Modern Synthesis Research Articles

Retinol (Vitamin A) and Its Derivatives: Synthesis and Applications

This paper systematically reviews the synthesis methods of retinol (Vitamin A) and its derivatives, along with their applications in skincare and pharmaceuticals. By examining traditional chemical synthesis pathways such as the Roche, BASF, and Rhone-Poulenc routes, as well as modern biological synthesis pathways, the paper highlights the advantages and limitations of each method, particularly in terms of improving synthesis efficiency, reducing production costs, and minimizing environmental impact. The paper also analyzes the application of retinol derivatives in skincare, including their roles in anti-aging, skin barrier repair, skin whitening, and even tone. Additionally, the paper discusses methods to enhance the stability and bioactivity of retinol. Future directions include further innovation in synthesis techniques, the development of new derivatives, and new pharmaceutical applications of retinol. The paper concludes that retinol and its derivatives hold great promise in the beauty and health sectors, though further research is needed to overcome current challenges and promote wider application.

The modern synthesis and "Progress" in evolution: a view from the journal literature.

The concept of "progress" in evolutionary theory and its relationship to a putative notion of "Progress" in a global, normatively loaded sense of "change for the better" have been the subject of debate since Darwin admonished himself in a marginal note to avoid using the terms 'higher' and 'lower.' While an increase in some kind of complexity in the natural world might seem self-evident, efforts to explicate this trend meet notorious philosophical difficulties. Numerous historians pin the Modern Synthesis as a pivotal moment in this history; Michael Ruse even provocatively hypothesizes that Ernst Mayr and other "architects" of the Synthesis worked actively to eliminate Progress from evolutionary biology's scientific purview. I evaluate these claims here with a textual analysis of the journals Evolution and Proceedings of the Royal Society B (a corpus of 27,762 documents), using a dynamic topic modeling approach to track the fate of the term 'progress' across the Modern Synthesis. The claim that this term declines in importance for evolutionary theorizing over this period can, indeed, be supported; more tentative evidence is also provided that the discussion of 'progress' is largely absent from the British context, emphasizing the role of American paleontology in the rise and fall of 'progress' in 20th-century evolutionary biology.

The historical transformation of individual concepts into populational ones: an explanatory shift in the gestation of the modern synthesis.

In this paper, I will conduct three interrelated analyses. First, I will develop an analysis of various concepts in the history of biology that used to refer to individual-level phenomena but were then reinterpreted by the Modern Synthesis in terms of populations. Second, a similar situation can be found in contemporary evolutionary theory. While different approaches reflect on the causal role of developing organisms in evolution, proponents of the Modern Synthesis refrain from any substantial change by reinterpreting and explaining individual-level phenomena from a population perspective. Finally, I will approach these historical and contemporary debates by arguing for the statistical reading of natural selection, which holds that explanations by natural selection are statistical. My main conclusion is that the historical conceptual reinterpretations belong to a new explanatory strategy developed by the Modern Synthesis based on population thinking. Adopting the statistical point of view has three advantages for the issues discussed in this paper. First, understanding historical conceptual change as part of an explanatory shift fits with the emergence of population biology as a discipline that employs statistical methods. Second, concerning current debates in evolutionary biology, the statisticalist reading can validate the goal of both sides of the dispute. It ascribes an invaluable role to the population statistical explanation of the MS and also commends the study of developmental and organismal causes of adaptive evolution. Finally, the division of explanatory roles in evolutionary biology, embarrassed by statisticalism, can be related to the different interpretations that important biological concepts have undergone throughout history and contemporary biology, i.e., that the division of explanatory roles allows for a division of conceptual interpretations.

The extended evolutionary synthesis: An integrated historical and philosophical examination

AbstractAmong biologists and philosophers, there is an ongoing debate over the Modern Synthesis and the Extended Evolutionary Synthesis. Some argue that our current evolutionary biology is in need of (at least) some substantial revision or nontrivial extension, while others maintain that the Modern Synthesis remains the foundational framework for evolutionary biology. It has been widely debated whether the Extended Evolutionary Synthesis provides a more promising framework than the Modern Synthesis. The nature and methodological implications of the Extended Evolutionary Synthesis were also examined. This paper offers an integrated historical and philosophical examination of the debate over the Extended Evolutionary Synthesis. It reviews the development of evolutionary biology of the twentieth century. It argues that there are substantial conceptual and theoretical differences between the Modern Synthesis and the Extended Evolutionary Synthesis, but they are not incommensurable paradigms in the Kuhnian sense. It also argues for a functional approach to the debate over these two frameworks of evolutionary theory.

