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Several Stages (several + stage)
Selected AbstractsTranspressional tectonics of the Mineoka Ophiolite Belt in a trench,trench,trench-type triple junction, Boso Peninsula, JapanISLAND ARC, Issue 4 2005Ryota Mori Abstract Structures developed in metamorphic and plutonic blocks that occur as knockers in the Mineoka Ophiolite Belt in the Boso Peninsula, central Japan, were analyzed. The aim was to understand the incorporation processes of blocks of metamorphic and plutonic rocks with an arc signature into the serpentinite mélange of the Mineoka Ophiolite Belt in relation to changes in metamorphic conditions during emplacement. Several stages of deformation during retrogressive metamorphism were identified: the first faulting stage had two substage shearing events (mylonitization) under ductile conditions inside the crystalline blocks in relatively deeper levels; and the second stage had brittle faulting and brecciation along the boundaries between the host serpentinite bodies in relatively shallower levels (zeolite facies). The first deformation occurred during uplift before emplacement. The blocks were intensively sheared by the first deformation event, and developed numerous shear planes with spacing of a few centimeters. The displacement and width of each shear plane were a few centimeters and a few millimeters, respectively, at most. In contrast, the fault zone of the second shearing stage reached a few meters in width and developed during emplacement of the Mineoka Ophiolite. Both stages occurred under a right-lateral transpressional regime, in which thrust-faulting was associated with strike-slip faulting. Such displacement on an outcrop scale is consistent with the present tectonics of the Mineoka Belt. This implies that the same tectonic stress has been operating in the Boso trench,trench,trench-type triple junction area in the northwest corner of the Pacific since the emplacement of the Mineoka Ophiolite. The Mineoka Ophiolite Belt must have worked as a forearc sliver fault during the formation of a Neogene accretionary prism further south. [source] Waiting for scheduled services in Canada: development of priority-setting scoring systemsJOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 1 2003T. W. Noseworthy MD MSc MPH FRCPC FACP FCCP FCCM CHE Abstract Rationale, aims and objectives An Achilles' heel of Canadian Medicare is long waits for elective services. The Western Canada Waiting List (WCWL) project is a collaboration of 19 partner organizations committed to addressing this issue and influencing the way waiting lists are structured and managed. The focus of the WCWL project has been to develop and refine practical tools for prioritizing patients on scheduled waiting lists. Methods Scoring tools for priority setting were developed through extensive clinical input and highly iterative exchange by clinical panels constituted in five clinical areas: cataract surgery; general surgery procedures; hip and knee replacement; magnetic resonance imaging (MRI) scanning, and children's mental health. Several stages of empirical work were conducted to formulate and refine criteria and to assess and improve their reliability and validity. To assess the acceptability and usability of the priority-setting tools and to identify issues pertaining to implementation, key personnel in the seven regional health authorities (RHAs) participated in structured interviews. Public opinion focus groups were conducted in the seven western cities. Results Point-count scoring systems were constructed in each of the clinical areas. Participating clinicians confirmed that the tools offered face validity and that the scoring systems appeared practical for implementation and use in clinical settings. Reliability was strongest for the general surgery and hip and knee criteria, and weakest for the diagnostic MRI criteria. Public opinion focus groups endorsed wholeheartedly the application of point-count priority measures. Regional health authorities were generally supportive, though cautiously optimistic towards implementation. Conclusions While the WCWL project has not ,solved' the problem of waiting lists and times, having a standardized, reliable means of assigning priority for services is an important step towards improved management in Canada and elsewhere. [source] POTS AND PITS: DRINKING AND DEPOSITION IN LATE IRON AGE SOUTH-EAST BRITAINOXFORD JOURNAL OF ARCHAEOLOGY, Issue 2 2005MARTIN PITTS Summary. This paper considers the role of pottery in the Late Iron Age to Roman transition in south-east Britain. Traditional concern with the significance of Continental imports is rejected in favour of a more holistic and bottom-up approach giving equal emphasis to locally made forms and imports in complete assemblages. Several stages of inter-site correspondence analysis are conducted on a range of sites and assemblages in the region. Patterning pertaining to the use and deposition of both imported and local pottery vessels can be seen to contradict simplistic models for ,Romanization before conquest'. The main conclusions include evidence for the selective disposal of drinking vessels and table wares in pits, the likely widespread consumption of beer as opposed to wine, and the implied importance of indigenous social practices such as feasting and communal drinking. [source] Information needs and prostate cancer: the development of a systematic means of identificationBJU INTERNATIONAL, Issue 1 2004Jeremy Dale OBJECTIVE To design, from first principles, a valid and reliable scale for assessing the importance of specific items of information needed by patients with prostate cancer that would be straightforward to use in clinical settings, as despite its prevalence, there is little research focusing specifically on the information needs associated with prostate cancer. PATIENTS AND METHODS Several stages of consultation and modification were used to inform the development of a scale which was then piloted on 96 patients with prostate cancer. Respondents were asked to rate the importance they placed on a range of prostate cancer-related topics of information, and the extent to which they felt these information needs had been met. The construct and content validity of the instrument were established and an exploratory factor analysis used to guide restructuring of the tool. Internal consistency/reliability was calculated using Cronbach's ,. RESULTS Using the scale showed that men with prostate cancer placed considerable importance on a broad range of information needs, most of which had been inadequately met. Age had a significant influence on the overall importance attributed to information, with younger patients having more need for information. The construct and content validity of the instrument were established. The factor analysis revealed four discrete factors which together explained >,68% of the variance, termed ,basics