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Lacunae
Kinds of Lacunae Selected AbstractsThe Bone Lining Cell: Its Role in Cleaning Howship's Lacunae and Initiating Bone FormationJOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2002V. Everts Abstract In this study we investigated the role of bone lining cells in the coordination of bone resorption and formation. Ultrastructural analysis of mouse long bones and calvariae revealed that bone lining cells enwrap and subsequently digest collagen fibrils protruding from Howship's lacunae that are left by osteoclasts. By using selective proteinase inhibitors we show that this digestion depends on matrix metalloproteinases and, to some extent, on serine proteinases. Autoradiography revealed that after the bone lining cells have finished cleaning, they deposit a thin layer of a collagenous matrix along the Howship's lacuna, in close association with an osteopontin-rich cement line. Collagenous matrix deposition was detected only in completely cleaned pits. In bone from pycnodysostotic patients and cathepsin K-deficient mice, conditions in which osteoclastic bone matrix digestion is greatly inhibited, bone matrix leftovers proved to be degraded by bone lining cells, thus indicating that the bone lining cell "rescues" bone remodeling in these anomalies. We conclude that removal of bone collagen left by osteoclasts in Howship's lacunae is an obligatory step in the link between bone resorption and formation, and that bone lining cells and matrix metalloproteinases are essential in this process. [source] Intraoperative cytology,Role in bone lesionsDIAGNOSTIC CYTOPATHOLOGY, Issue 9 2010Khaliqur Rahman M.D. Abstract In spite of becoming an integral part of surgical pathology, very few reports are available regarding the utility of intraoperative cytology (IOC) exclusively for bone lesions. This study was undertaken in a view to fill this lacuna. Sixty bone lesions were evaluated intraoperatively with the help of cytology smears prepared by touch, scrape, or crush technique. The diagnosis made on cytological preparation was compared with histopathological diagnosis taking the latter as gold standard. Different parameters like reasons for Intraoperative consultation, best technique for preparation of smear, average time taken to render a diagnosis, and finally the accuracy of IOC was evaluated. Common reasons for the intraoperative consultation were to make or confirm a diagnosis for proper surgical intervention and to evaluate the surgical resection margin. Scrape was found to be the best method for cytological smear preparation. Average time taken to render a diagnosis was 20 minutes. Sensitivity, specificity, and overall diagnostic accuracy was 96.7, 96.6, and 96.6%, respectively. Cytology can play a valuable role in the intraoperative diagnosis of bone lesions. The method is simple, cheap, quick, and has no complication. It should be undertaken routinely, as a rapid intraoperative diagnosis will expedite timely and proper management of the patients, along with early post operative treatment and thus avoid the aggravating delays. Diagn. Cytopathol. 2010;38:639,644. © 2009 Wiley-Liss, Inc. [source] Hydrothermal Synthesis and Structural Characterization of the High-Valent Ruthenium-Containing Polyoxoanion [{PW11O39}2{(HO)RuIV,O,RuIV(OH)}]10,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2008Su-Wen Chen Abstract The high-valent ruthenium-containing [{PW11O39}2{(HO)RuIV,O,RuIV(OH)}]10, anion (1) has been synthesized by hydrothermal reaction and characterized by X-ray diffraction, IR, multinuclear (31P and 183W) NMR spectroscopy andelectrochemistry. Single-crystal analysis was carried outon Rb10[{PW11O39}2{(HO)RuIV,O,RuIV(OH)}]·21H2O, which crystallizes in the monoclinic system, space group P21/n, with a = 11.1912(14), b = 21.9257(12), c = 38.7310(96) Å, , = 94.682(19)°, V = 9472(3) Å3, Z = 4. Polyanion 1 consists of two lacunary [,-PW11O39]7, anions connected by a linear {(HO)Ru,O,Ru(OH)}4+ unit. Each ruthenium ion achieves six-coordination through interaction with two terminal oxo ligands from the lacuna of each [PW11O39]7, anion.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] The rhetoric of public diplomacy and propaganda wars: A view from self-presentation theoryEUROPEAN JOURNAL OF POLITICAL RESEARCH, Issue 5 2007BEN D. MOR Yet public diplomacy and its use in propaganda wars has not been sufficiently theorized, a lacuna that this article seeks to address by means of the social-psychological theory of self-presentation and impression management. The discussion suggests that public diplomacy is a form of self-presentation for social empowerment, in which rhetorical strategies and associated tactics are means of addressing image predicaments in foreign public opinion. The analysis is illustrated by means of the recent Israeli-Palestinian conflict and its presentation in the official websites of the parties. [source] The Burning of Sampati Kuer: Sati and the Politics of Imperialism, Nationalism and Revivalism in 1920s IndiaGENDER & HISTORY, Issue 2 2008Andrea Major Sati, the immolation of a Hindu widow on her husband's funeral pyre, is a rare, but highly controversial practice. It has inspired a surfeit of scholarly studies in the last twenty years, most of which concentrate on one of two main historical sati ,episodes': that of early-colonial Bengal, culminating with the British prohibition of 1829, and that of late twentieth-century Rajasthan, epitomised by the immolation of Roop Kanwar in 1987. Comparatively little detailed historical analysis exists on sati cases between these two events, however, a lacuna this paper seeks to address by exploring British and Indian discourses on sati as they existed in late-colonial India. The paper argues that sati remained a site of ideological and actual confrontation in the early twentieth