https://riviste.fupress.net/index.php/subs/issue/feed Substantia 2018-04-03T08:17:51+00:00 Pierandrea Lo Nostro pierandrea.lonostro@unifi.it Open Journal Systems <p style="text-align: justify;"><em>Substantia</em> is a peer-reviewed academic international journal dedicated to the history and philosophy of Chemistry and edited by the University of Florence. Topics of interest include traditional and innovative perspectives in the development of Chemistry. Fundamentals and implications of chemical theories and related sciences, interdisciplinary works (highlighting the interconnections between Chemistry, other scientific disciplines, arts, technology, social and human sciences), contributions from unpublished sources are welcome. The journal is published open access and offers top quality original full papers, essays, experimental works, reviews, biographies and dissemination manuscripts. All contributions are in English.</p> https://riviste.fupress.net/index.php/subs/article/view/36 Why Chemists Need Philosophy, History, and Ethics 2018-03-29T09:57:37+00:00 Joachim Schummer js@hyle.org <p>Since many years national and international science organizations have recommended the inclusion of philosophy, history, and ethics courses in science curricula at universities. Chemists may rightly ask: What is that good for? Don’t primary and secondary school provide enough general education such that universities can focus on chemistry alone? Is that only a conservative call back to an antiquated form of higher education? Or do they want us to learn some “soft skills” that can at best improve our eloquence at the dinner table but is entirely useless in our chemical work? The answers depend on what you understand by chemistry, philosophy, history, and ethics.</p> 2018-03-26T00:00:00+00:00 ##submission.copyrightStatement## https://riviste.fupress.net/index.php/subs/article/view/37 Emulsion Thermodynamics – In from the Cold 2018-04-03T08:17:51+00:00 Stig E. Friberg stic30kan@gmail.com <p class="p1">Thermodynamics has played virtually no role in traditional emulsion research, because emulsions are inherently thermodynamically unstable. The problem with commercial emulsions needing to exist with none or only small changes during use and the industrial stability problem was resolved by formulating <em>colloidally stable</em> emulsions, i.e. the <em>rate </em>of destabilization was reduced. This approach was successful for single-oil emulsions, but encountered problems for double emulsions, for which the simultaneous stabilization of several interfaces within one drop encountered difficulties. Naturally, even for such an emulsion, colloid stability is the only option to stabilize the outer surface towards the continuous phase. In fact, the destabilization by flocculation/coalescence proceeds similarly to a single-oil emulsion. But experiments have demonstrated that complex emulsions with a thermodynamically stabilized inner interface <em>retain</em> the individual drop topology during the process. This result opens an avenue to significantly facilitate the formulation of a group of commercially important emulsions, because the cumbersome multiple emulsion stabilization is reduced to the more trivial single-oil emulsion case.</p> 2018-03-26T17:51:19+00:00 ##submission.copyrightStatement## https://riviste.fupress.net/index.php/subs/article/view/38 Finding Na,K-ATPase: I - From Cell to Molecule 2018-03-29T09:57:26+00:00 Hans-Jürgen Apell h-j.apell@uni-konstanz.de <p class="p1">The oppositely oriented concentration gradients of Na<sup>+</sup> and K<sup>+</sup> ions across the cell membrane as found in animal cells led to the requirement of an active ion-transport mechanism that maintains this steady-state condition. As solution of this problem the Na,K-ATPase was identified, a member of the P-type ATPase family. Its stoichiometry has been defined as 3 Na<sup>+</sup>/2 K<sup>+</sup>/1 ATP, and a class of Na,K-ATPase-specific inhibitors, cardiac steroids, was established, which allow the identification of this ion pump. In an effort lasting for several decades structural details were uncovered down to almost atomic resolution. The quaternary structure of the functional unit, either αβ heterodimer or (αβ)<sub>n</sub> complexes with n ≥ 2, is still under discussion.