- Aza-Michael Reaction for an Undergraduate Organic Chemistry Laboratory
- Nigam, Manisha, Rush, Brittney, Patel, Jay, Castillo, Raul, Dhar, Preeti | Journal of chemical education (v.93 / no.4 / pp.753-756 / 20160021-9584)
- A green, aza-Michael reaction is described that can be used to teach undergraduate students conjugate addition of nitrogen nucleophile to an alpha;, beta;-unsaturated es
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A green, aza-Michael reaction is described that can be used to teach undergraduate students conjugate addition of nitrogen nucleophile to an alpha;, beta;-unsaturated ester. Students analyze spectral data of the product obtained from the assigned reaction to determine product structure and propose the mechanism of its formation. The experiment requires simple glassware and can be performed during a 3 to 4 h laboratory period in the second semester of introductory organic chemistry after acyl substitution and conjugate addition have been covered in a lecture class. Graphic Abstract ACS Electronic Supporting Info
- Two chlorinated benzofuran derivatives from the marine fungus Pseudallescheria boydii.
- Yan, Dan-Feng, Lan, Wen-Jian, Wang, Kun-Teng, Huang, Lei, Jiang, Cai-Wu, Li, Hou-Jin | Natural product communications (v.10 / no.4 / pp.621-622 / 20151934-578x)
- The marine fungus Pseudallescheria boydii was isolated from the inner tissue of the starfish Acanthaster planci. This fungus was cultured in a high salinity glucose-pepto
초록보기원문보기 >
The marine fungus Pseudallescheria boydii was isolated from the inner tissue of the starfish Acanthaster planci. This fungus was cultured in a high salinity glucose-peptone-yeast extract (GPY) medium. Two new chlorinated benzofuran derivatives, 6-chloro-2-(2-hydroxypropan-2-yl)-2,3-dihydro-5 hydroxybenzofuran (1) and 7-chloro-2-(2-hydroxypropan-2-yl)-2,3-dihydro-5-hydroxybenzofuran (2), were obtained from the extract of the culture broth. Their structures were determined by analysis of the NMR and MS data.
- Single molecule TPM analysis of the catalytic pentad mutants of Cre and Flp site-specific recombinases: contributions of the pentad residues to the pre-chemical steps of recombination
- Fan, Hsiu-Fang, Cheng, Yong-Song, Ma, Chien-Hui, Jayaram, Makkuni | Nucleic acids research (v.43 / no.6 / pp.3237-3255 / 20150305-1048)
- Cre and Flp site-specific recombinase variants harboring point mutations at their conserved catalytic pentad positions were characterized using single molecule tethered p
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Cre and Flp site-specific recombinase variants harboring point mutations at their conserved catalytic pentad positions were characterized using single molecule tethered particle motion (TPM) analysis. The findings reveal contributions of these amino acids to the pre-chemical steps of recombination. They suggest functional differences between positionally conserved residues in how they influence recombinase-target site association and formation of #x2018;non-productive #x2019;, #x2018;pre-synaptic #x2019; and #x2018;synaptic #x2019; complexes. The most striking difference between the two systems is noted for the single conserved lysine. The pentad residues in Cre enhance commitment to recombination by kinetically favoring the formation of pre-synaptic complexes. These residues in Flp serve a similar function by promoting Flp binding to target sites, reducing non-productive binding and/or enhancing the rate of assembly of synaptic complexes. Kinetic comparisons between Cre and Flp, and between their derivatives lacking the tyrosine nucleophile, are consistent with a stronger commitment to recombination in the Flp system. The effect of target site orientation (head-to-head or head-to-tail) on the TPM behavior of synapsed DNA molecules supports the selection of anti-parallel target site alignment prior to the chemical steps. The integrity of the synapse, whose establishment/stability is fostered by strand cleavage in the case of Flp but not Cre, appears to be compromised by the pentad mutations.