century, with important implications for ongoing debates about Hindu religion, identity and nation. It focuses on the intersection between various colonial debates and contemporaneous Indian social and political concerns during the controversy surrounding the immolation of Sampati Kuer in Barh, Bihar, in 1927, emphasising resonances with postcolonial interpretations of sati and the dissonance of early nineteenth-century tropes when reproduced in the Patna High Court in 1928. Thus, while Kumkum Sangari and Sudesh Vaid have suggested that ,ad hoc' attempts to piece together a ,modern' narrative of widow immolation began in the 1950s, this paper will suggest that various contemporary discursive formations on sati can be observed in late-colonial India, when discussions of sati became entwined with Indian nationalism and Hindu identity politics and evoked the first organised female response to sati from an emergent women's movement that saw it as an ideological, as well as physical, violation of women. [source] Are Nonresorbing Osteoclasts Sources of Bone Anabolic Activity?,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2007Morten A Karsdal PhD Abstract Some osteopetrotic mutations lead to low resorption, increased numbers of osteoclasts, and increased bone formation, whereas other osteopetrotic mutations lead to low resorption, low numbers of osteoclasts, and decreased bone formation. Elaborating on these findings, we discuss the possibility that osteoclasts are the source of anabolic signals for osteoblasts. In normal healthy individuals, bone formation is coupled to bone resorption in a tight equilibrium. When this delicate balance is disturbed, the net result is pathological situations, such as osteopetrosis or osteoporosis. Human osteopetrosis, caused by mutations in proteins involved in the acidification of the resorption lacuna (ClC-7 or the a3-V-ATPase), is characterized by decreased resorption in face of normal or even increased bone formation. Mouse mutations leading to ablation of osteoclasts (e.g., loss of macrophage-colony stimulating factor [M-CSF] or c- fos) lead to secondary negative effects on bone formation, in contrast to mutations where bone resorption is abrogated with sustained osteoclast numbers, such as the c-src mice. These data indicate a central role for osteoclasts, and not necessarily their resorptive activity, in the control of bone formation. In this review, we consider the balance between bone resorption and bone formation, reviewing novel data that have shown that this principle is more complex than originally thought. We highlight the distinct possibility that osteoclast function can be divided into two more or less separate functions, namely bone resorption and stimulation of bone formation. Finally, we describe the likely possibility that bone resorption can be attenuated pharmacologically without the undesirable reduction in bone formation. [source] The Bone Lining Cell: Its Role in Cleaning Howship's Lacunae and Initiating Bone FormationJOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2002V. Everts Abstract In this study we investigated the role of bone lining cells in the coordination of bone resorption and formation. Ultrastructural analysis of mouse long bones and calvariae revealed that bone lining cells enwrap and subsequently digest collagen fibrils protruding from Howship's lacunae that are left by osteoclasts. By using selective proteinase inhibitors we show that this digestion depends on matrix metalloproteinases and, to some extent, on serine proteinases. Autoradiography revealed that after the bone lining cells have finished cleaning, they deposit a thin layer of a collagenous matrix along the Howship's lacuna, in close association with an osteopontin-rich cement line. Collagenous matrix deposition was detected only in completely cleaned pits. In bone from pycnodysostotic patients and cathepsin K-deficient mice, conditions in which osteoclastic bone matrix digestion is greatly inhibited, bone matrix leftovers proved to be degraded by bone lining cells, thus indicating that the bone lining cell "rescues" bone remodeling in these anomalies. We conclude that removal of bone collagen left by osteoclasts in Howship's lacunae is an obligatory step in the link between bone resorption and formation, and that bone lining cells and matrix metalloproteinases are essential in this process. [source] Free-rider effects of generic advertising: The case of salmonAGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 3 2003Henry W. Kinnucan The free-rider effects of commodity promotion are a neglected issue in the empirical literature. This study addresses the lacuna by considering the salmon promotion program conducted by the Norwegian Seafood Export Council. Specifically, a model of the world salmon market is used to indicate returns to Norwegian producers from NSEC's marketing activities, but also returns to Norway's international competitors. Results suggest program intensification would have a positive effect on total (worldwide) producer surplus in the short run, but the gain's distribution is uneven. Specifically, Norway would receive 23% of the gain compared to 48% for United Kingdom producers. By way of comparison, Norway and UK world trade shares are 47 and 16%, respectively. The disproportionate gains to UK producers are due to a double free ride: from the export tax used to fund the advertising increase, and from the advertising itself. [EconLit citations: L660, Q130, Q170]. © 2003 Wiley Periodicals, Inc. Agribusiness 19: 315,324, 2003. [source] Brain drain in declining organizations: toward a research agendaJOURNAL OF ORGANIZATIONAL BEHAVIOR, Issue 4 2001Zehava Rosenblatt Brain drain (BD) is one of the more detrimental implications of organizational decline and crisis, yet it has only been fleetingly addressed in organization