Tangled Banks, Braided Rivers and Complex Hierarchies: Beyond Microevolution and Macroevolution.

Ever since the Modern Synthesis, a debate about the relationship between microevolution and macroevolution has persisted - specifically, whether they are equivalent, distinct, or explain one another. How one answers this has become shorthand for a much broader set of theoretical debates in evolutionary biology. Here, we examine microevolution and macroevolution in the context of the vast proliferation of data, knowledge, and theory since the advent of the Modern Synthesis. We suggest that traditional views on microevolution and macroevolution are too binary and reductive. For example, patterns and processes are not confined to micro- and macro- domains; they are interconnected at various temporal and spatial scales and across hierarchical entities. Further, biological entities have variably fuzzy boundaries, and evolutionary processes that influence macroevolution occur at micro- and macro- levels. In addition, these conceptual advances in phylodynamics have yet to be fully integrated with contemporary macroevolutionary approaches. Finally, holding microevolution and macroevolution as distinct domains thwarts synthesis and collaboration on important research questions. We propose that the focal entities and processes considered by evolutionary studies be contextualized within the newfound complexity of the multidimensional, multi-modal, multi-level phylogenetic system.

Stellane at the Forefront: Derivatization and Reactivity Studies of a Promising Saturated Bioisostere of ortho-Substituted Benzenes.

This work highlights stellane's cage stability and derivatization opportunities. A diverse range of building blocks were synthesized using modern synthesis protocols to demonstrate stellane's reactivity and chemical tolerance across different reaction systems, proving its promise as a bioisosteric scaffold. It can be utilized in scaffold-based molecular design and is superior in terms of topological precision compared to existing ortho isosteres, as well as monosubstituted benzene mimetics, holding the potential to become a robust platform for future medicinal chemistry studies.

Darwin and the White Shipwrecked Sailor: Beyond Blending Inheritance and the Jenkin Myth.

This paper revisits Fleeming Jenkin's anonymous review of Charles Darwin's Origin of Species, published in the North British Review in June 1867. This review is usually revered for its impact on Darwin's theory of descent with modification. Its classical interpretation states that Jenkin, a Professor of Engineering at the University of Edinburgh, made a compelling case against natural selection based on the fact of "blending inheritance" and the "swamping" of advantageous variations. Those themes, however, are strikingly absent from Jenkin's text. They were later read into Jenkin's text by scholars trying to explain how Darwinian selection was reconciled with Mendelian genes and the birth of the Modern Synthesis. While many scholars have tried to measure Jenkin's effect on Darwin, the value of the 1867 review remains unclear. This paper re-examines its content and concludes that Jenkin's "able review" was in fact written by an engineer whose competencies in biology were very low. Focusing on the figure of the shipwrecked white sailor isolated on an island inhabited by Black people, this paper also underlines the racial assumptions behind Jenkin's review. "Blending inheritance" is thus a theme linked to theoretical reworkings on the question of race and skin colors, taking its root in Galton's typology of heredity. Darwin was probably mostly unimpressed by Jenkin's review. The problems raised by the review were not so much "blending inheritance" and "swamping" but a conundrum of problems related to the effects of intercrossing on variation and reversion.

An Approach to Evolutionary Sociology and its Implications for Theorizing on Socio-Cultural Evolution

A theoretical research program is outlined that seeks to use the Modern Synthesis in explaining human evolution, but also recognizes its limitations in explaining the evolution of socio-cultural systems. The universe, from a human perspective, is composed of physical, biological, and socio-cultural dimensions, each revealing unique properties and dynamics. In the case of the socio-cultural universe, modern evolutionary theory is relevant for some explanations, but not to the degree assumed by socio-biology, evolutionary psychology, and even co-evolutionary models. The program proposed is built around social network theory, cladistic analysis, and comparative neuro-anatomy, and outlines where biological analysis is appropriate and useful. An understanding of the biological basis of human behavior will allow sociologists to develop theoretical approaches to explaining the emergent properties of the socio-cultural universe. The strategy outlined will allow us to see what a mature evolutionary sociology can do: develop abstract theoretical laws about the dynamics of selection on socio-cultural formations in human societies.

