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Selected AbstractsAnalysis of Meox - 2 mutant mice reveals a novel postfusion-based cleft palateDEVELOPMENTAL DYNAMICS, Issue 2 2006Jiu-Zhen Jin Abstract Cleft palate represents a common human congential disease involving defects in the development of the secondary palate. Major steps in mammalian palatogenesis include vertical growth, elevation, and fusion of the palate shelves. Our current study with the homeobox gene Meox - 2 during mouse secondary palate development reveals a novel postfusion-based mechanism for cleft palate. Meox - 1 and Meox - 2 are two functionally related homeobox genes playing important roles in somitogenesis and limb muscle differentiation. We found that the expression of Meox - 2, not Meox - 1, marks the specification of early mouse palatal mesenchymal cells in the maxillary processes at embryonic day 11.5 (E11.5). From E12.5 to E15.5, the expression of Meox - 2 occupies only the posterior part of the palate, providing an early molecular marker for the anterior,posterior polarity in mouse secondary palate formation. A total of 35.3% of Meox - 2,/, (n = 17) and 25.5% of Meox - 2+/, (n = 55) mouse embryos display a cleft palate phenotype at E15.5, indicating that the reduction of Meox - 2 function is associated with susceptibility to cleft palate. Unlike previously reported clefts, none of the clefts found in Meox - 2 mutants contain any epithelial sheets in the medial edge areas, and detailed examination revealed that the clefts resulted from the breakdown of newly fused palates. This article is the first report of a gene required to maintain adherence of the palatal shelves after fusion. Developmental Dynamics 235:539,546, 2006. © 2005 Wiley-Liss, Inc. [source] Kinematics, Dynamics, Biomechanics: Evolution of Autonomy in Game AnimationCOMPUTER GRAPHICS FORUM, Issue 3 2005Steve Collins The believeable portrayal of character performances is critical in engaging the immersed player in interactive entertainment. The story, the emotion and the relationship between the player and the world they are interacting within are hugely dependent on how appropriately the world's characters look, move and behave. We're concerned here with the character's motion; with next generation game consoles like Xbox360TM and Playstation®3 the graphical representation of characters will take a major step forward which places even more emphasis on the motion of the character. The behavior of the character is driven by story and design which are adapted to game context by the game's AI system. The motion of the characters populating the game's world, however, is evolving to an interesting blend of kinematics, dynamics, biomechanics and AI drivenmotion planning. Our goal here is to present the technologies involved in creating what are essentially character automata, emotionless and largely brainless character shells that nevertheless exhibit enough "behavior" to move as directed while adapting to the environment through sensing and actuating responses. This abstracts the complexities of low level motion control, dynamics, collision detection etc. and allows the game's artificial intelligence system to direct these characters at a higher level. While much research has already been conducted in this area and some great results have been published, we will present the particular issues that face game developers working on current and next generation consoles, and how these technologies may be integrated into game production pipelines so to facilitate the creation of character performances in games. The challenges posed by the limited memory and CPU bandwidth (though this is changing somewhat with next generation) and the challenges of integrating these solutions with current game design approaches leads to some interesting problems, some of which the industry has solutions for and some others which still remain largely unsolved. [source] The mushroom bodies , prominent brain centres of arthropods and annelids with enigmatic evolutionary originACTA ZOOLOGICA, Issue 1 2010Rudi Loesel Abstract Loesel, R. and Heuer, C.M. 2010. The mushroom bodies , prominent brain centres of arthropods and annelids with enigmatic evolutionary origin. ,Acta Zoologica (Stockholm) 91: 29,34 Mushroom bodies (MBs) are the most prominent and conspicuous neuropils in the brain of arthropods, onychophorans and vagile polychaete annelids but have not been described in any other animal group with complex brain architecture. Due to a number of unique neuroanatomical characters MBs can easily be identified and distinguished from other brain centres. However, their evolutionary origin and the question whether MBs are homologous structures is still under debate. This paper will briefly summarize the available morphological data and their implications with respect to the molecular evidence on early metazoan radiation. Unraveling the origin of MBs is an example of the challenges neurophylogenists will face in the future, especially so since it will signify a major step towards reconstructing early metazoan brain evolution. [source] Reference Minerals for the Microanalysis of Light ElementsGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 2-3 2001M. Darby Dyar tourmaline; danburite; spodumène; muscovite; isotopes The quantitative determination of light element concentrations in geological specimens represents a major analytical challenge as the electron probe is generally not suited to this task. With the development of new in situ analytical techniques, and in particular the increasing use of secondary ion mass spectrometry, the routine determination of Li, Be and B contents has become a realistic goal. However, a major obstacle to the development of this research field is the critical dependence of SIMS on the availability of well characterized, homogeneous reference materials that are closely matched in matrix (composition and structure) to the sample being studied. Here we report the first results from a suite of large, gem crystals which cover a broad spectrum of