studies. In light of this lacuna, the current paper introduces a conceptual framework of BD during decline. A model featuring both BD antecedents (predictors) and consequences is presented, including an analysis of leavers' behavioral characteristics. The paper offers a set of research propositions and concludes with directions for future study. Copyright © 2001 John Wiley & Sons, Ltd. [source] Mandala of the Self: Embodiment, Practice, and Identity Construction in the Cakrasamvara TraditionJOURNAL OF RELIGIOUS HISTORY, Issue 3 2006DAVID B. GRAY Tantric traditions have often been ignored by scholars studying Asian social history, in part because the structure of traditions, and hence their social impact, have been poorly understood. This paper seeks to remedy this lacuna by exploring in some depth a particular tradition, that centring around the Cakrasamvara Tantra, an Indian Buddhist scripture that became the basis of a popular practice tradition in Nepal and Tibet. Following Charles Taylor and the Comaroffs, I will argue that the Cakrasamvara practice tradition encourages a construction of self-identity based on a rather different set of assumptions than those common in the West, i.e., assumptions concerning the limits and constitution of the self. I will explore the nature of this considerably more expansive and fluid sense of self and its social and historical ramifications, both in the pre-modern and contemporary manifestations of this tradition. [source] The Definition and Measurement of L2 Explicit KnowledgeLANGUAGE LEARNING, Issue 2 2004Rod Ellis A number of theories of second language (L2) acquisition acknowledge a role for explicit L2 knowledge. However, the testing of these theories remains problematic because of the lack of a widely accepted means for measuring L2 explicit knowledge. This article seeks to address this lacuna by examining L2 explicit knowledge from two perspectives. First, it considers explicit knowledge as a construct. How can explicit knowledge be defined? How does it differ from other constructs such as L2 proficiency and language aptitude? Second, the article considers how L2 explicit knowledge can be measured. It critically reviews some of the ways in which explicit knowledge has been operationalized in second language acquisition research and discusses some of the instruments that have been used to measure L2 explicit knowledge. It concludes with some guidelines for investigating explicit knowledge as analyzed knowledge and as metalanguage. [source] Methodological assessment of acid-etching for visualizing the osteocyte lacunar-canalicular networks using scanning electron microscopyMICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2010Daniel J. Kubek Abstract Osteocytes are the most abundant of the bone cells. Each osteocyte is contained within its own lacuna and connected to adjacent osteocytes via fillipodial processes, which form an intricate network of canaliculi within the matrix. Studying this intricate network of cells and their processes is difficult, because it exists embedded within a densely mineralized matrix. Scanning electron microscopy (SEM) has been shown to be a useful tool for visualizing this cellular network, yet the techniques involved for preparing specimens has not been systematically explored. The goal of this study was to investigate how variations in acid-etching, both etching media and etching duration, affect SEM-based visualization of the osteocyte lacunar,canalicular network. Bone samples were embedded in plastic and then acid etched in either 9% (10, 20, 40, and 60 s durations) or 37% (5, 10, and 15 s) phosphoric acid. Specimens were imaged using SEM, and qualitative evaluation of the lacunar,canalicular network was undertaken. Our findings show acid etchingwith a 9% phosphoric acid solution for 20 s provided the most favorable visualization of the osteocyte lacunar,canalicular network. Microsc. Res. Tech., 2010. © 2009 Wiley-Liss, Inc. [source] Intracellular membrane trafficking in bone resorbing osteoclastsMICROSCOPY RESEARCH AND TECHNIQUE, Issue 6 2003Mika Mulari Abstract There is ample evidence now that the two major events in bone resorption, namely dissolution of hydroxyapatite and degradation of the organic matrix, are performed by osteoclasts. The resorption cycle involves several specific cellular activities, where intracellular vesicular trafficking plays a crucial role. Although details of these processes started to open up only recently, it is clear that vesicular trafficking is needed in several specific steps of osteoclast functioning. Several plasma membrane domains are formed during the polarization of the resorbing cells. Multinucleated osteoclasts create a tight sealing to the extracellular matrix as a first indicator of their resorption activity. Initial steps of the sealing zone formation are ,v,3 -integrin mediated, but the final molecular interaction(s) between the plasma membrane and mineralized bone matrix is still unknown. A large number of acidic intracellular vesicles then fuse with the bone-facing plasma membrane to form a ruffled border membrane, which is the actual resorbing organelle. The formation of a ruffled border is regulated by a small GTP-binding protein, rab7, which indicates the late endosomal character of the ruffled border membrane. Details of specific membrane transport processes in the osteoclasts, e.g., the formation of the sealing zone and transcytosis of bone degradation products from the resorption lacuna to the functional secretory domain remain to be clarified. It is tempting to speculate that specific features of vesicular trafficking may offer several potential new targets for drug therapy of bone diseases. Microsc. Res. Tech. 61:496,503, 2003. © 2003 Wiley-Liss, Inc. [source] Revisiting Hrdli,ka and Boas: Asymmetries of Race and Anti-Imperialism in Interwar