- Animal and Education Contributed Papers
- | In vitro cellular developmental biology. Animal (v.52 / no.1 / pp.29-31 / 20161071-2690)
- Presents a biographical entry for each author and co-author included in this issue of the publication.
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- Cultural Value Shifting in Pronoun Use
- Yu, Feng, Peng, Theodore, Peng, Kaiping, Tang, Shi, Chen, Chuan Shi, Qian, Xiaojun, Sun, Pei, Han, Tingting, Chai, Fangyuan | Journal of cross-cultural psychology (v.47 / no.2 / pp.310-316 / 20160022-0221)
- By investigating the use of first-person pronouns in nine languages using the Google Ngram Database, we examined the degree to which different cultural values skewed towa
초록보기원문보기 >
By investigating the use of first-person pronouns in nine languages using the Google Ngram Database, we examined the degree to which different cultural values skewed toward individualism or collectivism over a span of 59 years. We found that in eight of nine languages (British English being the exception), first-person singular pronouns (vs. first-person plural pronouns) have become increasingly prevalent, which in turn points to a rising sense of individualism. British English showed a U-shaped curve trend in the use of first-person singular pronouns (vs. first-person plural pronouns). Although they initially decreased, British English #x2019;s first-person singular pronouns (vs. first-person plural pronouns) use was higher than most other languages throughout the whole period. Chinese displayed a fluctuating pattern wherein the use of first-person singular pronouns (vs. first-person plural pronouns) increased in recent periods. The dynamics of cultural change and culture diversity were discussed.
- Short-chain chlorinated paraffins in cooking oil and related products from China
- Cao, Y., Harada, K.H., Liu, W., Yan, J., Zhao, C., Niisoe, T., Adachi, A., Fujii, Y., Nouda, C., Takasuga, T., Koizumi, A. | Chemosphere (v.138 / pp.104-111 / 20150045-6535)
- Short-chain chlorinated paraffins (SCCPs) are emerging persistent organic pollutants. It has been found that dietary intakes of SCCPs in China have recently increased and
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Short-chain chlorinated paraffins (SCCPs) are emerging persistent organic pollutants. It has been found that dietary intakes of SCCPs in China have recently increased and are now higher than in Japan and Korea. The contribution of cooking oil to dietary exposure to SCCPs in China was evaluated by analyzing SCCPs in cooking oil, raw seeds used to produce cooking oil, and fried confectionery products collected in China in 2010 and 2012. Detectable amounts of SCCP homologs were found in 48 out of the 49 cooking oil samples analyzed, and the SCCP concentrations varied widely, from -1 . Estimated dietary intakes of total SCCPs in cooking oil ranged from -1 . The estimated dietary intake of SCCPs was relatively high (mean 14.8 mu;gd -1 ) for residents of Beijing. Fried confectionery was found to contain SCCP concentrations of 11-1000ngg -1 . Cooking oil might therefore be one of the sources of SCCPs to Chinese diets. SCCPs were also detected in raw seeds used to produce cooking oil, but the concentrations varied widely. The SCCP homolog patterns in the raw seed and cooking oil samples were different, implying that the seeds used to produce the oil (and therefore the soil on which the seeds were produced) were unlikely to be the sources of SCCPs in cooking oil. Further investigations are needed to determine the routes through which cooking oil becomes contaminated with SCCPs during the production and processing of the oil.
- Natural products for chronic cough : Text mining the East Asian historical literature for future therapeutics
- Shergis, Johannah Linda, Wu, Lei, May, Brian H, Zhang, Anthony Lin, Guo, Xinfeng, Lu, Chuanjian, Xue, Charlie Changli | Chronic respiratory disease (v.12 / no.3 / pp.204-211 / 20151479-9723)
- Chronic cough is a significant health burden. Patients experience variable benefits from over the counter and prescribed products, but there is an unmet need to provide m
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Chronic cough is a significant health burden. Patients experience variable benefits from over the counter and prescribed products, but there is an unmet need to provide more effective treatments. Natural products have been used to treat cough and some plant compounds such as pseudoephedrine from ephedra and codeine from opium poppy have been developed into drugs. Text mining historical literature may offer new insight for future therapeutic development. We identified natural products used in the East Asian historical literature to treat chronic cough. Evaluation of the historical literature revealed 331 natural products used to treat chronic cough. Products included plants, minerals and animal substances. These natural products were found in 75 different books published between AD 363 and 1911. Of the 331 products, the 10 most frequently and continually used products were examined, taking into consideration findings from contemporary experimental studies. The natural products identified are promising and offer new directions in therapeutic development for treating chronic cough.