Cooperative genes in smart systems: Toward an inclusive new synthesis in evolution

For more than half a century, biologist Julian Huxley's term, the “Modern Synthesis”, has been used as a label for a model of biological evolution where genetic influences are viewed as a principal source of creativity and change. Over the years, as evidence has accumulated that there are many other, far more important factors at work in evolution, theoretical “compromises,” such as the so-called “Extended Synthesis”, have been proposed. This is no longer tenable. It is time to abandon the Modern Synthesis, and its doppelganger “The Selfish Gene”. Here is the case for a new, multi-faceted, open-ended, “inclusive” evolutionary synthesis, where living systems themselves are recognized as purposeful (teleonomic) “agents” and cooperative effects (synergies) of various kinds are seen as all-important influences.

Nitrodiazene oxides: a unique nitrogen- and oxygen-containing functional group.

Nitrogen-/oxygen-containing functional groups (N/O groups) may be found in a wide variety of areas such as agriculture, drug design and energetic materials. Exploring the chemistry and synthesis of N/O groups is desirable as compounds containing their functionality may prove to be invaluable in a variety of fields. A unique N/O functional group which may offer additional insight into the design of high-heteroatom content systems is the 2-nitrodiazene-1-N-oxide group (NDO group). While unique on their own, NDOs combine the well-known azoxy (N(O)=N) and nitro (-NO2) groups into a single unique N/O functional group. Although NDOs may offer superior densities and enthalpies of formations relative to their nitro counterparts, NDOs have been significantly less investigated than their nitro-bearing counterparts. This work will discuss NDOs in chemical literature from their initial discovery to modern synthesis techniques, energetic properties and chemical stability.

The nature of nurture: Darwinian and mendelian perspectives.

Two perspectives on the nature of nurture are reviewed, one Mendelian and the other Darwinian, in an effort to draw links between the two and, thereby, integrate them in a developmental modern synthesis, mirroring the one that took place in biology early in the last century. Thus, the heritability of environmental measures and gene-X-environment interaction are discussed with respect to Mendelian nature before turning attention to Darwinian nature and thus the development of reproductive strategies and differential susceptibility to environmental influences. Conclusions are drawn with respect to both frameworks indicating that it is time to abandon the biology-is-destiny resistance to both approaches to studying and thinking about development, especially when it comes to the nature of nurture. Implications for the future development of the field of developmental psychopathology are highlighted.

Speciation, natural selection, and networks: three historians versus theoretical population geneticists.

In 1913, the geneticist William Bateson called for a halt in studies of genetic phenomena until evolutionary fundamentals had been sufficiently addressed at the molecular level. Nevertheless, in the 1960s, the theoretical population geneticists celebrated a "modern synthesis" of the teachings of Mendel and Darwin, with an exclusive role for natural selection in speciation. This was supported, albeit with minor reservations, by historians Mark Adams and William Provine, who taught it to generations of students. In subsequent decades, doubts were raised by molecular biologists and, despite the deep influence of various mentors, Adams and Provine noted serious anomalies and began to question traditional "just-so-stories." They were joined in challenging the genetic orthodoxy by a scientist-historian, Donald Forsdyke, who suggested that a "collective variation" postulated by Darwin's young research associate, George Romanes, and a mysterious "residue" postulated by Bateson, might relate to differences in short runs of DNA bases (oligonucleotides). The dispute between a small network of historians and a large network of geneticists can be understood in the context of national politics. Contrasts are drawn between democracies, where capturing the narrative makes reversal difficult, and dictatorships, where overthrow of a supportive dictator can result in rapid reversal.

New Insights on the Chemical Origin of Life: The Role of Aqueous Polymerization of N-carboxyanhydrides (NCA).

At the origin, the emergence of proteins was based on crucial prebiotic stages in which simple amino acids-based building blocks spontaneously evolved from the prebiotic soup into random proto-polymers called protoproteins. Despite advances in modern peptide synthesis, these prebiotic chemical routes to protoproteins remain puzzling. We discuss in this perspective how polymer science and systems chemistry are reaching a point of convergence in which simple monomers called N-carboxyanhydrides would be able to form such protoproteins via the emergence of a protometabolic cycle involving aqueous polymerization and featuring macromolecular Darwinism behavior.

