342 research outputs found
Synthetic approaches to multifunctional indenes
The synthesis of multifunctional indenes with at least two different functional groups has not yet been extensively explored. Among the plausible synthetic routes to 3,5-disubstituted indenes bearing two different functional groups, such as the [3-(aminoethyl)inden-5-yl)]amines, a reasonable pathway involves the (5-nitro-3-indenyl)acetamides as key intermediates. Although several multistep synthetic approaches can be applied to obtain these advanced intermediates, we describe herein their preparation by an aldol-type reaction between 5-nitroindan-1-ones and the lithium salt of N,N-disubstituted acetamides, followed immediately by dehydration with acid. This classical condensation process, which is neither simple nor trivial despite its apparent directness, permits an efficient entry to a variety of indene-based molecular modules, which could be adapted to a range of functionalized indanones
Azolium-based systems: application of an anion exchange resin (A- form) method and 1H NMR analysis of the charged-assisted (C<br>H)+·anion hydrogen bonds
The counteranion exchange of quaternary 1,2,3-triazolium salts was examined using a simple method that permitted halide ions to be swap for a variety of anions using an anion exchange resin (A¯ form). The method was applied to 1,2,3-triazolium-based ionic liquids and the iodideto- anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Additionally, an anion exchange resin (N3¯ form) was used to obtain the benzyl azide from benzyl halide under mild reaction. Likewise, following a similar protocol, bis(azidomethyl)arenes were also synthesized in excellent yields. The results of a proton NMR spectroscopic study of simple azolium-based ion pairs are discussed, with attention focused on the significance of the charged-assisted (CH)+···anion hydrogen bonds of simple azolium systems such as 1-butyl-3-methylimidazolium and 1-benzyl-3-methyl-1,2,3-triazolium salts
1,2-Diaryl(3-pyridyl)ethanone Oximes. Intermolecular Hydrogen Bonding Networks Revealed by X-ray Diffraction
The synthesis of a set of 1-aryl-2-aryl(3-pyridyl)ethanones 1-5 and thecorresponding ketoximes 6-9 is reported. Structural studies of oximes 6, 7 and 9 wereperformed in solution using 1H-NMR and in the solid state by X-ray crystallography,providing evidence of H-bonding networks. The crystal packing was controlled byhomomeric intermolecular oxime···oxime H-bond interactions for 6 and cooperativeoxime···N(pyridyl) and CH/π interactions for 7 and 9. Keywords: Oximes; ethanones; hydrogen bonds; self-assembly; X-ray diffraction crystalograph
Biotic Elicitors in Adventitious and Hairy Root Cultures: A Review from 2010 to 2022
One of the aims of plant in vitro culture is to produce secondary plant metabolites using plant cells and organ cultures, such as cell suspensions, adventitious, and hairy roots (among others). In cases where the biosynthesis of a compound in the plant is restricted to a specific organ, unorganized systems, such as plant cell cultures, are sometimes unsuitable for biosynthesis. Then, its production is based on the establishment of organ cultures such as roots or aerial shoots. To increase the production in these biotechnological systems, elicitors have been used for years as a useful tool since they activate secondary biosynthetic pathways that control the flow of carbon to obtain different plant compounds. One important biotechnological system for the production of plant secondary metabolites or phytochemicals is root culture. Plant roots have a very active metabo-lism and can biosynthesize a large number of secondary compounds in an exclusive way. Some of these compounds, such as tropane alkaloids, ajmalicine, ginsenosides, etc., can also be biosyn-thesized in undifferentiated systems, such as cell cultures. In some cases, cell differentiation and organ formation is necessary to produce the bioactive compounds. This review analyses the biotic elicitors most frequently used in adventitious and hairy root cultures from 2010 to 2022, focusing on the plant species, the target secondary metabolite, the elicitor and its concentration, and the yield/productivity of the target compounds obtained. With this overview, it may be easier to work with elicitors in in vitro root cultures and help understand why some are more effective than others
Unlocking the potential of olive residues for functional purposes: update on human intervention trials with health and cosmetic products
Olive mill waste (OMW) is a promising source of valuable compounds such as polyphenols, terpenes, sterols, and other bioactivecompounds, which are of interest to the pharmaceuticals and cosmeceutical industries. This review examines the potential ofOMW extracts for health and beauty applications based on evidence reports from human clinical trials. The results achievedto date indicate health-enhancing properties, but little is known about the underlying mechanisms of action, dose–responserelationships, and long-term impacts. Therefore, while olive by-products, extracted using eco-friendly methods, present oppor-tunities for the development of high-value health and cosmetic products, further studies are necessary to determine the fullrange of their effects and establish specific therapeutic strategies
Debate sobre la Ley Federal del Trabajo
Se recuerda con preocupación la forma como la política laboral instrumentada en el sexenio de Carlos Salinas impuso "soluciones" a cada uno de los conflictos obrero patronales, soluciones adoptadas al margen y por sobre la normatividad laboral de esos días.
