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Sample records for pubmed growth patterns

  1. A Study on Pubmed Search Tag Usage Pattern: Association Rule Mining of a Full-day Pubmed Query Log

    PubMed Central

    2013-01-01

    Background The practice of evidence-based medicine requires efficient biomedical literature search such as PubMed/MEDLINE. Retrieval performance relies highly on the efficient use of search field tags. The purpose of this study was to analyze PubMed log data in order to understand the usage pattern of search tags by the end user in PubMed/MEDLINE search. Methods A PubMed query log file was obtained from the National Library of Medicine containing anonymous user identification, timestamp, and query text. Inconsistent records were removed from the dataset and the search tags were extracted from the query texts. A total of 2,917,159 queries were selected for this study issued by a total of 613,061 users. The analysis of frequent co-occurrences and usage patterns of the search tags was conducted using an association mining algorithm. Results The percentage of search tag usage was low (11.38% of the total queries) and only 2.95% of queries contained two or more tags. Three out of four users used no search tag and about two-third of them issued less than four queries. Among the queries containing at least one tagged search term, the average number of search tags was almost half of the number of total search terms. Navigational search tags are more frequently used than informational search tags. While no strong association was observed between informational and navigational tags, six (out of 19) informational tags and six (out of 29) navigational tags showed strong associations in PubMed searches. Conclusions The low percentage of search tag usage implies that PubMed/MEDLINE users do not utilize the features of PubMed/MEDLINE widely or they are not aware of such features or solely depend on the high recall focused query translation by the PubMed’s Automatic Term Mapping. The users need further education and interactive search application for effective use of the search tags in order to fulfill their biomedical information needs from PubMed/MEDLINE. PMID:23302604

  2. A study on PubMed search tag usage pattern: association rule mining of a full-day PubMed query log.

    PubMed

    Mosa, Abu Saleh Mohammad; Yoo, Illhoi

    2013-01-09

    The practice of evidence-based medicine requires efficient biomedical literature search such as PubMed/MEDLINE. Retrieval performance relies highly on the efficient use of search field tags. The purpose of this study was to analyze PubMed log data in order to understand the usage pattern of search tags by the end user in PubMed/MEDLINE search. A PubMed query log file was obtained from the National Library of Medicine containing anonymous user identification, timestamp, and query text. Inconsistent records were removed from the dataset and the search tags were extracted from the query texts. A total of 2,917,159 queries were selected for this study issued by a total of 613,061 users. The analysis of frequent co-occurrences and usage patterns of the search tags was conducted using an association mining algorithm. The percentage of search tag usage was low (11.38% of the total queries) and only 2.95% of queries contained two or more tags. Three out of four users used no search tag and about two-third of them issued less than four queries. Among the queries containing at least one tagged search term, the average number of search tags was almost half of the number of total search terms. Navigational search tags are more frequently used than informational search tags. While no strong association was observed between informational and navigational tags, six (out of 19) informational tags and six (out of 29) navigational tags showed strong associations in PubMed searches. The low percentage of search tag usage implies that PubMed/MEDLINE users do not utilize the features of PubMed/MEDLINE widely or they are not aware of such features or solely depend on the high recall focused query translation by the PubMed's Automatic Term Mapping. The users need further education and interactive search application for effective use of the search tags in order to fulfill their biomedical information needs from PubMed/MEDLINE.

  3. Pattern, Growth and Control

    PubMed Central

    Lander, Arthur D.

    2011-01-01

    The view of biology as goal-directed engineering has deep historical roots in developmental biology, a field currently benefitting from an influx of ideas and methods from systems biology. Systems biology draws on non-biological paradigms to explain developmental mechanisms of control, the specific type of regulation that achieves or maintains a desired end. This review highlights some of the current efforts designed to elucidate basic design principles underlying the engineering objectives of robustness, precision, and scaling that are required during developmental control of growth and pattern formation. Examples from vertebrate and invertebrate development are used to illustrate general principles including the value of integral feedback in achieving set-point control; the usefulness of self-organizing behavior; the importance of recognizing and appropriately handling noise; and the No Free Lunch theory. Through the examination of such principles, systems biology offers a functional framework to make sense of the mechanistic complexity of organismal development. PMID:21414486

  4. Remarkable Growth of Open Access in the Biomedical Field: Analysis of PubMed Articles from 2006 to 2010

    PubMed Central

    Kurata, Keiko; Morioka, Tomoko; Yokoi, Keiko; Matsubayashi, Mamiko

    2013-01-01

    Introduction This study clarifies the trends observed in open access (OA) in the biomedical field between 2006 and 2010, and explores the possible explanations for the differences in OA rates revealed in recent surveys. Methods The study consists of a main survey and two supplementary surveys. In the main survey, a manual Google search was performed to investigate whether full-text versions of articles from PubMed were freely available. Target samples were articles published in 2005, 2007, and 2009; the searches were performed a year after publication in 2006, 2008, and 2010, respectively. Using the search results, we classified the OA provision methods into seven categories. The supplementary surveys calculated the OA rate using two search functions on PubMed: “LinkOut” and “Limits.” Results The main survey concluded that the OA rate increased significantly between 2006 and 2010: the OA rate in 2010 (50.2%) was twice that in 2006 (26.3%). Furthermore, majority of OA articles were available from OA journal (OAJ) websites, indicating that OAJs have consistently been a significant contributor to OA throughout the period. OA availability through the PubMed Central (PMC) repository also increased significantly. OA rates obtained from two supplementary surveys were lower than those found in the main survey. “LinkOut” could find only 40% of OA articles in the main survey. Discussion OA articles in the biomedical field have more than a 50% share. OA has been achieved through OAJs. The reason why the OA rates in our surveys are different from those in recent surveys seems to be the difference in sampling methods and verification procedures. PMID:23658683

  5. Remarkable growth of open access in the biomedical field: analysis of PubMed articles from 2006 to 2010.

    PubMed

    Kurata, Keiko; Morioka, Tomoko; Yokoi, Keiko; Matsubayashi, Mamiko

    2013-01-01

    This study clarifies the trends observed in open access (OA) in the biomedical field between 2006 and 2010, and explores the possible explanations for the differences in OA rates revealed in recent surveys. The study consists of a main survey and two supplementary surveys. In the main survey, a manual Google search was performed to investigate whether full-text versions of articles from PubMed were freely available. Target samples were articles published in 2005, 2007, and 2009; the searches were performed a year after publication in 2006, 2008, and 2010, respectively. Using the search results, we classified the OA provision methods into seven categories. The supplementary surveys calculated the OA rate using two search functions on PubMed: "LinkOut" and "Limits." The main survey concluded that the OA rate increased significantly between 2006 and 2010: the OA rate in 2010 (50.2%) was twice that in 2006 (26.3%). Furthermore, majority of OA articles were available from OA journal (OAJ) websites, indicating that OAJs have consistently been a significant contributor to OA throughout the period. OA availability through the PubMed Central (PMC) repository also increased significantly. OA rates obtained from two supplementary surveys were lower than those found in the main survey. "LinkOut" could find only 40% of OA articles in the main survey. OA articles in the biomedical field have more than a 50% share. OA has been achieved through OAJs. The reason why the OA rates in our surveys are different from those in recent surveys seems to be the difference in sampling methods and verification procedures.

  6. Pattern formation with proportionate growth

    NASA Astrophysics Data System (ADS)

    Dhar, Deepak

    It is a common observation that as baby animals grow, different body parts grow approximately at same rate. This property, called proportionate growth is remarkable in that it is not encountered easily outside biology. The models of growth that have been studied in Physics so far, e.g diffusion -limited aggregation, surface deposition, growth of crystals from melt etc. involve only growth at the surface, with the inner structure remaining frozen. Interestingly, patterns formed in growing sandpiles provide a very wide variety of patterns that show proportionate growth. One finds patterns with different features, with sharply defined boundaries. In particular, even with very simple rules, one can produce patterns that show striking resemblance to those seen in nature. We can characterize the asymptotic pattern exactly in some special cases. I will discuss in particular the patterns grown on noisy backgrounds. Supported by J. C. Bose fellowship from DST (India).

  7. Pattern and determinants of HIV research productivity in sub-Saharan Africa: bibliometric analysis of 1981 to 2009 PubMed papers

    PubMed Central

    2010-01-01

    Background Several bibliometric studies have been published on AIDS. The findings obtained from these studies have provided a general picture of the history and growth of AIDS literature. However, factors related to variation in HIV research productivity in sub-Saharan Africa have not been examined. Therefore, this study aims to fill some of the gap in existing research to provide insights into factors associated with HIV research productivity in sub-Saharan Africa. Methods A bibliometric analysis regarding sub-Saharan Africa HIV/AIDS research was conducted in the PubMed database for the period of 1981 to 2009. The numbers of HIV research articles indexed in PubMed was used as surrogate for total HIV research productivity. Series of univariable and multivariable negative binomial regression models were used to explore factors associated with variation in HIV research productivity in sub-Saharan Africa. Results First authors from South Africa, Uganda and Kenya contributed almost half of the total number of HIV articles indexed in PubMed between 1981 and 2009. Uganda, Zimbabwe and Malawi had better records when the total production was adjusted for gross domestic product (GDP). Comoros, the Gambia and Guinea-Bissau were the most productive countries when the total products were normalized by number of people with HIV. There were strong positive and statistically significant correlation between countries number of indexed journal (Pearson correlation r = 0.77, p = .001), number of higher institutions (r = 0.60, p = .001), number of physicians (r = 0.83, p = .001) and absolute numbers of HIV articles. Conclusions HIV research productivity in Africa is highly skewed. To increase HIV research output, total expenditure on health (% of GDP), private expenditure on health, and adult literacy rate may be important factors to address. PMID:20205717

  8. Modelling urban growth patterns

    NASA Astrophysics Data System (ADS)

    Makse, Hernán A.; Havlin, Shlomo; Stanley, H. Eugene

    1995-10-01

    CITIES grow in a way that might be expected to resemble the growth of two-dimensional aggregates of particles, and this has led to recent attempts1á¤-3 to model urban growth using ideas from the statistical physics of clusters. In particular, the model of diffusion-limited aggregation4,5 (DLA) has been invoked to rationalize the apparently fractal nature of urban morphologies1. The DLA model predicts that there should exist only one large fractal cluster, which is almost perfectly screened from incoming á¤~development unitsᤙ (representing, for example, people, capital or resources), so that almost all of the cluster growth takes place at the tips of the clusterᤙs branches. Here we show that an alternative model, in which development units are correlated rather than being added to the cluster at random, is better able to reproduce the observed morphology of cities and the area distribution of sub-clusters (á¤~towns') in an urban system, and can also describe urban growth dynamics. Our physical model, which corresponds to the correlated percolation model6á¤-8 in the presence of a density gradient9, is motivated by the fact that in urban areas development attracts further development. The model offers the possibility of predicting the global properties (such as scaling behaviour) of urban morphologies.

  9. Nonlinear growth of periodic patterns.

    PubMed

    Villain-Guillot, Simon; Josserand, Christophe

    2002-09-01

    We study the growth of a periodic pattern in one dimension for a model of spinodal decomposition, the Cahn-Hilliard equation. We particularly focus on the intermediate region, where the nonlinearity cannot be neglected anymore, and before the coalescence dominates. The dynamics is captured through the standard technique of a solubility condition performed over a particular family of quasistatic solutions. The main result is that the dynamics along this particular class of solutions can be expressed in terms of a simple ordinary differential equation. The density profile of the stationary regime found at the end of the nonlinear growth is also well characterized. Numerical simulations correspond satisfactorily to the analytical results through three different methods and asymptotic dynamics are well recovered, even far from the region where the approximations hold.

  10. The concept of pattern in craniofacial growth.

    PubMed

    Moyers, R E; Bookstein, F L; Guire, K E

    1979-08-01

    1. There are semantic and associated problems with the word pattern in biology, particularly in orthodontics and facial growth. 2. Pattern, as we use the term, is invariance of relationships--"a set of constraints operating to preserve the integration of parts under varying conditions and through time." 3. Craniofacial pattern can be described and quantified by the identification of craniofacial constants, measures that are relatively invariant. 4. Growth is change and is best identified by studying those measures of size and shape that vary most sensitively through time over development stages. 5. The many traditional cephalometric measures that represent well neither pattern nor growth (mixed) are of less clinical utility than either pure pattern indices or growth indices. 6. The analytical and conceptual separation of pattern and growth seems useful in analysis of morphology, analysis of growth, prediction of growth, and clinical treatment planning.

  11. Association between overbite and craniofacial growth pattern.

    PubMed

    Claro, Cristiane Aparecida de Assis; Abrão, Jorge; Reis, Silvia Augusta Braga

    2010-01-01

    The purpose of the present study was to assess the association between overbite and craniofacial growth pattern. The sample comprised eighty-six cephalograms obtained during the orthodontic pretreatment phase and analyzed using the Radiocef program to identify the craniofacial landmarks and perform orthodontic measurements. The variables utilized were overbite, the Jarabak percentage and the Vert index, as well as classifications resulting from the interpretation of these measurements. In all the statistical tests, a significance level of 5% was considered. Measurement reliability was checked by calculating method error. Weighted Kappa analysis showed that agreement between the facial types defined by the Vert index and the direction of growth trend established by the Jarabak percentage was not satisfactory. Owing to this lack of equivalency, a potential association between overbite and craniofacial growth pattern was evaluated using the chi-square test, considering the two methods separately. No relationship of dependence between overbite and craniofacial growth pattern was revealed by the results obtained. Therefore, it can be concluded that the classification of facial growth pattern will not be the same when considering the Jarabak and the Ricketts anayses, and that increased overbite cannot be associated with a braquifacial growth pattern, nor can openbite be associated with a dolichofacial growth pattern.

  12. Exponential Growth through Pattern Exploration

    ERIC Educational Resources Information Center

    Brown, Betty

    2005-01-01

    Participants at the Summer Institute Pattern Exploration: Integration Math and Science in the Middle Grades used and developed a method treat arithmetic, algebra and geometry as one entity. The use of iterative geometric constructions is seen to reinforce the concepts of exponents, ratios and algebraic expressions for the nth stage of the…

  13. Orienteering: Growth Patterns in the United States.

    ERIC Educational Resources Information Center

    Jeffery, Charles F.

    The history of orienteering in the United States includes both military and civilian interest, with the period of greatest growth between 1970 and 1980. To investigate growth patterns in orienteering, questionnaires were mailed to 42 civilian orienteering clubs and 286 universities supporting senior Reserve Office Training Corps (ROTC)…

  14. Orienteering: Growth Patterns in the United States.

    ERIC Educational Resources Information Center

    Jeffery, Charles F.

    The history of orienteering in the United States includes both military and civilian interest, with the period of greatest growth between 1970 and 1980. To investigate growth patterns in orienteering, questionnaires were mailed to 42 civilian orienteering clubs and 286 universities supporting senior Reserve Office Training Corps (ROTC)…

  15. Predicting clicks of PubMed articles.

    PubMed

    Mao, Yuqing; Lu, Zhiyong

    2013-01-01

    Predicting the popularity or access usage of an article has the potential to improve the quality of PubMed searches. We can model the click trend of each article as its access changes over time by mining the PubMed query logs, which contain the previous access history for all articles. In this article, we examine the access patterns produced by PubMed users in two years (July 2009 to July 2011). We explore the time series of accesses for each article in the query logs, model the trends with regression approaches, and subsequently use the models for prediction. We show that the click trends of PubMed articles are best fitted with a log-normal regression model. This model allows the number of accesses an article receives and the time since it first becomes available in PubMed to be related via quadratic and logistic functions, with the model parameters to be estimated via maximum likelihood. Our experiments predicting the number of accesses for an article based on its past usage demonstrate that the mean absolute error and mean absolute percentage error of our model are 4.0% and 8.1% lower than the power-law regression model, respectively. The log-normal distribution is also shown to perform significantly better than a previous prediction method based on a human memory theory in cognitive science. This work warrants further investigation on the utility of such a log-normal regression approach towards improving information access in PubMed.