Evolutionary feedback from the environment shapes mechanisms that generate genome variation.

Darwin recognized that 'a grand and almost untrodden field of inquiry will be opened, on the causes and laws of variation.' However, because the Modern Synthesis assumes that the intrinsic probability of any individual mutation is unrelated to that mutation's potential adaptive value, attention has been focused on selection rather than on the intrinsic generation of variation. Yet many examples illustrate that the term 'random' mutation, as widely understood, is inaccurate. The probabilities of distinct classes of variation are neither evenly distributed across a genome nor invariant over time, nor unrelated to their potential adaptive value. Because selection acts upon variation, multiple biochemical mechanisms can and have evolved that increase the relative probability of adaptive mutations. In effect, the generation of heritable variation is in a feedback loop with selection, such that those mechanisms that tend to generate variants that survive recurring challenges in the environment would be captured by this survival and thus inherited and accumulated within lineages of genomes. Moreover, because genome variation is affected by a wide range of biochemical processes, genome variation can be regulated. Biochemical mechanisms that sense stress, from lack of nutrients to DNA damage, can increase the probability of specific classes of variation. A deeper understanding of evolution involves attention to the evolution of, and environmental influences upon, the intrinsic variation generated in gametes, in other words upon the biochemical mechanisms that generate variation across generations. These concepts have profound implications for the types of questions that can and should be asked, as omics databases become more comprehensive, detection methods more sensitive, and computation and experimental analyses even more high throughput and thus capable of revealing the intrinsic generation of variation in individual gametes. These concepts also have profound implications for evolutionary theory, which, upon reflection it will be argued, predicts that selection would increase the probability of generating adaptive mutations, in other words, predicts that the ability to evolve itself evolves.

Особенности инициирования подвижным источником энергии реакций в плоском слое, расположенном на подложке

In the conditions of the surface treatment of materials and coating application using mixtures of powders (metals, metals and nonmetals, metals and oxides) capable of chemical interactions, problems similar to those of solid-phase combustion theory arise. Currently available publications, which confirm the fact of the reactions, are limited to the analysis of the obtained structures, mechanical properties and the statement of the presence of certain compounds and phases. We present the reduced models for the synthesis of composites on a planar substrate allowing us to analyze qualitative effects. The first model is one-dimensional with a total reaction. The second model corresponds to the synthesis of a matrix-inclusion-type composite. The process is assumed to be driven by a moving heat source. Both models take into account the properties of the substrate. The transition to dimensionless variables reveals both the parameters characteristic of macrokinetics and the parameters typical for modern material synthesis technologies. The numerical solution shows that in the presence of a mobile heat source the reaction zone is sufficiently wide, and the temperature dynamics in general is dissimilar to that of combustion processes. It is shown that there is a parameter region in which partial transformation is observed. Two characteristics of the synthesis process have been determined - the time of the reaction initiation and the time of half-transformation (for a sample of finite size). Taking into account detailed kinetics, similar studies allow us to predict the qualitative composition of synthesis products when changing the conditions and initial composition of powder mixtures.

Preparation of N-heterylarenes from the perspective of phenylhydrazine-based under the principles green chemistry

Herein, modern green synthesis approaches are studied to assemble N-heterylarenes scaffolds via a non-catalyzed intramolecular 5/6-exo-dig cyclocondensation reaction based on the in-situ generation of arenehydrazonopentan-/hexan-2-one. Accordingly, the formation of two N-heteryl moieties, pyrazol-1-yl and pyridazin-1(4H)-yl, was initially studied. Therefore, appropriate fluorophenyl was first converted into their respective phenylhydrazine by SNAr reaction and then reacted with different trigonal carbonyl bielectrophiles (-CO-, -CO2R, and -CO2H) in ethanol in the presence of US, MW, IR, and an IR· US irradiation mixture. Cyclic nitrogenous cores were best obtained when subjected to microwave irradiation with ketone and arylhydrazine as starting reagents, allowing them to get excellent yields quickly. Arylhydrazine reactants featuring Π-donor groups underwent the best 5/6-exo-dig type annulment reaction. Presumably, the observed improvements in EDG-dependent reaction efficiency reflect changes in the nucleophilicity of arylhydrazines intermediates as α-nucleophilic reactants.