AnthropologyAMERICAN ANTHROPOLOGIST, Issue 1 2010Robert Oppenheim ABSTRACT, Physical anthropologist Ale, Hrdli,ka is often remembered as an institutional and political opponent of Franz Boas and as an advocate of racial typology against which the Boasian antiracialist position in American anthropology developed. I argue that Hrdli,ka nonetheless also has more subtle lessons to offer about the political limits of Boasian antiracism. Examining Hrdli,ka's engagement with the politics of Europe and East Asia from the 1920s to the 1940s, particularly with the intellectual grounding of Japanese imperialism, I suggest that he was perhaps uniquely cognizant of a "second problem of race in the world",the racist assimilationism of the Japanese empire,vis-à-vis the Boasian grasp of race, rooted in a response to U.S. and Nazi racisms, as a category of invidious difference. Moreover, I contend that the lacuna that Hrdli,ka helps us identify has continued to haunt the discipline at certain key moments of Boasian critique of other ideological forces. [source] CONTRASTING SUBSISTENCE STRATEGIES IN THE EARLY IRON AGE?OXFORD JOURNAL OF ARCHAEOLOGY, Issue 2 2009AND THE THRACIAN PLAIN, BULGARIA, HUNGARY, NEW RESULTS FROM THE ALFÖLD PLAIN Summary. What can students of the past do to establish the predominant land-use and settlement practices of populations who leave little or no artefactual discard as a testament to their lifeways? The traditional answer, especially in Eastern Europe, is to invoke often exogenous nomadic pastoralists whose dwelling in perpetuo mobile was based on yurts, minimal local ceramic production and high curation levels of wooden and metal containers. Such a lacuna of understanding settlement structure and environmental impacts typifies Early Iron Age (henceforth ,EIA') settlements in both Bulgaria and eastern Hungary , a period when the inception of the use of iron in Central and South-East Europe has a profound effect on the flourishing regional bronze industries of the Late Bronze Age (henceforth ,LBA'). The methodological proposal in this paper is the high value of palynological research for subsistence strategies and human impacts in any area with a poor settlement record. This proposal is illustrated by two new lowland pollen diagrams , Ezero, south-east Bulgaria, and Sarló-hát, north-east Hungary , which provide new insights into this research question. In the Thracian valley, there is a disjunction between an area of high arable potential, the small size and short-lived nature of most LBA and EIA settlements and the strong human impact from the LBA and EIA periods in the Ezero diagram. In the Hungarian Plain, the pollen record suggests that, during the LBA,EIA, extensive grazing meadows were established in the alluvial plain, with the inception of woodland clearance on a massive scale from c.800 cal BC, that contradicts the apparent decline in human population in this area. An attempted explanation of these results comprises the exploration of three general positions , the indigenist thesis, the exogenous thesis and the interactionist thesis. Neither of these results fits well with the traditional view of EIA populations as incoming steppe nomadic pastoralists. Instead, this study seeks to explore the tensions between local productivity and the wider exchange networks in which they are entangled. [source] The World Commission on the Social Dimension of Globalization: On the Cross-Border Movement of PeoplePOPULATION AND DEVELOPMENT REVIEW, Issue 2 2004Article first published online: 4 APR 200 The globalization of the world economy can be measured in terms of increases in international trade, greater levels of foreign investment and technology transfers, and the liberalization of financial markets. Accompanying and facilitating these trends have been institutional innovations and reforms, creating regimes under which international economic relationships can be managed and disputes resolved. The role of the World Trade Organization is an evident case in point. The rising scale of international migration can also be seen as a globalizing trend. Here, however, with the exception of the special case of refugees, there is no governance regime in place or in prospect at the international level. Occasional past efforts by UN agencies to stimulate formal discussion of what such a regime might look like have led nowhere: countries are simply unwilling to contemplate any weakening of their sovereign right to control entry. Proposing how to fill this perceived lacuna in the international system is one of the tasks on the agenda of the Global Commission on International Migration. The Commission, an independent body set up in 2003 by a small group of UN member states, plans to present a report to the UN Secretary-General in mid-2005. In the meantime, the subject has been explored by another group,the World Commission on the Social Dimension of Globalization. This commission was set up by the International Labour Office in 2002. It was co-chaired by Tarja Halonen, president of Finland, and Benjamin William Mkapa, president of Tanzania. Its 24 other members included economists (among them Deepak Nayyar, Hernando de Soto, and Joseph Stiglitz), politicians, and business and labor leaders, as well as a number of ex-officio ILO representatives. After several meetings and an extensive series of consultations held during 2002 and 2003, its report, A Fair Globalization: Creating Opportunities for All, was issued in February 2004. The report argues that the benefits of globalization must be more equitably distributed. To this end, the globalizing trends in the world economy should be matched by similar advances in social and political institutions. One of the features of the existing imbalance is that "goods and capital move much more freely across borders than people do." In addition to the many