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| Registros recuperados: 14 | |
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| Raji Heyrovska; Lakshmi Atchison; Sara Narayan. |
| Nanomaterials are currently of great importance in science, technology and commercial applications. Since these materials are atomic layer thick and are a few square nanometers of area, a knowledge of their precise atomic structures will help in the exact understanding of the properties at the nanoscale and in the fabrication and design of the nanomaterials for their many uses. Their known inter-atomic distances have been used here to obtain the exact atomic radii of the component atoms and thereby their precise atomic structures, for the first time. Considered here are three nanomaterials with hexagonal structures, but of quite different properties, namely, graphene (an electrical conductor), boron nitride (an insulator) and coronene (indicators of life... |
| Tipo: Poster |
Palavras-chave: Chemistry. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/4357/version/1 |
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| Raji Heyrovska; Sara Narayan. |
| The authors have shown in recent years that interatomic and interionic distances are sums of the radii of the adjacent atoms and/or ions. Many examples will be provided and it will be shown how the experimental bond lengths agree with the radii sums. The examples include inorganic compounds like alkali halides, metal hydrides, graphene, etc., organic like aliphatic and aromatic compounds and biochemical like nucleic acids, amino acids, caffeine-related compounds and vitamins. |
| Tipo: Poster |
Palavras-chave: Chemistry. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/3292/version/1 |
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| Raji Heyrovska. |
| The Golden ratio which appears in the geometry of a variety of creations in Nature is found to arise right in the Bohr radius of the hydrogen atom due to the opposite charges of the electron and proton. The bond length of the hydrogen molecule is the diagonal of a square on the Bohr radius and hence also has two Golden sections, which form the cationic and anionic radii of hydrogen. It is shown here that these radii account quantitatively for the bond lengths of many hydrides when added to the atomic and Golden ratio based ionic radii of many other atoms. |
| Tipo: Manuscript |
Palavras-chave: Chemistry. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/2929/version/1 |
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| Raji Heyrovska; Saraswathi Narayan; Lakshmi Atchison. |
| This work celebrates the “International Year of Chemistry – 2011”, by providing “for the first time”, the structures at the atomic level of two important molecules, namely, ascorbic acid and aspirin. Ascorbic acid, also known as vitamin C, was discovered as a cure for scurvy which claimed many human lives and hence got its name. It is also supposed to be an antioxidant and to prevent flu. Aspirin is synthesized from salicylic acid and is widely used as a remedy for flu and has other medical uses such as saving the lives of cardiac patients as an anticoagulant of blood. The biochemistry and chemistry of both these compounds have been evolving for nearly a century ever since their discoveries. Here, the... |
| Tipo: Poster |
Palavras-chave: Chemistry; Developmental Biology; Bioinformatics. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/5966/version/1 |
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| Raji Heyrovska. |
| The author shows that Arrhenius's theory of partial electrolytic dissociation was immaturely displaced about eight decades ago by the empirical concept of ionic activities and the assumption of complete dissociation of electrolytes at all concentrations. The latter brought the theory of electrolytes over the next decades into a complicated state without any physical significance. Therefore, the author started a systematic investigation of the available data and could completely restore the original theory of partial dissociation. Now solution properties can be easily understood and quantitatively explained in terms of absolute concentrations and volumes of ions and ion pairs and hydration. |
| Tipo: Manuscript |
Palavras-chave: Chemistry. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6416/version/2 |
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| Raji Heyrovska. |
| The author has found in recent years that bond lengths are exact sums of the radii of adjacent atoms and or ions, where the ions have Golden ratio based radii. This work was prompted by the exciting observation last year of the Golden ratio in the magnetic properties of cobalt niobate. It is shown here that in cobalt and zinc niobates, cobalt, zinc and oxygen ions have Golden ratio based ionic radii, whereas in lead niobate, all atoms have covalent radii. Also, the angles at the single bond oxygen anion and atom are close to 1080, as in a pentagon. |
| Tipo: Manuscript |
Palavras-chave: Chemistry. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6059/version/1 |
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| Raji Heyrovska. |
| Conventional neutron numbers are based on the approximations that the mass of the electron is zero and that those of the proton and neutron are each equal to unity. It was shown, by using the exact rest masses, that the neutron numbers are actually one or two less than the conventional ones for atomic masses greater than 108. Presented here are new equations for the atomic mass, mass per nucleon and mass defects for the most abundant stable isotope (or the one with the longest half life) of each of the 118 elements of the Periodic Table. |