- Cinematic chronotopes., Here, now, me
- Eugeni, Ruggero | New review of film and television studies (v.13 / no.3 / pp.292-296 / 20151740-0309)
- Although cinema is now commonly recognized as a significant source of knowledge about law, in this article I argue that it is also a space in which law is questioned, ret
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- Anti-infective Natural Products from Cyanobacteria
- Niedermeyer, Timo Horst Johannes | Planta medica (v.81 / no.15 / pp.1309-1325 / 20150032-0943)
- Cyanobacteria are a promising yet underexplored source for novel natural products with potent biological activities. While predominantly cytotoxic compounds have been iso
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Cyanobacteria are a promising yet underexplored source for novel natural products with potent biological activities. While predominantly cytotoxic compounds have been isolated from cyanobacteria in the past, there are also a significant number of compounds known that possess anti-infective activities. As the need for novel anti-infective lead compounds is high, this manuscript aims at giving a concise overview on the current knowledge about anti-infective secondary metabolites isolated from cyanobacteria. Antibacterial, antifungal, antiviral, antiprotozoal, and molluscicidal activities are discussed. Covering up to February 2015.
- Singapore, the state, and decolonial spatiality
- Goh, Daniel PS | Cultural dynamics (v.27 / no.2 / pp.215-226 / 20150921-3740)
- The proposition that Singapore is a successful Asian model of urban culture and political economy is a discomforting one. I had thought this was a postcolonial problem of
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The proposition that Singapore is a successful Asian model of urban culture and political economy is a discomforting one. I had thought this was a postcolonial problem of hybrid identity making and political practice. But in my attempts to study Singapore society, from street carnivals to popular religion, I have ended up facing the state #x2019;s knowing rationalizations in the discursive materials and material space itself . When I focus on the state and its archive, I end up looking at society and its culture transcribed, rationalized and spatialized . Our epistemic blind spot in Asian cultural studies is the coloniality of the state and its spatiality. Singapore is exceptional because the state took the urban logics of Asian developmentalism to its conclusion, flattening rich cultural lifeworlds to spaces of bare life so as to reconstruct society in the state #x2019;s own modern imaginary of the good life. The state continues to do this in spite of the deterritorialization of globalization. The Singapore model offers the promise of remaining colonial and territorializing. In response, we need new methods of decolonial spatiality involving the urban grassroots and the intellectual strike.
- Chloride penetration in concrete exposed to cyclic drying-wetting and carbonation
- Ye, H., Jin, X., Fu, C., Jin, N., Xu, Y., Huang, T. | Construction building materials (v.112 / pp.457-463 / 20160950-0618)
- In this paper, the chloride penetration process in concrete exposed to a cyclic drying-wetting and carbonation environment was experimentally characterized. In order to b
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In this paper, the chloride penetration process in concrete exposed to a cyclic drying-wetting and carbonation environment was experimentally characterized. In order to better represent the concrete in service, chloride penetration tests were performed on concrete with various levels of flexural loading and incorporation of supplemental cementitious materials (i.e. blast-furnace slag and low calcium fly ash). The result shows that the chloride penetration profile in concrete is a result of multiple interactive deteriorating mechanisms and dependent on the properties and stress status of concrete itself. Carbonation induces considerable chloride (both free and bound) redistribution in concrete, rendering chloride ions ingress from carbonated region towards un-carbonated region. The incorporation of supplemental cementitious materials makes concrete more vulnerable to carbonation-induced chloride movements due to its less amount of portlandite. The increased magnitude of flexural loading results in higher chloride content in concrete probably by forming some micro-cracks.
