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This revised second edition of the author's classic text offers readers a comprehensively updated review of relativistic atomic many-body theory, covering the many developments in the field since the publication of the original title. In particular, a new final section extends the scope to cover the evaluation of QED effects for dynamical processes. The treatment of the book is based upon quantum-field theory, and demonstrates that when the procedure is carried to all orders of perturbation theory, two-particle systems are fully compatible with the relativistically covariant Bethe-Salpeter equation. This procedure can be applied to arbitrary open-shell systems, in analogy with the standard many-body theory, and it is also applicable to systems with more than two particles. Presently existing theoretical procedures for treating atomic systems are, in several cases, insufficient to explain the accurate experimental data recently obtained, particularly for highly charged ions. The main text is divided into three parts. In Part I, the standard time-independent and time-dependent perturbation procedures are reviewed. This includes a new section at the end of chapter 2 concerning the so-called "Fock-space procedure" or "Coulomb-only procedure" for relativistic-QED calculations. This is a procedure on an intermediate level, frequently u sed in recent time by chemists on molecular systems, where a full QED treatment is out of question. Part II describes three methods for QED calculations, a) the standard S-matrix formulation, b) the Two-times Green's-function method, developed by the St Petersburg Atomic Theory group, and c) the Covariant-evolution operator (CEO) method, recently developed by the Gothenburg Atomic Theory group. In Part III, the CEO method is combined with electron correlation to arbitrary order to a unified MBPT-QED procedure. The new Part IV includes two new chapters dealing with dynamical properties and how QED effects can be evaluated for such process

This book will cover the cutting-edge developments in molecular and cellular mechanobiology to date. Readers will have a clear understanding of mechanobiology at the molecular and cellular levels, encompassing the mechanosensors, transducers, and transcription. An integrative approach across different scales from molecular sensing to mechanotransduction and gene modulation for physiological regulation of cellular functions will be explored, as well as applications to pathophysiological states in disease. A comprehensive understanding of the roles of physicochemical microenvironment and intracellular responses in determining cellular function in health and disease will also be discussed.

The biological membranes of cellular organization enfold an important group of membrane proteins called the ATPases, which are not only versatile in maintaining chemical gradient and electrical potential across the membrane but also bring metabolites necessary for cell metabolism and drive out toxins, waste products and solutes that otherwise can curb cell functions. ATPases are distributed virtually in all live forms starting from unicellular to multicellular and also in viruses. There are different types of ATPases, which differ in function and structure and in the type of ions they transport. The three main types of the ion pump ATPase family are: (i) P-type ATPases that transport different ions across membranes and Ca2+ATPases belongs to this catagory (ii) F-type ATPase in mitochondria, chloroplasts and bacterial plasma membranes produce ATP using the proton gradient; and (iii) V-type ATPase catalyzes ATP hydrolysis to transport solutes and maintains acidic pH in organelles like lysosomes. Genetic defects in either of the ATPases cause several diseases and a number of researches have demonstrated the involvement of the members of ATPases in the cell pathology and diseases, thereby penetrating exciting new areas of our understanding. In this book, the authors summarize recent knowledge about the molecular mechanisms associated with Ca2+-ATPase, V-ATPase and F-ATPase in intracellular and extracellular Ca2+ transport, mitochondrial ATP synthase, vesicular H+ transport, and lysosomal pH regulation. This book thereby bridges the gap between fundamental research and biomedical and pharmaceutical applications. The book provides an informative resource to improve ATPase research and modern therapeutic approaches toward different life threatening diseases that are associated with dysregulation of the ATPases.

This text provides an introduction to the science that governs the interaction of light and matter (in the gas phase). It provides readers with the basic knowledge to exploit the light-matter interaction to develop quantitative tools for gas analysis (i.e. optical diagnostics) and understand and interpret the results of spectroscopic measurements. The authors pair the basics of gas‐phase spectroscopy with coverage of key optical diagnostic techniques utilized by practicing engineers and scientists to measure fundamental flow‐field properties. The text is organized to cover three sub‐topics of gas‐phase spectroscopy: (1) spectral line positions, (2) spectral line strengths, and (3) spectral lineshapes by way of absorption, emission, and scattering interactions. The latter part of the book describes optical measurement techniques and equipment. Key subspecialties include laser induced fluorescence, tunable laser absorption spectroscopy, and wavelength modulation spectroscopy. It is ideal for students and practitioners across a range of applied sciences including mechanical, aerospace, chemical, and materials engineering.

