61 resultados para Garment cutting


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This book examines the role of technical standards in the regulation of services at the international level. It brings together scholarship in international political economy, French regulation theory, and economic sociology in order to discuss the following questions: Which services are most likely to be internationalised and what actors are the most concerned by the phenomenon? What is the relationship between the internationalisation of services and their institutional environment? What is more particularly the role of technical standards in delivering and using services? The introductory chapter presents a comprehensive analysis of cutting edge research on these questions. It argues that technical standards shape new forms of collective action and transnational authority. The chapter suggests some hypotheses for a new research agenda.

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RESUME L'architecture nucléaire ainsi que l'ultrastructure des microtubules ont été abondamment étudiées par des méthodes cytochimiques utilisant des échantillons fixés chimiquement, enrobés dans des résines ou fixés à basse température. Les échantillons fixés à basse température pouvant aussi avoir été substitués, déshydratés et enrobés dans des résines pour la plupart hydrophiles. Ici, nous avons étendu ces études en utilisant la microscopie électronique effectuée sur des sections hydratées (CEMOVIS) permettant d'observer les échantillons dans un état le plus proche de leur état natif. De plus, nous avons effectué de la tomographie électronique sur des sections hydratées (TOVIS) afin d'obtenir une vision tridimensionnelle de : 1) la périphérie du noyau et de la région périchromatinienne et 2) de la lumière des microtubules. Concernant l'architecture nucléaire Nos observations montrent que le nucléole et la chromatine condensée sont facilement visualisés grâce à la texture spécifique qu'ils arborent. Au contraire, la visualisation de domaines nucléaires importants et spécialement ceux qui contiennent des ribonucléoprotéines, est rendue difficile, à cause du faible contraste qui caractérise l'espace interchromatinien. Ceci est essentiellement dû à la quantité d'information présente dans le volume de la section qui semble être superposée, lorsque observée sur des micrographies en deux dimensions. La tomographie nous a permis de mieux visualiser les différentes régions du noyau. Les mottes de chromatine condensée sont décorées à leur périphérie (région périchromatinienne), par nombre de fibrilles et granules. Des tunnels d'espace interchromatinien sont occasionnellement observés en train de traverser des régions de chromatine condensée favorisant l'accès aux pores nucléaires. Enfin, nous avons pu, au niveau d'un pore unique, observer la plupart des structures caractéristiques du complexe de pore nucléaire. Concernant l'ultrastructure des microtubules: Nous avons démontré que la polarité d'un microtubule observé in situ en section transversale, par CEMOVIS, est directement déduite de l'observation de la chiralité de ses protofilaments. Cette chiralité, a été établie précédemment comme étant liée à la morphologie des sous unités de tubuline. La tomographie électronique effectuée sur des sections hydratées, nous a permis d'observer les microtubules dans leur contexte cellulaire avec une résolution suffisante pour visualiser des détails moléculaires, comme les monomères de tubuline. Ainsi, des molécules n'ayant pas encore été caractérisées, ont été observées dans la lumière des microtubules. Ces observations ont été effectuées autant sur des cellules observées en coupe par CEMOVIS que sur des cellules congelées dans leur totalité par immersion dans un bain d'éthane liquide. Enfin, nous avons montré que les microtubules étaient aussi de formidables objets, permettant une meilleure compréhension des artéfacts de coupe occasionnés lors de la préparation des échantillons par CEMOVIS. Les buts des études qui seront menées â la suite de ce travail seront de 1) essayer de localiser des domaines nucléaires spécifiques par des approches cytochimiques avant la congélation des cellules. 2) Appliquer des méthodes de moyennage afin d'obtenir un modèle tridimensionnel de la structure du complexe de pore nucléaire dans son contexte cellulaire. 3) Utiliser des approches biochimiques afin de déterminer la nature exacte des particules qui se trouvent dans la lumière des microtubules. ABSTRACT Nuclear architecture as well as microtubule ultrastructure have been extensively investigated by means of different methods of ultrastructural cytochemistry using chemically fixed and resin embedded samples or following cryofixation, cryosubstitution and embedding into various, especially partially hydrophilic resins. Here, we extend these studies using cryoelectron microscopy of vitreous sections (CEMOVIS) which allows one to observe the specimen as close as possible to its native state. Furthermore, we applied cryoelectron tomography of vitreous sections (TOVIS) in order to obtain athree-dimensional view of: 1) the nuclear periphery, and of the perichromatin region, and 2) the microtubule lumen. Concerning the nuclear architecture: Our observations show that nucleoli and condensed chromatin are well recognisable due to their specific texture. Conversely, the visualisation of other important nuclear domains, especially those containing ribonucleoproteins, is seriously hampered by a generally low contrast of the interchromatin region. This is mainly due to the plethora of information superposed in the volume of the section observed on two-dimensional micrographs. Cryoelectron tomography allowed us to better visualise nuclear regions. Condensed chromatin clumps are decorated on their periphery, the perichromatin region, by numerous fibrils and granules. Tunnels of interchromatin space can occasionally be found as crossing condensed chromatin regions, thus, allowing the access to nuclear pores. Finally, we were able to use TOVIS to directly distinguish most of the nuclear pore complex structures, at the level of a single pore. Concerning the microtubule ultrastructure: We have demonstrated that the polarity of across-sectioned microtubule observed in situ by CEMOVIS wás directly deducible from the visualisation of the tubulin protofiíaments' chirality. This chirality has been established before as related to the shape. of the tubulin subunits. Cryoelectron tomography allowed us to observe microtubules in their cellular context at a resolution sufficient to resolve molecular details such as their tubulin monomers. In this way, uncharacterized molecules were visualised in the microtubule lumen. These observations were made either on samples prepared by CEMOVIS or plunge freezing of whole cells. Finally, we have shown that microtubules are also relevant objects for the understanding of cutting artefacts, when performing CEMOVIS. The goals of our further studies will be to: 1) try to speciifically target different nuclear domains by cytochemical approaches in situ, prior to cryofixation. 2) Apply averaging methods in order to obtain a three-dimensional model of the nuclear pore complex at work, in its cellular context. 3) Use biochemical analysis combined in a second time to immunocytochemical approaches, to determine the exact nature of the microtubule's luminal particles.