of prostate cancer care', ,disease management', ,physical well-being' and ,self-help'. Internal consistency/reliability was satisfactory (, = 0.91). CONCLUSIONS The basis of a tool capable of ascertaining the information needs of patients with prostate cancer was developed; it may offer clinicians a valid means of ascertaining information preferences and hence potentially enhance the quality of service provided. Further research is now required to refine the tool and test the effect of its longitudinal use in clinical practice on patient satisfaction and outcome. [source] Development and fine structure of the yolk nucleus of previtellogenic oocytes in the medaka Oryzias latipesDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 6 2000Hirokuni Kobayashi The development and fine structure of yolk nuclei in the cytoplasm of previtellogenic oocytes were examined by electron microscopy during several stages of oogenesis in the medaka, Oryzias latipes. Shortly after oogenesis starts, oocytes 20,30 ,m in diameter have much electron-dense (basophilic) cytoplasm, within which a continuous or discontinuous, irregular ring-shaped lower electron-dense area of flocculent appearance (LF) begins to emerge around the nucleus. The yolk nucleus is first recognized within an LF area as a few fragments of dense granular thread measuring 20,25 nm in width. The threads consist of two rows of very dense granules resembling ribosomes or ribonucleoprotein (RNP)-like particles in size and electron density. These thread-like fragments gradually increase in number and length until they assemble into a compact, spherical mass of complicated networks. Analysis of serial sections suggests that the yolk nucleus is a complicated mass of numerous, small deformed vacuoles composed of a single lamella with double layers of ribosomes or RNP-like granules, rather than a mass of granular threads. When oocytes develop to greater than 100 ,m in diameter, the yolk nucleus begins to fragment before dispersing throughout the surrounding cytoplasm, concomitantly with the disappearance of LF areas. At this stage of oogenesis, a restricted region of the granulosa cell layer adjacent to the yolk nucleus becomes somewhat columnar in morphology, fixing the vegetal pole region of the oocyte. [source] Changing role of in vivo models in columnar-lined lower esophagusDISEASES OF THE ESOPHAGUS, Issue 4 2002Y. Koak SUMMARY. Columnar-lined lower esophagus (CLE) or Barrett's esophagus (BE) is caused by chronic reflux of the gastrointestinal tract and can progress to invasive adenocarcinoma. However, the pathophysiology, cell of origin, and management of this condition is incompletely understood. This review evaluates the role of in vivo models in resolving these debates. A search was performed on the Ovid and Pub Medline for 1964,2001 and Cochrane Collaboration. The keywords used were adenocarcinoma, animal model, Barrett's esophagus, columnar-lined esophagus, eosophageal neoplasms, and esophageal carcinogenesis. All relevant papers were scrutinized and an attempt at tabulation was made. In vivo models have been used at several stages of debate on the pathophysiology of BE. They provide conclusive evidence for its acquired nature secondary to duodenogastroesophageal reflux. The cell of origin of experimental BE may arise from adjacent columnar epithelium, basal layer multipotent cells, or esophageal glands. Experimental work on BE is lacking in assessing therapeutic modalities. [source] Distress Selling and Asset Market FeedbackFINANCIAL MARKETS, INSTITUTIONS & INSTRUMENTS, Issue 5 2007Ilhyock Shim This paper examines the process of distress selling and asset market feedback. It splits this process into several stages, in order to analyze what triggers distress selling, why asset prices fall, and how falling prices generate additional rounds of selling. This framework enables us to understand and compare models relevant to distress selling from diverse literatures. The paper also considers what policy options are available at each stage to mitigate the adverse economic consequences of distress selling and asset market feedback. [source] The mechanism of fluid infiltration in peridotites at Almklovdalen, western NorwayGEOFLUIDS (ELECTRONIC), Issue 3 2002O. Kostenko Abstract A major Alpine-type peridotite located at Almklovdalen in the Western Gneiss Region of Norway was infiltrated by aqueous fluids at several stages during late Caledonian uplift and retrogressive metamorphism. Following peak metamorphic conditions in the garnet,peridotite stability field, the peridotite experienced pervasive fluid infiltration and retrogression in the chlorite,peridotite stability field. Subsequently, the peridotite was infiltrated locally by nonreactive fluids along fracture networks forming pipe-like structures, typically on the order of 10 m wide. Fluid migration away from the fractures into the initially impermeable peridotite matrix was facilitated by pervasive dilation of grain boundaries and the formation of intragranular hydrofractures. Microstructural observations of serpentine occupying the originally fluid-filled inclusion space indicate that the pervasively infiltrating fluid was characterized by a high dihedral angle (, > 60°) and ,curled up' into discontinuous channels and fluid inclusion arrays following the infiltration event. Re-equilibration of the fluid phase topology took place by growth and dissolution processes driven by the excess surface energy represented by the ,forcefully' introduced external fluid. Pervasive fluid introduction into the peridotite reduced local effective stresses, increased the effective grain boundary diffusion rates and caused extensive recrystallization and some grain coarsening of the infiltrated volumes. Grain boundary migration associated with this recrystallization swept off abundant intragranular fluid inclusions in the original chlorite peridotite, leading to a significant colour change of the rock. This colour change defines a relatively sharp front typically located 1,20 cm away from the fractures where the nonreactive fluids originally entered the peridotite. Our observations demonstrate how crustal rocks may be pervasively infiltrated by fluids with high dihedral angles (, > 60°) and emphasize the coupling between hydrofracturing and textural equilibration of the grain boundary networks and the fluid phase topology. [source] Polyphase evolution and reaction sequence of compositional domains in metabasalt: a model based on local chemical equilibrium and metamorphic differentiationGEOLOGICAL JOURNAL, Issue 3-4 2000T. M. Toóth Abstract Eclogitic garnet amphibolite samples from the Southern Steep Belt of the Central Alps show evidence of several stages of metamorphic evolution and exhumation. A method for unravelling this evolution is presented and applied to these samples. It involves a combination of detailed petrographic analysis and microchemical characterization with