- Chloride Anions Regulate Kinetics but Not Voltage-Sensor Qmax of the Solute Carrier SLC26a5
- Santos-Sacchi, J., Song, L. | Biophysical journal (v.110 / no.11 / pp.2551-2561 / 20160006-3495)
- In general, SLC26 solute carriers serve to transport a variety of anions across biological membranes. However, prestin (SLC26a5) has evolved, now serving as a motor prote
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In general, SLC26 solute carriers serve to transport a variety of anions across biological membranes. However, prestin (SLC26a5) has evolved, now serving as a motor protein in outer hair cells (OHCs) of the mammalian inner ear and is required for cochlear amplification, a mechanical feedback mechanism to boost auditory performance. The mechanical activity of the OHC imparted by prestin is driven by voltage and controlled by anions, chiefly intracellular chloride. Current opinion is that chloride anions control the Boltzmann characteristics of the voltage sensor responsible for prestin activity, including Q max , the total sensor charge moved within the membrane, and V h , a measure of prestin's operating voltage range. Here, we show that standard narrow-band, high-frequency admittance measures of nonlinear capacitance (NLC), an alternate representation of the sensor's charge-voltage (Q-V) relationship, is inadequate for assessment of Q max , an estimate of the sum of unitary charges contributed by all voltage sensors within the membrane. Prestin's slow transition rates and chloride-binding kinetics adversely influence these estimates, contributing to the prevalent concept that intracellular chloride level controls the quantity of sensor charge moved. By monitoring charge movement across frequency, using measures of multifrequency admittance, expanded displacement current integration, and OHC electromotility, we find that chloride influences prestin kinetics, thereby controlling charge magnitude at any particular frequency of interrogation. Importantly, however, this chloride dependence vanishes as frequency decreases, with Q max asymptoting at a level irrespective of the chloride level. These data indicate that prestin activity is significantly low-pass in the frequency domain, with important implications for cochlear amplification. We also note that the occurrence of voltage-dependent charge movements in other SLC26 family members may be hidden by inadequate interrogation timescales, and that revelation of such activity could highlight an evolutionary means for kinetic modifications within the family to address hearing requirements in mammals.
- Three dimensional quantification of anisotropic void evolution in deformed semi-crystalline polyamide 6
- Laiarinandrasana, L., Klinkova, O., Nguyen, F., Proudhon, H., Morgeneyer, T.F., Ludwig, W. | International journal of plasticity (v.83 / pp.19-36 / 20160749-6419)
- The evolution of voids has been used as an efficient indicator of the volume changes occurring during deformation for polymers which undergo high levels of plasticity. Th
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The evolution of voids has been used as an efficient indicator of the volume changes occurring during deformation for polymers which undergo high levels of plasticity. This has to be taken into account in determining the constitutive models for these polymers. Void growth during uniaxial stretching of a semi-crystalline polyamide 6 has been studied using 3D image analysis of tomography data. Tests on axi-symmetrical notched round bars have been stopped at: (i) the maximum net stress; (ii) the end of the stress softening stage; (iii) the onset of the final failure. Local synchrotron tomography has been performed so as to observe voids in a predetermined volume of interest around the minimum net section. The shape of the voids was found to be cylindrical. Mathematical morphology analysis was used to identify 3D voids, allowing the void diameter and height histograms to be obtained. An anisotropic shape factor parameter was defined as the ratio between the void diameter and the void height. This shape factor was found to evolve with the degree of deformation. The principal strain components of the voids were calculated and plotted, showing anisotropy and a heterogeneous distribution. The irreversible void growth noted as plastic dilation was also found to be heterogeneous in the deformed net section.
