Nanometre-sized ! '-martensites , a few nanometres in cross-sectional diameter, formed at intersections of deformation twins, have been found in a heavily deformed 316-type austenitic stainless steel and examined by high-resolution transmission electron microscopy . An orientation relationship was found to be close to the Kurdjumov-Sachs relationship, that is , . HRTEM observations were conducted with a beam direction parallel to . The observed nanometre-sized ! '-martensites exhibited a habit plane and the cross-section of the nanometre-sized ! '-martensites were elongated (...) along [545] % . It has been revealed that the nanometre-sized ! '-martensites of a few nanometres diameter formed at the intersections of deformation twins have a typical habit plane of , which is identical with that reported for a fully grown plate such as ! '-martensite. The origin of the observed habit plane is discussed on the basis of the d 112 ¢ {111} ! shear displacements assisting the % M ! ' transformation. (shrink)

The formation of particles of elemental tin in association with the nucleation of the precipitate phase θ′ in an Al–1.7 at.% Cu–0.01 at.% Sn alloy has been investigated by high resolution transmission electron microscopy. Analysis of lattice images has demonstrated that these tin particles associated with θ′ platelets formed during short-term ageing (typically 3 min at 200 degrees Celcius) exhibit a crystallographic form that is distinctly different from that previously reported in such ternary alloys and also from that observed in (...) the binary alloy Al–0.01 at.% Sn. Those tin particles that could be clearly identified as β-Sn phase shared a crystallographic relationship of the form (001)Sn‖(001)Al‖(001)θ′, [110]Sn‖[100]Al‖[100]θ′ with the α-Al and θ′ phases with which they were simultaneously in contact. The observations imply that, while tin may assist nucleation of platelets of θ′, the formation of θ′ equally influences the crystallography of β--Sn that forms in association with θ′. Following prolonged ageing (typically 50 h at 200°C), the β-Sn particles in contact with θ′ plates had coarsened and diminished in number, and most now exhibited an orientation relationship with α-Al matrix similar to that observed in the binary alloy Al–0.01 at.% Sn (i.e. (100)Sn‖(111)Al, [010]Sn‖[112]Al) and to that previously observed in the later stages of ageing of the ternary alloy Al–1.7 at.% Cu–0.01 at.% Sn. (shrink)

Since its discovery in 1912, X-ray crystallography has become a most useful tool in physics, chemistry, material science, mineralogy, metallurgy, and even in the biological sciences. In 1914, Max von Laue was awarded the Nobel Prize “for the discovery of X-ray diffraction by crystals,” followed by the 1915 Nobel Prize to William Henry Bragg and William Lawrence Bragg “for their services in analysis of crystal structure by means of X-rays.” And these early Nobel prizes marked only the beginning of (...) X-ray crystallography as one of the most fruitful methods in the history of modern science. A 100 years after Laue’s Nobel Prize and 50 years after another Nobel Prize to Dorothy Hodgkin “for her determination by X-ray technique of the structures of important biochemical substances,” the UN proclaimed 2014 the International Year of Crystallography. “In all, 45 scientists have been awarded over the past century for work that is either directly or indirectly related to crystallo .. (shrink)

The time-honored questions concerning the meaning and significance of life should be discussed not only in the light of various philosophical and literary considerations but also from the natural scientific perspectives as human beings are conditioned parts of nature as a whole. Hence, in this paper, I discuss these questions from the perspectives of two major and universal scientific fields, namely, generalized crystallography and quantum mechanics. On the philosophical grounds, the question of the meaning and, especially, the significance of (...) life should be focused on the assumption that each human being is a singular individual whose significance is universal. Such a philosophical approach is compatible with the two above-mentioned natural scientific aspects. (shrink)

Crystallography has proven a rich source of ideas over several centuries. Among the many ways of looking at space groups, N. David Mermin has pioneered the Fourier-space approach. Recently, we have supplemented this approach with methods borrowed from algebraic topology. We now show what topology, which studies global properties of manifolds, has to do with crystallography. No mathematics is assumed beyond what the typical physics or crystallography student will have seen of group theory; in particular, the reader (...) need not have any prior exposure to topology or to cohomology of groups. (shrink)