  16. Predicting clicks of PubMed articles

    PubMed Central

    Mao, Yuqing; Lu, Zhiyong

    2013-01-01

    Predicting the popularity or access usage of an article has the potential to improve the quality of PubMed searches. We can model the click trend of each article as its access changes over time by mining the PubMed query logs, which contain the previous access history for all articles. In this article, we examine the access patterns produced by PubMed users in two years (July 2009 to July 2011). We explore the time series of accesses for each article in the query logs, model the trends with regression approaches, and subsequently use the models for prediction. We show that the click trends of PubMed articles are best fitted with a log-normal regression model. This model allows the number of accesses an article receives and the time since it first becomes available in PubMed to be related via quadratic and logistic functions, with the model parameters to be estimated via maximum likelihood. Our experiments predicting the number of accesses for an article based on its past usage demonstrate that the mean absolute error and mean absolute percentage error of our model are 4.0% and 8.1% lower than the power-law regression model, respectively. The log-normal distribution is also shown to perform significantly better than a previous prediction method based on a human memory theory in cognitive science. This work warrants further investigation on the utility of such a log-normal regression approach towards improving information access in PubMed. PMID:24551386

  17. Horn growth patterns in Alpine chamois.

    PubMed

    Corlatti, Luca; Gugiatti, Alessandro; Imperio, Simona

    2015-06-01

    The analysis of horn growth may provide important information about the allocation of metabolic resources to secondary sexual traits. Depending on the selective advantages offered by horn size during intra- and inter-specific interactions, ungulates may show different investment in horn development, and growth variations within species may be influenced by several parameters, such as sex, age, or resource availability. We investigated the horn growth patterns in two hunted populations of Alpine chamois (Rupicapra r. rupicapra) in the Central Italian Alps. We tested the role of individual heterogeneity on the growth pattern and explored the variation in annulus length as a function of different factors (sex, age, hunting location, cohort). We then investigated the mechanisms underlying horn growth trajectories to test for the occurrence of compensatory or recovery growth and their potential differences between sexes and populations. Annulus length varied as a function of sex, age of individuals and, marginally, hunting location; no effect of cohort or individual heterogeneity was detected. Male and female chamois showed compensatory horn growth within the first 5½ years of life, though the partial convergence of horn trajectories in chamois suggests that this mechanisms would best be described as 'recovery growth'. Compensation rates were greater in males than in females, while only compensatory growth rates up to 2½ years of age were different in the two populations. Besides confirming the sex- and age-dependent pattern of horn development, our study suggests that the mechanism of recovery growth supports the hypothesis of horn size as a weakly selected sexual trait in male and female chamois. Furthermore, the greater compensation rates in horn growth shown by male chamois possibly suggest selective effects of hunting on age at first reproduction, while different compensation rates between populations may suggest the occurrence of some plasticity in resource

  18. Stochasticity in plant cellular growth and patterning.

    PubMed

    Meyer, Heather M; Roeder, Adrienne H K

    2014-01-01

    Plants, along with other multicellular organisms, have evolved specialized regulatory mechanisms to achieve proper tissue growth and morphogenesis. During development, growing tissues generate specialized cell types and complex patterns necessary for establishing the function of the organ. Tissue growth is a tightly regulated process that yields highly reproducible outcomes. Nevertheless, the underlying cellular and molecular behaviors are often stochastic. Thus, how does stochasticity, together with strict genetic regulation, give rise to reproducible tissue development? This review draws examples from plants as well as other systems to explore stochasticity in plant cell division, growth, and patterning. We conclude that stochasticity is often needed to create small differences between identical cells, which are amplified and stabilized by genetic and mechanical feedback loops to begin cell differentiation. These first few differentiating cells initiate traditional patterning mechanisms to ensure regular development.

  19. Stochasticity in plant cellular growth and patterning

    PubMed Central

    Meyer, Heather M.; Roeder, Adrienne H. K.

    2014-01-01

    Plants, along with other multicellular organisms, have evolved specialized regulatory mechanisms to achieve proper tissue growth and morphogenesis. During development, growing tissues generate specialized cell types and complex patterns necessary for establishing the function of the organ. Tissue growth is a tightly regulated process that yields highly reproducible outcomes. Nevertheless, the underlying cellular and molecular behaviors are often stochastic. Thus, how does stochasticity, together with strict genetic regulation, give rise to reproducible tissue development? This review draws examples from plants as well as other systems to explore stochasticity in plant cell division, growth, and patterning. We conclude that stochasticity is often needed to create small differences between identical cells, which are amplified and stabilized by genetic and mechanical feedback loops to begin cell differentiation. These first few differentiating cells initiate traditional patterning mechanisms to ensure regular development. PMID:25250034

  20. Deciphering Dynamical Patterns of Growth Processes

    ERIC Educational Resources Information Center

    Kolakowska, A.

    2009-01-01

    Large systems of statistical physics often display properties that are independent of particulars that characterize their microscopic components. Universal dynamical patterns are manifested by the presence of scaling laws, which provides a common insight into governing physics of processes as vastly diverse as, e.g., growth of geological…

  1. Deciphering Dynamical Patterns of Growth Processes

    ERIC Educational Resources Information Center

    Kolakowska, A.

    2009-01-01

    Large systems of statistical physics often display properties that are independent of particulars that characterize their microscopic components. Universal dynamical patterns are manifested by the presence of scaling laws, which provides a common insight into governing physics of processes as vastly diverse as, e.g., growth of geological…

  2. Growth patterns of Hawaiian Stilt chicks

    USGS Publications Warehouse

    Reed, J.M.; Gray, E.M.; Lewis, D.; Oring, L.W.; Coleman, R.; Burr, T.; Luscomb, P.

    1999-01-01

    We studied chick growth and plumage patterns in the endangered Hawaiian Stilt (Himantopus mexicanus knudseni). Body mass of captive chicks closely fit a Gompertz growth curve, revealing a growth coefficient (K) of 0.065 day-1 and point of inflection (T) of 17 days. When chicks fledged about 28 days after hatching, they weighed only 60% of adult body mass; at 42 d, birds still were only 75% of adult mass; culmen, tarsus, and wing chord at fledging also were less than adult size. This trend of continued growth to adult size after fledging is typical for most shorebirds. After hatching, captive chicks grew more rapidly than wild chicks, probably because of an unlimited food supply. We found no evidence for adverse effects of weather on the growth of wild chicks. As with other shorebirds, the tarsus started relatively long, with culmen and then wing chord growing more rapidly in later development. Tarsal and wing chord growth were sigmoidal, whereas culmen growth was linear. We describe plumage characteristics of weekly age classes of chicks to help researchers age birds in the wild.

  3. Growth and patterning in the conodont skeleton

    PubMed Central

    Donoghue, P. C. J.

    1998-01-01

    Recent advances in our understanding of conodont palaeobiology and functional morphology have rendered established hypotheses of element growth untenable. In order to address this problem, hard tissue histology is reviewed paying particular attention to the relationships during growth of the component hard tissues comprising conodont elements, and ignoring a priori assumptions of the homologies of these tissues. Conodont element growth is considered further in terms of the pattern of formation, of which four distinct types are described, all possibly derived from a primitive condition after heterochronic changes in the timing of various developmental stages. It is hoped that this may provide further means of unravelling conodont phylogeny. The manner in which the tissues grew is considered homologous with other vertebrate hard tissues, and the elements appear to have grown in a way similar to the growing scales and growing dentition of other vertebrates.

  4. Atypical Growth Pattern of an Intraparenchymal Meningioma

    PubMed Central

    Chen, Xiaoxi

    2016-01-01

    Meningiomas are the most common primary nonneuroglial extra-axial neoplasms, which commonly present as spherical or oval masses with a dural attachment. Meningiomas without dural attachment are rare and, according to their locations, are classified into 5 varieties, including intraventricular, deep Sylvain fissure, pineal region, intraparenchymal, or subcortical meningiomas. To the best of our knowledge, intraparenchymal meningioma with cerebriform pattern has never been reported. In this paper, we report a 34-year-old Chinese male patient who presented with paroxysmal headaches and progressive loss of vision for 10 months and blindness for 2 weeks. A thorough physical examination revealed loss of bilateral direct and indirect light reflex. No other relevant medical history and neurologic deficits were noted. Computed tomography and magnetic resonance imaging scans showed an irregular mass with a unique cerebriform pattern and extensive peritumoral edema in the parietal-occipital-temporal region of the right cerebral hemisphere. The initial diagnosis was lymphoma. Intraoperatively, the tumor was completely buried in a sulcus in the parietal-occipital-temporal region without connecting to the dura. The histological diagnosis was intracranial meningioma based on pathological examination. Therefore, when an unusual cerebriform growth pattern of a tumor is encountered, an intraparenchymal meningioma should be considered as a differential diagnosis. PMID:27752384

  5. Patterned Growth of Carbon Nanotubes or Nanofibers

    NASA Technical Reports Server (NTRS)

    Delzeit, Lance D.

    2004-01-01

    A method and apparatus for the growth of carbon nanotubes or nanofibers in a desired pattern has been invented. The essence of the method is to grow the nanotubes or nanofibers by chemical vapor deposition (CVD) onto a patterned catalyst supported by a substrate. The figure schematically depicts salient aspects of the method and apparatus in a typical application. A substrate is placed in a chamber that contains both ion-beam sputtering and CVD equipment. The substrate can be made of any of a variety of materials that include several forms of silicon or carbon, and selected polymers, metals, ceramics, and even some natural minerals and similar materials. Optionally, the substrate is first coated with a noncatalytic metal layer (which could be a single layer or could comprise multiple different sublayers) by ion-beam sputtering. The choice of metal(s) and thickness(es) of the first layer (if any) and its sublayers (if any) depends on the chemical and electrical properties required for subsequent deposition of the catalyst and the subsequent CVD of the carbon nanotubes. A typical first-sublayer metal is Pt, Pd, Cr, Mo, Ti, W, or an alloy of two or more of these elements. A typical metal for the second sublayer or for an undivided first layer is Al at a thickness .1 nm or Ir at a thickness .5 nm. Proper choice of the metal for a second sublayer of a first layer makes it possible to use a catalyst that is chemically incompatible with the substrate. In the next step, a mask having holes in the desired pattern is placed over the coated substrate. The catalyst is then deposited on the coated substrate by ion-beam sputtering through the mask. Optionally, the catalyst could be deposited by a technique other than sputtering and/or patterned by use of photolithography, electron- beam lithography, or another suitable technique. The catalytic metal can be Fe, Co, Ni, or an alloy of two or more of these elements, deposited to a typical thickness in the range from 0.1 to 20 nm.

  6. Shoot Growth Patterns of Young Loblolly Pine

    Treesearch

    William D. Boyer

    1970-01-01

    Most shoot elongation on Pinus taeda L. seedlings and saplings near Durham. North Carolina. was supplied by the lirst growth Ilush, which began about April 1 and ended in mid-May 1967. New growth per shoot declined with distance from the tree top. All leaders had three flushes and half had four. Variation in internode growth was dependent upon...

  7. Third trimester growth restriction patterns: individualized assessment using a fetal growth pathology score.

    PubMed

    Deter, Russell L; Lee, Wesley; Sangi-Haghpeykar, Haleh; Kingdom, John; Romero, Roberto

    2017-07-06

    To qualitatively and quantitatively characterize third trimester growth patterns in fetuses/neonates with growth restriction using Individualized Growth Assessment. Serial fetal size measurements from 73 fetuses with proven growth restriction were evaluated using a novel composite parameter, the Fetal Growth Pathology Score (FGPS1). Third trimester FGPS1 measurements plotted against fetal age were examined for patterns. Identified patterns were characterized using the four components of the FGP1 [head circumference (HC), abdominal circumference (AC), femur diaphysis length (FDL), estimated weight (EWT)]. A secondary characterization using age of onset, duration and magnitude of the growth abnormality process was also performed. Frequencies and magnitudes of abnormal values in different FGPS1 patterns were compared. Five growth restriction patterns were found in 70/73 (95.9%) of the cases, with progressive worsening [Pattern 1 (37.0%)] and abnormal growth identified only at last scan [Pattern 2 (27.4%)] being the most common. These two patterns were usually statistically different from each other and the other three with respect to size parameter abnormalities and abnormal growth process characteristics (MANOVA). Growth abnormalities in all parameters of the FGPS1 contributed to the five abnormality patterns although AC and EWT were most important. The age of onset, duration and magnitude were similar between patterns except for Pattern 2, which had a late onset and a short duration (GLM + contrasts). Our study represents the first detailed evaluation of third trimester growth restriction using methods that consider the growth potential of each fetus. Five distinctive and repetitive patterns were found, suggesting that fetal growth restriction evolves in different ways. Further research is needed to determine the relationships of these patterns to physiological/biochemical changes and adverse outcomes associated with growth restriction.

  8. The Growth Patterns of General Medical Achievement.

    ERIC Educational Resources Information Center

    Shen, Linjun

    This longitudinal study investigates the growth of medical achievement as a multilevel process and emphasizes the structure of the growth. Subjects were students in all 15 U.S. osteopathic medical schools, a total of 1,060 (78 percent of the 1987 osteopathic cohort). Students took appropriate portions of the National Board of Osteopathic Medical…

  9. Biochemical characterization and growth patterns of new yeast isolates.

    PubMed

    Djegui, Kadjogbé Y; Gachomo, Emma W; Hounhouigan, Djidjoho J; Kayodé, Adéchola P P; Kotchoni, Simeon O

    2014-08-01

    African sorghum opaque beers play a vital role in the diet of millions of consumers. In the current study we investigated the growth profiles of yeast strains isolated from kpete-kpete, a traditional starter used to produce tchoukoutou, an opaque sorghum beer in Benin. 10 yeast strains were isolated from sorghum beer starters and cultivated under both liquid and solid media for phenotypic growth characterization. All yeast isolates were able to grow both on solid and liquid media. Based on their growth profiles, the isolates were clustered into three groups: (i) the aggressive growth pattern (30%), (ii) the moderate growth pattern (50%), and (iii) the slow growth pattern (20%). Based on gene expression pattern, absorbance (A(600 nm)) and diameter of growth in both liquid and solid media respectively, yeast strains YK34, YK15 and YK48 were clustered in the first group, and referred to as the most aggressive growth strains, followed by group 2 (YK24, YK5, YK12, YK20, YK2) and group 3 (YK37, YK41). This growth pattern was confirmed by Invertase gene expression profiling of the yeasts showing group 1 with high level of Invertase gene expression followed by group 2 and group 3 respectively. Our results suggest that YK34, YK15 and YK48 and YK2 yeast strains constitute the best candidates in fermentation of sorghum beer production based on growth rate and assimilation of carbon and nitrogen sources.

  10. Dinosaurian growth patterns and rapid avian growth rates.

    PubMed

    Erickson, G M; Rogers, K C; Yerby, S A

    2001-07-26

    Did dinosaurs grow in a manner similar to extant reptiles, mammals or birds, or were they unique? Are rapid avian growth rates an innovation unique to birds, or were they inherited from dinosaurian precursors? We quantified growth rates for a group of dinosaurs spanning the phylogenetic and size diversity for the clade and used regression analysis to characterize the results. Here we show that dinosaurs exhibited sigmoidal growth curves similar to those of other vertebrates, but had unique growth rates with respect to body mass. All dinosaurs grew at accelerated rates relative to the primitive condition seen in extant reptiles. Small dinosaurs grew at moderately rapid rates, similar to those of marsupials, but large species attained rates comparable to those of eutherian mammals and precocial birds. Growth in giant sauropods was similar to that of whales of comparable size. Non-avian dinosaurs did not attain rates like those of altricial birds. Avian growth rates were attained in a stepwise fashion after birds diverged from theropod ancestors in the Jurassic period.

  11. Fast growth of graphene patterns by laser direct writing

    SciTech Connect

    Park, J. B.; Xiong, W.; Gao, Y.; Qian, M.; Xie, Z. Q.; Mitchell, M.; Zhou, Y. S.; Lu, Y. F.; Han, G. H.; Jiang, L.

    2011-03-21

    Rapid single-step fabrication of graphene patterns was developed using laser-induced chemical vapor deposition (LCVD). A laser beam irradiates a thin nickel foil in a CH{sub 4} and H{sub 2} environment to induce a local temperature rise, thereby allowing the direct writing of graphene patterns in precisely controlled positions at room temperature. Line patterns can be achieved with a single scan without pre- or postprocesses. Surprisingly, the growth rate is several thousand times faster than that of general CVD methods. The discovery and development of the LCVD growth process provide a route for the rapid fabrication of graphene patterns for various applications.

  12. Ordered Self-Similar Patterns in Anisotropic Stochastic Growth.

    PubMed

    Yao, Zhenwei; Olvera de la Cruz, Monica

    2016-07-07

    We propose an anisotropic stochastic growth model to rationalize the anisotropic self-assembly of supramolecules to form elongated two-dimensional ribbon structures in a recent experiment. The model exhibits distinct growth scenarios that are critically controlled by the ratio of the transverse and the longitudinal growth rate. In the regime of suppressed transverse growth, the model generates the experimentally observed elongated structures through layer-by-layer growing. We further observe the convergence of rough clusters toward smooth regular elliptic patterns by averaging over a number of independent growth processes. Remarkably, these resulting elliptic clusters are self-similar in each instantaneous moment in the growth process. Statistical analysis suggests that the realization of such ordered patterns does not rely on the delicate coordination of different parts in the cluster growth. The self-similarity phenomenon derived from this idealized model may have wider implications, notably in the designed clustering of various elementary building blocks with anisotropic interactions.