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With the widespread availability of high-throughput sequencing technologies, sequencing projects have become pervasive in the molecular life sciences. The huge bulk of data generated daily must be analyzed further by biologists with skills in bioinformatics and by "embedded bioinformaticians," i.e., bioinformaticians integrated in wet lab research groups. Thus, students interested in molecular life sciences must be trained in the main steps of genomics: sequencing, assembly, annotation and analysis. To reach that goal, a practical course has been set up for master students at the University of Lausanne: the "Sequence a genome" class. At the beginning of the academic year, a few bacterial species whose genome is unknown are provided to the students, who sequence and assemble the genome(s) and perform manual annotation. Here, we report the progress of the first class from September 2010 to June 2011 and the results obtained by seven master students who specifically assembled and annotated the genome of Estrella lausannensis, an obligate intracellular bacterium related to Chlamydia. The draft genome of Estrella is composed of 29 scaffolds encompassing 2,819,825 bp that encode for 2233 putative proteins. Estrella also possesses a 9136 bp plasmid that encodes for 14 genes, among which we found an integrase and a toxin/antitoxin module. Like all other members of the Chlamydiales order, Estrella possesses a highly conserved type III secretion system, considered as a key virulence factor. The annotation of the Estrella genome also allowed the characterization of the metabolic abilities of this strictly intracellular bacterium. Altogether, the students provided the scientific community with the Estrella genome sequence and a preliminary understanding of the biology of this recently-discovered bacterial genus, while learning to use cutting-edge technologies for sequencing and to perform bioinformatics analyses.

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Mountains and mountain societies provide a wide range of goods and services to humanity, but they are particularly sensitive to the effects of global environmental change. Thus, the definition of appropriate management regimes that maintain the multiple functions of mountain regions in a time of greatly changing climatic, economic, and societal drivers constitutes a significant challenge. Management decisions must be based on a sound understanding of the future dynamics of these systems. The present article reviews the elements required for an integrated effort to project the impacts of global change on mountain regions, and recommends tools that can be used at 3 scientific levels (essential, improved, and optimum). The proposed strategy is evaluated with respect to UNESCO's network of Mountain Biosphere Reserves (MBRs), with the intention of implementing it in other mountain regions as well. First, methods for generating scenarios of key drivers of global change are reviewed, including land use/land cover and climate change. This is followed by a brief review of the models available for projecting the impacts of these scenarios on (1) cryospheric systems, (2) ecosystem structure and diversity, and (3) ecosystem functions such as carbon and water relations. Finally, the cross-cutting role of remote sensing techniques is evaluated with respect to both monitoring and modeling efforts. We conclude that a broad range of techniques is available for both scenario generation and impact assessments, many of which can be implemented without much capacity building across many or even most MBRs. However, to foster implementation of the proposed strategy, further efforts are required to establish partnerships between scientists and resource managers in mountain areas.