quantitative models of the thermodynamically stable phase relations for specific compositional domains of each sample. Preserved mineral relics and textural evidence are compared to model predictions to identify the important irreversible reactions. The interpretation of the exhumation history is thus based on the consistency of a wide spectrum of observations with predicted phase diagrams, leading to robust reconstruction of a pressure,temperature (P,T) path even where the mineralogical relics in samples are insufficient, due to retrogression, to warrant application of multi-equilibrium thermobarometric techniques. The formation of compositionally different domains in the metabasalt samples studied is attributed to prograde growth of porphyroblasts (e.g. garnet, plagioclase, zoisite) in the matrix, implying substantial metamorphic differentiation at the scale of a few millimetres. Chemical interaction among different domains during the subsequent P,T evolution is shown to have been very limited. This led to different reaction sequences during exhumation, in which relics preserved in different domains reflect a range of continually changing P,T conditions. For samples from a single outcrop, we deduce a Barrovian prograde path to eclogite facies (23,±,3,kbar, 750,±,50°C), followed by (rapid) decompression to 8,±,1,kbar and 675,±,25°C, and a final heating phase at similar pressures reaching 750,±,40°C. This evolution is attributed to the Alpine cycle involving subduction,collision and slab breakoff,extrusion of tectonic fragments that make up the Southern Steep Belt of the Central Alps. Copyright © 2000 John Wiley & Sons, Ltd. [source] Decubitus ulcers: A review of the literatureINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 10 2005Cheryl Bansal BA Decubitus ulcers are a worldwide health care concern affecting tens of thousands of patients and costing over a billion dollars a year. Susceptibility to pressure ulcers comes from a combination of external factors (pressure, friction, shear force, and moisture), and internal factors (e.g. fever, malnutrition, anaemia, and endothelial dysfunction). Often, enough damage is done to create the basis for a decubitus ulcer after as little as 2 h of immobility, a situation which may be difficult to avoid if the patient must undergo prolonged surgery or remain bedridden. Damage owing to pressure may also occur hours before the patient receives medical attention, especially if the patient falls or becomes immobilized owing to a vascular event. Several classification systems for decubitus ulcers have been described, based on where injury first occurs. The histologic progression of decubitus ulcers is a dynamic process involving several stages, each having characteristic histologic features. A team-focused approach integrating all aspects of care, including pressure relief, infection control, nutrition, and surgery, may improve healing rates. With accurate risk assessment and preventative care, we can hope to minimize complications and mortality owing to decubitus ulcers. [source] Low-complexity unambiguous acquisition methods for BOC-modulated CDMA signalsINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 6 2008Elena Simona Lohan Abstract The new M-code signals of GPS and the signals proposed for the future Galileo systems are of split-spectrum type, where the pseudorandom (PRN) code is multiplied with rectangular sub-carriers in one or several stages. Sine and cosine binary-offset-carrier (BOC) modulations are examples of modulations, which split the signal spectrum and create ambiguities in the envelope of the autocorrelation function (ACF) of the modulated signals. Thus, the acquisition of split-spectrum signals, based on the ambiguous ACF, poses some challenges, which might be overcome at the expense of higher complexity (e.g. by decreasing the step in searching the timing hypotheses). Recently, two techniques that deal with the ambiguities of the ACF have been proposed, and they were referred to as ,sideband (SB) techniques' (by Betz, Fishman et al.) or ,BPSK-like' techniques (by Martin, Heiries et al.), since they use SB correlation channels and the obtained ACF looks similar to the ACF of a BPSK-modulated PRN code. These techniques allow the use of a higher search step compared with the ambiguous ACF situation. However, both these techniques use SB-selection filters and modified reference PRN codes at the receivers, which affect the implementational complexity. Moreover, the ,BPSK-like' techniques have been so far studied for even BOC-modulation orders (i.e. integer ratio between the sub-carrier frequency and the chip rate) and they fail to work for odd BOC-modulation orders (or equivalently for split-spectrum signals with significant zero-frequency content). We propose here three reduced-complexity methods that remove the ambiguities of the ACF of the split-spectrum signals and work for both even and odd BOC-modulation orders. Two of the proposed methods are extensions of the previously mentioned techniques, and the third one is introduced by the authors and called the unsuppressed adjacent lobes (UAL) technique. We argue via theoretical analysis the choice of the parameters of the proposed methods and we compare the alternative methods in terms of complexity and performance. Copyright © 2008 John Wiley & Sons, Ltd. [source] Applicant and Recruiter Reactions to New Technology in Selection: A Critical Review and Agenda for Future ResearchINTERNATIONAL JOURNAL OF SELECTION AND ASSESSMENT, Issue 2-3 2003Neil AndersonArticle first published online: 30 JUL 200 This paper presents a narrative review of recent research into applicant and recruiter reactions to new technology in employee selection. Different aspects of the use of new technology are noted including computer-based testing, Internet-based recruitment and candidate assessment, telephone-based and video-based interviews, video-based situational judgment tests, and virtual reality scenarios. It is argued that an appropriate way to conceptualize these advances is as ,technical innovations' as defined in the creativity and innovation research in Industrial, Work, and Organizational (IWO) psychology. Applicant reactions research is reviewed thematically, and studies into three main themes are discussed: Applicant preferences and reactions, equivalence, and adverse impact. Following Bartram (2001), an amphibian-monarchistic analogy is employed at several stages in the review. Four major criticisms of the extant applicant reactions research base are noted: its atheoretical orientation, a short-termist concentration upon reactions level outcomes, an over-reliance on students as surrogates, and a patchiness of coverage of crucial research questions. The second part of this paper explores neglected issues of recruiter adoption of new technology for employee selection. Again drawing from advances in the innovation and creativity literatures, this section