minimal consensus physiologic liquid was used, providing isotonic and isohydric conditions and nutrients but is devoid of scavengers or serum constituents. While argon and humidified argon plasma led to the creation of hydrogen peroxide dominated action on the mammalian cells, argon-oxygen and argon-air plasma created a very different biological action and was characterized by trace amounts of hydrogen peroxide only. In particular, for the argon-oxygen (1%), the authors observed a strong negative effect on mammalian cell proliferation and metabolism. This effect was distance dependent and showed a half life time of 30 min in a scavenger free physiologic buffer. Neither catalase and mannitol nor superoxide dismutase could rescue the cell proliferation rate. The strong distance dependency of the effect as well as the low water solubility rules out a major role for ozone and singlet oxygen but suggests a dominant role of atomic oxygen. Experimental results suggest that O reacts with chloride, yielding Cl2(-) or ClO(-). These chlorine species have a limited lifetime under physiologic conditions and therefore show a strong time dependent biological activity. The outcomes are compared with an argon MHz plasma jet (kinpen) to assess the differences between these (at least seemingly) similar plasma sources.

  19. "Green chemistry": os 12 princípios da química verde e sua inserção nas atividades de ensino e pesquisa Green chemistry: the 12 principles of green chemistry and it insertion in the teach and research activities

    Directory of Open Access Journals (Sweden)

    Eder João Lenardão

    2003-01-01

    Full Text Available Green chemistry ¾ defined as the design, development, and application of chemical processes and products to reduce or eliminate the use and generation of substances hazardous to human health and the environment. This article summarizes the 12 principles of green chemistry, describing how they have been applied to the academic, industrial and research activities around the world.

  20. Activity theory as a tool to address the problem of chemistry's lack of relevance in secondary school chemical education

    Science.gov (United States)

    van Aalsvoort, Joke

    In a previous article, the problem of chemistry's lack of relevance in secondary chemical education was analysed using logical positivism as a tool. This article starts with the hypothesis that the problem can be addressed by means of activity theory, one of the important theories within the sociocultural school. The reason for this expectation is that, while logical positivism creates a divide between science and society, activity theory offers a model of society in which science and society are related. With the use of this model, a new course for grade nine has been constructed. This results in a confirmation of the hypothesis, at least at a theoretical level. A comparison with the Salters' approach is made in order to demonstrate the relative merits of a mediated way of dealing with the problem of the lack of relevance of chemistry in chemical education.

  1. The Construction of Metal-Organic Framework with Active Backbones by the Utilization of Reticular Chemistry

    Science.gov (United States)

    Choi, Eunwoo

    With the principles of reticular chemistry, metal-organic frameworks with ultra-high porosity, chiral-recognition unit as a chiral stationary phase, metalloporhyrins for enhanced hydrogen adsorption and an intrinsic conductivity to form porous conductors, have been prepared. This dissertation presents how the principles of reticular chemistry were utilized to achieve in the preparations of metal-organic frameworks with a large surface area and active backbones. Through the simple isoreticular (having the same framework topology) expansion from MOF-177 composed with 1,3,5-tris(4'-carboxyphenyl-)benzene (BTB3-) as the strut; MOF-200 was prepared with 4,4',4"-(benzene-1,3,5-triyl-tris(benzene-4,1-diy1))tribenzoic acid an extension from BTB3- by a phenylene unit to yield one of the most porous MOFs with a Langmuir surface area of 10,400 m2. and the lowest density of 0.22 cm3.g-1. A successful thermal polymerization reaction at 325 °C inside of the pores of highly porous MOF, MOF-177, was performed and verified the integrity of the MOF structure even after the thermal reaction. 1,4-Diphenylbutadiyne that is known to polymerize upon heating to form a conjugated backbone was impregnated via solution-diffusion into MOF-177 and then subsequently polymerized by heat to form polymer impregnated MOF-177. Characterization was carried out using powder X-ray diffraction and volumetric sorption analyzer. MOF-1020 with a linear quaterphenyl dicarboxylate-based strut was designed to contain a chiral bisbinaphthyl crown-ether moiety for alkyl ammonium resolution was precisely placed into a Zn4O(CO2)6-based cubic MOF structure. Unfortunately, the chiral resolution was not achieved due to the sensitivity and the pore environment of MOF-1020. However, an interesting phenomenon was observed, where the loss of crystallinity occurs upon solvent removal while the crystallites remain shiny and crystalline, but it readily is restored upon re-solvation of the crystallites. This rare

  2. Ciprofloxacin adsorption on graphene and granular activated carbon: kinetics, isotherms, and effects of solution chemistry.

    Science.gov (United States)

    Zhu, Xuan; Tsang, Daniel C W; Chen, Feng; Li, Shiyu; Yang, Xin

    2015-01-01

    Ciprofloxacin (CIP) is a commonly used antibiotic and widely detected in wastewaters and farmlands nowadays. This study evaluated the efficacy of next-generation adsorbent (graphene) and conventional adsorbent (granular activated carbon, GAC) for CIP removal. Batch experiments and characterization tests were conducted to investigate the adsorption kinetics, equilibrium isotherms, thermodynamic properties, and the influences of solution chemistry (pH, ionic strength, natural organic matter (NOM), and water sources). Compared to GAC, graphene showed significantly faster adsorption and reached equilibrium within 3 min, confirming the rapid access of CIP into the macroporous network of high surface area of graphene as revealed by the Brunner-Emmet-Teller measurements analysis. The kinetics was better described by a pseudo-second-order model, suggesting the importance of the initial CIP concentration related to surface site availability of graphene. The adsorption isotherm on graphene followed Langmuir model with a maximum adsorption capacity of 323 mg/g, which was higher than other reported carbonaceous adsorbents. The CIP adsorption was thermodynamically favourable on graphene and primarily occurred through π - π interaction, according to the FTIR spectroscopy. While the adsorption capacity of graphene decreased with increasing solution pH due to the speciation change of CIP, the adverse effects of ionic strength (0.01-0.5 mol L(-1)), presence of NOM (5 mg L⁻¹), and different water sources (river water or drinking water) were less significant on graphene than GAC. These results indicated that graphene can serve as an alternative adsorbent for CIP removal in commonly encountered field conditions, if proper separation and recovery is available in place.

  3. Plants, Pollution and Public Engagement with Atmospheric Chemistry: Sharing the TEMPO Story Through Ozone Garden Activities

    Science.gov (United States)

    Reilly, L. G.; Pippin, M. R.; Malick, E.; Summers, D.; Dussault, M. E.; Wright, E. A.; Skelly, J.

    2016-12-01

    What do a snap-bean plant and a future NASA satellite instrument named TEMPO have in common? They are both indicators of the quality of the air we breathe. Scientists, educators, and museum and student collaborators of the Tropospheric Emissions: Monitoring Pollution (TEMPO) instrument team are developing a program model to engage learners of all ages via public ozone garden exhibits and associated activities. TEMPO, an ultraviolet and visible spectroscopy instrument due for launch on a geostationary host satellite between 2019 and 2021, will scan North America hourly to measure the major elements in the tropospheric ozone chemistry cycle, providing near real-time data with high temporal and spatial resolution. The TEMPO mission provides a unique opportunity to share the story of the effects of air quality on living organisms. A public ozone garden exhibit affords an accessible way to understand atmospheric science through a connection with nature, while providing a visual representation of the impact of ozone pollution on living organisms. A prototype ozone garden exhibit was established at the Virginia Living Museum in partnership with NASA Langley, and has served as a site to formatively evaluate garden planting and exhibit display protocols, hands-on interpretive activities, and citizen science data collection protocols for learners as young as 3 to 10 as well as older adults. The fun and engaging activities, optimized for adult-child interaction in informal or free-choice learning environments, are aimed at developing foundational science skills such as observing, comparing, classifying, and collecting and making sense of data in the context of thinking about air quality - all NGSS-emphasized scientific practices, as well as key capabilities for future contributing members of the citizen science community. As the launch of TEMPO approaches, a major public engagement effort will include disseminating this ozone garden exhibit and program model to a network of

  4. Organization of a cognitive activity of students when teaching analytical chemistry

    Directory of Open Access Journals (Sweden)

    А. Tapalova

    2012-12-01

    Full Text Available Qualitative analysis allows using basic knowledge of general and inorganic chemistry for the solution of practical problems, disclosure the chemism of the processes that are fundamental for  the methods of analysis. Systematic qualitative analysis develops analytical thinking, establishes a scientific style of thinking of students.Сhemical analysis requires certain skills and abilities and develops the general chemical culture of the future teachers оn chemistry. The result can be evaluated in the course of self-control, peer review, and solving creative problems. Mastering the techniques of critical thinking (comparison, abstraction, generalization and their use in a particular chemical material - are necessary element in the formation of professional thinking of the future chemistry teacher.

  5. The application of click chemistry in the synthesis of agents with anticancer activity

    OpenAIRE

    Ma N; Wang Y.; Zhao BX; Ye WC; Jiang S

    2015-01-01

    Nan Ma,1–3 Ying Wang,3 Bing-Xin Zhao,3 Wen-Cai Ye,1,3 Sheng Jiang2 1Department of Natural Medicinal Chemistry, China Pharmaceutical University, Nanjing, 2Laboratory of Medicinal Chemistry, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, 3Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, People’s Republic of China Abstract: The copper(I)-catalyzed 1,3-dipolar cycl...

  6. Infrared and Raman Spectroscopy: A Discovery-Based Activity for the General Chemistry Curriculum

    Science.gov (United States)

    Borgsmiller, Karen L.; O'Connell, Dylan J.; Klauenberg, Kathryn M.; Wilson, Peter M.; Stromberg, Christopher J.

    2012-01-01

    A discovery-based method is described for incorporating the concepts of IR and Raman spectroscopy into the general chemistry curriculum. Students use three sets of springs to model the properties of single, double, and triple covalent bonds. Then, Gaussian 03W molecular modeling software is used to illustrate the relationship between bond…

  7. Island Explorations: Discovering Effects of Environmental Research-Based Lab Activities on Analytical Chemistry Students

    Science.gov (United States)

    Tomasik, Janice Hall; LeCaptain, Dale; Murphy, Sarah; Martin, Mary; Knight, Rachel M.; Harke, Maureen A.; Burke, Ryan; Beck, Kara; Acevedo-Polakovich, I. David

    2014-01-01

    Motivating students in analytical chemistry can be challenging, in part because of the complexity and breadth of topics involved. Some methods that help encourage students and convey real-world relevancy of the material include incorporating environmental issues, research-based lab experiments, and service learning projects. In this paper, we…

  8. Development and Use of Online Prelaboratory Activities in Organic Chemistry to Improve Students' Laboratory Experience

    Science.gov (United States)

    Chaytor, Jennifer L.; Al Mughalaq, Mohammad; Butler, Hailee

    2017-01-01

    Online prelaboratory videos and quizzes were prepared for all experiments in CHEM 231, Organic Chemistry I Laboratory. It was anticipated that watching the videos would help students be better prepared for the laboratory, decrease their anxiety surrounding the laboratory, and increase their understanding of the theories and concepts presented.…

  9. "JCE" Classroom Activity #110: Artistic Anthocyanins and Acid-Base Chemistry

    Science.gov (United States)

    Lech, Jenna; Dounin, Vladimir

    2011-01-01

    Art and science are sometimes viewed as opposing subjects, but are united in many ways. With an increased awareness of the benefits of interdisciplinary studies in education, it is desirable to show students how different subjects impact one another. Visual arts are greatly connected to chemistry in several ways. Pigments are usually synthetically…

  10. "JCE" Classroom Activity #110: Artistic Anthocyanins and Acid-Base Chemistry

    Science.gov (United States)

    Lech, Jenna; Dounin, Vladimir

    2011-01-01

    Art and science are sometimes viewed as opposing subjects, but are united in many ways. With an increased awareness of the benefits of interdisciplinary studies in education, it is desirable to show students how different subjects impact one another. Visual arts are greatly connected to chemistry in several ways. Pigments are usually synthetically…

  11. Island Explorations: Discovering Effects of Environmental Research-Based Lab Activities on Analytical Chemistry Students

    Science.gov (United States)

    Tomasik, Janice Hall; LeCaptain, Dale; Murphy, Sarah; Martin, Mary; Knight, Rachel M.; Harke, Maureen A.; Burke, Ryan; Beck, Kara; Acevedo-Polakovich, I. David

    2014-01-01

    Motivating students in analytical chemistry can be challenging, in part because of the complexity and breadth of topics involved. Some methods that help encourage students and convey real-world relevancy of the material include incorporating environmental issues, research-based lab experiments, and service learning projects. In this paper, we…

  12. Infrared and Raman Spectroscopy: A Discovery-Based Activity for the General Chemistry Curriculum

    Science.gov (United States)

    Borgsmiller, Karen L.; O'Connell, Dylan J.; Klauenberg, Kathryn M.; Wilson, Peter M.; Stromberg, Christopher J.

    2012-01-01

    A discovery-based method is described for incorporating the concepts of IR and Raman spectroscopy into the general chemistry curriculum. Students use three sets of springs to model the properties of single, double, and triple covalent bonds. Then, Gaussian 03W molecular modeling software is used to illustrate the relationship between bond…

  13. Activity and property landscape modeling is at the interface of chemoinformatics and medicinal chemistry.

    Science.gov (United States)

    Medina-Franco, José L; Navarrete-Vázquez, Gabriel; Méndez-Lucio, Oscar

    2015-01-01

    Property landscape modeling (PLM) methods are at the interface of experimental sciences and computational chemistry. PLM are becoming a common strategy to describe systematically structure-property relationships of datasets. Thus far, PLM have been used mainly in medicinal chemistry and drug discovery. Herein, we survey advances on key topics on PLM with emphasis on questions often raised regarding the outcomes of the property landscape studies. We also emphasize on concepts of PLM that are being extended to other experimental areas beyond drug discovery. Topics discussed in this paper include applications of PLM to further characterize protein-ligand interactions, the utility of PLM as a quantitative and descriptive approach, and the statistical validation of property cliffs.

  14. The Importance of Computer Based Active Learning for Basic Chemistry in Vocational High Schools

    OpenAIRE

    Tuğçe GÜNTER; Ebru OFLUOĞLU DEMİR; AKYOL GÜNER, TÜRKAN

    2011-01-01

    Chemistry is a very comprehensive discipline that researches atoms; molecules; the structure of matter in the form of element or compound; combinations, and physical and chemical properties of matter; macroscopic and microscopic transformations of matters; the energy and entropy released or absorbed in the course of these transformations; the structures and functions of carbohydrates, lipids, proteins, enzymes, vitamins and minerals in the body. This discipline includes numerous reactions at ...

  15. Liaison activities with the Institute of Physical Chemistry/Russian Academy of Science Fiscal Year 1995

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, C.H.

    1995-09-01

    Investigations into the chemistry of alkaline Hanford Site tank waste (TTP RL4-3-20-04) were conducted in Fiscal Year 1995 at Westinghouse Hanford Company under the support of the Efficient Separations and Processing Crosscutting Program (EM-53). The investigation had two main subtasks: liaison with the Institute of Physical Chemistry of the Russian Academy of Science and further laboratory testing of the chemistry of thermal reconstitution of Hanford Site tank waste. Progress, which was achieved in the liaison subtask during Fiscal Year 1995, is summarized as follows: (1) A technical dialogue has been established with Institute scientists. (2) Editing was done on a technical literature review on the chemistry of transuranic elements and technetium in alkaline media written by researchers at the Institute. The report was issued in May 1995 as a Westinghouse Hanford Company document. (3) Four tasks from the Institute were selected for support by the U.S. Department of Energy. Work on three tasks commenced on 1 March 1995; the fourth task commenced on 1 April 1995. (4) Technical information describing the composition of Hanford Site tank waste was supplied to the Institute. (5) A program review of the four tasks was conducted at the Institute during a visit 25 August to 1 September, 1995. A lecture on the origin, composition, and proposed treatment of Hanford Site tank wastes was presented during this visit. Eight additional tasks were proposed by Institute scientists for support in Fiscal Year 1996. (6) A paper was presented at the Fifth International Conference on Radioactive Waste Management and Environmental Remediation (ICEM`95) in Berlin, Germany on 3 to 9 September, 1995 on the solubility of actinides in alkaline media.

  16. Diversity-Oriented Synthesis of a Library of Substituted Tetrahydropyrones Using Oxidative Carbon-Hydrogen Bond Activation and Click Chemistry

    Directory of Open Access Journals (Sweden)

    Paul E. Floreancig

    2011-05-01

    Full Text Available Eighteen (2RS,6RS-2-(4-methoxyphenyl-6-(substituted ethyldihydro-2H-pyran-4(3Hones were synthesized via a DDQ-mediated oxidative carbon-hydrogen bond activation reaction. Fourteen of these tetrahydropyrans were substituted with triazoles readily assembled via azide-alkyne click-chemistry reactions. Examples of a linked benzotriazole and pyrazole motif were also prepared. To complement the structural diversity, the alcohol substrates were obtained from stereoselective reductions of the tetrahydropyrone. This library provides rapid access to structurally diverse non-natural compounds to be screened against a variety of biological targets.

  17. The design of a bipodal bis(pentafluorophenoxy)aluminate supported on silica as an activator for ethylene polymerization using surface organometallic chemistry.

    Science.gov (United States)

    Sauter, Dominique W; Popoff, Nicolas; Bashir, Muhammad Ahsan; Szeto, Kai C; Gauvin, Régis M; Delevoye, Laurent; Taoufik, Mostafa; Boisson, Christophe

    2016-04-04

    A new class of well-defined activating supports for olefin polymerization was obtained via the surface organometallic chemistry approach. High activities in slurry polymerization of ethylene along with industrial-grade physical properties of the resulting polyethylene were obtained when these activators were combined with metallocene complexes in the presence of triisobutylaluminium.

  18. Bimolecular reactions of activated species: An analysis of problematic HC(O)C(O) chemistry

    Science.gov (United States)

    Shannon, Robin J.; Robertson, Struan H.; Blitz, Mark A.; Seakins, Paul W.

    2016-09-01

    Experimental studies have demonstrated the importance of non-thermal bimolecular association chemistry. Recently a fully reversible method for incorporating any number of such non-thermal reactions into a single master equation has been developed (Green and Robertson, 2014) [10]. Using this methodology experimental results for the system: (1) (CHO)2 + OH → HC(O)C(O) + H2O, (2) HC(O)C(O) → HCO + CO, (3) HC(O)C(O) + O2 → OH + CO + CO2, are modeled, reproducing the temperature and pressure dependence of the OH yield. An issue remains as to how to model energy partition into HC(O)C(O).

  19. Synthesis of amphiphilic aminated inulin via 'click chemistry' and evaluation for its antibacterial activity.

    Science.gov (United States)

    Dong, Fang; Zhang, Jun; Yu, Chunwei; Li, Qing; Ren, Jianming; Wang, Gang; Gu, Guodong; Guo, Zhanyong

    2014-09-15

    Inulins are a group of abundant, water-soluble, renewable polysaccharides, which exhibit attractive bioactivities and natural properties. Improvement such as chemical modification of inulin is often performed prior to further utilization. We hereby presented a method to modify inulin at its primary hydroxyls to synthesize amphiphilic aminated inulin via 'click chemistry' to facilitate its chemical manipulation. Additionally, its antibacterial property against Staphylococcus aureus (S. aureus) was also evaluated and the best inhibitory index against S. aureus was 58% at 1mg/mL. As the amphiphilic aminated inulin is easy to prepare and exhibits improved bioactivity, this material may represent as an attractive new platform for chemical modifications of inulin.

  20. Liaison activities with the institute of physical chemistry, Russian academy of sciences: FY 1996

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, C.H.

    1996-09-23

    The task ``IPC/RAS Liaison and Tank Waste Testing`` is a program being conducted in fiscal year (FY) 1996 with the support of the U.S. Department of Energy (DOE) Office of Science and Technology, EM-53 Efficient Separations and Processing (ESP) Crosscutting Program, under the technical task plan RLA6C342. The principal investigator is Cal Delegard of the Westinghouse Hanford Company. The task involves a technical liaison with the Institute of Physical Chemistry of the Russian Academy of Sciences (IPC/RAS) and their DOE-supported investigations into the fundamental and applied chemistry of the transuranium elements (primarily neptunium, plutonium, and americium) and technetium in alkaline media. The task has three purposes: 1. Providing technical information and technical direction to the IPC/RAS. 2. Disseminating IPC/RAS data and information to the DOE technical community. 3. Verifying IPC/RAS results through laboratory testing and comparison with published data. This report fulfills the milestone ``Provide End-of-Year Report to Focus Area,`` due September 30, 1996.

  1. Litter chemistry prevails over litter consumers in mediating effects of past steel industry activities on leaf litter decomposition.

    Science.gov (United States)

    Lucisine, Pierre; Lecerf, Antoine; Danger, Michaël; Felten, Vincent; Aran, Delphine; Auclerc, Apolline; Gross, Elisabeth M; Huot, Hermine; Morel, Jean-Louis; Muller, Serge; Nahmani, Johanne; Maunoury-Danger, Florence

    2015-12-15

    Soil pollution has adverse effects on the performance and life history traits of microorganisms, plants, and animals, yet evidence indicates that even the most polluted sites can support structurally-complex and dynamic ecosystems. The present study aims at determining whether and how litter decomposition, one of the most important soil ecological processes leaf, is affected in a highly trace-metal polluted site. We postulated that past steel mill activities resulting in soil pollution and associated changes in soil characteristics would influence the rate of litter decomposition through two non-exclusive pathways: altered litter chemistry and responses of decomposers to lethal and sub-lethal toxic stress. We carried out a litter-bag experiment using Populus tremula L. leaf litter collected at, and allowed to decompose in, a trace metal polluted site and in three unpolluted sites used as controls. We designed a fully-factorial transplant experimental design to assess effects of litter origin and exposure site on the rate of litter decomposition. We further determined initial litter chemistry, fungal biomass, mesofauna abundance in litter bags, and the soil macrofauna community. Irrespective of the site of litter exposure, litter originating from the polluted site had a two-fold faster decomposition than litter from the unpolluted sites. Litter chemistry, notably the lignin content, seemed most important in explaining the degradation rate of the leaf litter. Abundance of meso and macro-detritivores was higher at the polluted site than at the unpolluted sites. However, litter decomposition proceeded at similar rates in polluted and unpolluted sites. Our results show that trace metal pollution and associated soil and litter changes do not necessarily weaken consumer control on litter decomposition through lethal and sub-lethal toxic stress.

  2. Project-focused activity and knowledge tracker: a unified data analysis, collaboration, and workflow tool for medicinal chemistry project teams.

    Science.gov (United States)

    Brodney, Marian D; Brosius, Arthur D; Gregory, Tracy; Heck, Steven D; Klug-McLeod, Jacquelyn L; Poss, Christopher S

    2009-12-01

    Advances in the field of drug discovery have brought an explosion in the quantity of data available to medicinal chemists and other project team members. New strategies and systems are needed to help these scientists to efficiently gather, organize, analyze, annotate, and share data about potential new drug molecules of interest to their project teams. Herein we describe a suite of integrated services and end-user applications that facilitate these activities throughout the medicinal chemistry design cycle. The Automated Data Presentation (ADP) and Virtual Compound Profiler (VCP) processes automate the gathering, organization, and storage of real and virtual molecules, respectively, and associated data. The Project-Focused Activity and Knowledge Tracker (PFAKT) provides a unified data analysis and collaboration environment, enhancing decision-making, improving team communication, and increasing efficiency.

  3. Well-Defined Molybdenum Oxo Alkyl Complex Supported on Silica by Surface Organometallic Chemistry: A Highly Active Olefin Metathesis Precatalyst.

    Science.gov (United States)

    Merle, Nicolas; Le Quéméner, Frédéric; Bouhoute, Yassine; Szeto, Kai C; De Mallmann, Aimery; Barman, Samir; Samantaray, Manoja K; Delevoye, Laurent; Gauvin, Régis M; Taoufik, Mostafa; Basset, Jean-Marie

    2017-02-15

    The well-defined silica-supported molybdenum oxo alkyl species (≡SiO-)MoO(CH2(t)Bu)3 was selectively prepared by grafting of MoO(CH2(t)Bu)3Cl onto partially dehydroxylated silica (silica700) using the surface organometallic chemistry approach. This surface species was fully characterized by elemental analysis and DRIFT, solid-state NMR, and EXAFS spectroscopy. This new material is related to the active species of industrial supported MoO3/SiO2 olefin metathesis catalysts. It displays very high activity in propene self-metathesis at mild (turnover number = 90 000 after 25 h). Remarkably, its catalytic performance outpaces those of the parent imido derivative and its tungsten oxo analogue.

  4. High Structure Active Learning Pedagogy for the Teaching of Organic Chemistry: Assessing the Impact on Academic Outcomes

    Science.gov (United States)

    Crimmins, Michael T.; Midkiff, Brooke

    2017-01-01

    Organic Chemistry is a required course for programs in chemistry, biology, and many health science careers. It has historically been considered a highly challenging course with significant failure rates. As with many science disciplines, the teaching of Organic Chemistry has traditionally focused on unstructured exposition-centered delivery of…

  5. Students' Perceptions of Teaching in Context-Based and Traditional Chemistry Classrooms: Comparing Content, Learning Activities, and Interpersonal Perspectives

    Science.gov (United States)

    Overman, Michelle; Vermunt, Jan D.; Meijer, Paulien C.; Bulte, Astrid M. W.; Brekelmans, Mieke

    2014-01-01

    Context-based curriculum reforms in chemistry education are thought to bring greater diversity to the ways in which chemistry teachers organize their teaching. First and foremost, students are expected to perceive this diversity. However, empirical research on how students perceive their teacher's teaching in context-based chemistry classrooms,…

  6. Surface chemistry of Au/TiO2: Thermally and photolytically activated reactions

    Science.gov (United States)

    Panayotov, Dimitar A.; Morris, John R.

    2016-03-01

    The fascinating particle size dependence to the physical, photophysical, and chemical properties of gold has motivated thousands of studies focused on exploring the ability of supported gold nanoparticles to catalyze chemical transformations. In particular, titanium dioxide-supported gold (Au/TiO2) nanoparticles may provide the right combination of electronic structure, structural dynamics, and stability to affect catalysis in important practical applications from environmental remediation to selective hydrogenation to carbon monoxide oxidation. Harnessing the full potential of Au/TiO2 will require a detailed atomic-scale understanding of the thermal and photolytic processes that accompany chemical conversion. This review describes some of the unique properties exhibited by particulate gold before delving into how those properties affect chemistry on titania supports. Particular attention is given first to thermally driven reactions on single crystal system. This review then addresses nanoparticulate samples in an effort begin to bridge the so-called materials gap. Building on the foundation provided by the large body of work in the field of thermal catalysis, the review describes new research into light-driven catalysis on Au/TiO2. Importantly, the reader should bear in mind throughout this review that thermal chemistry and thermal effects typically accompany photochemistry. Distinguishing between thermally-driven stages of a reaction and photo-induced steps remains a significant challenge, but one that experimentalists and theorists are beginning to decipher with new approaches. Finally, a summary of several state-of-the-art studies describes how they are illuminating new frontiers in the quest to exploit Au/TiO2 as an efficient catalyst and low-energy photocatalyst.

  7. Active and Widespread Halogen Chemistry in the Tropical and Subtropical Free Troposphere

    Science.gov (United States)

    Wang, Siyuan; Schmidt, Johan A.; Baidar, Sunil; Coburn, Sean; Dix, Barbara; Koenig, Theodore K.; Apel, Eric; Bowdalo, Dene; Campos, Teresa; Eloranta, Ed; Evans, Mathew J.; Digangi, Joshua P.; Zondlo, Mark A.; Gao, Ru-shan; Haggerty, Julie A.; Hall, Samuel R.; Hornbrook, Rebecca S.; Jacob, Daniel; Morley, Bruce; Pierce, Bradley; Reeves, Mike; Romashkin, Pavel; Ter Schure, Arnout; Volkamer, Rainer

    2015-01-01

    Halogens in the troposphere are increasingly recognized as playing an important role for atmospheric chemistry, and possibly climate. Bromine and iodine react catalytically to destroy ozone (O3), oxidize mercury, and modify oxidative capacity that is relevant for the lifetime of greenhouse gases. Most of the tropospheric O3 and methane (CH4) loss occurs at tropical latitudes. Here we report simultaneous measurements of vertical profiles of bromine oxide (BrO) and iodine oxide (IO) in the tropical and subtropical free troposphere (10degN to 40degS), and show that these halogens are responsible for 34% of the column-integrated loss of tropospheric O3. The observed BrO concentrations increase strongly with altitude (approx.3.4 pptv at 13.5 km), and are 2-4 times higher than predicted in the tropical free troposphere. BrO resembles model predictions more closely in stratospheric air. The largest model low bias is observed in the lower tropical transition layer (TTL) over the tropical eastern Pacific Ocean, and may reflect a missing inorganic bromine source supplying an additional 2.5-6.4 pptv total inorganic bromine (Bry), or model overestimated Bry wet scavenging. Our results highlight the importance of heterogeneous chemistry on ice clouds, and imply an additional Bry source from the debromination of sea salt residue in the lower TTL. The observed levels of bromine oxidize mercury up to 3.5 times faster than models predict, possibly increasing mercury deposition to the ocean. The halogen-catalyzed loss of tropospheric O3 needs to be considered when estimating past and future ozone radiative effects.

  8. Adsorption of a Textile Dye on Commercial Activated Carbon: A Simple Experiment to Explore the Role of Surface Chemistry and Ionic Strength

    Science.gov (United States)

    Martins, Angela; Nunes, Nelson

    2015-01-01

    In this study, an adsorption experiment is proposed using commercial activated carbon as adsorbent and a textile azo dye, Mordant Blue-9, as adsorbate. The surface chemistry of the activated carbon is changed through a simple oxidation treatment and the ionic strength of the dye solution is also modified, simulating distinct conditions of water…

  9. Reduction of (68)Ge activity containing liquid waste from (68)Ga PET chemistry in nuclear medicine and radiopharmacy by solidification.

    Science.gov (United States)

    de Blois, Erik; Chan, Ho Sze; Roy, Kamalika; Krenning, Eric P; Breeman, Wouter A P

    PET with (68)Ga from the TiO2- or SnO2- based (68)Ge/(68)Ga generators is of increasing interest for PET imaging in nuclear medicine. In general, radionuclidic purity ((68)Ge vs. (68)Ga activity) of the eluate of these generators varies between 0.01 and 0.001%. Liquid waste containing low amounts of (68)Ge activity is produced by eluting the (68)Ge/(68)Ga generators and residues from PET chemistry. Since clearance level of (68)Ge activity in waste may not exceed 10 Bq/g, as stated by European Directive 96/29/EURATOM, our purpose was to reduce (68)Ge activity in solution from >10 kBq/g to waste. Most efficient method to reduce the (68)Ge activity is by sorption of TiO2 or Fe2O3 and subsequent centrifugation. The required 10 Bq per mL level of (68)Ge activity in waste was reached by Fe2O3 logarithmically, whereas with TiO2 asymptotically. The procedure with Fe2O3 eliminates ≥90% of the (68)Ge activity per treatment. Eventually, to simplify the processing a recirculation system was used to investigate (68)Ge activity sorption on TiO2, Fe2O3 or Zeolite. Zeolite was introduced for its high sorption at low pH, therefore (68)Ge activity containing waste could directly be used without further interventions. (68)Ge activity containing liquid waste at different HCl concentrations (0.05-1.0 M HCl), was recirculated at 1 mL/min. With Zeolite in the recirculation system, (68)Ge activity showed highest sorption.

  10. Chemistry Dashboard

    Science.gov (United States)

    The Chemistry Dashboard is part of a suite of dashboards developed by EPA to help evaluate the safety of chemicals. The Chemistry Dashboard provides access to a variety of information on over 700,000 chemicals currently in use.

  11. Biophysical chemistry.

    Science.gov (United States)

    Häussinger, Daniel; Pfohl, Thomas

    2010-01-01

    Biophysical chemistry at the Department of Chemistry, University of Basel, covers the NMR analysis of protein-protein interaction using paramagnetic tags and sophisticated microscopy techniques investigating the dynamics of biological matter.

  12. Colour Chemistry

    Science.gov (United States)

    Griffiths, J.; Rattee, I. D.

    1973-01-01

    Discusses the course offerings in pure color chemistry at two universities and the three main aspects of study: dyestuff chemistry, color measurement, and color application. Indicates that there exists a constant challenge to ingenuity in the subject discipline. (CC)

  13. Division of Analytical Chemistry, 1998

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    1999-01-01

    The article recounts the 1998 activities of the Division of Analytical Chemistry (DAC- formerly the Working Party on Analytical Chemistry, WPAC), which body is a division of the Federation of European Chemical Societies (FECS). Elo Harald Hansen is the Danish delegate, representing The Danish...... Chemical Society/The Society for Analytical Chemistry....

  14. Positronium chemistry

    CERN Document Server

    Green, James

    1964-01-01

    Positronium Chemistry focuses on the methodologies, reactions, processes, and transformations involved in positronium chemistry. The publication first offers information on positrons and positronium and experimental methods, including mesonic atoms, angular correlation measurements, annihilation spectra, and statistical errors in delayed coincidence measurements. The text then ponders on positrons in gases and solids. The manuscript takes a look at the theoretical chemistry of positronium and positronium chemistry in gases. Topics include quenching, annihilation spectrum, delayed coincidence

  15. Mathematical problems for chemistry students

    CERN Document Server

    Pota, Gyorgy

    2011-01-01

    Mathematical Problems for Chemistry Students has been compiled and written (a) to help chemistrystudents in their mathematical studies by providing them with mathematical problems really occurring in chemistry (b) to help practising chemists to activate their applied mathematical skills and (c) to introduce students and specialistsof the chemistry-related fields (physicists, mathematicians, biologists, etc.) intothe world of the chemical applications.Some problems of the collection are mathematical reformulations of those in the standard textbooks of chemistry, others we

  16. Research activity of institute of physical chemistry of Russian Academy of sciences in the field of nuclear fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Pikaev, A.K. [Institute of Physical Chemistry of Russian Academy of Sciences, Moscow (Russian Federation)

    2000-07-01

    The report is a brief review of the most important directions in research activity of the Institute of Physical Chemistry of RAS (Moscow) in the field of nuclear fuel cycle. The main attention is paid to researches and developments on liquid radioactive waste management including the removal of wastes to deep geological formations and the immobilization of the wastes. In particular, the data from the study on the properties of new, basaltic-like matrices for the immobilization are presented. The results of research on gas evolution from the systems modeling liquid high-level radioactive wastes are considered. The separation of some radionuclides from irradiated nuclear and the production of radiation sources by various methods are discussed. (author)

  17. Carbonate Chemistry Dynamics in an Area of Active Gas Seepage: the Hudson Canyon, US Atlantic Margin

    Science.gov (United States)

    Garcia-Tigreros Kodovska, F.; Kessler, J. D.; Leonte, M.; Chepigin, A.; Kellermann, M. Y.; Arrington, E. C.; Valentine, D. L.

    2015-12-01

    The fate of oceanic methane and its impact on the global climate has been of particular interest to the global community. The potential for vast amounts of methane to be emitted from the seafloor into the atmosphere due to gas hydrate decomposition has been under scientific evaluation. However, despite the great extent of these geological reservoirs, much of the methane released from the seafloor in deep ocean environments does not reach the atmosphere. Once dissolved in ocean water, the emitted methane can be microbially converted to either carbon dioxide or assimilated to biomass. Here, we will present results from a research cruise to the Hudson Canyon, northern US Atlantic Margin, where we investigated changes in ocean water carbonate chemistry induced by the oxidation of methane released from gas seeps. We will be presenting high precision pH data as well as methane and DIC concentrations, natural stable isotopes, and methane oxidation rates collected inside and adjacent to the Hudson Canyon in the summer of 2014.

  18. Rosetta/VIRTIS investigation of the chemistry and activity of comet 67P/Churyumov-Gerasimenko

    Science.gov (United States)

    Bockelee-Morvan, Dominique; Drossart, Pierre; Piccioni, Giuseppe; Migliorini, Alessandra; Erard, Stéphane; Capaccioni, Fabrizio; Filacchione, Gianrico; Fougere, Nicolas; Leyrat, Cedric; Crovisier, Jacques; Capaccioni, Fabrizio

    2016-07-01

    The composition of cometary ices inside cometary nuclei provides clues to the chemistry of the protoplanetary disk where they formed, 4.6 Gyr ago. These ices sublimate when the body approches the Sun, so that the coma molecular species give insights on the nucleus surface and sub-surface composition. So far, most investigations of the coma chemical composition were performed from telescopic observations from the ground or space plateforms. Since August 2014, the ESA/Rosetta spacecraft has been investigating the nucleus and inner coma of 67P/Churyumov-Gerasimenko. This talk will present an overview of the results obtained by the Visual and Infrared Thermal Imaging Spectrometer (VIRTIS) instrument onboard Rosetta, focussing on observations of molecular species. VIRTIS is composed of two channels. The VIRTIS-M channel is a spectro-imager covering the 0.27-5.1 microns range, which allowed us to map the spatial distribution of H2O and CO2 (Migliorini et al. 2016, A&A in press). VIRTIS-H is a high-spectral resolution spectrometer covering the 2-5 microns range. Spectra obtained with VIRTIS-H show signatures of H2O, CO2 (both fundamental and hot bands), 13CO2, CH4 and other C-H bearing species (Bockelee-Morvan et al. A&A, 583, A6,2015). VIRTIS is a key instrument to investigate regional, diurnal and seasonal variations of the comet outgassing.

  19. Design, synthesis, and anticancer activity of novel berberine derivatives prepared via CuAAC "click" chemistry as potential anticancer agents.