other recommendations the Commission has for what it terms the governance of globalization are proposals on the management of international migration. "Fair rules for trade and capital," the Commission argues, "need to be complemented by fair rules for the movement of people." The long-run objective should be "a multilateral framework for immigration laws and consular practices,,,that would govern cross-border movement of people," paralleling "the multilateral frameworks that already exist, or are currently under discussion, concerning the cross-border movement of goods, services, technology, investment and information." The Commission's thinking on migration is in some respects reminiscent of the views of the ILO's first director, Albert Thomas, in the days of the League of Nations. Writing in 1927, Thomas envisioned, if only as a distant ideal, "some sort of supreme supernational authority which would regulate the distribution of population on rational and impartial lines, by controlling and directing migration movements and deciding on the opening-up or closing of countries to particular streams of immigration." (See the Archives section of PDR 9, no. 4.) The excerpt below consists of §428,§446 of the report, a section titled The cross-border movement of people. [source] Migrant women in male-dominated sectors of the labour market: a research agendaPOPULATION, SPACE AND PLACE (PREVIOUSLY:-INT JOURNAL OF POPULATION GEOGRAPHY), Issue 1 2008Parvati Raghuram Abstract There is a growing literature on female labour migration, but much of this focuses on women who move to work in labour-market sectors where a large proportion of workers are women. This paper argues that there has been much less study of women who migrate to work in male-dominated sectors of the labour market, and explores the nature of this lacuna within research on female migration. It then highlights the increasing presence of women migrants in the ICT sector as one example of an area that has received little study. Finally, the paper explores some reasons why a study of female migrant's experiences in male-dominated sectors of the labour market is important, and what it can add to existing research on female migration more generally. In particular, it urges us to view gender as it intersects and overlaps with other social divisions to produce complex landscapes of female mobility. Copyright © 2007 John Wiley & Sons, Ltd. [source] A Morphological Study of Age Changes in Adult Human Auricular Cartilage With Special Emphasis on Elastic FibersTHE LARYNGOSCOPE, Issue 5 2001Isamu Ito MD Abstract Objective It is well known that the size of the human auricle increases after it has finished development. The reason why the size of the human auricle continues to enlarge until advanced age after reaching adulthood was investigated by observation of the ultrastructure of elastic fibers in human auricular cartilage. Methods A total of 1958 subjects (966 males and 992 females) were classified into 18 age groups from 0 to 5 years up to 85 years and above by 5-year intervals. Ear length, ear width, and length of ear attachment were measured with calipers. Human auricular cartilage was obtained from 26 subjects (16 males and 10 females) aged 14 to 79 years, stained by orcein, and examined by light and electron microscopy. Results Each item of measurement of human auricular size increased significantly with age in both males and females. On morphological examination by light and electron microscopy after orcein staining, elastic fibers in the cartilage were almost homogeneous in diameter and surrounded the cartilage lacuna in bundle-like fashion in young persons, whereas those in elderly persons were heterogeneous in thickness and had many fragments surrounding the territorial matrix. In elderly persons, collagen-like fibers and small vesicles with heterogeneous electron density were frequently observed near elastic bundles around the territorial matrix. Conclusion Structural changes of auricular cartilage associated with morphological age changes of elastic fibers may be one of the causes of expansion of the auricle after reaching adulthood. [source] Development without Institutions: Ersatz Medicine and the Politics of Everyday Life in Rural North IndiaCULTURAL ANTHROPOLOGY, Issue 3 2004Sarah Pinto In north India, unregulated medical practice is considered by many to be a sign of the failure of institutional rationality and "backward" quality of rural life. However, the work of self-made doctors can also be seen to engage key elements of institutional rationality as it is interwoven with the structure and ethos of development. This article explores what these practitioners and their work suggest about the imagination of institutions in rural India and the kinds of power this invokes. Through mimesis of key practices (namely, forms of talk and use of injections), self-made doctors tap into the authority of legitimate institutions to occupy lacunae in state health structures and redress (even as they reproduce) effects of privatization and repeated temporary health measures. At the same time, everyday elements of these practices demonstrate that institutional legitimacy can only be borrowed by those already in positions of authority (on the basis of caste status and political leadership), challenging ideals of equality that underlie health-related development efforts. [source] Hypothermic insult to the periodontium: a model for the study of aseptic tooth resorptionDENTAL TRAUMATOLOGY, Issue 1 2000C. W. Dreyer Abstract , The aim of the current investigation was to define an animal model for the study of hard tissue resorption by examining the responses of the periodontal ligament (PDL) to both single and multiple episodes of hypothermic injury to the crowns of rat teeth. A group of 12 male rats weighing 200,250 g were anesthetized, and pellets