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1.
n the occasion of the 150th anniversary of his death, the scientific work of the famous German anatomist Johann Friedrich Meckel (1781 to 1833) in Halle is appreciated. The Younger Meckel is counted to the most outstanding figures in the history of anatomy and medicine in the first third of 19th century. According to his founded knowledges in the normal, comparative, and pathologic anatomy and embryology he was able to give a scientific argument of malformations first of all in the history of medicine and biology. The edition of Meckel's Handbook of Pathologic Anatomy (in German language; 1st vol. 1812) is the birth of scientific teratology. Through his contributions to teratology Meckel directly participated in the raising of general pathology and pathologic anatomy to scientific disciplines. Meckel's interceding for C. F. Wolff's theory of epigenesis, not at last by translation of Wolff's paper "De formatione intestinorum" (1768 to 1769) into the German language, accelerated the development of the general and special embryology during the 19th century. In the contemporary medicine the succeeding eponyms are reminding of the imposing German physician and anatomist: the Meckel's diverticulum of ileum (1809), the Meckel's cartilage of the mandibular arch (1820) and the so-called Meckel syndrome (1822).  相似文献   

2.
Jang IG  Kim IY 《Journal of biomechanics》2008,41(11):2353-2361
In the field of bone adaptation, it is believed that the morphology of bone is affected by its mechanical loads, and bone has self-optimizing capability; this phenomenon is well known as Wolff's law of the transformation of bone. In this paper, we simulated trabecular bone adaptation in the human proximal femur using topology optimization and quantitatively investigated the validity of Wolff's law. Topology optimization iteratively distributes material in a design domain producing optimal layout or configuration, and it has been widely and successfully used in many engineering fields. We used a two-dimensional micro-FE model with 50 microm pixel resolution to represent the full trabecular architecture in the proximal femur, and performed topology optimization to study the trabecular morphological changes under three loading cases in daily activities. The simulation results were compared to the actual trabecular architecture in previous experimental studies. We discovered that there are strong similarities in trabecular patterns between the computational results and observed data in the literature. The results showed that the strain energy distribution of the trabecular architecture became more uniform during the optimization; from the viewpoint of structural topology optimization, this bone morphology may be considered as an optimal structure. We also showed that the non-orthogonal intersections were constructed to support daily activity loadings in the sense of optimization, as opposed to Wolff's drawing.  相似文献   

3.
In 1866, at the C. Ludwig's laboratory, E. F. Cyon discovered n. depressor, and after C. Bernard's presentation he was awarded with the Montion Prize of the Paris Academy of Sciences. In 1867, together with his brother M. Cyon, he discovered nn. accelerantes of heart, which increase the heart rate when being stimulated. From 1868 to 1874 he was a privatdocent an professor of physiology at Saint-Petersburg University, where under his guidance I.P. Pavlov mastered the brilliant technique of vivisection experiment and accomplished his first works on the physiology of circulation and digestion. From 1872 to 1874 E. F. Cyon was physiology professor at Saint-Petersburg Medical-Surgical Academy. He published "Course of Physiology" in 2 volumes, the official speech "Heart and Brain" and others, proposed an original theory of inhibition, improved the reflex theory. He published 197 works, including 151 in German and French. I. P. Pavlov paid a worthy tribute to his teacher and continued the main direction of his investigations.  相似文献   

4.
This paper seeks to reinterpret the life and work of J. B. S. Haldane by focusing on an illuminating but largely ignored essay he published in1927, “The Last Judgment” – the sequel to his better known work, Daedalus (1924). This astonishing essay expresses a vision of the human future over the next 40,000,000 years, one that revises and updates Wellsian futurism with the long range implications of the “new biology” for human destiny. That vision served as a kind of lifelong credo, one that infused and informed his diverse scientific work, political activities, and popular writing, and that gave unity and coherence to his remarkable career. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

5.
The law of bone remodeling, commonly referred to as Wolff's Law, asserts that the internal trabecular bone adapts to external loadings, reorienting with the principal stress trajectories to maximize mechanical efficiency creating a naturally optimum structure. The goal of the current study was to utilize an advanced structural optimization algorithm, called design space optimization (DSO), to perform a micro-level three-dimensional finite element bone remodeling simulation on the human proximal femur and analyse the results to determine the validity of Wolff's hypothesis. DSO optimizes the layout of material by iteratively distributing it into the areas of highest loading, while simultaneously changing the design domain to increase computational efficiency. The result is a "fully stressed" structure with minimized compliance and increased stiffness. The large-scale computational simulation utilized a 175 μm mesh resolution and the routine daily loading activities of walking and stair climbing. The resulting anisotropic trabecular architecture was compared to both Wolff's trajectory hypothesis and natural femur samples from literature using a variety of visualization techniques, including radiography and computed tomography (CT). The results qualitatively revealed several anisotropic trabecular regions, that were comparable to the natural human femurs. Quantitatively, the various regional bone volume fractions from the computational results were consistent with quantitative CT analyses. The global strain energy proceeded to become more uniform during optimization; implying increased mechanical efficiency was achieved. The realistic simulated trabecular geometry suggests that the DSO method can accurately predict bone adaptation due to mechanical loading and that the proximal femur is an optimum structure as the Wolff hypothesized.  相似文献   