explores likely antecedent factors at the individual and organizational levels of analysis. A general model of recruiter adoption of new technology is posited as a framework for future research in this area. For both applicant and recruiter reactions further research is called for and implications for practice are noted throughout. [source] Maternal and fetal microvasculature in sheep placenta at several stages of gestationJOURNAL OF ANATOMY, Issue 3 2010Shireen A. Hafez Abstract Maternal and fetal microvasculature was studied in ewes at days 50, 90 and 130 of gestation using microvascular corrosion casting and scanning electron microscopy. Microvascular corrosion casts of caruncles at day 50 were cup-shaped with a centrally located cavity. Branches of radial arteries entered the caruncle from its base and ramified on the maternal surface of the caruncle. Stem arteries broke into an extensive mesh of capillaries forming crypts on the fetal surface. The architecture of the caruncle at day 90 was similar to what was found at day 50 but the vascularity and the depth of the crypts increased in correspondence to increased branching of fetal villi. The substance of the caruncle was thicker at day 130 compared with day 50, with no remarkable difference compared with day 90. Capillary sinusoids of irregular form and diameter were observed on the fetal surface of the caruncle at all stages. These sinusoids may reduce blood flow resistance and subsequently increase transplacental exchange capacity. A microvascular corrosion cast of the cotyledon was cup-shaped with wide and narrow sides. Cotyledonary vessels entered and left the cotyledon from the narrow side. A cotyledonary artery gave proximal collateral branches immediately after entering the cotyledon and then further branched to supply the remaining portion of the cotyledon. Vessel branches broke into a mesh of capillaries forming the fetal vascular villi. Fetal villi that were nearest to the center of the cotyledon were the longest. Capillaries forming villi were in the form of a web-like mesh, were irregular in size and had sinusoidal dilations. The architecture of the cotyledon at day 90 was similar to day 50, but the vascularity increased. Branching of the fetal villi became more abundant. This extensive branching presumably allows a higher degree of invasion and surface contact to maternal tissues. At day 130, the distal portions of the fetal villi showed low ridges and troughs to increase the surface area for diffusion. Branching of fetal villi appears to influence the elaboration of maternal crypts in all stages of gestation. However, correspondence between crypts and villi is restricted to distal portions of fetal villi. [source] Determinants of skin sensitisation potentialJOURNAL OF APPLIED TOXICOLOGY, Issue 3 2008David W. Roberts Abstract Skin sensitisation is an important toxicological endpoint. The possibility that chemicals used in the workplace and in consumer products might cause skin sensitisation is a major concern for individuals, for employers and for marketing. In European REACH (Registration, Evaluation, and Authorisation of Chemicals) legislation, the sensitising potential should therefore be assessed for chemicals below the 10 ton threshold. Development of methods for prediction of skin sensitisation potential without animal testing has been an active research area for some time, but has received further impetus with the advent of REACH and the EU Cosmetics Directive (EU 2003). This paper addresses the issue of non-animal based prediction of sensitisation by a mechanistic approach. It is known that the sequence of molecular, biomolecular and cellular events between exposure to a skin sensitiser and development of the sensitised state involves several stages, in particular penetration through the stratum corneum, covalent binding to carrier protein, migration of Langerhans cells, presentation of the antigen to naïve T-cells. In this paper each of these stages is considered with respect to the extent to which it is dependent on the chemical properties of the sensitiser. The evidence suggests that, although penetration of the stratum corneum, stimulation of migration and maturation of Langerhans cells, and antigen recognition are important events in the induction of sensitisation, except in certain specific circumstances they can be taken for granted. They are not important factors in determining whether a compound will be a sensitiser or not, nor are they important factors in determining how potent one sensitiser will be relative to another. The ability to bind covalently to carrier protein is the major structure-dependent determinant of skin sensitisation potential. A chemistry-based prediction strategy is proposed involving reaction mechanistic domain assignment, reactivity and hydrophobicity determination, and application of quantitative mechanistic modelling (QMM) or read-across. Copyright © 2007 John Wiley & Sons, Ltd. [source] Temperature dependent larval resource allocation shaping adult body size in Drosophila melanogasterJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2003Z. Bochdanovits Abstract Geographical variation in Drosophila melanogaster body size is a long-standing problem of life-history evolution. Adaptation to a cold climate invariably produces large individuals, whereas evolution in tropical regions result in small individuals. The proximate mechanism was suggested to involve thermal evolution of resource processing by the developing larvae. In this study an attempt is made to merge proximate explanations, featuring temperature sensitivity of larval resource processing, and ultimate approaches focusing on adult and pre-adult life-history traits. To address the issue of temperature dependent resource allocation to adult size vs. larval survival, feeding was stopped at several stages during the larval development. Under these conditions of food deprivation, two temperate and two tropical populations reared at high and low temperatures produced different adult body sizes coinciding with different probabilities to reach the adult stage. In all cases a phenotypic trade-off between larval survival and adult size was observed. However, the underlying pattern of larval resource allocation differed between the geographical populations. In the temperate populations larval age but not weight predicted survival. Temperate larvae did not invest accumulated resources in survival, instead they preserved larval biomass to benefit adult weight. In other words, larvae from temperate populations failed to re-allocate accumulated resources to facilitate their survival. A low percentage of the larvae survived to adulthood but produced relatively large flies. Conversely, in tropical populations larval weight but not age determined the probability to reach adulthood. Tropical larvae did not invest in adult size, but facilitated their own survival. Most larvae succeeded in pupating