scholarly journals Synthetic and semi-synthetic approaches to unprotected N-glycan oxazolines

2018 ◽  
Vol 14 ◽  
pp. 416-429 ◽  
Author(s):  
Antony J Fairbanks
Keyword(s):  
Total Synthesis ◽  
Important Application ◽  
Protecting Group ◽  
Natural Sources ◽  
Bean Flour ◽  
Egg Yolks ◽  
Synthetic Sequence ◽  
The Many ◽  
Synthetic Approaches ◽  
Selection Of

N-Glycan oxazolines have found widespread use as activated donor substrates for endo-β-N-acetylglucosaminidase (ENGase) enzymes, an important application that has correspondingly stimulated interest in their production, both by total synthesis and by semi-synthesis using oligosaccharides isolated from natural sources. Amongst the many synthetic approaches reported, the majority rely on the fabrication (either by total synthesis, or semi-synthesis from locust bean gum) of a key Manβ(1–4)GlcNAc disaccharide, which can then be elaborated at the 3- and 6-positions of the mannose unit using standard glycosylation chemistry. Early approaches subsequently relied on the Lewis acid catalysed conversion of peracetylated N-glycan oligosaccharides produced in this manner into their corresponding oxazolines, followed by global deprotection. However, a key breakthrough in the field has been the development by Shoda of 2-chloro-1,3-dimethylimidazolinium chloride (DMC), and related reagents, which can direct convert an oligosaccharide with a 2-acetamido sugar at the reducing terminus directly into the corresponding oxazoline in water. Therefore, oxazoline formation can now be achieved in water as the final step of any synthetic sequence, obviating the need for any further protecting group manipulations, and simplifying synthetic strategies. As an alternative to total synthesis, significant quantities of several structurally complicated N-glycans can be isolated from natural sources, such as egg yolks and soy bean flour. Enzymatic transformations of these materials, in concert with DMC-mediated oxazoline formation as a final step, allow access to a selection of N-glycan oxazoline structures both in larger quantities and in a more expedient fashion than is achievable by total synthesis.

Costumes and Choreography from Bodenwieser's Trunk: The Coat as Affective Memory

2019 ◽  
Vol 37 (1) ◽  
pp. 89-110
Author(s):  
Rachel Fensham
Keyword(s):  
Modern Dance ◽  
Human Condition ◽  
Personal Life ◽  
Creative Thought ◽  
Cain And Abel ◽  
Embodied Research ◽  
The Many ◽  
The One ◽  
Material Evidence ◽  
Selection Of

The Viennese modern choreographer Gertrud Bodenwieser's black coat leads to an analysis of her choreography in four main phases – the early European career; the rise of Nazism; war's brutality; and postwar attempts at reconciliation. Utilising archival and embodied research, the article focuses on a selection of Bodenwieser costumes that survived her journey from Vienna, or were remade in Australia, and their role in the dramaturgy of works such as Swinging Bells (1926), The Masks of Lucifer (1936, 1944), Cain and Abel (1940) and The One and the Many (1946). In addition to dance history, costume studies provides a distinctive way to engage with the question of what remains of performance, and what survives of the historical conditions and experience of modern dance-drama. Throughout, Hannah Arendt's book The Human Condition (1958) provides a critical guide to the acts of reconstruction undertaken by Bodenwieser as an émigré choreographer in the practice of her craft, and its ‘materializing reification’ of creative thought. As a study in affective memory, information regarding Bodenwieser's personal life becomes interwoven with the author's response to the material evidence of costumes, oral histories and documents located in various Australian archives. By resurrecting the ‘dead letters’ of this choreography, the article therefore considers how dance costumes offer the trace of an artistic resistance to totalitarianism.

Short Protecting Group-free Syntheses of CDE Synthon of Racemic Camptothecin

2020 ◽  
Vol 17 (7) ◽  
pp. 588-591
Author(s):  
Pingxuan Shao ◽  
Wei Lu ◽  
Lei Wang
Keyword(s):  
Total Synthesis ◽  
Future Development ◽  
Protecting Group ◽  
Short Route ◽  
The Future ◽  
Tricyclic Ketone

A practical and concise total synthesis of tricyclic ketone 7 (CDE ring), a valuable intermediate for the synthesis of racemic camptothecin and analogs, was described (8 chemical steps and 29% overall yield). The synthesis starts with two inexpensive, readily available materials and is operationally simple to perform. It is worth mentioning that the reported protecting group-free synthesis, with advantages of a short route, would be helpful for the future development of industry-scale syntheses of camptothecin-family alkaloids.