of dry ice (CO2) were applied once to the crowns of the right first maxillary molars for continuous periods of 10 or 20 min. Animals were sacrificed at 2, 7, 14 and 28 days and tissues were processed for routine histological examination. A second group of eight animals and a third group of 12 animals were subjected to three applications of dry ice over a period of 1 week and sacrificed at 2 and 14 days respectively after the final application. In addition to thermal insult, the periodontium of teeth from a fourth group of six rats was subjected to mechanical trauma. Examination of the sections from the group undergoing a single freezing episode revealed that, by 1 week, shallow resorption lacunae had appeared on the root surface. These became more extensive after 14 days. At the same time hyaline degeneration was evident in the PDL. Within this group, teeth subjected to the longer 20-min application times generally showed more extensive injuries. By 28 days, evidence of repair was observed with reparative cementum beginning to line the resorption lacunae in the root dentin. Sections from animals subjected to multiple episodes of thermal trauma and those subjected to additional mechanical insult showed more extensive external root resorption than those from single-injury animals. It was concluded that low temperature stimuli applied to the crowns of rat molars were capable of eliciting a sterile degenerative response in the PDL which, in turn, resulted in external root resorption. Furthermore, the degree of this tissue injury was commensurate with the duration and number of exposures to the trauma. The results also indicated that progression of the resorptive process required periodic exposure to the injury, in the absence of which repair to the damaged root occurred. [source] Expression of AMH, SF1, and SOX9 in gonads of genetic female chickens during sex reversal induced by an aromatase inhibitorDEVELOPMENTAL DYNAMICS, Issue 2 2001Séverine Vaillant Abstract Aromatase inhibitors administered prior to histological signs of gonadal sex differentiation can induce sex reversal of genetic female chickens. Under the effects of Fadrozole (CGS 16949A), a nonsteroidal aromatase inhibitor, the right gonad generally becomes a testis, and the left gonad a testis or an ovotestis. We have compared the expression pattern of the genes encoding AMH (the anti-Müllerian hormone), SF1 (steroidogenic factor 1), and SOX9 (a transcription factor related to SRY) in these sex-reversed gonads with that in control testes and ovaries, using in situ hybridization with riboprobes on gonadal sections. In control males, the three genes are expressed in Sertoli cells of testicular cords; however, only SOX9 is male specific, since as observed previously AMH and SF1 but not SOX9 are expressed in the control female gonads. In addition to testicular-like cords, sex-reversed gonads present many lacunae with a composite, thick and flat epithelium. We show that during embryonic and postnatal development, AMH, SF1 and SOX9 are expressed in the epithelium of testicular-like cords and in the thickened part but not in the flattened part of the epithelium of composite lacunae. AMH and SF1 but not SOX9 are expressed in follicular cells of ovotestes. Coexpression of the three genes, of which SOX9 is a specific Sertoli-cell marker, provides strong evidence for the transdifferentiation of ovarian into testicular epithelium in gonads of female chickens treated with Fadrozole. © 2001 Wiley-Liss, Inc. [source] Structural and ultrastructural studies of male reproductive tract and spermatozoa in Xylocopa frontalis (Hymenoptera, Apidae)ACTA ZOOLOGICA, Issue 2 2010B. S. Fiorillo Abstract Fiorillo, B. S., Zama, U., Lino-Neto, J. and Báo, S. N. 2010. Structural and ultrastructural studies of male reproductive tract and spermatozoa in Xylocopa frontalis (Hymenoptera, Apidae). ,Acta Zoologica (Stockholm) 91: 176,183. In Xylocopa frontalis the reproductive tract is composed of testes, deferent ducts, seminal vesicles, accessory glands and an ejaculatory duct. Each testis comprises four testicular tubules in which multiple cysts are present containing approximately 64 spermatozoa per cyst. The seminal vesicle consists of an epithelium, a thick basement lamina and a muscular external sheet. In the luminal region some vesicles can be observed; however, the epithelial cells of the seminal vesicle do not display morphological features associated with secretory functions. The spermatozoa, measuring approximately 260 µm long, are similar to the hymenopteran pattern. The head region consists of an acrosome with an inner perforatorium that penetrates an asymmetrical nuclear tip. The nucleus is linear, electron-dense and its posterior tip projects into the beginning of the axoneme. The centriolar adjunct is asymmetric with many electron-lucent lacunae interspersed throughout. The axoneme has the 9 + 9 + 2 pattern of microtubules and in the posterior region the central microtubules finish first, followed by the doublets and finally the accessory microtubules. The mitochondrial derivatives are asymmetric in both length and diameter with paracrystalline material present only in the larger one. These features may be useful characters for taxonomy and phylogenetic studies. [source] Children and fighting forces: 10 years on from Cape TownDISASTERS, Issue 4 2009Lindsay Stark It is 10 years since the adoption of the Cape Town Principles and Best Practices on the Prevention of Recruitment of Children into the Armed Forces and on Demobilization and Social Reintegration of Child Soldiers in Africa. The field of programming for the reintegration of children associated with armed forces and armed groups has made significant strides in this period. However, important gaps in the knowledge base remain. This paper examines empirical evidence that supports lessons