Lowest Energy Form Research Articles

Experimental and Computational Study of the Gas-Phase Acidities of Acidic Di- and Tripeptides.

Gas-phase acidities (GA or Δ Gacid) of acidic di- and tripeptides are determined for the first time. The peptides studied are composed of inert alanine (A) residues and one X residue of either aspartic acid (D) or glutamic acid (E): AX, XA, AAX, AXA, and XAA. Experimental GAs were measured by the thermokinetic method of deprotonation ion/molecule reactions in a Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by composite correlated molecular orbital theory at the G3(MP2) level for deprotonation of carboxylic acid groups both at the C-terminus and at the side chain. Excellent agreement was found between experimental and calculated GA values. There is a slight preference for peptides with D being more acidic than analogous peptides with E, which agrees with the GAs of the corresponding amino acids. Experiments showed that peptides are more acidic (lower numerical GA values) when the acidic residue is located at the C-terminus (i.e., AX or AAX). The lowest energy form of deprotonated AAE has a unique structure where the longer side chain of E allows the two carboxylates, which are in close proximity, to share the proton. The tripeptides are less acidic (higher GA value) by 3-7 kcal/mol when the acidic residue is in the center. The tripeptides are more acidic (by 2-10 kcal/mol) than dipeptides containing the same acidic residue at the same location.

A Computational Determination of the Origins of Diastereoselective Alkylations of a Cysteinesulfenate Anion

Sulfenic acid anions (RSO–) represent an untapped functional group for the formation of sulfoxides and other organic compounds. Their stereoselective alkylation is an important component of this chemistry, but factors governing reaction outcomes are not fully understood. The current study uses Density Functional Theory methods to break down the influencing roles of substituents attached to 2‐aminoethanesulfenate. The lithium counterion can be coordinated to pendant ester or carbamate carbonyl groups, whereas the sulfenate oxygen readily participates in hydrogen bonding with proximal hydrogen atoms of the (protected) amino group. A Moc‐protected, ester substituted, 2‐aminoethanesulfenate adopts both lithium coordination and hydrogen bonding in the lowest energy form and demonstrates stereoselective methylation and benzylation consistent with experiments from the literature.

Ultradense Hydrogen H(0) as Stable Dark Matter in the Universe: Extended Red Emission Spectra Agree with Rotational Transitions in H(0)

Abstract Studies of ultradense hydrogen H(0) in our laboratory have been reported in around 50 publications. The proton solar wind was shown to agree well with the protons ejected by Coulomb explosions in p(0). H(0) is a quantum material and can have at least two slightly different forms—ultradense protium p(0) and ultradense deuterium D(0)—which are stable even inside many stars. Mixed phases pD(0) have also been studied. These phases are the lowest-energy forms of hydrogen, and H(0) will probably exist everywhere where hydrogen exists in the universe. Rotational spectra from H(0) have been studied in laboratory experiments in emission in the visible range, giving good agreement with observations of ERE (extended red emission) in space. The ERE bands and sharp peaks agree with rotational transitions for a few coupled p–p and p–D pairs in the well studied spin state s = 4 in H(0). Since ERE is observed almost everywhere in space, this proves that H(0) is common in space. The rotational absorption from the ground state in p(0) agrees with the 220 nm extinction bump for three coupled p–p pairs in the most common spin state s = 2 studied. The uneven distribution of deuterium in space may be due to the slightly different properties of D(0), which separate it from p(0). The dark “missing mass” concluded to exist in the halos of rotating galaxies is proposed as being due to accumulation of H(0) there. Other important implications of the superfluid and superconductive phase H(0) in space await discovery.