    Science.gov (United States)

    Jin, Xin; Yan, Tian-Hua; Yan, Lan; Li, Qian; Wang, Rui-Lian; Hu, Zhen-Lin; Jiang, Yuan-Ying; Sun, Qing-Yan; Cao, Yong-Bing

    2014-01-01

    A series of novel derivatives of phenyl-substituted berberine triazolyls has been designed and synthesized via copper-catalyzed azide-alkyne cycloaddition click chemistry in an attempt to develop antitumor agents. All of the compounds were evaluated for anticancer activity against a panel of three human cancer cell lines, including MCF-7 (breast), SW-1990 (pancreatic), and SMMC-7721 (liver) and the noncancerous human umbilical vein endothelial cell (HUVEC) cell lines. The results indicated that most of the compounds displayed notable anticancer activities against the MCF-7 cells compared with berberine. Among these derivatives, compound 16 showed the most potent inhibitory activity against the SW-1990 and SMMC-7721 cell lines, with half-maximal inhibitory concentration (IC50) values of 8.54±1.97 μM and 11.87±1.83 μM, respectively. Compound 36 exhibited the most potent inhibitory activity against the MCF-7 cell line, with an IC50 value of 12.57±1.96 μM. Compound 16 and compound 36 exhibited low cytotoxicity in the HUVEC cell line, with IC50 values of 25.49±3.24 μM and 30.47±3.47 μM. Furthermore, compounds 14, 15, 16, 17, 18, 32, and 36 exhibited much better selectivity than berberine toward the normal cell line HUVEC.

  20. Forensic chemistry.

    Science.gov (United States)

    Bell, Suzanne

    2009-01-01

    Forensic chemistry is unique among chemical sciences in that its research, practice, and presentation must meet the needs of both the scientific and the legal communities. As such, forensic chemistry research is applied and derivative by nature and design, and it emphasizes metrology (the science of measurement) and validation. Forensic chemistry has moved away from its analytical roots and is incorporating a broader spectrum of chemical sciences. Existing forensic practices are being revisited as the purview of forensic chemistry extends outward from drug analysis and toxicology into such diverse areas as combustion chemistry, materials science, and pattern evidence.

  1. Radiological and Environmental Research Division annual report. Fundamental molecular physics and chemistry, June 1975--September 1976. [Summaries of research activities at Argonne National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    None

    1976-01-01

    A summary of research activities in the fundamental molecular physics and chemistry section at Argonne National Laboratory from July 1975 to September 1976 is presented. Of the 40 articles and abstracts given, 24 have been presented at conferences or have been published and will be separately abstracted. Abstracts of the remaining 16 items appear in this issue of ERA. (JFP)

  2. Geology and chemistry of hydrothermal deposits from active submarine volcano Loihi, Hawaii

    Energy Technology Data Exchange (ETDEWEB)

    Malahoff, A. (National Ocean Survey-NOAA, Rockville, MD); McMurtry, G.M.; Wiltshire, J.C.; Yeh, H.W.

    1982-07-15

    High-resolution bathymetric surveys, bottom photography and sample analyses show that Loihi Seamount at the southernmost extent of the Hawaiian hotspot is an active, young submarine volcano that is probably the site of an emerging Hawaiian island. Hydrothermal deposits sampled from the active summit rift system were probably formed by precipitation from cooling vent fluids or during cooling and oxidation of high-temperature polymetallic sulphide assemblages. No exotic benthic fauna were found to be associated with the presently active hydrothermal vents mapped.

  3. Isolation, biological activity, synthesis, and medicinal chemistry of the pederin/mycalamide family of natural products.

    Science.gov (United States)

    Mosey, R Adam; Floreancig, Paul E

    2012-09-01

    This review highlights the broad range of science that has arisen from the isolation of pederin, the mycalamides, theopederins, and onnamides, and psymberin. Specific topics include structure determination, biological activity, synthesis, and analog preparation and analysis.

  4. Chemistry, antioxidant, antibacterial and antifungal activities of volatile oils and their components.

    Science.gov (United States)

    De Martino, Laura; De Feo, Vincenzo; Fratianni, Florinda; Nazzaro, Filomena

    2009-12-01

    The present paper reports the chemical composition, antioxidant and antibacterial activities of several essential oils and their components. Analysis showed that three oils (Carum carvi L., Verbena officinalis L. and Majorana hortensis L.) contained predominantly oxygenated monoterpenes, while others studied (Pimpinella anisum L., Foeniculum vulgare Mill.) mainly contained anethole. C. carvi, V. officinalis and M. hortensis oils exhibited the most potent antioxidant activity, due their contents of carvacrol, anethole and estragol. Antibacterial action was assessed against a range of pathogenic and useful bacteria and fungi of agro-food interest. V. officinalis and C. carvi oils proved the most effective, in particular against Bacillus cereus and Pseudomonas aeruginosa. Carvacrol proved most active against Escherichia coli, and completely inhibited the growth of Penicillium citrinum. The oils proved inactive towards some Lactobacilli strains, whereas single components showed an appreciable activity. These results may be important for use of the essential oils as natural preservatives for food products.

  5. Green chemistry approach to the synthesis of potentially bioactive aminobenzylated Mannich bases through active hydrogen compounds

    Directory of Open Access Journals (Sweden)

    S. L. VASOYA

    2005-10-01

    Full Text Available An efficient and high yield method for the synthesis of aminobenzylated Mannich bases is described. The synthesis occurs in aqueous medium at 0 ºC. The compounds show moderate antitubercular and antimicrobial activities.

  6. Terpenes from the soft corals of the genus Sarcophyton: chemistry and biological activities.

    Science.gov (United States)

    Liang, Lin-Fu; Guo, Yue-Wei

    2013-12-01

    This review covers structural diversity and biological activities of terpenes from soft corals of the genus of Sarcophyton, reported from 1995 to July, 2011. During this period, besides undefined species, 16 species of the genus Sarcophyton, from different geographical areas, had been chemically examined. Two hundred and five terpenes had been isolated from this genus, including eleven sesquiterpenes, 165 diterpenes, 29 biscembranoids, some of which had novel skeletons. They exhibited various biological features, such as antifeedant, anti-inflammatory, antiviral, and antifouling activities.

  7. 'Unconventional' coordination chemistry by metal chelating fragments in a metalloprotein active site.

    Science.gov (United States)

    Martin, David P; Blachly, Patrick G; Marts, Amy R; Woodruff, Tessa M; de Oliveira, César A F; McCammon, J Andrew; Tierney, David L; Cohen, Seth M

    2014-04-01

    The binding of three closely related chelators: 5-hydroxy-2-methyl-4H-pyran-4-thione (allothiomaltol, ATM), 3-hydroxy-2-methyl-4H-pyran-4-thione (thiomaltol, TM), and 3-hydroxy-4H-pyran-4-thione (thiopyromeconic acid, TPMA) to the active site of human carbonic anhydrase II (hCAII) has been investigated. Two of these ligands display a monodentate mode of coordination to the active site Zn(2+) ion in hCAII that is not recapitulated in model complexes of the enzyme active site. This unprecedented binding mode in the hCAII-thiomaltol complex has been characterized by both X-ray crystallography and X-ray spectroscopy. In addition, the steric restrictions of the active site force the ligands into a 'flattened' mode of coordination compared with inorganic model complexes. This change in geometry has been shown by density functional computations to significantly decrease the strength of the metal-ligand binding. Collectively, these data demonstrate that the mode of binding by small metal-binding groups can be significantly influenced by the protein active site. Diminishing the strength of the metal-ligand bond results in unconventional modes of metal coordination not found in typical coordination compounds or even carefully engineered active site models, and understanding these effects is critical to the rational design of inhibitors that target clinically relevant metalloproteins.

  8. Antibacterial activity of biochemically capped iron oxide nanoparticles: A view towards green chemistry.

    Science.gov (United States)

    Irshad, Rabia; Tahir, Kamran; Li, Baoshan; Ahmad, Aftab; R Siddiqui, Azka; Nazir, Sadia

    2017-05-01

    A green approach to fabricate nanoparticles has been evolved as a revolutionary discipline. Eco-compatible reaction set ups, use of non-toxic materials and production of highly active biological and photocatalytic products are few benefits of this greener approach. Here, we introduce a green method to synthesize Fe oxide NPs using Punica granatum peel extract. The formation of Fe oxide NPs was optimized using different concentrations of peel extract (20mL, 40mL and 60mL) to achieve small size and better morphology. The results indicate that the FeNPs, obtained using 40mL concentration of peel extract possess the smallest size. The morphology, size and crystallinity of NPs was confirmed by implementing various techniques i.e. UV-Vis spectroscopy, X-ray diffraction, Scanning Electron Microscopy and Electron Diffraction Spectroscopy. The bio-chemicals responsible for reduction and stabilization of FeNPs were confirmed by FT-IR analysis. The biogenic FeNPs were tested for their size dependent antibacterial activity. The biogenic FeNPs prepared in 40mL extract concentrations exhibited strongest antibacterial activity against Pseudomonas aeruginosa i.e. 22 (±0.5) mm than FeNPs with 20mL and 60mL extract concentrations i.e. 18 (±0.4) mm and 14 (±0.3) mm respectively. The optimized FeNPs with 40mL peel extract are not only highly active for ROS generation but also show no hemolytic activity. Thus, FeNPs synthesized using the greener approach are found to have high antibacterial activity along with biocompatibility. This high antibacterial activity can be referred to small size and large surface area. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. The Role of Green Chemistry Activities in Fostering Secondary School Students' Understanding of Acid-Base Concepts and Argumentation Skills

    Science.gov (United States)

    Karpudewan, Mageswary; Roth, Wolff Michael; Sinniah, Devananthini

    2016-01-01

    In a world where environmental degradation is taking on alarming levels, understanding, and acting to minimize, the individual environmental impact is an important goal for many science educators. In this study, a green chemistry curriculum--combining chemistry experiments with everyday, environmentally friendly substances with a student-centered…

  10. Surface chemistry and acid-base activity of Shewanella putrefaciens: Cell wall charging and metal binding to bacterial cell walls

    NARCIS (Netherlands)

    Claessens, Jacqueline Wilhelmien

    2006-01-01

    To gain insight into the surface chemistry of live microorganisms, pH stat experiments are combined with analyses of the time-dependent changes in solution chemistry using suspensions of live cells of Shewanella putrefaciens. The results of this study illustrate the complex response of the live

  11. Surface chemistry and acid-base activity of Shewanella putrefaciens : Cell wall charging and metal binding to bacterial cell walls

    NARCIS (Netherlands)

    Claessens, J.W.

    2006-01-01

    To gain insight into the surface chemistry of live microorganisms, pH stat experiments are combined with analyses of the time-dependent changes in solution chemistry using suspensions of live cells of Shewanella putrefaciens. The results of this study illustrate the complex response of the live

  12. Engaging Participation and Promoting Active Learning through Student Usage of the Internet to Create Notes for General Chemistry in Class

    Science.gov (United States)

    Henry, Renee Monica

    2017-01-01

    Reported here is a study of an interactive component to General Chemistry I and General Chemistry II where a new pedagogy for taking notes in class was developed. These notes, called key word created class notes, prompted students to locate information using the Internet guided by a key word. Reference Web sites were added to a next generation of…

  13. Students' perceptions of teaching in context-based and traditional chemistry classrooms : Comparing content, learning activities, and interpersonal perspectives

    NARCIS (Netherlands)

    Overman, Michelle; Vermunt, Jan D.; Meijer, Paulien C.; Bulte, Astrid M W; Brekelmans, Mieke

    2014-01-01

    Context-based curriculum reforms in chemistry education are thought to bring greater diversity to the ways in which chemistry teachers organize their teaching. First and foremost, students are expected to perceive this diversity. However, empirical research on how students perceive their teacher's t

  14. [Investigation of biologically active compounds at the Department of Organic Chemistry of University of Debrecen 1992-2009. Part III].

    Science.gov (United States)

    Antus, Sándor

    2010-01-01

    The author briefly reviews the beginning of the carbohydrate chemistry in Hungary with special regard to the results achieved at the Department of Organic Chemistry of University of Debrecen and summarizes the most important synthetic and pharmaceutical results obtained in this field between 1992-2009, part III.

  15. The Role of Green Chemistry Activities in Fostering Secondary School Students' Understanding of Acid-Base Concepts and Argumentation Skills

    Science.gov (United States)

    Karpudewan, Mageswary; Roth, Wolff Michael; Sinniah, Devananthini

    2016-01-01

    In a world where environmental degradation is taking on alarming levels, understanding, and acting to minimize, the individual environmental impact is an important goal for many science educators. In this study, a green chemistry curriculum--combining chemistry experiments with everyday, environmentally friendly substances with a student-centered…

  16. Organic chemistry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-08-15

    This book with sixteen chapter explains organic chemistry on linkage isomerism such as alkane, cycloalkane, alkene, aromatic compounds, stereo selective isomerization, aromatic compounds, stereo selective isomerization, organic compounds, stereo selective isomerization, organic halogen compound, alcohol, ether, aldehyde and ketone, carboxylic acid, dicarboxylic acid, fat and detergent, amino, carbohydrate, amino acid and protein, nucleotide and nucleic acid and spectroscopy, a polymer and medical chemistry. Each chapter has introduction structure and characteristic and using of organic chemistry.

  17. Computational chemistry

    OpenAIRE

    2000-01-01

    Computational chemistry has come of age. With significant strides in computer hardware and software over the last few decades, computational chemistry has achieved full partnership with theory and experiment as a tool for understanding and predicting the behavior of a broad range of chemical, physical, and biological phenomena. The Nobel Prize award to John Pople and Walter Kohn in 1998 highlighted the importance of these advances in computational chemistry. With massively parallel computers ...

  18. Fighting Fenton Chemistry: A Highly Active Iron(III) Tetracarbene Complex in Epoxidation Catalysis.

    Science.gov (United States)

    Kück, Jens W; Anneser, Markus R; Hofmann, Benjamin; Pöthig, Alexander; Cokoja, Mirza; Kühn, Fritz E

    2015-12-07

    Organometallic Fe complexes with exceptionally high activities in homogeneous epoxidation catalysis are reported. The compounds display Fe(II) and Fe(III) oxidation states and bear a tetracarbene ligand. The more active catalyst exhibits activities up to 183 000 turnovers per hour at room temperature and turnover numbers of up to 4300 at -30 °C. For the Fe(III) complex, a decreased Fenton-type reactivity is observed compared with Fe(II) catalysts reported previously as indicated by a substantially lower H2 O2 decomposition and higher (initial) turnover frequencies. The dependence of the catalyst performance on the catalyst loading, substrate, water addition, and the oxidant is investigated. Under all applied conditions, the advantageous nature of the use of the Fe(III) complex is evident.

  19. Electrochemical Sensing, Photocatalytic and Biological Activities of ZnO Nanoparticles: Synthesis via Green Chemistry Route

    Science.gov (United States)

    Yadav, L. S. Reddy; Archana, B.; Lingaraju, K.; Kavitha, C.; Suresh, D.; Nagabhushana, H.; Nagaraju, G.

    2016-05-01

    In this paper, we have successfully synthesized ZnO nanoparticles (Nps) via solution combustion method using sugarcane juice as the novel fuel. The structure and morphology of the synthesized ZnO Nps have been analyzed using various analytical tools. The synthesized ZnO Nps exhibit excellent photocatalytic activity for the degradation of methylene blue dye, indicating that the ZnO Nps are potential photocatalytic semiconductor materials. The synthesized ZnO Nps also show good electrochemical sensing of dopamine. ZnO Nps exhibit significant bactericidal activity against Klebsiella aerogenes, Pseudomonas aeruginosa, Eschesichia coli and Staphylococcus aureus using agar well diffusion method. Furthermore, the ZnO Nps show good antioxidant activity by potentially scavenging 1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The above studies clearly demonstrate versatile applications of ZnO synthesized by simple eco-friendly route.

  20. An impression on current developments in the technology, chemistry, and biological activities of ginger (Zingiber officinale Roscoe).

    Science.gov (United States)

    Kubra, I Rahath; Rao, L Jagan Mohan

    2012-01-01

    Ginger rhizome (Zingiber officinale Roscoe) is widely cultivated as a spice for its aromatic and pungent components. The essential oil and oleoresins from ginger are valuable products responsible for the characteristic flavor and pungency. Both are used in several food products such as soft beverages and also in many types of pharmaceutical formulations. More than 100 compounds have been reported from ginger, some of which are isolated and characterized, others are tentatively identified by GC-MS and / or LC-MS. [6]-Gingerol, the major gingerol in ginger rhizomes, has been found to possess many interesting pharmacological and physiological activities, such as anti-inflammatory, analgesic, and cardiotonic effects. Ginger is considered as "generally recognized as safe" (GRAS) by Food and Drug Administration (FDA), USA. Due to all these properties, ginger has gained considerable attention in developed countries in recent years, especially for its use in the treatment of inflammatory conditions. The present review is a persuasive presentation of the current information on processing, chemistry, biological activities, and medicinal uses of ginger. Further studies are required for the validation of the beneficial uses. Formulation for novel products and new usages may emerge in the years to come, based on the revealed results of various studies.

  1. Crystal-chemistry insight into the photocatalytic activity of BiOCl x Br1- x nanoplate solid solutions

    Science.gov (United States)

    Xu, Huan-Yan; Han, Xu; Tan, Qu; Wu, Ke-Jia; Qi, Shu-Yan

    2017-06-01

    In this study, a facile alcoholysis method was developed to synthesize BiOCl x Br1- x nanoplates at room temperature and atmospheric pressure. In this route, strong acid or alkaline environment was absolutely avoided to realize the high exposure of {001} crystal facets. The regular changes in XRD peaks and cell parameters as a function of the Br content strongly declared that the obtained BiOCl x Br1- x products belonged to a group of solid solutions. The 2D nanosheets with in-plane wrinkles were clearly observed in TEM images. Interestingly, as the Br content increased, band gaps of BiOCl x Br1- x solid solutions gradually decreased. The photocatalytic degradation of RhB under simulated sunlight irradiation indicated that BiOCl0.5Br0.5 had the best photocatalytic activity. From the viewpoint of crystal chemistry, the photocatalytic activity of BiOCl x Br1- x solid solutions was closely related with the exposure amount of {001} facets, interlayer spacing of (001) plane and energy-level position of valence band.

  2. Green Chemistry Approach for Efficient Synthesis of Schiff Bases of Isatin Derivatives and Evaluation of Their Antibacterial Activities

    Directory of Open Access Journals (Sweden)

    Jnyanaranjan Panda

    2013-01-01

    Full Text Available Microwave-assisted organic synthesis, a green chemistry approach, is nowadays widely used in the drug synthesis. Microwave-assisted synthesis improves both throughput and turnaround time for medicinal chemists by offering the benefits of drastically reduced reaction times, increased yields, and pure products. Schiff bases are the important class of organic compounds due to their flexibility, and structural diversities due to the presence of azomethine group which is helpful for elucidating the mechanism of transformation and rasemination reaction in biological system. This novel compound could also act as valuable ligands for the development of new chemical entities. In the present work, some Schiff bases of Isatin derivatives was synthesized using microwave heating method. Schiff base of Isatin were synthesized by condensation of the keto group of Isatin with different aromatic primary amines. They were characterized by means of spectral data and subsequently subjected to the in vitro antibacterial activities against gram positive and gram negative strains of microbes. It was observed that the compound with electron withdrawing substituents exhibited good antibacterial activities against almost all the micro organisms.

  3. The Application of SCC-DV-Xα Computational Method of Quantum Chemistry in Cement Chemistry

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    It has been explored why quantum chemistry is applied to the research field of cement chemistry. The fundamental theory of SCC-DV-Xα computational method of quantum chemistry is synopsized. The results obtained by computational quantum chemistry method in recent years of valence-bond structures and hydration activity of some cement clinker minerals, mechanical strength and stabilization of some hydrates are summarized and evaluated. Finally the prospects of the future application of quantum chemistry to cement chemistry are depicted.

  4. Using the Activity Model of Inquiry to Enhance General Chemistry Students' Understanding of Nature of Science

    Science.gov (United States)

    Marchlewicz, Sara C.; Wink, Donald J.

    2011-01-01

    Nature of science refers to the processes of scientific activity and the social and cultural premises involved in the creation of scientific knowledge. Having an informed view of nature of science is important in the development of scientifically literate citizens. However, students often come to the classroom with misconceptions about nature of…

  5. The Chemistry of Self-Heating Food Products: An Activity for Classroom Engagement

    Science.gov (United States)

    Oliver-Hoyo, Maria T.; Pinto, Gabriel; Llorens-Molina, Juan Antonio

    2009-01-01

    Two commercial self-heating food products have been used to apply chemical concepts such as stoichiometry, enthalpies of reactions and solutions, and heat transfer in a classroom activity. These products are the self-heating beverages sold in Europe and the Meals, Ready to Eat or MREs used primarily by the military in the United States. The main…

  6. Using the Activity Model of Inquiry to Enhance General Chemistry Students' Understanding of Nature of Science

    Science.gov (United States)

    Marchlewicz, Sara C.; Wink, Donald J.

    2011-01-01

    Nature of science refers to the processes of scientific activity and the social and cultural premises involved in the creation of scientific knowledge. Having an informed view of nature of science is important in the development of scientifically literate citizens. However, students often come to the classroom with misconceptions about nature of…

  7. Biologically active perspective synthesis of heteroannulated 8-nitroquinolines with green chemistry approach.

    Science.gov (United States)

    Arasakumar, Thangaraj; Mathusalini, Sadasivam; Gopalan, Subashini; Shyamsivappan, Selvaraj; Ata, Athar; Mohan, Palathurai Subramaniam

    2017-04-01

    A new class of pyrazolo[4,3-c]quinoline (5a-i, 7a-b) and pyrano[3,2-c]quinoline (9a-i) derivatives were designed and synthesized in moderate to good yields by microwave conditions. To enhance the yield of pyrano[3,2-c]quinoline derivatives, multicomponent one-pot synthesis has been developed. The synthesized compounds were identified by spectral and elemental analyses. Compounds 9a and 9i showed good antibacterial activity against Gram-positive and Gram-negative bacterial strains. All of the new compounds exhibited weak to moderate antioxidant activity, compound 9d exerted significant antioxidant power. The cytotoxicity of these compounds were also evaluated against MCF-7 (breast) and A549 (Lung) cancer cell lines. Most of the compounds displayed moderate to good cytotoxic activity against these cell lines. Compound 9i was found to be significantly active in this assay and also induced cell death by apoptosis. Molecular docking studies were carried out using EGFR inhibitor in order to determine the molecular interactions.

  8. The Chemistry of Self-Heating Food Products: An Activity for Classroom Engagement

    Science.gov (United States)

    Oliver-Hoyo, Maria T.; Pinto, Gabriel; Llorens-Molina, Juan Antonio

    2009-01-01

    Two commercial self-heating food products have been used to apply chemical concepts such as stoichiometry, enthalpies of reactions and solutions, and heat transfer in a classroom activity. These products are the self-heating beverages sold in Europe and the Meals, Ready to Eat or MREs used primarily by the military in the United States. The main…

  9. 浅析化学课堂活动的问题与策略%An Analysis of the Problems and Strategies in the Classroom Activities of Chemistry

    Institute of Scientific and Technical Information of China (English)

    杜良行

    2016-01-01

    Quality classroom activities are guarantee for the achievement of teaching aims and the development of students’abilities. The article analyzes the problems in chemistry classroom activities and puts forward several strategies to optimize the classroom activities,which brings into better play of the role of classroom activities and im-proves the quality of chemistry teaching.%优质的课堂活动是实现教学目标,发展学生能力的保障。本文剖析了当前化学课堂活动中发现的问题,提出优化课堂活动的策略。以利于更好地发挥课堂活动的作用,提升化学教学的质量。

  10. Pore-fluid chemistry along the main axis of an active lobe at the Congo deep-sea fan

    Science.gov (United States)

    Croguennec, C.; Ruffine, L.; Guyader, V.; Le Bruchec, J.; Ruesch, B.; Caprais, J.; Cathalot, C.; de Prunelé, A.; Germain, Y.; Bollinger, C.; Dennielou, B.; Olu, K.; Rabouille, C.

    2013-12-01

    The distal lobes of the Congo deep-sea fan constitute a unique in situ laboratory to study early diagenesis of marine sediments. They are located at water depth of about 5000 m and result from the deposition of sediment transported by turbidity currents along the channel-levee systems and submarine canyon connected to the Congo River. Thus, a huge amount of organic matter, transported from the river to the lobes, undergoes decomposition processes involving different oxidants present within the sedimentary column. This drastically changes the chemistry of the pore fluids, allowing the occurence of a succession of biogeochemical processes. The present study is part of an ongoing project which aims at better understanding the role and the fate of organic matter transported to the lobe systems, as well as its implication in the distribution of the living communities encountered there. Thus, pore fluids have been sampled from 8 Calypso cores in order to determine the concentration of dissolved elements. Five sites have been investigated: four of them are located along the main axis of a currently active lobe, the last one being located on a lobe disconnected from the chenals. The analyses of methane, major (Cl, SO4, Mg, Ca, K, Na) and minor (Sr, Ba, B, Li, Mn) elements have been carried out along with total alkalinity determination. The resulting profiles show a highly heterogeneous pore-fluid chemistry. Sulphate concentration near the seawater/sediment interface varies from 3 to 29 mM, indicating intense sulphate reduction. Surprisingly the lowest values are found at the site which is disconnected from the active lobe. The manganese cycle is well defined for all cores. The core recovered at the more distal lobe exhibits very peculiar pore-fluid profiles which are likely related to a geological event, most likely sediment slide and remobilization. References: Babonneau, N., Savoye, B., Cremer, M. & Klein, B., 2002. Morphology and architecture of the present canyon and

  11. Hydrochemical evaluation of the influences of mining activities on river water chemistry in central northern Mongolia.

    Science.gov (United States)

    Batsaikhan, Bayartungalag; Kwon, Jang-Soon; Kim, Kyoung-Ho; Lee, Young-Joon; Lee, Jeong-Ho; Badarch, Mendbayar; Yun, Seong-Taek

    2017-01-01

    Although metallic mineral resources are most important in the economy of Mongolia, mining activities with improper management may result in the pollution of stream waters, posing a threat to aquatic ecosystems and humans. In this study, aiming to evaluate potential impacts of metallic mining activities on the quality of a transboundary river (Selenge) in central northern Mongolia, we performed hydrochemical investigations of rivers (Tuul, Khangal, Orkhon, Haraa, and Selenge). Hydrochemical analysis of river waters indicates that, while major dissolved ions originate from natural weathering (especially, dissolution of carbonate minerals) within watersheds, they are also influenced by mining activities. The water quality problem arising from very high turbidity is one of the major environmental concerns and is caused by suspended particles (mainly, sediment and soil particles) from diverse erosion processes, including erosion of river banks along the meandering river system, erosion of soils owing to overgrazing by livestock, and erosion by human activities, such as mining and agriculture. In particular, after passing through the Zaamar gold mining area, due to the disturbance of sediments and soils by placer gold mining, the Tuul River water becomes very turbid (up to 742 Nephelometric Turbidity Unit (NTU)). The Zaamar area is also the contamination source of the Tuul and Orkhon rivers by Al, Fe, and Mn, especially during the mining season. The hydrochemistry of the Khangal River is influenced by heavy metal (especially, Mn, Al, Cd, and As)-loaded mine drainage that originates from a huge tailing dam of the Erdenet porphyry Cu-Mo mine, as evidenced by δ(34)S values of dissolved sulfate (0.2 to 3.8 ‰). These two contaminated rivers (Tuul and Khangal) merge into the Orkhon River that flows to the Selenge River near the boundary between Mongolia and Russia and then eventually flows into Lake Baikal. Because water quality problems due to mining can be critical

  12. The chemistry and biological activity of herbs used in Flor-Essence herbal tonic and Essiac.

    Science.gov (United States)

    Tamayo, C; Richardson, M A; Diamond, S; Skoda, I

    2000-02-01

    The herbal mixtures, Essiac and Flor-Essence, are sold as nutritional supplements and used by patients to treat chronic conditions, particularly cancer. Evidence of anticancer activity for the herbal teas is limited to anecdotal reports recorded for some 40 years in Canada. Individual case reports suggest that the tea improves quality of life, alleviates pain, and in some cases, impacts cancer progression among cancer patients. Experimental studies with individual herbs have shown evidence of biological activity including antioxidant, antioestrogenic, immunostimulant, antitumour, and antiocholeretic actions. However, research that demonstrates these positive effects in the experimental setting has not been translated to the clinical arena. Currently, no clinical studies of Essiac or Flor-essence are published, but a clinical study is being planned at the British Columbia Cancer Agency by the University of Texas-Center for Alternative Medicine (UT-CAM) and Tzu-Chi Institute for Complementary and Alternative Medicine.

  13. Ant-mediated effects on spruce litter decomposition, solution chemistry, and microbial activity

    DEFF Research Database (Denmark)

    Stadler, B.; Schramm, Andreas; Kalbitz, K.

    2006-01-01

    Forest management practices often generate clear-cut patches, which may be colonized by ants not present in the same densities in mature forests. In addition to the associated changes in abiotic conditions ants can initiate processes, which do not occur in old-growth stands. Here, we analyse...... the effects of ants and aphid honeydew on litter solution of Norway spruce, microbial enzyme activities, and needle decomposition in a field and greenhouse experiment during summer 2003. In the field, low ant densities had relatively little effects on litter solution 30 cm away from a tree trunk....... The presence of ants resulted in a changed composition of dissolved organic matter (DOM) with more aromatic and complex compounds, and microbial enzyme activity was significantly higher in litter extracts from the ant treatment compared to the honeydew and control treatment. However, mass loss, litter %C...

  14. Pore solution chemistry of alkali-activated ground granulated blast-furnace slag

    Energy Technology Data Exchange (ETDEWEB)

    Song, S.; Jennings, H.M. [Northwestern Univ., Evanston, IL (United States)

    1999-02-01

    The chemical composition and pH of the pore solution extracted from six different ground granulated blast-furnace slag (GGBFS) pastes were determined. The concentrations of Si, Ca, Al, and Mg are functions of the pH of the aqueous phase, with high pH associated with the higher concentrations of Si and Al and the lower concentrations of Ca and Mg. When GGBFS is mixed with an aqueous phase with pH higher than 11.5, the reaction is activated or accelerated. The main hydration product was identified as C-S-H, and hydrotalcite, at later stages of hydration, was observed in the pastes with an aqueous phase of a high pH. The effect of pore solution on the alkali activation of GGBFS is discussed with reference to the hydration products.

  15. Human frataxin activates Fe-S cluster biosynthesis by facilitating sulfur transfer chemistry.

    Science.gov (United States)

    Bridwell-Rabb, Jennifer; Fox, Nicholas G; Tsai, Chi-Lin; Winn, Andrew M; Barondeau, David P

    2014-08-05

    Iron-sulfur clusters are ubiquitous protein cofactors with critical cellular functions. The mitochondrial Fe-S assembly complex, which consists of the cysteine desulfurase NFS1 and its accessory protein (ISD11), the Fe-S assembly protein (ISCU2), and frataxin (FXN), converts substrates l-cysteine, ferrous iron, and electrons into Fe-S clusters. The physiological function of FXN has received a tremendous amount of attention since the discovery that its loss is directly linked to the neurodegenerative disease Friedreich's ataxia. Previous in vitro results revealed a role for human FXN in activating the cysteine desulfurase and Fe-S cluster biosynthesis activities of the Fe-S assembly complex. Here we present radiolabeling experiments that indicate FXN accelerates the accumulation of sulfur on ISCU2 and that the resulting persulfide species is viable in the subsequent synthesis of Fe-S clusters. Additional mutagenesis, enzyme kinetic, UV-visible, and circular dichroism spectroscopic studies suggest conserved ISCU2 residue C104 is critical for FXN activation, whereas C35, C61, and C104 are all essential for Fe-S cluster formation on the assembly complex. These results cannot be fully explained by the hypothesis that FXN functions as an iron donor for Fe-S cluster biosynthesis, and further support an allosteric regulator role for FXN. Together, these results lead to an activation model in which FXN accelerates persulfide formation on NFS1 and favors a helix-to-coil interconversion on ISCU2 that facilitates the transfer of sulfur from NFS1 to ISCU2 as an initial step in Fe-S cluster biosynthesis.

  16. Nanostructured manganese oxides as highly active water oxidation catalysts: a boost from manganese precursor chemistry.

    Science.gov (United States)

    Menezes, Prashanth W; Indra, Arindam; Littlewood, Patrick; Schwarze, Michael; Göbel, Caren; Schomäcker, Reinhard; Driess, Matthias

    2014-08-01

    We present a facile synthesis of bioinspired manganese oxides for chemical and photocatalytic water oxidation, starting from a reliable and versatile manganese(II) oxalate single-source precursor (SSP) accessible through an inverse micellar molecular approach. Strikingly, thermal decomposition of the latter precursor in various environments (air, nitrogen, and vacuum) led to the three different mineral phases of bixbyite (Mn2 O3 ), hausmannite (Mn3 O4 ), and manganosite (MnO). Initial chemical water oxidation experiments using ceric ammonium nitrate (CAN) gave the maximum catalytic activity for Mn2 O3 and MnO whereas Mn3 O4 had a limited activity. The substantial increase in the catalytic activity of MnO in chemical water oxidation was demonstrated by the fact that a phase transformation occurs at the surface from nanocrystalline MnO into an amorphous MnOx (1water oxidation in the presence of [Ru(bpy)3 ](2+) (bpy=2,2'-bipyridine) as a sensitizer and peroxodisulfate as an electron acceptor was carried out for all three manganese oxides including the newly formed amorphous MnOx . Both Mn2 O3 and the amorphous MnOx exhibit tremendous enhancement in oxygen evolution during photocatalysis and are much higher in comparison to so far known bioinspired manganese oxides and calcium-manganese oxides. Also, for the first time, a new approach for the representation of activities of water oxidation catalysts has been proposed by determining the amount of accessible manganese centers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Synthesis of new triazole arotinoids analogues via "Click Chemistry" with potential anticancer activity

    Directory of Open Access Journals (Sweden)

    Mariana A. A. Aleixo

    2012-06-01

    Full Text Available Retinoids are  a  class  of  natural  and  synthetic  vitamin A analogues structurally related to all-trans-retinoic acid (ATRA. This class of compounds can inhibit cell proliferation and induce differentiation and apoptosis of cells, and several are used in cancer therapy. Using the concept of bioisosterism, new triazole analogues were designed from the molecular modification of the potent derivative arotinoid AM580. This compound has an amide grouping which is a bioisostere of 1,2,3-triazole ring. Through "Click Chemistry” approach, triazole analogues were obtained by reaction of Huisgen 1,3-dipolar cycloaddition between aryl azides and terminal acetylene, previously synthesized. The reagents used were CuI, triethylamine and mixture of ethanol:water. The first compound synthesized showed anticancer activity, while the second proved to be inactive. The molecular docking results showed that both compounds have high affinity for the retinoid RARα receptor (related to anticancer activity, but probably the second compound has antagonist activity on this receptor.

  18. Evidence for linkages between ecoenzyme activity and soil organic matter chemistry following encroachment of leguminous woody plant into grasslands.

    Science.gov (United States)

    Filley, Timothy; Stott, Diane; Boutton, Thomas; Creamer, Courtney; Olk, Dan

    2010-05-01

    The encroachment of woody plants into grasslands is a worldwide phenomenon. In the Rio Grande Plains of southern Texas, subtropical thorn woodlands dominated by the N-fixing tree Prosopis glandulosa have largely replaced native grasslands as a result of fire suppression and extensive cattle grazing. This land cover change has resulted in the increase of belowground stocks of C, N, and P, changes to the amount and chemical nature of soil-stabilized plant biopolymers, and the composition and activity of soil microbes. Given that extracellular enzymes produced by plants and microbes are the principal means by which complex compounds are degraded and that the production of such enzymes is triggered or suppressed by changes in substrate and nutrient availability we sought to relate how these fundamental changes in this ecosystem are reflected in the activity of soil stabilized ecoenzymes and soil organic matter (SOM) chemistry in this system. We investigated a chronosequence of woody encroachment (14-86 yrs) into a C4-dominant grassland. We related the potential activities of five extracellular enzymes (arylamidase, acid phosphatase, β-glucosidase, β-glucosaminidase (NAGase, polyphenoloxidase (PPO)) and a general marker for hydrolytic activity, fluorescein diacetate (FDA) to the molecular composition and concentration of total hydrolysable amino acids and amino sugars, sugars, as well as CuO extractable lignin and substituted fatty acid to. When normalized to dry weight soil all chemical components increase in concentration with cluster age and all clusters have greater concentrations than background grasslands. All enzymes activities exhibit higher potential activity in woody clusters than grasslands but only NAGase and FDA increase with cluster age when normalized to dry weight of soil. Conversely, when normalized to SOC only lignin phenols, hydroxyl proline, and glucose from cellulose are positively correlated with cluster age indicating a selective accrual with

  19. Water oxidation chemistry of a synthetic dinuclear ruthenium complex containing redox-active quinone ligands.

    Science.gov (United States)

    Isobe, Hiroshi; Tanaka, Koji; Shen, Jian-Ren; Yamaguchi, Kizashi

    2014-04-21

    We investigated theoretically the catalytic mechanism of electrochemical water oxidation in aqueous solution by a dinuclear ruthenium complex containing redox-active quinone ligands, [Ru2(X)(Y)(3,6-tBu2Q)2(btpyan)](m+) [X, Y = H2O, OH, O, O2; 3,6-tBu2Q = 3,6-di-tert-butyl-1,2-benzoquinone; btpyan =1,8-bis(2,2':6',2″-terpyrid-4'-yl)anthracene] (m = 2, 3, 4) (1). The reaction involves a series of electron and proton transfers to achieve redox leveling, with intervening chemical transformations in a mesh scheme, and the entire molecular structure and motion of the catalyst 1 work together to drive the catalytic cycle for water oxidation. Two substrate water molecules can bind to 1 with simultaneous loss of one or two proton(s), which allows pH-dependent variability in the proportion of substrate-bound structures and following pathways for oxidative activation of the aqua/hydroxo ligands at low thermodynamic and kinetic costs. The resulting bis-oxo intermediates then undergo endothermic O-O radical coupling between two Ru(III)-O(•) units in an anti-coplanar conformation leading to bridged μ-peroxo or μ-superoxo intermediates. The μ-superoxo species can liberate oxygen with the necessity for the preceding binding of a water molecule, which is possible only after four-electron oxidation is completed. The magnitude of catalytic current would be limited by the inherent sluggishness of the hinge-like bending motion of the bridged μ-superoxo complex that opens up the compact, hydrophobic active site of the catalyst and thereby allows water entry under dynamic conditions. On the basis of a newly proposed mechanism, we rationalize the experimentally observed behavior of electrode kinetics with respect to potential and discuss what causes a high overpotential for water oxidation by 1.