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Managing Football is the first book to directly respond to the rapid managerial, commercial and global development of the sport and offers a thorough analysis of how the football industry can meet the challenges that flow from these developments. Expertly edited by two well known specialists in football business management, it draws together the work of a world-class contributor team to form a comprehensive analysis of the most important issues facing the managers of football businesses across the world. The cutting edge analysis examines all the important business challenges in the football industry and the management of football businesses and covers all of the key football markets including England, Spain, France, Italy, Germany, Australia, North America, China, South Africa, South Korea, the Netherlands & Belgium, and Mexico. Managing Football is simply a must-read for anyone studying or working in football business management and is set to be an important landmark in this rapidly moving and globally expansive field.

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The detailed geological mapping and structural study of a complete transect across the northwestern Himalaya allow to describe the tectonic evolution of the north Indian continental margin during the Tethys ocean opening and the Himalayan Orogeny. The Late Paleozoic Tethys rifting is associated with several tectonomagmatic events. In Upper Lahul and SE Zanskar, this extensional phase is recorded by Lower Carboniferous synsedimentary transtensional faults, a Lower Permian stratigraphic unconformity, a Lower Permian granitic intrusion and middle Permian basaltic extrusions (Panjal Traps). In eastern Ladakh, a Permian listric normal fault is also related to this phase. The scarcity of synsedimentary faults and the gradual increase of the Permian syn-rift sediment thickness towards the NE suggest a flexural type margin. The collision of India and Asia is characterized by a succession of contrasting orogenic phases. South of the Suture Zone, the initiation of the SW vergent Nyimaling-Tsarap Nappe corresponds to an early phase of continental underthrusting. To the S, in Lahul, an opposite underthrusting within the Indian plate is recorded by the NE vergent Tandi Syncline. This structure is associated with the newly defined Shikar Beh Nappe, now partly eroded, which is responsible for the high grade (amphibolite facies) regional metamorphism of South Lahul. The main thrusting of the Nyimaling-Tsarap Nappe followed the formation of the Shikar Beh Nappe. The Nyimaling-Tsarap Nappe developed by ductile shear of the upper part of the subducted Indian continental margin and is responsible for the progressive regional metamorphism of SE Zanskar, reaching amphibolite facies below the frontal part of the nappe, near Sarchu. In Upper Lahul, the frontal parts of the Nyimaling-Tsarap and Shikar Beh nappes are separated by a zone of low grade metamorphic rocks (pumpellyite-actinolite facies to lower greenschist facies). At high structural level, the Nyimaling-Tsarap Nappe is characterized by imbricate structures, which grade into a large ductile shear zone with depth. The related crustal shortening is about 87 km. The root zone and the frontal part of this nappe have been subsequently affected by two zones of dextral transpression and underthrusting: the Nyimaling Shear Zone and the Sarchu Shear Zone. These shear zones are interpreted as consequences of the counterclockwise rotation of the continental underthrusting direction of India relative to Asia, which occurred some 45 and 36 Ma ago, according to plate tectonic models. Later, a phase of NE vergent `'backfolding'' developed on these two zones of dextral transpression, creating isoclinal folds in SE Zanskar and more open folds in the Nyimaling Dome and in the Indus Molasse sediments. During a late stage of the Himalayan Orogeny, the frontal part of the Nyimaling-Tsarap Nappe underwent an extension of about 15 km. This phase is represented by two types of structures, responsible for the tectonic unroofing of the amphibolite facies rocks of the Sarchu area: the Sarchu high angle Normal Fault, cutting a first set of low angle normal faults, which have been created by reactivation of older thrust planes related to the Nyimaling-Tsarap Nappe.