This book will cover the cutting-edge developments in molecular and cellular mechanobiology to date. Readers will have a clear understanding of mechanobiology at the molecular and cellular levels, encompassing the mechanosensors, transducers, and transcription. An integrative approach across different scales from molecular sensing to mechanotransduction and gene modulation for physiological regulation of cellular functions will be explored, as well as applications to pathophysiological states in disease. A comprehensive understanding of the roles of physicochemical microenvironment and intracellular responses in determining cellular function in health and disease will also be discussed.

This revised second edition of the author's classic text offers readers a comprehensively updated review of relativistic atomic many-body theory, covering the many developments in the field since the publication of the original title. In particular, a new final section extends the scope to cover the evaluation of QED effects for dynamical processes. The treatment of the book is based upon quantum-field theory, and demonstrates that when the procedure is carried to all orders of perturbation theory, two-particle systems are fully compatible with the relativistically covariant Bethe-Salpeter equation. This procedure can be applied to arbitrary open-shell systems, in analogy with the standard many-body theory, and it is also applicable to systems with more than two particles. Presently existing theoretical procedures for treating atomic systems are, in several cases, insufficient to explain the accurate experimental data recently obtained, particularly for highly charged ions. The main text is divided into three parts. In Part I, the standard time-independent and time-dependent perturbation procedures are reviewed. This includes a new section at the end of chapter 2 concerning the so-called "Fock-space procedure" or "Coulomb-only procedure" for relativistic-QED calculations. This is a procedure on an intermediate level, frequently u sed in recent time by chemists on molecular systems, where a full QED treatment is out of question. Part II describes three methods for QED calculations, a) the standard S-matrix formulation, b) the Two-times Green's-function method, developed by the St Petersburg Atomic Theory group, and c) the Covariant-evolution operator (CEO) method, recently developed by the Gothenburg Atomic Theory group. In Part III, the CEO method is combined with electron correlation to arbitrary order to a unified MBPT-QED procedure. The new Part IV includes two new chapters dealing with dynamical properties and how QED effects can be evaluated for such process

This text provides an introduction to the science that governs the interaction of light and matter (in the gas phase). It provides readers with the basic knowledge to exploit the light-matter interaction to develop quantitative tools for gas analysis (i.e. optical diagnostics) and understand and interpret the results of spectroscopic measurements. The authors pair the basics of gas‐phase spectroscopy with coverage of key optical diagnostic techniques utilized by practicing engineers and scientists to measure fundamental flow‐field properties. The text is organized to cover three sub‐topics of gas‐phase spectroscopy: (1) spectral line positions, (2) spectral line strengths, and (3) spectral lineshapes by way of absorption, emission, and scattering interactions. The latter part of the book describes optical measurement techniques and equipment. Key subspecialties include laser induced fluorescence, tunable laser absorption spectroscopy, and wavelength modulation spectroscopy. It is ideal for students and practitioners across a range of applied sciences including mechanical, aerospace, chemical, and materials engineering.

The work presented in this thesis involves a number of sophisticated experiments highlighting novel applications of the Pixel Imaging Mass Spectrometry (PImMS) camera in the field of photoinduced molecular dynamics. This approach represents the union of a new enabling technology (a multiple memory register, CMOS-based pixel detector) with several modern chemical physics approaches and represents a significant leap forward in capabilities. Applications demonstrated include three-dimensional imaging of photofragment Newton spheres, simultaneous electron-ion detection using a single sensor, and ion-ion velocity correlation measurements that open the door to novel covariance imaging experiments. When combined with Coulomb explosion imaging, such an approach is demonstrated to allow the measurement of molecular structure and motion on a femtosecond timescale. This is illustrated through the controlled photoexcitation of torsional motion in biphenyl molecules and the subsequent real-time measurement of the torsional angle.

This book provides the first complete and up-to-date summary of the state of the art in HAXPES and motivates readers to harness its powerful capabilities in their own research. The chapters are written by experts. They include historical work, modern instrumentation, theory and applications. This book spans from physics to chemistry and materials science and engineering. In consideration of the rapid development of the technique, several chapters include highlights illustrating future opportunities as well.