  20. Molecular simulation of receptors of physiologically active compounds for purposes of medical chemistry

    Science.gov (United States)

    Baskin, Igor I.; Palyulin, Vladimir A.; Zefirov, Nikolai S.

    2009-06-01

    The general strategy of the molecular simulation of biological receptors and their interaction with ligands is considered. The procedures for construction of 3D protein models, molecular docking, evaluation of model quality, determination of the free energy of protein binding with ligands are discussed. The methods of molecular design of new medicaments based on molecular models of biological targets: virtual screening and de novo design, are presented. Examples of the above-listed approaches for the simulation of a number of pharmacologically significant receptors, analysis of receptor-ligand interactions and design of new biologically active organic compounds are given.

  1. Molecular simulation of receptors of physiologically active compounds for purposes of medical chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Baskin, Igor I; Palyulin, Vladimir A; Zefirov, Nikolai S [Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2009-06-30

    The general strategy of the molecular simulation of biological receptors and their interaction with ligands is considered. The procedures for construction of 3D protein models, molecular docking, evaluation of model quality, determination of the free energy of protein binding with ligands are discussed. The methods of molecular design of new medicaments based on molecular models of biological targets: virtual screening and de novo design, are presented. Examples of the above-listed approaches for the simulation of a number of pharmacologically significant receptors, analysis of receptor-ligand interactions and design of new biologically active organic compounds are given.

  2. How active ingredient localisation in plant tissues determines the targeted pest spectrum of different chemistries

    DEFF Research Database (Denmark)

    Buchholz, Anke; Trapp, Stefan

    2016-01-01

    information sets revealed that the intracellular localisation of active ingredients determines the performance of test compounds against different target pests because of different feeding behaviours: mites feed on mesophyll, and aphids and whiteflies mostly in the vascular system. Polar compounds have a slow...... adsorption into leaf cells and thus a favourable distribution into apoplast and xylem sap. Slightly lipophilic bases get trapped in vacuoles, which is a less suited place to control hemipteran pests but appropriate to control mites. Non-favourable cellular localisation led to a strong reduction...

  3. Chemistry and Biological Activities of Essential Oils from Melaleuca L. Species

    Directory of Open Access Journals (Sweden)

    Luiz Claudio Almeida Barbosa

    2013-03-01

    Full Text Available Essential oils from species Melaleuca genus, especially M. alternifolia (Maiden & Betche Cheel, have been widely used worldwide in various industries. This review is a contribution to Melaleuca knowledge and describes five important essential oil-producing species and two subspecies of Melaleuca in terms of their essential oil chemical composition, medicinal applications, and leaf morphoanatomy. Some relationships between essential oil composition of these species and important biological activities are presented. Useful parameters for the certification of the essential oils are also highlighted.

  4. Chemistry, cytotoxicity and antileishmanial activity of the essential oil from Piper auritum

    Directory of Open Access Journals (Sweden)

    Lianet Monzote

    2010-03-01

    Full Text Available Leishmaniasis is one of the most important parasitic infections, but current treatments are unsatisfactory due to their toxicity, cost and resistance. Therefore, the development of new antileishmanial compounds is imperative. Many people who live in endemic areas use plants as an alternative to treat the disease. In this paper, we characterised the essential oil from Piper auritum, evaluated its cytotoxicity and determined its antileishmanial activity. The chromatogram obtained by gas chromatography revealed 60 peaks and we found that safrole was the most abundant compound, composing 87% of the oil. The oil was active against the promastigotes of Leishmania major, Leishmania mexicana, Leishmania braziliensis and Leishmania donovani with a favourable selectivity index against peritoneal macrophages from BALB/c mice. The Piper-oil inhibited the growing of intracellular amastigotes of L. donovani with an IC50 value of 22.3 ± 1.8 μg/mL. This study demonstrates the usefulness of the essential oils as a promising alternative to treat leishmaniasis.

  5. Atmospheric Chemistry Measurements in Schools and Outreach Activities with Low-cost Air Quality Sensors

    Science.gov (United States)

    Fleming, Z.; Monks, P. S.; McKenzie, K.

    2014-12-01

    The increasing range of low cost air quality sensors entering the market-place or being developed in-house in the last couple of years has led to many possibilities for using these instruments for public outreach activities or citizen science projects. A range of instruments sent out into local schools for the children to interpret and analyse the data and put the air quality in their area into context. A teaching package with tutorials has been developed to bring the data to life and link in with curriculum.The instruments have also been positioned around the city of Leicester in the UK to help understand the spatial variations in air quality and to assess the impact of retro-fitting buses on a busy bus route. The data is easily accessible online on a near real time basis and the various instruments can be compared with others around the country or the world from classrooms around the world.We will give an overview of the instrumentation with a comparison with commercial and cutting edge research instrumentation, the type of activities that were carried out and the public outreach forums where the data can be used.

  6. Collaborative activities for solving multi-step problems in general chemistry

    Directory of Open Access Journals (Sweden)

    Luis Antonio Tortajada-Genaro

    2014-12-01

    Full Text Available The learning of solving multi-step problems is a relevant objective in chemical education for engineering students. In these questions, after analyzing initial data, a complex reasoning and an elaborated mathematical procedure is needed to achieve the correct numerical answer. But, many students are able to effectively use algorithms even with a lack of meaningful understanding of involved chemical concepts. This paper reports the application of some collaborative actions in order to induce a complete acquisition of problem solving skills. The studied approaches, performed inside and outside the classroom, are classified in low-collaborative and high-collaborative activities depending on the relative participation of instructor/students in their development. The critical description of proposed methodology and the produced outcomes are exposed. The contribution of each major reasoning mode (model, rule or case based employed in these activities is analyzed. Also, the perception of students is evaluated based on the data provided by direct observation and a specific survey with Likert-scale and open-ended questions. The results indicate that the changes of teaching to a more conceptual orientation lead a deeper understanding, minimizing misconceptions or a rote learning.

  7. Chemistry and in vitro antioxidant activity of volatile oil and oleoresins of black pepper (Piper nigrum).

    Science.gov (United States)

    Kapoor, I P S; Singh, Bandana; Singh, Gurdip; De Heluani, Carola S; De Lampasona, M P; Catalan, Cesar A N

    2009-06-24

    Essential oil and oleoresins (ethanol and ethyl acetate) of Piper nigrum were extracted by using Clevenger and Soxhlet apparatus, respectively. GC-MS analysis of pepper essential oil showed the presence of 54 components representing about 96.6% of the total weight. beta-Caryophylline (29.9%) was found as the major component along with limonene (13.2%), beta-pinene (7.9%), sabinene (5.9%), and several other minor components. The major component of both ethanol and ethyl acetate oleoresins was found to contain piperine (63.9 and 39.0%), with many other components in lesser amounts. The antioxidant activities of essential oil and oleoresins were evaluated against mustard oil by peroxide, p-anisidine, and thiobarbituric acid. Both the oil and oleoresins showed strong antioxidant activity in comparison with butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) but lower than that of propyl gallate (PG). In addition, their inhibitory action by FTC method, scavenging capacity by DPPH (2,2'-diphenyl-1-picrylhydrazyl radical), and reducing power were also determined, proving the strong antioxidant capacity of both the essential oil and oleoresins of pepper.

  8. Chemistry of ash-leachates to monitor volcanic activity: An application to Popocatepetl volcano, central Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Armienta, M.A., E-mail: victoria@geofisica.unam.mx [Universidad Nacional Autonoma de Mexico, Instituto de Geofisica, Circuito Exterior, C.U., Mexico 04510 D.F. (Mexico); De la Cruz-Reyna, S. [Universidad Nacional Autonoma de Mexico, Instituto de Geofisica, Circuito Exterior, C.U., Mexico 04510 D.F. (Mexico); Soler, A. [Grup de Mineralogia Aplicada i Medi Ambient, Dep. Cristal.lografia, Mineralogia i Diposits Minerals, Fac. Geologia, Universidad de Barcelona (Spain); Cruz, O.; Ceniceros, N.; Aguayo, A. [Universidad Nacional Autonoma de Mexico, Instituto de Geofisica, Circuito Exterior, C.U., Mexico 04510 D.F. (Mexico)

    2010-08-15

    Monitoring volcanic activity and assessing volcanic risk in an on-going eruption is a problem that requires the maximum possible independent data to reduce uncertainty. A quick, relatively simple and inexpensive method to follow the development of an eruption and to complement other monitoring parameters is the chemical analysis of ash leachates, particularly in the case of eruptions related to dome emplacement. Here, the systematic analysis of SO{sub 4}{sup 2-}, Cl{sup -} and F{sup -} concentrations in ash leachates is proposed as a valuable tool for volcanic activity monitoring. However, some results must be carefully assessed, as is the case for S/Cl ratios, since eruption of hydrothermally altered material may be confused with degassing of incoming magma. Sulfur isotopes help to identify SO{sub 4} produced by hydrothermal processes from magmatic SO{sub 2}. Lower S isotopic values correlated with higher F{sup -} percentages represent a better indicator of fresh magmatic influence that may lead to stronger eruptions and emplacement of new lava domes. Additionally, multivariate statistical analysis helps to identify different eruption characteristics, provided that the analyses are made over a long enough time to sample different stages of an eruption.

  9. Photography by Cameras Integrated in Smartphones as a Tool for Analytical Chemistry Represented by an Butyrylcholinesterase Activity Assay.

    Science.gov (United States)

    Pohanka, Miroslav

    2015-06-11

    Smartphones are popular devices frequently equipped with sensitive sensors and great computational ability. Despite the widespread availability of smartphones, practical uses in analytical chemistry are limited, though some papers have proposed promising applications. In the present paper, a smartphone is used as a tool for the determination of cholinesterasemia i.e., the determination of a biochemical marker butyrylcholinesterase (BChE). The work should demonstrate suitability of a smartphone-integrated camera for analytical purposes. Paper strips soaked with indoxylacetate were used for the determination of BChE activity, while the standard Ellman's assay was used as a reference measurement. In the smartphone-based assay, BChE converted indoxylacetate to indigo blue and coloration was photographed using the phone's integrated camera. A RGB color model was analyzed and color values for the individual color channels were determined. The assay was verified using plasma samples and samples containing pure BChE, and validated using Ellmans's assay. The smartphone assay was proved to be reliable and applicable for routine diagnoses where BChE serves as a marker (liver function tests; some poisonings, etc.). It can be concluded that the assay is expected to be of practical applicability because of the results' relevance.

  10. Photography by Cameras Integrated in Smartphones as a Tool for Analytical Chemistry Represented by an Butyrylcholinesterase Activity Assay

    Directory of Open Access Journals (Sweden)

    Miroslav Pohanka

    2015-06-01

    Full Text Available Smartphones are popular devices frequently equipped with sensitive sensors and great computational ability. Despite the widespread availability of smartphones, practical uses in analytical chemistry are limited, though some papers have proposed promising applications. In the present paper, a smartphone is used as a tool for the determination of cholinesterasemia i.e., the determination of a biochemical marker butyrylcholinesterase (BChE. The work should demonstrate suitability of a smartphone-integrated camera for analytical purposes. Paper strips soaked with indoxylacetate were used for the determination of BChE activity, while the standard Ellman’s assay was used as a reference measurement. In the smartphone-based assay, BChE converted indoxylacetate to indigo blue and coloration was photographed using the phone’s integrated camera. A RGB color model was analyzed and color values for the individual color channels were determined. The assay was verified using plasma samples and samples containing pure BChE, and validated using Ellmans’s assay. The smartphone assay was proved to be reliable and applicable for routine diagnoses where BChE serves as a marker (liver function tests; some poisonings, etc.. It can be concluded that the assay is expected to be of practical applicability because of the results’ relevance.

  11. Active transport, ion movements, and pH changes : I. The chemistry of pH changes.

    Science.gov (United States)

    Good, N E

    1988-10-01

    The transport of substances across cell membranes may be the most fundamental activity of living things. When the substance transported is any ion there can be a change in the concentration of hydrogen ions on the two sides of the membrane. These hydrogen ion concentration changes are not caused by fluxes of hydrogen ions although fluxes of hydrogen ions may sometimes be involved. The reason for the apparent contradiction is quite simple. All aqueous systems are subject to two constraints: (1) to maintain the charge balance, the sum of the cationic charges must equal the sum of the anionic charges and (2) the product of the molar concentration of H(+) and the molar concentration of OH(-), established and maintained by the association and the dissociation of water, remains always at 10(-14). As a consequence the concentrations of H(+) and OH(-) are determined uniquely by differences between the concentrations of the other cations and anions, with [H(+)] and [OH(-)] being dependent variables. Hydrogen ions and hydroxyl ions can be produced or consumed in local reactions whereas any strong ions such as Cl(-), Mg(2+), or K(+) can be neither produced nor consumed in biological reactions. Further consequences of these truisms are outlined here in terms of the chemistry of the kinds of reactions which can lead to pH changes.

  12. Green chemistry focus on optimization of silver nanoparticles using response surface methodology (RSM) and mosquitocidal activity: Anopheles stephensi (Diptera: Culicidae).

    Science.gov (United States)

    Ondari Nyakundi, Erick; Padmanabhan, M Nalini

    2015-01-01

    There is an exigent necessity for development of environmental friendly bio-control agent(s) for elimination of mosquito due to increased resistance resurgence against synthetic control agents. Mosquito control strategy will lay a strong foundation to malaria exclusion or it can be curbed to certain level especially in the developing nations. In this study, silver nanoparticles were synthesized by green chemistry approach using Tridax procumbens leaf extract as a reducing agent. The reaction medium involved in the synthesis process was optimized by statistical experimental design using response surface methodology to obtain better yield, uniform size, shape and stability. Further, these synthesized nanoparticles were confirmed through UV-Visible, FT-IR spectroscopy, PSA and SEM Subsequently, the bioefficacy of these particles were investigated on Anopheles stephensi for larvicidal and pupicidal activity. Interestingly, time period of 90 min, temperature of 76±2 °C, pH 7.2±2, 2 mM silver nitrate (AgNO3), 3mM PEG and 2mM PVP showed excellent parameters for bioprocess design for large scale production of stabilized nanoparticles. A concentration of 5 ppm of PVP stabilized nanoparticles exhibited 100% mortality. Thus, the obtained results clearly suggest that silver nanoparticles stabilized by PEG and PVP may have important function as stabilizers, dispersants as well as larvicides for mosquito control.

  13. Conformation-activity studies on the interaction of berberine with acetylcholinesterase:Physical chemistry approach

    Institute of Scientific and Technical Information of China (English)

    Jin Xiang; Changping Yu; Fang Yang; Ling Yang; Hong Ding

    2009-01-01

    Berberine has been reported as an acetylcholinesterase (AChE) inhibitor.With significantly low cytotoxicity,berberine will be developed for the clinical treatment of Alzheimer disease (AD) with higher efficacy and fewer side effects.This work investigated the structure change events of AChE that occur during the interaction with berberine by isothermal titration calorimetry (ITC),fluorescence titration,and circular dichroism (CD).The results show that the binding of berberine to AChE is mainly driven by a favorable entropy increase with a less weak affinity.Berberine causes a loss in enzymatic activity at a concentration much below the concentration which gradually exposed the tryptophan residues to a more hydrophilic environment and unfolded the protein,which indicates that the inhibition of AChE with berberine includes the main contributions of interaction and minor conformation change of the protein induced by the alkaloid.

  14. A review of chemistry and biological activities of the genus Aerva--a desert plant.

    Science.gov (United States)

    Chawla, Payal; Chawla, Amit; Vasudeva, Neeru; Sharma, Surendra Kumar

    2012-01-01

    There are approximately 28 species of Aerva genus, but only a few species are medicinal of which A. persica, A. lanata and A. javanica are of great value. A number of flavonol glycosides (e.g., aervanone, kaempferol-3-galactoside, isorhamnetin-3-O-β-D-glucoside) have been reported from Aerva persica as major phytoconstituents and the minor constituents are β-cyanins (glycine betaine and trigonelline), sterols and carbohydrates. This plant is used as medicinal herb in several traditional systems of medicine all over the world, like diuretic, demulcent, purgative, emetic and tinder. Aerva plants are used to cure ulcer, lithiasis, dropsical affections, eye affection, toothache, headache, in disorders of abdomen and inflammation of internal organs. Roots and flowers are reported to possess hypoglycemic, antioxidant, anthelmintic, analgesic, antimalarial, antivenin activities and medicinal properties against rheumatism and kidney troubles.

  15. Layered Double Hydroxide Nanoclusters: Aqueous, Concentrated, Stable, and Catalytically Active Colloids toward Green Chemistry.

    Science.gov (United States)

    Tokudome, Yasuaki; Morimoto, Tsuyoshi; Tarutani, Naoki; Vaz, Pedro D; Nunes, Carla D; Prevot, Vanessa; Stenning, Gavin B G; Takahashi, Masahide

    2016-05-24

    Increasing attention has been dedicated to the development of nanomaterials rendering green and sustainable processes, which occur in benign aqueous reaction media. Herein, we demonstrate the synthesis of another family of green nanomaterials, layered double hydroxide (LDH) nanoclusters, which are concentrated (98.7 g/L in aqueous solvent), stably dispersed (transparent sol for >2 weeks), and catalytically active colloids of nano LDHs (isotropic shape with the size of 7.8 nm as determined by small-angle X-ray scattering). LDH nanoclusters are available as colloidal building blocks to give access to meso- and macroporous LDH materials. Proof-of-concept applications revealed that the LDH nanocluster works as a solid basic catalyst and is separable from solvents of catalytic reactions, confirming the nature of nanocatalysts. The present work closely investigates the unique physical and chemical features of this colloid, the formation mechanism, and the ability to act as basic nanocatalysts in benign aqueous reaction systems.

  16. Role of surface chemistry in modified ACF (activated carbon fiber)-catalyzed peroxymonosulfate oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shiying, E-mail: ysy@ouc.edu.cn [Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100 (China); College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100 (China); Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering (MEGE), Qingdao 266100 (China); Li, Lei [College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100 (China); Xiao, Tuo [College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100 (China); China City Environment Protection Engineering Limited Company, Wuhan 430071 (China); Zheng, Di; Zhang, Yitao [College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100 (China)

    2016-10-15

    Highlights: • ACF can efficiently activate peroxymonosulfate to degrade organic pollutants. • Basic functional groups may mainly increase the adsorption capacity of ACF. • C1, N1, N2 have promoting effect on the ACF catalyzed PMS oxidation. • Modification by heat after nitric acid is also a way of ACF regeneration. - Abstract: A commercial activated carbon fiber (ACF-0) was modified by three different methods: nitration treatment (ACF-N), heat treatment (ACF-H) and heat treatment after nitration (ACF-NH), and the effects of textural and chemical properties on the ability of the metal-free ACF-catalyzed peroxymonosulfate (PMS) oxidation of Reactive Black 5 (RB5), an azo dye being difficultly adsorbed onto ACF, in aqueous solution were investigated in this work. Surface density of functional groups, surface area changes, surface morphology and the chemical state inside ACF samples were characterized by Boehm titration, N{sub 2} adsorption, scanning electron microscopy in couple with energy dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS), respectively. XPS spectra deconvolution was applied to figure out the importance of surface nitrogen-containing function groups. We found that π-π, pyridine and amine have promoting effect on the catalytic oxidation while the −NO{sub 2} has inhibitory effect on the ACF/PMS systems for RB5 destroy. Sustainability and renewability of the typical ACF-NH for catalytic oxidation of RB5 were also discussed in detail. Information about our conclusions are useful to control and improve the performance of ACF-catalyzed PMS oxidation for organic pollutants in wastewater treatment.

  17. Annual Report 1984. Chemistry Department

    DEFF Research Database (Denmark)

    Funck, Jytte; Nielsen, Ole John

    This report contains a brief survey of the main activities in the Chemistry Department. All articles and reports published and lectures given in 1984 are presented. The facilities and equipment are mentioned briefly. The activities are divided into the following groups: radioisotope chemistry...

  18. Role of surface chemistry in modified ACF (activated carbon fiber)-catalyzed peroxymonosulfate oxidation

    Science.gov (United States)

    Yang, Shiying; Li, Lei; Xiao, Tuo; Zheng, Di; Zhang, Yitao

    2016-10-01

    A commercial activated carbon fiber (ACF-0) was modified by three different methods: nitration treatment (ACF-N), heat treatment (ACF-H) and heat treatment after nitration (ACF-NH), and the effects of textural and chemical properties on the ability of the metal-free ACF-catalyzed peroxymonosulfate (PMS) oxidation of Reactive Black 5 (RB5), an azo dye being difficultly adsorbed onto ACF, in aqueous solution were investigated in this work. Surface density of functional groups, surface area changes, surface morphology and the chemical state inside ACF samples were characterized by Boehm titration, N2 adsorption, scanning electron microscopy in couple with energy dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS), respectively. XPS spectra deconvolution was applied to figure out the importance of surface nitrogen-containing function groups. We found that π-π, pyridine and amine have promoting effect on the catalytic oxidation while the -NO2 has inhibitory effect on the ACF/PMS systems for RB5 destroy. Sustainability and renewability of the typical ACF-NH for catalytic oxidation of RB5 were also discussed in detail. Information about our conclusions are useful to control and improve the performance of ACF-catalyzed PMS oxidation for organic pollutants in wastewater treatment.

  19. Assessing the Protective Activity of a Recently Discovered Phenolic Compound against Oxidative Stress Using Computational Chemistry.

    Science.gov (United States)

    Villuendas-Rey, Yenny; Alvarez-Idaboy, Juan Raul; Galano, Annia

    2015-12-28

    The protection exerted by 3,5-dihydroxy-4-methoxybenzyl alcohol (DHMBA), a phenolic compound recently isolated from the Pacific oyster, against oxidative stress (OS) is investigated using the density functional theory. Our results indicate that DHMBA is an outstanding peroxyl radical scavenger, being about 15 times and 4 orders of magnitude better than Trolox for that purpose in lipid and aqueous media, respectively. It was also found to react faster with HOO(•) than other known antioxidants such as resveratrol and ascorbic acid. DHMBA is also predicted to be able to sequester Cu(II) ions, consequently inhibiting the OS induced by Cu(II)-ascorbate mixtures and downgrading the (•)OH production via the Haber-Weiss reaction. However, it is proposed that DHMBA is more efficient as a primary antioxidant (free radical scavenger), than as a secondary antioxidant (metal ion chelator). In addition, it was found that DHMBA can be efficiently regenerated in aqueous solution, at physiological pH. Such regeneration is expected to contribute to increase the antioxidant protection exerted by DHMBA. These results suggest that probably synthetic routes for this compound should be pursued, because albeit its abundance in nature is rather low, its antioxidant activity is exceptional.

  20. Coriander(Coriandrum sativum L.) essential oil: chemistry and biological activity

    Institute of Scientific and Technical Information of China (English)

    Shyamapada; Mandal; Manisha; Mandal

    2015-01-01

    Coriandrum sativum L.(C. sativum) is one of the most useful essential oil bearing spices as well as medicinal plants, belonging to the family Umbelliferae/Apiaceae. The leaves and seeds of the plant are widely used in folk medicine in addition to its use as a seasoning in food preparation. The C. sativum essential oil and extracts possess promising antibacterial, antifungal and anti-oxidative activities as various chemical components in dif erent parts of the plant, which thus play a great role in maintaining the shelf-life of foods by preventing their spoilage. This edible plant is non-toxic to humans, and the C. sativum essential oil is thus used in dif erent ways, viz., in foods(like l avoring and preservatives) and in pharmaceutical products(therapeutic action) as well as in perfumes(fragancias and lotions). The current updates on the usefulness of the plant C. sativum are due to scientii c research published in dif erent web-based journals.

  1. Mutagenesis of the redox-active disulfide in mercuric ion reductase: Catalysis by mutant enzymes restricted to flavin redox chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Distefano, M.D.; Au, K.G.; Walsh, C.T. (Harvard Medical School, Boston, MA (USA))

    1989-02-07

    Mercuric reductase, a flavoenzyme that possesses a redox-active cystine, Cys{sub 135}Cys{sub 140}, catalyzes the reduction of Hg(II) to Hg(0) by NADPH. As a probe of mechanism, the authors have constructed mutants lacking a redox-active disulfide by eliminating Cys{sub 135} (Ala{sub 135}Cys{sub 140}), Cys{sub 14} (Cys{sub 135}Ala{sub 140}), or both (Ala{sub 135}Ala{sub 140}). Additionally, they have made double mutants that lack Cys{sub 135} (Ala{sub 135}Cys{sub 139}Cys{sub 140}) or Cys{sub 140} (Cys{sub 135}Cys{sub 139}Ala{sub 140}) but introduce a new Cys in place of Gly{sub 139} with the aim of constructing dithiol pairs in the active site that do not form a redox-active disulfide. The resulting mutant enzymes all lack redox-active disulfides and are hence restricted to FAD/FADH{sub 2} redox chemistry. Each mutant enzyme possesses unique physical and spectroscopic properties that reflect subtle differences in the FAD microenvironment. Preliminary evidence for the Ala{sub 135}Cys{sub 139}Cys{sub 14} mutant enzyme suggests that this protein forms a disulfide between the two adjacent Cys residues. Hg(II) titration experiments that correlate the extent of charge-transfer quenching with Hg(II) binding indicate that the Ala{sub 135}Cys{sub 140} protein binds Hg(II) with substantially less avidity than does the wild-type enzyme. All mutant mercuric reductases catalyze transhydrogenation and oxygen reduction reactions through obligatory reduced flavin intermediates at rates comparable to or greater than that of the wild-type enzyme. In multiple-turnover assays which monitored the production of Hg(0), two of the mutant enzymes were observed to proceed through at least 30 turnovers at rates ca. 1000-fold slower than that of wild-type mercuric reductase. They conclude that the Cys{sub 135} and Cys{sub 140} thiols serve as Hg(II) ligands that orient the Hg(II) for subsequent reduction by a reduced flavin intermediate.

  2. Sampling and major element chemistry of the recent (A.D. 1631-1944) Vesuvius activity

    Science.gov (United States)

    Belkin, H.E.; Kilburn, C.R.J.; de Vivo, B.

    1993-01-01

    Detailed sampling of the Vesuvius lavas erupted in the period A.D. 1631-1944 provides a suite of samples for comprehensive chemical analyses and related studies. Major elements (Si, Ti, Al, Fetotal, Mn, Mg, Ca, Na, K and P), volatile species (Cl, F, S, H2O+, H2O- and CO2), and ferrous iron (Fe2+) were determined for one hundred and forty-nine lavas and five tephra from the A.D. 1631-1944 Vesuvius activity. The lavas represent a relatively homogeneous suite with respect to SiO2, TiO2, FeOtotal, MnO and P2O5, but show systematic variations among MgO, K2O, Na2O, Al2O3 and CaO. The average SiO2 content is 48.0 wt.% and the rocks are classified as tephriphonolites according to their content of alkalis. All of the lavas are silica-undersaturated and are nepheline, leucite, and olivine normative. There is no systematic variation in major-element composition with time, over the period A.D. 1631-1944. The inter-eruption and intra-eruption compositional differences are the same magnitude. The lavas are highly porphyritic with clinopyroxene and leucite as the major phases. Fractionation effects are not reflected in the silica content of the lavas. The variability of MgO, K2O, Na2O, and CaO can be modelled as a relative depletion or accumulation of clinopyroxene. ?? 1993.

  3. Alkali-activated fly ash. Relationship between mechanical strength gains and initial ash chemistry

    Directory of Open Access Journals (Sweden)

    Palomo, A.

    2008-09-01

    Full Text Available Alkali-activated fly ash is the primary component of a new generation of high-strength, durable binders with excellent mechanical properties and durability (on occasion bettering traditional Portland cement performance. Moreover, development of these cements may contribute to mitigating CO2 emissions, since the base material is an industrial by-product. The present study was conducted to determine the effect of the composition of the initial materials (SiO2/Al2O3 and Na2O/Al2O3 ratios on the mechanical properties, nature and composition of the reaction products. The results obtained indicate that there is no linear relationship between these ratios and mechanical strength, but rather a series of optimal values above and below which strength declines. In the specific case of the ratios studied in the present paper, these values were: SiO2/Al2O3= 4.0 and Na2O/Al2O3= 1.0 (molar ratios.Las cenizas volantes activadas alcalinamente constituyen la base de una nueva generación de cementos con muy interesantes propiedades mecánicas, adherentes y durables (a veces incluso mejores que las de los cementos Portland tradicionales. Adicionalmente el desarrollo de estos cementos podría contribuir a mitigar las emisiones de CO2 a la atmósfera, ya que el material base de los mismos puede estar formado por subproductos industriales. En la presente investigación se realizó un estudio para determinar la influencia de la composición de los materiales iniciales (ratios SiO2/Al2O3 y Na2O/Al2O3 en las propiedades mecánicas y en la naturaleza y composición de los productos de reacción. Los resultados obtenidos indican que no existe una relación lineal de dichas ratios con las resistencias mecánicas, sino que existen unos valores óptimos, por encima y debajo de los cuales las resistencias mecánicas disminuyen. En el caso concreto de las ratios estudiadas en el presente trabajo estos valores serian: SiO2/Al2O3= 4,0 y Na2O/Al2O3= 1,0 (relaciones molares

  4. Quantum chemistry

    CERN Document Server

    Lowe, John P

    1993-01-01

    Praised for its appealing writing style and clear pedagogy, Lowe's Quantum Chemistry is now available in its Second Edition as a text for senior undergraduate- and graduate-level chemistry students. The book assumes little mathematical or physical sophistication and emphasizes an understanding of the techniques and results of quantum chemistry, thus enabling students to comprehend much of the current chemical literature in which quantum chemical methods or concepts are used as tools. The book begins with a six-chapter introduction of standard one-dimensional systems, the hydrogen atom,

  5. Get Cooking with Chemistry!

    Science.gov (United States)

    American Chemical Society, Washington, DC.

    This book presents science activities investigating the chemical changes and reactions with powders that are used in baking. Activities include: (1) Mystery Powders; (2) Find the Fizz: Discover the Secret of Baking Powder; and (3) A Feast for Yeast and Cheese: Behold the Power of Chemistry. (YDS)

  6. Chemistry of phosphorus ylides 31: Reaction of azidocoumarin with active phosphonium ylides, synthesis and antitumour activities of chromenones

    Indian Academy of Sciences (India)

    Soher S Maigali; Mansoura A Abd-El-Maksoud; Fouad M Soliman

    2013-11-01

    The reaction of 4- azidochromen-2-one (1) with the nucleophilic phosphacumulene ylides 2, 8, and 12 afforded the new heterocyclic triazoles, triazepines, aziridine, pyrrolone containing a coumarin moiety. Cycloaddition reactions took place first to give triazoline 3 and 9. The triazolines rearranged to the triazepines 4, 10, and 13 accompanied by elimination of triphenylphosphine leading to the phosphorus-free triazepines 5, 11, and moreover, aziridine 6 was produced via nitrogen extrusion from the triazoline 3, followed by ring expansion to the pyrrolone 7. On the other hand, the reaction of the azidocoumarin 1 with the phosphallene yield 15 behaves differently and afforded the triazine 17 and azetone 18. The antitumour activity of compounds 3, 4, 6, and 11 was evaluated, in vitro, against (breast: MCF-7 and liver: HPEG2) human solid tumour cell lines. They showed values closed to that recorded by the reference drug doxorubicin.

  7. Introductory Chemistry

    OpenAIRE

    Baron, Mark; Gonzalez-Rodriguez, Jose; Stevens, Gary; Gray, Nathan; Atherton, Thomas; Winn, Joss

    2010-01-01

    Teaching and Learning resources for the 1st Year Introductory Chemistry course (Forensic Science). 30 credits. These are Open Educational Resources (OER), made available for re-use under a Creative Commons license.

  8. Materials Chemistry

    CERN Document Server

    Fahlman, Bradley D

    2011-01-01

    The 2nd edition of Materials Chemistry builds on the strengths that were recognized by a 2008 Textbook Excellence Award from the Text and Academic Authors Association (TAA). Materials Chemistry addresses inorganic-, organic-, and nano-based materials from a structure vs. property treatment, providing a suitable breadth and depth coverage of the rapidly evolving materials field. The 2nd edition continues to offer innovative coverage and practical perspective throughout. After briefly defining materials chemistry and its history, seven chapters discuss solid-state chemistry, metals, semiconducting materials, organic "soft" materials, nanomaterials, and materials characterization. All chapters have been thoroughly updated and expanded with, for example, new sections on ‘soft lithographic’ patterning, ‘click chemistry’ polymerization, nanotoxicity, graphene, as well as many biomaterials applications. The polymer and ‘soft’ materials chapter represents the largest expansion for the 2nd edition. Each ch...

  9. Cluster Chemistry

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ Cansisting of eight scientists from the State Key Laboratory of Physical Chemistry of Solid Surfaces and Xiamen University, this creative research group is devoted to the research of cluster chemistry and creation of nanomaterials.After three-year hard work, the group scored a series of encouraging progresses in synthesis of clusters with special structures, including novel fullerenes, fullerene-like metal cluster compounds as well as other related nanomaterials, and their properties study.

  10. Green Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Collison, Melanie

    2011-05-15

    Green chemistry is the science of chemistry used in a way that will not use or create hazardous substances. Dr. Rui Resendes is working in this field at GreenCentre Canada, an offshoot of PARTEQ Innovations in Kingston, Ontario. GreenCentre's preliminary findings suggest their licensed product {sup S}witchable Solutions{sup ,} featuring 3 classes of solvents and a surfactant, may be useful in bitumen oil sands extraction.

  11. Art in Chemistry: Chemistry in Art. Second Edition

    Science.gov (United States)

    Greenberg, Barbara R.; Patterson, Dianne

    2008-01-01

    This textbook integrates chemistry and art with hands-on activities and fascinating demonstrations that enable students to see and understand how the science of chemistry is involved in the creation of art. It investigates such topics as color integrated with electromagnetic radiation, atoms, and ions; paints integrated with classes of matter,…

  12. Art in Chemistry: Chemistry in Art. Second Edition

    Science.gov (United States)

    Greenberg, Barbara R.; Patterson, Dianne

    2008-01-01

    This textbook integrates chemistry and art with hands-on activities and fascinating demonstrations that enable students to see and understand how the science of chemistry is involved in the creation of art. It investigates such topics as color integrated with electromagnetic radiation, atoms, and ions; paints integrated with classes of matter,…

  13. Green Chemistry: Progress and Barriers

    Science.gov (United States)

    Green, Sarah A.

    2016-10-01

    Green chemistry can advance both the health of the environment and the primary objectives of the chemical enterprise: to understand the behavior of chemical substances and to use that knowledge to make useful substances. We expect chemical research and manufacturing to be done in a manner that preserves the health and safety of workers; green chemistry extends that expectation to encompass the health and safety of the planet. While green chemistry may currently be treated as an independent branch of research, it should, like safety, eventually become integral to all chemistry activities. While enormous progress has been made in shifting from "brown" to green chemistry, much more effort is needed to effect a sustainable economy. Implementation of new, greener paradigms in chemistry is slow because of lack of knowledge, ends-justify-the-means thinking, systems inertia, and lack of financial or policy incentives.

  14. Radiation Chemistry

    Science.gov (United States)

    Wojnárovits, L.

    Ionizing radiation causes chemical changes in the molecules of the interacting medium. The initial molecules change to new molecules, resulting in changes of the physical, chemical, and eventually biological properties of the material. For instance, water decomposes to its elements H2 and O2. In polymers, degradation and crosslinking take place. In biopolymers, e.g., DNS strand breaks and other alterations occur. Such changes are to be avoided in some cases (radiation protection), however, in other cases they are used for technological purposes (radiation processing). This chapter introduces radiation chemistry by discussing the sources of ionizing radiation (radionuclide sources, machine sources), absorption of radiation energy, techniques used in radiation chemistry research, and methods of absorbed energy (absorbed dose) measurements. Radiation chemistry of different classes of inorganic (water and aqueous solutions, inorganic solids, ionic liquids (ILs)) and organic substances (hydrocarbons, halogenated compounds, polymers, and biomolecules) is discussed in concise form together with theoretical and experimental backgrounds. An essential part of the chapter is the introduction of radiation processing technologies in the fields of polymer chemistry, food processing, and sterilization. The application of radiation chemistry to nuclear technology and to protection of environment (flue gas treatment, wastewater treatment) is also discussed.

  15. Design, synthesis and bioactivity of novel ALS enzyme inhibitors (II)——Molecular mechanics, quantum chemistry and structure-activity relationship studies on the herbicidal heterocyclic sulfonamide

    Institute of Scientific and Technical Information of China (English)

    陆荣健; 杨华铮; 尚贞锋; 汪惟为; 潘荫明; 赵学庄

    1996-01-01

    In view of quantum pharmacology, the structure-activity relationships of different kinds of fused heterocydic sulfonamides with the same mode of action were first investigated using molecular mechanics, quantum chemistry and discriminatory analysis. It has been found that the process of the interaction of the fused heterocydic sulfonamide with ALS enzyme involves the electropositive region of the sulfonyl bridge chain and the electronegative region of the heterocydic moiety. The herbicidal activity is related to the potency of electric charge translocation of the related regions.

  16. Using Undergraduate Facilitators for Active Learning in Organic Chemistry: A Preparation Course and Outcomes of the Experience

    Science.gov (United States)

    Jardine, Hannah E.; Friedman, Lee A.

    2017-01-01

    In this study, we describe a course to educate and prepare undergraduate "facilitators" for small group problem solving sessions in a large, first semester, introductory undergraduate organic chemistry course. We then explore the outcomes of the facilitator experience for one cohort of facilitators through qualitative analysis of written…

  17. Enhancing Student Performance in First-Semester General Chemistry Using Active Feedback through the World Wide Web

    Science.gov (United States)

    Chambers, Kent A.; Blake, Bob

    2007-01-01

    The World Wide Web recently launched a new interactive feedback system for the instructors, so that can better understanding about their students and their problems. The feedback, in combination with tailored lectures is expected to enhance student performance in the first semester of general chemistry.