  13. Maternal Height and Child Growth Patterns

    PubMed Central

    Addo, O. Yaw; Stein, Aryeh D.; Fall, Caroline H.; Gigante, Denise P.; Guntupalli, Aravinda M.; Horta, Bernardo L.; Kuzawa, Christopher W.; Lee, Nanette; Norris, Shane A.; Prabhakaran, Poornima; Richter, Linda M.; Sachdev, Harshpal S.; Martorell, Reynaldo

    2013-01-01

    Objective To examine associations between maternal height and child growth during 4 developmental periods: intrauterine, birth to age 2 years, age 2 years to mid-childhood (MC), and MC to adulthood. Study design Pooled analysis of maternal height and offspring growth using 7630 mother–child pairs from 5 birth cohorts (Brazil, Guatemala, India, the Philippines, and South Africa). We used conditional height measures that control for collinearity in height across periods. We estimated associations between maternal height and offspring growth using multivariate regression models adjusted for household income, child sex, birth order, and study site. Results Maternal height was associated with birth weight and with both height and conditional height at each age examined. The strongest associations with conditional heights were for adulthood and 2 years of age. A 1-cm increase in maternal height predicted a 0.024 (95% CI: 0.021-0.028) SD increase in offspring birth weight, a 0.037 (95% CI: 0.033-0.040) SD increase in conditional height at 2 years, a 0.025 (95% CI: 0.021-0.029 SD increase in conditional height in MC, and a 0.044 (95% CI: 0.040-0.048) SD increase in conditional height in adulthood. Short mothers (<150.1 cm) were more likely to have a child who was stunted at 2 years (prevalence ratio = 3.20 (95% CI: 2.80-3.60) and as an adult (prevalence ratio = 4.74, (95% CI: 4.13-5.44). There was no evidence of heterogeneity by site or sex. Conclusion Maternal height influences offspring linear growth over the growing period. These influences likely include genetic and non-genetic factors, including nutrition-related intergenerational influences on growth that prevent the attainment of genetic height potential in low- and middle-income countries. PMID:23477997

  14. Hair growth cycles and wave patterns in "nude" mice.

    PubMed

    Eaton, G J

    1976-09-01

    Hair growth cycles and waves were studied through five generations of hair growth in C57BL/6Icr "nude" mice. One group of nudes received thymus grafts, a second group was composed of athymid nudes and a third consisted of heterozygous (nu/&) haired littermates. The results showed that hair growth cycles and wave patterns were essentially the same in thymus-restored nudes and athymic nudes which indicated that thymus did not play a role in these phenomena. The time interval between hair cycles was considerably shorter in both groups of nude mice as compared to heterozygotes (nu/&). Finally, the hair growth wave pattern in nude mice did not change throughout the generation of hair growth whereas profound changes in wave patterns were observed in heterozygous (nu/&) littermates.

  15. The relationship between growth and pattern formation

    PubMed Central

    Bryant, Susan V.

    2016-01-01

    Abstract Successful development depends on the creation of spatial gradients of transcription factors within developing fields, and images of graded distributions of gene products populate the pages of developmental biology journals. Therefore the challenge is to understand how the graded levels of intracellular transcription factors are generated across fields of cells. We propose that transcription factor gradients are generated as a result of an underlying gradient of cell cycle lengths. Very long cell cycles will permit accumulation of a high level of a gene product encoded by a large transcription unit, whereas shorter cell cycles will permit progressively fewer transcripts to be completed due to gating of transcription by the cell cycle. We also propose that the gradients of cell cycle lengths are generated by gradients of extracellular morphogens/growth factors. The model of cell cycle gated transcriptional regulation brings focus back to the functional role of morphogens as cell cycle regulators, and proposes a specific and testable mechanism by which morphogens, in their roles as growth factors (how they were originally discovered), also determine cell fate. PMID:27499882

  16. Lift-up growth of aligned carbon nanotube patterns

    NASA Astrophysics Data System (ADS)

    Wei, Bingqing; Zhang, Z. J.; Ramanath, G.; Ajayan, P. M.

    2000-11-01

    The fabrication of three-dimensional networks of carbon nanotubes with controlled orientation will be essential for building large-scale functional devices integrated with microelectronics circuits. We describe here our recent work on the controlled synthesis of vertically aligned carbon-nanotube patterns, grown under patterned metal layers on Si substrates by combining chemical-vapor deposition and conventional lithography. We show that metal patterns are lifted up by vertically aligned nanotubes during growth. This lift-up growth links the thin-film metal patterns and the Si substrate via nanotube assemblies, giving the possibility of creating nanotube architectures in three dimensions. The possible scenarios of the growth of aligned nanotube films leading to the lift up of the metal films are discussed.

  17. Daylength mediated control of seasonal growth patterns in perennial trees.

    PubMed

    Petterle, Anna; Karlberg, Anna; Bhalerao, Rishikesh P

    2013-06-01

    Daylength is a key regulator of seasonal growth patterns in perennial trees in temperate regions. Cessation of growth is induced by short day signal in these trees before the advent of winter and constitutes a major adaptive developmental program. In this review, we report on the recent progress made in identifying the molecular mechanisms that underlie the daylength mediated control of seasonal growth in perennial trees. A major finding that has emerged from the analysis of this process is that the regulation of growth cessation in perennial trees and flowering time by daylength in annuals such as Arabidopsis thaliana involves identical signalling components.

  18. Author Name Disambiguation for PubMed.

    PubMed

    Liu, Wanli; Islamaj Doğan, Rezarta; Kim, Sun; Comeau, Donald C; Kim, Won; Yeganova, Lana; Lu, Zhiyong; Wilbur, W John

    2014-04-01

    Log analysis shows that PubMed users frequently use author names in queries for retrieving scientific literature. However, author name ambiguity may lead to irrelevant retrieval results. To improve the PubMed user experience with author name queries, we designed an author name disambiguation system consisting of similarity estimation and agglomerative clustering. A machine-learning method was employed to score the features for disambiguating a pair of papers with ambiguous names. These features enable the computation of pairwise similarity scores to estimate the probability of a pair of papers belonging to the same author, which drives an agglomerative clustering algorithm regulated by 2 factors: name compatibility and probability level. With transitivity violation correction, high precision author clustering is achieved by focusing on minimizing false-positive pairing. Disambiguation performance is evaluated with manual verification of random samples of pairs from clustering results. When compared with a state-of-the-art system, our evaluation shows that among all the pairs the lumping error rate drops from 10.1% to 2.2% for our system, while the splitting error rises from 1.8% to 7.7%. This results in an overall error rate of 9.9%, compared with 11.9% for the state-of-the-art method. Other evaluations based on gold standard data also show the increase in accuracy of our clustering. We attribute the performance improvement to the machine-learning method driven by a large-scale training set and the clustering algorithm regulated by a name compatibility scheme preferring precision. With integration of the author name disambiguation system into the PubMed search engine, the overall click-through-rate of PubMed users on author name query results improved from 34.9% to 36.9%.

  19. Secretory pattern and regulatory mechanism of growth hormone in cattle.

    PubMed

    Kasuya, Etsuko

    2016-02-01

    The ultradian rhythm of growth hormone (GH) secretion has been known in several animal species for years and has recently been observed in cattle. Although the physiological significance of the rhythm is not yet fully understood, it appears essential for normal growth. In this review, previous studies concerning the GH secretory pattern in cattle, including its ultradian rhythm, are introduced and the regulatory mechanism is discussed on the basis of recent findings.

  20. Effects of Growth and Mutation on Pattern Formation in Tissues

    PubMed Central

    Mengel Pers, Benedicte; Krishna, Sandeep; Chakraborty, Sagar; Pigolotti, Simone; Sekara, Vedran; Semsey, Szabolcs; Jensen, Mogens H.

    2012-01-01

    In many developing tissues, neighboring cells enter different developmental pathways, resulting in a fine-grained pattern of different cell states. The most common mechanism that generates such patterns is lateral inhibition, for example through Delta-Notch coupling. In this work, we simulate growth of tissues consisting of a hexagonal arrangement of cells laterally inhibiting their neighbors. We find that tissue growth by cell division and cell migration tends to produce ordered patterns, whereas lateral growth leads to disordered, patchy patterns. Ordered patterns are very robust to mutations (gene silencing or activation) in single cells. In contrast, mutation in a cell of a disordered tissue can produce a larger and more widespread perturbation of the pattern. In tissues where ordered and disordered patches coexist, the perturbations spread mostly at boundaries between patches. If cell division occurs on time scales faster than the degradation time, disordered patches will appear. Our work suggests that careful experimental characterization of the disorder in tissues could pinpoint where and how the tissue is susceptible to large-scale damage even from single cell mutations. PMID:23144963

  1. Lateral OMVPE growth of GaAs on patterned substrates

    NASA Astrophysics Data System (ADS)

    Reichert, W.; Cohen, R. M.

    2000-12-01

    GaAs was grown on patterned <1 0 0> on- and off-axis GaAs substrates by organometallic vapor-phase epitaxy (OMVPE). Patterned mesas were observed to change shape because lateral growth rates varied by more than an order of magnitude in different crystallographic directions. For this study, misoriented GaAs (1 0 0) wafers were polished 3° toward the nearest [1 1 0] or [1 1 1] family of directions, and 320 nm high cross-shaped mesas were fabricated. OMVPE growth was performed between 550°C and 650°C for 1 h at a vertical growth rate of approximately 1.3 μm/h. Atomic force microscopy showed that three effects have a powerful influence on lateral growth initiated at mesa sidewalls. First, the symmetry of the dominant surface reconstruction has a major effect on the diffusion of Ga adatoms. Rapid Ga diffusion occurs along the <0 1 1>-<0-1-1> axis in OMVPE, or the perpendicular <0-1 1>-<0 1-1> axis in molecular beam epitaxy, and appears to be a result of the different surface reconstructions which exist in the two growth ambients. Second, misorientation of the wafer causes a growth asymmetry as Ga adatoms move preferentially from high-to-low terraces. When terrace steps descend toward a mesa wall, rapid lateral growth away from the wall is always observed. When terrace steps descend away from a mesa wall, little lateral growth occurs and even reduced vertical growth may be observed. When the misorientation and reconstruction symmetries align, the surface acts like an atomic diode and the rapid lateral growth can exceed the vertical growth rate by more than an order of magnitude. Third, on misoriented substrates, step bunching increases with increasing temperature, and this can lead to significant changes in the original shape of a mesa. A growth model is presented which relates the lateral growth rate in different crystallographic directions to the substrate misorientation, the growth temperature, and the partial pressure of As during growth. It is also shown that

  2. Recent growth of conifer species of western North America: Assessing spatial patterns of radial growth trends

    USGS Publications Warehouse

    McKenzie, D.; Hessl, Amy E.; Peterson, D.L.

    2001-01-01

    We explored spatial patterns of low-frequency variability in radial tree growth among western North American conifer species and identified predictors of the variability in these patterns. Using 185 sites from the International Tree-Ring Data Bank, each of which contained 10a??60 raw ring-width series, we rebuilt two chronologies for each site, using two conservative methods designed to retain any low-frequency variability associated with recent environmental change. We used factor analysis to identify regional low-frequency patterns in site chronologies and estimated the slope of the growth trend since 1850 at each site from a combination of linear regression and time-series techniques. This slope was the response variable in a regression-tree model to predict the effects of environmental gradients and species-level differences on growth trends. Growth patterns at 27 sites from the American Southwest were consistent with quasi-periodic patterns of drought. Either 12 or 32 of the 185 sites demonstrated patterns of increasing growth between 1850 and 1980 A.D., depending on the standardization technique used. Pronounced growth increases were associated with high-elevation sites (above 3000 m) and high-latitude sites in maritime climates. Future research focused on these high-elevation and high-latitude sites should address the precise mechanisms responsible for increased 20th century growth.

  3. An efficient, versatile and scalable pattern growth approach to mine frequent patterns in unaligned protein sequences.

    PubMed

    Ye, Kai; Kosters, Walter A; Ijzerman, Adriaan P

    2007-03-15

    Pattern discovery in protein sequences is often based on multiple sequence alignments (MSA). The procedure can be computationally intensive and often requires manual adjustment, which may be particularly difficult for a set of deviating sequences. In contrast, two algorithms, PRATT2 (http//www.ebi.ac.uk/pratt/) and TEIRESIAS (http://cbcsrv.watson.ibm.com/) are used to directly identify frequent patterns from unaligned biological sequences without an attempt to align them. Here we propose a new algorithm with more efficiency and more functionality than both PRATT2 and TEIRESIAS, and discuss some of its applications to G protein-coupled receptors, a protein family of important drug targets. In this study, we designed and implemented six algorithms to mine three different pattern types from either one or two datasets using a pattern growth approach. We compared our approach to PRATT2 and TEIRESIAS in efficiency, completeness and the diversity of pattern types. Compared to PRATT2, our approach is faster, capable of processing large datasets and able to identify the so-called type III patterns. Our approach is comparable to TEIRESIAS in the discovery of the so-called type I patterns but has additional functionality such as mining the so-called type II and type III patterns and finding discriminating patterns between two datasets. The source code for pattern growth algorithms and their pseudo-code are available at http://www.liacs.nl/home/kosters/pg/.

  4. Acta informatica medica is indexed in pubmed and archived in pubmed central.

    PubMed

    Masic, Izet

    2013-03-01

    Acta Informatica Medica journal has been accepted for archiving in PubMed Central from 2011 onward. The journal started in 1993 as the official journal of the Society for Medical Informatics of Bosnia and Herzegovina. During the last 3 years, Acta Informatica Medica has een included in almost all prestigious online databases, including PubMed, Scopus and EMBASE. The 20th volume of the journal is fully international, with papers from 18 countries.

  5. Acta Informatica Medica Is Indexed In Pubmed And Archived In Pubmed Central

    PubMed Central

    Masic, Izet

    2013-01-01

    Acta Informatica Medica journal has been accepted for archiving in PubMed Central from 2011 onward. The journal started in 1993 as the official journal of the Society for Medical Informatics of Bosnia and Herzegovina. During the last 3 years, Acta Informatica Medica has een included in almost all prestigious online databases, including PubMed, Scopus and EMBASE. The 20th volume of the journal is fully international, with papers from 18 countries. PMID:23572852

  6. Cytometric patterns reveal growth states of Shewanella putrefaciens

    PubMed Central

    Melzer, Susanne; Winter, Gudrun; Jäger, Kathrin; Hübschmann, Thomas; Hause, Gerd; Syrowatka, Frank; Harms, Hauke; Tárnok, Attila; Müller, Susann

    2015-01-01

    Bacterial growth is often difficult to estimate beyond classical cultivation approaches. Low cell numbers, particles or coloured and dense media may disturb reliable growth assessment. Further difficulties appear when cells are attached to surfaces and detachment is incomplete. Therefore, flow cytometry was tested and used for analysis of bacterial growth on the single-cell level. Shewanella putrefaciens was cultivated as a model organism in planktonic or biofilm culture. Materials of smooth and rough surfaces were used for biofilm cultivation. Both aerobic and anaerobic as well as feast and famine conditions were applied. Visualization of growth was also done using Environmental Scanning and Phase Contrast Microscopy. Bioinformatic tools were applied for data interpretation. Cytometric proliferation patterns based on distributions of DNA contents per cell corresponded distinctly to the various lifestyles, electron acceptors and substrates tested. Therefore, cell cycling profiles of S. putrefaciens were found to mirror growth conditions. The cytometric patterns were consistently detectable with exception of some biofilm types whose resolution remained challenging. Corresponding heat maps proved to be useful for clear visualization of growth behaviour under all tested conditions. Therefore, flow cytometry in combination with bioinformatic tools proved to be powerful means to determine various growth states of S. putrefaciens, even in constrained environments. The approach is universal and will also be applicable for other bacterial species. PMID:25185955

  7. Cytometric patterns reveal growth states of Shewanella putrefaciens.

    PubMed

    Melzer, Susanne; Winter, Gudrun; Jäger, Kathrin; Hübschmann, Thomas; Hause, Gerd; Syrowatka, Frank; Harms, Hauke; Tárnok, Attila; Müller, Susann

    2015-05-01

    Bacterial growth is often difficult to estimate beyond classical cultivation approaches. Low cell numbers, particles or coloured and dense media may disturb reliable growth assessment. Further difficulties appear when cells are attached to surfaces and detachment is incomplete. Therefore, flow cytometry was tested and used for analysis of bacterial growth on the single-cell level. Shewanella putrefaciens was cultivated as a model organism in planktonic or biofilm culture. Materials of smooth and rough surfaces were used for biofilm cultivation. Both aerobic and anaerobic as well as feast and famine conditions were applied. Visualization of growth was also done using Environmental Scanning and Phase Contrast Microscopy. Bioinformatic tools were applied for data interpretation. Cytometric proliferation patterns based on distributions of DNA contents per cell corresponded distinctly to the various lifestyles, electron acceptors and substrates tested. Therefore, cell cycling profiles of S. putrefaciens were found to mirror growth conditions. The cytometric patterns were consistently detectable with exception of some biofilm types whose resolution remained challenging. Corresponding heat maps proved to be useful for clear visualization of growth behaviour under all tested conditions. Therefore, flow cytometry in combination with bioinformatic tools proved to be powerful means to determine various growth states of S. putrefaciens, even in constrained environments. The approach is universal and will also be applicable for other bacterial species. © 2014 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  8. SPELLING CORRECTION IN THE PUBMED SEARCH ENGINE.

    PubMed

    Wilbur, W John; Kim, Won; Xie, Natalie

    2006-11-01

    It is known that users of internet search engines often enter queries with misspellings in one or more search terms. Several web search engines make suggestions for correcting misspelled words, but the methods used are proprietary and unpublished to our knowledge. Here we describe the methodology we have developed to perform spelling correction for the PubMed search engine. Our approach is based on the noisy channel model for spelling correction and makes use of statistics harvested from user logs to estimate the probabilities of different types of edits that lead to misspellings. The unique problems encountered in correcting search engine queries are discussed and our solutions are outlined.