This second edition was updated to include some of the recent developments, such as “increased-valence” structures for 3-electron-3-centre bonding, benzene, electron conduction and reaction mechanisms, spiral chain O4 polymers and recoupled-pair bonding. The author provides qualitative molecular orbital and valence-bond descriptions of the electronic structures for primarily electron-rich molecules, with strong emphasis given to the valence-bond approach that uses “increased-valence” structures. He describes how “long-bond” Lewis structures as well as standard Lewis structures are incorporated into “increased-valence” structures for electron-rich molecules. “Increased-valence” structures involve more electrons in bonding than do their component Lewis structures, and are used to provide interpretations for molecular electronic structure, bond properties and reactivities. Attention is also given to Pauling “3-electron bonds”, which are usually diatomic components of “increased-valence” structures for electron-rich molecules.

This thesis discusses an approach to excite potassium atoms to very highly excited states (Rydberg states), and then tune their energy levels to induce resonant collisions between atoms. Potassium gas is super-cooled to 1 mK and confined to a small volume in a magneto-optical trap. A 405 nm laser diode, electronically locked to a potassium vapor cell via Doppler free spectroscopy, excites these atoms from the 4s1/2 state (ground state) to the 5p3/2 state. A 978 nm laser then excites the 5p3/2 to nd3/2 or nd5/2 transition, creating Rydberg atoms. Since there is no ground state reference for this transition, an alternative method must be used to lock the laser's frequency. A scanning transfer cavity lock transfers the stability of a 632 nm HeNe reference laser to the unstable 978 nm laser diode by passing both lasers through a Fabry-Perot interferometer. Once Rydberg atoms have been created, their energy levels are tuned with an external electric field so that collisions between atoms cause resonant atomic transitions to different Rydberg states. The Rydberg atoms are ionized with a second, stronger electric field, and detected by microchannel plate detectors. Rydberg atoms with different principal quantum numbers ionize at different electric field strengths, so a successful collision signal has multiple peaks from the microchannel plates.

This volume explores microRNA pathophysiology, focusing on basic concepts in molecular and cellular biology. Chapters contributed by leading scientists examine recently discovered pathways in several processes, including aging, diabetes, cardiovascular disease, hematopoiesis, and mitochondrial fitness. The authors contextualize microRNAs within epigenetics and micropeptidomics, angiongenesis and atherosclerosis, endometrial pathophysiology, and more. Throughout, numerous color photographs, diagrams of molecular pathways, and tables enhance the text. microRNA: Basic Science is an ideal companion to both microRNA: Medical Evidence and microRNA: Cancer. Taken together, these three books provide a state-of-the-art overview of this rapidly-expanding and fascinating field, from the molecular level to clinical practice. It will be invaluable to medical students, physicians, and researchers, as a complete and unique guide in the exploration of microRNA in basic science, cancer and clinical practice.

The book will discuss classes of proteins and their folding, as well as the involvement of bioinformatics in solving the protein folding problem. In vivo and in vitro folding mechanisms are examined, as well as the failures of in vitro folding, a mechanism helpful in understanding disease caused by misfolding. The role of energy landscapes is also discussed and the computational approaches to these landscapes.

This textbook, now in its third edition, provides a formative introduction to the structure of matter that will serve as a sound basis for students proceeding to more complex courses, thus bridging the gap between elementary physics and topics pertaining to research activities. The focus is deliberately limited to key concepts of atoms, molecules and solids, examining the basic structural aspects without paying detailed attention to the related properties. For many topics the aim has been to start from the beginning and to guide the reader to the threshold of advanced research. This edition includes four new chapters dealing with relevant phases of solid matter (magnetic, electric and superconductive) and the related phase transitions. The book is based on a mixture of theory and solved problems that are integrated into the formal presentation of the arguments. Readers will find it invaluable in enabling them to acquire basic knowledge in the wide and wonderful field of condensed matter and to understand how phenomenological properties originate from the microscopic, quantum features of nature.

This book is an attempt to bridge the gap between the instrumental principles of multi-dimensional time-correlated single photon counting (TCSPC) and typical applications of the technique. Written by an originator of the technique and by sucessful users, it covers the basic principles of the technique, its interaction with optical imaging methods and its application to a wide range of experimental tasks in life sciences and clinical research. The book is recommended for all users of time-resolved detection techniques in biology, bio-chemistry, spectroscopy of live systems, live cell microscopy, clinical imaging, spectroscopy of single molecules, and other applications that require the detection of low-level light signals at single-photon sensitivity and picosecond time resolution.