  18. Using a Practical Instructional Development Process to Show That Integrating Lab and Active Learning Benefits Undergraduate Analytical Chemistry

    Science.gov (United States)

    Goacher, Robyn E.; Kline, Cynthia M.; Targus, Alexis; Vermette, Paul J.

    2017-01-01

    We describe how a practical instructional development process helped a first-year assistant professor rapidly develop, implement, and assess the impact on her Analytical Chemistry course caused by three changes: (a) moving the lab into the same semester as the lecture, (b) developing a more collaborative classroom environment, and (c) increasing…

  19. Synthesis and ligand-based reduction chemistry of boron difluoride complexes with redox-active formazanate ligands

    NARCIS (Netherlands)

    Chang, M. -C.; Otten, E.

    2014-01-01

    Mono(formazanate) boron difluoride complexes (LBF2), which show remarkably facile and reversible ligand-based redox-chemistry, were synthesized by transmetallation of bis(formazanate) zinc complexes with boron trifluoride. The one-electron reduction product [LBF2](-)[Cp2Co](+) and a key intermediate

  20. Switching activation barriers: new insights in E-field driven processes at the interface: perspectives in physical chemistry and catalysis

    NARCIS (Netherlands)

    Susarrey Arce, A.

    2014-01-01

    The research described in this thesis aimed to explore new concepts in catalysis with the use of a homemade ATR-IR silicon-based microreactor. During this journey we have performed multidisciplinary research at the interface between physics and chemistry. New insights in the fabrication, integration

  1. Impact of Active Teaching Methods Implemented on Therapeutic Chemistry Module: Performance and Impressions of First-Year Pharmacy Students

    Science.gov (United States)

    Derfoufi, Sanae; Benmoussa, Adnane; El Harti, Jaouad; Ramli, Youssef; Taoufik, Jamal; Chaouir, Souad

    2015-01-01

    This study investigates the positive impact of the Case Method implemented during a 4- hours tutorial in "therapeutic chemistry module." We view the Case Method as one particular approach within the broader spectrum of problem based or inquiry based learning approaches. Sixty students were included in data analysis. A pre-test and…

  2. Handbook of heterocyclic chemistry

    National Research Council Canada - National Science Library

    Katritzky, Alan R

    2010-01-01

    ... Heterocyclic Chemistry I (1984) Comprehensive Heterocyclic Chemistry II (1996) Comprehensive Heterocyclic Chemistry III (2008) Comprehensive Organic Functional Group Transformations I (1995) Compreh...

  3. Teacher Didactic Content Knowledge and its relation with the utilization of practical activities in chemistry classes: A study with expert teachers of the Angolan educational system

    Directory of Open Access Journals (Sweden)

    Laurinda Baca

    2014-03-01

    Full Text Available This study was developed within the Angolan educational system, with chemistry expert teachers who teach the 7th grade (12 years old. Aiming to characterize the didactic content knowledge and relate it with the quality of teaching and with the development of practical activities that ensure the active participation of students in the construction of knowledge, we observed and analyzed the classes of a group of expert teachers, specifically in the content of chemical reactions and chemical equations. In a quasi-experimental design methodology, the used technique was the observation from the capture of images in the classes. An element we paid particular attention in the analysis of the classes was the implementation of strategies that involve practical activities, since the didactic research has amply demonstrated that they are likely to generate active learning in science education, with particular emphasis in chemistry. The results revealed that the expert teachers often use practical activities in their classrooms, using group work procedures, work front and questions oral and written.

  4. Polymer Chemistry

    Science.gov (United States)

    Williams, Martha; Roberson, Luke; Caraccio, Anne

    2010-01-01

    This viewgraph presentation describes new technologies in polymer and material chemistry that benefits NASA programs and missions. The topics include: 1) What are Polymers?; 2) History of Polymer Chemistry; 3) Composites/Materials Development at KSC; 4) Why Wiring; 5) Next Generation Wiring Materials; 6) Wire System Materials and Integration; 7) Self-Healing Wire Repair; 8) Smart Wiring Summary; 9) Fire and Polymers; 10) Aerogel Technology; 11) Aerogel Composites; 12) Aerogels for Oil Remediation; 13) KSC's Solution; 14) Chemochromic Hydrogen Sensors; 15) STS-130 and 131 Operations; 16) HyperPigment; 17) Antimicrobial Materials; 18) Conductive Inks Formulations for Multiple Applications; and 19) Testing and Processing Equipment.

  5. Computational chemistry at Janssen.

    Science.gov (United States)

    van Vlijmen, Herman; Desjarlais, Renee L; Mirzadegan, Tara

    2016-12-19

    Computer-aided drug discovery activities at Janssen are carried out by scientists in the Computational Chemistry group of the Discovery Sciences organization. This perspective gives an overview of the organizational and operational structure, the science, internal and external collaborations, and the impact of the group on Drug Discovery at Janssen.

  6. Computational chemistry at Janssen

    Science.gov (United States)

    van Vlijmen, Herman; Desjarlais, Renee L.; Mirzadegan, Tara

    2016-12-01

    Computer-aided drug discovery activities at Janssen are carried out by scientists in the Computational Chemistry group of the Discovery Sciences organization. This perspective gives an overview of the organizational and operational structure, the science, internal and external collaborations, and the impact of the group on Drug Discovery at Janssen.

  7. Nuclear analytical chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Brune, D.; Forkman, B.; Persson, B.

    1984-01-01

    This book covers the general theories and techniques of nuclear chemical analysis, directed at applications in analytical chemistry, nuclear medicine, radiophysics, agriculture, environmental sciences, geological exploration, industrial process control, etc. The main principles of nuclear physics and nuclear detection on which the analysis is based are briefly outlined. An attempt is made to emphasise the fundamentals of activation analysis, detection and activation methods, as well as their applications. The book provides guidance in analytical chemistry, agriculture, environmental and biomedical sciences, etc. The contents include: the nuclear periodic system; nuclear decay; nuclear reactions; nuclear radiation sources; interaction of radiation with matter; principles of radiation detectors; nuclear electronics; statistical methods and spectral analysis; methods of radiation detection; neutron activation analysis; charged particle activation analysis; photon activation analysis; sample preparation and chemical separation; nuclear chemical analysis in biological and medical research; the use of nuclear chemical analysis in the field of criminology; nuclear chemical analysis in environmental sciences, geology and mineral exploration; and radiation protection.

  8. Shape-selective catalysts for Fischer-Tropsch chemistry : atomic layer deposition of active catalytic metals. Activity report : January 1, 2005 - September 30, 2005.

    Energy Technology Data Exchange (ETDEWEB)

    Cronauer, D. C. (Chemical Sciences and Engineering Division)

    2011-04-15

    Argonne National Laboratory is carrying out a research program to create, prepare, and evaluate catalysts to promote Fischer-Tropsch (FT) chemistry - specifically, the reaction of hydrogen with carbon monoxide to form long-chain hydrocarbons. In addition to needing high activity, it is desirable that the catalysts have high selectivity and stability with respect to both mechanical strength and aging properties. The broad goal is to produce diesel fraction components and avoiding excess yields of both light hydrocarbons and heavy waxes. Originally the goal was to prepare shape-selective catalysts that would limit the formation of long-chain products and yet retain the active metal sites in a protected 'cage.' Such catalysts were prepared with silica-containing fractal cages. The activity was essentially the same as that of catalysts without the cages. We are currently awaiting follow-up experiments to determine the attrition strength of these catalysts. A second experimental stage was undertaken to prepare and evaluate active FT catalysts formed by atomic-layer deposition [ALD] of active components on supported membranes and particulate supports. The concept was that of depositing active metals (i.e. ruthenium, iron or cobalt) upon membranes with well defined flow channels of small diameter and length such that the catalytic activity and product molecular weight distribution could be controlled. In order to rapidly evaluate the catalytic membranes, the ALD coating processes were performed in an 'exploratory mode' in which ALD procedures from the literature appropriate for coating flat surfaces were applied to the high surface area membranes. Consequently, the Fe and Ru loadings in the membranes were likely to be smaller than those expected for complete monolayer coverage. In addition, there was likely to be significant variation in the Fe and Ru loading among the membranes due to difficulties in nucleating these materials on the aluminum oxide

  9. Uranium triamidoamine chemistry.

    Science.gov (United States)

    Gardner, Benedict M; Liddle, Stephen T

    2015-07-01

    Triamidoamine (Tren) complexes of the p- and d-block elements have been well-studied, and they display a diverse array of chemistry of academic, industrial and biological significance. Such in-depth investigations are not as widespread for Tren complexes of uranium, despite the general drive to better understand the chemical behaviour of uranium by virtue of its fundamental position within the nuclear sector. However, the chemistry of Tren-uranium complexes is characterised by the ability to stabilise otherwise reactive, multiply bonded main group donor atom ligands, construct uranium-metal bonds, promote small molecule activation, and support single molecule magnetism, all of which exploit the steric, electronic, thermodynamic and kinetic features of the Tren ligand system. This Feature Article presents a current account of the chemistry of Tren-uranium complexes.

  10. Diversity and Periodicity: An Inorganic Chemistry Module.

    Science.gov (United States)

    Huheey, James

    This book is one in a series of Interdisciplinary Approaches to Chemistry (IAC) designed to help students discover that chemistry is a lively science and actively used to pursue solutions to the important problems of today. It is expected for students to see how chemistry takes place continuously all around and to readily understand the daily…

  11. Significant steps in the evolution of analytical chemistry--is the today's analytical chemistry only chemistry?

    Science.gov (United States)

    Karayannis, Miltiades I; Efstathiou, Constantinos E

    2012-12-15

    In this review the history of chemistry and specifically the history and the significant steps of the evolution of analytical chemistry are presented. In chronological time spans, covering the ancient world, the middle ages, the period of the 19th century, and the three evolutional periods, from the verge of the 19th century to contemporary times, it is given information for the progress of chemistry and analytical chemistry. During this period, analytical chemistry moved gradually from its pure empirical nature to more rational scientific activities, transforming itself to an autonomous branch of chemistry and a separate discipline. It is also shown that analytical chemistry moved gradually from the status of exclusive serving the chemical science, towards serving, the environment, health, law, almost all areas of science and technology, and the overall society. Some recommendations are also directed to analytical chemistry educators concerning the indispensable nature of knowledge of classical analytical chemistry and the associated laboratory exercises and to analysts, in general, why it is important to use the chemical knowledge to make measurements on problems of everyday life.

  12. Industrial chemistry engineering

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-01-15

    This book on industrial chemistry engineering is divided in two parts. The first part deals with industrial chemistry, inorganic industrial chemistry, organic industrial chemistry, analytical chemistry and practical questions. The last parts explain the chemical industry, a unit parts and thermodynamics in chemical industry and reference. It reveals the test subjects for the industrial chemistry engineering with a written examination and practical skill.

  13. Detection of O-propargyl-puromycin with SUMO and ubiquitin by click chemistry at PML-nuclear bodies during abortive proteasome activities

    Energy Technology Data Exchange (ETDEWEB)

    Uozumi, Naoki; Matsumoto, Hotaru [Course for Biological Sciences, Faculty of Science, Kumamoto University, Kumamoto (Japan); Saitoh, Hisato, E-mail: hisa@kumamoto-u.ac.jp [Course for Biological Sciences, Faculty of Science, Kumamoto University, Kumamoto (Japan); Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kumamoto (Japan)

    2016-05-27

    The amino-nucleoside antibiotic, puromycin, acts by covalently linking to elongating polypeptide chains on ribosomes to generate prematurely terminated immature polypeptides. The trafficking of puromycin-conjugated (puromycylated) immature polypeptides within cell has, however, remained elusive. In this study, using O-propargyl-puromycin (OP-Puro), the distribution of puromycylated polypeptides was assessed in HeLa cells by click chemistry. Under standard culture conditions, OP-Puro signals were detected in the cytoplasm and nucleus with the highest concentrations in the nucleolus. Intriguingly, when proteasome activities were aborted using MG132, OP-Puro signals began to accumulate at promyelocytic leukemia nuclear bodies (PML-NBs) in addition to the nucleolus. We also found promiscuous association of OP-Puro signals with SUMO-2/3 and ubiquitin at PML-NBs, but not at the nucleolus, during abortive proteasome activities. This study reveals a previously unknown distribution of OP-Puro that argues for a nuclear function in regulating immature protein homeostasis. -- Highlights: •Click chemistry detects O-propargyl-puromycin (OP-Puro) signals in the nucleus. •OP-Puro accumulates at PML-NBs during abortive proteasome activities. •SUMO and ubiquitin are promiscuously associated with OP-Puro at PML-NBs. •The nucleus may function in immature protein homeostasis.

  14. Click chemistry inspired one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles and their Src kinase inhibitory activity.

    Science.gov (United States)

    Kumar, Dalip; Reddy, V Buchi; Kumar, Anil; Mandal, Deendayal; Tiwari, Rakesh; Parang, Keykavous

    2011-01-01

    Two classes of 1,4-disubstituted 1,2,3-triazoles were synthesized using one-pot reaction of α-tosyloxy ketones/α-halo ketones, sodium azide, and terminal alkynes in the presence of aq PEG (1:1, v/v) using the click chemistry approach and evaluated for Src kinase inhibitory activity. Structure-activity relationship analysis demonstrated that insertion of C(6)H(5)- and 4-CH(3)C(6)H(4)- at position 4 for both classes and less bulkier aromatic group at position 1 in class 1 contribute critically to the modest Src inhibition activity (IC(50) = 32-43 μM) of 1,4-disubstituted 1,2,3-triazoles.

  15. Computational chemistry

    Science.gov (United States)

    Arnold, J. O.

    1987-01-01

    With the advent of supercomputers, modern computational chemistry algorithms and codes, a powerful tool was created to help fill NASA's continuing need for information on the properties of matter in hostile or unusual environments. Computational resources provided under the National Aerodynamics Simulator (NAS) program were a cornerstone for recent advancements in this field. Properties of gases, materials, and their interactions can be determined from solutions of the governing equations. In the case of gases, for example, radiative transition probabilites per particle, bond-dissociation energies, and rates of simple chemical reactions can be determined computationally as reliably as from experiment. The data are proving to be quite valuable in providing inputs to real-gas flow simulation codes used to compute aerothermodynamic loads on NASA's aeroassist orbital transfer vehicles and a host of problems related to the National Aerospace Plane Program. Although more approximate, similar solutions can be obtained for ensembles of atoms simulating small particles of materials with and without the presence of gases. Computational chemistry has application in studying catalysis, properties of polymers, all of interest to various NASA missions, including those previously mentioned. In addition to discussing these applications of computational chemistry within NASA, the governing equations and the need for supercomputers for their solution is outlined.

  16. Quantitation of sensory-active and bioactive constituents of food: A Journal of Agricultural and Food Chemistry perspective.

    Science.gov (United States)

    Schieberle, Peter; Molyneux, Russell J

    2012-03-14

    The proper procedures for the measurement of amounts of compounds that may occur in a food or other matrices are presented in this perspective. Factors dealt with include sampling, use of standards, advantages and limitations of chromatographic and other techniques for quantitation, and proper presentation and reporting of data. Such factors must be considered at the initial stages of an investigation and incorporated completely into the overall experimental design. These standards are to be employed in determining quantities of such components, and their careful incorporation should result in more favorable evaluation of manuscripts submitted to the Journal of Agricultural and Food Chemistry.

  17. Thermal modification of activated carbon surface chemistry improves its capacity as redox mediator for azo dye reduction

    OpenAIRE

    Pereira, Luciana; Pereira, Ricardo; Pereira, M. F. R.; Van der Zee, F. P.; Cervantes, F. J.; Alves, M.M.

    2010-01-01

    The surface chemistry of a commercial AC (AC0) was selectively modified, without changing significantly its textural properties, by chemical oxidation with HNO3 (ACHNO3 ) and O2 (ACO2 ), and thermal treatments under H2 (ACH2) or N2 (ACN2 ) flow. The effect of modified AC on anaerobic chemical dye reduction was assayed with sulphide at different pH values 5, 7 and 9. Four dyes were tested: Acid Orange 7, Reactive Red 2, Mordant Yellow 10 and Direct Blue 71. Batch experiments with l...

  18. 化学在幼儿科学活动中的运用之研究%A Study on the Application of Chemistry in Children's Scientific Activities

    Institute of Scientific and Technical Information of China (English)

    马文娟

    2013-01-01

    Science education in kindergartens are mainly related to subjects such as physics and biology. In contrast, science of chemistry is seldom included. Therefore, attempts should be made to add chemical knowledge to science education in kinder-gartens. On the basis of chemical reactions, some scientific activ-ities should be designed to study the application of chemistry in children's enlightenment education.%  在幼儿园的科学教育活动内容中,理科知识多是涉及物理、生物等学科知识,化学科学的渗透则比较贫乏。我们在幼儿科学活动中尝试性地加入化学内容,以化学反应为载体开发设计出一些科学活动,并研究化学在幼儿科学启蒙教育中的运用。

  19. Theoretical chemistry periodicities in chemistry and biology

    CERN Document Server

    Eyring, Henry

    1978-01-01

    Theoretical Chemistry: Periodicities in Chemistry and Biology, Volume 4 covers the aspects of theoretical chemistry. The book discusses the stably rotating patterns of reaction and diffusion; the chemistry of inorganic systems exhibiting nonmonotonic behavior; and population cycles. The text also describes the mathematical modeling of excitable media in neurobiology and chemistry; oscillating enzyme reactions; and oscillatory properties and excitability of the heart cell membrane. Selected topics from the theory of physico-chemical instabilities are also encompassed. Chemists, mechanical engin

  20. The radiation chemistry of macromolecules

    CERN Document Server

    1973-01-01

    The Radiation Chemistry of Macromolecules, Volume II is a collection of papers that discusses radiation chemistry of specific systems. Part 1 deals with radiation chemistry of substituted vinyl polymers, particularly polypropylene (PP) as its structure is intermediate between polyethylene and polyisobutylene. This part also discusses polypropylene oxide (PPOx) for it can be prepared in the atactic, isotactic, and optically active forms. One paper focuses on the fundamental chemical processes and the changes in physical properties that give rise to many different applications of polystyrene. An

  1. Surface chemistry

    CERN Document Server

    Desai, KR

    2008-01-01

    The surface Chemistry of a material as a whole is crucially dependent upon the Nature and type of surfaces exposed on crystallites. It is therefore vitally important to independently Study different, well - defined surfaces through surface analytical techniques. In addition to composition and structure of surface, the subject also provides information on dynamic light scattering, micro emulsions, colloid Stability control and nanostructures. The present book endeavour to bring before the reader that the understanding and exploitation of Solid state phenomena depended largely on the ability to

  2. Temperature dependence of bromine activation due to reaction of bromide with ozone in a proxy for organic aerosols and its importance for chemistry in surface snow.

    Science.gov (United States)

    Edebeli, Jacinta; Ammann, Markus; Gilgen, Anina; Trachsel, Jürg; Avak, Sven; Eichler, Anja; Schneebeli, Martin; Bartels-Rausch, Thorsten

    2017-04-01

    Tropospheric ozone depletion events (ODEs) via halogen activation are observed in both cold and warm climates [1-3]. Very recently, it was suggested that this multiphase halogen activation chemistry dominates in the tropical and subtropical upper troposphere [4]. These occurrences beg the question of temperature dependence of halogen activation in sea-salt aerosol, which are often mixtures of sea-salt and organic molecules [3, 5]. With the application of flow-tubes, the aim of this study is to investigate the temperature dependence of bromine activation via ozone interaction in a bromide containing film as a proxy for mixed organic - sea-salt aersol. Citric acid is used in this study as a hygroscopically characterized matrix and a proxy for oxidized organics, which is of relevance to atmospheric chemistry. Here, we present reactive ozone uptake measured between 258 and 289 K. The data show high reproducibility. With available knowledge, we have reproduced the measured uptake with modelled bulk uptake while accounting for temperature dependence of the substrate's properties as diffusivity, viscosity, and gas solubility. This work is part of a cross-disciplinary project with the aim to investigate the impact of metamorphism on impurity location in aging snow and its consequences for chemical reactivity. Metamorphism drastically shapes the structure and physical properties of snow, which has impacts on heat transfer, albedo, and avalanche formation. Such changes can be driven by water vapour fluxes in dry metamorphism with a mass turnover of as much as 60% per day - much greater than previously thought [6]. The consequences for atmospheric science are a current question of research [7]. Here, we show first results of a joint experiment to probe the re-distribution of impurities during snow metamorphism in artificial snow combined with an investigation of the samples structural changes. Future work is planned with the goal to investigate to which extend the observed re

  3. Approaching isomerism in organic and inorganic compounds: activity based on the use of problem situations during initial chemistry teacher training

    Directory of Open Access Journals (Sweden)

    osé Euzébio Simões Neto

    2013-08-01

    Full Text Available This study sought investigate: i the understanding of isomerism by future chemistry teachers during initial training; and ii the construction of isomer concepts after an approach centered on problem situations (SP’s. Two problem situations related to isomerism (historical context and medicinal applications were elaborated. A textual learning material developed for this purpose and concrete molecular models were used of system resources in the problem situation resolution process. Data were colleted using a questionnaire, field observation and semi-structured interview, and analyzed according to the ideas presented by Meirieu (1998. The two SP’s had obstacles, transposable to only a few of the nine groups that responded. Inadequate use of the isomer concept was observed in many of the responses considered scarcely satisfactory or unsatisfactory.

  4. Spectroscopic and modeling investigations of the gas-phase chemistry and composition in microwave plasma activated B2H6/Ar/H2 mixtures.

    Science.gov (United States)

    Ma, Jie; Richley, James C; Davies, David R W; Cheesman, Andrew; Ashfold, Michael N R; Mankelevich, Yuri A

    2010-02-25

    This paper describes a three-pronged study of microwave (MW) activated B(2)H(6)/Ar/H(2) plasmas as a precursor to diagnosis of the B(2)H(6)/CH(4)/Ar/H(2) plasmas used for the chemical vapor deposition of B-doped diamond. Absolute column densities of B atoms and BH radicals have been determined by cavity ring-down spectroscopy as a function of height (z) above a molybdenum substrate and of the plasma process conditions (B(2)H(6) and Ar partial pressures, total pressure, and supplied MW power). Optical emission spectroscopy has been used to explore variations in the relative densities of electronically excited BH, H, and H(2) species as a function of the same process conditions and of time after introducing B(2)H(6) into a pre-existing Ar/H(2) plasma. The experimental measurements are complemented by extensive 2-D(r, z) modeling of the plasma chemistry, which results in refinements to the existing B/H chemistry and thermochemistry and demonstrates the potentially substantial loss of gas-phase BH(x) species through reaction with trace quantities of air/O(2) in the process gas mixture and heterogeneous processes occurring at the reactor wall.

  5. [Pharmaceutical chemistry of general anaesthetics].

    Science.gov (United States)

    Szász, György; Takácsné, Novák Krisztina

    2004-01-01

    The paper represents the first part of a planned series of reviews about pharmaceutical chemistry of drugs acting on the central nervous system. The authorial aim and editorial concepts are the same were followed in a former series of papers about pharmaceutical chemistry of agents effecting the heart, blood circulation and vegetative nervous system. Consequently, general anaesthetics are discussed in the present paper through the chapters "history, preparation; structure-properties-activity; application; analysis".

  6. Why Teach Environmental Chemistry?

    Science.gov (United States)

    Gardner, Marjorie H.

    1974-01-01

    Discusses the importance of teaching environmental chemistry in secondary school science classes, and outlines five examples of environmental chemistry problems that focus on major concepts of chemistry and have critical implications for human survival and well-being. (JR)

  7. Science Update: Inorganic Chemistry

    Science.gov (United States)

    Rawls, Rebecca

    1978-01-01

    This first in a series of articles describing the state of the art of various branches of chemistry reviews inorganic chemistry, including bioinorganic, photochemistry, organometallic, and solid state chemistries. (SL)

  8. Environmental chemistry. Seventh edition

    Energy Technology Data Exchange (ETDEWEB)

    Manahan, S.E. [Univ. of Missouri, Columbia, MO (United States)

    1999-11-01

    This book presents a basic understanding of environmental chemistry and its applications. In addition to providing updated materials in this field, the book emphasizes the major concepts essential to the practice of environmental chemistry. Topics of discussion include the following: toxicological chemistry; toxicological chemistry of chemical substances; chemical analysis of water and wastewater; chemical analysis of wastes and solids; air and gas analysis; chemical analysis of biological materials and xenobiotics; fundamentals of chemistry; and fundamentals of organic chemistry.

  9. Combustion chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Brown, N.J. [Lawrence Berkeley Laboratory, CA (United States)

    1993-12-01

    This research is concerned with the development and use of sensitivity analysis tools to probe the response of dependent variables to model input variables. Sensitivity analysis is important at all levels of combustion modeling. This group`s research continues to be focused on elucidating the interrelationship between features in the underlying potential energy surface (obtained from ab initio quantum chemistry calculations) and their responses in the quantum dynamics, e.g., reactive transition probabilities, cross sections, and thermal rate coefficients. The goals of this research are: (i) to provide feedback information to quantum chemists in their potential surface refinement efforts, and (ii) to gain a better understanding of how various regions in the potential influence the dynamics. These investigations are carried out with the methodology of quantum functional sensitivity analysis (QFSA).

  10. Astronomical chemistry.

    Science.gov (United States)

    Klemperer, William

    2011-01-01

    The discovery of polar polyatomic molecules in higher-density regions of the interstellar medium by means of their rotational emission detected by radioastronomy has changed our conception of the universe from essentially atomic to highly molecular. We discuss models for molecule formation, emphasizing the general lack of thermodynamic equilibrium. Detailed chemical kinetics is needed to understand molecule formation as well as destruction. Ion molecule reactions appear to be an important class for the generally low temperatures of the interstellar medium. The need for the intrinsically high-quality factor of rotational transitions to definitively pin down molecular emitters has been well established by radioastronomy. The observation of abundant molecular ions both positive and, as recently observed, negative provides benchmarks for chemical kinetic schemes. Of considerable importance in guiding our understanding of astronomical chemistry is the fact that the larger molecules (with more than five atoms) are all organic.

  11. One-step affinity purification of recombinant urokinase-type plasminogen activator receptor using a synthetic peptide developed by combinatorial chemistry

    DEFF Research Database (Denmark)

    Jacobsen, B.; Gerdsvoll, H.; Funch, G.J.

    2007-01-01

    purification of a soluble, recombinant uPAR using the monoclonal antibody R2 or the peptide AE152 immobilized on Sepharose. The two affinity ligands perform equally well in purifying uPAR from Drosophila melanogaster Schneider 2 cell culture medium and yield products of comparable purity, activity...... purification of recombinant uPAR exploiting a high-affinity synthetic peptide antagonist (AE152). The corresponding parent peptide was originally identified in a random phage-display library and subsequently subjected to affinity maturation by combinatorial chemistry. This study compares the affinity......, and stability as judged by SDS-PAGE, size exclusion chromatography and surface plasmon resonance analysis. The general availability of peptide synthesis renders the present AE152-based affinity purification of uPAR more accessible than the traditional protein-based affinity purification strategies. In this way...

  12. Coordination Chemistry of Polyaromatic Thiosemicarbazones 2: Synthesis and Biological Activity of Zinc, Cobalt, and Copper Complexes of 1-(Naphthalene-2-ylethanone Thiosemicarbazone

    Directory of Open Access Journals (Sweden)

    Marc-Andre LeBlanc

    2011-01-01

    Full Text Available A novel thiosemicarbazone from 2-acetonaphthone (represented as acnTSC has been synthesized and its basic coordination chemistry with zinc(II, cobalt(II, and copper(II explored. The complexes were characterized by elemental analysis and various spectroscopic techniques and are best formulated as [M(acnTSC2Cl2] with the metal likely in an octahedral environment. The anticancer activity of the complexes was determined against a panel of human colon cancer cells (HCT-116 and Caco-2. The compounds bind to DNA via an intercalative mode with binding constants of 9.7×104 M-1, 1.8×105 M-1, and 9.5×104 M-1 for the zinc, cobalt, and copper complexes, respectively.

  13. Basic organic chemistry association (SCOB): strengthen the competitiveness while waiting the renewal of activities; SCOB: consolider la competitivite en attendant la reprise

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2003-08-01

    'For a lot of reasons, the petrochemistry sector has been revealed very problematical last year' has revealed the new president of basic organic chemistry association (SCOB), Andre Renoux, during the usual press conference he has done. After a year 2001, already morose for the petrochemistry sector, the some positive renewal signals that seemed to appear at the beginning of the year 2002 have rapidly disappeared. For taking stock of the situation, 'the year 2002 is a second disappointing year for the monomers sector, with low results and a year always unsatisfying for the polymers activity' has commented Andre Renoux. In this unstable economic environment, petrochemistry continue to reaffirm its priority given to safety, backbone of a real lasting development. Waiting for a reversal of tendency involved for the second middle of the year. (O.M.)

  14. Synthesis via “click chemistry" of new triazole analogues derivatives of grandisin and veraguensin neolignans with potential trypanocidal and leishmanicidal activity

    Directory of Open Access Journals (Sweden)

    Tatiana C Bortolo

    2012-06-01

    Full Text Available Using the concept of bioisosterism, new triazole analogs were designed from the molecular modification of grandisin and veraguensin neolignans   which have a furan group that is a bioisóstere of 1,2,3-triazoles ring. In order to obtain more potent compounds, with fewer side effects, and better physical and chemical characteristics in combating leishmaniasis and chagas disease, this research group synthesized, via "Click Chemistry", eight new triazole analogues of neolignans. Thus reactions 1,3-dipolar cycloaddition of Huisgen were performed between terminal acetylenes and azides previously synthesized. The catalytic system CuSO4.5H2O/Ascorbate Sodium / CH2Cl2/H2O was used and, under this reaction conditions eight triazole analogues were synthesized in good yields. Trypanocidal activity test showed positive for the eight molecules.

  15. High school chemistry students' learning of the elements, structure, and periodicity of the periodic table: Contributions of inquiry-based activities and exemplary graphics

    Science.gov (United States)

    Roddy, Knight Phares, Jr.

    The main research question of this study was: How do selected high school chemistry students' understandings of the elements, structure, and periodicity of the Periodic Table change as they participate in a unit study consisting of inquiry-based activities emphasizing construction of innovative science graphics? The research question was answered using a multiple case study/mixed model design which employed elements of both qualitative and quantitative methodologies during data collection and analyses. The unit study was conducted over a six-week period with 11th -grade students enrolled in a chemistry class. A purposive sample of six students from the class was selected to participate in interviews and concept map coconstruction (Wandersee & Abrams, 1993) periodically across the study. The progress of the selected students of the case study was compared to the progress of the class as a whole. The students of the case study were also compared to a group of high school chemistry students at a comparative school. The results show that the students from both schools left traditional instruction on the periodic table (lecture and textbook activities) with a very limited understanding of the topic. It also revealed that the inquiry-based, visual approach of the unit study helped students make significant conceptual progress in their understanding of the periodic table. The pictorial periodic table (which features photographs of the elements), used in conjunction with the graphic technique of data mapping, enhanced students understanding of the patterns of the physical properties of the elements on the periodic table. The graphic technique of compound mapping helped students learn reactivity patterns between types and groups of elements on the periodic table. The recreation of the periodic table with element cards created from the pictorial periodic table helped students progress in their understanding of periodicity and its key concepts. The Periodic Table Literacy

  16. [JSPS Asia and Africa scientific platform program development for the medicinal chemistry based on biologically active natural products in the subtropical zone].

    Science.gov (United States)

    Saito, Naoki; Morita, Takashi

    2009-04-01

    In 2005, the independent administrative institution the "Japan Society for the Promotion of Sciences (JSPS)" initiated the "Asia and Africa Science Platform Program", which is a new project aimed to create high potential research hubs in selected fields within the Asian and African region, while fostering the next generation of leading researchers. Another goal is to establish sustainable collaborative relationships among universities and research institutes in Japan and other Asian and African countries. In this project, we consider natural sources existing in partner countries to be the most important factor in the production of medicine. We will search for target compounds and analyze their structures by screening biologically active natural products. Additionally, we will design functional molecules and create process for retrieving a large supply of target compounds based on a bioprospecting strategy. Thailand, Indonesia, and India share the vision of enhancing collaborative efforts. By conducting this researche, we will focus on academic research that is necessary for the development of the pharmaceutical and medical products industry in partner countries. There are four selected research topics as followeds: 1) Development of New Antitumor Agents based on Marine Natural Products; 2) Development of New Anticoagulants and Anti-VEGF; 3) Molecular Epidemiological Investigation of Emerging Infectious Diseases and Development of Novel Diagnosis and Therapeutic Agents; and 4) Medicinal Chemistry on Biologically Active Natural Products from the Traditional Condiments and Medicines. The exchanges might take the form of joint research seminars. The first Medicinal Chemistry Seminar of the AA Scientific Platform Program was co-organized with the 23th Annual Research Conference on Pharmaceutical Sciences, Thailand at Chulalongkorn University, Bangkok, on December 14-15, 2006. The 2nd JSPS seminar was co-organized with the 1st Bioactive Natural Products from Marine

  17. Storylines in intercalation chemistry.

    Science.gov (United States)

    Lerf, A

    2014-07-21

    Intercalation chemistry will soon be a hundred years old. The period of greatest activity in this field of solid state chemistry and physics was from about 1970 to 1990. The intercalation reactions are defined as topotactic solid state reactions and the products--the intercalation compounds--are clearly distinguished from inclusion and interstitial compounds. After a short historical introduction emphasizing the pioneering work of Ulrich Hofmann, the central topics and concepts will be reviewed and commented on. The most important ones, in my view, are: dichalcogenide intercalation compounds, the electrochemical intercalation and the search for new battery electrodes, the physics of graphite intercalation compounds, and the staging and interstratification phenomena. The relation to other fields of actual research and the demands for forthcoming research will also be addressed.

  18. Science Update: Inorganic Chemistry.

    Science.gov (United States)

    Rawls, Rebecca

    1981-01-01

    Describes areas of inorganic chemistry which have changed dramatically in the past year or two, including photochemistry, electrochemistry, organometallic complexes, inorganic reaction theory, and solid state chemistry. (DS)

  19. Advanced Chemistry Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Description/History: Chemistry laboratory The Advanced Chemistry Laboratory (ACL) is a unique facility designed for working with the most super toxic compounds known...

  20. Chemistry Teacher Education Coalition: Extending the PhysTEC Model to Chemistry

    Science.gov (United States)

    Kirchhoff, Mary

    2012-02-01

    The American Association of Employment in Education reports that chemistry, like physics, faces ``some shortage'' of educators. Inspired by the success of the Physics Teacher Education Coalition (PhysTEC), the American Chemical Society (ACS) is developing the Chemistry Teacher Education Coalition (CTEC) to actively engage chemistry departments in the preparation of future chemistry teachers. Engaging chemistry departments in teacher preparation would increase the number and diversity of well-prepared high school chemistry teachers while catalyzing cultural change within chemistry departments. Many features of PhysTEC, such as a grant competition to create model teacher preparation programs and regular conferences, are directly applicable to chemistry. This presentation will provide an overview of ACS efforts to launch a successful CTEC initiative.

  1. The influence of modified water chemistries on metal oxide films, activity build-up and stress corrosion cracking of structural materials in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Maekelae, K.; Laitinen, T.; Bojinov, M. [VTT Manufacturing Technology, Espoo (Finland)

    1999-03-01

    The primary coolant oxidises the surfaces of construction materials in nuclear power plants. The properties of the oxide films influence significantly the extent of incorporation of actuated corrosion products into the primary circuit surfaces, which may cause additional occupational doses for the maintenance personnel. The physical and chemical properties of the oxide films play also an important role in different forms of corrosion observed in power plants. This report gives a short overview of the factors influencing activity build-up and corrosion phenomena in nuclear power plants. Furthermore, the most recent modifications in the water chemistry to decrease these risks are discussed. A special focus is put on zinc water chemistry, and a preliminary discussion on the mechanism via which zinc influences activity build-up is presented. Even though the exact mechanisms by which zinc acts are not yet known, it is assumed that Zn may block the diffusion paths within the oxide film. This reduces ion transport through the oxide films leading to a reduced rate of oxide growth. Simultaneously the number of available adsorption sites for {sup 60}Co is also reduced. The current models for stress corrosion cracking assume that the anodic and the respective cathodic reactions contributing to crack growth occur partly on or in the oxide films. The rates of these reactions may control the crack propagation rate and therefore, the properties of the oxide films play a crucial role in determining the susceptibility of the material to stress corrosion cracking. Finally, attention is paid also on the novel techniques which can be used to mitigate the susceptibility of construction materials to stress corrosion cracking. (orig.) 127 refs.

  2. Chemistry of Cigarette Burning Processes

    Directory of Open Access Journals (Sweden)

    Chen P

    2014-12-01

    Full Text Available Cigarette-burning and the smoke-formation processes and smoke composition are important topics for understanding cigarette performance. This paper proposes the molecular formulas representing the active components of bright, burley, and Oriental tobaccos and a basic chemistry model of the cigarette burning processes. Previous knowledge of the cigarette burning processes and smoke formation helped to establish parameters in deriving the basic chemistry equations. The proposed chemistry provides a brief view of the mechanisms of the cigarette burning during puffing and interpuff smoldering, and can be used to interpret and predict the smoke composition for cigarettes made from bright, burley, and Oriental tobaccos. Based on the proposed chemistry, the effect of ventilation on smoke component deliveries is discussed and the reaction heat of the puffing process is estimated.

  3. One-pot synthesis of new triazole--Imidazo[2,1-b][1,3,4]thiadiazole hybrids via click chemistry and evaluation of their antitubercular activity.