  9. SPELLING CORRECTION IN THE PUBMED SEARCH ENGINE

    PubMed Central

    Wilbur, W. John; Kim, Won; Xie, Natalie

    2007-01-01

    It is known that users of internet search engines often enter queries with misspellings in one or more search terms. Several web search engines make suggestions for correcting misspelled words, but the methods used are proprietary and unpublished to our knowledge. Here we describe the methodology we have developed to perform spelling correction for the PubMed search engine. Our approach is based on the noisy channel model for spelling correction and makes use of statistics harvested from user logs to estimate the probabilities of different types of edits that lead to misspellings. The unique problems encountered in correcting search engine queries are discussed and our solutions are outlined. PMID:18080004

  10. Elevation Pattern in Growth Coherency on the Southeastern Tibetan Plateau

    PubMed Central

    Lyu, Lixin; Deng, Xu; Zhang, Qi-Bin

    2016-01-01

    It is generally expected that inter-annual changes in radial growth among trees would be similar to the increase in altitude due to the limitation of increasingly harsher climatic factors. Here, we examine whether this pattern exists in alpine forests on the southeastern Tibetan Plateau. Increment cores were collected from mature trees at the lower, middle and upper limits of balfour spruce (Picea likiangensis var. balfouriana (Rehd. et Wils.) Hillier ex Slsvin) forests at the Buze and Yela Mountains in Basu County, Changdu Prefecture of Tibet, China. The treeline elevations are 4320 m and 4510 m a.s.l. for Buze and Yela, respectively. Tree-ring widths were measured, crossdated, and detrended to obtain a sequence of ring-width indices for each individual sample. Annual growth rate, climate sensitivity, growth-climate relationships, and growth synchrony among trees were calculated and compared across altitudes. In Buze Mountain, the annual growth rate of trees has no significant difference across altitudes. The mean sensitivity of trees is lower at the treelines than at lower elevations. Tree growth has stronger correlation with winter temperature at upper elevations than at lower elevations, has significant correlation with moisture, not temperature, in the growing season, and the growth response to moisture is lower at the treeline than at lower elevations. The correlation among individual tree-ring sequences is lower at the treeline than at sites at lower elevation. In Yela Mountain, the characterisitics of annual growth rate, mean sensitivity, tree growth-climate relationships, and inter-serial correlation are similar to those in Buze, but their differences along altitudinal gradients are less significant as those in Buze. Our data do not support the general expectation of growth convergence among individuals with increasing altitude. We conclude that individual heterogeneity and microhabitat diversity are important features for treeline trees that may dampen

  11. Growth patterns of patients with 1p36 deletion syndrome.

    PubMed

    Sangu, Noriko; Shimojima, Keiko; Shimada, Shino; Ando, Tomohiro; Yamamoto, Toshiyuki

    2014-05-01

    1p36 deletion syndrome is one of the most common subtelomeric deletion syndromes. Obesity is frequently observed in patients with this syndrome. Thus, it is important to evaluate the growth status of an individual patient. For this purpose, we accumulated recorded growth data from 44 patients with this syndrome and investigated the growth patterns of patients. Most of the patients showed weight parameters within normal limits, whereas a few of these patients showed intrauterine growth delay and microcephaly. The length of the patients after birth was under the 50th centile in most patients. Many patients showed poor weight gain after birth, and only two female patients were overweight. These findings indicate two different phenotypes of the 1p36 deletion syndrome. The overweight patients with 1p36 deletion started excessive weight gain after two years of life. This characteristic of the patients with 1p36 deletion syndrome is similar to Prader-Willi syndrome.

  12. Geological pattern formation by growth and dissolution in aqueous systems

    SciTech Connect

    Paul Meakin

    2010-03-01

    Although many geological processes take place on time scales that are very long compared with the human experience, essentially all geological processes, fast or slow, are far from equilibrium processes. Surprisingly often, geological processes lead to the formation of quite simple and distinctive patterns, which hint at an underlying simplicity in many complex geological systems.. The ability to predict the seasons was critically important to early human society, and Halley’s prediction of the return of the comet that bears his name is still considered to be a scientific milestone. Spatial patterns have also attracted attention because of their aesthetic appeal, which depends in subtle ways on a combination of regularity and irregularity. In recent decades, rapid growth in the capabilities of digital computers has facilitated the simulation of pattern formation processes, and computer simulations have become an important tool for evaluating theoretical concepts and for scientific discovery. Computer technology in combination with other technologies such as high resolution digital cameras, scanning microprobes (atomic force microscopy AFM), confocal microscopy, and scanning tunneling microscopy (STM), for example) has facilitated the quantitative characterization of patterns over a wide range of scales and has enabled rapid advances in our ability to understand the links between large scale pattern formation and microscopic processes. The ability to quantitatively characterize patterns is important because it enables a more rigorous comparison between the predictions of computer models and real world patterns and their formation.In some cases, the idea that patterns with a high degree of regularity have simple origins appears to be justified, but in other cases, such as the formation of almost perfectly circular stone rings due to freeze-thaw cycles simple patterns appear to be the consequence of quite complex processes. In other cases, it has been shown that

  13. The peptide growth factor, phytosulfokine, attenuates pattern-triggered immunity.

    PubMed

    Igarashi, Daisuke; Tsuda, Kenichi; Katagiri, Fumiaki

    2012-07-01

    Pattern-triggered immunity (PTI) is triggered by recognition of elicitors called microbe-associated molecular patterns (MAMPs). Although immune responses may provide good protection of plants from pathogen attack, excessive immune responses have negative impacts on plant growth and development. Thus, a good balance between positive and negative effects on the immune signaling network is important for plant fitness. However, little information is known about the molecular mechanisms that are involved in attenuation of PTI. Here, we describe a growth-promoting peptide hormone, phytosulfokine (PSK), as attenuating PTI signaling in Arabidopsis. This research was motivated by the observation that expression of the PSK Receptor 1 (PSKR1) gene was induced by MAMP treatment. Plants homozygous for pskr1 T-DNA insertions showed enhanced defense gene expression and seedling growth inhibition triggered by MAMPs. The pskr1 plants also showed enhanced PTI against the bacterial pathogen Pseudomonas syringae. These results indicate that the PSKR-mediated signaling attenuates immune responses. Tyrosyl protein sulfotransferase (TPST) is an enzyme required for production of the mature sulfated PSK. Like pskr1 mutants, a tpst T-DNA insertion line exhibited enhanced MAMP-triggered seedling growth inhibition, which was suppressed by exogenous application of PSK. Thus, PSK signaling mediated by PSKR1 attenuates PTI but stimulates growth.

  14. Analysis of the growth pattern of a dermoid cyst.

    PubMed

    Fanous, Andrew A; Gupta, Puneet; Li, Veetai

    2014-12-01

    Dermoid cysts are rare lesions of the CNS with a slow rate of growth. For this reason, they are rarely discovered during infancy. Although benign, these cysts may be associated with devastating complications due to mass effect or meningitis. The discovery of completely asymptomatic dermoid cysts in the pediatric population is exceedingly rare; however, correct and prompt diagnosis is crucial for early surgical treatment to minimize morbidity and mortality. The authors report the unique case of a posterior fossa dermoid cyst discovered in a 5-month-old girl and monitored for 2.5 years with serial imaging studies before performing a resection. The imaging characteristics of dermoid cysts are reviewed, and the challenges associated with the radiographic diagnosis of such lesions are discussed. Analyzing the growth of this particular cyst on MRI allowed comment, for the first time to the authors' knowledge, regarding the growth rate of dermoid cysts. Unlike true tumors, which grow in an exponential pattern, the dermoid cyst in the reported case exhibited a linear growth pattern. The increase in volume followed the classic appearance of a cuboid sequence, which is also consistent with linear growth in all 3 dimensions.

  15. Nucleation and crystal growth in laser patterned lines in glasses

    NASA Astrophysics Data System (ADS)

    Komatsu, Takayuki; Honma, Tsuyoshi

    2016-07-01

    Laser-induced crystallization is a new method for the design and control of the crystallization of glasses and opens a new door in the study of nucleation and crystal growth in glasses. Nonlinear optical Sm-doped -BaB2O4 (-BBO) crystal lines were patterned by continuous wave Yb:YVO4 fiber laser (wavelength 1080 nm) in 8Sm2O3-42BaO-50B2O3 glass as an example, and nucleation and crystal growth behaviors in the laser-patterned bending and crossing lines were examined. It was confirmed that the growth of c-axis oriented -BBO crystals follows along the laser scanning direction even if laser scanning direction changes. The model of self-organized homo-epitaxial crystal growth was demonstrated for the orientation of -BBO crystals at the crossing point of two lines, in which the first crystal line at the crossing point acts as nucleation site for the second crystal line. This study proposes a new crystal growth technology.

  16. Growth Anisotropy and Pattern Formation in Metal Epitaxy

    NASA Astrophysics Data System (ADS)

    Jorritsma, Louis C.; Bijnagte, Matthieu; Rosenfeld, Georg; Poelsema, Bene

    1997-02-01

    Evidence for the formation of growth induced, ordered checkerboardlike arrangements of mesas has been obtained. These patterns develop on a metal substrate with square symmetry after deposition of tens of monolayers. Its origin is traced back to laterally anisotropic advance rates of island edges in combination with slope selection. The foundation for the mesa arrangement is already laid just after coalescence of the adatom islands in the first monolayer. The results are exemplified in a high resolution surface diffraction study for the growth of Cu on Cu(001).

  17. Nucleation and growth of CVD diamond films on patterned substrates

    SciTech Connect

    Monteiro, Othon R.; Liu, Hongbin

    2002-12-20

    The interest in using CVD diamond in the fabrication of microelectro-mechanical components has steadily increased over the last few years. Typical technology for manufacturing such components involves the use of molds patterned in silicon or silicon dioxide, which are filled by diamond deposition. The degree of conformality of the CVD film and the characteristics of the diamond-substrate interface becomes critical for the successful fabrication and performance of such devices. We have investigated the growth of CVD diamond films on patterned substrates using a microwave plasma assisted deposition reactor. In particular the use of seed layers to enhance nucleation on horizontal and vertical walls as well as to promote complete filling of narrow trenches is investigated. Scanning electron microscopy is used to characterize the nucleation and growth of the diamond films.

  18. A synthesis of radial growth patterns preceding tree mortality.

    PubMed

    Cailleret, Maxime; Jansen, Steven; Robert, Elisabeth M R; Desoto, Lucía; Aakala, Tuomas; Antos, Joseph A; Beikircher, Barbara; Bigler, Christof; Bugmann, Harald; Caccianiga, Marco; Čada, Vojtěch; Camarero, Jesus J; Cherubini, Paolo; Cochard, Hervé; Coyea, Marie R; Čufar, Katarina; Das, Adrian J; Davi, Hendrik; Delzon, Sylvain; Dorman, Michael; Gea-Izquierdo, Guillermo; Gillner, Sten; Haavik, Laurel J; Hartmann, Henrik; Hereş, Ana-Maria; Hultine, Kevin R; Janda, Pavel; Kane, Jeffrey M; Kharuk, Vyacheslav I; Kitzberger, Thomas; Klein, Tamir; Kramer, Koen; Lens, Frederic; Levanic, Tom; Linares Calderon, Juan C; Lloret, Francisco; Lobo-Do-Vale, Raquel; Lombardi, Fabio; López Rodríguez, Rosana; Mäkinen, Harri; Mayr, Stefan; Mészáros, Ilona; Metsaranta, Juha M; Minunno, Francesco; Oberhuber, Walter; Papadopoulos, Andreas; Peltoniemi, Mikko; Petritan, Any M; Rohner, Brigitte; Sangüesa-Barreda, Gabriel; Sarris, Dimitrios; Smith, Jeremy M; Stan, Amanda B; Sterck, Frank; Stojanović, Dejan B; Suarez, Maria L; Svoboda, Miroslav; Tognetti, Roberto; Torres-Ruiz, José M; Trotsiuk, Volodymyr; Villalba, Ricardo; Vodde, Floor; Westwood, Alana R; Wyckoff, Peter H; Zafirov, Nikolay; Martínez-Vilalta, Jordi

    2017-04-01

    Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan-continental tree-ring width database from sites where both dead and living trees were sampled (2970 dead and 4224 living trees from 190 sites, including 36 species), and compared early and recent growth rates between trees that died and those that survived a given mortality event. We observed a decrease in radial growth before death in ca. 84% of the mortality events. The extent and duration of these reductions were highly variable (1-100 years in 96% of events) due to the complex interactions among study species and the source(s) of mortality. Strong and long-lasting declines were found for gymnosperms, shade- and drought-tolerant species, and trees that died from competition. Angiosperms and trees that died due to biotic attacks (especially bark-beetles) typically showed relatively small and short-term growth reductions. Our analysis did not highlight any universal trade-off between early growth and tree longevity within a species, although this result may also reflect high variability in sampling design among sites. The intersite and interspecific variability in growth patterns before mortality provides valuable information on the nature of the mortality process, which is consistent with our understanding of the physiological mechanisms leading to mortality. Abrupt changes in growth immediately before death can be associated with generalized hydraulic failure and/or bark-beetle attack, while long-term decrease in growth may be associated with a gradual decline in hydraulic performance coupled with depletion in carbon reserves. Our results imply that growth-based mortality algorithms may be a powerful tool for predicting gymnosperm mortality induced by chronic stress, but not necessarily so for angiosperms and in case of intense drought or

  19. A synthesis of radial growth patterns preceding tree mortality

    USGS Publications Warehouse

    Cailleret, Maxime; Jansen, Steven; Robert, Elisabeth M.R.; Desoto, Lucia; Aakala, Tuomas; Antos, Joseph A.; Beikircher, Barbara; Bigler, Christof; Bugmann, Harald; Caccianiga, Marco; Cada, Vojtech; Camarero, Jesus J.; Cherubini, Paolo; Cochard, Herve; Coyea, Marie R.; Cufar, Katarina; Das, Adrian J.; Davi, Hendrik; Delzon, Sylvain; Dorman, Michael; Gea-Izquierdo, Guillermo; Gillner, Sten; Haavik, Laurel J.; Hartmann, Henrik; Heres, Ana-Maria; Hultine, Kevin R.; Janda, Pavel; Kane, Jeffrey M.; Kharuk, Vyacheslav I.; Kitzberger, Thomas; Klein, Tamir; Kramer, Koen; Lens, Frederic; Levanic, Tom; Calderon, Juan C. Linares; Lloret, Francisco; Lobo-Do-Vale, Raquel; Lombardi, Fabio; Lopez Rodriguez, Rosana; Makinen, Harri; Mayr, Stefan; Meszaros, IIona; Metsaranta, Juha M.; Minunno, Francesco; Oberhuber, Walter; Papadopoulos, Andreas; Peltoniemi, Mikko; Petritan, Any M.; Rohner, Brigitte; Sanguesa-Barreda, Gabriel; Sarris, Dimitrios; Smith, Jeremy M.; Stan, Amanda B.; Sterck, Frank; Stojanovic, Dejan B.; Suarez, Maria L.; Svoboda, Miroslav; Tognetti, Roberto; Torres-Ruiz, Jose M.; Trotsiuk, Volodymyr; Villalba, Ricardo; Vodde, Floor; Westwood, Alana R.; Wyckoff, Peter H.; Zafirov, Nikolay; Martinez-Vilalta, Jordi

    2017-01-01

    Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan-continental tree-ring width database from sites where both dead and living trees were sampled (2970 dead and 4224 living trees from 190 sites, including 36 species), and compared early and recent growth rates between trees that died and those that survived a given mortality event. We observed a decrease in radial growth before death in ca. 84% of the mortality events. The extent and duration of these reductions were highly variable (1–100 years in 96% of events) due to the complex interactions among study species and the source(s) of mortality. Strong and long-lasting declines were found for gymnosperms, shade- and drought-tolerant species, and trees that died from competition. Angiosperms and trees that died due to biotic attacks (especially bark-beetles) typically showed relatively small and short-term growth reductions. Our analysis did not highlight any universal trade-off between early growth and tree longevity within a species, although this result may also reflect high variability in sampling design among sites. The intersite and interspecific variability in growth patterns before mortality provides valuable information on the nature of the mortality process, which is consistent with our understanding of the physiological mechanisms leading to mortality. Abrupt changes in growth immediately before death can be associated with generalized hydraulic failure and/or bark-beetle attack, while long-term decrease in growth may be associated with a gradual decline in hydraulic performance coupled with depletion in carbon reserves. Our results imply that growth-based mortality algorithms may be a powerful tool for predicting gymnosperm mortality induced by chronic stress, but not necessarily so for angiosperms and in case of intense drought or

  20. Spatial patterns of cyanobacterial mat growth on sand ripples

    NASA Astrophysics Data System (ADS)

    Mariotti, G.; Klepac-Ceraj, V.; Perron, J. T.; Bosak, T.