6.
It is difficult to completely understand the life history of an intellectual excluding an understanding of his family upbringing and formative years. Family upbringing and childhood environment, often the less known part of a life history, play crucial roles in shaping the ideas and values individuals espouse in their adult life. Notwithstanding, this paper is not concerned with Don C. Ohadike’s childhood. It rather focuses on the professional career of our able historian – that is the part of his life as revealed by his most outstanding published writings. Ohadike’s published works contain a wellspring of idioms that tell much about his values, quality of mind, and his mission as an African historian. Ohadike was a humanist, an African patriot, and a nationalist crusader. His entire philosophy centered on safeguarding his African identity in an emergent world of cultural imperialism. The funds for this research were provided by a NEH-funded fellowship at the Schomburg Center, New York in the Spring of 2007. I owe a lot of gratitude to Professor John McLeod and Dean Blaine Hudson for granting me the extra incentives to pursue my research in New York. While all errors and misinterpretations are mine, I wish to thank the editors and anonymous reviewers for Journal of Dialectical Anthropology for their perspective comments and suggestions on earlier drafts of this paper.  相似文献   

7.
The correct explanation for the freemartin phenotype in the female twin of a female-male pair in cattle was first reported by Tandler and Keller (1911. Deutsche Tier?rzt Wochenschr 19:148-149). This same explanation for the freemartin was independently discovered by Lillie (1916. Science 43:611-613). Today both set of scientists are given credit for this discovery; it is the basis for much of the subsequent work on the developmental basis for sex differentiation in vertebrates. Even though Lillie published after Keller and Tandler, he gets credit for this discovery because: (1) Keller and Tandler published in a veterinary journal and as a consequence their work was not disseminated as broadly throughout the larger scientific community; this problem was compounded by the fact that their definitive 1916 paper was published under wartime conditions during World War I, and (2) Lillie was an influential scientist with a group of graduate students who could elaborate on and extend his work; they published a number of papers on the freemartin. At some point while Lillie was doing his initial work on the freemartin he may have become aware that Keller and Tandler were also working on the freemartin problem; this information may have shaped his decision on when to publish.  相似文献   

8.
Wolff's law of trabecular architecture at remodeling equilibrium   总被引:10,自引:0,他引:10  
An elastic constitutive relation for cancellous bone tissue is developed. This relationship involves the stress tensor T, the strain tensor E and the fabric tensor H for cancellous bone. The fabric tensor is a symmetric second rank tensor that is a quantitative stereological measure of the microstructural arrangement of trabeculae and pores in the cancellous bone tissue. The constitutive relation obtained is part of an algebraic formulation of Wolff's law of trabecular architecture in remodeling equilibrium. In particular, with the general constitutive relationship between T, H and E, the statement of Wolff's law at remodeling equilibrium is simply the requirement of the commutativity of the matrix multiplication of the stress tensor and the fabric tensor at remodeling equilibrium, T*H* = H*T*. The asterisk on the stress and fabric tensor indicates their values in remodeling equilibrium. It is shown that the constitutive relation also requires that E*H* = H*E*. Thus, the principal axes of the stress, strain and fabric tensors all coincide at remodeling equilibrium.  相似文献   

9.
Torsional testing of fresh cortical bovine bone showed highly divergent shear moduli at various sites in the middle part of the diaphysis of the right metacarpus. Two hundred samples taken from twenty-five bones were investigated with a free oscillating torsional pendulum to determine the dynamic shear modulus. The results clearly demonstrate the mutual dependence between the shape of the metacarpus and the modulus of the material. On the basis of the analysis of forty-eight samples, a positive correlation was found between the amount of Ca2+ and PO4(3)-ions in the bone and the shear modulus. The hypothesis is put forward that in bone, normal adaptation to increasing stress is obtained by a change in the modulus values, Wolff's law only being operative for extreme cases.  相似文献   