    Science.gov (United States)

    Ramprasad, Jurupula; Nayak, Nagabhushana; Dalimba, Udayakumar; Yogeeswari, Perumal; Sriram, Dharmarajan

    2015-10-01

    A new series of triazole-imidazo[2,1-b][1,3,4]thiadiazole hybrids (6a-s, 7a) were designed by a molecular hybridisation approach and the target molecules were synthesized via one pot click chemistry protocol. All the intermediates and final molecules were characterised using spectral methods and one of the target compounds (6c) was analysed by the single crystal XRD study. The derivatives were screened for their antimycobacterial activity against Mycobacterium tuberculosis H37Rv strain. Two compounds, 6f and 6n, demonstrated significant growth inhibitory activity against the bacterial strain with a MIC of 3.125 μg/mL. The presence of chloro substituent on the imidazo[2,1-b][1,3,4]thiadiazole ring and ethyl, benzyl or cyanomethylene groups on the 1,2,3-triazole ring enhance the inhibition activity of the molecules. The active compounds are not toxic to a normal cell line which signifies the lack of general cellular toxicity of these compounds.

  4. Design, synthesis, and anticancer activity of novel berberine derivatives prepared via CuAAC “click” chemistry as potential anticancer agents

    Directory of Open Access Journals (Sweden)

    Jin X

    2014-08-01

    Full Text Available Xin Jin1,2,* Tian-Hua Yan,3,* Lan Yan,1 Qian Li,4 Rui-Lian Wang,1 Zhen-Lin Hu,1 Yuan-Ying Jiang,1 Qing-Yan Sun,1 Yong-Bing Cao1 1School of Pharmacy, Second Military Medical University, Shanghai, People's Republic of China; 2School of Pharmacy, FuJian University of Traditional Chinese Medicine, Fuzhou, People's Republic of China; 3Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, People's Republic of China; 4Diakite Biological Technology Co., Ltd, Shanghai, People's Republic of China *These authors contributed equally to this work Abstract: A series of novel derivatives of phenyl-substituted berberine triazolyls has been designed and synthesized via copper-catalyzed azide-alkyne cycloaddition click chemistry in an attempt to develop antitumor agents. All of the compounds were evaluated for anticancer activity against a panel of three human cancer cell lines, including MCF-7 (breast, SW-1990 (pancreatic, and SMMC-7721 (liver and the noncancerous human umbilical vein endothelial cell (HUVEC cell lines. The results indicated that most of the compounds displayed notable anticancer activities against the MCF-7 cells compared with berberine. Among these derivatives, compound 16 showed the most potent inhibitory activity against the SW-1990 and SMMC-7721 cell lines, with half-maximal inhibitory concentration (IC50 values of 8.54±1.97 µM and 11.87±1.83 µM, respectively. Compound 36 exhibited the most potent inhibitory activity against the MCF-7 cell line, with an IC50 value of 12.57±1.96 µM. Compound 16 and compound 36 exhibited low cytotoxicity in the HUVEC cell line, with IC50 values of 25.49±3.24 µM and 30.47±3.47 µM. Furthermore, compounds 14, 15, 16, 17, 18, 32, and 36 exhibited much better selectivity than berberine toward the normal cell line HUVEC. Keywords: berberine, anticancer, click chemistry, structure–activity relationship

  5. Modification of Activated Carbon by Means of Microwave Heating and Its Effects on the Pore Texture and Surface Chemistry

    OpenAIRE

    2013-01-01

    Two kinds of typical activated carbons (coal based AC and coconut shell based AC) were modified in a flow of N2 gas has been carried out using a microwave device operating at 2450 MHz and different input power, instead of a conventional furnace. The samples were analyzed by means of low temperature N2 adsorption, elemental analysis and Boehm titration. The results show that microwave heating is an effective means of activated carbon modification. The temperature of activated carbon increases ...

  6. Medicinal Chemistry of the Anti-Diabetic Effects of Momordica Charantia: Active Constituents and Modes of Actions

    Science.gov (United States)

    Singh, Jaipaul; Cumming, Emmanuel; Manoharan, Gunasekar; Kalasz, Huba; Adeghate, Ernest

    2011-01-01

    medicinal chemistry and use(s) of M. charantia and its various extracts and compounds, their biochemical properties and how they act as anti-diabetic (hypoglycemic) drugs and the various mechanisms by which they exert their beneficial effects in controlling and treating DM. PMID:21966327

  7. Physical chemistry and the environment

    Energy Technology Data Exchange (ETDEWEB)

    Dunning, T.H. Jr.; Garrett, B.C.; Kolb, C.E. Jr.; Shaw, R.W.; Choppin, G.R.; Wagner, A.F.

    1994-08-01

    From the ozone hole and the greenhouse effect to plastics recycling and hazardous waste disposal, society faces a number of issues, the solutions to which require an unprecedented understanding of the properties of molecules. We are coming to realize that the environment is a coupled set of chemical systems, its dynamics determining the welfare of the biosphere and of humans in particular. These chemical systems are governed by fundamental molecular interactions, and they present chemists with an unparalleled challenge. The application of current concepts of molecular behavior and of up-to-date experimental and computational techniques can provide us with insights into the environment that are needed to mitigate past damage, to anticipate the impact of current human activity, and to avoid future insults to the environment. Environmental chemistry encompasses a number of separate, yet interlocking, areas of research. In all of these areas progress is limited by an inadequate understanding of the underlying chemical processes involved. Participation of all chemical approaches -- experimental, theoretical and computational -- and of all disciplines of chemistry -- organic, inorganic, physical, analytical and biochemistry -- will be required to provide the necessary fundamental understanding. The Symposium on ``Physical Chemistry and the Environment`` was designed to bring the many exciting and challenging physical chemistry problems involved in environmental chemistry to the attention of a larger segment of the physical chemistry community.

  8. Modification of Activated Carbon by Means of Microwave Heating and Its Effects on the Pore Texture and Surface Chemistry

    Directory of Open Access Journals (Sweden)

    Liqiang Zhang

    2013-02-01

    Full Text Available Two kinds of typical activated carbons (coal based AC and coconut shell based AC were modified in a flow of N2 gas has been carried out using a microwave device operating at 2450 MHz and different input power, instead of a conventional furnace. The samples were analyzed by means of low temperature N2 adsorption, elemental analysis and Boehm titration. The results show that microwave heating is an effective means of activated carbon modification. The temperature of activated carbon increases rapidly under microwave heating and then gradual increase to a quasi-stationary temperature. The pore texture of activated carbon changes slightly after microwave treatment and the two activated carbons still keep rich pore structure. The oxygen functional groups decompose and evolve with the form of CO and CO2. This in turn gives rise to a significant decrease in oxygen content. These changes of oxygen contents increase as the microwave input power increases. During microwave treatment, a gradual decrease in the surface acidic functional groups is observed. More important, with the removal of the surface acidic groups, the number of the basic group increased gradually, the activated carbon with oxygen functional groups become basic properties material.

  9. Modification of Activated Carbon by Means of Microwave Heating and Its Effects on the Pore Texture and Surface Chemistry

    Directory of Open Access Journals (Sweden)

    Bing Li

    2013-02-01

    Full Text Available Two kinds of typical Activated Carbons (coal based AC and coconut shell based AC were modified in a flow of N0 gas has been carried out using a microwave device operating at 2450 MHz and different input power, instead of a conventional furnace. The samples were analyzed by means of low temperatureN0 adsorption, elemental analysis and Boehm titration. The results show that microwave heating is an effective means of activated carbon modification. The temperature of activated carbon increases rapidly under microwave heating and then gradual increase to a quasi-stationary temperature. The pore texture of activated carbon changes slightly after microwave treatment and the two activated carbons still keep rich pore structure. The oxygen functional groups decompose and evolve with the form of CO and CO2. This in turn gives rise to a significant decrease in oxygen content. These changes of oxygen contents increase as the microwave input power increases. During microwave treatment, a gradual decrease in the surface acidic functional groups is observed. More important, with the removal of the surface acidic groups, the number of the basic group increased gradually, the activated carbon with oxygen functional groups become basic properties material.

  10. [An approach to the history of scientific documentation in Catalonia. The activity of María Serrallach Juliá (1905-1992) in the Seminary of Chemistry of the University of Barcelona (1937-1984)].

    Science.gov (United States)

    Olagüe de Ros, Guillermo

    2014-01-01

    This article contributes a study of Maria Serrallach Juliá (1905-1992), one of the first specialised librarians in Spain. Between 1937 and 1975, she directed the Seminary of Chemistry of the University of Barcelona (initials in Spanish, SQUB), the name given to the space that resulted from the merger of the libraries of the Faculties of Pharmacy and Chemistry of the University. Serrallach turned the SQUB into a modern scientific documentation centre offering services that were practically non-existent in the rest of Spain. The publications and educational activity of Serrallach are also analysed. The history of the SQUB is studied until 1984, when SQUB was transformed into the Library of the Faculties of Physics and Chemistry of the University of Barcelona.

  11. Determining the Quantum Efficiency for Activation of an Organometallic Photoinitiator for Cationic Polymerization: An Experiment for the Physical or Inorganic Chemistry Laboratory

    Science.gov (United States)

    Hayes, David M.; Mahar, Maura; Schnabel, R. Chris; Shah, Paras; Lees, Alistair J.; Jakubek, Vladimir

    2007-01-01

    We present a new laboratory experiment on the photochemistry of organometallic [eta][superscript 5],[eta][superscript 6]-mixed-sandwich compounds, which is suitable for both the physical chemistry and inorganic chemistry laboratory. Specifically, students use 1,10-phenanthroline to trap the intermediate formed when…

  12. Publicising chemistry in a multicultural society through chemistry outreach

    Directory of Open Access Journals (Sweden)

    Joyce D. Sewry

    2011-11-01

    Full Text Available Given the emphasis in Higher Education on community engagement in South Africa and the importance of international collaboration, we discuss a joint approach to chemistry outreach in two countries on two continents with widely differing target school audiences. We describe the history of the partnership between the chemistry departments at Rhodes University and the University of Bristol and provide an outline of the chemistry content of their outreach initiatives, the modes of delivery, the advantages to both departments and their students for involvement in various levels of outreach, the challenges they still face and additional opportunities that such work facilitated. The lecture demonstration ‘A Pollutant’s Tale’ was presented to thousands of learners all over the world, including learners at resource-deprived schools in South Africa. Challenges to extend outreach activities in South Africa include long travelling distances, as well as a lack of facilities (such as school halls and electricity at schools. Outreach activities not only impacted on the target audience of young learners, they also impacted upon the postgraduate and other chemistry students taking part in these initiatives. This collaboration strengthened both institutions and their outreach work and may also lead to chemistry research collaborations between the academics involved.

  13. Green Synthesis, Spectrofluorometric Characterization and Antibacterial Activity of Heterocyclic Compound from Chalcone on the Basis of in Vitro and Quantum Chemistry Calculation.

    Science.gov (United States)

    Khan, Salman A

    2017-02-08

    2-amino-4-(4-bromophenyl)-8-methoxy-5,6-dihydrobenzo[h]quinoline-3-carbonitrile (ABDC) was synthesized by the reaction of (2E)-2-(4 bromobenzylidene) - 6 -methoxy-3,4-dihydronaphthalen-1(2H)-one (Chalcone) with malononitrile and ammonium acetate under microwave irradiation. Chalcone was synthesised by the reaction 4-bromobenzaldehyd, 6-methoxy-1,2,3,4-tetrahydro-naphthalin-1-one under the same condition. Structure of ABDC was conformed by (1)H and (13)C NMR, FT-IR, EI-MS spectral studies and elemental analysis. The electronic absorption and fluorescence spectra of ABDC have been studied in solvents of different polarities, and the data were used to study the solvatochromic properties such as excitation coefficient, stokes shift, oscillator strength, transition dipole moment and fluorescence quantum yield. The absorption maximum and fluorescence emission maximum was observed red shift when increase solvent polarity n-Hexane to DMSO. ABDC undergoes solubilization in different micelles and may be used as a probe and quencher to determine the critical micelle concentration (CMC) of CTAB and SDS. The anti-bacterial activity of chalcone and its cyclized product ABDC was tested in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria was determined with the reference of standard drug Tetracycline. Results showed that the ABDC is better anti-bacterial agent as compared to chalcone. The anti-bacterial activity was further supported by the quantum chemistry calculation.

  14. Detection of O-propargyl-puromycin with SUMO and ubiquitin by click chemistry at PML-nuclear bodies during abortive proteasome activities.

    Science.gov (United States)

    Uozumi, Naoki; Matsumoto, Hotaru; Saitoh, Hisato

    2016-05-27

    The amino-nucleoside antibiotic, puromycin, acts by covalently linking to elongating polypeptide chains on ribosomes to generate prematurely terminated immature polypeptides. The trafficking of puromycin-conjugated (puromycylated) immature polypeptides within cell has, however, remained elusive. In this study, using O-propargyl-puromycin (OP-Puro), the distribution of puromycylated polypeptides was assessed in HeLa cells by click chemistry. Under standard culture conditions, OP-Puro signals were detected in the cytoplasm and nucleus with the highest concentrations in the nucleolus. Intriguingly, when proteasome activities were aborted using MG132, OP-Puro signals began to accumulate at promyelocytic leukemia nuclear bodies (PML-NBs) in addition to the nucleolus. We also found promiscuous association of OP-Puro signals with SUMO-2/3 and ubiquitin at PML-NBs, but not at the nucleolus, during abortive proteasome activities. This study reveals a previously unknown distribution of OP-Puro that argues for a nuclear function in regulating immature protein homeostasis.

  15. Industrial Chemistry and School Chemistry: Making Chemistry Studies More Relevant

    Science.gov (United States)

    Hofstein, Avi; Kesner, Miri

    2006-01-01

    In this paper, we present the development and implementation over the period of more than 15 years of learning materials focusing on industrial chemistry as the main theme. The work was conducted in the Department of Science Teaching at the Weizmann Institute of Science, Israel. The project's general goal was to teach chemistry concepts in the…

  16. From Matter to Life:Chemistry?Chemistry!

    Institute of Scientific and Technical Information of China (English)

    Jean-Marie; LEHN

    2007-01-01

    1 Results Animate as well as inanimate matter,living organisms as well as materials,are formed of molecules and of the organized entities resulting from the interaction of molecules with each other.Chemistry provides the bridge between the molecules of inanimate matter and the highly complex molecular architectures and systems which make up living organisms. Synthetic chemistry has developed a very powerful set of methods for constructing ever more complex molecules.Supramolecular chemistry seeks to con...

  17. Green chemistry: A tool in Pharmaceutical Chemistry

    OpenAIRE

    Smita Talaviya; Falguni Majumdar

    2012-01-01

    Green chemistry expresses an area of research developing from scientific discoveries about pollution awareness and it utilizes a set of principles that reduces or eliminates the use or generation of hazardous substances in all steps of particular synthesis or process. Chemists and medicinal scientists can greatly reduce the risk to human health and the environment by following all the valuable principles of green chemistry. The most simple and direct way to apply green chemistry in pharmaceut...

  18. Computational medicinal chemistry for rational drug design: Identification of novel chemical structures with potential anti-tuberculosis activity.

    Science.gov (United States)

    Koseki, Yuji; Aoki, Shunsuke

    2014-01-01

    Tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis and is a common infectious disease with high mortality and morbidity. The increasing prevalence of drug-resistant strains of TB presents a major public health problem. Due to the lack of effective drugs to treat these drug-resistant strains, the discovery or development of novel anti-TB drugs is important. Computer-aided drug design has become an established strategy for the identification of novel active chemicals through a combination of several drug design tools. In this review, we summarise the current chemotherapy for TB, describe attractive target proteins for the development of antibiotics against TB, and detail several computational drug design strategies that may contribute to the further identification of active chemicals for the treatment of not only TB but also other diseases.

  19. The MOF-driven synthesis of supported palladium clusters with catalytic activity for carbene-mediated chemistry

    Science.gov (United States)

    Fortea-Pérez, Francisco R.; Mon, Marta; Ferrando-Soria, Jesús; Boronat, Mercedes; Leyva-Pérez, Antonio; Corma, Avelino; Herrera, Juan Manuel; Osadchii, Dmitrii; Gascon, Jorge; Armentano, Donatella; Pardo, Emilio

    2017-07-01

    The development of catalysts able to assist industrially important chemical processes is a topic of high importance. In view of the catalytic capabilities of small metal clusters, research efforts are being focused on the synthesis of novel catalysts bearing such active sites. Here we report a heterogeneous catalyst consisting of Pd4 clusters with mixed-valence 0/+1 oxidation states, stabilized and homogeneously organized within the walls of a metal-organic framework (MOF). The resulting solid catalyst outperforms state-of-the-art metal catalysts in carbene-mediated reactions of diazoacetates, with high yields (>90%) and turnover numbers (up to 100,000). In addition, the MOF-supported Pd4 clusters retain their catalytic activity in repeated batch and flow reactions (>20 cycles). Our findings demonstrate how this synthetic approach may now instruct the future design of heterogeneous catalysts with advantageous reaction capabilities for other important processes.

  20. A Cu-amyloid β complex activating Fenton chemistry in Alzheimer's disease: Learning with multiple first-principles simulations

    Science.gov (United States)

    La Penna, Giovanni; Hureau, Christelle; Faller, Peter

    2014-10-01

    Amyloid β peptides form complexes with copper, both in vitro and in vivo, relatively soluble in water as oligomers and active as catalysts for oxidation of organic substrates by hydrogen peroxide, a species always present in cells and in their aerobic environment. All these species are present in the synapse, thus making a connection between the amyloid cascade hypothesis and the oxidative damages by reactive oxygen species in neurons, when pathological dishomeostasis of amyloid peptides and metal ions occur. In order to understand the structural features of these toxic complexes, we built several models of Cu-Aβ peptides in monomeric and dimeric forms and we found, performing multiple first-principles molecular dynamics simulations, that Cu-induced dimers are more active than monomers in converting hydrogen peroxide into aggressive hydroxyl radicals.

  1. Reduction of 68Ge activity containing liquid waste from 68Ga PET chemistry in nuclear medicine and radiopharmacy by solidification

    NARCIS (Netherlands)

    E. de Blois (Erik); H.S. Chan; K. Roy (Kamalika); E.P. Krenning (Eric); W.A.P. Breeman (Wouter)

    2011-01-01

    textabstractPET with68Ga from the TiO2- or SnO2- based68Ge/68Ga generators is of increasing interest for PET imaging in nuclear medicine. In general, radionuclidic purity (68Ge vs.68Ga activity) of the eluate of these generators varies between 0.01 and 0.001%. Liquid waste containing low amounts of6

  2. Methylene bridge regulated geometrical preferences of ligands in cobalt(III) coordination chemistry and phenoxazinone synthase mimicking activity.

    Science.gov (United States)

    Panja, Anangamohan; Shyamal, Milan; Saha, Amrita; Mandal, Tarun Kanti

    2014-04-14

    Two new azide bound cobalt(III) complexes, [Co(L(1))(N3)3] (fac-1) and [Co(L(2))(N3)3] (mer-2), where L(1) is bis(2-pyridylmethyl)amine and L(2) is (2-pyridylmethyl)(2-pyridylethyl)amine, derived from tridentate reduced Schiff-base ligands have been reported. Interestingly, a methylene bridge regulated preferential coordination mode of ligands is noticed in their crystal structures: it is found in a facial arrangement in fac-1 and has a meridional disposition in mer-2. Both complexes show phenoxazinone synthase-like activity and the role of the structural factor on the catalytic activity is also explored. Moreover, the easily reducible cobalt(III) center in mer-2 favors the oxidation of o-aminophenol. The ESI-MS positive spectra together with UV-vis spectroscopy clearly suggest the formation of a catalyst-substrate adduct by substitution of the coordinated azide ions in the catalytic cycle.

  3. Technical Consultation of the International Space Station (ISS) Internal Active Thermal Control System (IATCS) Cooling Water Chemistry

    Science.gov (United States)

    Gentz, Steven J.; Rotter, Hank A.; Easton, Myriam; Lince, Jeffrey; Park, Woonsup; Stewart, Thomas; Speckman, Donna; Dexter, Stephen; Kelly, Robert

    2005-01-01

    The Internal Active Thermal Control System (IATCS) coolant exhibited unexpected chemical changes during the first year of on-orbit operation following the launch and activation in February 2001. The coolant pH dropped from 9.3 to below the minimum specification limit of 9.0, and re-equilibrated between 8.3 and 8.5. This drop in coolant pH was shown to be the result of permeation of CO2 from the cabin into the coolant via Teflon flexible hoses which created carbonic acid in the fluid. This unexpected diffusion was the result of having a cabin CO2 partial pressure higher than the ground partial pressure (average 4.0 mmHg vs. less than 0.2 mmHg). This drop in pH was followed by a concurrent increasing coolant nickel concentration. No other metal ions were observed in the coolant and based on previous tests, the source of nickel ion was thought to be the boron nickel (BNi) braze intermetallics used in the construction of HXs and cold plates. Specifically, BNi2 braze alloy was used for the IATCS IFHX and BNi3 braze alloy was used for the IATCS Airlock Servicing and Performance Checkout Unit (SPCU) HX and cold plates. Given the failure criticality of the HXs, a Corrosion Team was established by the IATCS CWG to determine the impact of the nickel corrosion on hardware performance life.

  4. Medicinal electrochemistry: integration of electrochemistry, medicinal chemistry and computational chemistry.

    Science.gov (United States)

    Almeida, M O; Maltarollo, V G; de Toledo, R A; Shim, H; Santos, M C; Honorio, K M

    2014-01-01

    Over the last centuries, there were many important discoveries in medicine that were crucial for gaining a better understanding of several physiological processes. Molecular modelling techniques are powerful tools that have been successfully used to analyse and interface medicinal chemistry studies with electrochemical experimental results. This special combination can help to comprehend medicinal chemistry problems, such as predicting biological activity and understanding drug action mechanisms. Electrochemistry has provided better comprehension of biological reactions and, as a result of many technological improvements, the combination of electrochemical techniques and biosensors has become an appealing choice for pharmaceutical and biomedical analyses. Therefore, this review will briefly outline the present scope and future advances related to the integration of electrochemical and medicinal chemistry approaches based on various applications from recent studies.

  5. Constitutional dynamic chemistry: bridge from supramolecular chemistry to adaptive chemistry.

    Science.gov (United States)

    Lehn, Jean-Marie

    2012-01-01

    Supramolecular chemistry aims at implementing highly complex chemical systems from molecular components held together by non-covalent intermolecular forces and effecting molecular recognition, catalysis and transport processes. A further step consists in the investigation of chemical systems undergoing self-organization, i.e. systems capable of spontaneously generating well-defined functional supramolecular architectures by self-assembly from their components, thus behaving as programmed chemical systems. Supramolecular chemistry is intrinsically a dynamic chemistry in view of the lability of the interactions connecting the molecular components of a supramolecular entity and the resulting ability of supramolecular species to exchange their constituents. The same holds for molecular chemistry when the molecular entity contains covalent bonds that may form and break reversibility, so as to allow a continuous change in constitution by reorganization and exchange of building blocks. These features define a Constitutional Dynamic Chemistry (CDC) on both the molecular and supramolecular levels.CDC introduces a paradigm shift with respect to constitutionally static chemistry. The latter relies on design for the generation of a target entity, whereas CDC takes advantage of dynamic diversity to allow variation and selection. The implementation of selection in chemistry introduces a fundamental change in outlook. Whereas self-organization by design strives to achieve full control over the output molecular or supramolecular entity by explicit programming, self-organization with selection operates on dynamic constitutional diversity in response to either internal or external factors to achieve adaptation.The merging of the features: -information and programmability, -dynamics and reversibility, -constitution and structural diversity, points to the emergence of adaptive and evolutive chemistry, towards a chemistry of complex matter.

  6. Chemistry, phase formation, and catalytic activity of thin palladium-containing oxide films synthesized by plasma-assisted physical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre

    2010-11-26

    The chemistry, microstructure, and catalytic activity of thin films incorporating palladium were studied using scanning and transmission electron microscopies, X-ray diffraction, spectrophotometry, 4-point probe and catalytic tests. The films were synthesized using pulsed filtered cathodic arc and magnetron sputter deposition, i.e. techniques far from thermodynamic equilibrium. Catalytic particles were formed by thermally cycling thin films of the Pd-Pt-O system. The evolution and phase formation in such films as a function of temperature were discussed in terms of the stability of PdO and PtO2 in air. The catalytic efficiency was found to be strongly affected by the chemical composition, with oxidized palladium definitely playing a major role in the combustion of methane. Reactive sputter deposition of thin films in the Pd-Zr-Y-O system allowed us forming microstructures ranging from nanocrystalline zirconia to palladium nanoparticles embedded in a (Zr,Y)4Pd2O matrix. The sequence of phase formation is put in relation to simple thermodynamic considerations.

  7. Single-Site VO x Moieties Generated on Silica by Surface Organometallic Chemistry: A Way To Enhance the Catalytic Activity in the Oxidative Dehydrogenation of Propane

    KAUST Repository

    Barman, Samir

    2016-07-26

    We report here an accurate surface organometallic chemistry (SOMC) approach to propane oxidative dehydrogenation (ODH) using a μ2-oxo-bridged, bimetallic [V2O4(acac)2] (1) (acac = acetylacetonate anion) complex as a precursor. The identity and the nuclearity of the product of grafting and of the subsequent oxidative treatment have been systematically studied by means of FT-IR, Raman, solid-state (SS) NMR, UV-vis DRS, EPR and EXAFS spectroscopies. We show that the grafting of 1 on the silica surface under a rigorous SOMC protocol and the subsequent oxidative thermal treatment lead exclusively to well-defined and isolated monovanadate species. The resulting material has been tested for the oxidative dehydrogenation of propane in a moderate temperature range (400-525 °C) and compared with that of silica-supported vanadium catalysts prepared by the standard impregnation technique. The experimental results show that the catalytic activity in propane ODH is strongly upgraded by the degree of isolation of the VOx species that can be achieved by employing the SOMC protocol. © 2016 American Chemical Society.

  8. Utility of a redox-active pyridine(diimine) chelate in facilitating two electron oxidative addition chemistry at uranium.

    Science.gov (United States)

    Kiernicki, John J; Fanwick, Phillip E; Bart, Suzanne C

    2014-08-01

    Exposure of the uranium(IV) complex, Cp(P)U((Mes)PDI(Me)) (1) ((Mes)PDI(Me) = 2,6-((Mes)N=CMe)2–C5H3N; Mes = 2,4,6-trimethylphenyl; Cp(P) = 1-(7,7-dimethylbenzyl)cyclopentadienyl), which contains a [(Mes)PDI(Me)](3−) chelate, to I2, Cl2, PhSeCl, and PhEEPh (E = S, Se, Te) results in oxidative addition to form the uranium(IV) family, Cp(P)U(XX′)((Mes)PDI(Me)) (X = X′ = I, Cl, EPh; X = SePh, X′ = Cl). Spectroscopic and structural studies support products with [(Mes)PDI(Me)](1−), indicating the reducing equivalents derive from this redox-active chelate.

  9. Experimentally calibrated computational chemistry of tryptophan hydroxylase: Trans influence, hydrogen-bonding, and 18-electron rule govern O-2-activation

    DEFF Research Database (Denmark)

    Haahr, Lærke Tvedebrink; Kepp, Kasper Planeta; Boesen, Jane

    2010-01-01

    ) and a peroxo intermediate with peroxide trans to glutamate (Pglu) were found to be consistent (0.57–0.59 mm/s) with experimental Mössbauer isomer shifts (0.55 mm/s) and had low computed free energies. The weaker trans influence of histidine is shown to give rise to a bent O2 coordination mode with O2 pointing...... with the experimental value (0.25 mm/s) which we propose as the structure of the hydroxylating intermediate, with the tryptophan substrate well located for further reaction 3.5 Å from the ferryl group. Based on the optimized transition states, the activation barriers for the two paths (glu and his) are similar, so...

  10. Searching for halo-alkalophilic proteases maintaining stability and activity in hydrophilic aprotic solvents as biocatalysts in carbohydrate chemistry

    DEFF Research Database (Denmark)

    Pedersen, Lars Haastrup; Mørkholt, Camilla Kær; Nielsen, Carsten Bue

    2012-01-01

    and other carbohydrates (1, 2). Therefore, we are searching for new bacterial halo-alkaline proteases from extreme environments in Denmark. So far we have identified a number of interesting isolates showing proteolytic activity at pH 7 and 10. Whole genome Illumina Hiseq 2000 amplicon sequencing, de novo...... assembly of the genome and automatic annotation of genes in the genome was carried out by RAST to find the genes responsible for protease production. The amino-acid sequence of the expressed proteolytic proteins was analyzed using tandem MS. The isolates identified so far belong to Bacillus sp. One...... of the interesting genomes with a total length of 4.1 Mb was assembled in 42 contigs with a total of 3070 known genes of which 39 are encoding for proteases (one serine endopeptidase). Another genome was assembled in 219 contigs with 4004 coding sequences and 2821 known genes of which 36 are encoding for proteases...

  11. Study on 1,3,5-triazine chemistry in dehydrocondensation: gauche effect on the generation of active triazinylammonium species.

    Science.gov (United States)

    Kunishima, Munetaka; Ujigawa, Takae; Nagaoka, Yoshie; Kawachi, Chiho; Hioki, Kazuhito; Shiro, Motoo

    2012-12-03

    The reaction of 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) with various nitrogen-containing compounds, particularly tertiary amines (tert-amines), has been studied for the preparation of 2-(4,6-dimethoxy-1,3,5-triazinyl)trialkylammonium salts [DMT-Am(s)]. DMT-Ams derived from aliphatic tert-amines exhibited activity for the dehydrocondensation between a carboxylic acid and an amine to form an amide in a model reaction. Based on a conformational analysis of DMT-Ams and tert-amines by NMR and X-ray diffraction methods, we concluded that a β-alkyl group maintained in a gauche relationship with the nitrogen lone pair of tert-amines significantly hinders the approach of CDMT to the nitrogen. Thus, trimethylamine and quinuclidine without such alkyl groups readily react with CDMT whereas triethylamine, possessing two or three such gauche β-alkyl groups in the stable conformations, does not react at all. The theory of "gauche β-alkyl group effect" proposed here provides useful guidelines for the preparation of DMT-Ams possessing various tertiary amine moieties. An investigation of the dehydrocondensation activity of tert-amines in a CDMT/tert-amine system that involves in situ generation of DMT-Am, showed that the gauche effect of the β-alkyl group becomes quite pronounced; the yield of the amide decreases significantly with tert-amines possessing an unavoidable gauche β-alkyl group. Thus, the tert-amine/CDMT systems are useful for judging whether tert-amines can readily react with CDMT without isolation of DMT-Ams.

  12. Chemistry Notes.

    Science.gov (United States)

    School Science Review, 1982

    1982-01-01

    Presents laboratory procedures, classroom materials/activities, and demonstrations, including: vapor pressure of liquid mixtures and Raoult's law; preparation/analysis of transition metal complexes of ethylammonium chloride; atomic structure display using a ZX81 (includes complete program listing); "pop-up" models of molecules and ions; reactions…

  13. CHINESE JOURNAL OF CHEMISTRY

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@Chinese Journal of Chemistry is an international journal published in English by the Chinese Chemical Society with its editorial office hosted by Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences.

  14. Advanced Chemistry Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Description/History: Chemistry laboratoryThe Advanced Chemistry Laboratory (ACL) is a unique facility designed for working with the most super toxic compounds known...

  15. Organometallic Chemistry of Molybdenum.

    Science.gov (United States)

    Lucas, C. Robert; Walsh, Kelly A.

    1987-01-01

    Suggests ways to avoid some of the problems students have learning the principles of organometallic chemistry. Provides a description of an experiment used in a third-year college chemistry laboratory on molybdenum. (TW)

  16. Environmental chemistry: Volume A

    Energy Technology Data Exchange (ETDEWEB)

    Yen, T.F.

    1999-08-01

    This is an extensive introduction to environmental chemistry for engineering and chemical professionals. The contents of Volume A include a brief review of basic chemistry prior to coverage of litho, atmo, hydro, pedo, and biospheres.

  17. Chemistry for Potters.

    Science.gov (United States)

    Denio, Allen A.

    1980-01-01

    Relates pottery making to chemistry by providing chemical information about clay, its origin, composition, properties, and changes that occur during firing; also describes glaze compositions, examples of redox chemistry, salt glazing, crystalline glazes, and problems in toxicity. (CS)

  18. An analysis of clinical consultation activities in clinical chemistry: implications for transformation and resident training in chemical pathology.

    Science.gov (United States)

    Schmidt, Robert L; Garcia, Christopher A; Panlener, Jeanne; Ashwood, Edward R; Jackson, Brian R; Hussong, Jerry W

    2014-05-01

    Clinical consultation is a key role of pathologists. Many have advocated that pathologists expand their consulting activities to improve laboratory utilization. Although many have suggested that residency programs need to provide experience in clinical consultation, little has been written on the nature of consultation or on the methods of training. To characterize the content of consultations and to describe training in consultation in chemical pathology within the residency program at the University of Utah, Salt Lake City. Retrospective review of the consultation database for the period between July 2011 and July 2012. Residents performed an average of 159 consultations a month covering 276 topics during the course of a year. Each topic involved 1 or more specific tests. Eighty percent of the topics received fewer than 12 calls. The most common topics involved virus testing (eg, hepatitis B virus, hepatitis C virus, human immunodeficiency virus). Consultations most often involved test interpretation (53%), selection (38%), and performance characteristics (21%). Twenty-seven percent of consultations involved 2 or more consultation categories (eg, interpretation and performance). Consultation calls in chemical pathology are widely distributed across topics. Consultations most often involve test interpretation and selection. Methods to assess the effectiveness of consultations and resident teaching should be devised.

  19. The Chemistry and Biological Activities of Natural Products from Northern African Plant Families: From Taccaceae to Zygophyllaceae.

    Science.gov (United States)

    Ntie-Kang, Fidele; Njume, Leonel E; Malange, Yvette I; Günther, Stefan; Sippl, Wolfgang; Yong, Joseph N

    2016-04-01

    Traditional medicinal practices have a profound influence on the daily lives of people living in developing countries, particularly in Africa, since the populations cannot generally afford the cost of Western medicines. We have undertaken to investigate the correlation between the uses of plants in Traditional African medicine and the biological activities of the derived natural products, with the aim to validate the use of traditional medicine in Northern African communities. The literature is covered for the period 1959-2015 and part III of this review series focuses on plant families with names beginning with letters T to Z. The authors have focused on curating data from journals in natural products and phytomedicine. Within each journal home page, a query search based on country name was conducted. All articles "hits" were then verified, one at a time, that the species was harvested within the Northern African geographical regions. The current data partly constitutes the bases for the development of the Northern African natural compounds database. The review discusses 284 plant-based natural compounds from 34 species and 11 families. It was observed that the ethnobotanical uses of less than 40 % of the plant species surveyed correlated with the bioactivities of compounds identified.

  20. Coordination chemistry of a pi-extended, rigid and redox-active tetrathiafulvalene-fused Schiff-base ligand.

    Science.gov (United States)

    Wu, Jin-Cai; Liu, Shi-Xia; Keene, Tony D; Neels, Antonia; Mereacre, Valeriu; Powell, Annie K; Decurtins, Silvio

    2008-04-21

    A pi-extended, redox-active tetradentate tetrathiafulvalene-fused salphen [salphen = N,N'-phenylenebis(salicylideneimine)] compound (L) was prepared via a direct Schiff-base condensation of the corresponding diamine-tetrathiafulvalene (TTF) precursor with salicylaldehyde. Its chelating coordination ability has been demonstrated by the formation of the corresponding transition metal complexes in the presence of M(OAc)2.nH2O (M = Co(II), Ni(II), Cu(II)) and FeCl3.6H2O. Three complexes have been characterized by single-crystal X-ray diffraction analysis showing that the TTF-salphen ligand coordinates to the metal ions in a planar mode through the nitrogen and oxygen atoms in a N2O2 cis-configuration. In the case of Fe(III), a dinuclear oxo-bridged Fe(III) complex is formed. These paramagnetic complexes are promising building blocks for the construction of dual functional materials due to their unique structural features (planarity and rigidity) as well as their inherent redox properties.

  1. Green chemistry: A tool in Pharmaceutical Chemistry

    Directory of Open Access Journals (Sweden)

    Smita Talaviya

    2012-07-01

    Full Text Available Green chemistry expresses an area of research developing from scientific discoveries about pollution awareness and it utilizes a set of principles that reduces or eliminates the use or generation of hazardous substances in all steps of particular synthesis or process. Chemists and medicinal scientists can greatly reduce the risk to human health and the environment by following all the valuable principles of green chemistry. The most simple and direct way to apply green chemistry in pharmaceuticals is to utilize eco-friendly, non-hazardous, reproducible and efficient solvents and catalysts in synthesis of drug molecules, drug intermediates and in researches involving synthetic chemistry. Microwave synthesis is also an important tool of green chemistry by being an energy efficient process.

  2. Organometallic frustrated Lewis pair chemistry.

    Science.gov (United States)

    Erker, Gerhard

    2011-08-07

    Frustrated Lewis pairs are playing an increasingly important role in organometallic chemistry. Examples are presented and discussed where organometallic systems themselves serve as the Lewis base or Lewis acid components in frustrated Lewis pair chemistry, mostly through their attached functional groups. Activation of dihydrogen takes place easily in many of these systems. This may lead to the generation of novel catalyst systems but also in many cases to the occurrence of specific reactions at the periphery of the organometallic frameworks. Increasingly, FLP reactions are used to carry out functional group conversions in organometallic systems under mild reaction conditions. The limits of typical FLP reactivity are explored with selected organometallic examples, a discussion that points toward new developments, such as the discovery of facile new 1,1-carboboration reactions. Learning more and more about the broad spectrum of frustrated Lewis pair chemistry helps us to find novel reactions and applications.

  3. A Profile of Pre-College Chemistry Teaching in Beirut

    Science.gov (United States)

    Ayoubi, Zalpha; BouJaoude, Saouma

    2006-01-01

    The purpose of this study was to answer the following questions: 1) How well prepared are chemistry teachers in terms of content and pedagogy, 2) What are chemistry teachers trying to accomplish in their teaching and what activities do they use to meet their objectives and 3) What are the barriers to effective chemistry teaching identified by…

  4. Organic chemistry experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mun, Seok Sik

    2005-02-15

    This book deals with organic chemistry experiments, it is divided five chapters, which have introduction, the way to write the experiment report and safety in the laboratory, basic experiment technic like recrystallization and extraction, a lot of organic chemistry experiments such as fischer esterification, ester hydrolysis, electrophilic aromatic substitution, aldol reaction, benzoin condensation, wittig reaction grignard reaction, epoxidation reaction and selective reduction. The last chapter introduces chemistry site on the internet and way to find out reference on chemistry.