    2016-02-01

    Photosynthetic microbial mats produce organic matter, cycle nutrients, bind pollutants and stabilize sediment in sandy marine environments. Here, we investigate the influence of bedforms and wave motion on the growth rate, composition and spatial variability of microbial mats by growing cyanobacterial mats on a rippled bed of carbonate sand in a wave tank. The tank was forced with an oscillatory flow with velocities below the threshold for sediment motion yet able to induce a porewater flow within the sediment. Different spatial patterns developed in mats depending on the initial biochemistry of the water medium. When growing in a medium rich in nitrogen, phosphorous and micronutrients, mats grew faster on ripple troughs than on ripple crests. After two months, mats covered the bed surface uniformly, and the microbial communities on the crests and in the troughs had similar compositions. Differences in bed shear stress and nutrient availability between crests and troughs were not able to explain the faster growth in the troughs. We hypothesize that this growth pattern is due to a "strainer" effect, i.e. the suspended bacteria from the inoculum were preferentially delivered to troughs by the wave-induced porewater flow. In the experiments initiated in a medium previously used up by a microbial mat and thus depleted in nutrients, mats grew preferentially on the ripple crests. This spatial pattern persisted for nearly two years, and the microbial composition on troughs and crests was different. We attribute this pattern to the upwelling of porewater in the crests, which increased the delivery of nutrients from sediment to the cyanobacteria on the bed surface. Thus, the macroscopic patterns formed by photosynthetic microbial mats on sand ripples may be used to infer whether mats are nutrient-limited and whether they are recently colonized or older than a month.

  1. Cooperativity and cluster growth patterns in acetonitrile: a DFT study.

    PubMed

    Remya, Karunakaran; Suresh, Cherumuttathu H

    2014-05-05

    Cooperativity in intermolecular interactions and cluster growth patterns of acetonitrile has been studied using M06L density functional theory. Cyclic, ladder-type, stacked, cross-stacked, and mixed patterns are studied. Total interaction energy (E(int)) and interaction energy per monomer (E(m)) show maximum stability and cooperativity in stacked clusters followed by cross-stacked ones. As cluster size increased, magnitude of E(m) showed significant increase. Compared to E(m) of dimer (-2.97 kcal/mol), the increase is 2.6-fold for 27mer. Higher stabilization in larger clusters is attributed to strong cooperativity in intermolecular C-H···N and dipolar interactions. Enhanced cooperativity in stacked structures is supported by atoms-in-molecule electron density (ρ) data. Sum of ρ at intermolecular bond critical points is the highest for stacked clusters. Further, area of negative-valued molecular electrostatic potential is linearly related with E(int) and showed the lowest value in stacked followed by cross-stacked clusters, indicating maximum utilization of lone pair density and maximum cooperativity in such growth patterns. A red shift in the average C-N stretching frequencies with increase in the number of monomers and its direct correlation with E(int) in stacked clusters also supported their stability. Further, two known crystal patterns of acetonitrile (α and β) with 16 monomers are optimized and compared with the most stable hexadecamer pattern and are found to show lower values for E(int) and E(m) compared to the latter. Based on this result, we predict the existence of a third crystal pattern for acetonitrile which will be more ordered and more stable than α and β forms.

  2. Growth patterns and the use of growth hormone in the mucopolysaccharidoses

    PubMed Central

    Polgreen, L.E.; Miller, B.S.

    2010-01-01

    Short stature is characteristic of patients with mucopolysaccharidosis (MPS) diseases. For children with skeletal dysplasias, such as MPS, it is important to know the natural history of growth. An understanding of the natural growth pattern in each MPS disease provides a measurement to which treatments can be compared, as well as data which can help families and providers make individualized decisions about growth promoting treatments. Multiple advancements have been made in the treatment of MPS with both hematopoietic cell transplantation (HCT) and enzyme replacement therapy (ERT). The long term benefit of these treatments on growth is unknown. This article will review the published data on growth in children with MPS, and describe preliminary data on the use of human growth hormone (hGH) in children with MPS. PMID:20563263

  3. Key variables influencing patterns of lava dome growth and collapse

    NASA Astrophysics Data System (ADS)

    Husain, T.; Elsworth, D.; Voight, B.; Mattioli, G. S.; Jansma, P. E.

    2013-12-01

    Lava domes are conical structures that grow by the infusion of viscous silicic or intermediate composition magma from a central volcanic conduit. Dome growth can be characterized by repeated cycles of growth punctuated by collapse, as the structure becomes oversized for its composite strength. Within these cycles, deformation ranges from slow long term deformation to sudden deep-seated collapses. Collapses may range from small raveling failures to voluminous and fast-moving pyroclastic flows with rapid and long-downslope-reach from the edifice. Infusion rate and magma rheology together with crystallization temperature and volatile content govern the spatial distribution of strength in the structure. Solidification, driven by degassing-induced crystallization of magma leads to the formation of a continuously evolving frictional talus as a hard outer shell. This shell encapsulates the cohesion-dominated soft ductile core. Here we explore the mechanics of lava dome growth and failure using a two-dimensional particle-dynamics model. This meshless model follows the natural evolution of a brittle carapace formed by loss of volatiles and rheological stiffening and avoids difficulties of hour-glassing and mesh-entangelment typical in meshed models. We test the fidelity of the model against existing experimental and observational models of lava dome growth. The particle-dynamics model follows the natural development of dome growth and collapse which is infeasible using simple analytical models. The model provides insight into the triggers that lead to the transition in collapse mechasnism from shallow flank collapse to deep seated sector collapse. Increase in material stiffness due to decrease in infusion rate results in the transition of growth pattern from endogenous to exogenous. The material stiffness and strength are strongly controlled by the magma infusion rate. Increase in infusion rate decreases the time available for degassing induced crystallization leading to a

  4. Colony patterning and collective hyphal growth of filamentous fungi

    NASA Astrophysics Data System (ADS)

    Matsuura, Shu

    2002-11-01

    Colony morphology of wild and mutant strains of Aspergillus nidulans at various nutrient and agar levels was investigated. Two types of colony patterning were found for these strains. One type produced uniform colonies at all nutrient and agar levels tested, and the other exhibited morphological change into disordered ramified colonies at low nutrient levels. Both types showed highly condensed compact colonies at high nutrient levels on low agar media that was highly diffusive. Disordered colonies were found to develop with low hyphal extension rates at low nutrient levels. To understand basic pattern selection rules, a colony model with three parameters, i.e., the initial nutrient level and the step length of nutrient random walk as the external parameters, and the frequency of nutrient uptake as an internal parameter, was constructed. At low nutrient levels, with decreasing nutrient uptake frequency under diffusive conditions, the model colony exhibited onsets of disordered ramification. Further, in the growth process of A. nidulans, reduction of hyphal extension rate due to a population effect of hyphae was found when hyphae form three-dimensional dense colonies, as compared to the case in which hyphal growth was restricted into two-dimensional space. A hyphal population effect was introduced in the colony model. Thickening of colony periphery due to the population effect became distinctive as the nutrient diffusion effect was raised at high nutrient levels with low hyphal growth rate. It was considered that colony patterning and onset of disorder were strongly governed by the combination of nutrient diffusion and hyphal growth rate.

  5. Cortical Folding Pattern and its Consistency Induced by Biological Growth

    PubMed Central

    Jalil Razavi, Mir; Zhang, Tuo; Liu, Tianming; Wang, Xianqiao

    2015-01-01

    Cortical folding, characterized by convex gyri and concave sulci, has an intrinsic relationship to the brain’s functional organization. Understanding the mechanism of the brain’s convoluted patterns can provide useful clues into normal and pathological brain function. In this paper, the cortical folding phenomenon is interpreted both analytically and computationally, and, in some cases, the findings are validated with experimental observations. The living human brain is modeled as a soft structure with a growing outer cortex and inner core to investigate its developmental mechanism. Analytical interpretations of differential growth of the brain model provide preliminary insight into critical growth ratios for instability and crease formation of the developing brain. Since the analytical approach cannot predict the evolution of cortical complex convolution after instability, non-linear finite element models are employed to study the crease formation and secondary morphological folds of the developing brain. Results demonstrate that the growth ratio of the cortex to core of the brain, the initial thickness, and material properties of both cortex and core have great impacts on the morphological patterns of the developing brain. Lastly, we discuss why cortical folding is highly correlated and consistent by presenting an intriguing gyri-sulci formation comparison. PMID:26404042

  6. Cortical Folding Pattern and its Consistency Induced by Biological Growth

    NASA Astrophysics Data System (ADS)

    Jalil Razavi, Mir; Zhang, Tuo; Liu, Tianming; Wang, Xianqiao

    2015-09-01

    Cortical folding, characterized by convex gyri and concave sulci, has an intrinsic relationship to the brain’s functional organization. Understanding the mechanism of the brain’s convoluted patterns can provide useful clues into normal and pathological brain function. In this paper, the cortical folding phenomenon is interpreted both analytically and computationally, and, in some cases, the findings are validated with experimental observations. The living human brain is modeled as a soft structure with a growing outer cortex and inner core to investigate its developmental mechanism. Analytical interpretations of differential growth of the brain model provide preliminary insight into critical growth ratios for instability and crease formation of the developing brain. Since the analytical approach cannot predict the evolution of cortical complex convolution after instability, non-linear finite element models are employed to study the crease formation and secondary morphological folds of the developing brain. Results demonstrate that the growth ratio of the cortex to core of the brain, the initial thickness, and material properties of both cortex and core have great impacts on the morphological patterns of the developing brain. Lastly, we discuss why cortical folding is highly correlated and consistent by presenting an intriguing gyri-sulci formation comparison.

  7. Study of the loss of pattern definition in diamond growth

    NASA Astrophysics Data System (ADS)

    Chen, Chia-Fu; Chen, Sheng-Hsiung

    1994-12-01

    Selectivity loss (i.e. deposition on a mirror-smooth finished silicon surface) during diamond film growth using a selective deposition technique was investigated. CH4-CO2 gas mixtures without supplying hydrogen were used to enhance the nucleation density. After pattern generation and ultrasonic agitation pretreatment, the Si substrates were dipped into a solution of HF:HNO3:H2O (1:1.1:10) for various lengths of time to increase the pattern definition during the second period of diamond film growth. It was found that the selectivity loss in the diamond films could be significantly reduced by increasing the dipping time. The nuclei formed in the nucleation step were etched using the above solution, which reduced the selectivity loss. Scanning electron microscopy and electron spectroscopy for chemical analysis were used to examine the selectivity loss and morphological change of the as-grown diamond films. It was also found that a higher CH4 concentration resulted in a high selective loss of diamond growth.

  8. Phasic temperature change patterns affect growth and tuberization in potatoes

    SciTech Connect

    Cao, W.; Tibbitts, T.W. . Dept. of Horticulture)

    1994-07-01

    This study determined the response of potato (Solanum tuberosum L., cv. Norland) plants to various patterns of air temperature changes over different growth periods. In each of two experiments under controlled environments, eight treatments of temperature changes were carried out in two growth rooms maintained at 17 and 22 C and a constant vapor pressure deficit of 0.60 kPa and 14-hour photoperiod. Plants were grown for 63 days after transplanting of tissue culture plantlets in 20-liter pots containing peat-vermiculite mix. Temperature changes were imposed on days 21 and 42, which were essentially at the beginning of tuber initiation and tuber enlargement, respectively, for this cultivar. Plants were moved between two temperature rooms to obtain eight temperature change patterns: 17-17-17, 17-17-22, 17-22-17, 22-17-17, 17-22-22, 22-17-22, 22-22-17, and 22-22-22C over three 21-day growth periods. At harvest on day 63, total plant dry weight was higher for the treatments beginning with 22 C than for those beginning with 17C, with highest biomass obtained at 22-22-17 and 22-17-17C. Shoot dry weight increased with temperature increased from 17-17-17 to 22-22-22C during the three growth periods. Tuber dry weight was highest with 22-17-17C, and lowest with 17-17-22 and 17-22-22C. With 22-17-17C, both dry weights of stolons and roots were lowest. Total tuber number and number of small tubers were highest with 17-17-17 and 17-17-22C, and lowest with 17-22-22 and 22-22-22C, whereas number of medium tubers was highest with 22-17-22C, and number of large tubers was highest with 22-17-17C. This study indicates that tuber development of potatoes is optimized with a phasic pattern of high temperature during early growth and low temperature during later growth.

  9. Materia Socio Medica is Indexed in Pubmed and Archived in PubMed Central.

    PubMed

    Masic, Izet

    2013-01-01

    Materia Socio Medica Journal has been accepted for archiving in PubMed Central from 2011. The journal started in 1993 as offi cial journal of Social Medicine Association of B&H. During last 3 years Mat Soc Med has included in almost all femous on-line databases (except WoS). All issues of Mat Soc Med published in 2012 are now visible on PubMed/PubMed Central.

  10. Patterns, Processes of Growth, and the Projection of Library Size: A Critical Review of the Literature on Academic Library Growth.

    ERIC Educational Resources Information Center

    Molyneux, Robert E.

    1986-01-01

    Reviews studies done on academic library growth in attempt to clarify three reasons for failure of these analyses to result in usable projections of library size. Highlights include patterns in library growth (hypothetical exponential and arithmetic growth), Fremont Rider's studies of growth, and literature on growth after Rider. (28 references)…

  11. Growth patterns of Chinese patients with Prader-Willi syndrome.

    PubMed

    Yang, Hongbo; Zhang, Mengqi; Song, Hongmei; Zhu, Huijuan; Pan, Hui

    2015-11-01

    The aim of the present study was to investigate the spontaneous development of growth and weight gain of patients with Prader-Willi syndrome (PWS) in Mainland China. We retrospectively analyzed 120 cases of PWS diagnosed from 1994 to 2014 in Mainland China. Scatter diagram of the growth data was compared to standardized growth curve. The length at birth was similar to the normal population and the mean birthweight is under the 50th centile of normal population. Heights in 43% (27/62) of patients had dropped off below the 3(rd) centile of their peers after 5 years of age. Weights in 65.9% (58/88) of patients had exceeded the 97(th) centile of their peers after 3 years of age. Early obesity is obvious in 92.9% (66/71) of patients with body mass index (BMI) up the 97(th) centile of their peers from 2-3 years of age. Final mean height is 149.3 ± 11.2 cm for females (n = 7) and 146.2 ± 9.8 cm for males (n = 6), showing 11.3 cm and 26.6 cm below the average height for normal Chinese girls and boys. The growth pattern of PWS in Mainland China is comparable to those in Caucasians. Early intervention with recombinant human growth hormone is warranted considering the early onset of growth retardation and obesity.

  12. Modelling spatial patterns of urban growth in Africa

    PubMed Central

    Linard, Catherine; Tatem, Andrew J.; Gilbert, Marius

    2013-01-01

    The population of Africa is predicted to double over the next 40 years, driving exceptionally high urban expansion rates that will induce significant socio-economic, environmental and health changes. In order to prepare for these changes, it is important to better understand urban growth dynamics in Africa and better predict the spatial pattern of rural-urban conversions. Previous work on urban expansion has been carried out at the city level or at the global level with a relatively coarse 5–10 km resolution. The main objective of the present paper was to develop a modelling approach at an intermediate scale in order to identify factors that influence spatial patterns of urban expansion in Africa. Boosted Regression Tree models were developed to predict the spatial pattern of rural-urban conversions in every large African city. Urban change data between circa 1990 and circa 2000 available for 20 large cities across Africa were used as training data. Results showed that the urban land in a 1 km neighbourhood and the accessibility to the city centre were the most influential variables. Results obtained were generally more accurate than results obtained using a distance-based urban expansion model and showed that the spatial pattern of small, compact and fast growing cities were easier to simulate than cities with lower population densities and a lower growth rate. The simulation method developed here will allow the production of spatially detailed urban expansion forecasts for 2020 and 2025 for Africa, data that are increasingly required by global change modellers. PMID:25152552

  13. Growth patterns of two marine isolates: adaptations to substrate patchiness?

    PubMed

    Pernthaler, A; Pernthaler, J; Eilers, H; Amann, R

    2001-09-01

    During bottle incubations of heterotrophic marine picoplankton, some bacterial groups are conspicuously favored. In an earlier investigation bacteria of the genus Pseudoalteromonas rapidly multiplied in substrate-amended North Sea water, whereas the densities of Oceanospirillum changed little (H. Eilers, J. Pernthaler, and R. Amann, Appl. Environ. Microbiol. 66:4634-4640, 2000). We therefore studied the growth patterns of two isolates affiliating with Pseudoalteromonas and Oceanospirillum in batch culture. Upon substrate resupply, Oceanospirillum lagged threefold longer than Pseudoalteromonas but reached more than fivefold-higher final cell density and biomass. A second, mobile morphotype was present in the starved Oceanospirillum populations with distinctly greater cell size, DNA and protein content, and 16S rRNA concentration. Contrasting cellular ribosome concentrations during stationary phase suggested basic differences in the growth responses of the two strains to a patchy environment. Therefore, we exposed the strains to different modes of substrate addition. During cocultivation on a single batch of substrates, the final cell densities of Oceanospirillum were reduced three times as much as those Pseudoalteromonas, compared to growth yields in pure cultures. In contrast, the gradual addition of substrates to stationary-phase cocultures was clearly disadvantageous for the Pseudoalteromonas population. Different growth responses to substrate gradients could thus be another facet affecting the competition between marine bacteria and may help to explain community shifts observed during enrichments.