minerals in which light elements are major constituents. We have characterized these materials using both in situ and wet chemical techniques. The samples described here are intended for distribution to geochemical laboratories active in the study of light elements. Further work is needed before reference values for these materials can be finalized, but the availability of this suite of materials represents a major step toward the routine analysis of the light element contents of geological specimens. La détermination quantitative des concentrations en éléments légers dans les échantillons géologiques représente un défi analytique majeur, la sonde électronique ne convenant généralement pas pour ce travail. Avec le développement de nouvelles techniques analytiques in situ, en particulier l'utilisation grandissante de la spectrométrie ionique secondaire, la détermination en routine des teneurs en Li, Be et B est devenue un objectif réaliste. Toutefois, un obstacle majeur dans le développement de cette recherche subsiste : la technique SIMS est dépendante de la disponibilité de matériaux de référence bien caractérisés et homogènes proches en composition et en structure de l'échantillon étudié. Nous rapportons ici les premiers résultats obtenus à partie d'un groupe de grands cristaux de qualité gemme recouvrant un large spectre de minéraux composés essentiellement d'éléments légers. Nous avons caractérisé ces matériaux en utilisant à la fois des techniques in situ et par voie humide. Les échantillons décrits ici vont être distribués dans les laboratoires de géochimie spécialisés dans l'étude des éléments légers. Avant la conclusion des valeurs de référence de ces matériaux, des travaux ultérieurs seront nécessaires, mais la disponibilité de l'ensemble de ces matériaux représente une étape importante vers l'analyse en routine des teneurs en éléments légers d'échantillons géologiques. [source] The Rule of Law in the Realm and the Province of New York: Prelude to the American RevolutionHISTORY, Issue 301 2006HERBERT A. JOHNSON British and American views of public law have diverged greatly over the past two hundred years. This article examines the evolution of New York's adherence to the rule of fundamental law and the use of colonial common law courts to protect the rights of New York subjects against the prerogative power of the crown. As a conquered province from 1664 to 1683, New York was denied a legislature. Thereafter the colonial legislative bodies were active in making unsuccessful attempts to claim their birthright as Englishmen. In England the Glorious Revolution represented a major step in the development of parliamentary supremacy. In New York, however, it facilitated an ethnic insurrection followed by the realization that English governmental policy mandated the denial of basic rights of Englishmen to colonial residents. The Glorious Revolution simply made it possible for parliament, as well as the crown, to regulate colonial affairs without any constitutional restrictions prior to 1774. In terms of constitutional dynamics in eighteenth-century England, continued imperial rule through an untrammelled royal prerogative substantially increased the political power and revenues of the crown. Failing to consider the impact of monarchial power in a growing empire, the 1688,9 Convention Parliament laid the foundation for an unbalanced British government in the middle of the eighteenth century. Deprived of patronage and extraordinary revenues at home, the monarchs turned to regulation of their empire and to reaping increased financial benefit. Both of these unintended consequences of the Glorious Revolution threatened parliamentary supremacy, even as parliament's new-found power began to undermine the rule of law in the empire. [source] Threshold changes in vegetation along a grazing gradient in Mongolian rangelandsJOURNAL OF ECOLOGY, Issue 1 2008Takehiro Sasaki Summary 1The concept of threshold has become important in ecology, but the nature of potential threshold responses of vegetation to grazing in rangeland ecosystems remains poorly understood. We aimed to identify ecological thresholds in vegetation changes along a grazing gradient and to examine whether threshold changes were expressed similarly at a variety of ecological sites. 2To accomplish this, we surveyed the vegetation along grazing gradients at 10 ecological sites, each located at different landscape positions in Mongolia's central and southern rangelands. Evidence for a threshold in changes in floristic composition along the grazing gradient was examined by comparing linear models of the data with nonlinear models fitted using an exponential curve, an inverse curve, a piecewise regression and a sigmoid logistic curve. 3Three nonlinear models (piecewise, exponential and sigmoid) provided a much better fit to the data than the linear models, highlighting the presence of a discontinuity in vegetation changes along the grazing gradient. The shapes of the best-fit models and their fit to the data were generally similar across sites, indicating that the changes in floristic composition were relatively constant below a threshold level of grazing, after which the curve changed sharply. 4Except for two sites, the best-fit models had relatively narrow bootstrap confidence intervals (95% CI), especially around threshold points or zones where the rate of change accelerated, emphasizing that our results were robust and conclusive. 