UV-induced transformations of matrix-isolated 6-azacytosine

UV-induced transformations were studied for monomers of 6-azacytosine isolated in low-temperature Ar matrices. In contrast to cytosine, where the amino-hydroxy (AH) tautomer is the lowest-energy form, the amino-oxo (AO) and imino-oxo (IO) isomers of 6-azacytosine were found to be the most stable and most populated. Due to the high relative energy of the AH tautomer of 6-azacytosine, this form is not populated in low-temperature matrices after their formation and prior to any irradiation. Excitation of 6-azacytosine monomers with UV light from the 328-300 nm range led to structural transformations of AO and IO forms. The initially most populated AO tautomer was observed either to convert, in a phototautomeric reaction, into the AH product or to undergo photodecarbonylation to yield 4-amino-1,2,3-(2H)-triazole. The relative efficiencies of the two processes depend on the wavelength and on the pulsed or continuous-wave character of the UV light used for excitation. For the IO tautomer of 6-azacytosine, the excitation with UV 328-300 nm light induced the photoconversion of the initially more populated anti IO1 isomer into the syn IO2 form. This transformation was found to be partially photoreversible.

Calcite–magnesite solid solutions: using genetic algorithms to understand non-ideality

We show how a genetic algorithm (GA) generates efficiently the energy landscape of the equimolar calcite–magnesite (CaCO3—MgCO3) solid solution. Starting from a random configuration of cations and a supercell containing 480 atoms, the lowest energy form of ordered dolomite was found in all runs, in 94% of which it was located with less than 20,000 fitness evaluations. Practical implementation and operation of the GA are discussed in detail. The method can also generate both low-lying and high-lying excited states. Detailed analysis of the energy-minimised structures of the different configurations reveals that low energies are associated with reduction of strain associated with rotation of the carbonate groups, a mechanism possible only when a carbonate layer lies between a layer of just Ca and a layer of just Mg. Such strain relief is not possible in the equimolar MgO–CaO solid solution despite the similarity of the crystal structures of these binary oxides to calcite–magnesite, and therefore, the enthalpy of mixing is very high. Implications for thermodynamic configurational averaging over the minima in the energy landscape are briefly considered. Overall, the genetic algorithm is shown to be a powerful tool in probing non-ideality in solid solutions and revealing the ordering patterns that give rise to such behaviour.

(E)-2-{[(2-Amino-phen-yl)imino]-meth-yl}-5-(benz-yl-oxy)phenol and (Z)-3-benz-yl-oxy-6-{[(5-chloro-2-hy-droxy-phen-yl)amino]-methyl-idene}cyclo-hexa-2,4-dien-1-one.

The title Schiff base compounds, C20H18N2O2 (I) and C20H16ClNO3 (II), were synthesized from 4-benz-yloxy-2-hy-droxy-benzaldehyde by reaction with 1,2-di-amino-benzene for (I), and condensation with 2-amino-4-chloro-phenol for (II). Compound (I) adopts the enol-imine tautomeric form with an E configuration about the C=N imine bond. In contrast, the o-hy-droxy Schiff base (II), is in the keto-imine tautomeric form with a Z configuration about the CH-NH bond. Neither mol-ecule is planar. In (I), the central benzene ring makes dihedral angles of 46.80 (10) and 78.19 (10)° with the outer phenyl-amine and phenyl rings, respectively, while for (II), the corresponding angles are 5.11 (9) and 58.42 (11)°, respectively. The mol-ecular structures of both compounds are affected by the formation of intra-molecular contacts, an O-H⋯N hydrogen bond for (I) and an N-H⋯O hydrogen bond for (II); each contact generates an S(6) ring motif. In the crystal of (I), strong N-H⋯O hydrogen bonds form zigzag chains of mol-ecules along the b-axis direction. Mol-ecules are further linked by C-H⋯π inter-actions and offset π-π contacts and these combine to form a three-dimensional network. The density functional theory (DFT) optimized structure of compound (II), at the B3LYP/6-311+G(d) level, confirmed that the keto tautomeric form of the compound, as found in the structure determination, is the lowest energy form. The anti-oxidant capacities of both compounds were determined by the cupric reducing anti-oxidant capacity (CUPRAC) process.

Conformational analysis of macrocyclic frankincense (Boswellia) diterpenoids.