  5. American Association for Clinical Chemistry

    Science.gov (United States)

    ... older adolescents and adults. Read more IN CLINICAL CHEMISTRY Eliminating Wild-Type DNA in Liquid Biopsies Researchers ... Online Harmonization.net Commission on Accreditation in Clinical Chemistry American Board of Clinical Chemistry Clinical Chemistry Trainee ...

  6. Green Chemistry and Education.

    Science.gov (United States)

    Hjeresen, Dennis L.; Schutt, David L.; Boese, Janet M.

    2000-01-01

    Many students today are profoundly interested in the sustainability of their world. Introduces Green Chemistry and its principles with teaching materials. Green Chemistry is the use of chemistry for pollution prevention and the design of chemical products and processes that are environmentally benign. (ASK)

  7. Chemistry and Art.

    Science.gov (United States)

    Berry, Martyn

    1999-01-01

    Describes a Chemistry and Art project developed for secondary students and teachers sponsored by the National Gallery and The Royal Society of Chemistry in the United Kingdom. Discusses aspects of the techniques used in creating five paintings as well as the chemistry involved in their making, deterioration, conservation, and restoration.…

  8. Green Chemistry and Education.

    Science.gov (United States)

    Hjeresen, Dennis L.; Schutt, David L.; Boese, Janet M.

    2000-01-01

    Many students today are profoundly interested in the sustainability of their world. Introduces Green Chemistry and its principles with teaching materials. Green Chemistry is the use of chemistry for pollution prevention and the design of chemical products and processes that are environmentally benign. (ASK)

  9. Physical chemistry of surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, A.

    1990-01-01

    This book covers surface chemistry and selected aspects f colloid chemistry. The text covers such areas as structure and thermodynamics of liquid interfaces; electrical aspects of surface chemistry; microscopy and spectroscopy of solid interfaces; nucleation; contact angle; adsorption from solution; friction and adhesion; lubrication; and chemisorption and catalysis.

  10. Crystal chemistry of amphiboles: implications for oxygen fugacity and water activity in lithospheric mantle beneath Victoria Land, Antarctica

    Science.gov (United States)

    Bonadiman, C.; Nazzareni, S.; Coltorti, M.; Comodi, P.; Giuli, G.; Faccini, B.

    2014-03-01

    is present in mantle peridotites, the application of oxy-amphibole equilibrium is preferred, because ol-opx-sp oxy-calibrations are not "sensitive" enough in recording the effects (if any) of amphibole in the peridotite matrix. Amphibole acts as the main H acceptor among the peridotite minerals and may prevent fluid circulation and buffer oxygen fugacity. The important conclusion of this study is that amphibole within the lithospheric mantle does not always means high water activity and oxidizing conditions.

  11. Complex Protostellar Chemistry

    Science.gov (United States)

    Nuth, Joseph A., III; Johnson, Natasha M.

    2012-01-01

    Two decades ago, our understanding of the chemistry in protostars was simple-matter either fell into the central star or was trapped in planetary-scale objects. Some minor chemical changes might occur as the dust and gas fell inward, but such effects were overwhelmed by the much larger scale processes that occurred even in bodies as small as asteroids. The chemistry that did occur in the nebula was relatively easy to model because the fall from the cold molecular cloud into the growing star was a one-way trip down a well-known temperature-pressure gradient; the only free variable was time. However, just over 10 years ago it was suggested that some material could be processed in the inner nebula, flow outward, and become incorporated into comets (1, 2). This outward flow was confirmed when the Stardust mission returned crystalline mineral fragments (3) from Comet Wild 2 that must have been processed close to the Sun before they were incorporated into the comet. In this week's Science Express, Ciesla and Sandford (4) demonstrate that even the outermost regions of the solar nebula can be a chemically active environment. Their finding could have consequences for the rest of the nebula.

  12. Complex Protostellar Chemistry

    Science.gov (United States)

    Nuth, Joseph A., III; Johnson, Natasha M.

    2012-01-01

    Two decades ago, our understanding of the chemistry in protostars was simple-matter either fell into the central star or was trapped in planetary-scale objects. Some minor chemical changes might occur as the dust and gas fell inward, but such effects were overwhelmed by the much larger scale processes that occurred even in bodies as small as asteroids. The chemistry that did occur in the nebula was relatively easy to model because the fall from the cold molecular cloud into the growing star was a one-way trip down a well-known temperature-pressure gradient; the only free variable was time. However, just over 10 years ago it was suggested that some material could be processed in the inner nebula, flow outward, and become incorporated into comets (1, 2). This outward flow was confirmed when the Stardust mission returned crystalline mineral fragments (3) from Comet Wild 2 that must have been processed close to the Sun before they were incorporated into the comet. In this week's Science Express, Ciesla and Sandford (4) demonstrate that even the outermost regions of the solar nebula can be a chemically active environment. Their finding could have consequences for the rest of the nebula.

  13. Presidential Green Chemistry Challenge: 1999 Academic Award

    Science.gov (United States)

    Presidential Green Chemistry Challenge 1999 award winner, Professor Terry Collins, developed a series of TAML oxidant activators that work with hydrogen peroxide to replace chlorine bleaches for paper making and laundry.

  14. Presidential Green Chemistry Challenge: 2008 Academic Award

    Science.gov (United States)

    Presidential Green Chemistry Challenge 2008 award winners, Professors Robert E. Maleczka, Jr. and Milton R. Smith, III, developed halogen-free, catalytic C-H activation/borylation to make aryl and heteroaryl boronic esters.

  15. Dapson in heterocyclic chemistry, part VIII: synthesis, molecular docking and anticancer activity of some novel sulfonylbiscompounds carrying biologically active 1,3-dihydropyridine, chromene and chromenopyridine moieties

    Directory of Open Access Journals (Sweden)

    Al-Said Mansour S

    2012-07-01

    Full Text Available Abstract Several new sulfonebiscompounds having a biologically active 1,2-dihydropyridine-2-one 3–19, acrylamide 20, chromene 21, 22 and chromenopyridine 23, 24 moieties were synthesized and evaluated as potential anticancer agents. The structures of the products were confirmed via elemental analyses and spectral data. The screening tests showed that many of the biscompounds obtained exhibited good anticancer activity against human breast cell line (MCF7 comparable to doxorubicin which was used as reference drug. Compounds 11, 17 and 24 showed IC50 values 35.40 μM, 29.86 μM and 30.99 μM, respectively. In order to elucidate the mechanism of action of the synthesized compounds as anticancer agents, docking on the active site of farnesyltransferase and arginine methyltransferase was also performed and good results were obtained.

  16. Surface chemistry essentials

    CERN Document Server

    Birdi, K S

    2013-01-01

    Surface chemistry plays an important role in everyday life, as the basis for many phenomena as well as technological applications. Common examples range from soap bubbles, foam, and raindrops to cosmetics, paint, adhesives, and pharmaceuticals. Additional areas that rely on surface chemistry include modern nanotechnology, medical diagnostics, and drug delivery. There is extensive literature on this subject, but most chemistry books only devote one or two chapters to it. Surface Chemistry Essentials fills a need for a reference that brings together the fundamental aspects of surface chemistry w

  17. The New Color of Chemistry: Green Chemistry

    Directory of Open Access Journals (Sweden)

    Zuhal GERÇEK

    2012-01-01

    Full Text Available Green chemistry which is the new application of chemistry rules provides solutions to problems that mankind is faced with climate changes, sustainable agriculture, energy, toxics, depletion of natural sources e.g. designing new chemicals and processes that production and utilization of hazardous matters. So, it is the indispensible tool for sustainable development. Current and future chemists should consider the human health and ecological issues in their professional life. In order to provide a solution for this requirement, green chemistry rules and under standings should be primarily taken in the university curriculum and at all educational levels.

  18. Octadecyl Chains Immobilized onto Hyaluronic Acid Coatings by Thiol-ene "Click Chemistry" Increase the Surface Antimicrobial Properties and Prevent Platelet Adhesion and Activation to Polyurethane.

    Science.gov (United States)

    Felgueiras, Helena P; Wang, L M; Ren, K F; Querido, M M; Jin, Q; Barbosa, M A; Ji, J; Martins, M C L

    2017-03-08

    Infection and thrombus formation are still the biggest challenges for the success of blood contact medical devices. This work aims the development of an antimicrobial and hemocompatible biomaterial coating through which selective binding of albumin (passivant protein) from the bloodstream is promoted and, thus, adsorption of other proteins responsible for bacterial adhesion and thrombus formation can be prevented. Polyurethane (PU) films were coated with hyaluronic acid, an antifouling agent, that was previously modified with thiol groups (HA-SH), using polydopamine as the binding agent. Octadecyl acrylate (C18) was used to attract albumin since it resembles the circulating free fatty acids and albumin is a fatty acid transporter. Thiol-ene "click chemistry" was explored for C18 immobilization on HA-SH through a covalent bond between the thiol groups from the HA and the alkene groups from the C18 chains. Surfaces were prepared with different C18 concentrations (0, 5, 10, and 20%) and successful immobilization was demonstrated by scanning electron microscopy (SEM), water contact angle determinations, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The ability of surfaces to bind albumin selectively was determined by quartz crystal microbalance with dissipation (QCM-D). Albumin adsorption increased in response to the hydrophobic nature of the surfaces, which augmented with C18 saturation. HA-SH coating reduced albumin adsorption to PU. C18 immobilized onto HA-SH at 5% promoted selective binding of albumin, decreased Staphylococcus aureus adhesion and prevented platelet adhesion and activation to PU in the presence of human plasma. C18/HA-SH coating was established as an innovative and promising strategy to improve the antimicrobial properties and hemocompatibility of any blood contact medical device.

  19. FIGAERO ToF CIMS measurements of chlorine photochemical activation by nitryl chloride chemistry at a semi-rural site in Beijing

    Science.gov (United States)

    Le Breton, Michael; Hallquist, Åsa M.; Kant Pathak, Ravi; Simpson, David; Wang, Yujue; Zheng, Jing; Yang, Yudong; Shang, Dongjie; Wang, Haichao; Lu, Keding; Guo, Song; Hu, Min; Hallquist, Mattias

    2017-04-01

    implemented into steady state calculations using the Master Chemical Mechanism (MCM) to assess how the daytime activation of chlorine competes with OH as a dominant oxidant in this heavily polluted region. The reactions of atomic chlorine with VOCs are traced and assessed via the gas and particle phase measurements of chlorinated VOCs and supporting Proton Transfer Reaction Mass Spectrometer (PTR MS) VOC measurements. This provides the first high frequency measurements of unique tracers for chlorine atom chemistry, several of which are represented in the MCM, in both the gas and particle phase and enable the detailed assessment of their diurnal variation and importance for photochemical smog formation.

  20. WOMAN IN CHEMISTRY. JANE MARCET, A RELEVANT FIGURE IN CHEMISTRY EDUCATION

    Directory of Open Access Journals (Sweden)

    Johanna Camacho Gonzalez

    2015-12-01

    Full Text Available A historiographical study of Jane Marcet’s role in spreading chemistry knowledge to a wider audience in the 19th century is presented here. Her efforts to spread scientific knowledge were crucial to sharing the most important theories of chemistry among different audiences, particularly women and young people. Through her book, “Conversations on Chemistry,” which was published in several editions from 1806 to 1853, she contributed significantly to chemistry education. Despite controversy over the large number of editions, this text is a strong witness to the active participation of women in science. Her scientific rigor and contribution to narrative strategies in chemistry pedagogy have given Jane Marcet consideration not only as an important woman in the scientific community of England during the first half of the 19th century but also as a central figure in the early development of chemistry diffusion and education.

  1. Green Goggles: Designing and Teaching a General Chemistry Course to Nonmajors Using a Green Chemistry Approach

    Science.gov (United States)

    Prescott, Sarah

    2013-01-01

    A novel course using green chemistry as the context to teach general chemistry fundamentals was designed, implemented and is described here. The course design included an active learning approach, with major course graded components including a weekly blog entry, exams, and a semester project that was disseminated by wiki and a public symposium.…

  2. Green Goggles: Designing and Teaching a General Chemistry Course to Nonmajors Using a Green Chemistry Approach

    Science.gov (United States)

    Prescott, Sarah

    2013-01-01

    A novel course using green chemistry as the context to teach general chemistry fundamentals was designed, implemented and is described here. The course design included an active learning approach, with major course graded components including a weekly blog entry, exams, and a semester project that was disseminated by wiki and a public symposium.…

  3. Advances in analytical chemistry

    Science.gov (United States)

    Arendale, W. F.; Congo, Richard T.; Nielsen, Bruce J.

    1991-01-01

    Implementation of computer programs based on multivariate statistical algorithms makes possible obtaining reliable information from long data vectors that contain large amounts of extraneous information, for example, noise and/or analytes that we do not wish to control. Three examples are described. Each of these applications requires the use of techniques characteristic of modern analytical chemistry. The first example, using a quantitative or analytical model, describes the determination of the acid dissociation constant for 2,2'-pyridyl thiophene using archived data. The second example describes an investigation to determine the active biocidal species of iodine in aqueous solutions. The third example is taken from a research program directed toward advanced fiber-optic chemical sensors. The second and third examples require heuristic or empirical models.

  4. The New Color of Chemistry: Green Chemistry

    OpenAIRE

    Zuhal GERÇEK

    2012-01-01

    Green chemistry which is the new application of chemistry rules provides solutions to problems that mankind is faced with climate changes, sustainable agriculture, energy, toxics, depletion of natural sources e.g. designing new chemicals and processes that production and utilization of hazardous matters. So, it is the indispensible tool for sustainable development. Current and future chemists should consider the human health and ecological issues in their professional life. In order to provid...

  5. Whole Atmosphere Community Climate Model With Lower Ionospheric Chemistry: Improved Modeling of Nitric Acid and Active Chlorine During Energetic Particle Precipitation

    Science.gov (United States)

    Verronen, P. T.; Andersson, M. E.; Marsh, D. R.; Kovacs, T.; Plane, J. M. C.; Päivärinta, S. M.

    2016-12-01

    Energetic particle precipitation (EPP) and ion chemistry affect the neutral composition of the polar middle atmosphere. For example, production of odd nitrogen and odd hydrogen during EPP events can decrease ozone by tens of percent. However, the standard ion chemistry parameterizations used in atmospheric models neglect the effects on some important species, such as nitric acid. We present WACCM-D, a variant of the Whole Atmosphere Community Climate Model, which includes a set of lower ionosphere (D-region) chemistry: 307 reactions of 20 positive ions and 21 negative ions. Compared to the Sodankylä Ion and Neutral Chemistry (SIC), a state-of-the-art 1-D model of the D-region chemistry, WACCM-D represents the lower ionosphere well. Comparison of ion concentrations between the models shows that the WACCM-D bias is typically within ±10% or less below 70 km. At 70-90 km, when strong altitude gradients in ionization rates and/or ion concentrations exist, the bias can be larger for some ions but is still within tens of percent. We also compare WACCM-D results for the January 2005 solar proton event (SPE) to those from the standard WACCM and observations from the Aura/MLS and SCISAT/ACE-FTS instruments. The results indicate that WACCM-D improves the modeling of {HNO3}, {HCl}, {ClO}, {OH}, and {NOx} during the SPE. For example, Northern Hemispheric {HNO3} from WACCM-D shows an increase by two orders of magnitude at 40-70 km compared to WACCM, reaching 2.6 ppbv, in agreement with the observations. Based on our results, WACCM-D provides a state-of-the-art global representation of D-region ion chemistry and improves modeling of EPP atmospheric effects considerably.

  6. Presidential Green Chemistry Challenge: 2001 Small Business Award

    Science.gov (United States)

    Presidential Green Chemistry Challenge 2001 award winner, EDEN Bioscience, discovered and commercialized harpins: nontoxic, naturally occurring, biodegradable proteins that activate a plant's defense and growth mechanisms.

  7. Radiological and Environmental Research Division annual report: Fundamental Molecular Physics and Chemistry, October 1977-September 1978. [Summary of research activities at Argonne National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Rowland, R. E.; Inokuti, Mitio [eds.

    1978-01-01

    Research presented includes 32 papers, six of which have appeared previously in ERA, and 26 appear in this issue of ERA. Molecular physics and chemistry including photoionization, molecular properties, oscillator strengths, scattering, shape resonances, and photoelectrons are covered. A list of publications is included. (JFP)

  8. Medicinal Chemistry and Molecular Modeling: An Integration to Teach Drug Structure-Activity Relationship and the Molecular Basis of Drug Action

    Science.gov (United States)

    Carvalho, Ivone; Borges, Aurea D. L.; Bernardes, Lilian S. C.

    2005-01-01

    The use of computational chemistry and the protein data bank (PDB) to understand and predict the chemical and molecular basis involved in the drug-receptor interactions is discussed. A geometrical and chemical overview of the great structural similarity in the substrate and inhibitor is provided.

  9. Creating and Teaching a Web-Based, University-Level Introductory Chemistry Course that Incorporates Laboratory Exercises and Active Learning Pedagogies

    Science.gov (United States)

    Phipps, Linda R.

    2013-01-01

    An introductory, nonscience-majors chemistry course was converted to a Web-based course. The differences in student populations, teaching strategies, laboratory methods, and learning outcomes are described. Practical information is also given on the use of software and other online technology to implement course conversion. (Contains 2 tables.)

  10. Orbital interactions in chemistry

    CERN Document Server

    Albright, Thomas A; Whangbo, Myung-Hwan

    2013-01-01

    Explains the underlying structure that unites all disciplines in chemistry Now in its second edition, this book explores organic, organometallic, inorganic, solid state, and materials chemistry, demonstrating how common molecular orbital situations arise throughout the whole chemical spectrum. The authors explore the relationships that enable readers to grasp the theory that underlies and connects traditional fields of study within chemistry, thereby providing a conceptual framework with which to think about chemical structure and reactivity problems. Orbital Interactions

  11. Intermediate-energy nuclear chemistry workshop

    Energy Technology Data Exchange (ETDEWEB)

    Butler, G.W.; Giesler, G.C.; Liu, L.C.; Dropesky, B.J.; Knight, J.D.; Lucero, F.; Orth, C.J.

    1981-05-01

    This report contains the proceedings of the LAMPF Intermediate-Energy Nuclear Chemistry Workshop held in Los Alamos, New Mexico, June 23-27, 1980. The first two days of the Workshop were devoted to invited review talks highlighting current experimental and theoretical research activities in intermediate-energy nuclear chemistry and physics. Working panels representing major topic areas carried out indepth appraisals of present research and formulated recommendations for future research directions. The major topic areas were Pion-Nucleus Reactions, Nucleon-Nucleus Reactions and Nuclei Far from Stability, Mesonic Atoms, Exotic Interactions, New Theoretical Approaches, and New Experimental Techniques and New Nuclear Chemistry Facilities.

  12. Advances in quantum chemistry

    CERN Document Server

    Sabin, John R

    2013-01-01

    Advances in Quantum Chemistry presents surveys of current topics in this rapidly developing field that has emerged at the cross section of the historically established areas of mathematics, physics, chemistry, and biology. It features detailed reviews written by leading international researchers. This volume focuses on the theory of heavy ion physics in medicine.Advances in Quantum Chemistry presents surveys of current topics in this rapidly developing field that has emerged at the cross section of the historically established areas of mathematics, physics, chemistry, and biology. It features

  13. Science Update: Analytical Chemistry.

    Science.gov (United States)

    Worthy, Ward

    1980-01-01

    Briefly discusses new instrumentation in the field of analytical chemistry. Advances in liquid chromatography, photoacoustic spectroscopy, the use of lasers, and mass spectrometry are also discussed. (CS)

  14. Group theory and chemistry

    CERN Document Server

    Bishop, David M

    1993-01-01

    Group theoretical principles are an integral part of modern chemistry. Not only do they help account for a wide variety of chemical phenomena, they simplify quantum chemical calculations. Indeed, knowledge of their application to chemical problems is essential for students of chemistry. This complete, self-contained study, written for advanced undergraduate-level and graduate-level chemistry students, clearly and concisely introduces the subject of group theory and demonstrates its application to chemical problems.To assist chemistry students with the mathematics involved, Professor Bishop ha

  15. Green Chemistry Pedagogy

    Science.gov (United States)

    Kolopajlo, Larry

    2017-02-01

    This chapter attempts to show how the practice of chemistry teaching and learning is enriched by the incorporation of green chemistry (GC) into lectures and labs. To support this viewpoint, evidence from a wide range of published papers serve as a cogent argument that GC attracts and engages both science and nonscience students, enhances chemistry content knowledge, and improves the image of the field, while preparing the world for a sustainable future. Published pedagogy associated with green and sustainable chemistry is critically reviewed and discussed.

  16. Elements of environmental chemistry

    National Research Council Canada - National Science Library

    Hites, R. A; Raff, Jonathan D

    2012-01-01

    .... Extensively revised, updated, and expanded, this second edition includes new chapters on atmospheric chemistry, climate change, and polychlorinated biphenyls and dioxins, and brominated flame retardants...

  17. National Chemistry Week 2002: Chemistry Keeps Us Clean JCE Resources for Chemistry and Cleaning

    Science.gov (United States)

    Jacobsen, Erica K.

    2002-10-01

    The claims of cleaning products and personal care items are known to many. National Chemistry Week 2002 makes use of this familiar subject with its theme of "Chemistry Keeps Us Clean". A look back through the Journal of Chemical Education yields many articles connected to this theme. Students can make soap, test the properties of various household cleaners, find out how vacuum cleaners work, and more - all in the name of chemistry. This annotated bibliography collects the best that past issues of the Journal of Chemical Education have to offer for use with this year's National Chemistry Week. Each article has been characterized as a demonstration, experiment, activity, informational, or software/video item; several fit in more than one classification. The most recent articles are listed first. Also included is an evaluation as to which levels the article may serve. Articles that appeared adaptable to other levels, but are not designed explicitly for those levels, are labeled "poss. h.s." "poss. elem.", and so forth.

  18. Polymer Chemistry--An Elective in the New Leaving Chemistry Course: A Method of Teaching It

    Science.gov (United States)

    Lister, G.

    1972-01-01

    A scheme is suggested for teaching concepts of polymer chemistry. Laboratory activities are suggested for the major topics. Interrelationships of different industrial uses of polymers are emphasized during the course. (PS)

  19. From Metalloproteins to Coordination Chemistry: A Learning Exercise to Teach Transition Metal Chemistry

    Science.gov (United States)

    Reglinski, John; Graham, Duncan; Kennedy, Alan R.; Gibson, Lorraine T.

    2004-01-01

    An exercise is organized to reinforce the fundamental rules of coordination chemistry through a biological study of metalloproteins. The work, which is divided into four well-defined activities, involves a major application of computer databases to address chemical problems.

  20. 基于PTA量表的物理化学综合实践活动的实施与评价%The implementation and evaluation of integrative practical activities of physical chemistry

    Institute of Scientific and Technical Information of China (English)

    孙雅静; 赵雷洪

    2013-01-01

    物理化学作为一门化学理论课程,以抽象和繁杂的知识为主,成为学生学习生涯中的拦路虎。随着课程综合化在时代变迁中日益凸显的重要性,拟将综合实践活动引入物理化学的教学中,采用合作学习来组织教学,以期让学生能够在活动中轻松又高效地学习物理化学知识,并培养自身的综合能力。同时,尝试应用PTA量表法来评定学生在活动过程中的表现,方便教师对学生的学习情况进行科学有效的评价。%As a chemistry theory course with a great deal of abstract theoretical knowledge,physical chemistry is always an obstacle for students to study well. With the importance of course integration expressed as time goes by, attempts to combine physical chemistry with the integrative practical activities theory and utilizing the teaching strategy of cooperative learning,in order to let the students learn physical chemistry easily and efficiently and develop their comprehensive ability all around. In addition,it applies primary trait analysis(PTA)method to evaluate students′performance,so as to facilitate the teachers to carry out scientifical and effective evaluation.

  1. Mathematics and Chemistry

    Science.gov (United States)

    Henson, R.; Stumbles, A.

    1977-01-01

    The relationship between mathematics and chemistry has been changing rapidly in recent years. Some chemistry teachers have experienced difficulties in their teaching with the introduction of modern mathematics in the schools. Some suggestions for reinforcing the concepts and language of modern mathematics are put forth. (Author/MA)

  2. Movies in Chemistry Education

    Science.gov (United States)

    Pekdag, Bulent; Le Marechal, Jean-Francois

    2010-01-01

    This article reviews numerous studies on chemistry movies. Movies, or moving pictures, are important elements of multimedia and signify a privileged or motivating means of presenting knowledge. Studies on chemistry movies show that the first movie productions in this field were devoted to university lectures or documentaries. Shorter movies were…

  3. Physical Chemistry of Molecular

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ Established in 2009, the group consists of six researchers and more than 70 research assistants and graduate students from the CAS Key Laboratory of Molecular Nanostructures and Nanotechnologies at the CAS Institute of Chemistry.Its research focuses on the physical chemistry involved in molecular assembly, molecular nanostructures, functional nanomaterials and conceptual nano-devices.

  4. Exercises in Computational Chemistry

    DEFF Research Database (Denmark)

    Spanget-Larsen, Jens

    2016-01-01

    A selection of HyperChem© PC-exercises in computational chemistry. Answers to most questions are appended (Roskilde University 2014-16).......A selection of HyperChem© PC-exercises in computational chemistry. Answers to most questions are appended (Roskilde University 2014-16)....

  5. The Breath of Chemistry

    DEFF Research Database (Denmark)

    Josephsen, Jens

    The present preliminary text is a short thematic presentation in biological inorganic chemistry meant to illustrate general and inorganic (especially coordination) chemistry in biochemistry. The emphasis is on molecular models to explain features of the complicated mechanisms essential to breathing...

  6. Bioorganic and bioinorganic chemistry.

    Science.gov (United States)

    Constable, Edwin C; Housecroft, Catherine E; Creus, Marc; Gademann, Karl; Giese, Bernd; Ward, Thomas R; Woggon, Wolf D; Chougnet, Antoinette

    2010-01-01

    The interdisciplinary projects in bioinorganic and bioorganic chemistry of the Department of Chemistry, University of Basel led to the preparation of new systems that mimic biologically important processes and to the discovery of compounds from natural sources which are very promising with respect to medical applications. The advances in these areas are reported here.

  7. Exercises in Computational Chemistry

    DEFF Research Database (Denmark)

    Spanget-Larsen, Jens

    2016-01-01

    A selection of HyperChem© PC-exercises in computational chemistry. Answers to most questions are appended (Roskilde University 2014-16).......A selection of HyperChem© PC-exercises in computational chemistry. Answers to most questions are appended (Roskilde University 2014-16)....

  8. Chemistry in Microfluidic Channels

    Science.gov (United States)

    Chia, Matthew C.; Sweeney, Christina M.; Odom, Teri W.

    2011-01-01

    General chemistry introduces principles such as acid-base chemistry, mixing, and precipitation that are usually demonstrated in bulk solutions. In this laboratory experiment, we describe how chemical reactions can be performed in a microfluidic channel to show advanced concepts such as laminar fluid flow and controlled precipitation. Three sets of…

  9. Chemistry of americium

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, W.W.

    1976-01-01

    Essential features of the descriptive chemistry of americium are reviewed. Chapter titles are: discovery, atomic and nuclear properties, collateral reading, production and uses, chemistry in aqueous solution, metal, alloys, and compounds, and, recovery, separation, purification. Author and subject indexes are included. (JCB)

  10. Academic Position "Associate Professor in Chemistry Education" of the Department of Physical Chemistry, University of Sofia: Dr. Milena Kirova [In Bulgarian

    Directory of Open Access Journals (Sweden)

    B.V. Toshev

    2013-05-01

    Full Text Available This is a review of research activity of Dr. Milena Kirova who applies for the academic position “Associate Professor in Chemistry Education” at the Department of Physical Chemistry, University of Sofia.

  11. Biosynthetic inorganic chemistry.

    Science.gov (United States)

    Lu, Yi

    2006-08-25

    Inorganic chemistry and biology can benefit greatly from each other. Although synthetic and physical inorganic chemistry have been greatly successful in clarifying the role of metal ions in biological systems, the time may now be right to utilize biological systems to advance coordination chemistry. One such example is the use of small, stable, easy-to-make, and well-characterized proteins as ligands to synthesize novel inorganic compounds. This biosynthetic inorganic chemistry is possible thanks to a number of developments in biology. This review summarizes the progress in the synthesis of close models of complex metalloproteins, followed by a description of recent advances in using the approach for making novel compounds that are unprecedented in either inorganic chemistry or biology. The focus is mainly on synthetic "tricks" learned from biology, as well as novel structures and insights obtained. The advantages and disadvantages of this biosynthetic approach are discussed.

  12. Art in Chemistry; Chemistry in Art.

    Science.gov (United States)

    Greenberg, Barbara R.; Patterson, Dianne

    High school teachers are often challenged to motivate students who have little or no interest in a subject and are bored with traditional instruction. This unique book is designed to help educators make chemistry classes more interesting and links art curriculum to practical applications, integrating the two subjects through scores of hands-on…

  13. Korean Kimchi Chemistry: A Multicultural Chemistry Connection

    Science.gov (United States)

    Murfin, Brian

    2009-01-01

    Connecting science with different cultures is one way to interest students in science, to relate science to their lives, and at the same time to broaden their horizons in a variety of ways. In the lesson described here, students make kimchi, a delicious and popular Korean dish that can be used to explore many important chemistry concepts,…

  14. Making Data Management Accessible in the Undergraduate Chemistry Curriculum

    Science.gov (United States)

    Reisner, Barbara A.; Vaughan, K. T. L.; Shorish, Yasmeen L.

    2014-01-01

    In the age of "big data" science, data management is becoming a key information literacy skill for chemistry professionals. To introduce this skill in the undergraduate chemistry major, an activity has been developed to familiarize undergraduates with data management. In this activity, students rename and organize cards that represent…

  15. MACTLAC—Supporting Liberal Arts Chemistry Faculty

    Science.gov (United States)

    Muyskens, Mark

    2002-06-01

    This association report describes the Midwestern Association of Chemistry Teachers in Liberal Arts Colleges, or MACTLAC. The unique service of this organization is that it provides a forum for discussing issues related to teaching chemistry and the support of chemistry teachers through networking with colleagues from different colleges. The association serves chemistry teachers at private liberal arts colleges in seven Midwestern states—Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, and Wisconsin. The primary function of the organization is to arrange for a single, high quality meeting per year. It also provides a placement service, and accomplishes some activities through ad hoc committees. A brief description of the organizational structure and its annual meeting is given.

  16. Assessing the impact of integrating POGIL in Elementary Organic Chemistry

    Science.gov (United States)

    Shatila, Ahmad

    Organic chemistry is a difficult subject to teach especially to non-chemistry majors. CHE 251, Elementary Organic Chemistry, is an introductory course in organic chemistry given to non-chemistry majors. It is usually taught the traditional way using lectures as the main method of presentation. In the fall of 2006, POGIL (Process Oriented Guided Inquiry Learning) activities were introduced in this course. POGIL is a program that integrates guided inquiry and cooperative learning in chemistry education. The purpose of this research study was to determine the effect of using POGIL activities in elementary organic chemistry. CHE 251, Elementary Organic Chemistry, was taught using a mixture of traditional teaching, lecturing, and POGIL activities. This was assessed by looking at the effect of using POGIL activities on student achievement. Furthermore, the study investigated possible effects of POGIL activities on students' attitudes toward chemistry. Archival data on 28 students enrolled in the fall 2004 semester were used in this study. In addition, 27 students enrolled in the 2006 semester participated in the study by completing an attitudinal survey that was developed by the researcher. Finally, 9 students enrolled in the 2006 semester were interviewed to give additional insight to the study. The quantitative data concerning achievement revealed no significant difference between groups, students who used POGIL did not differ from students who did not. Further, the quantitative data concerning confidence levels of students in understanding and applying organic chemistry before and after going through the POGIL activities revealed no significant difference. This study showed that students in general (88.8% of surveyed students) liked POGIL activities and preferred them over lecturing. Students thought that POGIL activities helped them better understand and learn chemistry. Furthermore, students acknowledged the benefits of guided inquiry and cooperative learning, the

  17. Moderator Chemistry Program

    Energy Technology Data Exchange (ETDEWEB)

    Dewitt, L.V.; Gibbs, A.; Lambert, D.P.; Bohrer, S.R.; Fanning, R.L.; Houston, M.W.; Stinson, S.L.; Deible, R.W.; Abdel-Khalik, S.I.

    1990-11-01

    Over the past fifteen months, the Systems Chemistry Group of the Reactor Engineering Department has undertaken a comprehensive study of the Department`s moderator chemistry program at Savannah River Site (SRS). An internal review was developed to formalize and document this program. Objectives were as outlined in a mission statement and action plan. In addition to the mission statement and action plan, nine separate task reports have been issued during the course of this study. Each of these task reports is included in this document as a chapter. This document is an organized compilation of the individual reports issued by the Systems Chemistry Group in assessment of SRS moderator chemistry to determine if there were significant gaps in the program as ft existed in October, 1989. While these reviews found no significant gaps in that mode of operation, or any items that adversely affected safety, items were identified that could be improved. Many of the items have already been dear with or are in the process of completion under this Moderator Chemistry Program and other Reactor Restart programs. A complete list of the items of improvement found under this assessment is found in Chapter 9, along with a proposed time table for correcting remaining items that can be improved for the chemistry program of SRS reactors. An additional external review of the moderator chemistry processes, recommendations, and responses to/from the Reactor Corrosion Mitigation Committee is included as Appendix to this compilation.

  18. Moderator Chemistry Program

    Energy Technology Data Exchange (ETDEWEB)

    Dewitt, L.V.; Gibbs, A.; Lambert, D.P.; Bohrer, S.R.; Fanning, R.L.; Houston, M.W.; Stinson, S.L.; Deible, R.W.; Abdel-Khalik, S.I.

    1990-11-01

    Over the past fifteen months, the Systems Chemistry Group of the Reactor Engineering Department has undertaken a comprehensive study of the Department's moderator chemistry program at Savannah River Site (SRS). An internal review was developed to formalize and document this program. Objectives were as outlined in a mission statement and action plan. In addition to the mission statement and action plan, nine separate task reports have been issued during the course of this study. Each of these task reports is included in this document as a chapter. This document is an organized compilation of the individual reports issued by the Systems Chemistry Group in assessment of SRS moderator chemistry to determine if there were significant gaps in the program as ft existed in October, 1989. While these reviews found no significant gaps in that mode of operation, or any items that adversely affected safety, items were identified that could be improved. Many of the items have already been dear with or are in the process of completion under this Moderator Chemistry Program and other Reactor Restart programs. A complete list of the items of improvement found under this assessment is found in Chapter 9, along with a proposed time table for correcting remaining items that can be improved for the chemistry program of SRS reactors. An additional external review of the moderator chemistry processes, recommendations, and responses to/from the Reactor Corrosion Mitigation Committee is included as Appendix to this compilation.

  19. Mathematics for physical chemistry

    CERN Document Server

    Mortimer, Robert G

    2013-01-01

    Mathematics for Physical Chemistry is the ideal supplementary text for practicing chemists and students who want to sharpen their mathematics skills while enrolled in general through physical chemistry courses. This book specifically emphasizes the use of mathematics in the context of physical chemistry, as opposed to being simply a mathematics text. This 4e includes new exercises in each chapter that provide practice in a technique immediately after discussion or example and encourage self-study. The early chapters are constructed around a sequence of mathematical topics, wit

  20. Gas phase ion chemistry

    CERN Document Server

    Bowers, Michael T

    1979-01-01

    Gas Phase Ion Chemistry, Volume 1 covers papers on the advances of gas phase ion chemistry. The book discusses the advances in flow tubes and the measurement of ion-molecule rate coefficients and product distributions; the ion chemistry of the earth's atmosphere; and the classical ion-molecule collision theory. The text also describes statistical methods in reaction dynamics; the state selection by photoion-photoelectron coincidence; and the effects of temperature and pressure in the kinetics of ion-molecule reactions. The energy distribution in the unimolecular decomposition of ions, as well

  1. Spatially Resolved Artificial Chemistry

    DEFF Research Database (Denmark)

    Fellermann, Harold

    2009-01-01

    Although spatial structures can play a crucial role in chemical systems and can drastically alter the outcome of reactions, the traditional framework of artificial chemistry is a well-stirred tank reactor with no spatial representation in mind. Advanced method development in physical chemistry has...... made a class of models accessible to the realms of artificial chemistry that represent reacting molecules in a coarse-grained fashion in continuous space. This chapter introduces the mathematical models of Brownian dynamics (BD) and dissipative particle dynamics (DPD) for molecular motion and reaction...

  2. Fluorine in medicinal chemistry.

    Science.gov (United States)

    Swallow, Steven

    2015-01-01

    Since its first use in the steroid field in the late 1950s, the use of fluorine in medicinal chemistry has become commonplace, with the small electronegative fluorine atom being a key part of the medicinal chemist's repertoire of substitutions used to modulate all aspects of molecular properties including potency, physical chemistry and pharmacokinetics. This review will highlight the special nature of fluorine, drawing from a survey of marketed fluorinated pharmaceuticals and the medicinal chemistry literature, to illustrate key concepts exploited by medicinal chemists in their attempts to optimize drug molecules. Some of the potential pitfalls in the use of fluorine will also be highlighted.