</p> 2018-03-26T17:52:08+00:00 ##submission.copyrightStatement## https://riviste.fupress.net/index.php/subs/article/view/39 Mechanistic Trends in Chemistry 2018-03-29T09:57:22+00:00 Louis Caruana SJ caruana@unigre.it <p class="p1"><span class="s1">During the twentieth century, the mechanistic worldview came under attack mainly because of the rise of quantum mechanics but some of its basic characteristics survived and are still evident within current science in some form or other. Many scholars have produced interesting studies of such significant mechanistic trends within current physics and biology but very few have bothered to explore the effects of this worldview on current chemistry. This paper makes a contribution to fill this gap. It presents first a brief historical overview of the mechanistic worldview and then examines the present situation within chemistry by referring to current studies in the philosophy of chemistry and determining which trends are still mechanistic in spirit and which are not.</span></p> 2018-03-26T17:52:50+00:00 ##submission.copyrightStatement## https://riviste.fupress.net/index.php/subs/article/view/40 Cognition and Reality 2018-03-29T09:57:18+00:00 F. Tito Arecchi tito.arecchi@ino.it <p class="p1">We discuss the two moments of human cognition, namely, <em>apprehension </em>(A),whereby a coherent perception emerges from the recruitment of neuronal groups, and <em>judgment</em>(B),that entails the comparison of two apprehensions acquired at different times, coded in a suitable language and retrieved by memory. (B) entails <em>self-consciousness, </em>in so far as the agent who expresses the judgment must be aware that the two apprehensions are submitted to his/her own scrutiny and that it is his/her task to extract a mutual relation. Since (B) lasts around 3 seconds, the semantic value of the pieces under comparison must be decided within that time. This implies a fast search of the memory contents. As a fact, exploring human subjects with sequences of simple words, we find evidence of a limited time window , corresponding to the memory retrieval of a linguistic item in order to match it with the next one in a text flow (be it literary, or musical, or figurative). While apprehension is globally explained as a Bayes inference, judgment results from an inverse Bayes inference. As a consequence, two hermeneutics emerge (called respectively circle and coil). The first one acts in a pre-assigned space of features. The second one provides the discovery of novel features, thus unveiling previously unknown aspects and hence representing the road to reality.</p> 2018-03-26T17:53:32+00:00 ##submission.copyrightStatement## https://riviste.fupress.net/index.php/subs/article/view/41 A Correspondence Principle 2018-03-29T09:57:15+00:00 Barry D. Hughes barrydh@unimelb.edu.au Barry W. Ninham barry.ninham@anu.edu.au <p>A single mathematical theme underpins disparate physical phenomena in classical, quantum and statistical mechanical contexts. This mathematical “correspondence principle”, a kind of wave–particle duality with glorious realizations in classical and modern mathematical analysis, embodies fundamental geometrical and physical order, and yet in some sense sits on the edge of chaos. Illustrative cases discussed are drawn from classical and anomalous diffusion, quantum mechanics of single particles and ideal gases, quasicrystals and Casimir forces.</p> <div data-canvas-width="181.1066666666667"><strong>Permission to reproduce:&nbsp;</strong>Republished from <em>Physica A</em>, <strong>2016</strong>, <em>443</em>, 495-517. With permission from Elsevier. Copyright 2016</div> 2018-03-26T17:55:07+00:00 ##submission.copyrightStatement## https://riviste.fupress.net/index.php/subs/article/view/42 From idea to acoustics and back again: the creation and analysis of information in music 2018-03-29T09:57:12+00:00 Joe Wolfe J.Wolfe@unsw.edu.au <p>The information in musical signals – including recordings, written music, mechanical or electronic storage files and the signal in the auditory nerve – are compared as we trace the information chain that links the minds of composer, performer and listener. The (uncompressed) information content of music increases during stages such as theme, development, orchestration and performance. The analysis of performed music by the ear and brain of a listener may reverse the process: several stages of processing simplify or analyse the content in steps that resemble, in reverse, those used to produce the music. Musical signals have a low algorithmic entropy, and are thus readily compressed. For instance, pitch implies periodicity, which implies redundancy. Physiological analyses of these signals use these and other structures to produce relatively compact codings. At another level, the algorithms whereby themes are developed, harmonised and orchestrated by composers resemble, in reverse, the means whereby complete scores may be coded more compactly and thus understood and remembered. Features used to convey information in music (transients, spectra, pitch and timing) are also used to convey information in speech, which is unsurprising, given the shared hard- and soft-ware used in production and analysis. The coding, however, is different, which may give insight into the way music is understood and appreciated.