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The processing of biological motion is a critical, everyday task performed with remarkable efficiency by human sensory systems. Interest in this ability has focused to a large extent on biological motion processing in the visual modality (see, for example, Cutting, J. E., Moore, C., & Morrison, R. (1988). Masking the motions of human gait. Perception and Psychophysics, 44(4), 339-347). In naturalistic settings, however, it is often the case that biological motion is defined by input to more than one sensory modality. For this reason, here in a series of experiments we investigate behavioural correlates of multisensory, in particular audiovisual, integration in the processing of biological motion cues. More specifically, using a new psychophysical paradigm we investigate the effect of suprathreshold auditory motion on perceptions of visually defined biological motion. Unlike data from previous studies investigating audiovisual integration in linear motion processing [Meyer, G. F. & Wuerger, S. M. (2001). Cross-modal integration of auditory and visual motion signals. Neuroreport, 12(11), 2557-2560; Wuerger, S. M., Hofbauer, M., & Meyer, G. F. (2003). The integration of auditory and motion signals at threshold. Perception and Psychophysics, 65(8), 1188-1196; Alais, D. & Burr, D. (2004). No direction-specific bimodal facilitation for audiovisual motion detection. Cognitive Brain Research, 19, 185-194], we report the existence of direction-selective effects: relative to control (stationary) auditory conditions, auditory motion in the same direction as the visually defined biological motion target increased its detectability, whereas auditory motion in the opposite direction had the inverse effect. Our data suggest these effects do not arise through general shifts in visuo-spatial attention, but instead are a consequence of motion-sensitive, direction-tuned integration mechanisms that are, if not unique to biological visual motion, at least not common to all types of visual motion. Based on these data and evidence from neurophysiological and neuroimaging studies we discuss the neural mechanisms likely to underlie this effect.

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Data mining can be defined as the extraction of previously unknown and potentially useful information from large datasets. The main principle is to devise computer programs that run through databases and automatically seek deterministic patterns. It is applied in different fields of application, e.g., remote sensing, biometry, speech recognition, but has seldom been applied to forensic case data. The intrinsic difficulty related to the use of such data lies in its heterogeneity, which comes from the many different sources of information. The aim of this study is to highlight potential uses of pattern recognition that would provide relevant results from a criminal intelligence point of view. The role of data mining within a global crime analysis methodology is to detect all types of structures in a dataset. Once filtered and interpreted, those structures can point to previously unseen criminal activities. The interpretation of patterns for intelligence purposes is the final stage of the process. It allows the researcher to validate the whole methodology and to refine each step if necessary. An application to cutting agents found in illicit drug seizures was performed. A combinatorial approach was done, using the presence and the absence of products. Methods coming from the graph theory field were used to extract patterns in data constituted by links between products and place and date of seizure. A data mining process completed using graphing techniques is called ``graph mining''. Patterns were detected that had to be interpreted and compared with preliminary knowledge to establish their relevancy. The illicit drug profiling process is actually an intelligence process that uses preliminary illicit drug classes to classify new samples. Methods proposed in this study could be used \textit{a priori} to compare structures from preliminary and post-detection patterns. This new knowledge of a repeated structure may provide valuable complementary information to profiling and become a source of intelligence.