Enantioselective synthesis of [1,1'-binaphthalene]-8,8'-diyl bis(diphenylphosphane) and its derivatives.

Two 8,8' disubstituted binaphthyl ligands have been designed and synthesized in 3.1% and 11.4% overall yield, respectively. X-ray structure analysis demonstrated that a unique chiral microenvironment was created. With the assistance of a new aggregation-induced polarization (AIP) technology, chiral aggregates were determined as the fraction of polar solvent increased in the nonpolar/polar solvent system, which indicated their potential in modern asymmetric synthesis and catalysis.

Glycosylation of n-pentenyl glycosides using bromodiethylsulfonium salt as an activator: interception of the glycosyl intermediate by chloride ion transfer.

Utilization of n-pentenyl glycosides (NPGs) in modern carbohydrate synthesis may be hindered by their sluggish activation, which results from reversible halogenation and cyclization processes. Bromodiethylsulfonium bromopentachloroantimonate (BDSB) has been previously shown to be a powerful brominating agent for the cation-π polyene cyclization of less reactive and electron-poor polyenes. This study demonstrates the activation of NPGs using BDSB as a powerful brominating agent. BDSB effectively activates the terminal olefins of NPGs and the reaction proceeds through 5-exo-tet cyclization, offering a rapid and mild approach for glycosylation with a wide range of glycosyl donors, including n-pentenyl mannoside, n-pentenyl galactoside, and n-pentenyl glucoside. The success of this approach derives from the chloride ion transfer from the nonnucleophilic SbCl5Br anion to the glycosyl intermediate, which disrupts the equilibrium and produces a glycosyl chloride intermediate that is smoothly converted to 22 coupling products, with yields ranging from moderate to excellent (49-100%). The β-selective glycosylation is accomplished when employing NPGs equipped with a neighboring participating group. The practicality of the BDSB-activated glycosylation is demonstrated by a gram-scale synthesis. This study showcases BDSB as a potent activator for NPG glycosylation through the interception of a glycosyl intermediate that diminishes the equilibration during halogenation and 5-exo-tet cyclization.

Protein desulfurization and deselenization.

Methods enabling the dechalcogenation of thiols or selenols have been investigated and developed for a long time in fields of research as diverse as the study of prebiotic chemistry, the engineering of fuel processing techniques, the study of biomolecule structures and function or the chemical synthesis of biomolecules. The dechalcogenation of thiol or selenol amino acids is nowadays a particularly flourishing area of research for being a pillar of modern chemical protein synthesis, when used in combination with thiol or selenol-based chemoselective peptide ligation chemistries. This review offers a comprehensive and scholarly overview of the field, emphasizing emerging trends and providing a detailed and critical mechanistic discussion of the dechalcogenation methods developed so far. Taking advantage of recently published reports, it also clarifies some unexpected desulfurization reactions that were observed in the past and for which no explanation was provided at the time. Additionally, the review includes a discussion on principal desulfurization methods within the framework of newly introduced green chemistry metrics and toolkits, providing a well-rounded exploration of the subject.

Real Competition and Profit Rate Equalisation: Theory and Evidence from the Norwegian Economy

The existence of long-run profitability differentials in market economies is a fundamental question that all traditions of economic thought since the times of the classical economists have dealt with in some form or another. In consideration of the modern synthesis of the classical views on competition into what has come to be known as the Theory of Real Competition, this article presents both a consistent theoretical basis from which to argue in favour of the tendential elimination of profitability premia across industries, as well as empirical evidence pointing to such conclusion from the Norwegian economy. The data, which covers 26 industries across nearly five decades (1971–2017), is used to estimate average and incremental total long-run profit rate differentials following two distinct methodologies. The first method has been commonly used in the prior literature, and the second has been newly systematised by this study’s author. Both methods are critically scrutinised, and their results compared to allow for a more robust conclusion. The findings suggest that average profit rates exhibit a weak tendency towards equalisation in Norway, and that such tendency is much stronger for incremental profit rates.