but then produced small adults. The underlying physiological mechanism seemed to be an evolved difference in the accessibility of glycogen reserves as a result of thermal adaptation. At low rearing temperatures and in the temperate populations, glycogen levels tended to correlate positively with adult size but negatively with pupation probability. The data presented here offer an explanation of geographical variation in body size by showing that thermal evolution of resource allocation, specifically the ability to access glycogen storage, is the proximate mechanism responsible for the life-history trade-off between larval survival and adult size. [source] Use of Bean Sprout Enterobacteriaceae Isolates as Biological Control Agents of Pseudomonas fluorescensJOURNAL OF FOOD SCIENCE, Issue 1 2004K. ENOMOTOArticle first published online: 28 JUN 200 ABSTRACT: Bean sprouts were cultivated under in vitro conditions as a model system to study the mechanism of bacteria-mediated spoilage in bean sprouts. Pseudomonas fluorescens, or Erwinia spp., were inoculated onto sprouts at several stages during cultivation. Five strains of Enterobacteriaceae isolated from the native microflora of sprouts prevented Pseudomonas -mediated spoilage by co-inoculating these cultures on seeds that were soaking in water. The population of P. fluorescens in co-inoculated liquid medium culture with a strain (B1) decreased slightly. The results indicated that the Enterobacteriaceae isolates tested played an important role in preventing Pseudomonas -mediated spoilage by growing competitively with P. fluorescens. [source] Magnetic resonance microscopy at 17.6-Tesla on chicken embryos in vitroJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2001Bianca Hogers PhD Abstract The non-destructive nature and the rapid acquisition of a three-dimensional image makes magnetic resonance microscopy (MRM) very attractive and suitable for functional imaging investigations. We explored the use of an ultra high magnetic field for MRM to increase image quality per image acquisition time. Improved image quality was characterized by a better signal-to-noise ratio (SNR), better image contrast, and higher resolution compared to images obtained at lower magnetic field strengths. Fixed chicken embryos at several stages of development were imaged at 7.0-T (300 MHz) and at 17.6-T (750 MHz). Maximum intensity projection resulted in three-dimensional vascular images with ample detail of the embryonic vasculature. We showed that at 750 MHz frequency, an image with approximately three times better SNR can be obtained by T1 -weighting using a standard gadolinium contrast agent, compared to the same measurement at 300 MHz. The image contrast improved by around 20 percent and the contrast-to-noise ratio improved by almost a factor of 3.5. Smaller blood vessels of the vascular system were identified at the high field, which indicates a better image resolution. Thus, ultra high field is beneficial for MRM and opens new areas for functional imaging research, in particular when SNR, resolution, and contrast are limited by acquisition time. J. Magn. Reson. Imaging 2001;14:83,86. © 2001 Wiley-Liss, Inc. [source] Transmembrane signaling through phospholipase C-, in the developing human prefrontal cortexJOURNAL OF NEUROSCIENCE RESEARCH, Issue 1 2006Iñigo Ruiz de Azúa Abstract To investigate changes in muscarinic receptor-stimulated phospholipase C-, (PLC-,) activity during brain development, we examined the functional coupling of each of the three major protein components of the phosphoinositide system (M1, M3, and M5 muscarinic receptor subtypes; Gq/11 proteins; PLC-,1,4 isoforms) in membrane preparations from post-mortem human prefrontal cerebral cortex collected at several stages of prenatal and postnatal development. In human prenatal brain membranes, PLC was found to be present and could be activated by calcium, but the ability of guanosine-5,-o-3 thiotriphosphate (GTP,S) or carbachol (in the presence of GTP,S) to modulate prenatal PLC-, was significantly weaker than that associated with postnatal PLC-,. Western blot analysis revealed that the levels of G,q/11 did not change significantly during development. In contrast, dramatically higher levels of expression of PLC-,1,4 isoforms and of M1, M3, and M5 muscarinic receptors were detected in the child vs. the fetal brain, a finding that might underlie the observed increased activity of PLC. Thus, inositol phosphate production may be more efficiently regulated by altering the amount of effectors (PLC-,1,4) and receptors (M1,3,5 subtypes) than by altering the level of G,q/11 subunits. These results demonstrate that different PLC isoforms are expressed in the prefrontal cortex of the developing human brain in an age-specific manner, suggesting specific roles not only in synaptic transmission but also in the differentiation and maturation of neurons in the developing brain. © 2006 Wiley-Liss, Inc. [source] Follicular dendritic cells confirm lymphoid organization in the minor salivary glands of primary Sjögren's syndromeJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 9 2008Malin V. Jonsson Background:, Sjögren's syndrome (SS) is an autoimmune chronic inflammatory disorder affecting the salivary and lacrimal glands. The aim of this study was to explore immunophenotypic features of chronic inflammatory reactions in the minor salivary glands in patients with primary SS (pSS). Methods:, Formalin-fixed, paraffin-embedded labial minor salivary gland tissue sections from randomly selected patients with pSS (n = 60) were investigated for the expression of CD21, CD23, CD35 and IgD by immunohistochemistry. Results:, Based on the distribution and staining pattern of CD21, CD23, CD35 and IgD in lymphoid aggregates, several stages of chronic inflammatory reactions were observed. In 12/60 (20%) patients, lymphoid infiltrates with germinal centre (GC)-like features such as extensive networks of CD21-, CD23- and CD35-positive cells were observed in the minor salivary gland tissue. Smaller networks and,/or focal infiltrates with scattered CD21+, CD23+ and CD35+ cells were observed in the remaining 48/60 (80,%) cases. When dividing patients according to the presence (GC+) or the absence (GC,) of GC in the minor salivary glands, the mean focus score was significantly higher in the GC+ patients (P < 0.05). Double staining of the minor salivary glands revealed focal infiltrates with follicular dentritic cell networks and B cells resembling normal GCs in tonsillar tissue. Conclusion:, A particular cellular profile was demonstrated in a sub-group of patients with pSS and could be linked to serological aberrations. These findings warrant further prospective studies. [source] Dissociation of the ,001, Dislocations and Their Interactions with Dislocation Loops in Tetragonal BaTiO3JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2006Shun-Yu Cheng Dislocations in pressureless-sintered BaTiO3 