Quale механіка як метафізична світоглядна концепція квантової механіки

The term Quale Mechanics is proposed here as describing the qualitative aspects of Quantum Mechanics that are susceptible of metaphysical considerations. The aim of Quale Mechanics is to distill the quantum discourse to its pillars in order to construct its proper – philosophical in nature – quale discourse. The framework of the discussion is initiated by revisiting the platonic approach of the manner in which knowledge is perceived/processed, and then by discussing the four sapiential stages before arriving at concept of the eide. The sensible-suprasensible dichotomy is exposed by contrasting aistheta to the eide. A discussion on the historical development and the foundation of the pillars of Quantum Mechanics is followed. This includes Planck’s solution for the black-body radiation problem with the introduction of quanta – in conflict with Newtonian physics – followed by Einstein’s explanation of the photoelectric effect and the implications involving the dual nature of light (particle vs. wave) and two generalizations of the quantum character of matter: the planetary model of the atom by Bohr, and the dual particle-wave character of electron demonstrated by de Broglie. The subsequent distillation of these semi-classical concepts into more abstract mathematical concepts by Heisenberg, Born, Dirac and Pauli are then reviewed – with Heisenberg’s uncertainty principle and with the concept of wavefunction as landmarks that unmistakably departs from the classical deterministic view of matter. A representative illustration of these achievements is given by the Casimir effect – with implications for gravity and an illustration of how vacuum can in fact not be considered to be truly void. Quantum Mechanics, as the most accurate mathematical framework which can be employed in order to describe and predict the natural phenomena occurring at the atom-size dimensions of reality, may thus be considered as the root from which the concept of Quale Mechanics is emerged in order to construct the parallel between the metaphysical existence and the quantum physical wavefunction collapse. It is concluded that, within its underlying, Quantum Mechanics is a (hopefully fruitful) reiteration of the Ancient Greek Weltanschauung.Термін "Quale Механіка" запропоновано тут для опису якісних аспектів Квантової Механіки, які піддаються метафізичному розгляду. Мета Quale Механіки полягає в тому, щоб упорядкувати квантовий дискурс до його основних засад, щоб побудувати його власний – філософського характеру – Quale дискурс. Рамки дискусії розпочинаються поверненням до платонівського підходу до способу сприйняття/обробки знань, а потім обговорюються чотири стадії до досягнення поняття ейдосів. Природа відчуттєво-надвідчуттєвої дихотомії викривається шляхом протиставлення айстета ейдосу. Далі йде обговорення історичного розвитку та основ Квантової Механіки. Це включає розв'язання проблеми чорного тіла Планком з введенням квантів – у конфлікті з Ньютонівською фізикою, а потім поясненням Ейнштейном фотоефекту та наслідками, пов'язаними з подвійною природою світла (частинка проти хвилі) і двома узагальненнями квантового характеру речовини: планетарна модель атома Бора та подвійна частинково-хвильова природа електрона, продемонстрована де Бройлем. Подальше упорядкування цих напівкласичних концепцій в більш абстрактні математичні концепції Гайзенбергом, Борном, Діраком і Паулі потім розглядаються з принципом невизначеності Гайзенберга та поняттям хвильової функції, які недвозначно відходять від класичної детермінованої картини матерії. Прикладом цих досягнень є ефект Казимира – з його наслідками для гравітації і демонстрацією того, що вакуум насправді не можна вважати повністю пустим. Квантова Механіка, як найточніша математична рамка, яку можна використовувати для опису та передбачення природних явищ, які відбуваються на атомних розмірах реальності, можна розглядати як корінь, з якого виникла концепція Quale Механіки для побудови паралелі між метафізичним існуванням і квантовим фізичним згортанням хвильової функції. Зроблено висновок, що, в основі своїй, квантова механіка є повторення Античного Грецького Світогляду

Importance of the iron–sulfur component and of the siroheme modification in the resting state of sulfite reductase