5Synthesis. Our study provided strong evidence for the existence of ecological thresholds in vegetation change along a grazing gradient across all ecological sites. This suggests that vegetation responses to grazing in the study areas are essentially nonlinear. The recognition that real threshold changes exist in real grazing gradients will help land managers to prevent the occurrence of undesirable states and promote the occurrence of desirable states, and will therefore permit a major step forward in the sustainable management of rangeland ecosystems. [source] Hospitalists and intensivists: Partners in caring for the critically ill,The time has come,JOURNAL OF HOSPITAL MEDICINE, Issue 1 2010Michael Heisler MD Abstract A report by the Committee on Manpower for Pulmonary and Critical Care Societies (COMPACCS), published in 2000, predicted that beginning in 2007 a gap between the demand and availability of intensivists in the United States would become apparent and steadily increase to 22% by 2020 and to 35% by 2030. Subsequent reports have reiterated those projections including a report to congress in 2006 by the U.S. Department of Health and Human Services/Health Resources and Services Administration. This "gap" has been called a health system "crisis" by multiple authors. Two important documents have published specific recommendations for how to resolve this crisis: the Framing Options for Critical Care in the United States (FOCCUS) Task Force Report in 2004 and the Prioritizing the Organization and Management of Intensive Care Services in the Unites States (PrOMIS) Conference Report in 2007. Since the initial COMPACCS report and since these 2 additional reports were published, a new opportunity to take a major step in resolving this crisis has emerged: the growing number of hospitalists providing critical care services at secondary and tertiary care facilities. According to the 2005/2006 Society of Hospital Medicine (SHM) National Survey, that number has increased to 75%. Since the number of intensivists is unlikely to change significantly over the next 25 years, the question is no longer "if" hospitalists should be in the intensive care unit (ICU); rather the question is how to assure quality and improved clinical outcomes through enhanced collaboration between hospital medicine and critical care medicine. Journal of Hospital Medicine 2010;5:1,3. © 2010 Society of Hospital Medicine. [source] Designing poly(amido amine) dendrimers containing core diversities by click chemistry of the propargyl focal point poly(amido amine) dendronsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2008Jae Wook Lee Abstract General, fast, efficient, and inexpensive methods for the synthesis of poly (amido amine) (PAMAM) dendrimers having core diversities were elaborated. In all syntheses, the major step involved an inexpensive 1,3-dipolar cycloaddition reaction between an alkyne and an azide in the presence of Cu(I) species, which is known as the best example of click chemistry. The propargyl-functionalized PAMAM dendrons are obtained by the divergent approach using propargylamine as an alkyne-focal point. Three core building blocks, 1,3,5-tris(azidomethyl)benzene, N,N,N,,N, -tetra(azidopropylamidoethyl)-1,2-diaminoethane, and 4,4,-(3,5-bis(azidopropyloxy)benzyloxy)bisphenyl, were designed and synthesized to serve as the azide functionalities for dendrimer growth via click reactions with the alkyne-dendrons. These three building blocks were employed together with the propargyl-functionalized PAMAM dendrons in a convergent strategy to synthesize three kinds of PAMAM dendrimers with different core units. This novel and pivotal strategy using an efficient click methodology provides the fast and efficient synthesis of the PAMAM dendrimers with the tailed made core units. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1083,1097, 2008 [source] IPCC and palaeoclimate , an evolving story?,JOURNAL OF QUATERNARY SCIENCE, Issue 1 2010Chris J. Caseldine Abstract The introductory comments to the Special Issue: IPCC and palaeoclimate, concentrate on considering how the role of palaeoclimate research has evolved over the two decades of IPCC Reports. There have been significant changes in the nature and prominence of palaeoclimate research examined with the Fourth Assessment Report (FAR) representing a major step in giving such research a high profile. The implications of this for future palaeoclimate research are briefly reviewed. Copyright © 2010 John Wiley & Sons, Ltd. [source] Genetics and Neuroscience in Dyslexia: Perspectives for Education and RemediationMIND, BRAIN, AND EDUCATION, Issue 4 2007Gerd Schulte-Körne ABSTRACT , Our understanding of the causes of a developmental disorder like dyslexia has received recent input from both neuroscience and genetics. The discovery of 4 candidate genes for dyslexia and the identification of neuronal networks engaged when children read and spell are the basis for introducing this knowledge into education. However, the input from educational practitioners as well as empirical knowledge from research on learning also contribute significantly to our understanding of how children acquire the basic skills for learning to read and spell. It is imperative to merge the knowledge acquired from research in the fields of neuroscience, genetics, and empirical education, as well as to understand how the learning brain and instruction interact. Doing so can be seen as a major step in attaining an optimal approach for teaching, reading, and spelling and for finding the best suited and most effective treatment concepts for dyslexic children and adolescents. [source] The generation of nisin variants with enhanced activity against specific Gram-positive pathogensMOLECULAR MICROBIOLOGY, Issue 1 2008Des Field Summary Nisin is the prototype of the lantibiotic group of antimicrobial peptides. It exhibits broad spectrum inhibition of Gram-positive bacteria including important food pathogens and clinically relevant antibiotic-resistant bacteria. Significantly, the gene-encoded nature of nisin means that it can be subjected to gene-based bioengineering to generate novel derivatives. Here, we take advantage of this to generate the largest bank of randomly mutated nisin derivatives reported to date, with the ultimate aim of identifying variants with enhanced bioactivity. This approach led to the identification of a nisin-producing strain with enhanced bioactivity against the mastitic pathogen Streptococcus agalactiae resulting from an amino acid change in the hinge region of the peptide (K22T). Prompted by this discovery, site-directed and site-saturation mutagenesis of the hinge region residues was