Frankincense oleoresin has been used in traditional medicine for more than 5000years. The phytochemistry of frankincense (Boswellia spp.) resins includes triterpenoids (including boswellic acids and their derivatives), diterpenoids (cembrenoids and cneorubenoids), and essential oils. The macrocyclic cembrene diterpenoids may play a part in the biological activities of frankincense resin, but neither the biological targets nor the modes of interaction with the targets are currently known. How these macrocycles interact with biological macromolecules likely depends on what conformation(s) are energetically available to them. In this work, a conformational analysis of 15 Boswellia cembrene diterpenoids and 1 verticillane diterpenoid was carried out at the B3LYP/6-31G* and M06-2X/6-31G* levels of theory, including the SM8 aqueous solvation model. The lowest-energy conformations of boscartin B and incensole oxide were the same as the previously reported X-ray crystal structures, while the lowest-energy conformations of boscartins A and C were very similar to the crystal structures. Boscartins D-H and isoincensole oxide showed only one low-energy conformation for each compound and are predicted to be conformationally locked. Incensole, isoincensolol, and serratol are predicted to be conformationally mobile with several low-energy forms. The conformational mobility of Boswellia cembrenoid diterpenoids depends largely on the degree of epoxidation, either oxirane or tetrahydrofuran rings.

The centers of premeltons signal the beginning and ends of genes

Premeltons are examples of emergent structures (i.e., structural solitons) that arise spontaneously in DNA due to the presence of nonlinear excitations in its structure. They are of two kinds: B-B (or A-A) premeltons form at specific DNA-regions to nucleate site-specific DNA melting. These are stationary and, being globally nontopological, undergo breather motions that allow drugs and dyes to intercalate into DNA. B-A (or A-B) premeltons, on the other hand, are mobile, and being globally topological, act as phaseboundaries transforming B- into A-DNA during the structural phase-transition. They are not expected to undergo breather-motions. A key feature of both types of premeltons is the presence of an intermediate structural-form in their central regions (proposed as being a transition-state intermediate in DNA-melting and in the B- to A-transition), which differs from either A- or B-DNA. called Beta- DNA, this is both metastable and hyperflexible and contains an alternating sugar-puckering pattern along the polymer-backbone combined with the partial-unstacking (in its lower energy-forms) of every other base pair. Beta-DNA is connected to either B- or to A-DNA on either side by boundaries possessing a gradation of nonlinear structural-change, these being called the kink and the anti-kink regions. The presence of premeltons in DNA leads to a unifying theory to understand much of DNA physical-chemistry and molecular-biology. In particular, premeltons are predicted to define the 5??? and 3??? ends of genes in naked-DNA and DNA in active chromatin, this having important implications for understanding physical aspects of the initiation, elongation and termination of RNA-synthesis during transcription. For these and other reasons, the model will be of broader interest to the general audience working in these areas. The model explains a wide variety of data, and carries within it a number of experimental predictions all readily testable as will be described in the presentation. Recent Publications 1. Sobell H M (2016) Premeltons in DNA. Journal of Structural and Functional Genomics 17(1):17-31. 2. Sobell H M (2009) Premeltons in DNA. A Unifying Polymer Physics Concept to Understand DNA Physical Chemistry and Molecular-Biology. Explanatory Publications ISBN-978-0-615-33828-6. 3. Sobell H M (2013) Organization of DNA in Chromatin. Rather than bending uniformly along its length, nucleosomal DNA is proposed to consist of multiple segments of B- and A- DNA held together by kinks when forming its left-handed toroidal superhelical structure. Explanatory Publications ISBN-978-0-692-01974-0