The active site of sulfite reductase (SiR) consists of an unusual siroheme–Fe4S4 assembly coupled via a cysteinate sulfur, and serves for multi-electron reduction reactions. Clear explanations have not been demonstrated for the reasons behind the choice of siroheme (vs. other types of heme) or for the single-atom coupling to an Fe4S4 center (as opposed to simple adjacency or to coupling via chains consisting of more than one atom). Possible explanations for these choices have previously been invoked, relating to the control of the spin state of the substrate-binding (siro)heme iron, modulation of the trans effect of the (Fe4S4–bound) cysteinate, or modulation of the redox potential. Reported here is a density functional theory (DFT) investigation of the structural interplay (in terms of geometry, molecular orbitals and magnetic interactions) between the siroheme and the Fe4S4 center as well as the importance of the covalent modifications within siroheme compared to the more common heme b, aiming to verify the role of the siroheme modification and of the Fe4S4 cluster at the SiR active site, with focus on previously-formulated hypotheses (geometrical/sterics, spin state, redox and electron-transfer control). A calibration of various DFT methods/variants for the correct description of ground state spin multiplicity is performed using a set of problematic cases of bioinorganic Fe centers; out of 11 functionals tested, M06-L and B3LYP offer the best results – though none of them correctly predict the spin state for all test cases. Upon examination of the relative energies of spin states, reduction potentials, energy decomposition (electrostatic, exchange-repulsion, orbital relaxation, correlation and dispersion interactions) and Mayer bond indices in SiR models, the following main roles of the siroheme and cubane are identified: (1) the cubane cofactor decreases the reduction potential of the siroheme and stabilizes the siroheme–cysteine bond interaction, and (2) the siroheme removes the quasi-degeneracy between the intermediate and high-spin states found in ferrous systems by preserving the latter as ground state; the higher-spin preference and the increased accessibility of multiple spin states are likely to be important in selective binding of the substrate and of the subsequent reaction intermediates, and in efficient changes in redox states throughout the catalytic cycle

Why does sulfite reductase employ siroheme?

Sulfite reductase (SiR) contains in the active site a unique assembly of siroheme and a [4Fe4S] cluster, linked by a cysteine residue. Siroheme is a doubly reduced variant of heme that is not used for a catalytic function in any other enzyme. We have used non-equilibrium Green's function methods coupled with density functional theory computations to explain why SiR employs siroheme rather than heme. The results show that direct, through vacuum, charge-transfer routes are inhibited when heme is replaced by siroheme. This ensures more efficient channelling of the electrons to the catalytic iron during the six-electron reduction of sulfite to sulfide, limiting potential side-reactions that could occur if the incoming electrons were delocalized onto the macrocyclic ring

On the Origin of the Blue Color in The Iodine/Iodide/Starch Supramolecular Complex

The nature of the blue color in the iodine-starch reaction is still a matter of debate. Some textbooks still invoke charge-transfer bands within a chain of neutral I2 molecules inside the hydrophobic channel defined by the interior of the amylose helical structure. However, the consensus is that the interior of the helix is not altogether hydrophobic—and that a mixture of I2 molecules and iodide anions reside there and are responsible for the intense charge-transfer bands that yield the blue color of the “iodine-starch complex”. Indeed, iodide is a prerequisite of the reaction. However, some debate still exists regarding the nature of the iodine-iodine units inside the amylose helix. Species such as I3-, I5-, I7- etc. have been invoked. Here, we report UV-vis titration data and computational simulations using density functional theory (DFT) for the iodine/iodide chains as well as semiempirical (AM1, PM3) calculations of the amylose-iodine/iodide complexes, that (1) confirm that iodide is a pre-requisite for blue color formation in the iodine-starch system, (2) propose the nature of the complex to involve alternating sets of I2 and Ix- units, and (3) identify the nature of the charge-transfer bands as involving transfer from the Ix- σ* orbitals (HOMO) to I2 σ* LUMO orbitals. The best candidate for the “blue complex”, based on DFT geometry optimizations and TD-DFT spectral simulations, is an I2-I5-I2 unit, which is expected to occur in a repetitive manner inside the amylose helix