learned from work with children formerly connected with fighting forces. It evaluates what is known, where promising practice exists, and lacunae in five programming areas: psychosocial support and care; community acceptance; education, training and livelihoods; inclusive programming for all war-affected children; and follow-up and monitoring. While the 2007 Paris Commitments to Protect Children from Unlawful Recruitment or Use by Armed Forces or Groups mark an emerging consensus on many issues, there is still a critical need for more systematic studies to develop the evidence base supporting intervention in this area. [source] The bone histology of osteoderms in temnospondyl amphibians and in the chroniosuchian BystrowiellaACTA ZOOLOGICA, Issue 1 2010Florian Witzmann Abstract Witzmann, F. and Soler-Gijón, R. 2010. The bone histology of osteoderms in temnospondyl amphibians and in the chroniosuchian Bystrowiella. ,Acta Zoologica (Stockholm) 91: 96,114 Bone histology of osteoderms in the armoured temnospondyl Peltobatrachus, plagiosaurids (Gerrothorax, Plagiosuchus) and dissorophids (Aspidosaurus, Cacops, Platyhystrix), as well as in the chroniosuchian Bystrowiella, is studied. The massive osteoderms of Peltobatrachus and Gerrothorax consist of homogeneous parallel-fibred bone, whereas in dissorophids, a lightly built, trabecular middle region is mantled by a thin cortex that is composed of a plywood-type structure. In Bystrowiella and Plagiosuchus, the osteoderms consist to a large degree of interwoven primary fibres and have cell lacunae that bear stumpy canaliculi. The differences in the histological structure of dissorophids and plagiosaurids suggest an iterative evolution of osteoderms. Furthermore, histology in Plagiosuchus indicates a metaplastic development of the osteoderms, whereas the osteoderms of Gerrothorax represent periosteal ossifications as in dissorophids. This suggests a convergent origin of osteoderms also within plagiosaurids. The extensive armour in Gerrothorax probably constituted a calcium reservoir, indicated by cyclical resorption events preserved in the external cortex and interpreted as a physiological response to periodic changes in salinity of the aquatic environment. In contrast, the unique osteoderm structure of dissorophids provides maximum stability and minimum bone mass, and is coherent with the interpretation that the osteoderms served to strengthen the vertebral column during terrestrial locomotion. [source] Measuring the national wealth in seventeenth-century EnglandECONOMIC HISTORY REVIEW, Issue 4 2004PAUL SLACK This article discusses William Petty's 1665 estimate of the wealth of England and Wales,the first set of national accounts,and compares it with Gregory King's (1696), which is shown to be heavily influenced by it. There are conclusions about the methodology of the first political arithmeticians, the kinds of national resources which could be measured for the first time in the seventeenth century, and the lacunae which made it likely that Petty and King underestimated per caput and aggregate incomes. An appendix prints a contemporary analysis of hearth tax returns for every county. [source] The microbial community of Vetiver root and its involvement into essential oil biogenesisENVIRONMENTAL MICROBIOLOGY, Issue 10 2008Luigi Del Giudice Summary Vetiver is the only grass cultivated worldwide for the root essential oil, which is a mixture of sesquiterpene alcohols and hydrocarbons, used extensively in perfumery and cosmetics. Light and transmission electron microscopy demonstrated the presence of bacteria in the cortical parenchymatous essential oil-producing cells and in the lysigen lacunae in close association with the essential oil. This finding and the evidence that axenic Vetiver produces in vitro only trace amounts of oil with a strikingly different composition compared with the oils from in vivo Vetiver plants stimulated the hypothesis of an involvement of these bacteria in the oil metabolism. We used culture-based and culture-independent approaches to analyse the microbial community of the Vetiver root. Results demonstrate a broad phylogenetic spectrum of bacteria, including ,-, ,- and ,- Proteobacteria, high-G+C-content Gram-positive bacteria, and microbes belonging to the Fibrobacteres/Acidobacteria group. We isolated root-associated bacteria and showed that most of them are able to grow by using oil sesquiterpenes as a carbon source and to metabolize them releasing into the medium a large number of compounds typically found in commercial Vetiver oils. Several bacteria were also able to induce gene expression of a Vetiver sesquiterpene synthase. These results support the intriguing hypothesis that bacteria may have a role in essential oil biosynthesis opening the possibility to use them to manoeuvre the Vetiver oil molecular structure. [source] Deploying the Classic ,Community Method' in the Social Policy Field: The Example of the Acquired Rights DirectiveEUROPEAN LAW JOURNAL, Issue 2 2009Gavin Barrett The use of the Community method of legislation, in particular the deployment of directives, has for a long time been at the core of EC labour market policy. This article seeks to reflect on the lessons to be learned from the experience of the adoption and operation of one particularly significant directive, namely the Acquired Rights Directive, and on the experience of its transposition in one Member State, Ireland. Among features noted at the EU level are the watering down of the Commission's initial legislative ambitions; the substantial lacunae, failures to address issues and ambiguities incorporated in the text of the directive, the consequent enlarged role for the Court of Justice and the apparent difficulty in changing policy direction in the event of errors being made. As regards the Irish experience of transposing the directive, lessons