The centers of premeltons signal the beginning and ends of genes

Premeltons are examples of emergent structures (i.e., structural solitons) that arise spontaneously in DNA due to the presence of nonlinear excitations in its structure. They are of two kinds: B-B (or A-A) premeltons form at specific DNA-regions to nucleate site-specific DNA melting. These are stationary and, being globally nontopological, undergo breather motions that allow drugs and dyes to intercalate into DNA. B-A (or A-B) premeltons, on the other hand, are mobile, and being globally topological, act as phaseboundaries transforming B- into A-DNA during the structural phase-transition. They are not expected to undergo breather-motions. A key feature of both types of premeltons is the presence of an intermediate structural-form in their central regions (proposed as being a transition-state intermediate in DNA-melting and in the B- to A-transition), which differs from either A- or B-DNA. called Beta- DNA, this is both metastable and hyperflexible and contains an alternating sugar-puckering pattern along the polymer-backbone combined with the partial-unstacking (in its lower energy-forms) of every other base pair. Beta-DNA is connected to either B- or to A-DNA on either side by boundaries possessing a gradation of nonlinear structural-change, these being called the kink and the anti-kink regions. The presence of premeltons in DNA leads to a unifying theory to understand much of DNA physical-chemistry and molecular-biology. In particular, premeltons are predicted to define the 5??? and 3??? ends of genes in naked-DNA and DNA in active chromatin, this having important implications for understanding physical aspects of the initiation, elongation and termination of RNA-synthesis during transcription. For these and other reasons, the model will be of broader interest to the general audience working in these areas. The model explains a wide variety of data, and carries within it a number of experimental predictions all readily testable as will be described in the presentation. Recent Publications 1. Sobell H M (2016) Premeltons in DNA. Journal of Structural and Functional Genomics 17(1):17-31. 2. Sobell H M (2009) Premeltons in DNA. A Unifying Polymer Physics Concept to Understand DNA Physical Chemistry and Molecular-Biology. Explanatory Publications ISBN-978-0-615-33828-6. 3. Sobell H M (2013) Organization of DNA in Chromatin. Rather than bending uniformly along its length, nucleosomal DNA is proposed to consist of multiple segments of B- and A- DNA held together by kinks when forming its left-handed toroidal superhelical structure. Explanatory Publications ISBN-978-0-692-01974-0

Adventures in boron chemistry - the prediction of novel ultra-flexible boron oxide frameworks.

Recent periodic density functional calculations have predicted the existence of ultra-flexible low-energy forms of boron oxides in which rigid boron-oxygen heterocycles are linked by flexible B-O-B bridges. The minima in the energy landscapes of these frameworks are remarkably broad, with widths in excess of those of many hybrid metal-organic frameworks. Enormous changes in cell volume, which can exceed a factor of two, are accompanied by negligible changes in energy. Here we explore the underlying reasons for this behaviour using molecular electronic-structure calculations, periodic density functional theory and template-based geometric simulations. The angular flexibility of the B-O-B bridge depends only upon the geometry of the local B2O5 unit, independent of the configuration of neighbouring bridges. Unique cooperativity between the bending and twisting motions of the bridges leads to considerable anisotropy in framework flexibility. Exceptional flexibility is conferred not only by the intrinsic bending flexibility of the bridges but by topological factors, crucially the relaxation of torsional constraints when B3O3 rings are present. We test these conclusions by showing how the flexibility of the frameworks can be tuned by decoration with isoelectronic rings. The new nanoporous boron oxides presented in this work are predicted to be potential novel guest-host materials because of their flat energy landscapes. Furthermore, such structures can be generated systematically from silicates by the substitution of B2O54- for SiO44-. A borate analogue of β-cristobalite is shown to be isoenergetic with the known B2O3-I polymorph. We raise the possibility of new families of frameworks and zeolite analogues.