  14. Patterns of growth and development in narcotic-exposed children.

    PubMed

    Lifschltz, M H; Wilson, G S

    1991-01-01

    The results of the studies reviewed indicate that intrauterine growth is adversely affected by drug use during pregnancy. Whether the impairment is a direct effect of narcotic exposure or is the result of the interaction of deleterious health, environmental, and socioeconomic factors closely associated with the lifestyle of the woman who abuses drugs cannot be determined at present. Reports on the long-term effects of drug use on growth and intellectual functioning in the offspring of women who abuse drugs are not consistent. While some studies indicate that most of the exposed infants exhibit catchup growth by 6 months of age (Lifschitz et al. 1983, 1985), one methodologically strong study suggests that methadone may have a small direct teratogenic effect reflected in reduced head size at 2 years of age (Hans 1989). Unexplained is the pattern of growth deceleration observed in some narcotic-exposed children (Lifschitz et al. 1983, 1985). The few available reports on long-term outcome concur that narcotic-exposed children have a high incidence of behavioral and learning problems (Strauss et al. 1979; Rosen and Johnson 1985; Wilson 1989), but population studies have been too small to demonstrate that they differ significantly from controls. There is a suggestion that narcotic use during pregnancy promotes a biological vulnerability to adverse environments, manifested in the neurobehavioral and intellectual areas.

  15. [Bibliometric analysis of current glaucoma research based on Pubmed database].

    PubMed

    Huang, Wen-bin; Wang, Wei; Zhou, Min-wen; Chen, Shi-da; Zhang, Xiu-lan

    2013-11-01

    To survey the distribution pattern and subject domain knowledge of worldwide glaucoma research based on literatures in Pubmed database. Literatures on glaucoma published in 2007 to 2011 were identified in Pubmed database. The analytic items of an article include published year, country, language author, and journal. After core mesh terms had been characterized by BICOMS, the co-occurrence matrix was built. Cluster analysis was finished by SPSS 20.0. Then visualized network was drawn using ucinet 6.0. Totally 6427 literatures were included, the number of annual articles changed slightly between 2007 and 2011. The United States, England, Germany, Australia, and France together accounted for 77.63% of articles. There were 52 high-frequency subjects and hot topics were clustered into the following 10 categories: (1) Pathology of optic disc and nerve fibers and OCT application, (2) METHODS: of visual field (VF) and visual function examination, (3) Glaucoma drug medications, (4) Pathology and physiology of primary open angle glaucoma (POAG) including VF and intraocular pressure (IOP), (5) Glaucoma surgery, (6) Gene research related to POAG, (7) Glaucoma disease pathology and animal models, (8) Ocular hypertension (OHT) induced complications and corneal changes, (9) Etiology of congenital glaucoma and complications, (10) Etiology and epidemiology of glaucoma. The visualized domain knowledge mapping was successfully built. The pathology of optic disc and nerve fibers, medications, and surgery were well developed. Study on IOP and visual field was in the core domain, which have an important link to etiology, diagnosis, and therapy. The researches on glaucomatous gene, disease pathology model, congenital glaucoma, etiology and epidemiology were not developed well, which are of great promotion space. The distribution pattern and subject domain knowledge of worldwide glaucoma research in the recent five years were shown by using bibliometric analysis.Western developed

  16. Remodeling patterns of occipital growth: a preliminary report.

    PubMed

    Kranioti, Elena F; Rosas, Antonio; García-Vargas, Samuel; Estalrrich, Almudena; Bastir, Markus; Peña-Melián, Angel

    2009-11-01

    Occipital growth depends on coordinated deposition and resorption on the external and internal surface and includes interrelated processes of movement: cortical drift, displacement, and relocation. The current work aspires to map patterns of remodeling activity on the endocranial surface of the occipital bone from childhood to adulthood using a larger study sample compared with previous studies. The study sample consists of 5 adult and 10 immature (2(1/4) to 8 years old) occipital bones from skeletal remains from the eighteenth and nineteenth century. Preparation of the samples includes the elaboration of negative impressions, positive replicas coated with gold, and observed with the reflected light microscope. Cerebellar fossae are typically resorptive in both immature and adult specimens. Cerebral fossae, on the other hand, exhibit a resorptive surface in early childhood and turn into depository around the age of 7 years, which places this transition within the age interval of the completion of cerebral development. Depository fields are also observed in adult cerebral fossae. The remodeling map presented here is consistent with the results of Mowbray (Anat Rec B New Anat 2005;283B:14-22) and differs from cellular patterns described by Enlow. Future research implicating more elements of the neurocapsule can shed light on the factors affecting and driving occipital growth.

  17. Pattern formation and growth kinetics in eutectic systems

    NASA Astrophysics Data System (ADS)

    Teng, Jing

    Growth patterns during liquid/solid phase transformation are governed by simultaneous effects of heat and mass transfer mechanisms, creation of new interfaces, jump of the crystallization units from liquid to solid and their rearrangement in the solid matrix. To examine how the above processes influence the scale of microstructure, two eutectic systems are chosen for the study: a polymeric system polyethylene glycol-p-dibromobenzene (PEG-DBBZ) and a simple molecular system succinonitrile (SCN)-camphor. The scaling law for SCN-camphor system is found to follow the classical Jackson-Hunt model of circular rod eutectic, where the diffusion in the liquid and the interface energy are the main physics governing the two-phase pattern. In contrast, a significantly different scaling law is observed for the polymer system. The interface kinetics of PEG phase and its solute concentration dependence thus have been critically investigated for the first time by directional solidification technique. A model is then proposed that shows that the two-phase pattern in polymers is governed by the interface diffusion and the interface kinetics. In SCN-camphor system, a new branch of eutectic, elliptical shape rod, is found in thin samples where only one layer of camphor rods is present. It is found that the orientation of the ellipse can change from the major axis in the direction of the thickness to the direction of the width as the velocity and/or the sample thickness is decreased. A theoretical model is developed that predicts the spacing and orientation of the elliptical rods in a thin sample. The single phase growth patterns of SCN-camphor system were also examined with emphasis on the three-dimensional single cell and cell/dendrite transition. For the 3D single cell in a capillary tube, the entire cell shape ahead of the eutectic front can be described by the Saffmann-Taylor finger only at extremely low growth rate. A 3D directional solidification model is developed to

  18. Pattern Formation and Growth Kinetics in Eutectic Systems

    SciTech Connect

    Teng, Jing

    2007-01-01

    Growth patterns during liquid/solid phase transformation are governed by simultaneous effects of heat and mass transfer mechanisms, creation of new interfaces, jump of the crystallization units from liquid to solid and their rearrangement in the solid matrix. To examine how the above processes influence the scale of microstructure, two eutectic systems are chosen for the study: a polymeric system polyethylene glycol-p-dibromobenzene (PEG-DBBZ) and a simple molecular system succinonitrile (SCN)-camphor. The scaling law for SCN-camphor system is found to follow the classical Jackson-Hunt model of circular rod eutectic, where the diffusion in the liquid and the interface energy are the main physics governing the two-phase pattern. In contrast, a significantly different scaling law is observed for the polymer system. The interface kinetics of PEG phase and its solute concentration dependence thus have been critically investigated for the first time by directional solidification technique. A model is then proposed that shows that the two-phase pattern in polymers is governed by the interface diffusion and the interface kinetics. In SCN-camphor system, a new branch of eutectic, elliptical shape rodl, is found in thin samples where only one layer of camphor rods is present. It is found that the orientation of the ellipse can change from the major axis in the direction of the thickness to the direction of the width as the velocity and/or the sample thickness is decreased. A theoretical model is developed that predicts the spacing and orientation of the elliptical rods in a thin sample. The single phase growth patterns of SCN-camphor system were also examined with emphasis on the three-dimensional single cell and cell/dendrite transition. For the 3D single cell in a capillary tube, the entire cell shape ahead of the eutectic front can be described by the Saffmann-Taylor finger only at extremely low growth rate. A 3D directional solidification model is developed to

  19. Analysis of PubMed User Sessions Using a Full-Day PubMed Query Log: A Comparison of Experienced and Nonexperienced PubMed Users

    PubMed Central

    2015-01-01

    Background PubMed is the largest biomedical bibliographic information source on the Internet. PubMed has been considered one of the most important and reliable sources of up-to-date health care evidence. Previous studies examined the effects of domain expertise/knowledge on search performance using PubMed. However, very little is known about PubMed users’ knowledge of information retrieval (IR) functions and their usage in query formulation. Objective The purpose of this study was to shed light on how experienced/nonexperienced PubMed users perform their search queries by analyzing a full-day query log. Our hypotheses were that (1) experienced PubMed users who use system functions quickly retrieve relevant documents and (2) nonexperienced PubMed users who do not use them have longer search sessions than experienced users. Methods To test these hypotheses, we analyzed PubMed query log data containing nearly 3 million queries. User sessions were divided into two categories: experienced and nonexperienced. We compared experienced and nonexperienced users per number of sessions, and experienced and nonexperienced user sessions per session length, with a focus on how fast they completed their sessions. Results To test our hypotheses, we measured how successful information retrieval was (at retrieving relevant documents), represented as the decrease rates of experienced and nonexperienced users from a session length of 1 to 2, 3, 4, and 5. The decrease rate (from a session length of 1 to 2) of the experienced users was significantly larger than that of the nonexperienced groups. Conclusions Experienced PubMed users retrieve relevant documents more quickly than nonexperienced PubMed users in terms of session length. PMID:26139516

  20. Characterizing growth patterns in longitudinal MRI using image contrast

    NASA Astrophysics Data System (ADS)

    Vardhan, Avantika; Prastawa, Marcel; Vachet, Clement; Piven, Joseph; Gerig, Guido

    2014-03-01

    Understanding the growth patterns of the early brain is crucial to the study of neuro-development. In the early stages of brain growth, a rapid sequence of biophysical and chemical processes take place. A crucial component of these processes, known as myelination, consists of the formation of a myelin sheath around a nerve fiber, enabling the effective transmission of neural impulses. As the brain undergoes myelination, there is a subsequent change in the contrast between gray matter and white matter as observed in MR scans. In this work, gray-white matter contrast is proposed as an effective measure of appearance which is relatively invariant to location, scanner type, and scanning conditions. To validate this, contrast is computed over various cortical regions for an adult human phantom. MR (Magnetic Resonance) images of the phantom were repeatedly generated using different scanners, and at different locations. Contrast displays less variability over changing conditions of scan compared to intensity-based measures, demonstrating that it is less dependent than intensity on external factors. Additionally, contrast is used to analyze longitudinal MR scans of the early brain, belonging to healthy controls and Down's Syndrome (DS) patients. Kernel regression is used to model subject-specific trajectories of contrast changing with time. Trajectories of contrast changing with time, as well as time-based biomarkers extracted from contrast modeling, show large differences between groups. The preliminary applications of contrast based analysis indicate its future potential to reveal new information not covered by conventional volumetric or deformation-based analysis, particularly for distinguishing between normal and abnormal growth patterns.

  1. Growth patterns for acervuli in human pineal gland

    PubMed Central

    Kim, Jinkyung; Kim, Hyun-Wook; Chang, Soeun; Kim, Jee Woong; Je, Jung Ho; Rhyu, Im Joo

    2012-01-01

    Acervuli are calcified concretions in the pineal gland (PG). Particularly interesting are their incidence and size, which are believed to affect neurological disorders and many physiological functions of PG such as regulating circadian rhythm. Despite long investigations for a century, detailed growth mechanism of acervuli has yet to be studied. Here we study the growth morphology of acervuli in human PGs by a direct visualization in 3-dimension (3-D) using a synchrotron X-ray imaging method. For an entire PG, non-aggregated acervuli show Gaussian distribution in size with 47±28 µm. The 3-D volume rendered images of acervuli reveal that the bumpy surfaces developed by lamination result in the mulberry-like structure. In addition, coalescence of multiple acervuli leads to large-scale lamination on the whole aggregate. We suggest a novel hypothesis on the growth patterns of acervuli by their nucleation density (Nd): i) mulberry-like structure at low Nd, and ii) large-scale lamination on an aggregate at high Nd. PMID:23248747

  2. The growth patterns of three hindlimb muscles in the chicken.

    PubMed Central

    Helmi, C; Cracraft, J

    1977-01-01

    This study was designed to investigate the growth patterns of three hindlimb muscles of the chicken relative to the functional-biomechanical demands of increasing body size. The biceps femoris, a bipennate non-postural muscle, grew relatively faster in terms of wet and dry weight than did the parallel-fibred adductor superficialis or the unipennate adductor profundus, both postural muscles. All three muscles exhibited positive allometry (relative to body weight) in muscle length but only biceps femoris and adductor profundus showed positive allometry in cross sectional area adductor superficialis having isometric growth in this parameter. In biceps femoris and adductor superficialis the lengths of the longest and shortest fasciculi grew at equal rates, whereas in adductor profundus the shortest fasciculi grew faster than the longest. We conclude that muscle weight alone is an insufficient indicator of changing function in growing muscle. Hence, growth studies should include other functionally relevant parameters such as cross sectional area, which is proportional to the force-producing capabilities of the muscle, or fibre (fasciculus) length, which is indicative of the absolute amount of stretching or shortening that is possible and of the contraction velocity. PMID:885779

  3. Patterned growth of tungsten diselenide flakes by chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Wang, Zhendong; Huang, Qi; Chen, Peng; Wang, Jianyu; Lu, Yan; Zhang, Sihong; Liang, Xuelei; Wang, Li

    2017-08-01

    By introducing prepatterned Pt/Ti dots, arrays of WSe2 flakes have been successfully grown on SiO2 substrates by chemical vapor deposition, opening a new pathway for the large-scale production of WSe2-based devices. The WSe2 flakes are high-quality single crystals characterized by transmission electron microscopy and Raman spectroscopy. Field-effect transistors were fabricated on these WSe2 flakes, and the field effect mobility was measured to be 11.0 cm2 V-1 s-1 and an on/off ratio of ˜106 was achieved. The growth of highly patterned WSe2 flake arrays facilitates the fabrication of WSe2 flake-based integrated devices.

  4. Effects of hypodontia on craniofacial structures and mandibular growth pattern.

    PubMed

    Kreczi, Amelia; Proff, Peter; Reicheneder, Claudia; Faltermeier, Andreas

    2011-12-06

    This study was performed to examine craniofacial structures in persons with hypodontia and to reveal any differences, that may occur, when agenetic teeth are only found in the maxilla, the mandible or in both jaws. The groups consistent of 50 children (33 girls, 17 boys) aged between 9 and 13.5 years were analyzed and assigned to three subgroups. Group 1 = upper jaw hypodontia. Group 2 = lower jaw hypodontia. Group 3 = hypodontia in both jaws. Eleven angular and three index measurements from lateral encephalographs and two linear measurements from dental blaster casts were calculated. All data was statistically analyzed, parameters with p < 5% were investigated for each subgroup respectively. In comparison with standards the study group showed bimaxillary retrognathism and a reduction of the lower anterior facial height. Moreover both overbite and overjet significantly increased. Other values laid within the normal ranges. Evaluating results of the subgroups, differences in the means of SNA, SNB and overjet between the groups were observed.Analysis of the mandibular growth pattern revealed, that neither vertical nor horizontal patterns are dominant in hypodontia patients. In certain dentofacial parameters differences between persons with hypodontia and such with full dentition exist. According to our findings agenetic teeth may have a negative influence on the saggital development of a jaw and the lower face and may be responsible for increased overbites. This should receive attention in orthodontic treatment of hypodontia patients. © 2011 Kreczi et al; licensee BioMed Central Ltd.

  5. Compact or fractal patterns in diffusion limited growth

    NASA Astrophysics Data System (ADS)

    Ben Amar, Martine

    1993-02-01

    Fractal viscous fingering patterns are observed in an infinite Hele-Shaw cell at long times when the capillary forces become negligible. On the contrary, growth of monocrystals from a punctual seed shows dendrites growing independently in 4 or 6 directions, according to the crystal symmetry. A close comparison of numerical and experimental data explains first the origin of the tip-splitting instability in radial growth and shows that it can be inhibited by the anisotropy of surface tension. Des structures fractales ont été observées en digitations visqueuses en cellule de Hele-Shaw et aux temps longs lorsque les forces capillaires deviennent négligeables. Par opposition, la croissance de monocristaux à partir d'un germe ponctuel fait apparaître des dendrites croissant dans 4 ou 6 directions selon la symétrie cristalline. Une comparaison entre des résultats numériques et des données expérimentales explique l'origine de l'instabilité de dédoublement des pointes en croissance radiale et montre qu'elle peut être supprimée par l'anisotropie cristalline.

  6. Rhone deep-sea fan: morphostructure and growth pattern

    SciTech Connect

    Droz, L.; Bellaiche, G.

    1985-03-01

    A detailed bathymetric survey of the Rhone deep-sea fan and its feeder canyon using Sea-Beam, reveals morphologic features such as very tight meanders of the canyon and channel courses, cutoff meanders, and downslope narrowing of the inner channel floor. Striking similarities exist between these deep-sea features and some continental landforms, especially in alluvial plain areas or desert environments. Sea-Beam also reveals evidence of huge slump scars affecting the slope and fan. The superficial structure of the Rhone Fan results from the stacking of numerous lenticular acoustic units displaying specific seismic characters in which the authors recognized channel and levee facies. Except in the upper fan area, these units have not been constant; they have generally migrated, owing to shifting of the channel throughout fan evolution. Construction of the fan probably began as early as the early Pliocene and continued to the close of the Wurmian (late Wisconsinian). The fan's growth pattern could be associated with climatic fluctuations. The principal sedimentary mechanism responsible for the growth of the fan appears to be turbidity currents, but mass gravity flows have also been an important factor in building the fan by occasionally blocking the main channel and forcing it to migrate.