These seven lectures are intended to serve as an introduction for beginning graduate students to the spectra of small molecules. The author succeeds in illustrating the concepts by using language and metaphors that capture and elegantly convey simple insights into dynamics that lie beyond archival molecular constants. The lectures can simultaneously be viewed as a collection of interlocking special topics that have fascinated the author and his students over the years. Though neither a textbook nor a scholarly monograph, the book provides an illuminating perspective that will benefit students and researchers alike.

This work addresses the computation of excited-state properties of systems containing thousands of atoms. To achieve this, the author combines the linear response formulation of time-dependent density functional theory (TDDFT) with linear-scaling techniques known from ground-state density-functional theory. This extends the range of TDDFT, which on its own cannot tackle many of the large and interesting systems in materials science and computational biology. The strengths of the approach developed in this work are demonstrated on a number of problems involving large-scale systems, including exciton coupling in the Fenna-Matthews-Olson complex and the investigation of low-lying excitations in doped p-terphenyl organic crystals. .

This volume explores microRNA function in a wide array of human disorders, providing a clinical basis for precision medicine and personalized therapies using these molecules. The twenty-one chapters, all authored by internationally-renowned experts, open with an introduction contextualizing microRNA manipulation within today’s initiatives towards precision medicine. The following chapters explore the clinical role of microRNAs in the diagnosis and treatment of metabolic and cardiovascular disorders, focusing on mitochondrial fitness, arterial hypertension, cardiovascular remodeling, cerebrovascular disease, pulmonary hypertension, diabetic kidney disease, and kidney transplantation. The subsequent chapters discuss the importance of microRNAs in the wound healing process and in skin disease, in the pathogenesis of allergy, in human ovulation, and in infection. The book concludes with chapters which outline the emerging role of microRNAS in doping and detail microRNA profiling. microRNA: Medical Evidence is an ideal companion to both microRNA: Basic Science and microRNA: Cancer. Taken together, these three books provide a state-of-the-art overview of this rapidly-expanding and fascinating field, from the molecular level to clinical practice. It will be invaluable to medical students, physicians, and researchers, as a complete and unique guide in the exploration of microRNA in basic science, cancer and clinical practice.

This book is devoted to the calculation of hot-plasma properties which generally requires a huge number of atomic data. It is the first book that combines information on the details of the basic atomic physics and its application to atomic spectroscopy with the use of the relevant statistical approaches. Information like energy levels, radiative rates, collisional and radiative cross-sections, etc., must be included in equilibrium or non-equilibrium models in order to describe both the atomic-population kinetics and the radiative properties. From the very large number of levels and transitions involved in complex ions, some statistical (global) properties emerge. The book presents a coherent set of concepts and compact formulas suitable for tractable and accurate calculations. The topics addressed are: radiative emission and absorption, and a dozen of other collisional and radiative processes; transition arrays between level ensembles (configurations, superconfigurations); effective temperatures of configurations, superconfigurations, and ions; charge-state distributions; radiative power losses and opacity. There are many numerical examples and comparisons with experiment presented throughout the book. The plasma properties described in this book are especially relevant to large nuclear fusion facilities such as the NIF (California) and the ITER (France), and to astrophysics. Methods relevant to the central-field configurational model are described in detail in the appendices: tensor-operator techniques, second-quantization formalism, statistical distribution moments, and the algebra of partition functions. Some extra tools are propensity laws, correlations, and fractals. These methods are applied to the analytical derivation of many properties, specially the global ones, through which the complexity is much reduced. The book is intended for graduate-level students, and for physicists working in the field.

Although the fission of heavy nuclei was discovered over 75 years ago, many problems and questions still remain to be addressed and answered. The reader will be presented with an old, but persistent problem of this field: The contradiction between Prompt Fission Neutron (PFN) spectra measured with differential (microscopic) experiments and integral (macroscopic and benchmark) experiments (the Micro-Macro problem). The difference in average energy is rather small ~3% but it is stable and we cannot explain the difference due to experimental uncertainties. Can we measure the PFN spectrum with high accuracy? How may we compare results of different experiments to provide better accuracy? Are our traditional theoretical models correct? What can be done to solve the Micro-Macro problem in future? These questions are discussed in this monograph for the reader. The current work will be of interest to graduate students and researchers, particularly those working in nuclear and neutron physics.