10.
Few have served the Zoological Society of London longer or more faithfully than Alexander Cave who died on 17 May at the great age of 100.
As a Fellow, his record is outstanding: Member of Council, Vice President, Silver Medallist of the Society, Honorary Research Associate; and withal, an unending stream of original papers on various aspects of comparative anatomy. Unending? Well, almost, for he was still being published in his 95th year. Nor should be forgotten the great volume of work that he did in refereeing papers for the Journal of Zoology – an onerous and time-consuming task that he dealt with meticulously.  相似文献   

11.
In August of this year, our regular author V.P. Zinchenko celebrated his sixtieth birthday. The editorial board asked him to give an interview about his view of the contemporary science of psychology. Vladimir Petrovich preferred a series of articles on the eternal problems of developmental psychology. We publish the first of these articles, written in the genre of an essay on scientific themes, in this journal issue. But the editorial board did not abandon its request, and hopes that his interview on the science of psychology will be published in the journal. The editorial board congratulates V.P. Zinchenko on his birthday and wishes him success in his scientific work.  相似文献   

12.
The essay introduces how Paul A. Weiss (1898-1989) analyzed his data on neuronal outgrowth and axonal transport, supported by constriction experiments of thousands of living mature nerve fibers. At the University of Chicago his group measured the steady proximo-distal flow of nerve fibers. To visualize the data he used tissue culturing, light microscopy, radioactive tracers, time-lapse motion pictures and electronmicroscopy. The work resulted in the discovery of fasciculation of outgrowing nerves and a computation of the rate of axonal transport, published in a classical article in 1948. He stated that the outgrowth of nerve fibers occurs from nerve centers in their nucleated cell bodies by fasciculation and protein synthesis. However, at that time one suspected the published microphotograph to be an idealized image and, therefore, did not accept the analysis, or the 'new' knowledge. In the mid 1960s the improved technique of autoradiography confirmed in an indirect way Weiss data and analysis of axonal transport. The objective here is to show (1) how Weiss employed the visibility of micrographs and drawings to corroborate his observations and analysis on axonal dynamics, and (2) to offer some tentative suggestions why his colleagues did not accept the 'neuro-images' as an evidence of new knowledge.  相似文献   

13.
G. O. Sars and the Norwegian Cladocera: a continuing frustration   总被引:4,自引:4,他引:0  
  相似文献   

14.
Stanley L. Welsh 《Brittonia》2005,57(4):301-313
Rupert C. Barneby, his monumental contributions to the taxonomy ofAstragalus and his place among American botanists, is discussed. His twenty contributions in the seriesPugillus Astragalorum spanned fifteen years of his botanical development from an interested naturalist to an accomplished taxonomist in this extremely species-rich genus. Barneby’s work onAstragalus culminated in the 1188 pages of theAtlas of North American Astragalus, which treated of 552 taxa and was published in 1964.  相似文献   

15.
The article presents the analysis of L.S. Vygotsky's works dedicated to the theater arts and is organized according Vygotsky's different life and work stages. Meanwhile special attention is paid to the Gomel period during which a large number of reviews were written by Vygotsky and published in “Nash ponedel'nik” and “Polesskaia pravda” newspapers. Biographical facts are widely used in this analysis and help to clarify Vygotsky's interest in art. It is shown that even at the beginning of his oeuvre, he was interested not only in a range of problems in art, but also psychological problems related to art perception and creativeness. Vygotsky's usage of structural concept ideas about the peculiar properties of literary text composition are also explored. Vygotsky analyzes the socio-psychological mechanisms of theatrical art effect. Furthermore, those areas which are widely used by Vygotsky in determining the characteristics of cast reincarnation are examined. Special emphasis is placed on the different elements of the actor techniques (speech, movement, emotional expression, acting personality and etc.). Materials are widely used in this study and help identify the socio-cultural context that defined Vygotsky's values at different stages of his work, related to his drama criticism and his formation as a professional psychologist.  相似文献   

