Aristotle and Galen on sex difference and reproduction: a new approach to an ancient rivalry

[I]n contrast to Aristotle's male oriented explanation of procreation the Galenic was 'feminist' inasmuch as both sexes were presented as contributing equally in conception and accordingly both had to experience pleasure... Anatomically, the two sexes were presented in Galenic accounts as complementary, the difference being that the man's genitalia were on the outside and the woman's on the inside. The clitoris was likened to the penis and the ovaries considered 'testicles' or 'stones' that produced seed. The male seed was, it is true, depicted by Galenists as superior in having 'spiritual' qualities lacking in the female, but Galen's reproductive schema was far more egalitarian than Aristotle's. (McLaren, 1985, p. 327)     

Interpreting Aristotle on mixture: problems about elemental composition from Philoponus to Cooper

Aristotle’s On generation and corruption raises a vital question: how is mixture, or what we would now call chemical combination, possible? It also offers an outline of a solution to the problem and a set of criteria that a successful solution must meet. Understanding Aristotle’s solution and developing a viable peripatetic theory of chemical combination has been a source of controversy over the last two millennia. We describe seven criteria a peripatetic theory of mixture must satisfy: uniformity, recoverability, potentiality, equilibrium, alteration, incompleteness, and the ability to distinguish mixture from generation, corruption, juxtaposition, augmentation, and alteration. After surveying the theories of Philoponus (d. 574), Avicenna (d. 1037), Averroes (d. 1198), and John M. Cooper (fl. circa 2000), we argue for the merits of Richard Rufus of Cornwall’s theory. Rufus (fl. 1231-1256) was a little known scholastic philosopher who became a Franciscan theologian in 1238, after teaching Aristotelian natural philosophy as a secular master in Paris. Lecturing on Aristotle’s De generatione et corruptione, around the year 1235, he offered his students a solution to the problem of mixture that we believe satisfies Aristotle’s seven criteria.     

Aristotle, Copernicus, Bruno: centrality, the principle of movement and the extension of the Universe

This paper¹ studies the different conceptions of both centrality and the principle or starting point of motion in the Universe held by Aristotle and later on by Copernicanism until Kepler and Bruno. According to Aristotle, the true centre of the Universe is the sphere of the fixed stars. This is also the starting point of motion. From this point of view, the diurnal motion is the fundamental one. Our analysis gives pride of place to De caelo II, 10, a chapter of Aristotle’s text which curiously allows an ‘Alpetragian’ reading of the transmission of motion.In Copernicus and the Copernicans, natural centrality is identified with the geometrical centre and, therefore, the Sun is acknowledged as the body through which the Deity acts on the world and it also plays the role of the principle and starting point of cosmic motion. This motion, however, is no longer diurnal motion, but the annual periodical motion of the planets. Within this context, we pose the question of to what extent it is possible to think that, before Kepler, there is a tacit attribution of a dynamic or motive role to the Sun by Copernicus, Rheticus, and Digges.For Bruno, since the Universe is infinite and homogeneous and the relationship of the Deity with it is one of indifferent presence everywhere, the Universe has no absolute centre, for any point is a centre. By the same token, there is no place that enjoys the prerogative of being—as being the seat of God—the motionless principle and starting point of motion.     

Perillartine and some derivatives: Clarification of structures

Riassunto Viene confermato che la struttura dell'agente dolcificante perillartina è quella di unasim ossima. Il tentativo di ottenere l'isomeroanti per azione dell'acido cloridrico ha condotto invece all'addotto tra HCl e gruppo isopropenilico, mentre il trattamento con trifluoruro di boro ha provocato solo la migrazione del doppio legame per formare l'analogo derivato dell'1, 3-cicloesadiene.     

Sickle cell vasoocclusion: Many issues and some answers

The pathophysiology of sickle (SS) cell vasoocclusion is derived from the presence of hemoglobin S (HbS) which forms polymeric fibers in the deoxygenated state. Nevertheless, phenotypic expression of sickle cell disease (i.e., clinical severity) shows marked individual variations and is influenced by genetic modifiers such as epistatic effects of linked and unlinked genes. Furthermore, the polymerization of HbS is central but not the only event, and is more likely a consequence of disruptions of the steady state of flow. The available evidence indicates that the vasoocclusive crisis is a microcirculatory event in which multiple factors could be involved. We present a model of vasoocclusion as a two step process in which adhesion of deformable cells occurs first, followed by obstruction induced by less deformable SS cells. This review discusses, in addition, rheologic and microcirculatory behavior of SS erythrocytes and the interacting role of vascular factors, red cell heterogeneity, deoxygenation rates, and red cell-endothelial interactions in the pathophysiology of SS cell vasoocclusion.     

Pre-Euclidean geometry and Aeginetan coin design: some further remarks

Some ancient Greek coins from the island state of Aegina depict peculiar geometric designs. Hitherto they have been interpreted as anticipations of some Euclidean propositions. But this paper proposes geometrical constructions which establish connections to pre-Euclidean treatments of incommensurability. The earlier Aeginetan coin design from about 500 bc onwards appears as an attempt not only to deal with incommensurability but also to conceal it. It might be related to Plato’s dialogue Timaeus. The newer design from 404 bc onwards reveals incommensurability, namely in the context of ‘doubling the square’. It thereby covers the same topic but a different geometry as passages in Plato’s dialogue Meno (385 bc). This coin design incorporates important elements of ancient Greek geometrical analysis of the fifth century bc like the gnomon, Hippocrates’ squaring of the lunule (ca. 430 bc), and a geometrical version of monetary equivalence. Through this venue, the design’s conceptual lineage might be traced as far back as Heraclitus’ cosmology of about 500 bc.     

Of von Willebrand factor and platelets

Hemostasis and pathological thrombus formation are dynamic processes that require multiple adhesive receptor-ligand interactions, with blood platelets at the heart of such events. Many studies have contributed to shed light on the importance of von Willebrand factor (VWF) interaction with its platelet receptors, glycoprotein (GP) Ib-IX-V and αIIbβ3 integrin, in promoting primary platelet adhesion and aggregation following vessel injury. This review will recapitulate our current knowledge on the subject from the rheological aspect to the spatio-temporal development of thrombus formation. We will also discuss the signaling events generated by VWF/GPIb-IX-V interaction, leading to platelet activation. Additionally, we will review the growing body of evidence gathered from the recent development of pathological mouse models suggesting that VWF binding to GPIb-IX-V is a promising target in arterial and venous pathological thrombosis. Finally, the pathological aspects of VWF and its impact on platelets will be addressed.     

Invertebrate neuropeptides resembling vasotocin and some analogues: synthesis and pharmacological properties

The solid phase synthesis of three invertebrate vasopressin-oxytocin homologs: AVP-like factor, F1(1), ([Leu2, Thr4] AVT)2 isolated from subesophageal and thoracic ganglia of Locusta migratoria3, Arg-conopressin-S4. ([Ile2, Arg4] AVT), Lys-conopressin-G4 ([Phe2, Arg4] LVT), both isolated from the venom of fish-hunting marine snails of the genus Conus and six of their analogues is reported. These analogues are: [Arg4] AVT, [Ile2] AVT, [Leu2] AVT, [Phe2, Arg4] AVT, [Arg4] LVT and [Ile2, Arg4] LVT. All peptides were tested for antidiuretic and vasopressor activities.     

Of membranes and malaria: phospholipid asymmetry in Plasmodium falciparum-infected red blood cells

Cellular and Molecular Life Sciences - Malaria is a vector-borne parasitic disease with a vast impact on human history, and according to the World Health Organisation, Plasmodium parasites still...