Se abre boca a la discusión sin pensar que los avances tengan alguna significación, ya que muy pronto se llegó a ciertas conclusiones colectivas, de definición y proposición de temáticas tales como la libertad sindical, las condiciones de trabajo y la efectividad de las nuevas normas.
Estas propuestas y reflexiones hechas en un contexto en el que la productividad en el trabajo y la capacitación para su realización, son preocupaciones de los trabajadores y sus sindicatos, en que la búsqueda de una salida a la crisis económica que padecemos puede ser encontrada sin mayores sacrificios que los que ya padece la clase trabajadora y en función a un interés nacional y popular
An Impossibility Theorem in Matching Problems
This paper studies the possibility of strategy-proof rules yielding satisfactory solutions to matching problems. Alcalde and Barberá (1994) show that effcient and individually rational matching rules are manipulable in the one-to-one matching model. We pursue the possibility of strategy-proof matching rules by relaxing effciency to the weaker condition of respect for unanimity. Our first result is positive. We prove that a strategy-proof rule exists that is individually rational and respects unanimity. However, this rule is unreasonable in the sense that a pair of agents who are the best for each other are matched on only rare occasions. In order to explore the possibility of better matching rules, we introduce the natural condition of 'respect for pairwise unanimity.' Respect for pairwise unanimity states that a pair of agents who are the best for each other should be matched, and an agent wishing to stay single should stay single. Our second result is negative. We prove that no strategy-proof rule exists that respects pairwise unanimity. This result implies Roth (1982) showing that stable rules are manipulable. We then extend this to the many-to-one matching model
How does a cadaver model work for testing ultrasound diagnostic capability for rheumatic-like tendon damage?
To establish whether a cadaver model can serve as an effective surrogate for the detection of tendon damage characteristic of rheumatoid arthritis (RA). In addition, we evaluated intraobserver and interobserver agreement in the grading of RA-like tendon tears shown by US, as well as the concordance between the US findings and the surgically induced lesions in the cadaver model. RA-like tendon damage was surgically induced in the tibialis anterior tendon (TAT) and tibialis posterior tendon (TPT) of ten ankle/foot fresh-frozen cadaveric specimens. Of the 20 tendons examined, six were randomly assigned a surgically induced partial tear; six a complete tear; and eight left undamaged. Three rheumatologists, experts in musculoskeletal US, assessed from 1 to 5 the quality of US imaging of the cadaveric models on a Likert scale. Tendons were then categorized as having either no damage, (0); partial tear, (1); or complete tear (2). All 20 tendons were blindly and independently evaluated twice, over two rounds, by each of the three observers. Overall, technical performance was satisfactory for all items in the two rounds (all values over 2.9 in a Likert scale 1-5). Intraobserver and interobserver agreement for US grading of tendon damage was good (mean κ values 0.62 and 0.71, respectively), with greater reliability found in the TAT than the TPT. Concordance between US findings and experimental tendon lesions was acceptable (70-100 %), again greater for the TAT than for the TPT. A cadaver model with surgically created tendon damage can be useful in evaluating US metric properties of RA tendon lesions
Freedom of choice: John Stuart Mill and the tree of life
This essay deals with the notion and content of freedom of choice proposing a new set up and a new family of measures for this concept which is, indeed, an ethical value of paramount importance in a well ordered and open society. Following some ideas of John StuartMill, we propose that freedom of choice has to be understood not in a single stage of choice, but in the ordered collection of choices that a person can make in her life.We then suggest to represent a life in a tree structure, where each node
represents a state of life and the edges between nodes will represent possible decisions in life. In this new framework, we propose a set of axioms that imply the following family of measures of lifetime’s freedom of choice: the lifetime’s freedom of choice has to be evaluated by a weighted sum of all possible states of life an individual might visit, with weights representing the number of decisions the individual took to reach that state.Financial support
from the Spanish Ministry of Education through grants ECO2008-04756, ECO2009-11213, ECO2009-
12836, Ramon y Cajal program, FEDER, and the Barcelona Economics Program of CREA is gratefully
acknowledged
- …