16.
"Wolff's law" is a concept that has sometimes been misrepresented, and frequently misunderstood, in the anthropological literature. Although it was originally formulated in a strict mathematical sense that has since been discredited, the more general concept of "bone functional adaptation" to mechanical loading (a designation that should probably replace "Wolff's law") is supported by much experimental and observational data. Objections raised to earlier studies of bone functional adaptation have largely been addressed by more recent and better-controlled studies. While the bone morphological response to mechanical strains is reduced in adults relative to juveniles, claims that adult morphology reflects only juvenile loadings are greatly exaggerated. Similarly, while there are important genetic influences on bone development and on the nature of bone's response to mechanical loading, variations in loadings themselves are equally if not more important in determining variations in morphology, especially in comparisons between closely related individuals or species. The correspondence between bone strain patterns and bone structure is variable, depending on skeletal location and the general mechanical environment (e.g., distal vs. proximal limb elements, cursorial vs. noncursorial animals), so that mechanical/behavioral inferences based on structure alone should be limited to corresponding skeletal regions and animals with similar basic mechanical designs. Within such comparisons, traditional geometric parameters (such as second moments of area and section moduli) still give the best available estimates of in vivo mechanical competence. Thus, when employed with appropriate caution, these features may be used to reconstruct mechanical loadings and behavioral differences within and between past populations.  相似文献   

17.
John W. Saunders Jr. is an outstanding contributor to the field of Developmental Biology. His analyses of the apical ectodermal ridge, discovery and study of the zone of polarizing activity, insights into cell death in development, and analytical studies of feather patterns are part of a legacy to developmental biology. The body of his published work remains central to the understanding of limb development and is a major reason for the premiere place that the developmental biology of limbs holds in our research and teaching today. Beyond these things known to nearly everyone, there is John's role as teacher that is equally impressive. His one-on-one style, in small groups or from the podium is engaging, encompassing, and above all else, enthusiastic about the study of the development of living things. His love of developmental biology comes through to students of all ages and is inspirational. And, of course, inimitable charm accompanies the substance of any interaction with John. He still teaches in the Embryology Course at MBL Woods Hole. Recent students say that hearing his lectures and his involvement in the laboratory are highlights of the course. His continued knowledge of science and delight in new advances is a model for students to follow and they recognize it. John Saunders is a scientist and educator par excellence. His contributions have stood the test of time. His personal interactions with colleagues and students have enriched their lives in innumerable ways, large and small. His is a lifetime of outstanding achievements. In this interview, he reflects on his six--going on seven--decades in science and his personal enjoyment of recent advances in Developmental Biology.  相似文献   

18.
Jonathon Howard.     
Jonathon 'Joe' Howard (Fig. 1) is Group Leader and Director at the Max Planck Institute of Molecular Cell Biology and Genetics; he and his research group moved to Dresden, Germany, in July 2001. Howard received his PhD in neurobiology in 1983 from the Australian National University in Canberra. He did postdoctoral research there and also at the University of Bristol, UK, and at the University of California, San Francisco. In 1989, he joined the faculty at the University of Washington. His book "Mechanics of Motor Proteins and the Cytoskeleton" was published earlier this year. [interview by Mari N. Jensen]  相似文献   

19.
The so-called “biometric-Mendelian controversy” has received much attention from science studies scholars. This paper focuses on one scientist involved in this debate, Arthur Dukinfield Darbishire, who performed a series of hybridization experiments with mice beginning in 1901. Previous historical work on Darbishire’s experiments and his later attempt to reconcile Mendelian and biometric views describe Darbishire as eventually being “converted”' to Mendelism. I provide a new analysis of this episode in the context of Darbishire’s experimental results, his underlying epistemology, and his influence on the broader debate surrounding the rediscovery and acceptance of Mendelism. Iinvestigate various historiographical issues raised by this episode in order to reflect on the idea of “conversion” to a scientific theory. Darbishire was an influential figure who resisted strong forces compelling him to convert prematurely due to his requirements that the new theory account for particularly important anomalous facts and answer the most pressing questions in the field. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

20.
On February 20, 1996, a workshop titled "Advances in Sedimentation Velocity Analysis" was held at the Biophysical Society meeting in Baltimore, Maryland, in honor of Professor David Yphantis's 65th birthday. Although he is known more for his work with sedimentation equilibrium, David's work on instrumentation and data analysis is the foundation for many of the recent advances in both equilibrium and velocity sedimentation. Over the years he has trained numerous graduate students, most of whom have gone on to emphasize the use of analytical ultracentrifugation to answer biochemical questions involving macromolecular assembly. His laboratory was one of very few that continued to use and develop analytical ultracentrifugation during its nadir in the 1970s and early 1980s. The rebirth and resurgence of analytical ultracentrifugation owe a great deal to his persistence and enthusiasm. These efforts have borne fruit. In the last five years, through his work at the National Analytical Ultracentrifugation Facility, he has helped train nearly 100 individuals in the delicate art of nonlinear least-squares analysis of equilibrium sedimentation data. Furthermore, the number of researchers using the ultracentrifuge and the number of papers published has skyrocketed in the last few years. This workshop, then, was a way to thank David for his years of devotion to analytical ultracentrifugation.  相似文献   

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