</p> 2018-03-26T17:56:59+00:00 ##submission.copyrightStatement## https://riviste.fupress.net/index.php/subs/article/view/43 Snapshots of chemical practices in Ancient Egypt 2018-03-29T09:57:10+00:00 Jehane Ragai jragain@aucegypt.edu <p>This article gives a historical overview of a number of chemical practices carried out by the Ancient Egyptians and shows that beyond being purely empirical, in more than one instance their methods suggest an understanding of the rudiments of modern day chemistry. A close analysis of some of their preparations indicates that Ancient Egyptians were familiar with the principles of oxidation and reduction, could control the pH of a solution and were successful in preparing novel compounds through a controlled technology of chemical synthesis. In the latter endeavor it is shown that these Ancient people embraced the scientific method, preceding Aristotle’s rejection in Ancient Greece of a purely deductive approach to scientific enquiry. Egyptian Blue, the only pigment synthesized by the Ancient Egyptians is also discussed, and attention is drawn to its potential future contributions to modern high-tech applications.</p> 2018-03-26T17:57:41+00:00 ##submission.copyrightStatement## https://riviste.fupress.net/index.php/subs/article/view/44 The “Bitul B’shishim (one part in sixty)”: is a Jewish conditional prohibition of the Talmud the oldest-known testimony of quantitative analytical chemistry? 2018-03-29T09:57:07+00:00 Federico Maria Rubino federico.rubino@unimi.it <p>Accomplishments of Hellenistic science and technology in some fields, such as mathematics, physical cosmology and engineering, has recently been re-evaluated and can be considered as of the same level that the scientific revolution in Western Europe reached at the beginning of the XVII century CE. Information on the level of chemical science is scanty; however, independent ancient sources such as the Jewish Talmud can yield significant clues. The still existing dietary laws include a practice to assess the acceptability of food mixtures with two complementary assessment techniques. One enforces a specific minimum mixing ratio (1:60) of unacceptable-to-acceptable ingredients, the other uses a sensory assessment to exclude the presence of a tasty unacceptable ingredient. This practice is likely the first historical example of quantitative analytical chemistry. This article collects clues that this approach is rooted in the implicit acceptance by Hellenistic chemical science of an atomic paradigm and on the awareness that interaction of different matter yields product that are different from the starting ones. Quantitative assessment of the presence of unacceptable ingredients by sensorial assessment or by mixing ratio likely points to a forgotten practice of Hellenistic experimental pharmacology and physiology to test the efficacy of drugs and poisons, that was performed in animals, with the use of a control group, and on human subjects.</p> 2018-03-26T17:58:21+00:00 ##submission.copyrightStatement## https://riviste.fupress.net/index.php/subs/article/view/45 Michael Faraday: a virtuous life dedicated to science 2018-03-29T09:57:32+00:00 Franco Bagnoli franco.bagnoli@unifi.it Roberto Livi null@null.com <p>We review the main aspects of the life of Michael Faraday and some of his main scientific discoveries. Although these aspects are well known and covered in many extensive treatises, we try to illustrate in a concise way the two main “wonders” of Faraday’s life: that the son of a poor blacksmith in the Victorian age was able to become the director the Royal Institution and member of the Royal Society, still keeping a honest and “virtuous” moral conduct, and that Faraday’s approach to many topics, but mainly to electrochemistry and electrodynamics, has paved the way to the modern (atomistic and field-based) view of physics, only relying on experiments and intuition. We included many excerpts from Faraday’s letters and laboratory notes in order to let the readers have a direct contact with this scientist.</p> 2018-03-26T00:00:00+00:00 ##submission.copyrightStatement##