Precursors to Public Choice

2019 ◽  
pp. 796-816
Author(s):  
Iain McLean
Keyword(s):  
Public Choice ◽  
Social Choice ◽  
Choice Theory ◽  
Social Choice Theory ◽  
Ancient Greek ◽  
The Social ◽  
Mathematical Skill ◽  
The Many ◽  
Selection Of

This chapter reviews the many appearances, disappearances, and reappearances of axiomatic thought about social choice and elections since the era of ancient Greek democracy. Social choice is linked to the wider public-choice movement because both are theories of agency. Thus, just as the first public-choice theorists include Hobbes, Hume, and Madison, so the first social-choice theorists include Pliny, Llull, and Cusanus. The social-choice theory of agency appears in many strands. The most important of these are binary vs. nonbinary choice; aggregation of judgement vs. aggregation of opinion; and selection of one person vs. selection of many people. The development of social choice required both a public-choice mindset and mathematical skill.

Evidence-based Assessment

2010 ◽  
pp. 76-98
Author(s):  
John Hunsley ◽  
Eric J. Mash
Keyword(s):  
Decision Making ◽  
Clinical Assessment ◽  
Assessment Process ◽  
Evidence Based ◽  
The Past ◽  
Specific Assessment ◽  
The Many ◽  
Selection Of ◽  
Made In

Evidence-based assessment relies on research and theory to inform the selection of constructs to be assessed for a specific assessment purpose, the methods and measures to be used in the assessment, and the manner in which the assessment process unfolds. An evidence-based approach to clinical assessment necessitates the recognition that, even when evidence-based instruments are used, the assessment process is a decision-making task in which hypotheses must be iteratively formulated and tested. In this chapter, we review (a) the progress that has been made in developing an evidence-based approach to clinical assessment in the past decade and (b) the many challenges that lie ahead if clinical assessment is to be truly evidence-based.

scholarly journals The Recent Progress of Natural Sources and Manufacturing Process of Biodiesel: A Review

2021 ◽  
Vol 13 (10) ◽  
pp. 5599
Author(s):  
Eko Supriyanto ◽  
Jayan Sentanuhady ◽  
Ariyana Dwiputra ◽  
Ari Permana ◽  
Muhammad Akhsin Muflikhun
Keyword(s):  
Recent Progress ◽  
Review Paper ◽  
Ghg Emissions ◽  
Production Method ◽  
Biodiesel Production ◽  
Natural Sources ◽  
Harmful Emissions ◽  
Daily Energy ◽  
The Cost ◽  
Selection Of

Biodiesel has caught the attention of many researchers because it has great potential to be a sustainable fossil fuel substitute. Biodiesel has a non-toxic and renewable nature and has been proven to emit less environmentally harmful emissions such as hydrocarbons (HC), and carbon monoxide (CO) as smoke particles during combustion. Problems related to global warming caused by greenhouse gas (GHG) emissions could also be solved by utilizing biodiesel as a daily energy source. However, the expensive cost of biodiesel production, mainly because of the cost of natural feedstock, hinders the potential of biodiesel commercialization. The selection of natural sources of biodiesel should be made with observations from economic, agricultural, and technical perspectives to obtain one feasible biodiesel with superior characteristics. This review paper presents a detailed overview of various natural sources, their physicochemical properties, the performance, emission, and combustion characteristics of biodiesel when used in a diesel engine. The recent progress in studies about natural feedstocks and manufacturing methods used in biodiesel production were evaluated in detail. Finally, the findings of the present work reveal that transesterification is currently the most superior and commonly used biodiesel production method compared to other methods available.

Synthetic Approaches Towards the Total synthesis of tubulysin and its fragments: A review

2021 ◽  
Vol 19 ◽  
Author(s):  
Nosheen Iqbal ◽  
Ameer Fawad Zahoor ◽  
Nasir Rasool ◽  
Samreen Gul Khan ◽  
Rabia Akhtar ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Claisen Rearrangement ◽  
Antitumor Agents ◽  
Aldol Reaction ◽  
Multidrug Resistant ◽  
Novel Drugs ◽  
Mukaiyama Aldol ◽  
Ic50 Values ◽  
Barbier Reaction ◽  
Synthetic Approaches