On the photochemistry of Fe2(edt)(CO)4(PMe3)2, a [FeFe]‐hydrogenase model: A DFT/TDDFT investigation

AbstractThe photochemistry of the [FeFe] hydrogenases model [Fe2(edt)(CO)4(PMe3)2] (edt = 1‐2 ethane‐dithiolate, (1) is investigated at Time‐Dependent Density Functional Theory (TDDFT) level, focusing on the effect of the phosphine ligands on the early stages of the photodynamic of the system compared to that of the all CO model Fe2(pdt)(CO)6 (2) (pdt = 1‐3 propanedithiolate). We observed a role of the Fe→S charge transfer for the lower energy singlet transitions, unveiling a photoisomerization pathway between the lowest energy forms while the higher energy excitations are likely involved in the CO dissociation pathways. TDDFT shows that the average Fe‐CO bond elongation in 1 is shorter than that observed in 2, providing the electronic structure rationale on the observation that diiron dithiolates are more photo‐stable with respect to the CO photolysis than the all CO model. This is relevant for catalyst photo‐stability and is an advantageous and thus desirable feature for practical applications of photo‐hydrogen evolution.

On the singularities of the Szegő projections on lower energy forms

Let $X$ be an abstract not necessarily compact orientable CR manifold of dimension $2n-1$, $n\geqslant2$. Let $\Box^{(q)}_{b}$ be the Gaffney extension of Kohn Laplacian for $(0,q)$-forms. We show that the spectral function of $\Box^{(q)}_b$ admits a full asymptotic expansion on the non-degenerate part of the Levi form. As a corollary, we deduce that if $X$ is compact and the Levi form is non-degenerate of constant signature on $X$, then the spectrum of $\Box^{(q)}_b$ in $]0,\infty[$ consists of point eigenvalues of finite multiplicity. Moreover, we show that a certain microlocal conjugation of the associated Szeg\"o kernel admits an asymptotic expansion under a local closed range condition. As applications, we establish the Szeg\"o kernel asymptotic expansions on some weakly pseudoconvex CR manifolds and on CR manifolds with transversal CR $S^1$ actions. By using these asymptotics, we establish some local embedding theorems on CR manifolds and we give an analytic proof of a theorem of Lempert asserting that a compact strictly pseudoconvex CR manifold of dimension three with a transversal CR $S^1$ action can be CR embedded into $\mathbb{C}^N$, for some $N\in\mathbb N$.

Functional doping of acrylic PMMA with photochromic dyes

Work from Poland has studied the thermodynamic and kinetic stability of PMMA when doped with a photochromic dye molecule. Visible light absorption is induced in fabricated photochromic PMMA fibres for optoelectronic device applications. PMMA fibres doped in local regions with Bis-MSB under UV irradiation. Molecular switches are molecules that display a binary response when exposed to specific conditions or stimuli. A common example of this is a structural change in molecular switch materials when exposed to UV radiation. This means that meta-stable, higher-energy structural orientations of a molecule can appear under UV irradiation. A switching phenomenon between low- and high-energy geometries is often fully reversible making these systems suitable for use in several applications including optical switches, attenuators, holograms, optical memory, and smart textiles. The chemical structure of Photochromic Bis-MSB incorporated into PMMA fibres. PMMA, poly(methyl methacrylate), is a transparent thermoplastic material that is versatile, strong and recyclable. PMMA optical fibres offer numerous benefits, including high flexibility and numerical aperture, low production cost, and good biocompatibility. A current limitation of PMMA fibres compared to optically active silica fibres is relatively high optical absorption in the visible and near infrared region of the electromagnetic spectrum. The incorporation of photosensitive dyes introduces additional absorption bands and increases the frequencies of light that are absorbed by the material. A common photochromic dye, 1,4-bis(2-methylstyryl)benzene (Bis-MSB), displays high transmittance in the visible region of the electromagnetic spectrum. Bis-MSB also behaves as a molecular switch when exposed to light, where its geometry is changed from linear (cis) to bent (trans) configurations following bond rotation. Thus, incorporating Bis-MSB into PMMA creates a coloured material with controllable and reversible broad-range light absorption. Coloured photoresponsive materials that are transparent, such as Bis-MSB doped PMMA, are favourable polymer materials for organic electronics as they efficiently absorb light within a useful region of the electromagnetic spectrum. In this issue of Electronics Letters, Dr Piotr Miluski and colleagues at Bialystok University of Technology, Poland, fabricate Bis-MSB-doped PMMA and report the optical transmission properties and kinetic relaxation lifetimes of this unique material. Following fabrication of the Bis-MSB PMMA fibres, the samples were exposed to high-energy UV radiation with a 1 MW peak power at 355 nm laser. A colour change was immediately observed, which visibly demonstrates the molecular structural switch of Bis-MSB under UV radiation. A comparison of light transmission between the undoped fibres and the Bis-MSB-doped PMMA fibres is made in the paper. This comparison shows the frequency change of light absorption due to the presence of the dopant molecules and demonstrates that the dopant induces wideband visible light absorption between 400–670 nm. This range of wavelengths is of particular interest for solar cell applications. Thermal relaxation was shown to lead to the decolouration of the fabricated polymer fibres, which was further supported by measured relaxation times in an analysis of the kinetic properties of the system. Long relaxation times can be useful for UV indicators and optical memory systems. The “Main advantage of (Bis-MSB) doped PMMA is that it offers high transmittance of its lower energy form in the VIS spectrum range” said Miluski. The ability to harness and modulate the optical properties of a molecule and control its free-volume as it rotates from linear to bent is well demonstrated within this paper. The development of organic-based functional materials for optical fibre technology introduces some limitations, including organic breakdown at high temperatures, solvent evaporation and low thermal conductivity of polymers. Moreover, the dopant distribution and polymer host homogeneity have to be carefully controlled to ensure a continuous optical response throughout the material. Recent research developments in the field of smart organic materials offer new functional properties that do not suffer from the described disadvantages. Low-energy consumption of organic devices offers significant advantages over well-developed silicon-based electronics. In the field of photochromic polymers, one of the main challenges is the ability to modulate high-frequency optical properties. Dr Miluski predicts that photochromic PMMA fibres will be appropriate for use in real-time holograms and for optical radiation modulation in telecommunication applications. Ultra-stable cis/trans isomerisation is also strongly desired in the field of logical gates and optical memory, where the use of photo-responsive PMMA fibres could offer both lower power consumption and higher storage density.