ceramics have been analyzed using transmission electron microscopy. Subjected to effective sintering stresses, dislocations were generated and multiplied in plastically deformed BaTiO3 crystals by the Frank,Read mechanism from both single- and double-ended sources. This is represented by dislocations encompassing a series of square-like borders that shared a common center. All border dislocations exhibited the characteristic scallop shape. True dislocation line directions (u) were determined by trace analysis and Burgers vectors (b) by contrast analysis for the dislocations dissociated from b=,001, into two half-partials following the type (I) reaction ofby climb on {001}. Dislocation interactions between the main dislocations created from plastic deformation and dislocation loops of b=,100, or ,110, forming condensation of intrinsic Schottky vacancies were also found to obey the type (IV) reaction of, the type (V) reactions of. Migrating dislocations and loops interacting mutually in several stages, illustrated schematically, before arriving at the configuration described by types (IV) and (V) were observed and discussed. [source] Activation of large lons in FT-ICR mass spectrometryMASS SPECTROMETRY REVIEWS, Issue 2 2005Julia Laskin Abstract The advent of soft ionization techniques, notably electrospray and laser desorption ionization methods, has enabled the extension of mass spectrometric methods to large molecules and molecular complexes. This both greatly extends the applications of mass spectrometry and makes the activation and dissociation of complex ions an integral part of these applications. This review emphasizes the most promising methods for activation and dissociation of complex ions and presents this discussion in the context of general knowledge of reaction kinetics and dynamics largely established for small ions. We then introduce the characteristic differences associated with the higher number of internal degrees of freedom and high density of states associated with molecular complexity. This is reflected primarily in the kinetics of unimolecular dissociation of complex ions, particularly their slow decay and the higher energy content required to induce decomposition,the kinetic shift (KS). The longer trapping time of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) significantly reduces the KS, which presents several advantages over other methods for the investigation of dissociation of complex molecules. After discussing general principles of reaction dynamics related to collisional activation of ions, we describe conventional ways to achieve single- and multiple-collision activation in FT-ICR MS. Sustained off-resonance irradiation (SORI),the simplest and most robust means of introducing the multiple collision activation process,is discussed in greatest detail. Details of implementation of this technique, required control of experimental parameters, limitations, and examples of very successful application of SORI-CID are described. The advantages of high mass resolving power and the ability to carry out several stages of mass selection and activation intrinsic to FT-ICR MS are demonstrated in several examples. Photodissociation of ions from small molecules can be effected using IR or UV/vis lasers and generally requires tuning lasers to specific wavelengths and/or utilizing high flux, multiphoton excitation to match energy levels in the ion. Photodissociation of complex ions is much easier to accomplish from the basic physics perspective. The quasi-continuum of vibrational states at room temperature makes it very easy to pump relatively large amounts of energy into complex ions and infrared multiphoton dissociation (IRMPD) is a powerful technique for characterizing large ions, particularly biologically relevant molecules. Since both SORI-CID and IRMPD are slow activation methods they have many common characteristics. They are also distinctly different because SORI-CID is intrinsically selective (only ions that have a cyclotron frequency close to the frequency of the excitation field are excited), whereas IRMPD is not (all ions that reside on the optical path of the laser are excited). There are advantages and disadvantages to each technique and in many applications they complement each other. In contrast with these slow activation methods, the less widely appreciated activation method of surface induced dissociation (SID) appears to offer unique advantages because excitation in SID occurs on a sub-picosecond time scale, instantaneously relative to the observation time of any mass spectrometer. Internal energy deposition is quite efficient and readily adjusted by altering the kinetic energy of the impacting ion. The shattering transition,instantaneous decomposition of the ion on the surface,observed at high collision energies enables access to dissociation channels that are not accessible using SORI-CID or IRMPD. Finally, we discuss some approaches for tailoring the surface to achieve particular aims in SID. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:135,167, 2005 [source] Student perceptions about the characteristics of an effective discussion during the reporting phase in problem-based learningMEDICAL EDUCATION, Issue 9 2006Astrid J S F Visschers-Pleijers Objective, To explore student perceptions of factors contributing to the effectiveness of discussions in the reporting phase of the problem-based learning (PBL) process, where students report and synthesise the results of self-study. Methods, Forty-eight Year 1 and 2 medical students participated in 6 focus group interviews about the characteristics of effective group discussions and possible improvements. The data were analysed qualitatively in several stages. Results, The analysis yielded 4 main characteristics of effective discussions: asking for, giving and receiving explanations; integrating and applying knowledge; discussing differences with regard to learning content, and guiding and monitoring the content and the group process of the discussion. Integrating and applying knowledge included structuring, relating and summarising information and providing examples from practice. Discussing different opinions included discussing a variety of literature resources and disagreements. The main learning effects mentioned by the students were retention, understanding, integration and application of knowledge. Conclusions, Students have clear ideas about what promotes effective discussions during the reporting phase. Their PBL experience has provided them with some insights that are in line with theory and research on collaborative learning. Future research should examine differences between student and tutor perceptions of the quality of discussions. Introductions to PBL for students and tutors should include training in asking open but focused questions, supporting explanations with arguments and dealing with conflicts about learning content. Tutors should be trained