Although the fission of heavy nuclei was discovered over 75 years ago, many problems and questions still remain to be addressed and answered. The reader will be presented with an old, but persistent problem of this field: The contradiction between Prompt Fission Neutron (PFN) spectra measured with differential (microscopic) experiments and integral (macroscopic and benchmark) experiments (the Micro-Macro problem). The difference in average energy is rather small ~3% but it is stable and we cannot explain the difference due to experimental uncertainties. Can we measure the PFN spectrum with high accuracy? How may we compare results of different experiments to provide better accuracy? Are our traditional theoretical models correct? What can be done to solve the Micro-Macro problem in future? These questions are discussed in this monograph for the reader. The current work will be of interest to graduate students and researchers, particularly those working in nuclear and neutron physics.

This thesis presents a highly innovative study of the ultrafast structural and vibrational dynamics of hydrated phospholipids, the basic constituents of cell membranes. As a novel approach to the water-phospholipid interface, the author studies phosphate vibrations using the most advanced methods of nonlinear vibrational spectroscopy, including femtosecond two-dimensional infrared spectroscopy. He shows for the first time that the structure of interfacial water undergoes very limited fluctuations on a 300 fs time scale and that the lifetimes of hydrogen bonds with the phospholipid are typically longer than 10 ps. Such properties originate from the steric hindrance of water fluctuations at the interface and the orienting action of strong electric fields from the phospholipid head group dipoles. In an extensive series of additional experiments, the vibrational lifetimes of the different vibrations and the processes of energy dissipation are elucidated in detail.

This thesis addresses the development of a new force spectroscopy tool, correlation force spectroscopy (CFS) for the measurement of the properties of very small volumes of material (molecular to m3) at kHz-MHz frequency range. CFS measures the simultaneous thermal fluctuations of two closely-spaced atomic force microscopy (AFM) cantilevers. CFS then calculates the cross-correlation in the thermal fluctuations that gives the mechanical properties of the matter that spans the gap of the two cantilevers. The book also discusses development of CFS, its advantages over AFM, and its application in single molecule force spectroscopy and micro-rheology.

Arterial stiffness is an emerging risk factor with important implications for cardiovascular disease risk. Herein, we concisely summarize the physiological and pathophysiological aspects of arterial stiffening, and highlight the importance of increased arterial stiffness for future cardiovascular events. Factors contributing to increased arterial stiffness such as advancing age, obesity, race, sex differences and cardiorespiratory fitness are examined while elucidating the potential underlying mechanisms for each scenario. To conclude, we discuss novel interventions to prevent and/or reverse the arterial stiffening process in order to reduce cardiovascular risk. This book also: Overviews the cellular and molecular mechanisms of arterial stiffness Discusses the implications of arterial stiffness in target organ damage.

This book is devoted to the calculation of hot-plasma properties which generally requires a huge number of atomic data. It is the first book that combines information on the details of the basic atomic physics and its application to atomic spectroscopy with the use of the relevant statistical approaches. Information like energy levels, radiative rates, collisional and radiative cross-sections, etc., must be included in equilibrium or non-equilibrium models in order to describe both the atomic-population kinetics and the radiative properties. From the very large number of levels and transitions involved in complex ions, some statistical (global) properties emerge. The book presents a coherent set of concepts and compact formulas suitable for tractable and accurate calculations. The topics addressed are: radiative emission and absorption, and a dozen of other collisional and radiative processes; transition arrays between level ensembles (configurations, superconfigurations); effective temperatures of configurations, superconfigurations, and ions; charge-state distributions; radiative power losses and opacity. There are many numerical examples and comparisons with experiment presented throughout the book. The plasma properties described in this book are especially relevant to large nuclear fusion facilities such as the NIF (California) and the ITER (France), and to astrophysics. Methods relevant to the central-field configurational model are described in detail in the appendices: tensor-operator techniques, second-quantization formalism, statistical distribution moments, and the algebra of partition functions. Some extra tools are propensity laws, correlations, and fractals. These methods are applied to the analytical derivation of many properties, specially the global ones, through which the complexity is much reduced. The book is intended for graduate-level students, and for physicists working in the field.

This thesis presents a highly innovative study of the ultrafast structural and vibrational dynamics of hydrated phospholipids, the basic constituents of cell membranes. As a novel approach to the water-phospholipid interface, the author studies phosphate vibrations using the most advanced methods of nonlinear vibrational spectroscopy, including femtosecond two-dimensional infrared spectroscopy. He shows for the first time that the structure of interfacial water undergoes very limited fluctuations on a 300 fs time scale and that the lifetimes of hydrogen bonds with the phospholipid are typically longer than 10 ps. Such properties originate from the steric hindrance of water fluctuations at the interface and the orienting action of strong electric fields from the phospholipid head group dipoles. In an extensive series of additional experiments, the vibrational lifetimes of the different vibrations and the processes of energy dissipation are elucidated in detail.