| Tipo: Manuscript |
Palavras-chave: Chemistry. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/4547/version/1 |
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| Raji Heyrovska. |
| Aqueous standard redox potentials are conventionally referred to that of the standard hydrogen electrode (SHE) as zero (IUPAC definition), in the absence of the knowledge of its absolute value. Recently, the author obtained its value (4.20 V) from a newly found linear dependence of redox potentials on ionization potentials. This has enabled now to express the potentials of standard reference electrodes in terms of the absolute values. |
| Tipo: Presentation |
Palavras-chave: Chemistry. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/4354/version/1 |
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| Raji Heyrovska. |
| The three positron based chemical entities, analogous to hydrogen atom, hydrogen molecule and hydride, are drawing increasing attention in the literature. While a lot is known about the binding energies, not much is known about the radii of the atoms and ions and bond lengths and structures of these exotic entities. This article brings for the first time exact values of these structural properties which are comparable with known data. It is hoped that the results will be of help for a better understanding and further development of the chemistry and physics of these exotic compounds and of their possible role as intermediates in chemical and interfacial processes. |
| Tipo: Manuscript |
Palavras-chave: Chemistry. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6290/version/1 |
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| Raji Heyrovska. |
| Structures of molecules are usually represented by arbitrary line drawings, ball and stick or space filling models. In recent years, the author found that using the appropriate radii of atoms and ions, bond lengths in inorganic, organic and biomolecules and of hydrogen bonds are exact sums of the radii of the adjacent atoms and or ions. This additivity of atomic radii was shown to hold also for the bond lengths in the twenty essential amino acids. On this basis, the atomic structures of the very important molecules mentioned in the title, have been presented here for the first time. It is hoped that these precise structures and their dimensions will shed new light into their role in biochemistry, pharmaceutical chemistry, environmental chemistry,... |
| Tipo: Manuscript |
Palavras-chave: Chemistry. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6692/version/1 |
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| Raji Heyrovska. |
| The author shows that Arrhenius's theory of partial electrolytic dissociation was immaturely displaced about eight decades ago by the empirical concept of ionic activities and the assumption of complete dissociation of electrolytes at all concentrations. The latter brought the theory of electrolytes over the next decades into a complicated state without any physical significance. Therefore, the author started a systematic investigation of the available data and could completely restore the original theory of partial dissociation. Now solution properties can be easily understood and quantitatively explained in terms of absolute concentrations and volumes of ions and ion pairs and hydration. |
| Tipo: Manuscript |
Palavras-chave: Chemistry. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6416/version/1 |
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| Raji Heyrovska. |
| The author has found in recent years that bond lengths are exact sums of the radii of adjacent atoms and or ions, where the ions have Golden ratio based radii. This work was prompted by the exciting observation last year of the Golden ratio in the magnetic properties of cobalt niobate. It is shown here that in cobalt and zinc niobates, cobalt, zinc and oxygen ions have Golden ratio based ionic radii, whereas in lead niobate, all atoms have covalent radii. Also, the angles at the single bond oxygen anion and atom are close to 1080, as in a pentagon. |
| Tipo: Manuscript |
Palavras-chave: Chemistry. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6059/version/2 |
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| Raji Heyrovska. |
| Cisplatin is cis-diamminedichloroplatinum (II) of chemical formula, Pt(NH3)Cl2, abbreviated as cis-DDP and known commercially as platinol. It is used widely as an anticancer drug for various types of cancer, ever since its discovery two centuries ago and has become a target of extensive researches. Transplatin, trans-DDP on the other hand, is found to be less or ineffective to treat cancers. Cisplatin is known to interact mainly with the N(7) nitrogen of guanine in nucleic acids, after a water molecule takes away one of the chlorines by hydrolysis. This initiates the damage of nucleic acids and eventually leads to apoptosis. However the way how this happens and why transplatin is less effective is not completely clear. Here the author brings some new... |
| Tipo: Manuscript |
Palavras-chave: Cancer; Chemistry; Molecular Cell Biology; Pharmacology. |
| Ano: 2012 |
URL: http://precedings.nature.com/documents/6891/version/1 |
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| Registros recuperados: 14 | |
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