in giving effective and personal feedback. Collaborative creation of external knowledge representations (i.e. concept maps) should be advocated, as should variety of literature resources. [source] Determinants of mail-survey response: Survey design factors and respondent factorsPSYCHOLOGY & MARKETING, Issue 3 2002James G. Helgeson With the use of a hierarchy-of-effects model, the decision to complete a mail survey was modeled as a process moving through several stages. A set of variables thought to influence the survey-completion decision process was examined. These variables include survey design factors, which were manipulated by the researchers, and respondent factors, such as attitudinal and personal constructs. Based on the research findings, the hierarchy-of-effects model is an appropriate way to model the mail-survey-response process. The data indicate that among the survey design factors included in the study, the monetary incentive had the most effect on the decision process, with a pervasive impact throughout the process. Importantly, respondent factors such as attitude toward research were of critical importance in moving respondents through the survey-response process. Research into the response-rate phenomenon is likely to benefit by considering how both survey design and respondent factors affect specific stages of the response process and enhance participation in surveys. © 2002 Wiley Periodicals, Inc. [source] In vitro Follicle Growth: Achievements in Mammalian SpeciesREPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2001R Cortvrindt The exact mechanisms regulating in vivo folliculogenesis in mammalians have only been partly unravelled. Some processes, such as the initiation of growth of primordial follicles are still poorly understood. This increases the difficulty to culture follicles in vitro as the primordial follicles will be the ultimate starting material for culture. There are important species differences in regulation and timing of maturation, which makes it difficult to transpose techniques. Only in the mouse model, live pups were born when primordial or early preantral follicles were cultured entirely in vitro. Although no systems are as yet permitting complete in vitro culture of early follicle stages in large animals or humans, parts of folliculogenesis have been successfully reproduced in vitro. This review summarizes achievements of the last years in follicle culturing starting off at several stages of development. Future applications of in vitro follicle culture include fertility preservation for humans, preservation of rare animal species and creation of oocyte banks for research. [source] Comparative spermatogenesis, spermatocytogenesis, and spermatozeugmata formation in males of viviparous species of clinid fishes (Teleostei: Clinidae, Blennioidei)THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 3 2007Lev Fishelson Abstract Spermatogenesis and spermatocytogenesis in 16 species of viviparous clinid fishes (Clinidae, Blennioidei) from various localities were followed for the first time by means of light and electron microscopy. The testes of the studied species are of the lobular type, with germinal stem cells situated at the apical ends of the lobules and a vas efferens along the internal margin. Maturation of the spermatides takes place in spermatocysts formed by Sertoli cells around the B-spermatogonia. The gradual condensation and relocation of the chromosomes along the nuclei membranes are highly prominent in this process, which can be divided into several stages. Anisodiametric and slightly flattened sperm heads are eventually formed, 0.4,0.5 ,m in diameter and 7.5 ± 1 ,m long, bearing 80 ± 15 ,m long flagella. The sperms are packed into spermatozeugmata within the spermatocysts, enveloped and penetrated by the mucotic material of the Sertoli cells. With division of the germ cells and maturation of the spermatids, the spermatocyst dimensions increase, attaining 40 ± 8 ,m in diameter in the smaller species of Heteroclinus, and up to 90 ± 10 ,m in the larger males of Clinus superciliosus and C. cottoides. Accordingly, the volume of the maturing spermatocysts attains ca. 1,300 ± 100 ,m3 in the smaller species, and ca. 6,500 ± 300 ,m3 in the larger ones. As sperm head volume is ca. 2.24 ,m3, the number of sperm in the smallest mature spermatocysts reaches ca. 440 and in the largest over 2,900. Upon release from the cysts, the spermatozeugmata are transported along the sperm ducts to the posterior ampullae where they are stored in the epididymis. During copulation, the sperms are transported from there to the female via the intromittent organ. The sperm formation parameters and their structure and numbers are discussed. Anat Rec Part A, 2007. © 2007 Wiley-Liss, Inc. [source] Three-dimensional anatomy of the conduction system of the early embryonic rabbit heartTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 1 2006Florence Rothenberg Abstract The complete embryonic cardiac conduction system is difficult to view in three dimensions, primarily because there has not been a marker of all segments of the normal system throughout all stages of development. Imaging of the conduction system components within the atria has been particularly controversial because different markers reveal different pathways that may or may not represent conduction system components. The conduction system of the adult and embryonic rabbit, however, can be labeled in its entirety with the neurofilament marker, NF-160. The conduction system of rabbit embryos at several stages of development spanning cardiac septation was therefore investigated. Optical mapping of the electrical signature of the conduction system previously revealed a close correlation between the cardiac activation patterns and the anatomy as shown by serial sections. The 3D relationship between the components of the conduction system could only be inferred from the 2D sections. The sections were consequently reconstructed using a commercial software program (AutoQuant). This is the first demonstration of the three-dimensional complete normal rabbit embryonic cardiac conduction system at several stages of development. © 2005 Wiley-Liss, Inc. [source] Specialization, Context of Production, and Alienation in the Production Process: Comments and AfterthoughtsARCHEOLOGICAL PAPERS OF THE AMERICAN ANTHROPOLOGICAL ASSOCIATION, Issue 1 2007Yung-ti Li The study of craft specialization has gone through several stages since the pioneering work of Childe, each with changing foci and emphases. The current volume marks yet another development in the field that demonstrates both discontents with existing theories and efforts to enhance and strengthen the discourse. Acting as a commentator to facilitate further discussion, the first half of my chapter addresses specific issues in individual chapters, while the second half explores another dimension of production by looking at