Berezin–Toeplitz quantization for lower energy forms

ABSTRACTLet M be an arbitrary complex manifold and let L be a Hermitian holomorphic line bundle over M. We introduce the Berezin–Toeplitz quantization of the open set of M where the curvature on L is nondegenerate. In particular, we quantize any manifold admitting a positive line bundle. The quantum spaces are the spectral spaces corresponding to [0,k−N], where N>1 is fixed, of the Kodaira Laplace operator acting on forms with values in tensor powers Lk. We establish the asymptotic expansion of associated Toeplitz operators and their composition in the semiclassical limit k→∞ and we define the corresponding star-product. If the Kodaira Laplace operator has a certain spectral gap this method yields quantization by means of harmonic forms. As applications, we obtain the Berezin–Toeplitz quantization for semi-positive and big line bundles.

The electromagnetic Sigma-to-Lambda hyperon transition form factors at low energies

.Using dispersion theory the low-energy electromagnetic form factors for the transition of a Sigma to a Lambda hyperon are related to the pion vector form factor. The additionally required input, i.e. the two-pion-Sigma-Lambda amplitudes are determined from relativistic next-to-leading-order (NLO) baryon chiral perturbation theory including the baryons from the octet and optionally from the decuplet. Pion rescattering is again taken into account by dispersion theory. It turns out that the inclusion of decuplet baryons is not an option but a necessity to obtain reasonable results. The electric transition form factor remains very small in the whole low-energy region. The magnetic transition form factor depends strongly on one not very well determined low-energy constant of the NLO Lagrangian. One obtains reasonable predictive power if this low-energy constant is determined from a measurement of the magnetic transition radius. Such a measurement can be performed at the future Facility for Antiproton and Ion Research (FAIR).

Self-Terminating Confinement Approach for Large-Area Uniform Monolayer Graphene Directly over Si/SiOx by Chemical Vapor Deposition.