  7. Estimation of body size and growth patterns in Korean boys.

    PubMed

    Lee, Youngsuk

    2015-04-24

    Anthropometric surveys devised by each country attempt to fulfill the requirements of the manufacturers, designers, and human welfare device production, providing them with data and tools and allowing them to face both the internal and export markets. To this end, national anthropometric data collections and comparisons including three-dimensional information, together with comparison of these data among countries, are conducted at both the domestic and global levels. The anthropometric data of the Korean population measured in 2013 (Korean Agency for Technology and Standard (KATS) 2013 data) and the data collected from 2010 (KATS 2010 data) that was conducted on 710 males between the ages of 13 and 18 years were analyzed in this section to obtain information on Korean boys' physical features and growth. The mean height increased about 5 cm from 13 to 14 years which shows the early fast maturing somatotype. Also, the mean height of boys aged from 15 to 16 increased about 1 to 2 cm. For the results of body proportion rate index against height, they show 0.93, 0.81, 0.38, 0.99, and 0.26 times the height in eye height, shoulder height, fingertip height, and span and maximum shoulder breadth, respectively, in 16-year-old boys. For the body mass index, the weight is increased from the age of 16 years. There are several studies that cover growth features of the entire range from birth to maturity, and they have reported the comparison of the growth patterns among Europeans. Even though such researches have been made, as for the industry, the human modeling tools based on the anthropometric data and morphological features that cover all the countries should be developed for well-fit garments and other human-oriented design process.

  8. Effects of size at birth, childhood growth patterns and growth hormone treatment on leukocyte telomere length

    PubMed Central

    Smeets, Carolina C. J.; Codd, Veryan; Denniff, Matthew; Samani, Nilesh J.; Hokken-Koelega, Anita C. S.

    2017-01-01

    Background Small size at birth and rapid growth in early life are associated with increased risk of cardiovascular disease in later life. Short children born small for gestational age (SGA) are treated with growth hormone (GH), inducing catch-up in length. Leukocyte telomere length (LTL) is a marker of biological age and shorter LTL is associated with increased risk of cardiovascular disease. Objectives To investigate whether LTL is influenced by birth size, childhood growth and long-term GH treatment. Methods We analyzed LTL in 545 young adults with differences in birth size and childhood growth patterns. Previously GH-treated young adults born SGA (SGA-GH) were compared to untreated short SGA (SGA-S), SGA with spontaneous catch-up to a normal body size (SGA-CU), and appropriate for gestational age with a normal body size (AGA-NS). LTL was measured using a quantitative PCR assay. Results We found a positive association between birth length and LTL (p = 0.04), and a trend towards a positive association between birth weight and LTL (p = 0.08), after adjustments for gender, age, gestational age and adult body size. Weight gain during infancy and childhood and fat mass percentage were not associated with LTL. Female gender and gestational age were positively associated with LTL, and smoking negatively. After adjustments for gender, age and gestational age, SGA-GH had a similar LTL as SGA-S (p = 0.11), SGA-CU (p = 0.80), and AGA-NS (p = 0.30). Conclusions Larger size at birth is positively associated with LTL in young adulthood. Growth patterns during infancy and childhood are not associated with LTL. Previously GH-treated young adults born SGA have similar LTL as untreated short SGA, SGA with spontaneous catch-up and AGA born controls, indicating no adverse effects of GH-induced catch-up in height on LTL. PMID:28178350

  9. Bioconvective patterns, synchrony, and survival. [in light-limited growth model of motile algae culture

    NASA Technical Reports Server (NTRS)

    Noever, David A.

    1990-01-01

    With and without bioconvective pattern formation, a theoretical model predicts growth in light-limited cultures of motile algae. At the critical density for pattern formation, the resulting doubly exponential population curves show an inflection. Such growth corresponds quantitatively to experiments in mechanically unstirred cultures. This attaches survival value to synchronized pattern formation.

  10. Growth Patterns and E-Moderating Supports in Asynchronous Online Discussions in an Undergraduate Blended Course

    ERIC Educational Resources Information Center

    Ghadirian, Hajar; Ayub, Ahmad Fauzi Mohd; Bakar, Kamariah Binti Abu; Hassanzadeh, Maryam

    2016-01-01

    This study presents a case study of asynchronous online discussions' (AOD) growth patterns in an undergraduate blended course to address the gap in our current understanding of how threads are developed in peer-moderated AODs. Building on a taxonomy of thread pattern proposed by Chan, Hew and Cheung (2009), growth patterns of thirty-six forums…

  11. Bioconvective patterns, synchrony, and survival. [in light-limited growth model of motile algae culture

    NASA Technical Reports Server (NTRS)

    Noever, David A.

    1990-01-01

    With and without bioconvective pattern formation, a theoretical model predicts growth in light-limited cultures of motile algae. At the critical density for pattern formation, the resulting doubly exponential population curves show an inflection. Such growth corresponds quantitatively to experiments in mechanically unstirred cultures. This attaches survival value to synchronized pattern formation.

  12. Episodic patterns of growth hormone secretion and growth hormone status of normal and tibial dyschondroplastic chickens.

    PubMed

    Vasilatos-Younken, R; Leach, R M

    1986-01-01

    Growth hormone status of normal and tibial dyschondroplastic (TD) birds was determined in 25 d old male chicks genetically selected for high and low incidence of TD. Birds were surgically prepared with indwelling venous catheters and blood samples remotely removed at 20 min intervals for 6 h to establish secretory patterns. Birds were maintained under a 16L:8D cycle, with free access to feed and water at all times. In a second experiment, secretory capacity was evaluated by administering a 10 micrograms/kg body weight dose of thyrotrophin releasing hormone (TRH). Blood samples were removed at 0, 5, 10, 20, 30, 60 and 120 min post-infusion of either TRH or saline (control). All birds displayed pulsatile patterns of GH secretion, with an average peak duration of 60 min and a 90 min inter-peak interval. Dyschondroplastic birds exhibited 50% higher mean peak amplitudes than normal birds (P less than .06), however, this difference was not translated into overall mean or total (curve area) differences. The magnitude of response to a TRH challenge was greater (P less than .10) for TD than for normal birds. In view of the relationships observed in other species between secretory pattern characteristics such as peak amplitude, and growth characteristics, it is suggested that differences in GH status of dyschondroplastic relative to normal birds may be related to initiation of the TD lesion.

  13. Bosnian and Herzegovinian medical scientists in PubMed database.

    PubMed

    Masic, Izet

    2013-01-01

    In this paper it is shortly presented PubMed as one of the most important on-line databases of the scientific biomedical literature. Also, the author has analyzed the most cited authors, professors of the medical faculties in Bosnia and Herzegovina, from the published papers in the biomedical journals abstracted and indexed in PubMed.

  14. Patterns of growth associated with the timing of adiposity rebound.

    PubMed

    Williams, Sheila M; Goulding, Ailsa

    2009-02-01

    This study was undertaken to evaluate the effects of age of adiposity rebound (AR) on measures of fat mass between ages 7 and 11 years, maturity, and adiposity in 458 children from a birth cohort studied to age 26 years. Patterns of growth between ages 3 and 26 years and changes in fat mass index between 7 and 11 years in groups with early (<5.5 years for boys and <5 years for girls), average (between 5.5 and 7.5 years for boys and between 5 and 7 years for girls), and late AR (> or =7.5 years for boys and > or =7 years for girls) are described. The mean z-scores for BMI, height, and weight increased between age 3 years and adolescence in the early-rebound group and decreased in the late-rebound group. The differences were maintained until adulthood for BMI and weight. Disproportionately high increases in fat mass index during growth (7-11 years), more advanced bone age in boys at age 7 years, and earlier menarche in girls were evident in the early-rebound group. The relative risks at 26 years of being overweight (BMI 25-29.9 kg/m(2)) and obese (BMI > or =30 kg/m(2)) were 2.70 (95% confidence interval (CI): 1.55, 4.66) and 5.91 (95% CI: 3.03, 11.55) respectively, using the average group as the reference. The corresponding relative risks for adult waist girths exceeding international cut points were 2.12 (95% CI: 1.09, 4.13) and 3.32 (95% CI: 1.46, 7.54). Thus, early rebound is associated with increased depositions of fat in middle childhood, and risks associated with early rebound persist at least until early adulthood.

  15. Invited Article: Plasmonic growth of patterned metamaterials with fractal geometry

    NASA Astrophysics Data System (ADS)

    Takeyasu, Nobuyuki; Taguchi, Natsuo; Nishimura, Naoki; Cheng, Bo Han; Kawata, Satoshi

    2016-08-01

    Large-scale metallic three-dimensional (3D) structures composed of sub-wavelength fine details, called metamaterials, have attracted optical scientists and materials scientists because of their unconventional and extraordinary optical properties that are not seen in nature. However, existing nano-fabrication technologies including two-photon fabrication, e-beam, focused ion-beam, and probe microscopy are not necessarily suitable for fabricating such large-scale 3D metallic nanostructures. In this article, we propose a different method of fabricating metamaterials, which is based on a bottom-up approach. We mimicked the generation of wood forest under the sunlight and rain in nature. In our method, a silver nano-forest is grown from the silver seeds (nanoparticles) placed on the glass substrate in silver-ion solution. The metallic nano-forest is formed only in the area where ultraviolet light is illuminated. The local temperature increases at nano-seeds and tips of nano-trees and their branches due to the plasmonic heating as a result of UV light excitation of localized mode of surface plasmon polaritons. We have made experiments of growth of metallic nano-forest patterned by the light distribution. The experimental results show a beautiful nano-forest made of silver with self-similarity. Fractal dimension and spectral response of the grown structure are discussed. The structures exhibit a broad spectral response from ultraviolet to infrared, which was used for surface-enhanced Raman detection of molecules.

  16. Growth patterns for etiolated soybeans germinated under spaceflight conditions

    NASA Astrophysics Data System (ADS)

    Levine, Howard G.; Piastuch, William C.

    In the GENEX (GENe EXpression) spaceflight experiment (flown on STS-87), six surface sterilized soybean seeds ( Glycine max cv McCall) were inserted into each of 32 autoclaved plastic seed growth pouches containing an inner germination paper sleeve (for a total of 192 seeds). The pouches were stowed within a mid-deck locker until Mission Flight Day 10, at which time an astronaut added water to initiate the process of seed germination on-orbit and subsequently transferred them to four light-tight aluminum canisters called BRIC-60s (Biological Research In Canisters). We report here on the morphological characteristics of: (1) the recovered flight plants ( N = 177), (2) the corresponding ground control population ( N = 183), plus (3) additional controls grown on the ground under clinostat conditions ( N = 93). No significant morphological differences were found between the flight, ground control and clinorotated treatments for either the cotyledons or hypocotyls. There were, however, significantly longer primary roots produced in the flight population relative to the ground control population, which in turn had significantly longer primary roots than the clinorotated population. This same pattern was observed relative to the production of lateral roots (flight > control > clinorotated). Taken together with previous literature reports, we believe that there is now sufficient evidence to conclude that plants grown under conditions of microgravity will generally exhibit enhanced root production relative to their ground control counterparts. Some causes underlying this phenomenon are speculated on.

  17. Peptide microarray patterning for controlling and monitoring cell growth.

    PubMed

    Lin, Edith; Sikand, Adhirath; Wickware, Jessica; Hao, Yubin; Derda, Ratmir

    2016-04-01

    microarrays of peptide-terminated self-assembled monolayers (SAMs). To demonstrate the utility of these arrays in phenotypic assays with mammalian cells, we monitored the induction of epithelial to mesenchymal transition (EMT) in murine mammary epithelial cells using specific peptide ligands printed on these arrays. Novelty: We, and others, have published several strategies for producing peptide-based arrays suitable for long-term phenotypic assays. Many reports relied on patterning steps that made adaptation difficult. The use of a DNA microarray printer as the sole production tool simplified the production of peptide microarrays and increased the throughput of this technology. We confirmed that simplification in production did not compromise the performance of the array; it is still possible to study short-term adhesion, long-term growth, and complex phenotypic responses, such as EMT, in the cells. EMT was studied using immunofluorescent staining after four days of culture. This methodology will serve as a foundation for future screening of instructive biomaterials in our research group. As DNA printers are broadly available in academic institutions, we foresee rapid adaptation of this approach by academic researchers. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  18. [Effects of substrate-aeration cultivation pattern on tomato growth].

    PubMed

    Zhao, Xu; Li, Tian-Lai; Sun, Zhou-Ping

    2010-01-01

    Aeroponics can increase the fruit yield of tomato plant, but its cost is very high. In this paper, tomato seedlings were planted with three cultures, i. e., whole perlite culture (CK), perlite-aeration culture (T1), and aeroponics (T2), and a comparative study was made on the seedlings growth. Compared with CK, T1 improved the gas environment in root zone significantly, with the CO2 and O2 concentrations in root zone being 0.2 and 1.17 times higher, and increased the plant height and stem diameter after 60 days of transplanting by 5.1% and 8.4%, respectively. The plant net photosynthetic rate of T1 was significantly higher than that of CK, with the maximum value after transplanting 45 days increased by 13%. T1 also increased the root activity and ion absorbing ability significantly, with the root activity after transplanting 45 days being 1.23 times of CK, and the root K, Ca, and Mg contents after transplanting 60 days increased by 31%, 37%, and 27%, respectively. The fruit yield of T1 was 1.16 times of CK. No significant differences in these indices were observed between T1 and T2, and less difference in the fruit soluble sugar and organic acid contents as well as the sugar-acid ratio was found among CK, T1, and T2. It was suggested that perlite-aeration cultivation pattern was an easy and feasible way to markedly improve the fruit yield of tomato plant.

  19. Using PubMed effectively to access the orthopaedic literature.

    PubMed

    Clough, J F Myles; Hitchcock, Kristin; Nelson, David L

    2011-01-01

    PubMed is the free public Internet interface to the US National Library of Medicine's MEDLINE database of citations to medical scientific articles. Many orthopaedic surgeons use PubMed on a regular basis, but most orthopaedic surgeons have received little or no training in how to use PubMed effectively and express frustration with the experience. Typical problems encountered are data overload with very large numbers of returns to look through, failure to find a specific article, and a concern that a search has missed important papers. It is helpful to understand the system used to enter journal articles into the database and the classification of the common types of searches and to review suggestions for the best ways to use the PubMed interface and find sources for search teaching and assistance.

  20. PubMed searches: overview and strategies for clinicians.

    PubMed

    Lindsey, Wesley T; Olin, Bernie R

    2013-04-01

    PubMed is a biomedical and life sciences database maintained by a division of the National Library of Medicine known as the National Center for Biotechnology Information (NCBI). It is a large resource with more than 5600 journals indexed and greater than 22 million total citations. Searches conducted in PubMed provide references that are more specific for the intended topic compared with other popular search engines. Effective PubMed searches allow the clinician to remain current on the latest clinical trials, systematic reviews, and practice guidelines. PubMed continues to evolve by allowing users to create a customized experience through the My NCBI portal, new arrangements and options in search filters, and supporting scholarly projects through exportation of citations to reference managing software. Prepackaged search options available in the Clinical Queries feature also allow users to efficiently search for clinical literature. PubMed also provides information regarding the source journals themselves through the Journals in NCBI Databases link. This article provides an overview of the PubMed database's structure and features as well as strategies for conducting an effective search.

  1. Root Growth Patterns and Morphometric Change Based on the Growth Media

    NASA Astrophysics Data System (ADS)

    Schultz, Eric R.; Paul, Anna-Lisa; Ferl, Robert J.

    2016-12-01

    Arabidopsis thaliana roots skew with minimal waving in the microgravity environment of the International Space Station. Root skewing and root waving have been studied on the ground as well as in spaceflight, but often using different media types. In this study, Arabidopsis seedlings were grown on nutrient media plates that were comprised of various gelling agents with varied hardness in order to better assess these media for spaceflight research experiments. ImageJ was used to quantify the root morphology of 8-dayold seedlings, while R was used to perform statistical analyses. Root growth was drastically different between Difco agar, agarose, and Phytagel. Additionally, root waving masked skewing in certain media. Regression analysis revealed overall patterns when organized by hardness but also revealed that differences in media type had more of an impact on root growth than hardness itself. Different arrangements of media around the root tip revealed that roots grown on the media surface were longer and had fewer waves per millimeter than roots grown embedded in media. The implications for spaceflight research are discussed.

  2. Bone histology. Evolution of growth pattern in birds.

    PubMed

    Chinsamy, A; Elzanowski, A

    2001-07-26

    Living (neornithine) birds grow up rapidly and without interruption, terminating their growth within one year and, with a few secondary exceptions, starting to fly only after or near the completion of growth. Bone histology has revealed that pre-avian theropods also grew fast for most of the postnatal period, but that this growth was usually intermittent and probably extended for more than one year. We have found surprising evidence for an early postnatal slowing-down of growth in two lineages of flying basal birds, which suggests that birds may have started their evolution as precocious fliers.