Background: Tubulysins, linear tetrapeptides show extraordinary cytotoxicity against various cancer cells, with IC50 values in nano or picomolar range. Due to their extremely vigorous anti-proliferative and antiangiogenic characteristics, tubulysins exhibit captivating prospects in the development of anticancer drugs. This review focuses on diverse routes for the total synthesis of natural and synthetic tubulysins as well as their fragments. Objective: The purpose of this review is to present the synthetic strategies for the development of antitumor agents, tubulysins. Conclusion: A range of synthetic pathways adopted for the total synthesis of tubulysins and their fragments have been described in this review. Synthesis of fragments, Tuv, Tup, and Tut can be accomplished by adopting appropriate strategies such as Manganese-mediated synthesis, Ireland-Claisen rearrangement, Mukaiyama aldol reaction, and Mannich process etc. Tubulysin B, D, U, V, and N14-desacetoxytubulysin H have been prepared through Mitsunobu reaction, tert-butanesulfinamide method, Tandem reaction, aza-Barbier reaction, Evans aldol reaction, and C-H activation strategies etc. The remarkable anticancer potential of tubulysins toward a substantiate target make them prominent leads for developing novel drugs against multidrug-resistant cancers.

Le fonti, i metodi e le narrazioni della storia della videoarte in Italia negli anni Settanta

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Lisa Parola
Keyword(s):  
Comparative Study ◽  
Contemporary Art ◽  
Narrative Structure ◽  
Video Art ◽  
Wide Range ◽  
History Of ◽  
Selection For ◽  
The Many ◽  
Art And Architecture ◽  
Selection Of

This essay derives from the primary need to make order between direct and indirect sources available for the reconstruction of the history of video art in Italy in the seventies. In fact, during the researches for the Ph.D. thesis it became clear that in most cases it is difficult to define, in terms of facts, which of the different historiographies should be taken into consideration to deepen the study of video art in Italy. Beyond legitimate differences of perspectives and methods, historiographical narratives all share similar issues and narrative structure. The first intention of the essay is, therefore, to compare the different historiographic narratives on Italian video art of the seventies, verifying their genealogy, the sources used and the accuracy of the narrated facts. For the selection of the corpus, it was decided to analyze in particular monographic volumes dealing with the history of the origins of video art in Italy. The aim was, in fact, to get a wide range of types of "narrations", as in the case of contemporary art and architecture magazines, which are examined in the second part of the essay. After the selection, for an analytical and comparative study of the various historiography, the essay focuses only on the Terza Biennale Internazionale della Giovane Pittura. Gennaio ’70. Comportamenti, oggetti e mediazioni (Third International Biennial of Young Painting. January '70. Behaviors, Objects and Mediations, 1970, Bologna), the exhibition which - after Lucio Fontana's pioneering experiments - is said to be the first sign of the arrival of videotape in Italy (called at the time videorecording), curated by Renato Barilli, Tommaso Trini, Andrea Emiliani and Maurizio Calvesi. The narration given so far of this exhibition appeared more mythological than historical and could be compared structurally to that of the many numerous beginnings that historiographyies on international video art identify as ‘first’ and ‘generative’. In the first part of the essay the 'facts' related to Gennaio ’70, as narrated by historiography on video art, are compared. In the second part the survey is carried out through some of the direct sources identified during the research, with the aim of answering to questions raised by the comparison between historiographies. Concluding, it is important to underline that the tapes containing the videos transmitted have not been found and seem to have disappeared since the ending of the exhibition. Nevertheless, the deepening of the works and documentation transmitted during the exhibition is possible thanks to other types of sources which give us many valuable information regarding video techniques and practices at the beginning of 1970 in Italy.

WEIGHT GAINS IN THE FIRST FOUR WEEKS OF INFANCY: A COMPARISON OF THREE DIETS

PEDIATRICS ◽  
1956 ◽  
Vol 18 (3) ◽  
pp. 362-368
Author(s):  
Ruth T. Gross ◽  
Lincoln E. Moses
Keyword(s):  
Human Milk ◽  
Statistical Methods ◽  
Full Term ◽  
Clinical Judgement ◽  
Careful Selection ◽  
Term Infants ◽  
Weight Gains ◽  
The Many ◽  
Selection Of

Four hundred seven healthy, full-term infants were divided into three groups and fed, respectively, a formula of evaporated milk and water with 5% carbohydrate; human milk; and a special modified evaporated milk designed to simulate human milk. No other foods were added to the diet. A comparison of the three groups was made, based on weight gains from birth to the end of the first 4 weeks. The conclusions refer only to weight gains; no attempt was made to determine the superiority of any particular diet. The data show no significant differences in the 4-week weight gains among the three groups of infants, although sensitive statistical methods could be validly applied to the problem. These methods are explained. The authors wish to emphasize the many variables which must be taken into account in a study of this sort; the necessity for careful selection of valid statistical methods; the importance of critical clinical judgement in the evaluation of the results.

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