To synthesize graphene by chemical vapor deposition (CVD) both in large area and with uniform layer number directly over Si/SiOx has proven challenging. The use of catalytically active metal substrates, in particular Cu, has shown far greater success and therefore is popular. That said, for electronics applications it requires a transfer procedure, which tends to damage and contaminate the graphene. Thus, the direct fabrication of uniform graphene on Si/SiOx remains attractive. Here we show a facile confinement CVD approach in which we simply "sandwich" two Si wafers with their oxide faces in contact to form uniform monolayer graphene. A thorough examination of the material reveals it comprises faceted grains despite initially nucleating as round islands. Upon clustering, they facet to minimize their energy. This behavior leads to faceting in polygons, as the system aims to ideally form hexagons, the lowest energy form, much like the hexagonal cells in a beehive, which requires the minimum wax. This process also leads to a near minimal total grain boundary length per unit area. This fact, along with the high graphene quality, is reflected in its electrical performance, which is highly comparable with graphene formed over other substrates, including Cu. In addition, the graphene growth is self-terminating. Our CVD approach is easily scalable and will make graphene formation directly on Si wafers competitive against that from metal substrates, which suffer from transfer. Moreover, this CVD route should be applicable for the direct synthesis of other 2D materials and their van der Waals heterostructures.

The centers of premeltons signal the beginning and ends of genes

Premeltons are examples of emergent structures (i.e., structural solitons) that arise spontaneously in DNA due to the presence of nonlinear excitations in its structure. They are of two kinds: B-B (or A-A) premeltons form at specific DNA-regions to nucleate site-specific DNA melting. These are stationary and, being globally nontopological, undergo breather motions that allow drugs and dyes to intercalate into DNA. B-A (or A-B) premeltons, on the other hand, are mobile, and being globally topological, act as phaseboundaries transforming B- into A-DNA during the structural phase-transition. They are not expected to undergo breather-motions. A key feature of both types of premeltons is the presence of an intermediate structural-form in their central regions (proposed as being a transition-state intermediate in DNA-melting and in the B- to A-transition), which differs from either A- or B-DNA. called Beta- DNA, this is both metastable and hyperflexible and contains an alternating sugar-puckering pattern along the polymer-backbone combined with the partial-unstacking (in its lower energy-forms) of every other base pair. Beta-DNA is connected to either B- or to A-DNA on either side by boundaries possessing a gradation of nonlinear structural-change, these being called the kink and the anti-kink regions. The presence of premeltons in DNA leads to a unifying theory to understand much of DNA physical-chemistry and molecular-biology. In particular, premeltons are predicted to define the 5??? and 3??? ends of genes in naked-DNA and DNA in active chromatin, this having important implications for understanding physical aspects of the initiation, elongation and termination of RNA-synthesis during transcription. For these and other reasons, the model will be of broader interest to the general audience working in these areas. The model explains a wide variety of data, and carries within it a number of experimental predictions all readily testable as will be described in the presentation. Recent Publications 1. Sobell H M (2016) Premeltons in DNA. Journal of Structural and Functional Genomics 17(1):17-31. 2. Sobell H M (2009) Premeltons in DNA. A Unifying Polymer Physics Concept to Understand DNA Physical Chemistry and Molecular-Biology. Explanatory Publications ISBN-978-0-615-33828-6. 3. Sobell H M (2013) Organization of DNA in Chromatin. Rather than bending uniformly along its length, nucleosomal DNA is proposed to consist of multiple segments of B- and A- DNA held together by kinks when forming its left-handed toroidal superhelical structure. Explanatory Publications ISBN-978-0-692-01974-0