bronze and pottery production in ancient and premodern China. Whereas some contributors examine alienability in the social role of the objects and the rights over alienation of the product, this discussion examines another form of alienation that can be considered in the study of craft production, one that is both salient and tangible in archaeological data: alienation of the manufacturing process, that is, alienation of the craft producers from their own skills. The work of Ursula Franklin on Shang bronze production is reviewed, and new studies on porcelain production at Jingdezhen and stoneware production at Yixing are incorporated to further develop Franklin's model. I argue that through examining the material patterns of the production process and the type range of finished products, alienation in the workplace can be detected archaeologically. [source] Application of Genomics in Preclinical Drug Safety EvaluationBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 6 2006Peter G. Lord Toxicologists have traditionally gathered pathological, morphological, chemical and biochemical information from in vivo studies of preclinical species in order to assess drug safety and to determine how new drugs can be safely administered to the human patient population. In recent years the emerging "-omics" technologies have been developed and integrated into preclinical studies in order to better assess drug safety by gaining information on the cellular and molecular events underlying adverse drug reactions. Genomics approaches in particular have become readily available and are being applied in several stages of drug development. The burgeoning literature on what has become known as "toxicogenomics" has for the most part highlighted successful applications of gene expression profiling in predictive toxicology, enabling decisions to be made on the developability of a compound early in the drug development process. It is also becoming apparent that toxicogenomic approaches are good starting points to develop experiments designed to gain a mechanistic insight into drug toxicities within and across species. Gene expression arrays permit the measurement of responses of essentially all the genes in the entire genome to be monitored, and knowledge of the function of the genes affected can identify the potential mechanisms to then be confirmed using conventional biochemical, toxicological and pathological approaches. As toxicologists put these technologies into practice they build up a knowledge base to better characterize toxicities at the molecular level and to make the search for much needed, novel biomarkers of toxicity more achievable. [source] Unravelling the multi-stage burial history of the Swiss Molasse Basin: integration of apatite fission track, vitrinite reflectance and biomarker isomerisation analysisBASIN RESEARCH, Issue 1 2006Martin Mazurek ABSTRACT A complex basin evolution was studied using various methods, including thermal constraints based on apatite fission-track (AFT) analysis, vitrinite reflectance (VR) and biomarker isomerisation, in addition to a detailed analysis of the regional stratigraphic record and of the lithological properties. The study indicates that (1) given the substantial amount of data, the distinction and characterisation of successive stages of heating and burial in the same area are feasible, and (2) the three thermal indicators (AFT, VR and biomarkers) yield internally consistent thermal histories, which supports the validity of the underlying kinetic algorithms and their applicability to natural basins. All data pertaining to burial and thermal evolution were integrated in a basin model, which provides constraints on the thickness of eroded sections and on heat flow over geologic time. Three stages of basin evolution occurred in northern Switzerland. The Permo-Carboniferous strike,slip basin was characterised by high geothermal gradients (80,100°C km,1) and maximum temperature up to 160°C. After the erosion of a few hundreds of metres in the Permian, the post-orogenic, epicontinental Mesozoic basin developed in Central Europe, with subsidence triggered by several stages of rifting. Geothermal gradients in northern Switzerland during Cretaceous burial were relatively high (35,40°C km,1), and maximum temperature typically reached 75°C (top middle Jurassic) to 100°C (base Mesozoic). At least in the early Cretaceous, a stage of increased heat flow is needed to explain the observed maturity level. After erosion of 600,700 m of Cretaceous and late Jurassic strata during the Paleocene, the wedge-shaped Molasse Foreland Basin developed. Geothermal gradients were low at this time (,20°C km,1). Maximum temperature of Miocene burial exceeded that of Cretaceous burial in proximal parts (<35 km from the Alpine front), but was lower in more distal parts (>45 km). Thus, maximum temperature as well as maximum burial depth ever reached in Mesozoic strata occurred at different times in different regions. Since the Miocene, 750,1050 m were eroded, a process that still continues in the proximal parts of the basin. Current average geothermal gradients in the uppermost 2500 m are elevated (32,47°C km,1). They are due to a Quaternary increase of heat flow, most probably triggered by limited advective heat transport along Paleozoic faults in the crystalline basement. [source] Automated classification of Plasmodium sporozoite movement patterns reveals a shift towards productive motility during salivary gland infectionBIOTECHNOLOGY JOURNAL, Issue 6 2009Stephan Hegge Abstract The invasive stages of malaria and other apicomplexan parasites use a unique motility machinery based on actin, myosin and a number of parasite-specific proteins to invade host cells and tissues. The crucial importance of this motility machinery at several stages of the life cycle of these parasites makes the individual components potential drug targets. The different stages of the malaria parasite exhibit strikingly diverse movement patterns, likely reflecting the varied needs to achieve successful invasion. Here, we describe a Tool for Automated Sporozoite Tracking (ToAST) that allows the rapid simultaneous analysis of several hundred motile Plasmodium sporozoites, the stage of the malaria parasite transmitted by the mosquito. ToAST reliably categorizes different modes of sporozoite movement and can be used for both tracking changes in movement patterns and comparing overall movement parameters, such as average speed or the persistence of sporozoites undergoing a certain type of movement. This allows the comparison of potentially small differences between distinct parasite populations and will enable screening of drug libraries to find inhibitors of sporozoite motility. Using ToAST, we find that isolated sporozoites change their movement patterns towards productive motility during the first week after infection of mosquito salivary glands. [source] | ||||||||||||||||||||||||||||