  3. Experiments in physical chemistry

    CERN Document Server

    Wilson, J M; Denaro, A R

    1968-01-01

    Experiments in Physical Chemistry, Second Edition provides a compilation of experiments concerning physical chemistry. This book illustrates the link between the theory and practice of physical chemistry. Organized into three parts, this edition begins with an overview of those experiments that generally have a simple theoretical background. Part II contains experiments that are associated with more advanced theory or more developed techniques, or which require a greater degree of experimental skill. Part III consists of experiments that are in the nature of investigations wherein these invest

  4. Atmospheric and aerosol chemistry

    Energy Technology Data Exchange (ETDEWEB)

    McNeill, V. Faye [Columbia Univ., New York, NY (United States). Dept. of Chemical Engineering; Ariya, Parisa A. (ed.) [McGill Univ. Montreal, QC (Canada). Dept. of Chemistry; McGill Univ. Montreal, QC (Canada). Dept. of Atmospheric and Oceanic Sciences

    2014-09-01

    This series presents critical reviews of the present position and future trends in modern chemical research. Short and concise reports on chemistry, each written by the world renowned experts. Still valid and useful after 5 or 10 years. More information as well as the electronic version of the whole content available at: springerlink.com. Christian George, Barbara D'Anna, Hartmut Herrmann, Christian Weller, Veronica Vaida, D. J. Donaldson, Thorsten Bartels-Rausch, Markus Ammann Emerging Areas in Atmospheric Photochemistry. Lisa Whalley, Daniel Stone, Dwayne Heard New Insights into the Tropospheric Oxidation of Isoprene: Combining Field Measurements, Laboratory Studies, Chemical Modelling and Quantum Theory. Neil M. Donahue, Allen L. Robinson, Erica R. Trump, Ilona Riipinen, Jesse H. Kroll Volatility and Aging of Atmospheric Organic Aerosol. P. A. Ariya, G. Kos, R. Mortazavi, E. D. Hudson, V. Kanthasamy, N. Eltouny, J. Sun, C. Wilde Bio-Organic Materials in the Atmosphere and Snow: Measurement and Characterization V. Faye McNeill, Neha Sareen, Allison N. Schwier Surface-Active Organics in Atmospheric Aerosols.

  5. Atmospheric chemistry in volcanic plumes.

    Science.gov (United States)

    von Glasow, Roland

    2010-04-13

    Recent field observations have shown that the atmospheric plumes of quiescently degassing volcanoes are chemically very active, pointing to the role of chemical cycles involving halogen species and heterogeneous reactions on aerosol particles that have previously been unexplored for this type of volcanic plumes. Key features of these measurements can be reproduced by numerical models such as the one employed in this study. The model shows sustained high levels of reactive bromine in the plume, leading to extensive ozone destruction, that, depending on plume dispersal, can be maintained for several days. The very high concentrations of sulfur dioxide in the volcanic plume reduces the lifetime of the OH radical drastically, so that it is virtually absent in the volcanic plume. This would imply an increased lifetime of methane in volcanic plumes, unless reactive chlorine chemistry in the plume is strong enough to offset the lack of OH chemistry. A further effect of bromine chemistry in addition to ozone destruction shown by the model studies presented here, is the oxidation of mercury. This relates to mercury that has been coemitted with bromine from the volcano but also to background atmospheric mercury. The rapid oxidation of mercury implies a drastically reduced atmospheric lifetime of mercury so that the contribution of volcanic mercury to the atmospheric background might be less than previously thought. However, the implications, especially health and environmental effects due to deposition, might be substantial and warrant further studies, especially field measurements to test this hypothesis.

  6. Department of Nuclear Physical Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Mikulski, J. [Institute of Nuclear Physics, Cracow (Poland)

    1992-12-31

    The research program at the Department of Nuclear Physical Chemistry of the Niewodniczanski Institute of Nuclear Physics is described. The Department consist of three laboratories. First - Laboratory of Physical Chemistry of Separation Processes on which the activity is concentrated on separation of radioactive isotopes from particle bombarded target. The main interest is production and separation of neutron deficient isotopes for medical diagnostic and therapy. The investigation program includes measurements of nuclear reaction cross sections,, band resolution technique, preparation of radioactive sources, detection of non-radioactive trace elements. An independent project on desulphurization of flue gases is also carried out in the Laboratory. In the second one - Laboratory of Chemistry and Radiochemistry - the systematic studies of physicochemical properties of transition elements in solutions are carried out. The results of the performed experiments were used for the elaboration of new rapid and selective methods for various elements. Some of these results have been applied for separation of trans actinide elements at U-400 cyclotron of JINR Dubna. The third one laboratory - Environmental Radioactivity Laboratory -conducts continuous monitoring of radioactivity contamination of atmosphere. The investigation of different radionuclides concentration in natural environment, mainly in the forest had been carried out. (author).

  7. Department of Nuclear Physical Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Mikulski, J. [Institute of Nuclear Physics, Cracow (Poland)

    1994-12-31

    The research program at the Department of Nuclear Physical Chemistry of the Niewodniczanski Institute of Nuclear Physics is described. The Department consist of three laboratories. First - Laboratory of Physical Chemistry of Separation Processes on which the activity is concentrated on production and separation of neutron deficient isotopes for medical diagnostic. Recently, the main interest was in {sup 111} In which is a promising tracer for cancer diagnostic. To increase the effectiveness of production of indium {sup 111} In the reaction with deuterons on the enriched cadmium target was carried out instead of the previously used one with alpha particles on natural silver. In the second one - Laboratory of Chemistry and Radiochemistry - the systematic studies of physicochemical properties of transition elements in solutions are carried out. The results of the performed experiments were used for the elaboration of new rapid and selective methods for various elements. Some of these results have been applied for separation of trans actinide elements at U-400 cyclotron of JINR Dubna. The third one laboratory -Environmental Radioactivity Laboratory - conducts continuous monitoring of radioactivity contamination of atmosphere. The investigation of different radionuclides concentration in natural environment, mainly in the forest had been carried out.

  8. Annual Report of Institute of Nuclear Chemistry and Technology 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-10-01

    The report is the collection of short communications being the review of the scientific activity of Institute of Nuclear Chemistry and Technology - Warsaw in 1997. The papers are gathered in several branches as follows: radiation chemistry and physics; radiochemistry, stable isotopes, nuclear analytical methods, chemistry in general; radiobiology; nuclear technologies and methods. The annual report of INCT-1997 contains also the general information about INCT as well as the full list of scientific papers being published by the staff in 1997

  9. Theoretical chemistry in Belgium a topical collection from theoretical chemistry accounts

    CERN Document Server

    Champagne, Benoît; De Proft, Frank; Leyssens, Tom

    2014-01-01

    Readers of this volume can take a tour around the research locations in Belgium which are active in theoretical and computational chemistry. Selected researchers from Belgium present research highlights of their work. Originally published in the journal Theoretical Chemistry Accounts, these outstanding contributions are now available in a hardcover print format. This volume will be of benefit in particular to those research groups and libraries that have chosen to have only electronic access to the journal. It also provides valuable content for all researchers in theoretical chemistry.

  10. Enzymes in Analytical Chemistry.

    Science.gov (United States)

    Fishman, Myer M.

    1980-01-01

    Presents tabular information concerning recent research in the field of enzymes in analytic chemistry, with methods, substrate or reaction catalyzed, assay, comments and references listed. The table refers to 128 references. Also listed are 13 general citations. (CS)

  11. Beauty in chemistry

    Directory of Open Access Journals (Sweden)

    Peter Atkins

    2006-03-01

    Full Text Available Though hard going for the general reader and highly personal in its selectivity, Elegant Solutions: Ten Beautiful Experiments in Chemistry provides reflections of a thoughtful author that will delight chemists

  12. Chemistry at large

    Directory of Open Access Journals (Sweden)

    Jeremy. K.M. Sanders

    2007-06-01

    Full Text Available A new book introduces young researchers to supramolecular chemistry, starting from the basics and working up to the more complicated aspects of the topic. While the text is inspiring for new graduates, it lacks a critical view.

  13. Microfluidics in inorganic chemistry.

    Science.gov (United States)

    Abou-Hassan, Ali; Sandre, Olivier; Cabuil, Valérie

    2010-08-23

    The application of microfluidics in chemistry has gained significant importance in the recent years. Miniaturized chemistry platforms provide controlled fluid transport, rapid chemical reactions, and cost-saving advantages over conventional reactors. The advantages of microfluidics have been clearly established in the field of analytical and bioanalytical sciences and in the field of organic synthesis. It is less true in the field of inorganic chemistry and materials science; however in inorganic chemistry it has mostly been used for the separation and selective extraction of metal ions. Microfluidics has been used in materials science mainly for the improvement of nanoparticle synthesis, namely metal, metal oxide, and semiconductor nanoparticles. Microfluidic devices can also be used for the formulation of more advanced and sophisticated inorganic materials or hybrids.

  14. Uncertainty in chemistry.

    Science.gov (United States)

    Menger, Fredric M

    2010-09-01

    It might come as a disappointment to some chemists, but just as there are uncertainties in physics and mathematics, there are some chemistry questions we may never know the answer to either, suggests Fredric M. Menger.

  15. Indicators: Soil Chemistry

    Science.gov (United States)

    The chemical makeup of the soil can provide information on wetland condition, wetland water quality and services being provided by the wetland ecosystem. Analyzing soil chemistry reveals if the soil is contaminated with a toxic chemical or heavy metal.

  16. Chemistry for Kids.

    Science.gov (United States)

    Sato, Sanae; Majoros, Bela

    1988-01-01

    Reports two methods for interesting children in chemistry. Describes a method for producing large soap bubbles and films for study. Examines the use of simple stories to explain common chemical concepts with example given. Lists titles of available stories. (ML)

  17. Supplemental instruction in chemistry

    Science.gov (United States)

    Lundeberg, Mary A.

    This study was designed to measure some effects of supplemental instruction in chemistry. Supplemental instruction is a peer-led cooperative learning program that encourages students to develop conceptual understanding by articulating both understandings and misconceptions in a think-aloud fashion. Supplemental instruction was offered three hours weekly outside of class and lab time for students in four classes of General Organic and Biological Chemistry. Over a two-year period 108 students volunteered to participate in this program; 45 students did not participate. As measured by final grades in chemistry and responses to a questionnaire, supplemental instruction was effective in increasing students' achievement in chemistry. Further research is needed to determine the in-depth effects of supplemental instruction on students' learning, problem solving, and self-esteem.

  18. Water Chemistry: Seeking Information

    Science.gov (United States)

    Delfino, Joseph J.

    1977-01-01

    A survey of the available literature in water chemistry is presented. Materials surveyed include: texts, reference books, bibliographic resources, journals, American Chemical Society publications, proceedings, unpublished articles, and reports. (BT)

  19. Making a Natural Product Chemistry Course Meaningful with a Mini Project Laboratory

    Science.gov (United States)

    Hakim, Aliefman; Liliasari; Kadarohman, Asep; Syah, Yana Maolana

    2016-01-01

    This paper discusses laboratory activities that can improve the meaningfulness of natural product chemistry course. These laboratory activities can be useful for students from many different disciplines including chemistry, pharmacy, and medicine. Students at the third-year undergraduate level of chemistry education undertake the project to…

  20. Impact of surface chemistry

    OpenAIRE

    2010-01-01

    The applications of molecular surface chemistry in heterogeneous catalyst technology, semiconductor-based technology, medical technology, anticorrosion and lubricant technology, and nanotechnology are highlighted in this perspective. The evolution of surface chemistry at the molecular level is reviewed, and the key roles of surface instrumentation developments for in situ studies of the gas–solid, liquid–solid, and solid–solid interfaces under reaction conditions are emphasized.

  1. Impact of surface chemistry

    Science.gov (United States)

    Somorjai, Gabor A.; Li, Yimin

    2011-01-01

    The applications of molecular surface chemistry in heterogeneous catalyst technology, semiconductor-based technology, medical technology, anticorrosion and lubricant technology, and nanotechnology are highlighted in this perspective. The evolution of surface chemistry at the molecular level is reviewed, and the key roles of surface instrumentation developments for in situ studies of the gas–solid, liquid–solid, and solid–solid interfaces under reaction conditions are emphasized. PMID:20880833

  2. Applications of supramolecular chemistry

    CERN Document Server

    Schneider, Hans-Jörg

    2012-01-01

    ""The time is ripe for the present volume, which gathers thorough presentations of the numerous actually realized or potentially accessible applications of supramolecular chemistry by a number of the leading figures in the field. The variety of topics covered is witness to the diversity of the approaches and the areas of implementation…a broad and timely panorama of the field assembling an eminent roster of contributors.""-Jean-Marie Lehn, 1987 Noble Prize Winner in Chemistry

  3. Gas phase ion chemistry

    CERN Document Server

    Bowers, Michael T

    1979-01-01

    Gas Phase Ion Chemistry, Volume 2 covers the advances in gas phase ion chemistry. The book discusses the stabilities of positive ions from equilibrium gas-phase basicity measurements; the experimental methods used to determine molecular electron affinities, specifically photoelectron spectroscopy, photodetachment spectroscopy, charge transfer, and collisional ionization; and the gas-phase acidity scale. The text also describes the basis of the technique of chemical ionization mass spectrometry; the energetics and mechanisms of unimolecular reactions of positive ions; and the photodissociation

  4. EPA Environmental Chemistry Laboratory

    Science.gov (United States)

    1993-01-01

    The Environmental Protection Agency's (EPA) Chemistry Laboratory (ECL) is a national program laboratory specializing in residue chemistry analysis under the jurisdiction of the EPA's Office of Pesticide Programs in Washington, D.C. At Stennis Space Center, the laboratory's work supports many federal anti-pollution laws. The laboratory analyzes environmental and human samples to determine the presence and amount of agricultural chemicals and related substances. Pictured, ECL chemists analyze environmental and human samples for the presence of pesticides and other pollutants.

  5. Click chemistry with DNA

    OpenAIRE

    El-Sagheer, Afaf H.; Brown, Tom

    2010-01-01

    The advent of click chemistry has led to an influx of new ideas in the nucleic acids field. The copper catalysed alkyne–azide cycloaddition (CuAAC) reaction is the method of choice for DNA click chemistry due to its remarkable efficiency. It has been used to label oligonucleotides with fluorescent dyes, sugars, peptides and other reporter groups, to cyclise DNA, to synthesise DNA catenanes, to join oligonucleotides to PNA, and to produce analogues of DNA with modified nucleobases and backbone...

  6. Forensic Chemistry Training

    OpenAIRE

    GERÇEK, Zuhal

    2012-01-01

    Increasing the types of terrorism and crime nowadays, the importance of the forensic sciences can be bett er understood. Forensic science is the application of the wide spectrum of science to answer the question of legal system. It contains the application of the principles, techniques and methods of basic sciences and its main aim is the determination of the physical facts which are important in legal situations. Forensic chemistry is the branch of chemistry which performs the chemical analy...

  7. Fundamentals of quantum chemistry

    CERN Document Server

    House, J E

    2004-01-01

    An introduction to the principles of quantum mechanics needed in physical chemistry. Mathematical tools are presented and developed as needed and only basic calculus, chemistry, and physics is assumed. Applications include atomic and molecular structure, spectroscopy, alpha decay, tunneling, and superconductivity. New edition includes sections on perturbation theory, orbital symmetry of diatomic molecules, the Huckel MO method and Woodward/Hoffman rules as well as a new chapter on SCF and Hartree-Fock methods. * This revised text clearly presents basic q

  8. Analytical Chemistry Division annual progress report: For period ending December 31, 1987

    Energy Technology Data Exchange (ETDEWEB)

    1988-05-01

    This report is divided into analytical spectroscopy; radioactive materials analysis; inorganic chemistry; organic chemistry; ORNL environmental programs; quality assurance, safety, and training; supplementary activities; and presentation of research results.

  9. China celebrates the International Year of Chemistry

    Institute of Scientific and Technical Information of China (English)

    XUE Zi-Ling

    2011-01-01

    China played an active role in the establishment of the International Year of Chemistry (IYC) 2011.Year-around programs in the country have celebrated the wonderful changes in our lives brought about by advances in chemical sciences.Chemists,chemical engineers,students,and the general public have used a range of interactive,entertaining,and educational activities around the country to celebrate the achievements of chemistry and its contributions to society.These have been reported on the IYC China websites at http://www.iyc2011.cn/(Chinese) and http://iyc2011.casad.cas.cn/iyc2011/(English) and newspaper and TV accounts.

  10. Photoredox Catalysis in Organic Chemistry

    Science.gov (United States)

    2016-01-01

    In recent years, photoredox catalysis has come to the forefront in organic chemistry as a powerful strategy for the activation of small molecules. In a general sense, these approaches rely on the ability of metal complexes and organic dyes to convert visible light into chemical energy by engaging in single-electron transfer with organic substrates, thereby generating reactive intermediates. In this Perspective, we highlight the unique ability of photoredox catalysis to expedite the development of completely new reaction mechanisms, with particular emphasis placed on multicatalytic strategies that enable the construction of challenging carbon–carbon and carbon–heteroatom bonds. PMID:27477076

  11. Photoredox Catalysis in Organic Chemistry.

    Science.gov (United States)

    Shaw, Megan H; Twilton, Jack; MacMillan, David W C

    2016-08-19

    In recent years, photoredox catalysis has come to the forefront in organic chemistry as a powerful strategy for the activation of small molecules. In a general sense, these approaches rely on the ability of metal complexes and organic dyes to convert visible light into chemical energy by engaging in single-electron transfer with organic substrates, thereby generating reactive intermediates. In this Perspective, we highlight the unique ability of photoredox catalysis to expedite the development of completely new reaction mechanisms, with particular emphasis placed on multicatalytic strategies that enable the construction of challenging carbon-carbon and carbon-heteroatom bonds.

  12. Organic chemistry of elemental phosphorus

    Energy Technology Data Exchange (ETDEWEB)

    Milyukov, V A; Budnikova, Yulia H; Sinyashin, Oleg G [A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Centre of the Russian Academy of Sciences, Kazan (Russian Federation)

    2005-09-30

    The principal achievements and the modern trends in the development of the chemistry of elemental phosphorus are analysed, described systematically and generalised. The possibilities and advantages of the preparation of organophosphorus compounds directly from white phosphorus are demonstrated. Attention is focused on the activation and transformation of elemental phosphorus in the coordination sphere of transition metal complexes. The mechanisms of the reactions of white phosphorus with nucleophilic and electrophilic reagents are discussed. Electrochemical approaches to the synthesis of organic phosphorus derivatives based on white phosphorus are considered.

  13. The Intelligent CAI System for Chemistry Based on Automated Reasoning

    Institute of Scientific and Technical Information of China (English)

    王晓京; 张景中

    1999-01-01

    A new type of intelligent CAI system for chemistry is developed in this paper based on automated reasoning with chemistry knowledge.The system has shown its ability to solve chemistry problems,to assist students and teachers in studies and instruction with the automated reasoning functions.Its open mode of the knowledge base and its unique style of the interface between the system and human provide more opportunities for the users to acquire living knowledge through active participation.The automated reasoning based on basic chemistry knowledge also opened a new approach to the information storage and management of the ICAI system for sciences.

  14. Reengineering Antibiotics to Combat Bacterial Resistance: Click Chemistry [1,2,3]-Triazole Vancomycin Dimers with Potent Activity against MRSA and VRE.

    Science.gov (United States)

    Silverman, Steven M; Moses, John E; Sharpless, K Barry

    2017-01-01

    Vancomycin has long been considered a drug of last resort. Its efficiency in treating multiple drug-resistant bacterial infections, particularly methicillin-resistant Staphylococcus aureus (MRSA), has had a profound effect on the treatment of life-threatening infections. However, the emergence of resistance to vancomycin is a cause for significant worldwide concern, prompting the urgent development of new effective treatments for antibiotic resistant bacterial infections. Harnessing the benefits of multivalency and cooperativity against vancomycin-resistant strains, we report a Click Chemistry approach towards reengineered vancomycin derivatives and the synthesis of a number of dimers with increased potency against MRSA and vancomycin resistant Enterococci (VRE; VanB). These semi-synthetic dimeric ligands were linked together with great efficiency using the powerful CuAAC reaction, demonstrating high levels of selectivity and purity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Cannabinoids: occurrence and medicinal chemistry.

    Science.gov (United States)

    Appendino, G; Chianese, G; Taglialatela-Scafati, O

    2011-01-01

    With an inventory of several hundreds secondary metabolites identified, Cannabis sativa L. (hemp) is one of the phytochemically best characterized plant species. The biomedical relevance of hemp undoubtedly underlies the wealth of data on its constituents and their biological activities, and cannabinoids, a class of unique meroterpenoids derived from the alkylation of an olivetollike alkyl resorcinol with a monoterpene unit, are the most typical constituents of Cannabis. In addition to the well-known psychotropic properties of Δ(9)-THC, cannabinoids have been reported to show potential in various fields of medicine, with the capacity to address unmet needs like the relief of chemotherapy-derived nausea and anorexia, and symptomatic mitigation of multiple sclerosis. Many of the potential therapeutic uses of cannabinoids are related to the interaction with (at least) two cannabinoid G-protein coupled receptors (CB1 and CB2). However, a number of activities, like the antibacterial or the antitumor properties are non totally dependent or fully independent from the interaction with these proteins. These pharmacological activities are particularly interesting since, in principle, they could be easily dissociated by the unwanted psychotropic effects. This review aims at giving readers a survey of the more recent advances in both phytochemistry of C. sativa, the medicinal chemistry of cannabinoids, and their distribution in plants, highlighting the impact that research in these hot fields could have for modern medicinal chemistry and pharmacology.

  16. Medicinal chemistry matters - a call for discipline in our discipline.

    Science.gov (United States)

    Johnstone, Craig

    2012-06-01

    Medicinal chemistry makes a vital contribution to small molecule drug discovery, and the quality of it contributes directly to research effectiveness as well as to downstream costs, speed and survival in development. In recent years, the discipline of medicinal chemistry has evolved and witnessed many noteworthy contributions that propose and offer potential improvements to medicinal chemistry practice; however, the impact of these ideas is limited by their acceptance and deployment into every-day activity and, as a result, the quality of medicinal chemistry remains variable. For the good of the industry and the medicinal chemistry discipline, there is a need to move from retrospective learning to prospective control of medicinal chemistry practice to improve cost effectiveness, probability of success and survival rates.

  17. Exploratory studies on coordination chemistry of a redox-active bridging ligand: synthesis, properties and solid state structures of the complexes.

    Science.gov (United States)

    Ran, Ying-Fen; Liu, Shi-Xia; Sereda, Olha; Neels, Antonia; Decurtins, Silvio

    2011-08-28

    The explorative coordination chemistry of the bridging ligand TTF-PPB is presented. Its strong binding ability to Co(II) and then to Ni(II) or Cu(II) in the presence of hexafluoroacetylacetonate (hfac(-)), forming new mono- and dinuclear complexes 1-3, is described. X-ray crystallographic studies have been conducted in the case of the free ligand TTF-PPB as well as its complexes [Co(TTF-PPB)(hfac)(2)] (1) and [Co(hfac)(2)(μ-TTF-PPB)Ni(hfac)(2)] (2). Each metal ion is bonded to two bidentate hfac(-) anions through their oxygen atoms and two nitrogen atoms of the PPB moiety with a distorted octahedral coordination geometry. Specifically, nitrogen donor atoms of TTF-PPB adopt a cis-coordination but not in the equatorial plane, which is quite rare. Electronic absorption, photoinduced intraligand charge transfer ((1)ILCT), and electrochemical behaviour of 1-3 have been investigated. UV-Vis spectroscopy shows very strong bands in the UV region consistent with ligand centred π-π* transitions and an intense broad band in the visible region corresponding to a spin-allowed π-π* (1)ILCT transition. Upon coordination, the (1)ILCT band is bathochromically shifted by 3100, 6100 and 5900 cm(-1) on going from 1 to 3. The electrochemical studies reveal that all of them undergo two reversible oxidation and one reversible reduction processes, ascribed to the successive oxidations of the TTF moiety and the reduction of the PPB unit, respectively. This journal is © The Royal Society of Chemistry 2011

  18. Recent advances in the chemistry and biology of pyridopyrimidines.

    Science.gov (United States)

    Buron, F; Mérour, J Y; Akssira, M; Guillaumet, G; Routier, S

    2015-05-05

    The interest in pyridopyrimidine cores for pharmaceutical products makes this scaffold a highly useful building block for organic chemistry. These derivatives have found applications in various areas of medicine such as anticancer, CNS, fungicidal, antiviral, anti-inflammatory, antimicrobial, and antibacterial therapies. This review mainly focuses on the progress achieved since 2004 in the chemistry and biological activity of pyridopyrimidines.

  19. Green Chemistry: Innovations for a Cleaner World. [Videotape].

    Science.gov (United States)

    American Chemical Society, Washington, DC.

    This video was developed through a cooperative agreement between the American Chemical Society (ACS)'s Education and International Activities Division and the U.S. Environmental Protection Agency's Green Chemistry Program, Office of Pollution Prevention and Toxics. "Green Chemistry" focuses on chemical products and processes that reduce or…

  20. Soil Studies: Applying Acid-Base Chemistry to Environmental Analysis.

    Science.gov (United States)

    West, Donna M.; Sterling, Donna R.

    2001-01-01

    Laboratory activities for chemistry students focus attention on the use of acid-base chemistry to examine environmental conditions. After using standard laboratory procedures to analyze soil and rainwater samples, students use web-based resources to interpret their findings. Uses CBL probes and graphing calculators to gather and analyze data and…

  1. Soil Studies: Applying Acid-Base Chemistry to Environmental Analysis.

    Science.gov (United States)

    West, Donna M.; Sterling, Donna R.

    2001-01-01

    Laboratory activities for chemistry students focus attention on the use of acid-base chemistry to examine environmental conditions. After using standard laboratory procedures to analyze soil and rainwater samples, students use web-based resources to interpret their findings. Uses CBL probes and graphing calculators to gather and analyze data and…

  2. Chemistry beyond positivism.

    Science.gov (United States)

    Brandt, Werner W

    2003-05-01

    Chemistry is often thought to be quite factual, and therefore might be considered close to the "positivist" ideal of a value-free science. A closer look, however, reveals that the field is coupled to the invisible realm of values, meanings, and purpose in various ways, and chemists interact with that realm loosely and unevenly. Tacit knowledge is one important locus of such interactions. We are concerned in this essay with two questions. What is the nature of the knowledge when we are in the early stages of discovery? and In what ways does the hidden reality we are seeking affect our search for an understanding of it? The first question is partly answered by Polanyi's theory of tacit knowledge, while the second one leads us to realize the limitations of our language when discussing "reality"-or certain chemical experimental results. A strictly positivist approach is of little use, but so is the opposite, the complete disregard of facts. The contrast between positivism and non-formulable aspects of scientific reasoning amounts to a paradox that needs to be analyzed and can lead to a "connected" chemistry. This in turn resembles networks described by Schweber and is more concerned than the chemistry "as it is" with aspects such as the image of chemistry, the challenges chemists face as citizens, and chemistry in liberal education.

  3. Building a Database for the Historical Analysis of the General Chemistry Curriculum Using ACS General Chemistry Exams as Artifacts

    Science.gov (United States)

    Luxford, Cynthia J.; Linenberger, Kimberly J.; Raker, Jeffrey R.; Baluyut, John Y.; Reed, Jessica J.; De Silva, Chamila; Holme, Thomas A.

    2015-01-01

    As a discipline, chemistry enjoys a unique position. While many academic areas prepared "cooperative examinations" in the 1930s, only chemistry maintained the activity within what has become the ACS Examinations Institute. As a result, the long-term existence of community-built, norm-referenced, standardized exams provides a historical…

  4. ADVANCES IN ORGANIC, BIOORGANIC AND NATURAL PRODUCTS CHEMISTRY IN THE INSTITUTE OF CHEMISTRY OF THE ACADEMY OF SCIENCES OF MOLDOVA

    Directory of Open Access Journals (Sweden)

    Pavel F. Vlad

    2009-06-01

    Full Text Available This overview deals with the advances in the investigation in the fi eld of organic, bioorganic and naturalproducts chemistry as well as the biologically active compounds in the Institute of Chemistry of the Academy of Sciences of Moldova.

  5. Building a Database for the Historical Analysis of the General Chemistry Curriculum Using ACS General Chemistry Exams as Artifacts

    Science.gov (United States)

    Luxford, Cynthia J.; Linenberger, Kimberly J.; Raker, Jeffrey R.; Baluyut, John Y.; Reed, Jessica J.; De Silva, Chamila; Holme, Thomas A.

    2015-01-01

    As a discipline, chemistry enjoys a unique position. While many academic areas prepared "cooperative examinations" in the 1930s, only chemistry maintained the activity within what has become the ACS Examinations Institute. As a result, the long-term existence of community-built, norm-referenced, standardized exams provides a historical…

  6. Mathematics for physical chemistry

    CERN Document Server

    Mortimer, Robert G

    2005-01-01

    Mathematics for Physical Chemistry, Third Edition, is the ideal text for students and physical chemists who want to sharpen their mathematics skills. It can help prepare the reader for an undergraduate course, serve as a supplementary text for use during a course, or serve as a reference for graduate students and practicing chemists. The text concentrates on applications instead of theory, and, although the emphasis is on physical chemistry, it can also be useful in general chemistry courses. The Third Edition includes new exercises in each chapter that provide practice in a technique immediately after discussion or example and encourage self-study. The first ten chapters are constructed around a sequence of mathematical topics, with a gradual progression into more advanced material. The final chapter discusses mathematical topics needed in the analysis of experimental data.* Numerous examples and problems interspersed throughout the presentations * Each extensive chapter contains a preview, objectives, and ...

  7. Air Composition and Chemistry

    Science.gov (United States)

    Brimblecombe, Peter

    1996-01-01

    This book is about the atmosphere and humanity's influence on it. For this new edition, Brimblecombe has rewritten and updated much of the book. In the early chapters, he discusses the geochemical, biological and maritime sources of the trace gases. Next, he examines the chemistry of atmospheric gases, suspended particles, and rainfall. After dealing with the natural atmosphere, he examines the sources of air pollution and its effects, with all scenarios updated from the last edition. Scenarios include decline in health, damage to plants and animals, indoor pollution, and acid rain. The final chapters, also revised, are concerned with the chemistry and evolution of the atmospheres of the planets of the solar system. Students with an interest in chemistry and the environmental sciences will find this book highly valuable.

  8. Reaction chemistry of cerium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    It is truly ironic that a synthetic organic chemist likely has far greater knowledge of the reaction chemistry of cerium(IV) than an inorganic colleague. Cerium(IV) reagents have long since been employed as oxidants in effecting a wide variety of organic transformations. Conversely, prior to the late 1980s, the number of well characterized cerium(IV) complexes did not extend past a handful of known species. Though in many other areas, interest in the molecular chemistry of the 4f-elements has undergone an explosive growth over the last twenty years, the chemistry of cerium(IV) has for the most part been overlooked. This report describes reactions of cerium complexes and structure.

  9. Reaction chemistry of cerium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    It is truly ironic that a synthetic organic chemist likely has far greater knowledge of the reaction chemistry of cerium(IV) than an inorganic colleague. Cerium(IV) reagents have long since been employed as oxidants in effecting a wide variety of organic transformations. Conversely, prior to the late 1980s, the number of well characterized cerium(IV) complexes did not extend past a handful of known species. Though in many other areas, interest in the molecular chemistry of the 4f-elements has undergone an explosive growth over the last twenty years, the chemistry of cerium(IV) has for the most part been overlooked. This report describes reactions of cerium complexes and structure.

  10. Spins in chemistry

    CERN Document Server

    McWeeny, Roy

    2004-01-01

    Originally delivered as a series of lectures, this volume systematically traces the evolution of the ""spin"" concept from its role in quantum mechanics to its assimilation into the field of chemistry. Author Roy McWeeny presents an in-depth illustration of the deductive methods of quantum theory and their application to spins in chemistry, following the path from the earliest concepts to the sophisticated physical methods employed in the investigation of molecular structure and properties. Starting with the origin and development of the spin concept, the text advances to an examination of sp

  11. Chemistry in microelectronics

    CERN Document Server

    Le Tiec, Yannick

    2013-01-01

    Microelectronics is a complex world where many sciences need to collaborate to create nano-objects: we need expertise in electronics, microelectronics, physics, optics and mechanics also crossing into chemistry, electrochemistry, as well as biology, biochemistry and medicine. Chemistry is involved in many fields from materials, chemicals, gases, liquids or salts, the basics of reactions and equilibrium, to the optimized cleaning of surfaces and selective etching of specific layers. In addition, over recent decades, the size of the transistors has been drastically reduced while the functionalit

  12. The philosophy of chemistry.

    Science.gov (United States)

    Schummer, Joachim

    2003-03-01

    Although chemistry is by far the largest scientific discipline according to any quantitative measure, it had, until recently, been virtually ignored by professional philosophers of science. They left both a vacuum and a one-sided picture of science tailored to physics. Since the early 1990s, the situation has changed drastically, such that philosophy of chemistry is now one of the most flourishing fields in the philosophy of science, like the philosophy of biology that emerged in the 1970s. This article narrates the development and provides a survey of the main topics and trends.

  13. Chemistry WebBook

    Science.gov (United States)

    SRD 69 NIST Chemistry WebBook (Web, free access)   The NIST Chemistry WebBook contains: Thermochemical data for over 7000 organic and small inorganic compounds; thermochemistry data for over 8000 reactions; IR spectra for over 16,000 compounds; mass spectra for over 33,000 compounds; UV/Vis spectra for over 1600 compounds; electronic and vibrational spectra for over 5000 compounds; constants of diatomic molecules(spectroscopic data) for over 600 compounds; ion energetics data for over 16,000 compounds; thermophysical property data for 74 fluids.

  14. Chemistry and lithography

    CERN Document Server

    Okoroanyanwu, Uzodinma

    2011-01-01

    This is a unique book, combining chemistry and physics with technology and history in a way that is both enlightening and lively. No other book in the field of lithography has as much breadth. Highly recommended for anyone interested in the broad application of chemistry to lithography. --Chris Mack, Gentleman Scientist. This book provides a comprehensive treatment of the chemical phenomena in lithography in a manner that is accessible to a wide readership. The book presents topics on the optical and charged particle physics practiced in lithography, with a broader view of how the marriage bet

  15. The chemistry of silicon

    CERN Document Server

    Rochow, E G; Emeléus, H J; Nyholm, Ronald

    1975-01-01

    Pergamon Texts in Organic Chemistry, Volume 9: The Chemistry of Silicon presents information essential in understanding the chemical properties of silicon. The book first covers the fundamental aspects of silicon, such as its nuclear, physical, and chemical properties. The text also details the history of silicon, its occurrence and distribution, and applications. Next, the selection enumerates the compounds and complexes of silicon, along with organosilicon compounds. The text will be of great interest to chemists and chemical engineers. Other researchers working on research study involving s

  16. Dynamic Combinatorial Chemistry

    DEFF Research Database (Denmark)

    Lisbjerg, Micke

    This thesis is divided into seven chapters, which can all be read individually. The first chapter, however, contains a general introduction to the chemistry used in the remaining six chapters, and it is therefore recommended to read chapter one before reading the other chapters. Chapter 1...... is a general introductory chapter for the whole thesis. The history and concepts of dynamic combinatorial chemistry are described, as are some of the new and intriguing results recently obtained. Finally, the properties of a broad range of hexameric macrocycles are described in detail. Chapter 2 gives...

  17. Dynamic Combinatorial Chemistry

    DEFF Research Database (Denmark)

    Lisbjerg, Micke

    This thesis is divided into seven chapters, which can all be read individually. The first chapter, however, contains a general introduction to the chemistry used in the remaining six chapters, and it is therefore recommended to read chapter one before reading the other chapters. Chapter 1...... is a general introductory chapter for the whole thesis. The history and concepts of dynamic combinatorial chemistry are described, as are some of the new and intriguing results recently obtained. Finally, the properties of a broad range of hexameric macrocycles are described in detail. Chapter 2 gives...

  18. Solvent effects in chemistry

    CERN Document Server

    Buncel, Erwin

    2015-01-01

    This book introduces the concepts, theory and experimental knowledge concerning solvent effects on the rate and equilibrium of chemical reactions of all kinds.  It begins with basic thermodynamics and kinetics, building on this foundation to demonstrate how a more detailed understanding of these effects may be used to aid in determination of reaction mechanisms, and to aid in planning syntheses. Consideration is given to theoretical calculations (quantum chemistry, molecular dynamics, etc.), to statistical methods (chemometrics), and to modern day concerns such as ""green"" chemistry, where ut

  19. Progress in physical chemistry

    CERN Document Server

    Hempelmann, Rolf

    2008-01-01

    Progress in Physical Chemistry is a collection of recent ""Review Articles"" published in the ""Zeitschrift für Physikalische Chemie"". The second volume of Progress in Physical Chemistry is a collection of thematically closely related minireview articles written by the members of the Collaborative Research Centre (SFB) 277 of the German Research Foundation (DFG). These articles are based on twelve years of intense coordinated research efforts. Central topics are the synthesis and the characterization of interface-dominated, i.e. nanostructured materials, mainly in the solid state but also as

  20. Algorithmic Strategies in Combinatorial Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    GOLDMAN,DEBORAH; ISTRAIL,SORIN; LANCIA,GIUSEPPE; PICCOLBONI,ANTONIO; WALENZ,BRIAN

    2000-08-01

    Combinatorial Chemistry is a powerful new technology in drug design and molecular recognition. It is a wet-laboratory methodology aimed at ``massively parallel'' screening of chemical compounds for the discovery of compounds that have a certain biological activity. The power of the method comes from the interaction between experimental design and computational modeling. Principles of ``rational'' drug design are used in the construction of combinatorial libraries to speed up the discovery of lead compounds with the desired biological activity. This paper presents algorithms, software development and computational complexity analysis for problems arising in the design of combinatorial libraries for drug discovery. The authors provide exact polynomial time algorithms and intractability results for several Inverse Problems-formulated as (chemical) graph reconstruction problems-related to the design of combinatorial libraries. These are the first rigorous algorithmic results in the literature. The authors also present results provided by the combinatorial chemistry software package OCOTILLO for combinatorial peptide design using real data libraries. The package provides exact solutions for general inverse problems based on shortest-path topological indices. The results are superior both in accuracy and computing time to the best software reports published in the literature. For 5-peptoid design, the computation is rigorously reduced to an exhaustive search of about 2% of the search space; the exact solutions are found in a few minutes.

  1. avoiding general chemistry textbooks' misrepresentations of ...

    African Journals Online (AJOL)

    IICBA01

    the proper definition of each of the terms analyzed, one problem is presented in order to ... It is often usual to refer to activities after defining Kp/Kc, stating that the .... This finding was also reported concerning some current Grade-12 chemistry ...

