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Rhenium is a unique metal in the 5d-series of transition metals having the highest boiling point in the periodic table. It is also known to exist in poly-coordinated states with other rhenium atoms. Based on the existence of strikingly unusual states of elements in astrophysical bodies of nebulae, interstellar debris, exoplanets and other part of the universe, a set of ab initio calculations of the rhenium dimer has been conducted to provide detailed description of its molecular properties that are applicable to the astrochemical research. Ab initio calculations and NBO analysis revealed that rhenium forms quintuple bond in its diatomic state and that it displays preferred state of triplet configuration with high-lying electrons. Calculations also revealed that the two states of rhenium dimer vary in their bonding nature. The singlet spin space is composed of five single bonds, while the triplet state comprises four bonds and two additional lone pairs. Interestingly, while these two states vary in subdivision of electrons at the highest d-level, they share the same frequencies while having different zero-point energies. The calculations reveal intrinsic synergy between the atoms composed of natural bond orbitals, the bonding pattern and the thermochemical properties of Re2, all features being of significant importance to physical and chemical sciences. © 2016 Springer Science+Business Media New York Source

Manzetti S.,Fjordforsk AS | Manzetti S.,Uppsala University | Vasilache D.,National Institute for Research and Development in Microtechnologies | Francesco E.,National Research Council Italy
Advances in Manufacturing | Year: 2015

Bionanosensors and nanosensors have been devised in recent years with the use of various materials including carbon-based nanomaterials, for applications in diagnostics, environmental science and microelectronics. Carbon-based materials are critical for sensing applications, as they have physical and electronic properties which facilitate the detection of substances in solutions, gaseous compounds and pollutants through their conductive properties and resonance-frequency transmission capacities. In this review, a series of recent studies of carbon nanotubes (CNTs) based nanosensors and optical systems are reported, with emphasis on biochemical, chemical and environmental detection. This study also encompasses a background and description of the various properties of the nanomaterials, and the operation mechanism of the manufactured nanosensors. The use of computational chemistry is applied in describing the electronic properties and molecular events of the included nanomaterials during operation. This review shows that resonance-based sensing technologies reach detection limits for gases, such as ammonia down to 10−24 level. The study also shows that the properties of the carbon nanomaterials give them unique features that are critical for designing new sensors based on electrocatalysis and other reactive detection mechanisms. Several research fields can benefit from the described emerging technologies, such as areas of research in environmental monitoring, rapid-on site diagnostics, in situ analyses, and blood and urine sampling in medical and sport industry. Carbon nanomaterials are critical for the operational sensitivity of nanosensors. Considering the low cost of fabrication, carbon nanomaterials can represent an essential step in the manufacturing of tomorrow’s commercial sensors. © 2015, Shanghai University and Springer-Verlag Berlin Heidelberg. Source

Manzetti S.,Uppsala University | Manzetti S.,Fjordforsk AS | Van Der Spoel E.R.,Uppsala University | Van Der Spoel D.,Uppsala University
Chemical Research in Toxicology | Year: 2014

Industrialism has brought a long series of benefits for modern civilization. Concomitantly, reversible and irreversible changes have been inflicted upon the environment, affecting humans, animals, and whole ecosystems and leading to effects such as declining reproduction in modern human beings, developmental challenges on various species, and destroyed habitats and ecosystems across the globe. In this context, a vast repertoire of modern and older literature is reviewed for a series of pollutants and their status as of 2014. The compound classes covered in this review are polychlorinated biphenyls, halogenated hydrocarbons, estrogen analogues, phthalates, dioxins, perfluorinated compounds, and brominated flame retardants. These groups represent ubiquitous pollutants, of which some have circulated in the environment for more than 60 years. In this context, this review describes the chemical properties, the environmental fate, and the toxicological effects of these classes of pollutants on humans and animals, including an introductory section on the detoxification systems that are triggered in most species upon intoxication. This combined review of in vivo transformation, chemistry, toxicological properties, and structure-activity relationships of pollutants aids in the understanding of the fate, biomagnification, bioaccumulation, and transformation of these compounds, which is essential for toxicologists, environmental scientists, and environmental legislators. The review is concluded with an outlook. © 2014 American Chemical Society. Source

Manzetti S.,Uppsala University | Manzetti S.,Fjordforsk AS | Zhang J.,Uppsala University | Zhang J.,Zhejiang University | Van Der Spoel D.,Uppsala University
Biochemistry | Year: 2014

Vitamins are crucial components in the diet of animals and many other living organisms. One of these essential nutrients, thiamin, is known to be involved in several cell functions, including energy metabolism and the degradation of sugars and carbon skeletons. Other roles that are connected to this vitamin are neuronal communication, immune system activation, signaling and maintenance processes in cells and tissues, and cell-membrane dynamics. Because of the key functions of thiamin, uptake and transport through the body are crucial. Its uptake route is relatively complex, encompassing a variety of protein families, including the solute carrier anion transporters, the alkaline phosphatase transport system, and the human extraneuronal monoamine transporter family, some of which are multispecific proteins. There are two known structures of protein (subunits) involved in thiamin uptake in prokaryotes. Binding of thiamin to these proteins is strongly guided by electrostatic interactions. The lack of structural information about thiamin binding proteins for higher organisms remains a bottleneck for understanding the uptake process of thiamin in atomic detail. This review includes recent data on thiamin metabolism, related deficiencies and pathologies, and the latest findings on thiamin binding transporters. © 2014 American Chemical Society. Source

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