This volume explores microRNA pathophysiology, focusing on basic concepts in molecular and cellular biology. Chapters contributed by leading scientists examine recently discovered pathways in several processes, including aging, diabetes, cardiovascular disease, hematopoiesis, and mitochondrial fitness. The authors contextualize microRNAs within epigenetics and micropeptidomics, angiongenesis and atherosclerosis, endometrial pathophysiology, and more. Throughout, numerous color photographs, diagrams of molecular pathways, and tables enhance the text. microRNA: Basic Science is an ideal companion to both microRNA: Medical Evidence and microRNA: Cancer. Taken together, these three books provide a state-of-the-art overview of this rapidly-expanding and fascinating field, from the molecular level to clinical practice. It will be invaluable to medical students, physicians, and researchers, as a complete and unique guide in the exploration of microRNA in basic science, cancer and clinical practice.

This book introduces systematically the operator method for the solution of the Schr dinger equation. This method permits to describe the states of quantum systems in the entire range of parameters of Hamiltonian with a predefined accuracy. The operator method is unique compared with other non-perturbative methods due to its ability to deliver in zeroth approximation the uniformly suitable estimate for both ground and excited states of quantum system. The method has been generalized for the application to quantum statistics and quantum field theory. In this book, the numerous applications of operator method for various physical systems are demonstrated. Simple models are used to illustrate the basic principles of the method which are further used for the solution of complex problems of quantum theory for many-particle systems. The results obtained are supplemented by numerical calculations, presented as tables and figures.

This thesis addresses the development of a new force spectroscopy tool, correlation force spectroscopy (CFS) for the measurement of the properties of very small volumes of material (molecular to m3) at kHz-MHz frequency range. CFS measures the simultaneous thermal fluctuations of two closely-spaced atomic force microscopy (AFM) cantilevers. CFS then calculates the cross-correlation in the thermal fluctuations that gives the mechanical properties of the matter that spans the gap of the two cantilevers. The book also discusses development of CFS, its advantages over AFM, and its application in single molecule force spectroscopy and micro-rheology.

Structure-property relationships of two crystal structures were investigated using computational methodologies in two different length scales:electronic and atomistic length scales. Electronic structure calculations were performed using density functional theory (DFT) with generalized gradient approximation (GGA), GGA+U (U is "on-site" electronelectron repulsion) and hybrid functional forms. Atomistic calculations were performed utilizing the semi-empirical interatomic formulation, Modified Embedded Atom Method (MEAM). Classical molecular dynamics simulations were performed on the atomistic length scale in order to investigate thermal properties. In the first study, structural, elastic and thermal properties of cementite (Fe₃C) were investigated using a Modified Embedded Atom Method (MEAM) potential for iron-carbon (Fe-C) alloys. Previously developed Fe and C single element potentials were used to develop a Fe-C alloy MEAM potential, using a statistically-based optimization scheme to reproduce structural and elastic properties of cementite, the interstitial energies of C in bcc Fe as well as heat of formation of Fe-C alloys in L₁₂ and B₁ structures. The stability of cementite at high temperatures was investigated by molecular dynamics simulations. The nine single crystal elastic constants for cementite were obtained by computing total energies for strained cells. Polycrystalline elastic moduli for cementite were calculated from the single crystal elastic constants of cementite. The formation energies of (001), (010), and (100) surfaces of cementite were also calculated. The melting temperature and the variation of both the specific heat and volume with respect to temperature were investigated by performing a two-phase (solid/liquid) molecular dynamics simulation of cementite. The predictions of the potential are in good agreement with first-principles calculations and experiments. In the second study the site occupancy and magnetic properties of Zn-Sn substituted M-type Sr-hexaferrite (SrFe₁₂x̳(Zn₀.₅Sn₀.₅)x̳O₁₉ with x = 1) were investigated using firstprinciples total-energy calculations. We find that in the ground-state configuration Zn-Sn ions preferentially occupy 4f₁ and 4f₂ sites unlike the model previously suggested by Ghasemi et al. where Zn-Sn ions occupy 2b and 4f₂ sites. Our model predicts a rapid increase in saturation magnetic moment (Ms̳) as well as decrease in magnetic anisotropy compared to the pure M-type Sr-hexaferrite, which is consistent with experimental observations.