The Genetic Algorithm (GA) and Simulated Annealing (SA), two techniques for global optimization, were applied to a reduced (simplified) form of the phase problem (RPP) in computational crystallography. Results were compared with those of "enhanced pair flipping" (EPF), a more elaborate problem-specific algorithm incorporating local and global searches. Not surprisingly, EPF did better than the GA or SA approaches, but the existence of GA and SA techniques more advanced than those used in this study suggest that these techniques still (...) hold promise for phase problem applications. The RPP is, furthermore, an excellent test problem for such global optimization methods. (shrink)

This article analyzes the value of geometric models to understand matter with the examples of the Platonic model for the primary four elements (fire, air, water, and earth) and the models of carbon atomic structures in the new science of crystallography. How the geometry of these models is built in order to discover the properties of matter is explained: movement and stability for the primary elements, and hardness, softness and elasticity for the carbon atoms. These geometric models appear to (...) have a double quality: firstly, they exhibit visually the scientific properties of matter, and secondly they give us the possibility to visualize its whole nature. Geometrical models appear to be the expression of the mind in the understanding of physical matter. (shrink)

Objectivity has a history, and it is full of surprises. In Objectivity, Lorraine Daston and Peter Galison chart the emergence of objectivity in the mid-nineteenth-century sciences--and show how the concept differs from its alternatives, truth-to-nature and trained judgment. This is a story of lofty epistemic ideals fused with workaday practices in the making of scientific images. From the eighteenth through the early twenty-first centuries, the images that reveal the deepest commitments of the empirical sciences--from anatomy to crystallography--are those featured (...) in scientific atlases, the compendia that teach practitioners what is worth looking at and how to look at it. Galison and Daston use atlas images to uncover a hidden history of scientific objectivity and its rivals. Whether an atlas maker idealizes an image to capture the essentials in the name of truth-to-nature or refuses to erase even the most incidental detail in the name of objectivity or highlights patterns in the name of trained judgment is a decision enforced by an ethos as well as by an epistemology. As Daston and Galison argue, atlases shape the subjects as well as the objects of science. To pursue objectivity--or truth-to-nature or trained judgment--is simultaneously to cultivate a distinctive scientific self wherein knowing and knower converge. Moreover, the very point at which they visibly converge is in the very act of seeing not as a separate individual but as a member of a particular scientific community. Embedded in the atlas image, therefore, are the traces of consequential choices about knowledge, persona, and collective sight. Objectivity is a book addressed to anyone interested in the elusive and crucial notion of objectivity-- and in what it means to peer into the world scientifically. Lorraine Daston is Director at the Max Planck Institute for the History of Science in Berlin, Germany. She is the coauthor of Wonders and the Order of Nature, 1150-1750 and the editor of Things That Talk: Object Lessons from Art and Science. Peter Galison is Pellegrino University Professor of the History of Science and of Physics at Harvard University. He is the author of Einstein's Clocks, Poincaré's Maps: Empires of Time, How Experiments End, and Image and Logic: A Material Culture of Microphysics, and other books, and coeditor of The Architecture of Science. (shrink)

Many of the earliest books, particularly those dating back to the 1900s and before, are now extremely scarce and increasingly expensive. We are republishing these classic works in affordable, high quality, modern editions, using the original text and artwork.

Change in scientific practice and its implications for the status of scientific claims, examined through an analysis of three episodes at a synchrotron laboratory. After World War II, particle physics became a dominant research discipline in American academia. At many universities, alumni of the Manhattan Project and of Los Alamos were granted resources to start programs of high-energy physics built around the promise of a new and more powerful particle accelerator, the synchrotron. The synchrotron was also a source of very (...) intense X-rays, useful for research in solid states physics and in biology. As synchrotron X-ray science grew, the experimental practice of protein crystallography, garnered funding, prestige, and acclaim. In Velvet Revolution at the Synchrotron, Park Doing examines the change in scientific practice at a synchrotron laboratory as biology rose to dominance over physics. He draws on his own observations and experiences at the Cornell University synchrotron, and considers the implications of that change for the status of scientific claims. Velvet Revolution at the Synchrotron is one of the few recent works in the sociology of science that engages specific scientific and technical claims through participant observation--recorded evocatively and engagingly--to address issues in the philosophy of science. Doing argues that bureaucratic change in science is neither "top-down" nor "bottom-up" but rather performed in and realized through recursively related forums of technical assertion and resistance. He considers the relationship of this change to the content of science, and the implications of this relationship for the project of laboratory studies begun in the late 1970s. (shrink)