employed, resulting in the identification of additional derivatives, most notably N20P, M21V and K22S, with enhanced bioactivity and specific activity against Gram-positive pathogens including Listeria monocytogenes and/or Staphylococcus aureus. The identification of these derivatives represents a major step forward in the bioengineering of nisin, and lantibiotics in general, and confirms that peptide engineering can deliver derivatives with enhanced antimicrobial activity against specific problematic spoilage and pathogenic microbes or against Gram-positive bacteria in general. [source] Order 637 a major step forwardNATURAL GAS & ELECTRICITY (PREVIOUSLY : NATURAL GAS), Issue 10 2000Richard G. Smead [source] Missing link identified: GpBAR1 is a neuronal bile acid receptorNEUROGASTROENTEROLOGY & MOTILITY, Issue 7 2010S. J. Keely Abstract,In addition to their classical functions in aiding the digestion and absorption of lipids, bile acids are increasingly gaining appreciation for their roles in regulating intestinal physiology. Bile acids are now widely considered as hormones that exert a wide range of physiological and pathophysiological effects both within and outside the gastrointestinal (GI) tract. The discovery of the bile acid receptor, GpBAR1, represented a major step forward in our understanding of how cells can sense and respond to bile acids. GpBAR1 is a cell surface G protein-coupled receptor expressed on adipose tissue and skeletal muscle where it has been found to be an important regulator of cellular metabolism. In a paper published in the current issue of Neurogastroenterology and Motility, Poole et al. investigated the expression and function of GpBAR1 in mouse intestine. They found the receptor to be expressed throughout the GI tract but predominantly on nerves within the myenteric and submucosal plexuses. Employing in vitro and in vivo techniques they demonstrated that activation of GpBAR1 by bile acids inhibits small and large intestinal motor function and delays intestinal transit. The effects of GpBAR1 activation are mediated through activation of cholinergic and nitrergic interneurons. The data reported by Poole et al. provides novel and exciting insights into how bile acids exert their actions in the intestine. This Editorial Viewpoint aims to further consider the potential physiological and pathophysiological implications of their findings. [source] Review: Familial Parkinson's disease , genetics, clinical phenotype and neuropathology in relation to the common sporadic form of the diseaseNEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 3 2008Carola Schiesling The identification of the first gene in familial Parkinson's disease (PD) only 10 years ago was a major step in the understanding of the molecular mechanisms in neurodegeneration. Alpha-synuclein aggregation was not only recognized as a key event in neurodegeneration in patients carrying mutations in this gene, but it turned out to be the most consistent marker to define Lewy body pathology also in non-heritable idiopathic PD (IPD). Subsequent comprehensive pathoanatomical studies of IPD brains led to a novel concept of an ascending pathological process in variable stages that are reflected by alpha-synuclein aggregation at specific predilection sites. To date, more than seven genes are known to cause familial PD. The fact that these genetic forms of Parkinsonism present with clinical features indistinguishable from IPD, but may display neuropathological features that are not consistent with IPD, underscores the need of a more differentiated approach to familial and sporadic forms of Parkinsonism. Indeed, in distinct populations, mutations in one single gene were found to cause the disease in up to 40% of patients formerly described as ,idiopathic' cases. These findings indicate that IPD, as defined by a late-onset disorder with no (apparent) genetic contribution, is part of a clinical syndrome that becomes more and more heterogeneous in terms of aetiology, with overlapping clinical and pathoanatomical features. Thus in the present review, we discuss clues from familial PD to our understanding of the molecular pathogenesis of neurodegeneration with special consideration of the variable clinical and neuropathological aspects. [source] Unintentionally doped InN grown onto an atomically flat AlN intermediate layer using plasma-assisted molecular beam epitaxyPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 7 2006K. R. Wang Abstract Unintentionally doped InN has been grown onto an atomically flat AlN intermediate layer on top of the Si(111) substrate using plasma-assisted molecular beam epitaxy (PA-MBE). Though there are lots of micrometer-size indium droplets randomly distributed on the top of the surface, the highest electron mobility of this InN thin film measured at room temperature by van der Pauw method is still higher than 1000 cm2/V s with a carrier concentration of 5,8.9 × 1018 cm,3. A symmetrical X-ray rocking curve is measured and the full-width-at-half-maximum (FWHM) of this sample is 1089 arcsec. In the meantime, the threading dislocation (TD) density of this material is estimated to around 9.8 × 108 cm,2 , 7.5 × 109 cm,2 depending on the probing regions that are studied by the etching technique and field-emission scanning electron microscopy (FE-SEM). (2 × 1) in situ reflection high-energy electron diffraction (RHEED) patterns show that this sample is grown under In-rich environment with possible In-terminated surface. From the FE-SEM pictures which were taken from the samples after 10 minutes etching in hydrochloride, the surface morphology shows In-polarity-like patterns that coincide with those procured in RHEED. To select and grow a high-quality laminated AlN as intermediate layer is believed to be the major step in obtaining this high electron mobility InN thin film on Si substrate. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Size matters: the value of small populations for wintering waterbirdsANIMAL CONSERVATION, Issue 3 2004Sarah F. Jackson Protecting systematically selected areas of land is a major step towards biodiversity conservation worldwide. Indeed, the identification and designation of protected areas more often than not forms a core component of both national and international conservation policies. In this paper we provide an overview of those Special Protection Areas and Ramsar Sites that have been classified in Great Britain as of 1998/99 for a selection of wintering waterbird species, using bird count data from the Wetland Bird Survey. The performance of this network of sites is remarkable, particularly in comparison with published analyses of networks elsewhere in the world. Nevertheless, the current site-based approach, whilst having the great benefit of simplicity, is deliberately biased towards aggregating species at the expense of the more dispersed distribution species. To ensure that the network continues successfully to protect nationally and internationally important waterbird populations, efforts now need to concentrate on the derivation of species-specific representation targets and, in particular, the ways in which these can be incorporated into the site selection process. Although these analyses concern the performance of protected areas for waterbirds in Great Britain, the results have wide-ranging importance for conservation planning in general and the design of protected area networks. [source] The eastward displacement of a freely falling body on the rotating Earth: Newton and Hooke's debate of 1679ANNALEN DER PHYSIK, Issue 8 2010W. Dittrich Abstract In this article I would like to tell the story of the beginning of modern theoretical physics, freed from all kinds of questionable anecdotes which have entered the scientific literature over the centuries. It all began in the seventeenth century when the mathematical theory of astronomy began to take shape. A major step in the history of modern science was taken when a few members of The Royal Society in London realized that the laws ruling the motions of heavenly bodies as manifested in Kepler's three laws are also effective in the dynamics of Earth-bound particle motion. Everything started, not with I. Newton, but with R. Hooke. Not Newton's falling apple (Voltaire's invention), but a far-reaching response by R. Hooke to a letter by I. Newton, dated November 28, 1679, ignited Newton's interest in gravity. That letter contained the famous spiral which a falling body would follow when released from a certain height above the surface of the Earth. Hooke's answer, based on Keplerian orbits, expressed the opinion that the body's trajectory would rather follow an elliptical path. In his spiral sketch Newton, however, predicted correctly that the falling body would be found to suffer an eastward deviation from the vertical in consequence of the Earth's rotation. In the course of time, many a researcher, including Hooke himself, was able to verify this conjecture. But it took until 1803 for the first satisfactory calculation of the eastward displacement of a freely falling body to be performed, and was provided by C.F. Gauss. [source] Proof of a decomposition theorem for symmetric tensors on spaces with constant curvatureANNALEN DER PHYSIK, Issue 8 2008N. Straumann Abstract In cosmological perturbation theory a first major step consists in the decomposition of the various perturbation amplitudes into scalar, vector and tensor perturbations, which mutually decouple. In performing this decomposition one uses , beside the Hodge decomposition for one-forms , an analogous decomposition of symmetric tensor fields of second rank on Riemannian manifolds with constant curvature. While the uniqueness of such a decomposition follows from Gauss' theorem, a rigorous existence proof is not obvious. In this note we establish this for smooth tensor fields, by making use of some important results for linear elliptic differential equations. [source] Spermatogonial stem cells: characteristics and experimental possibilities,APMIS, Issue 11-12 2005PEDRO M. APONTE The continuation of the spermatogenic process throughout life relies on a proper regulation of self-renewal and differentiation of the spermatogonial stem cells. These are single cells situated on the basal membrane of the seminiferous epithelium. Only 0.03% of all germ cells are spermatogonial stem cells. They are the only cell type that can repopulate and restore fertility to congenitally infertile recipient mice following transplantation. Although numerous expression markers have been helpful in isolating and enriching spermatogonial stem cells, such as expression of THY-1 and GFR,-1 and absence of c-kit, no specific marker for this cell type has yet been identified. Much effort has been put into developing a protocol for the maintenance of spermatogonial cells in vitro. Recently, coculture systems of testicular cells on various feeder cells have made it possible to culture spermatogonial stem cells for a long period of time, as was demonstrated by the transplantation assay. Even expansion of testicular cells, including the spermatogonial stem cells, has been achieved. In these culture systems, hormones and growth factors are investigated for their role in the process of proliferation of spermatogonial stem cells. At the moment the best culture system known still consists of a mixture of testicular cells with about 1.33% spermatogonial stem cells. Recently pure SV40 large T immortalized spermatogonial stem cell lines have been established. These c-kit-negative cell lines did not show any differentiation in vitro or in vivo. A telomerase immortalized c-kit-positive spermatogonial cell line has been established that was able to differentiate in vitro. Spermatocytes and even spermatids were formed. However, spermatogonial stem cell activity by means of the transplantation assay was not tested for this cell line. Both the primary long-term cultures and immortalized cell lines have represented a major step forward in investigating the regulation of spermatogonial self-renewal and differentiation, and will be useful for identifying specific molecular