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Aujourd'hui, la construction sociale de la ménopause intéresse de nombreux chercheurs en sciences sociales. Cependant, la façon dont les femmes vivent ou se représentent cet événement reste peu documentée. L'objectif de cette thèse est donc d'approfondir la compréhension de l'expérience de la ménopause en accordant une place primordiale aux discours et aux pratiques des femmes elles-mêmes. En s'appuyant sur une recherche ethnographique en Suisse romande et au Centre-Cameroun, cette étude parcourt différentes dimensions de l'expérience de la ménopause (représentations, vécus, pratiques de gestion) qui, corrélées les unes aux autres, forment un tout. Au-delà des divergences que l'on peut observer au niveau culturel, de la situation économique et sociale des femmes, des systèmes de santé et du statut occupé par la ménopause dans les deux pays, les résultats de ce travail montrent que les expériences de la ménopause chez les Suissesses et les Camerounaises interviewées ne peuvent pas simplement être classifiées de manière binaire ou dichotomique. Dans chacun des contextes, ces expériences sont plurielles et dépendent de plusieurs facteurs. D'une part, elles découlent d'une observation empirique de la part de ces femmes elles-mêmes et de leurs interactions avec différents acteurs dont les médias (particulièrement en Suisse), les pairs, les proches et les professionnels de la santé. D'autre part, elles sont influencées par de nombreuses variables parmi lesquelles le contexte économique, socioculturel, familial et conjugal, le statut professionnel, la prévalence des troubles ressentis et le statut ménopausique de ces femmes. Mais, ces facteurs ne sont pas hiérarchisés puisqu'ils agissent différemment pour chacune d'entre elles. Dès lors, s'il apparaît que les expériences ménopausiques n'échappent point aux déterminations sociales, il n'en demeure pas moins qu'elles relèvent aussi des capacités réflexives des femmes, les conduites sociales n'étant pas réductibles à des applications des codes intériorisés. Au fil du travail, la médicalisation de la ménopause, bien qu'existant à des degrés variables entre la Suisse et le Cameroun, a émergé comme une problématique transversale. Interrogeant les logiques qui la sous-tendent, cette étude se propose d'analyser le rôle que jouent les femmes elles-mêmes dans ce processus. - Today, the social construction of the menopause is of great interest for many researchers in social sciences. Neverthless, the way of living or of representing this event is still little documented. The aim of this thesis is to study thoroughly the understanding of menopausal experience through the discourses and practices of women themselves. Based on an ethnograph ic research, in French-speaking Switzerland and in Centre-Cameroon, this study looks at different dimensions of menopausal experience (representations, real-life experiences, pratices) that, connected to each other, form a whole. Inspite of the cultural, economic, social, health systems and menopausal status differences between these two countries, the results of this thesis show that menopausal experiences among the Swiss and the Cameroonians interviewee can not simply be classified in two dichotomous groups. In each context, those experiences are plural and depend on several factors. On the one hand, they arise from women's own empirical observations and from their interactions with several actors like the media (especially in Switzerland), the peers, the people closest to them and health professionals. On the other hand, they are influenced by many elements such as the economical, sociocultural, family and marital context, the professional status, the prevalence of felt disorders and the menopausal status of those women. But, these factors are not hierarchical beacause they operate differently for each person. Accordingly, if menopausal experiences don't escape from social determinism, nonetheless they also depend on the reflexive capacities of women beacause social conducts can not be reduced to the application of interiorised codes. Through this work, the médicalisation of the menopause, even though varying between Switzerland and Cameroon, comes to light as a cross-cutting problematic. Questioning its underlying logic, this study proposes to analyse the role that women themselves play in this process.

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Calceology is the study of recovered archaeological leather footwear and is comprised of conservation, documentation and identification of leather shoe components and shoe styles. Recovered leather shoes are complex artefacts that present technical, stylistic and personal information about the culture and people that used them. The current method in calceological research for typology and chronology is by comparison with parallel examples, though its use poses problems by an absence of basic definitions and the lack of a taxonomic hierarchy. The research findings of the primary cutting patterns, used for making all leather footwear, are integrated with the named style method and the Goubitz notation, resulting in a combined methodology as a basis for typological organisation for recovered footwear and a chronology for named shoe styles. The history of calceological research is examined in chapter two and is accompanied by a review of methodological problems as seen in the literature. Through the examination of various documentation and research techniques used during the history of calceological studies, the reasons why a standard typology and methodology failed to develop are investigated. The variety and continual invention of a new research method for each publication of a recovered leather assemblage hindered the development of a single standard methodology. Chapter three covers the initial research with the database through which the primary cutting patterns were identified and the named styles were defined. The chronological span of each named style was established through iterative cross-site sedation and named style comparisons. The technical interpretation of the primary cutting patterns' consistent use is due to constraints imposed by the leather and the forms needed to cover the foot. Basic parts of the shoe patterns and the foot are defined, plus terms provided for identifying the key points for pattern making. Chapter four presents the seventeen primary cutting patterns and their sub-types, these are divided into three main groups: six integral soled patterns, four hybrid soled patterns and seven separately soled patterns. Descriptions of the letter codes, pattern layout, construction principle, closing seam placement and list of sub-types are included in the descriptions of each primary cutting pattern. The named shoe styles and their relative chronology are presented in chapter five. Nomenclature for the named styles is based on the find location of the first published example plus the primary cutting pattern code letter. The named styles are presented in chronological order from Prehistory through to the late 16th century. Short descriptions of the named styles are given and illustrated with examples of recovered archaeological leather footwear, reconstructions of archaeological shoes and iconographical sources. Chapter six presents documentation of recovered archaeological leather using the Goubitz notation, an inventory and description of style elements and fastening methods used for defining named shoe styles, technical information about sole/upper constructions and the consequences created by the use of lasts and sewing forms for style identification and fastening placement in relation to the instep point. The chapter concludes with further technical information about the implications for researchers about shoemaking, pattern making and reconstructive archaeology. The conclusion restates the original research question of why a group of primary cutting patterns appear to have been used consistently throughout the European archaeological record. The quantitative and qualitative results from the database show the use of these patterns but it is the properties of the leather that imposes the use of the primary cutting patterns. The combined methodology of primary pattern identification, named style and artefact registration provides a framework for calceological research.