ABSTRACT Rosalind Franklin is best known for her informative X-ray diffraction patterns of DNA that provided vital clues for James Watson and Francis Crick's double-stranded helical model. Her scientific career did not end when she left the DNA work at King's College, however. In 1953 Franklin moved to J. D. Bernal's crystallography laboratory at Birkbeck College, where she shifted her focus to the three-dimensional structure of viruses, obtaining diffraction patterns of Tobacco mosaic virus (TMV) of unprecedented detail and clarity. (...) During the next five years, while making significant headway on the structural determination of TMV, Franklin maintained an active correspondence with both Watson and Crick, who were also studying aspects of virus structure. Developments in TMV research during the 1950s illustrate the connections in the emerging field of molecular biology between structural studies of nucleic acids and of proteins and viruses. They also reveal how the protagonists of the “race for the double helix” continued to interact personally and professionally during the years when Watson and Crick's model for the double-helical structure of DNA was debated and confirmed. (shrink)

What I here call Merleau-Ponty’s crystal lamellae corresponds to a phenomenology of the crystal of the interstices of being: the between. Phenomenology’s crystal as I refer to this here is a layered in and through spatial tensions, shimmering, overlapping, intervals magnifying planes and surfaces in all dimensions. This is a crystallography in words to retrace the relations of lived space, tactically navigated, anticipated, recalled, as this experienced awareness of the world around, the places in which we live, especially public (...) spaces, layered in layers, including lattice arrays of space, seen and unseen, including a reflection on art, aesthetic production, especially but not only in Lascaux, and perception, on anger, and the political including the terrorism of capital. (shrink)

In this Monograph, Eva Bonda proposes a new theory of the sense of ‘touch’ in Aristotle’s foundational treatise ‘Περὶ Ψυχῆς’ (On the Soul). The author argues that a delve into the aristoteleian lexicon reveals an intrinsically dialectical theory of the senses, that of all senses being reduced to ‘touch’ either as an experience of polysensoriality or synaeshthesia or of remote sensing touch. ‘Touch’ becomes in Aristotle the thread connecting the matter to its transmutation into the abstract mind. On the basis (...) of neuroimaging results, Eva Bonda describes how the human brain codes, as intangible cognitive phenomena, the body image and the memory through touch. The Monograph is based in Author’s participation at the 2016 World Conference ‘Aristotle 2400 years from his birth’, organized by Aristotle University of Thessaloniki in Greece on 23-28 May 2016. The Congress, in celebration of the 2400th anniversary from Aristotle’s birth, was held in ancient Stageira, the birthplace of Aristotle (born c. 384 BCE) and in ancient Mieza, the place where Aristotle taught Alexander the Great. //Evangelia-Eva Bonda, PhD is Founder and CEO of Neuroaisthesis, a Cognitive Neuroscience Research Company based in Paris since 2005. She has expertise in Cognitive Neuroscience and Neuroimaging, Primate Neuroanatomy, and Clinical Psychotherapy. She studied and conducted research at McGill University in Canada, Université Pierre & Marie Curie in Paris, University of California at Davis and Washingthon University in Saint-Louis in USA, and at Psychology UCL and Crystallography Birkbeck College, University of London, UK. She pioneered neuroimaging experiments in the human brain. Peer-reviewed, 21 illustrations. Available on AMAZON. (shrink)

The Medical Research Council Laboratory of Molecular Biology (formerly the Medical Research Council Unit for the Study of Molecular Structure of Biological Systems) in Cambridge (England) played a key role in the postwar history of molecular biology. The paper, focussing on the early history of the institution, aims to show that the creation of the laboratory and the making of molecular biology were part of a new scientific culture set in place after World War II. In five interlinked parts it (...) deals with the institutional creation of the MRC unit dedicated to the crystallographic analysis of biological molecules; the attraction of postwar biophysics, the heading under which the work of the unit initially fell; the people who joined the laboratory and their appropriation of new technologies, in particular the electronic computer for protein crystal structure determination; the cultural appeal of postwar crystallography, as exemplified in the use of crystal structure diagrams for a wide series of consumer goods at the Festival of Britain in 1951 and the display of molecular models at the Brussels World's Fair in 1958, a key site for the presentation of science and its role in the postwar world. (shrink)