The Centers of Premeltons Signal the Beginning and Ends of Genes

Premeltons are examples of emergent structures (i.e., structural solitons) that arise spontaneously in DNA due to the presence of nonlinear excitations in its structure. They are of two kinds: B-B (or A-A) premeltons form at specific DNA-regions to nucleate site-specific DNA melting. These are stationary and, being globally nontopological, undergo breather motions that allow drugs and dyes to intercalate into DNA. B-A (or A-B) premeltons, on the other hand, are mobile, and being globally topological, act as phaseboundaries transforming B- into A-DNA during the structural phase-transition. They are not expected to undergo breather-motions. A key feature of both types of premeltons is the presence of an intermediate structural-form in their central regions (proposed as being a transition-state intermediate in DNA-melting and in the B- to A-transition), which differs from either A- or B-DNA. called Beta- DNA, this is both metastable and hyperflexible and contains an alternating sugar-puckering pattern along the polymer-backbone combined with the partial-unstacking (in its lower energy-forms) of every other base pair. Beta-DNA is connected to either B- or to A-DNA on either side by boundaries possessing a gradation of nonlinear structural-change, these being called the kink and the anti-kink regions. The presence of premeltons in DNA leads to a unifying theory to understand much of DNA physical-chemistry and molecular-biology. In particular, premeltons are predicted to define the 5??? and 3??? ends of genes in naked-DNA and DNA in active chromatin, this having important implications for understanding physical aspects of the initiation, elongation and termination of RNA-synthesis during transcription. For these and other reasons, the model will be of broader interest to the general audience working in these areas. The model explains a wide variety of data, and carries within it a number of experimental predictions all readily testable as will be described in the presentation. Recent Publications 1. Sobell H M (2016) Premeltons in DNA. Journal of Structural and Functional Genomics 17(1):17-31. 2. Sobell H M (2009) Premeltons in DNA. A Unifying Polymer Physics Concept to Understand DNA Physical Chemistry and Molecular-Biology. Explanatory Publications ISBN-978-0-615-33828-6. 3. Sobell H M (2013) Organization of DNA in Chromatin. Rather than bending uniformly along its length, nucleosomal DNA is proposed to consist of multiple segments of B- and A- DNA held together by kinks when forming its left-handed toroidal superhelical structure. Explanatory Publications ISBN-978-0-692-01974-0

What’s Law Got to Do with It? Crisis, Growth, Inequality and the Alternative Futures of Legal Thought

AbstractThe most striking economic and political fact of the past forty years has been the dramatic increase in economic and political inequality throughout the advanced economies. This Article considers this development as an occasion to explore the contribution of contemporary law and legal thought to the problem of inequality. I focus on two main themes: the naturalization of the present institutional form of the regulated market economy, and the naturalization of the present low-energy form of democracy. I argue that in each case, the absence of structural vision in law prevents us from understanding the sources of and remedies for inequality. We must rescue the insight from the compromise and begin to develop a better way of thinking about law and the economy, if we are to understand and address the rise of inequality. Therefore, three programmatic implications are suggested in this Article regarding three domains: politics, production and finance.

Parent, Unsubstituted Hemiporphycene: Synthesis and Properties.

Among seven possible nitrogen-in constitutional isomers of porphyrin only one, porphycene, has been obtained so far in the free, unsubstituted form. Herein, the synthesis of another isomer, parent hemiporphycene (HPc), and its thorough structural, spectral, photophysical, electrochemical, and theoretical characterization are reported. Most of the properties of HPc are intermediate between those of porphyrin and porphycene, as evidenced by the values of inner-cavity dimensions, orbital-energy splittings, absorption coefficients, magnetic circular dichroism parameters, NH-stretching frequencies, fluorescence quantum yields, tautomerization rates, and redox potentials. The largest differences arise with respect to tautomerism, due to the low symmetry of HPc and inequivalence of the four nitrogen atoms that define the inner cavity. Two trans tautomers are observed, separated in energy by about 1 kcal mol-1 . Tautomerization from the higher- to the lower-energy form is detected in the lowest-excited singlet state and occurs at a rate that is about four orders of magnitude lower than that observed for porphycene. Hemiporphycene is a very good model for the investigation of inequivalent intramolecular H-bonds present in one molecule; two such bonds in HPc reveal unusual characteristics, and the bond strength results from the interplay between the N⋅⋅⋅N distance and the N-H-N angle.