markers. [source] Persea americana (avocado): bringing ancient flowers to fruit in the genomics eraBIOESSAYS, Issue 4 2008André S. Chanderbali The avocado (Persea americana) is a major crop commodity worldwide. Moreover, avocado, a paleopolyploid, is an evolutionary "outpost" among flowering plants, representing a basal lineage (the magnoliid clade) near the origin of the flowering plants themselves. Following centuries of selective breeding, avocado germplasm has been characterized at the level of microsatellite and RFLP markers. Nonetheless, little is known beyond these general diversity estimates, and much work remains to be done to develop avocado as a major subtropical-zone crop. Among the goals of avocado improvement are to develop varieties with fruit that will "store" better on the tree, show uniform ripening and have better post-harvest storage. Avocado transcriptome sequencing, genome mapping and partial genomic sequencing will represent a major step toward the goal of sequencing the entire avocado genome, which is expected to aid in improving avocado varieties and production, as well as understanding the evolution of flowers from non-flowering seed plants (gymnosperms). Additionally, continued evolutionary and other comparative studies of flower and fruit development in different avocado strains can be accomplished at the gene expression level, including in comparison with avocado relatives, and these should provide important insights into the genetic regulation of fruit development in basal angiosperms. BioEssays 30:386,396, 2008. © 2008 Wiley Periodicals, Inc. [source] Sterile Versus Nonsterile Gloves During Mohs Micrographic Surgery: Infection Rate is not AffectedDERMATOLOGIC SURGERY, Issue 2 2006BRANDON M. RHINEHART MC BACKGROUND: Mohs micrographic surgery (MMS) is an outpatient procedure, which has become the treatment of choice for certain cutaneous malignancies. Although the major steps in this procedure are relatively standardized, one difference involves the use of sterile or nonsterile, clean gloves during the tumor removal phase. OBJECTIVE: This retrospective, chart review study was performed to evaluate whether infection rates are affected by the use of sterile versus nonsterile gloves in the tumor extirpation phase of MMS. METHODS: This study evaluated the surgical records of 1,810 consecutive Mohs patients, of which 1,239 Mohs patients (1,400 Mohs procedures) met inclusion criteria. Age, sex, tumor diagnosis, anatomic location, number of Mohs stages, area of defect, closure type, cartilage exposure, and sterile versus nonsterile glove use were recorded and evaluated. RESULTS: Twenty-five infections were identified. Statistically significant infection rates were discovered for patients with cartilage fenestration with secondary healing and malignant melanoma diagnosis only. There was no statistical difference in infection rates with all other measured variables to include the use of sterile or clean, nonsterile gloves. CONCLUSION: Our study lends support that clean, nonsterile gloves are safe and effective for use in the tumor extirpation phase of MMS, at a significant cost savings. [source] Growth and differentiation of the developing limb bud from the perspective of chondrogenesisDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 6 2007Hirohito Shimizu Limb skeletal elements develop from a cartilage template, which is formed by the process termed chondrogenesis. This process is crucial in determining the shape and size of definitive bones in vertebrates. During chondrogenesis, aggregated mesenchymal cells undergo a highly organized process of proliferation and maturation along with secretion of extracellular matrix followed by programmed cell death and replacement by bone. The molecular mechanisms underlying this sophisticated process have been extensively studied. It has been demonstrated that several transcription factors such as Sox genes and Runx genes are indispensable for the major steps in chondrogenesis. Additionally, a number of signaling molecules including Bmps, Fgfs and Ihh/PTHrP are known to regulate chondrogenesis through highly coordinated interactions. This review is meant to provide an overview of the current knowledge of chondrogenesis with particular emphasis on the cellular and molecular aspects. [source] Competence of New Emergency Medicine Residents in the Performance of Lumbar PuncturesACADEMIC EMERGENCY MEDICINE, Issue 7 2005Richard L. Lammers MD Abstract Background: Medical students are taught some procedural skills during medical school, but there is no uniform set of procedures that all students learn before residency. Objective: To determine the level of competence in the performance of a lumbar puncture (LP) by new postgraduate year 1 (PGY1) emergency medicine (EM) residents. Methods: An observational study was conducted at three EM residencies with 42 PGY1 residents who recently graduated from 26 various medical schools. The LP procedure was divided into 26 major and 44 minor steps to create a scoring protocol. The model, procedure, and scoring protocol were validated by experienced emergency physicians. Subjects performed the procedure without interruption or feedback on an LP training model using a standard LP kit. A step was scored as "performed correctly" if two of the three evaluators concurred. Pre- and poststudy questionnaires assessed subjects' prior instruction and clinical experience with LP, self-confidence, sense of relevance, motivation, and fatigue. Results: Subjects completed an average of 14.8 (57%; 95% confidence interval [95% CI] = 53% to 61%) of the major steps (range: 4,26) and 19.1 (43%; 95% CI = 42% to 45%) of the minor steps (range: 7,28) in 14.3 minutes (range: 3,22). Sixty-nine percent failed to obtain cerebrospinal fluid from the model. Subjects' levels of confidence changed slightly on a five-point scale from 2.8 ("little-to-some") before the test to 2.5 after the test. Eighty-three percent of the subjects previously performed LPs on patients during medical school (average attempts = 2.2; range: 0,10), but only 