- Design of the 15 GHz BPM test bench for the CLIC test facility to perform precise stretched-wire RF measurements
- Zorzetti, Silvia, Fanucci, Luca, Mu?oz, Natalia Galindo, Wendt, Manfred | Measurement science technology (v.26 / no.9 / pp.094005 / 20150957-0233)
- The Compact Linear Collider (CLIC) requires a low emittance beam transport and preservation, thus a precise control of the beam orbit along up to 50 km of the accelerator
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The Compact Linear Collider (CLIC) requires a low emittance beam transport and preservation, thus a precise control of the beam orbit along up to 50 km of the accelerator components in the sub- #956;m regime is required. Within the PACMAN 3 (Particle Accelerator Components Metrology and Alignment to the Nanometer Scale) PhD training action a study with the objective of pre-aligning the electrical centre of a 15 GHz cavity beam position monitor (BPM) to the magnetic centre of the main beam quadrupole is initiated. Of particular importance is the design of a specific test bench to study the stretched-wire setup for the CLIC Test Facility (CTF3) BPM, focusing on the aspects of microwave signal excitation, transmission and impedance-matching, as well as the mechanical setup and reproducibility of the measurement method.
- A new antibiotic kills pathogens without detectable resistance
- Ling, Losee L., Schneider, Tanja, Peoples, Aaron J., Spoering, Amy L., Engels, Ina, Conlon, Brian P., Mueller, Anna, Sch auml, berle, Till F., Hughes, Dallas E., Epstein, Slava, Jones, Michael, Lazarides, Linos, Steadman, Victoria A., Cohen, Douglas R., Felix, Cintia R., Fetterman, K. Ashley, Millett, William P., Nitti, Anthony G., Zullo, Ashley M., Chen, Chao, Lewis, Kim | Nature (v.517 / no.7535 / pp.455-459 / 20150028-0836)
- Antibiotic resistance is spreading faster than the introduction of new compounds into clinical practice, causing a public health crisis. Most antibiotics were produced by
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Antibiotic resistance is spreading faster than the introduction of new compounds into clinical practice, causing a public health crisis. Most antibiotics were produced by screening soil microorganisms, but this limited resource of cultivable bacteria was overmined by the 1960s. Synthetic approaches to produce antibiotics have been unable to replace this platform. Uncultured bacteria make up approximately 99% of all species in external environments, and are an untapped source of new antibiotics. We developed several methods to grow uncultured organisms by cultivation in situ or by using specific growth factors. Here we report a new antibiotic that we term teixobactin, discovered in a screen of uncultured bacteria. Teixobactin inhibits cell wall synthesis by binding to a highly conserved motif of lipid II (precursor of peptidoglycan) and lipid III (precursor of cell wall teichoic acid). We did not obtain any mutants of Staphylococcus aureus or Mycobacterium tuberculosis resistant to teixobactin. The properties of this compound suggest a path towards developing antibiotics that are likely to avoid development of resistance.
- The US crop insurance program and WTO disciplines
- Glauber, Joseph William | Agricultural finance review (v.76 / no.1 / pp.6-14 / 20160002-1466)
- Purpose ndash; The purpose of this paper is to examine the US crop insurance programs in the context of domestic support disciplines under the World Trade Organization
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Purpose ndash; The purpose of this paper is to examine the US crop insurance programs in the context of domestic support disciplines under the World Trade Organization (WTO). Crop insurance has become an integral part of many domestic support programs, not just in developed countries, but in important emerging markets as well. An often-cited impetus for the growth in insurance program is the potential treatment of such programs as exempt from WTO reduction commitments. Design/methodology/approach ndash; A detailed examination of the so-called ldquo;green box provisions rdquo; of the Uruguay Round Agreement on Agriculture is presented with particular emphasis on eligibility criteria for crop yield and revenue insurance programs. Findings ndash; While WTO rules potentially shield green box policies from reduction, few developed countries have notified agricultural insurance policies under Annex 2. Moreover, crop insurance programs have been challenged in recent WTO dispute settlement cases and domestic countervailing duty investigations. Originality/value ndash; The paper presents a unique perspective on a program which has become the largest single farm program in the USA.