Cryo‐electron microscopy allows the visualization of macromolecules in their native state. Combined with techniques of three‐dimensional reconstruction, cryo‐EM images of single molecules can be used to study macromolecular interactions. The ribosome, a large RNA–protein complex with multiple binding interactions, is an excellent test case illustrating the power of these new techniques. Conformational changes during the binding of tRNA and protein factors to the ribosome can now be studied without the interference of crystal packing. Now that the first X‐ray structures of (...) ribosomal subunits have become available, conformational changes observed by cryo‐EM in different functional states can be traced back to internal rearrangements of the underlying structural framework. Electron microscopy, X‐ray crystallography, and modeling should be used together in the endeavor to understand the functioning of the translational machinery. BioEssays 23:725–732, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

Strong arguments are presented by Hargrave suggesting that the crystallization of visual rhodopsin for high resolution analysis by X-ray crystallography or electron microscopy is feasible. However, the effort needed to achieve this goal will most likely exceed the resources of a single laboratory and a concerted approach to the research is necessary.

The use of computers and the role of women in radio astronomy and X-ray crystallography research at the Cavendish Laboratory between 1949 and 1975 have been investigated. We recorded examples of when computers were used, what they were used for and who used them from hundreds of papers published during these years. The use of the EDSAC, EDSAC 2 and TITAN computers was found to increase considerably over this time-scale and they were used for a diverse range of applications. (...) The majority of references to computer operators and programmers referred to women, 57% for astronomy and 62% for crystallography, in contrast to a very small proportion, 4% and 13% respectively, of female authors of papers. (shrink)

DNA gyrase, an enzyme unique to prokaryotes, has been implicated in almost all processes that involve DNA. Although efficient inhibitors of this protein have been known for more than 20 years, none of them have enjoyed prolonged pharmaceutical success. It is only recently that the mechanisms of inhibition for some of these classes of drugs have been established unequivocally by X‐ray crystallography. It is hoped that this detailed structural information will assist the design of novel, effective inhibitors of DNA (...) gyrase. (shrink)

SummaryWilliam Barlow was an important if unconventional scientist, known for having developed the ‘closest-packing’ atomic models of crystal structure. He resumed an early nineteenth-century tradition of utilizing crystallographical and chemical data to determine atomic arrangements in crystals. This essay recounts Barlow's career and scientific activity in three parts: His place in the tradition of determining atomic arrangement in context of this earlier tradition and of contemporaneous developments of crystallography and chemistry, his unconventional career, and the ‘success’ of his program (...) to determine atomic arrangements in crystals and its influence on the work of William Lawrence Bragg. (shrink)

It was first suggested that the ribosome is associated with protein synthesis in the 1950s. Initially, its components were revealed as surface‐accessible proteins and as molecules of RNA apparently providing a scaffold for subunit shape. Attributing function to the proteins proved difficult, although bacterial protein L11 proved essential for binding one of the decoding protein release factors (RFs). With the discovery that RNA could be a catalyst, interest focussed on the rRNA that, in partnership with mRNA and tRNAs, could potentially (...) mediate the chemical reaction underlying protein synthesis. rRNA interactions and conformational changes were invoked as key elements that facilitated function. The decoding RFs, which are proteins, are exceptions to this rule because they usurp a tRNA function in mediating stop signal recognition. Cryoelectron microscopy and associated image reconstruction technology have now given dramatic snapshots of almost every step of protein synthesis, and X‐ray crystallography has revealed, at last, the subunits and monomeric ribosome in exquisite atomic detail. BioEssays 26:582–588, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

As early as 1981, about 1 year before Shechtman’s discovery of an actual quasicrystal, Alan L. Mackay discussed, in a seminal paper, the first steps for the expansion of crystallography toward its modern phase. In this phase, new possibilities of structures and order, such as the structures of five-fold symmetry, for crystals have been discovered. Medieval Islamic decorators as well as Albrecht Dürer, Johannes Kepler, Roger Penrose, Mackay himself, and other pioneer crystallographers raised important contributions to the theoretical discovery (...) of crystalline possibilities long before or independently of the discovery of their actual existence. In this paper, I discuss further the philosophical significance of Mackay’s theoretical discovery and his contribution to the expansion of pure geometrical crystallography, biological crystallography, and generalized crystallography. (shrink)