  2. Green polymer chemistry: biocatalysis and biomaterials

    Science.gov (United States)

    This overview briefly surveys the practice of green chemistry in polymer science. Eight related themes can be discerned from the current research activities: 1) biocatalysis, 2) bio-based building blocks and agricultural products, 3) degradable polymers, 4) recycling of polymer products and catalys...

  3. Benzoxazoles and oxazolopyridines in medicinal chemistry studies

    DEFF Research Database (Denmark)

    Demmer, Charles S; Bunch, Lennart

    2015-01-01

    and the use of benzoxazole as a bioisostere are discussed. The review is extended to cover structure-activity relationship studies of 2-substituted benzoxazoles, 2-substituted oxazolopyridines, and in perspective, application of the recently published novel heterocycle oxazolopyrazine in medicinal chemistry...

  4. The chemistry of D3-trishomocubane

    Science.gov (United States)

    Levandovsky, I. A.; Sharapa, D. I.; Cherenkova, O. A.; Gaidai, A. V.; Shubina, T. E.

    2010-12-01

    Data on the chemistry of D3-trishomocubane and its derivatives are described systematically. Different versions of construction of D3-trishomocubane cage are presented. The methods of synthesis of mono-, di- and poly-substituted D3-trishomocubanes and their heteroanalogues as well as their properties are considered. Data on biological activity of homocubanes are generalized.

  5. Progress in Kdo-glycoside chemistry

    Science.gov (United States)

    Kosma, Paul

    2016-01-01

    Glycosylation chemistry of 3-deoxy-D-manno-oct-2-ulosonic acid units has been considerably developed within the last decade. This review covers major achievements with respect to improved yields and anomeric selectivity as well as suppression of the elimination side reaction via selection of dedicated protecting groups and appropriate activation of the anomeric center. PMID:27274586

  6. Colloid and interface chemistry for nanotechnology

    CERN Document Server

    Kralchevsky, Peter

    2013-01-01

    Colloid and interface science dealt with nanoscale objects for nearly a century before the term nanotechnology was coined. An interdisciplinary field, it bridges the macroscopic world and the small world of atoms and molecules. Colloid and Interface Chemistry for Nanotechnology is a collection of manuscripts reflecting the activities of research teams that have been involved in the networking project Colloid and Interface Chemistry for Nanotechnology (2006-2011), Action D43, the European Science Foundation. The project was a part of the intergovernmental framework for Cooperation in Science an

  7. Switching surface chemistry with supramolecular machines.

    Energy Technology Data Exchange (ETDEWEB)

    Dunbar, Timothy D.; Kelly, Michael James; Jeppesen, Jan O. (University of California, Los Angeles, CA); Bunker, Bruce Conrad; Matzke, Carolyn M.; Stoddart, J. Fraser; Huber, Dale L.; Kushmerick, James G.; Flood, Amar H. (University of California, Los Angeles, CA); Perkins, Julie (University of California, Los Angeles, CA); Cao, Jianguo (University of California, Los Angeles, CA)

    2005-07-01

    Tethered supramolecular machines represent a new class of active self-assembled monolayers in which molecular configurations can be reversibly programmed using electrochemical stimuli. We are using these machines to address the chemistry of substrate surfaces for integrated microfluidic systems. Interactions between the tethered tetracationic cyclophane host cyclobis(paraquat-p-phenylene) and dissolved {pi}-electron-rich guest molecules, such as tetrathiafulvalene, have been reversibly switched by oxidative electrochemistry. The results demonstrate that surface-bound supramolecular machines can be programmed to adsorb or release appropriately designed solution species for manipulating surface chemistry.

  8. Striving toward a More "Precise" Chemistry

    Institute of Scientific and Technical Information of China (English)

    YAO Jiannian

    2011-01-01

    @@ On multiple temporal and spatial scales, chemistry explores the composition, structure and form of matter, its physical properties and biological activity as well as the chemical changes and synthesis reactions, striving to describe the colorful world of matter and reveal the molecular secrets of matter transformations and life processes using its theories and its unique language.As a fundamental and creative discipline of science, chemistry not only helps us to understand the nature of substances and make high-performing materials to serve economic development, but is distinctively characterized by the ability to invent novel and marvelous matters.

  9. Liquefaction chemistry and kinetics: Hydrogen utilization studies

    Energy Technology Data Exchange (ETDEWEB)

    Rothenberger, K.S.; Warzinski, R.P.; Cugini, A.V. [Pittsburgh Energy Technology Center, PA (United States)] [and others

    1995-12-31

    The objectives of this project are to investigate the chemistry and kinetics that occur in the initial stages of coal liquefaction and to determine the effects of hydrogen pressure, catalyst activity, and solvent type on the quantity and quality of the products produced. The project comprises three tasks: (1) preconversion chemistry and kinetics, (2) hydrogen utilization studies, and (3) assessment of kinetic models for liquefaction. The hydrogen utilization studies work will be the main topic of this report. However, the other tasks are briefly described.

  10. Industrial Chemistry Option in MSc Studies in Chemistry.

    Science.gov (United States)

    Shani, Arnon

    1982-01-01

    Discusses the rationale for and development of an industrial chemistry program in chemistry at Ben-Gurion University of the Negev in Israel. Includes an outline of the recommended 2-year curriculum and list of courses in this industrial chemistry option leading to a master of science degree. (Author/JN)

  11. Real World of Industrial Chemistry: Industrial Chemistry Bibliography.

    Science.gov (United States)

    Marmor, Solomon

    1985-01-01

    Presented is a bibliography of articles published in the "Journal of Chemical Education" (1968-1983) which focused on industrial chemistry. Items are listed under these headings: real world of industrial chemistry; industrial notes; subject matter articles; industrial chemistry experiments/demonstrations; academic-industrial interface;…

  12. Turkish Prospective Chemistry Teachers' Beliefs about Chemistry Teaching

    Science.gov (United States)

    Boz, Yezdan; Uzuntiryaki, Esen

    2006-01-01

    In order to study the beliefs of Turkish prospective chemistry teachers about teaching chemistry, semi-structured interviews were conducted with 12 prospective teachers. Analysis of the interviews revealed that most of the prospective teachers held intermediate (transition between constructivist and traditional) beliefs about chemistry teaching.…

  13. Is Chemistry Attractive for Pupils? Czech Pupils' Perception of Chemistry

    Science.gov (United States)

    Kubiatko, Milan

    2015-01-01

    Chemistry is an important subject due to understanding the composition and structure of the things around us. The main aim of the study was to find out the perception of chemistry by lower secondary school pupils. The partial aims were to find out the influence of gender, year of study and favorite subject on the perception of chemistry. The…

  14. Top Down Chemistry Versus Bottom up Chemistry

    Science.gov (United States)

    Oka, Takeshi; Witt, Adolf N.

    2016-06-01

    The idea of interstellar top down chemistry (TDC), in which molecules are produced from decomposition of larger molecules and dust in contrast to ordinary bottom up chemistry (BUC) in which molecules are produced synthetically from smaller molecules and atoms in the ISM, has been proposed in the chemistry of PAH and carbon chain molecules both for diffusea,c and dense cloudsb,d. A simple and natural idea, it must have occurred to many people and has been in the air for sometime. The validity of this hypothesis is apparent for diffuse clouds in view of the observed low abundance of small molecules and its rapid decrease with molecular size on the one hand and the high column densities of large carbon molecules demonstrated by the many intense diffuse interstellar bands (DIBs) on the other. Recent identification of C60^+ as the carrier of 5 near infrared DIBs with a high column density of 2×1013 cm-2 by Maier and others confirms the TDC. This means that the large molecules and dust produced in the high density high temperature environment of circumstellar envelopes are sufficiently stable to survive decompositions due to stellar UV radiaiton, cosmic rays, C-shocks etc. for a long time (≥ 10^7 year) of their migration to diffuse clouds and seems to disagree with the consensus in the field of interstellar grains. The stability of molecules and aggregates in the diffuse interstellar medium will be discussed. Duley, W. W. 2006, Faraday Discuss. 133, 415 Zhen,J., Castellanos, P., Paardekooper, D. M., Linnartz, H., Tielens, A. G. G. M. 2014, ApJL, 797, L30 Huang, J., Oka, T. 2015, Mol. Phys. 113, 2159 Guzmán, V. V., Pety, J., Goicoechea, J. R., Gerin, M., Roueff, E., Gratier, P., Öberg, K. I. 2015, ApJL, 800, L33 L. Ziurys has sent us many papers beginning Ziurys, L. M. 2006, PNAS 103, 12274 indicating she had long been a proponent of the idea. Campbell, E. K., Holz, M., Maier, J. P., Gerlich, D., Walker, G. A. H., Bohlender, D, 2016, ApJ, in press Draine, B. T. 2003

  15. Polymer Chemistry in High School.

    Science.gov (United States)

    Stucki, Roger

    1984-01-01

    Discusses why polymer chemistry should be added to the general chemistry curriculum and what topics are appropriate (listing traditional with related polymer topics). Also discusses when and how these topics should be taught. (JN)

  16. Green chemistry of carbon nanomaterials.

    Science.gov (United States)

    Basiuk, Elena V; Basiuk, Vladimir A

    2014-01-01

    The global trend of looking for more ecologically friendly, "green" techniques manifested itself in the chemistry of carbon nanomaterials. The main principles of green chemistry emphasize how important it is to avoid the use, or at least to reduce the consumption, of organic solvents for a chemical process. And it is precisely this aspect that was systematically addressed and emphasized by our research group since the very beginning of our work on the chemistry of carbon nanomaterials in early 2000s. The present review focuses on the results obtained to date on solvent-free techniques for (mainly covalent) functionalization of fullerene C60, single-walled and multi-walled carbon nanotubes (SWNTs and MWNTs, respectively), as well as nanodiamonds (NDs). We designed a series of simple and fast functionalization protocols based on thermally activated reactions with chemical compounds stable and volatile at 150-200 degrees C under reduced pressure, when not only the reactions take place at a high rate, but also excess reagents are spontaneously removed from the functionalized material, thus making its purification unnecessary. The main two classes of reagents are organic amines and thiols, including bifunctional ones, which can be used in conjunction with different forms of nanocarbons. The resulting chemical processes comprise nucleophilic addition of amines and thiols to fullerene C60 and to defect sites of pristine MWNTs, as well as direct amidation of carboxylic groups of oxidized nanotubes (mainly SWNTs) and ND. In the case of bifunctional amines and thiols, reactions of the second functional group can give rise to cross-linking effects, or be employed for further derivatization steps.

  17. Deep learning for computational chemistry.

    Science.gov (United States)

    Goh, Garrett B; Hodas, Nathan O; Vishnu, Abhinav

    2017-06-15

    The rise and fall of artificial neural networks is well documented in the scientific literature of both computer science and computational chemistry. Yet almost two decades later, we are now seeing a resurgence of interest in deep learning, a machine learning algorithm based on multilayer neural networks. Within the last few years, we have seen the transformative impact of deep learning in many domains, particularly in speech recognition and computer vision, to the extent that the majority of expert practitioners in those field are now regularly eschewing prior established models in favor of deep learning models. In this review, we provide an introductory overview into the theory of deep neural networks and their unique properties that distinguish them from traditional machine learning algorithms used in cheminformatics. By providing an overview of the variety of emerging applications of deep neural networks, we highlight its ubiquity and broad applicability to a wide range of challenges in the field, including quantitative structure activity relationship, virtual screening, protein structure prediction, quantum chemistry, materials design, and property prediction. In reviewing the performance of deep neural networks, we observed a consistent outperformance against non-neural networks state-of-the-art models across disparate research topics, and deep neural network-based models often exceeded the "glass ceiling" expectations of their respective tasks. Coupled with the maturity of GPU-accelerated computing for training deep neural networks and the exponential growth of chemical data on which to train these networks on, we anticipate that deep learning algorithms will be a valuable tool for computational chemistry. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  18. The Medicinal Chemistry of Dengue Virus.

    Science.gov (United States)

    Behnam, Mira A M; Nitsche, Christoph; Boldescu, Veaceslav; Klein, Christian D

    2016-06-23

    The dengue virus and related flaviviruses are an increasing global health threat. In this perspective, we comment on and review medicinal chemistry efforts aimed at the prevention or treatment of dengue infections. We include target-based approaches aimed at viral or host factors and results from phenotypic screenings in cellular assay systems for viral replication. This perspective is limited to the discussion of results that provide explicit chemistry or structure-activity relationship (SAR), or appear to be of particular interest to the medicinal chemist for other reasons. The discovery and development efforts discussed here may at least partially be extrapolated toward other emerging flaviviral infections, such as West Nile virus. Therefore, this perspective, although not aimed at flaviviruses in general, should also be able to provide an overview of the medicinal chemistry of these closely related infectious agents.

  19. Chalcone: A Privileged Structure in Medicinal Chemistry.

    Science.gov (United States)

    Zhuang, Chunlin; Zhang, Wen; Sheng, Chunquan; Zhang, Wannian; Xing, Chengguo; Miao, Zhenyuan

    2017-06-28

    Privileged structures have been widely used as an effective template in medicinal chemistry for drug discovery. Chalcone is a common simple scaffold found in many naturally occurring compounds. Many chalcone derivatives have also been prepared due to their convenient synthesis. These natural products and synthetic compounds have shown numerous interesting biological activities with clinical potentials against various diseases. This review aims to highlight the recent evidence of chalcone as a privileged scaffold in medicinal chemistry. Multiple aspects of chalcone will be summarized herein, including the isolation of novel chalcone derivatives, the development of new synthetic methodologies, the evaluation of their biological properties, and the exploration of the mechanisms of action as well as target identification. This review is expected to be a comprehensive, authoritative, and critical review of the chalcone template to the chemistry community.

  20. Medicinal chemistry and the pharmacy curriculum.

    Science.gov (United States)

    Khan, M O Faruk; Deimling, Michael J; Philip, Ashok

    2011-10-10

    The origins and advancements of pharmacy, medicinal chemistry, and drug discovery are interwoven in nature. Medicinal chemistry provides pharmacy students with a thorough understanding of drug mechanisms of action, structure-activity relationships (SAR), acid-base and physicochemical properties, and absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiles. A comprehensive understanding of the chemical basis of drug action equips pharmacy students with the ability to answer rationally the "why" and "how" questions related to drug action and it sets the pharmacist apart as the chemical expert among health care professionals. By imparting an exclusive knowledge base, medicinal chemistry plays a vital role in providing critical thinking and evidence-based problem-solving skills to pharmacy students, enabling them to make optimal patient-specific therapeutic decisions. This review highlights the parallel nature of the history of pharmacy and medicinal chemistry, as well as the key elements of medicinal chemistry and drug discovery that make it an indispensable component of the pharmacy curriculum.

  1. Chemistry Is Fun.

    Science.gov (United States)

    Yaniv, D; And Others

    1982-01-01

    Encouraging scientific thinking through open-ended experiments, allowing students access to common chemical instrumentation, and introduction to laboratory techniques are goals of a high school science laboratory program. Course content (general, inorganic, and organic chemistry), limitations, and course evaluation are discussed. (Author/JN)

  2. Microscale Gas Chemistry

    Science.gov (United States)

    Mattson, Bruce; Anderson, Michael P.

    2011-01-01

    The development of syringes having free movement while remaining gas-tight enabled methods in chemistry to be changed. Successfully containing and measuring volumes of gas without the need to trap them using liquids made it possible to work with smaller quantities. The invention of the LuerLok syringe cap also allowed the gas to be stored for a…

  3. Chemistry and Heritage

    Science.gov (United States)

    Vittoria Barbarulo, Maria

    2014-05-01

    Chemistry is the central science, as it touches every aspect of the society we live in and it is intertwined with many aspects of our culture; in particular, the strong link between Chemistry and Archaeology and Art History is being explored, offering a penetrating insight into an area of growing interest from an educational point of view. A series of vital and vibrant examples (i.e., ancient bronzes composition, colour changes due to natural pigment decomposition, marble degradation) has been proposed, on one hand, to improve student understanding of the relationship between cultural and scientific issues arising from the examination, the conservation, and the maintenance of cultural Heritage, on the other, to illustrate the role of the underlying Chemistry. In some case studies, a survey of the most relevant atmospheric factors, which are involved in the deterioration mechanisms, has also been presented to the students. First-hand laboratory experiences have been providing an invaluable means of discovering the full and varied world of Chemistry. Furthermore, the promotion of an interdisciplinary investigation of a famous painting or fresco, involving the study of its nature and significance, the definition of its historical context, any related literature, the chemical knowledge of the materials used, may be an excellent occasion to experiment the Content and Language Integrated Learning (CLIL). The aim of this approach is to convey the important message that everyone has the responsibility to care for and preserve Heritage for the benefit of present and future generations.

  4. The Chemistry of Griseofulvin

    DEFF Research Database (Denmark)

    Petersen, Asger Bjørn; Rønnest, Mads Holger; Larsen, Thomas Ostenfeld;

    2014-01-01

    Specific synthetic routes are presented in schemes to illustrate the chemistry, and the analogs are presented in a table format to give an accessible overview of the structures. Several patents have been published regarding the properties of griseofulvin and its derivatives including synthesis...

  5. Industrial chemistry; Chimie industrielle

    Energy Technology Data Exchange (ETDEWEB)

    Perrin, R. [Universite Claude Bernard, UFR, 69 - Lyon (France); Scharff, J.P. [Universite Claude Bernard, 69 - Lyon (France)]|[Ecole Superieure de Chimie, Physique et Electronique CPE, 69 - Lyon (France)

    1997-12-31

    This book takes stock of the main aspects of the industrial chemistry. It presents all the current chemical aspects concerning the preparation of the main inorganic, metallurgical, organic products and polymers. Are included all the problems related to raw materials, energy, reactions optimization, chemical risk, environment and cleansing, patent rights. It is devoted to students, technical men and engineers. (O.M.) 239 refs.

  6. Nobel Prize in Chemistry

    Science.gov (United States)

    2000-01-01

    The Royal Swedish Academy has awarded the 1999 Nobel Prize in Chemistry to Ahmed H. Zewail (California Institute of Technology, Pasadena, CA) "for his studies of the transition states of chemical reactions using femtosecond spectroscopy". Zewail's work has taken the study of the rates and mechanisms of chemical reactions to the ultimate degree of detail - the time scale of bond making and bond breaking.

  7. Analytical Chemistry Laboratory

    Science.gov (United States)

    Anderson, Mark

    2013-01-01

    The Analytical Chemistry and Material Development Group maintains a capability in chemical analysis, materials R&D failure analysis and contamination control. The uniquely qualified staff and facility support the needs of flight projects, science instrument development and various technical tasks, as well as Cal Tech.

  8. Supramolecular analytical chemistry.

    Science.gov (United States)

    Anslyn, Eric V

    2007-02-02

    A large fraction of the field of supramolecular chemistry has focused in previous decades upon the study and use of synthetic receptors as a means of mimicking natural receptors. Recently, the demand for synthetic receptors is rapidly increasing within the analytical sciences. These classes of receptors are finding uses in simple indicator chemistry, cellular imaging, and enantiomeric excess analysis, while also being involved in various truly practical assays of bodily fluids. Moreover, one of the most promising areas for the use of synthetic receptors is in the arena of differential sensing. Although many synthetic receptors have been shown to yield exquisite selectivities, in general, this class of receptor suffers from cross-reactivities. Yet, cross-reactivity is an attribute that is crucial to the success of differential sensing schemes. Therefore, both selective and nonselective synthetic receptors are finding uses in analytical applications. Hence, a field of chemistry that herein is entitled "Supramolecular Analytical Chemistry" is emerging, and is predicted to undergo increasingly rapid growth in the near future.

  9. Water Chemistry Laboratory Manual.

    Science.gov (United States)

    Jenkins, David; And Others

    This manual of laboratory experiments in water chemistry serves a dual function of illustrating fundamental chemical principles of dilute aqueous systems and of providing the student with some familiarity with the chemical measurements commonly used in water and wastewater analysis. Experiments are grouped in categories on the basis of similar…

  10. Supramolecular Chemistry in Water

    NARCIS (Netherlands)

    Oshovsky, Gennady V.; Reinhoudt, David N.; Verboom, Willem

    2007-01-01

    Supramolecular chemistry in water is a constantly growing research area because noncovalent interactions in aqueous media are important for obtaining a better understanding and control of the major processes in nature. This Review offers an overview of recent advances in the area of water-soluble sy

  11. Chemistry and Popperism.

    Science.gov (United States)

    Akeroyd, F. Michael

    1984-01-01

    Discusses the relationship of Karl Popper's theories to chemistry, examining scientific statements and verisimilitude (which indicates that newer theories should have a higher degree of truth content compared with older theories). Also provides examples illustrating the use of Agassi's criteria for assessing currently fashionable theories. (JN)

  12. Green chemistry metrics

    Science.gov (United States)

    Synthetic chemists have always had an objective to achieve reliable and high-yielding routes to the syntheses of targeted molecules. The importance of minimal waste generation has emphasized the use of green chemistry principles and sustainable development. These directions lead ...

  13. Chemistry Education and Mythology

    Directory of Open Access Journals (Sweden)

    Sule Aycan

    2005-01-01

    Full Text Available This study aimed to investigate the effect of mythological story in teaching chemistry. To this end the students in the class were divided into two homogenous groups. While the first group was thought in a traditional way, using a mythological story thought the second group. The story used was based on a Mountain just opposite the faculty.

  14. Forensic Chemistry Training

    Directory of Open Access Journals (Sweden)

    Zuhal GERÇEK

    2012-01-01

    Full Text Available Increasing the types of terrorism and crime nowadays, the importance of the forensic sciences can be bett er understood. Forensic science is the application of the wide spectrum of science to answer the question of legal system. It contains the application of the principles, techniques and methods of basic sciences and its main aim is the determination of the physical facts which are important in legal situations. Forensic chemistry is the branch of chemistry which performs the chemical analysis of evidences that used in the courts. Forensic chemist is the professional chemist who analyzes the evidences from crime scene and reaches a result by application of tests. Th us, they have to have a special education. In forensic laboratories candidates who have chemistry/biochemistry undergraduate degree and took biology and forensic chemistry lectures are preferred. It is necessary to design graduate and undergraduate education to train a forensic chemist. Science education should be at the core of the undergraduate education. In addition to this strong laboratory education on both science and forensic science should be given. Th e graduate program of forensic science example should contain forensic science subjects, strong academic lectures on special subjects and research and laboratory components.

  15. Online Organic Chemistry

    Science.gov (United States)

    Janowicz, Philip A.

    2010-01-01

    This is a comprehensive study of the many facets of an entirely online organic chemistry course. Online homework with structure-drawing capabilities was found to be more effective than written homework. Online lecture was found to be just as effective as in-person lecture, and students prefer an online lecture format with shorter Webcasts. Online…

  16. The Chemistry of Griseofulvin

    DEFF Research Database (Denmark)

    Petersen, Asger Bjørn; Rønnest, Mads Holger; Larsen, Thomas Ostenfeld

    2014-01-01

    Specific synthetic routes are presented in schemes to illustrate the chemistry, and the analogs are presented in a table format to give an accessible overview of the structures. Several patents have been published regarding the properties of griseofulvin and its derivatives including synthesis...

  17. Symmetry in chemistry

    CERN Document Server

    Jaffé, Hans H

    1977-01-01

    This book, devoted exclusively to symmetry in chemistry and developed in an essentially nonmathematical way, is a must for students and researchers. Topics include symmetry elements and operations, multiple symmetry operations, multiplication tables and point groups, group theory applications, and crystal symmetry. Extensive appendices provide useful tables.

  18. Evaluating Environmental Chemistry Textbooks.

    Science.gov (United States)

    Hites, Ronald A.

    2001-01-01

    A director of the Indiana University Center for Environmental Science Research reviews textbooks on environmental chemistry. Highlights clear writing, intellectual depth, presence of problem sets covering both the qualitative and quantitative aspects of the material, and full coverage of the topics of concern. Discusses the director's own approach…

  19. Analytical Chemistry Laboratory

    Science.gov (United States)

    Anderson, Mark

    2013-01-01

    The Analytical Chemistry and Material Development Group maintains a capability in chemical analysis, materials R&D failure analysis and contamination control. The uniquely qualified staff and facility support the needs of flight projects, science instrument development and various technical tasks, as well as Cal Tech.

  20. Array processors in chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ostlund, N.S.

    1980-01-01

    The field of attached scientific processors (''array processors'') is surveyed, and an attempt is made to indicate their present and possible future use in computational chemistry. The current commercial products from Floating Point Systems, Inc., Datawest Corporation, and CSP, Inc. are discussed.

  1. Online organic chemistry

    Science.gov (United States)

    Janowicz, Philip A.

    This is a comprehensive study of the many facets of an entirely online organic chemistry course. Online homework with structure-drawing capabilities was found to be more effective than written homework. Online lecture was found to be just as effective as in-person lecture, and students prefer an online lecture format with shorter Webcasts. Online office hours were found to be effective, and discussion sessions can be placed online as well. A model was created that explains 36.1% of student performance based on GPA, ACT Math score, grade in previous chemistry course, and attendance at various forms of discussion. Online exams have been created which test problem-solving skills and is instantly gradable. In these exams, students can submit answers until time runs out for different numbers of points. These facets were combined effectively to create an entirely online organic chemistry course which students prefer over the in-person alternative. Lastly, there is a vision for where online organic chemistry is going and what can be done to improve education for all.

  2. Evaluating Environmental Chemistry Textbooks.

    Science.gov (United States)

    Hites, Ronald A.

    2001-01-01

    A director of the Indiana University Center for Environmental Science Research reviews textbooks on environmental chemistry. Highlights clear writing, intellectual depth, presence of problem sets covering both the qualitative and quantitative aspects of the material, and full coverage of the topics of concern. Discusses the director's own approach…

  3. Chemistry in Protoplanetary Disks

    CERN Document Server

    Henning, Thomas

    2013-01-01

    This comprehensive review summarizes our current understanding of the evolution of gas, solids and molecular ices in protoplanetary disks. Key findings related to disk physics and chemistry, both observationally and theoretically, are highlighted. We discuss which molecular probes are used to derive gas temperature, density, ionization state, kinematics, deuterium fractionation, and study organic matter in protoplanetary disks.

  4. systemic chemistry triangle

    African Journals Online (AJOL)

    Temechegn

    This paper describes uses of the systemic chemistry triangle [SCT] in which we get the benefits of both ..... The teachers follows up the following scenario for teaching [Fig.12]:. 1. ... [SATL]: A 10- year's review, AJCE, 1(1) 29-47. 3. Fahmy ...

  5. Peat, industrial chemistry and technology

    Energy Technology Data Exchange (ETDEWEB)

    Fuchsman, C.H.

    1980-01-01

    This book is an attempt to enable chemists, engineers, and managers in North America and Western Europe to assess the industrial potential of peat. The chemical characteristics of peat, peat bitumens and peat carbohydrates are described. The technical matter concerns (1) solvent extraction processes, leading to the production of waxes and of by-products of potential interest in pharmaceutical chemistry; (2) acid hydrolysis, leading to the production of sugars supporting yeast products for high-protein livestock feed, and alcohol production, (3) pyrolysis, leading to the production of speciality high-production metallurgical coke, and activated carbon; and (4) the alkaline extraction of humic acids, leading to a variety of surface active agents, viscosity modifiers, and possible ingredients for the plastics and adhesive industries. The more important environmental aspects for man and nature are pointed out. (463 refs.)

  6. School Chemistry: An Historical and Philosophical Approach

    Science.gov (United States)

    Izquierdo-Aymerich, Mercè

    2013-07-01

    Since at least the eighteenth century scientific knowledge (then natural philosophy) was produced in groups of experts and specialists and was transmitted in schools, where, future experts and specialists were trained. The design of teaching has always been a complex process particularly in recent years when educational aims (for example, teaching scientific competence to everyone, not just to experts and specialists) present significant challenges. These challenges are much more than a simple reorganisation of the scientific knowledge pre-determined by the existing teaching tradition for different educational level. In the context of chemical education, the new teaching approaches should bring about not only the transmission of chemical knowledge but also a genuine chemical activity so as to ensure that students can acquire chemical thinking. Chemistry teaching should be revised according to contemporary demands of schooling. In order to move forward towards new teaching proposals, we must identify the genuine questions that generate `chemical criteria' and we should focus on them for teaching. We think that a good strategy is to look for those criteria in the philosophy and history of chemistry, from the perspective of didactics of science. This paper will examine the following questions: (1) How can school science be designed as a world-modelling activity by drawing on the philosophy of science. (2) How can `stories' about the emergence of chemical entities be identified by looking at the history of chemistry? (3) How can modelling strategies be structured in school chemistry activities?

  7. Aqueous Solution Chemistry of Plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Clark, David L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-01-28

    Things I have learned working with plutonium: Chemistry of plutonium is complex; Redox equilibria make Pu solution chemistry particularly challenging in the absence of complexing ligands; Understanding this behavior is key to successful Pu chemistry experiments; There is no suitable chemical analog for plutonium.

  8. Industrial Chemistry at Michigan Tech.

    Science.gov (United States)

    Bates, D. K.; Ponter, A. B.

    1985-01-01

    Discusses factors leading to the development of a four-year industrial chemistry program at Michigan Technological University and provides details of its structure. Includes brief descriptions of courses required in industrial chemistry but not in the traditional chemistry program and list of optional courses. (JN)

  9. Research Experience for Teachers at NRAO-Green Bank: Planning for Cometary Observations with the Green Bank Telescope and Its Application to Chemistry Classroom Activities

    Science.gov (United States)

    Hynes, Christopher; Lockman, F. J.; Lovell, A.

    2010-01-01

    The NSF-funded "Research Experience for Teachers" project provides teachers an opportunity to work on a current scientific or engineering research project. This paper will describe the development of a Python program as a further expansion of a previous mathematical model3 designed to simulate cometary data collected by the Green Bank Telescope (GBT). The program allows for user interaction to change parameters such as the comet's distance from the sun, the rate of production of gaseous outflows, lifetime of these gaseous particles and maximum limit for how many gas particles are generated. Furthermore this paper will present results of how students can write their own Python programming code to manipulate these parameters to generate velocity profiles of the out gassed chemical species. Students should be enlightened that Science can be cross disciplinary. Several concepts in Chemistry: sublimation, electromagnetic spectrum, quantum mechanics, gas behavior and chemical kinetics play an important role in the formation of a comet cloud and how that cloud could be observed using radio astronomy. Chemical species such as HCN, CS and HCO+1 have been observed in cometary clouds. The chemical composition of the cloud and its size are a function of its distance from the sun and the radial location from the center of the comet cloud. High-school students at the Louisiana School for Math, Science and the Arts, LA will learn Python programming language to create a mathematical model of a cometary cloud. The students will have formulated models for rate of sublimation, rate of photo-dissociation, and velocity of gas particles as the fundamental framework to determine frequencies and intensities of the molecular spectra. The students will be able to manipulate their code to create various comet cloud scenarios as it might be observed by the GBT.

  10. Examination on Expert Chemistry Teachers’ Secondary School Chemistry Textbook Usage

    Directory of Open Access Journals (Sweden)

    Canan NAKİBOĞLU

    2009-04-01

    Full Text Available The purpose of the study is to determine how chemistry textbooks used by expert chemistry teachers are used during teaching process in secondary education, and to find how prospective chemistry teachers evaluate the situation mentioned. Thus, a project concerned with how expert chemistry teachers use them in their classes was carried out. Based on the research context, an interview that was used to interview with expert chemistry teachers by prospective chemistry teachers was prepared by the author. Next, prospective chemistry teachers were asked to evaluate how expert chemistry teachers used textbooks. The sample group of the study consisted of 21 expert high school chemistry teachers working at schools in Balıkesir and 21 prospective chemistry teachers studying at Education Faculty of Balıkesir University during 2007-2008 academic years. The findings of the study revealed that expert chemistry teachers did not use textbooks during their teaching process while they used them as the sources of problems and exercises at the end of units. Furthermore, it was found that University Entrance Exam (OSS had an effect on how to use the textbooks by teachers.

  11. Copper Nanoparticles in Click Chemistry.

    Science.gov (United States)

    Alonso, Francisco; Moglie, Yanina; Radivoy, Gabriel

    2015-09-15

    The challenges of the 21st century demand scientific and technological achievements that must be developed under sustainable and environmentally benign practices. In this vein, click chemistry and green chemistry walk hand in hand on a pathway of rigorous principles that help to safeguard the health of our planet against negligent and uncontrolled production. Copper-catalyzed azide-alkyne cycloaddition (CuAAC), the paradigm of a click reaction, is one of the most reliable and widespread synthetic transformations in organic chemistry, with multidisciplinary applications. Nanocatalysis is a green chemistry tool that can increase the inherent effectiveness of CuAAC because of the enhanced catalytic activity of nanostructured metals and their plausible reutilization capability as heterogeneous catalysts. This Account describes our contribution to click chemistry using unsupported and supported copper nanoparticles (CuNPs) as catalysts prepared by chemical reduction. Cu(0)NPs (3.0 ± 1.5 nm) in tetrahydrofuran were found to catalyze the reaction of terminal alkynes and organic azides in the presence of triethylamine at rates comparable to those achieved under microwave heating (10-30 min in most cases). Unfortunately, the CuNPs underwent dissolution under the reaction conditions and consequently could not be recovered. Compelling experimental evidence on the in situ generation of highly reactive copper(I) chloride and the participation of copper(I) acetylides was provided. The supported CuNPs were found to be more robust and efficient catalyst than the unsupported counterpart in the following terms: (a) the multicomponent variant of CuAAC could be applied; (b) the metal loading could be substantially decreased; (c) reactions could be conducted in neat water; and (d) the catalyst could be recovered easily and reutilized. In particular, the catalyst composed of oxidized CuNPs (Cu2O/CuO, 6.0 ± 2.0 nm) supported on carbon (CuNPs/C) was shown to be highly versatile and very

  12. Connecting Acids and Bases with Encapsulation... and Chemistry with Nanotechnology

    Science.gov (United States)

    Criswell, Brett

    2007-01-01

    The features and the development of various new acids and bases activity sets that combines chemistry with nanotechnology are being described. These sets lead to the generation of many nanotechnology-based pharmaceuticals for the treatment of various diseases.

  13. Presidential Green Chemistry Challenge: 2002 Greener Synthetic Pathways Award

    Science.gov (United States)

    Presidential Green Chemistry Challenge 2002 award winner, Pfizer, improved its synthesis of sertraline, the active ingredient in its drug, Zoloft, to double the yield and reduce the use of raw materials, energy, and water.

  14. Presidential Green Chemistry Challenge: 2004 Greener Synthetic Pathways Award

    Science.gov (United States)

    Presidential Green Chemistry Challenge 2004 award winner, Bristol-Myers Squibb, manufactures paclitaxel, the active ingredient in the anticancer drug, Taxol, using plant cell fermentation and extraction to replace synthesis.

  15. Presidential Green Chemistry Challenge: 2012 Academic Award (Waymouth and Hedrick)

    Science.gov (United States)

    Presidential Green Chemistry Challenge 2012 award winners, Professor Robert M. Waymouth and Dr. James L. Hedrick, developed a broad class of highly active, environmentally benign, metal-free catalysts for synthesizing plastics.

  16. Presidential Green Chemistry Challenge: 2006 Greener Reaction Conditions Award

    Science.gov (United States)

    Presidential Green Chemistry Challenge 2006 award winner, Codexis, directed the evolution of three designer enzymes to produce the key chiral building block for atorvastatin, the active ingredient in the drug Lipitor.

  17. Contrail: A Module from Physical Chemistry On-Line Project

    Science.gov (United States)

    Chen, Franklin; Zielinski, Theresa Julia; Long, George

    2007-01-01

    The impact of contrails on Earth's climate is researched to understand the active area. It is suggested that the process of contrail formation involves combustion, cooling and ice formation, which are good comprehensive learning exercise for physical chemistry students.

  18. Connecting Acids and Bases with Encapsulation... and Chemistry with Nanotechnology

    Science.gov (United States)

    Criswell, Brett

    2007-01-01

    The features and the development of various new acids and bases activity sets that combines chemistry with nanotechnology are being described. These sets lead to the generation of many nanotechnology-based pharmaceuticals for the treatment of various diseases.

  19. Towards "Bildung"-Oriented Chemistry Education

    Science.gov (United States)

    Sjöström, Jesper

    2013-01-01

    This paper concerns "Bildung"-oriented chemistry education, based on a reflective and critical discourse of chemistry. It is contrasted with the dominant type of chemistry education, based on the mainstream discourse of chemistry. "Bildung"-oriented chemistry education includes not only content knowledge in chemistry, but also…

  20. General chemistry courses that can affect achievement: An action research study in developing a plan to improve undergraduate chemistry courses

    Science.gov (United States)

    Shweikeh, Eman

    Over the past 50 years, considerable research has been dedicated to chemistry education. In evaluating principal chemistry courses in higher education, educators have noted the learning process for first-year general chemistry courses may be challenging. The current study investigated perceptions of faculty, students and administrators on chemistry education at three institutions in Southern California. Via action research, the study sought to develop a plan to improve student engagement in general chemistry courses. A mixed method was utilized to analyze different perceptions on key factors determining the level of commitment and engagement in general chemistry education. The approach to chemistry learning from both a faculty and student perspective was examined including good practices, experiences and extent of active participation. The research study considered well-known measures of effective education with an emphasis on two key components: educational practices and student behavior. Institutional culture was inclusively assessed where cognitive expectations of chemistry teaching and learning were communicated. First, the extent in which faculty members are utilizing the "Seven Principles for Good Practice in Undergraduate Education" in their instruction was explored. Second, student attitudes and approaches toward chemistry learning were examined. The focus was on investigating student understanding of the learning process and the structure of chemistry knowledge. The seven categories used to measure students' expectations for learning chemistry were: effort, concepts, math link, reality link, outcome, laboratory, and visualization. This analysis represents the views of 16 faculty and 140 students. The results validated the assertion that students need some competencies and skills to tackle the challenges of the chemistry learning process to deeply engage in learning. A mismatch exists between the expectations of students and those of the faculty