- Engaging Organic Chemistry Students Using ChemDraw for iPad
- Morsch, Layne A., Lewis, Michael | Journal of chemical education (v.92 / no.8 / pp.1402-1405 / 20150021-9584)
- Drawing structures, mechanisms, and syntheses is a vital part of success in organic chemistry courses. ChemDraw for iPad has been used to increase classroom experiences i
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Drawing structures, mechanisms, and syntheses is a vital part of success in organic chemistry courses. ChemDraw for iPad has been used to increase classroom experiences in the preparation of high quality chemical drawings. The embedded Flick-to-Share allows for simple, real-time exchange of ChemDraw documents. ChemDraw for iPad also allows documents to be readily shared with students via e-mail directly from the program. ChemDraw for iPad increased engagement and enhanced interactions between students and instructors in organic chemistry classes. Graphic Abstract
- Allergic sensitization is age-dependently associated with rhinitis, but less so with asthma
- Warm, K., Hedman, L., Lindberg, A., Lotvall, J., Lundback, B., Ronmark, E. | The Journal of allergy and clinical immunology : official organ of American Academy of Allergy (v.136 / no.6 / pp.1559-1565.e2 / 20150091-6749)
- Background: Epidemiologic data describing the association between allergic sensitization and asthma and allergic rhinitis in adults are scarce. Objective: To determine th
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Background: Epidemiologic data describing the association between allergic sensitization and asthma and allergic rhinitis in adults are scarce. Objective: To determine the prevalence and impact of specific sensitization to airborne allergens on asthma and allergic rhinitis among adults in relation to age. Methods: A random population sample (age 21-86 years) was examined with structured interview and analysis of specific IgE to 9 common airborne allergens. Of those invited, 692 (68%) subjects participated in blood sampling. IgE level of 0.35 U/mL or more to the specific allergen was defined as a positive test result. Results: Allergic sensitization decreased with increasing age, both in the population sample and among subjects with asthma and allergic rhinitis. In a multivariate model, sensitization to animal was significantly positively associated with asthma (odds ratio [OR], 4.80; 95% CI, 2.68-8.60), whereas sensitization to both animal (OR, 3.90; 95% CI, 2.31-6.58) and pollen (OR, 4.25; 95% CI, 2.55-7.06) was significantly associated with allergic rhinitis. The association between allergic sensitization and rhinitis was consistently strongest among the youngest age group, whereas this pattern was not found for asthma. The prevalence of allergic sensitization among patients with asthma decreased by increasing age of asthma onset, 86% with asthma onset at age 6 y or less, 56% at age 7 to 19 years, and 26% with asthma onset at age 20 years or more. Conclusions: Sensitization to animal was associated with asthma across all age groups; allergic rhinitis was associated with sensitization to both pollen and animal and consistently stronger among younger than among older adults. Early onset of asthma was associated with allergic sensitization among adults with asthma.
- Promoting Representational Competence with Molecular Models in Organic Chemistry
- Stull, Andrew T., Gainer, Morgan, Padalkar, Shamin, Hegarty, Mary | Journal of chemical education (v.93 / no.6 / pp.994-1001 / 20160021-9584)
- Mastering the many different diagrammatic representations of molecules used in organic chemistry is challenging for students. This article summarizes recent research show
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Mastering the many different diagrammatic representations of molecules used in organic chemistry is challenging for students. This article summarizes recent research showing that manipulating 3-D molecular models can facilitate the understanding and use of these representations. Results indicate that students are more successful in translating between diagrams when they have models available, that using a model to enact the translation process in the world is predictive of learning, and that using models as feedback (to check the accuracy of diagram translation) is particularly effective. Model-based feedback is superior to verbal feedback alone, models scaffold learning rather than act as a crutch, learning with model-based instruction is resilient over a delay of several days, and learning with models transfers to performance when models are no longer available. Finally, virtual models are equivalent to hand-held models in promoting learning in the studied contexts. Graphic Abstract
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