In this paper, we review the history of quasicrystals from their sensational discovery in 1982, initially “forbidden” by the rules of classical crystallography, to 2011 when Dan Shechtman was awarded the Nobel Prize in Chemistry. We then discuss the discovery of quasicrystals in philosophical terms of anomalies behavior that led to a paradigm shift as offered by philosopher and historian of science Thomas Kuhn in ‘The Structure of Scientific Revolutions’. This discovery, which found expression in the redefinition of the (...) concept crystal from being periodically arranged to producing sharp peaks in the Bragg diffraction pattern, is analyzed according to the Kuhn Cycle. We relate the quasicrystal revolution to the non-Euclidean geometry revolution and argues that since “great minds think alike” there is a diffusion of ideas between scientific revolutions, or a resonance between different disciplines at different times. The story behind quasicrystals is an excellent example of a paradigm shift, demonstrating the nature of scientific discoveries and breakthroughs. (shrink)

The Medical Research Council Laboratory of Molecular Biology in Cambridge played a key role in the postwar history of molecular biology. The paper, focussing on the early history of the institution, aims to show that the creation of the laboratory and the making of molecular biology were part of a new scientific culture set in place after World War II. In five interlinked parts it deals with the institutional creation of the MRC unit dedicated to the crystallographic analysis of biological (...) molecules; the attraction of postwar biophysics, the heading under which the work of the unit initially fell; the people who joined the laboratory and their appropriation of new technologies, in particular the electronic computer for protein crystal structure determination; the cultural appeal of postwar crystallography, as exemplified in the use of crystal structure diagrams for a wide series of consumer goods at the Festival of Britain in 1951 and the display of molecular models at the Brussels World’s Fair in 1958, a key site for the presentation of science and its role in the postwar world. (shrink)

Several recent studies of early modern natural philosophy have claimed that corpuscularism and experimental philosophy were sharply distinct or even conflicting views. This chapter provides a different perspective on the relation between corpuscularism and experimental philosophy by examining Domenico Guglielmini’s ‘Philosophical Reflections’ on salts (1688). This treatise on crystallography develops a corpuscularist theory and defends it in a way that is in line with the methodological prescriptions, epistemological strictures, and preferred argumentative styles of experimental philosophers. The examination of the (...) ‘Reflections’ shows that early modern philosophers could consistently endorse, at the same time, corpuscularism and experimental philosophy. (shrink)

Scientific models share one central characteristic with fiction: their relation to the physical world is ambiguous. It is often unclear whether an element in a model represents something in the world or presents an artifact of model building. Fiction, too, can resemble our world to varying degrees. However, we assign a different epistemic function to scientific representations. As artifacts of human activity, how are scientific representations allowing us to make inferences about real phenomena? In reply to this concern, philosophers of (...) science have started analyzing scientific representations in terms of fictionalization strategies. Many arguments center on a dyadic relation between the model and its target system, focusing on structural resemblances and “as if” scenarios. This chapter provides a different approach. It looks more closely at model building to analyze the interpretative strategies dealing with the representational limits of models. How do we interpret ambiguous elements in models? Moreover, how do we determine the validity of model-based inferences to information that is not an explicit part of a representational structure? I argue that the problem of ambiguous inference emerges from two features of representations, namely their hybridity and incompleteness. To distinguish between fictional and non-fictional elements in scientific models my suggestion is to look at the integrative strategies that link a particular model to other methods in an ongoing research context. To exemplify this idea, I examine protein modeling through X-ray crystallography as a pivotal method in biochemistry. (shrink)

Structural biology has experienced several transformative technological advances in recent years. These include: development of extremely bright X-ray sources and the use of electrons to extend protein crystallography to ever decreasing crystal sizes; and an increase in the resolution attainable by cryo-electron microscopy. Here we discuss the use of these techniques in general terms and highlight their application for biological filament systems, an area that is severely underrepresented in atomic resolution structures. We assemble a model of a capped tropomyosin-actin (...) minifilament to demonstrate the utility of combining structures determined by different techniques. Finally, we survey the methods that attempt to transform high resolution structural biology into more physiological environments, such as the cell. Together these techniques promise a compelling decade for structural biology and, more importantly, they will provide exciting discoveries in understanding the designs and purposes of biological machines. Structural biology is undergoing technological advancements that now reveal the structures of previously inaccessible biological machines. Microfocus synchrotron beamlines, X-ray free electron lasers, and MicroED cope with vanishingly small crystals, while cryo-electron microscopy targets single molecules at near atomic resolution. These advances promise an exciting decade for structural biology. (shrink)