learnt have included the importance of the means of implementation chosen by the Member State; the obstructive effect which national industrial relations systems may have on the evolution of a common European approach; the significance which attaches to national sanctions and enforcement mechanisms; the importance attaching to the degree of collective organisation in workplaces where the implementing legislation is sought to be relied upon; and the potential which the implementation of a directive has for disruption of the harmony of a national policy approach. Finally, the use of a form of social dialogue in the implementation of employment-related directives in Ireland is also commented upon. [source] Administrative and Court Reform in Central and Eastern EuropeEUROPEAN LAW JOURNAL, Issue 3 2003Frank Emmert Only relatively recently, it was recognised that successful administrative and court reform would be just as necessary in order to achieve the desired goals, namely that the candidates would eventually be able to take on their obligations as new members of the Union. Unfortunately, it has now become evident that it is easier to write new laws than to get them properly applied in every day practice. This article describes a number of cases to illustrate the problem. It shows that administrators and judges in Central and Eastern Europe have significant difficulties with Western working methods, specifically the application of international norms in the national legal order, due process and procedural safeguards, treatment of precedents, resolution of ambiguities and lacunae in the law, etc., which may in turn result in unjust and sometimes absurd application of laws. These difficulties cannot be resolved merely by organising ever more training courses and other theoretical programmes. The author claims that the majority of efforts promoting administrative and court reform applied so far have rendered only meager results. Therefore, additional and more creative measures have to be designed and implemented and have to be continued for years beyond accession of most of these countries to the EU in 2004. Otherwise, rule of law deserving its name will not materialise in the new Member States. The author concludes by offering some ideas based on many years of experience in the region. [source] The origin of the endothelial cells: an evo-devo approach for the invertebrate/vertebrate transition of the circulatory systemEVOLUTION AND DEVELOPMENT, Issue 4 2005R. Muñoz-Chápuli Summary Circulatory systems of vertebrate and invertebrate metazoans are very different. Large vessels of invertebrates are constituted of spaces and lacunae located between the basement membranes of endodermal and mesodermal epithelia, and they lack an endothelial lining. Myoepithelial differentation of the coelomic cells covering hemal spaces is a frequent event, and myoepithelial cells often form microvessels in some large invertebrates. There is no phylogenetic theory about the origin of the endothelial cells in vertebrates. We herein propose that endothelial cells originated from a type of specialized blood cells, called amoebocytes, that adhere to the vascular basement membrane. The transition between amoebocytes and endothelium involved the acquisition of an epithelial phenotype. We suggest that immunological cooperation was the earliest function of these protoendothelial cells. Furthermore, their ability to transiently recover the migratory, invasive phenotype of amoebocytes (i.e., the angiogenic phenotype) allowed for vascular growth from the original visceral areas to the well-developed somatic areas of vertebrates (especially the tail, head, and neural tube). We also hypothesize that pericytes and smooth muscle cells derived from myoepithelial cells detached from the coelomic lining. As the origin of blood cells in invertebrates is probably coelomic, our hypothesis relates the origin of all the elements of the circulatory system with the coelomic wall. We have collected from the literature a number of comparative and developmental data supporting our hypothesis, for example the localization of the vascular endothelial growth factor receptor-2 ortholog in hemocytes of Drosophila or the fact that circulating progenitors can differentiate into endothelial cells even in adult vertebrates. [source] Hearing the Silences in Thomas Bernhard's,Ja: Difference, Narrative, and Lyotard's Concept of the DifferendGERMAN LIFE AND LETTERS, Issue 1 2010Teresa Ludden ABSTRACT This article examines Thomas Bernhard's largely neglected short novel,Ja,(1978) in terms of how silences and textual lacunae function. It uses Lyotard's concept of the differend and Wittgenstein's notion of language-games to analyse the representation of the relationship between the narrator's inner monologue and the female character, ,die Perserin'. It argues that the text alludes to incommensurability between the narrator's idiom and the Persian woman's history and suffering, as well as criticising the imposition of a meta-language and practising an anti-ventriloquism regarding the Persian woman's pain and despair, thus opening the narrative and the text up to its own silences and failings. Dieser Artikel untersucht die Funktion des Schweigens in Thomas Bernhards Roman,Ja,(1978). Er nimmt Jean-François Lyotards Konzept des,Differend,und Ludwig Wittgensteins Theorie der Sprachspiele zu Hilfe, um das erzählerische Monolog und die Darstellung der schweigsamen ,Perserin' zu analysieren. Bernhards Text bezieht sich auf Lücken und Schweigen, indem er nicht für die Perserin spricht sondern auf die Undarstellbarkeit ihres Schmerzes und ihrer Geschichte in der Sprache des Erzählers hinweist. Dadurch thematisiert der Text die Unmöglichkeit einer universalen Metasprache und eine Kritik des Erzählens überhaupt. [source] | ||||||||||||||||||||||||||||||||||