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This paper outlines recent conceptual and methodological developments in the assessment of triadic and family group process during infancy and toddlerhood. Foundations of the emerging family group process are identified, and conditions specific to the assessment of the family during the early phases of family formation are summarized. Both microanalytic and global approaches to evaluating mother-father-child interactions are discussed. We highlight both similarities and differences in the strategies and methods employed by several different investigators who have been studying the group dynamics of families with infant and toddler children, and underscore several important family patterns and emerging themes that appear to be cutting across these different methods and measurement strategies. Preliminary evidence for the validity and clinical significance of family-level assessments is summarized, and directions currently being pursued by researchers engaged in studies of the family triad are outlined. We close by identifying several conceptual and clinical issues that remain to be addressed by subsequent work.

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The pool of mature T cells comprises a heterogeneous mixture of naive and memory CD4(+) and CD8(+) cells. These cells are long lived at a population level but differ markedly in their relative rates of turnover and survival. Here, we review how contact with exogenous stimuli, notably self MHC ligands and various gamma(c) cytokines, plays a decisive role in controlling normal T cell homeostasis.

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Three-dimensional (3D) planning is becoming a more commonly used tool in maxillofacial surgery. At first used only virtually, 3D planning now also enables the creation of useful intraoperative aids such as cutting guides, which decrease the operative difficulty. In our center, we have used 3D planning in various domains of facial surgery and have investigated the advantages of this technique. We have also addressed the difficulties associated with its use. 3D planning increases the accuracy of reconstructive surgery, decreases operating time, whilst maintaining excellent esthetic results. However, its use is restricted to osseous reconstruction at this stage and once planning has been undertaken, it cannot be reversed or altered intraoperatively. Despite the attractive nature of this new tool, its uses and practicalities must be further evaluated. In particular, cost-effectiveness, hospital stay, and patient perceived benefits must be assessed.

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Visualization of the vascular systems of organs or of small animals is important for an assessment of basic physiological conditions, especially in studies that involve genetically manipulated mice. For a detailed morphological analysis of the vascular tree, it is necessary to demonstrate the system in its entirety. In this study, we present a new lipophilic contrast agent, Angiofil, for performing postmortem microangiography by using microcomputed tomography. The new contrast agent was tested in 10 wild-type mice. Imaging of the vascular system revealed vessels down to the caliber of capillaries, and the digital three-dimensional data obtained from the scans allowed for virtual cutting, amplification, and scaling without destroying the sample. By use of computer software, parameters such as vessel length and caliber could be quantified and remapped by color coding onto the surface of the vascular system. The liquid Angiofil is easy to handle and highly radio-opaque. Because of its lipophilic abilities, it is retained intravascularly, hence it facilitates virtual vessel segmentation, and yields an enduring signal which is advantageous during repetitive investigations, or if samples need to be transported from the site of preparation to the place of actual analysis, respectively. These characteristics make Angiofil a promising novel contrast agent; when combined with microcomputed tomography, it has the potential to turn into a powerful method for rapid vascular phenotyping.

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The distribution of red, iron-containing enamel in the teeth of shrews (Soricidae) was investigated by optical and scanning electron microscopy in order to determine its function. Transverse and longitudinal sections of crania with mandibles in occlusion demonstrate that the red enamel in molars is restricted to corresponding wear facets (lingual side of upper molars, buccal side of lower molars). The projecting, scissor-like cutting edges produced by wear are composed of iron-containing enamel which wears away more slowly than adjacent white enamel. Therefore, this red enamel must be more resistant to abrasion and serves to prolong the usefullness of cutting edges. Finally, two alternative hypotheses are proposed to explain the secondary loss of the red, iron-bearing enamel in members of the Soricidae which lack this material.