40% of those who did so were supervised by an attending during their first attempt. Conclusions: In the cohort studied, new PGY1 EM residents had not attained competence in performing LPs from training in medical school. Most new PGY1 residents probably require training, practice, and close, direct supervision of this procedure by attending physicians until the residents demonstrate competent performance. [source] Six major steps in animal evolution: are we derived sponge larvae?EVOLUTION AND DEVELOPMENT, Issue 2 2008Claus Nielsen SUMMARY A review of the old and new literature on animal morphology/embryology and molecular studies has led me to the following scenario for the early evolution of the metazoans. The metazoan ancestor, "choanoblastaea," was a pelagic sphere consisting of choanocytes. The evolution of multicellularity enabled division of labor between cells, and an "advanced choanoblastaea" consisted of choanocytes and nonfeeding cells. Polarity became established, and an adult, sessile stage developed. Choanocytes of the upper side became arranged in a groove with the cilia pumping water along the groove. Cells overarched the groove so that a choanocyte chamber was formed, establishing the body plan of an adult sponge; the pelagic larval stage was retained but became lecithotrophic. The sponges radiated into monophyletic Silicea, Calcarea, and Homoscleromorpha. Homoscleromorph larvae show cell layers resembling true, sealed epithelia. A homoscleromorph-like larva developed an archenteron, and the sealed epithelium made extracellular digestion possible in this isolated space. This larva became sexually mature, and the adult sponge-stage was abandoned in an extreme progenesis. This eumetazoan ancestor, "gastraea," corresponds to Haeckel's gastraea. Trichoplax represents this stage, but with the blastopore spread out so that the endoderm has become the underside of the creeping animal. Another lineage developed a nervous system; this "neurogastraea" is the ancestor of the Neuralia. Cnidarians have retained this organization, whereas the Triploblastica (Ctenophora+Bilateria), have developed the mesoderm. The bilaterians developed bilaterality in a primitive form in the Acoelomorpha and in an advanced form with tubular gut and long Hox cluster in the Eubilateria (Protostomia+Deuterostomia). It is indicated that the major evolutionary steps are the result of suites of existing genes becoming co-opted into new networks that specify new structures. The evolution of the eumetazoan ancestor from a progenetic homoscleromorph larva implies that we, as well as all the other eumetazoans, are derived sponge larvae. [source] Discovering hidden knowledge in data classification via multivariate analysisEXPERT SYSTEMS, Issue 2 2010Yisong Chen Abstract: A new classification algorithm based on multivariate analysis is proposed to discover and simulate the grading policy on school transcript data sets. The framework comprises three major steps. First, factor analysis is adopted to separate the scores of several different subjects into grading-related ones and grading-unrelated ones. Second, multidimensional scaling is employed for dimensionality reduction to facilitate subsequent data visualization and interpretation. Finally, a support vector machine is trained to classify the filtered data into different grades. This work provides an attractive framework for intelligent data analysis and decision making. It also exhibits the advantages of high classification accuracy and supports intuitive data interpretation. [source] Corporate Governance in IndiaJOURNAL OF APPLIED CORPORATE FINANCE, Issue 1 2008Rajesh Chakrabarti The Indian corporate governance system has both supported and held back India's ascent to the top ranks of the world's economies. While on paper the country's legal system provides some of the best investor protection in the world, enforcement is a major problem, with overburdened courts and significant corruption. Ownership remains concentrated and family business groups continue to be the dominant business model, with significant pyramiding and evidence of tunneling activity that transfers cash flow and value from minority to controlling shareholders. But for all its shortcomings, Indian corporate governance has taken major steps toward becoming a system capable of inspiring confidence among institutional and, increasingly, foreign investors. The Securities and Exchanges Board of India (SEBI), which was established as part of the comprehensive economic reforms launched in 1991, has made considerable progress in becoming a rigorous regulatory regime that helps ensure transparency and fair practice. And the National Stock Exchange of India, also established as part of the reforms, now functions with enough efficiency and transparency to be generating the third-largest number of trades in the world, just behind the NASDAQ and NYSE. Among more recent changes, the enactment of Sarbanes,Oxley type measures in 2004,which includes protections for minority shareholders in family- or "promoter"-led businesses,has contributed to recent increases in institutional and foreign stock ownership. And while family- and government-controlled business groups continue to be the rule, India has also seen the rise of successful companies like Infosys that are free of the influence of a dominant family or group and have made the individual shareholder their central governance focus. [source] Intestinal Calcium Transporter Genes Are Upregulated by Estrogens and the Reproductive Cycle Through Vitamin D Receptor-Independent Mechanisms,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2003SJ Van Cromphaut Abstract 1,,25(OH)2 -vitamin D strongly regulates the expression of the epithelial calcium channel CaT1. CaT1 expression is reduced in ERKO, mice and induced by estrogen treatment, pregnancy, or lactation in VDR WT and KO mice. Estrogens and vitamin D are thus independent potent regulators of the expression of this calcium influx mechanism, which is involved in active intestinal calcium absorption. Introduction: Active duodenal calcium absorption consists of three major steps: calcium influx into, transfer through, and extrusion out of the enterocyte. These steps are carried out by the calcium transport protein 1 (CaT1), calbindin-D9K, and the plasma membrane calcium ATPase (PMCA1b), respectively. We investigated whether estrogens or hormonal changes during the female reproductive cycle influence the expression of these genes, and if so, whether these effects are vitamin D-vitamin D receptor (VDR) dependent. Materials and Methods: We evaluated duodenal expression patterns in estrogen receptor (ER), and -, knockout (KO) mice, as well as in ovariectomized, estrogen-treated, pregnant, and lactating VDR wild-type (WT) and VDR KO mice. Results: Expression of calcium transporter genes was not altered in ERKO, mice. CaT1 mRNA expression was reduced by 55% in ERKO, mice, while the two other calcium transporter genes were not affected. Ovariectomy caused no change in duodenal expression pattern of VDR WT and KO mice, whereas treatment with a pharmacologic dose of estrogens induced CaT1 mRNA expression in VDR WT (4-fold) and KO (8-fold) mice. Pregnancy enhanced CaT1 expression equally in VDR WT and KO mice (12-fold). Calbindin-D9K and PMCA1b expression increased to a lesser extent and solely in pregnant VDR WT animals. In lactating VDR WT and KO mice, CaT1 mRNA expression increased 13 times, which was associated with a smaller increase in calbindin-D9K protein content and PMCA1b mRNA expression. Conclusions: Estrogens or hormonal changes during pregnancy or lactation have distinct, vitamin D-independent effects at the genomic level on active duodenal calcium absorption mechanisms, mainly through a major upregulation of the calcium influx channel CaT1. The estrogen effects seem to be mediated solely by ER,. [source] Ion flux through membrane channels,An enhanced algorithm for the Poisson-Nernst-Planck modelJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 12 2008Witold Dyrka Abstract A novel algorithmic scheme for numerical solution of the 3D Poisson-Nernst-Planck model is proposed. The algorithmic improvements are universal and independent of the detailed physical model. They include three major steps: an adjustable gradient-based step value, an adjustable relaxation coefficient, and an optimized segmentation of the modeled space. The enhanced algorithm significantly accelerates the speed of computation and reduces the computational demands. The theoretical model was tested on a regular artificial channel and validated on a real protein channel,,-hemolysin, proving its efficiency. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2008 [source] OPTIMIZATION OF NATTOKINASE PRODUCTION CONDUCTION USING RESPONSE SURFACE METHODOLOGYJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2006DJA-SHIN WANG ABSTRACT Natto has attracted worldwide attention because of its health benefits and long history in Japanese food. It has been found that a potent fibrinolytic enzyme named nattokinase, which is extracted from natto, is able to prevent atherosclerosis. The production of nattokinase may be influenced by various factors such as temperature, shaking speed, volume of medium, fermentation time and so forth. Three-step response surface methodology was applied to obtain the optimal operation conditions of the fermentation process in order to maximize the nattokinase yield. The three major steps are described as follows. First, the important factors for fermentation were identified by L8 orthogonal array experiment. The chosen factors were temperature (37 or 45C), shaking speed (110 or 150 rpm), volume of medium (80 or 120 mL), Brix of wheat bran extract (1.5 or 3°), Brix of soy meal extract (1 or 2°), glucose concentration (0.6 or 1.2%) and fermentation time (24 or 36 h). Second, a regression equation was established between the response (i.e., the enzyme activity) and the two statistically significant factors (i.e., the volume of medium and fermentation time). Third, the optimal solutions for the volume of medium and fermentation time were obtained based on the response surface of the regression equation. According to the response surface analysis, the optimal operation conditions for the fermentation process should be 80 mL and 37.0817 h for the volume of medium and the fermentation time, respectively, which resulted in 459.11 FU/mL as the predicted enzyme activity. [source] Separation of chiral mixtures in real SMB units: The FlexSMB-LSRE®AICHE JOURNAL, Issue 1 2010Pedro Sá Gomes Abstract In this work, a procedure for the separation of a racemic mixture of guaifenesin onto a chiral stationary phase (Chiralpak AD), by means of Simulated Moving Bed (SMB) technology, is presented in four major steps: (1) search for the suitable stationary and mobile phases; (2) determination of sorption parameters and validation by frontal analysis; (3) modeling and design of the SMB unit; and (4) operation and demonstration. A major emphasis is given to the common deviations that "real" SMB units present when compared with the theoretical apparatus (due to tubing and equipment dead volumes, switching time asymmetries and delays, pumps flow rates variations). These deviations are analyzed before and after the design and construction of the FlexSMB-LSRE® unit, a new flexible unit, hereby presented. A detailed model that takes into account tubing and equipment dead volumes, as well as switching time asymmetries and delay, was used to study and compare different dead volumes design and compensating strategies. It is shown that all these approaches can be converged into a switching time compensating strategy. This approach served to predict the experimental operating conditions and run a classical SMB experiment, which afterwards was compared with the simulated profiles obtained for the FlexSMB-LSRE® unit. The result of the separation was guaifenesin enantiomers with purities above 98% and a productivity value of 23 genantiomer/(dm3 CSP day). © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] | |||||||||||||||||||||||||||||||