  3. Local tissue growth patterns underlying normal fetal human brain gyrification quantified in utero

    PubMed Central

    Rajagopalan, Vidya; Scott, Julia; Habas, Piotr A.; Kim, Kio; Corbett-Detig, James; Rousseau, Francois; Barkovich, A. James; Glenn, Orit A.; Studholme, Colin

    2011-01-01

    Existing knowledge of growth patterns in the living fetal human brain is based upon in utero imaging studies by MRI and ultrasound, which describe overall growth and provided mainly qualitative findings. However, formation of the complex folded cortical structure of the adult brain requires, in part, differential rates of regional tissue growth. To better understand these local tissue growth patterns, we applied recent advances in fetal MRI motion correction and computational image analysis techniques to 40 normal fetal human brains covering a period of primary sulcal formation (20-28 gestational weeks). Growth patterns were mapped by quantifying tissue locations that were expanding more or less quickly than the overall cerebral growth rate, which reveal increasing structural complexity. We detected increased local relative growth rates in the formation of the pre- and post-central gyri, right superior temporal gyrus and opercula, which differentiated between the constant growth rate in underlying cerebral mantle and the accelerating rate in the cortical plate undergoing folding. Analysis focused on the cortical plate revealed greater volume increases in parietal and occipital regions compared to the frontal lobe. Cortical plate growth patterns constrained to narrower age ranges showed that gyrification, reflected by greater growth rates, was more pronounced after 24 gestational weeks. Local hemispheric volume asymmetry was located in the posterior peri-Sylvian area associated with structural lateralization in the mature brain. These maps of fetal brain growth patterns construct a spatially specific baseline of developmental biomarkers with which to correlate abnormal development in the human. PMID:21414909

  4. Comparison of PubMed and Google Scholar literature searches.

    PubMed

    Anders, Michael E; Evans, Dennis P

    2010-05-01

    Literature searches are essential to evidence-based respiratory care. To conduct literature searches, respiratory therapists rely on search engines to retrieve information, but there is a dearth of literature on the comparative efficiencies of search engines for researching clinical questions in respiratory care. To compare PubMed and Google Scholar search results for clinical topics in respiratory care to that of a benchmark. We performed literature searches with PubMed and Google Scholar, on 3 clinical topics. In PubMed we used the Clinical Queries search filter. In Google Scholar we used the search filters in the Advanced Scholar Search option. We used the reference list of a related Cochrane Collaboration evidence-based systematic review as the benchmark for each of the search results. We calculated recall (sensitivity) and precision (positive predictive value) with 2 x 2 contingency tables. We compared the results with the chi-square test of independence and Fisher's exact test. PubMed and Google Scholar had similar recall for both overall search results (71% vs 69%) and full-text results (43% vs 51%). PubMed had better precision than Google Scholar for both overall search results (13% vs 0.07%, P < .001) and full-text results (8% vs 0.05%, P < .001). Our results suggest that PubMed searches with the Clinical Queries filter are more precise than with the Advanced Scholar Search in Google Scholar for respiratory care topics. PubMed appears to be more practical to conduct efficient, valid searches for informing evidence-based patient-care protocols, for guiding the care of individual patients, and for educational purposes.

  5. Class II correction in a growing patient with hyperdivergent growth patterns and severe overjet.

    PubMed

    Park, Jae Hyun

    2010-01-01

    In general, the success of Class II treatment depends as much on the skill of the orthodontist as it does on a favorable facial-growth pattern. Lack of sufficient favorable growth during treatment will make it difficult to correct the skeletal malrelationship or significantly improve the facial profile. The case report presents the treatment of a patient with a Class II, Division 1 malocclusion with severe overjet and a hyperdivergent growth pattern. © 2011 BY QUINTESSENCE PUBLISHING CO, INC.

  6. Temporal consistency of spatial pattern in growth of the mussel, Mytilus edulis: Implications for predictive modelling

    NASA Astrophysics Data System (ADS)

    Bergström, Per; Lindegarth, Susanne; Lindegarth, Mats

    2013-10-01

    Human pressures on coastal seas are increasing and methods for sustainable management, including spatial planning and mitigative actions, are therefore needed. In coastal areas worldwide, the development of mussel farming as an economically and ecologically sustainable industry requires geographic information on the growth and potential production capacity. In practice this means that coherent maps of temporally stable spatial patterns of growth need to be available in the planning process and that maps need to be based on mechanistic or empirical models. Therefore, as a first step towards development of models of growth, we assessed empirically the fundamental requirement that there are temporally consistent spatial patterns of growth in the blue mussel, Mytilus edulis. Using a pilot study we designed and dimensioned a transplant experiment, where the spatial consistency in the growth of mussels was evaluated at two resolutions. We found strong temporal and scale-dependent spatial variability in growth but patterns suggested that spatial patterns were uncoupled between growth of shell and that of soft tissue. Spatial patterns of shell growth were complex and largely inconsistent among years. Importantly, however, the growth of soft tissue was qualitatively consistent among years at the scale of km. The results suggest that processes affecting the whole coastal area cause substantial differences in growth of soft tissue among years but that factors varying at the scale of km create strong and persistent spatial patterns of growth, with a potential doubling of productivity by identifying the most suitable locations. We conclude that the observed spatial consistency provides a basis for further development of predictive modelling and mapping of soft tissue growth in these coastal areas. Potential causes of observed patterns, consequences for mussel-farming as a tool for mitigating eutrophication, aspects of precision of modelling and sampling of mussel growth as well

  7. Infant feeding and growth trajectory patterns in childhood and body composition in young adulthood.

    PubMed

    Rzehak, Peter; Oddy, Wendy H; Mearin, M Luisa; Grote, Veit; Mori, Trevor A; Szajewska, Hania; Shamir, Raanan; Koletzko, Sibylle; Weber, Martina; Beilin, Lawrence J; Huang, Rae-Chi; Koletzko, Berthold

    2017-08-01

    Background: Growth patterns of breastfed and formula-fed infants may differ, with formula-fed infants growing more rapidly than breastfed infants into childhood and adulthood.Objective: Our objectives were to identify growth patterns and investigate early nutritional programming potential on growth patterns at 6 y and on body composition at 20 y.Design: The West Australian Pregnancy Cohort (Raine) Study and 3 European cohort studies (European Childhood Obesity Trial, Norwegian Human Milk Study, and Prevention of Coeliac Disease) that collaborate in the European Union-funded Early Nutrition project combined, harmonized, and pooled data on full breastfeeding, anthropometry, and body composition. Latent growth mixture modeling was applied to identify growth patterns among the 6708 individual growth trajectories. The association of full breastfeeding for <3 mo compared with ≥3 mo with the identified trajectory classes was assessed by logistic regression. Differences in body composition at 20 y among the identified trajectory classes were tested by analysis of variance.Results: Three body mass index (BMI; in kg/m(2)) trajectory patterns were identified and labeled as follows-class 1: persistent, accelerating, rapid growth (5%); class 2: early, nonpersistent, rapid growth (40%); and class 3: normative growth (55%). A shorter duration of full breastfeeding for <3 mo was associated with being in rapid-growth class 1 (OR: 2.66; 95% CI: 1.48, 4.79) and class 2 (OR: 1.96; 95% CI: 1.51, 2.55) rather than the normative-growth class 3 after adjustment for covariates. Both rapid-growth classes showed significant associations with body composition at 20 y (P < 0.0001).Conclusions: Full breastfeeding for <3 mo compared with ≥3 mo may be associated with rapid growth in early childhood and body composition in young adulthood. Rapid-growth patterns in early childhood could be a mediating link between infant feeding and long-term obesity risk. © 2017 American Society for Nutrition.

  8. Actinic keratoses show variable histological basal growth patterns - a proposed classification adjustment.

    PubMed

    Schmitz, L; Gambichler, T; Gupta, G; Stücker, M; Stockfleth, E; Szeimies, R M; Dirschka, T

    2017-08-10

    Common histological classification schemes of actinic keratoses (AK) do not evaluate growth patterns at basal epidermal aspects of AK. Until now, the importance of basal epidermal growth patterns of AK has not been studied. To investigate the extent of atypical keratinocytes throughout the epidermis and variation in basal growth patterns of AK. AK lesions occurring on the head/face from patients seen in routine practice were assessed histologically. We determined histological grade (AK I-III), basal growth patterns of atypical keratinocytes (crowding, budding, papillary sprouting) and accompanying parameters. Of the 246 lesions included, 28.0% were histologically classified as AK I, 46.7% as AK II, and 25.2% as AK III. 26.4% of the basal growth patterns were classified as crowding (pro I), 49.6% as budding (pro II), 17.9% as papillary sprouting (pro III) and 6.1% without basal directed growth. No significant correlation of the histological AK I-III grading and underlying growth patterns was observed (P= 0.4666). However, adnexal structure involvement (OR= 2.37; 95%CI 1.21-4.65), infiltration (OR= 2.53; 95%CI 1.31-4.90) and increased number of vessels (OR= 2.56; 95%CI 1.42-4.65) were independent positive predictive markers for pro II and pro III basal growth patterns. Basal growth patterns (pro I-III) in AK do not correlate with the established AK I-III histological grading system. Besides the degree of upward extension, varying degrees of downward extension exist. Histological classification should consider both, upwards and downward growth patterns when assessing AK. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  9. Computational method for quantifying growth patterns at the adaxial leaf surface in three dimensions.

    PubMed

    Remmler, Lauren; Rolland-Lagan, Anne-Gaëlle

    2012-05-01

    Growth patterns vary in space and time as an organ develops, leading to shape and size changes. Quantifying spatiotemporal variations in organ growth throughout development is therefore crucial to understand how organ shape is controlled. We present a novel method and computational tools to quantify spatial patterns of growth from three-dimensional data at the adaxial surface of leaves. Growth patterns are first calculated by semiautomatically tracking microscopic fluorescent particles applied to the leaf surface. Results from multiple leaf samples are then combined to generate mean maps of various growth descriptors, including relative growth, directionality, and anisotropy. The method was applied to the first rosette leaf of Arabidopsis (Arabidopsis thaliana) and revealed clear spatiotemporal patterns, which can be interpreted in terms of gradients in concentrations of growth-regulating substances. As surface growth is tracked in three dimensions, the method is applicable to young leaves as they first emerge and to nonflat leaves. The semiautomated software tools developed allow for a high throughput of data, and the algorithms for generating mean maps of growth open the way for standardized comparative analyses of growth patterns.

  10. Use of scientific social networking to improve the research strategies of PubMed readers.

    PubMed

    Evdokimov, Pavel; Kudryavtsev, Alexey; Ilgisonis, Ekaterina; Ponomarenko, Elena; Lisitsa, Andrey

    2016-02-18

    Keeping up with journal articles on a daily basis is an important activity of scientists engaged in biomedical research. Usually, journal articles and papers in the field of biomedicine are accessed through the Medline/PubMed electronic library. In the process of navigating PubMed, researchers unknowingly generate user-specific reading profiles that can be shared within a social networking environment. This paper examines the structure of the social networking environment generated by PubMed users. A web browser plugin was developed to map [in Medical Subject Headings (MeSH) terms] the reading patterns of individual PubMed users. We developed a scientific social network based on the personal research profiles of readers of biomedical articles. A browser plugin is used to record the digital object identifier or PubMed ID of web pages. Recorded items are posted on the activity feed and automatically mapped to PubMed abstract. Within the activity feed a user can trace back previously browsed articles and insert comments. By calculating the frequency with which specific MeSH occur, the research interests of PubMed users can be visually represented with a tag cloud. Finally, research profiles can be searched for matches between network users. A social networking environment was created using MeSH terms to map articles accessed through the Medline/PubMed online library system. In-network social communication is supported by the recommendation of articles and by matching users with similar scientific interests. The system is available at http://bioknol.org/en/.

  11. Publication Trends in Acupuncture Research: A 20-Year Bibliometric Analysis Based on PubMed

    PubMed Central

    Dong, Ming; Zhou, Kehua; Mita, Carol; Liu, Jianping; Wayne, Peter M.

    2016-01-01

    Objective Acupuncture has become popular and widely practiced in many countries around the world. Despite the large amount of acupuncture-related literature that has been published, broader trends in the prevalence and scope of acupuncture research remain underexplored. The current study quantitatively analyzes trends in acupuncture research publications in the past 20 years. Methods A bibliometric approach was used to search PubMed for all acupuncture-related research articles including clinical and animal studies. Inclusion criteria were articles published between 1995 and 2014 with sufficient information for bibliometric analyses. Rates and patterns of acupuncture publication within the 20 year observational period were estimated, and compared with broader publication rates in biomedicine. Identified eligible publications were further analyzed with respect to study type/design, clinical condition addressed, country of origin, and journal impact factor. Results A total of 13,320 acupuncture-related publications were identified using our search strategy and eligibility criteria. Regression analyses indicated an exponential growth in publications over the past two decades, with a mean annual growth rate of 10.7%. This compares to a mean annual growth rate of 4.5% in biomedicine. A striking trend was an observed increase in the proportion of randomized clinical trials (RCTs), from 7.4% in 1995 to 20.3% in 2014, exceeding the 4.5% proportional growth of RCTs in biomedicine. Over the 20 year period, pain was consistently the most common focus of acupuncture research (37.9% of publications). Other top rankings with respect to medical focus were arthritis, neoplasms/cancer, pregnancy or labor, mood disorders, stroke, nausea/vomiting, sleep, and paralysis/palsy. Acupuncture research was conducted in 60 countries, with the top 3 contributors being China (47.4%), United States (17.5%), and United Kingdom (8.2%). Retrieved articles were published mostly in complementary and

  12. Publication Trends in Acupuncture Research: A 20-Year Bibliometric Analysis Based on PubMed.

    PubMed

    Ma, Yan; Dong, Ming; Zhou, Kehua; Mita, Carol; Liu, Jianping; Wayne, Peter M

    2016-01-01

    Acupuncture has become popular and widely practiced in many countries around the world. Despite the large amount of acupuncture-related literature that has been published, broader trends in the prevalence and scope of acupuncture research remain underexplored. The current study quantitatively analyzes trends in acupuncture research publications in the past 20 years. A bibliometric approach was used to search PubMed for all acupuncture-related research articles including clinical and animal studies. Inclusion criteria were articles published between 1995 and 2014 with sufficient information for bibliometric analyses. Rates and patterns of acupuncture publication within the 20 year observational period were estimated, and compared with broader publication rates in biomedicine. Identified eligible publications were further analyzed with respect to study type/design, clinical condition addressed, country of origin, and journal impact factor. A total of 13,320 acupuncture-related publications were identified using our search strategy and eligibility criteria. Regression analyses indicated an exponential growth in publications over the past two decades, with a mean annual growth rate of 10.7%. This compares to a mean annual growth rate of 4.5% in biomedicine. A striking trend was an observed increase in the proportion of randomized clinical trials (RCTs), from 7.4% in 1995 to 20.3% in 2014, exceeding the 4.5% proportional growth of RCTs in biomedicine. Over the 20 year period, pain was consistently the most common focus of acupuncture research (37.9% of publications). Other top rankings with respect to medical focus were arthritis, neoplasms/cancer, pregnancy or labor, mood disorders, stroke, nausea/vomiting, sleep, and paralysis/palsy. Acupuncture research was conducted in 60 countries, with the top 3 contributors being China (47.4%), United States (17.5%), and United Kingdom (8.2%). Retrieved articles were published mostly in complementary and alternative medicine (CAM

  13. Growth impairment shows an age-dependent pattern in boys with chronic kidney disease.

    PubMed

    Zivicnjak, Miroslav; Franke, Doris; Filler, Guido; Haffner, Dieter; Froede, Kerstin; Nissel, Richard; Haase, Sanny; Offner, Gisela; Ehrich, Jochen H H; Querfeld, Uwe

    2007-03-01

    The impact of chronological age on longitudinal body growth from early childhood through adolescence using detailed anthropometric methods has not yet been studied in children with chronic kidney disease (CKD). We have evaluated growth failure by measuring four components of linear growth: body height (HT), sitting height (SHT), arm length (AL) and leg length (LL). Data were prospectively collected for up to 7 years on 190 boys (3-21 years old) with congenital or hereditary CKD (all had developed at least stage 2 CKD by the age of 10 years). Patients showed the most severe growth failure in early childhood, followed by an acceleration in growth in pre-puberty, a slowing-down of growth at puberty, as expected, and thereafter a late speeding-up of growth until early adulthood. This pattern was observed irrespective of the degree of CKD and different treatment modalities, such as conservative treatment, recombinant human growth hormone (rhGH) therapy or transplantation. LL showed the most dynamic growth changes of all the parameters evaluated and emerged as the best indicator of statural growth in children with CKD. A specific age-dependent pattern of physical growth was identified in pediatric male CKD patients. This growth pattern should be considered in the evaluation of individual growth and the assessment of treatment efficacy such as rhGH therapy.

  14. Optical Characterization of Thick Growth Orientation-Patterned Gallium Arsenide

    DTIC Science & Technology

    2006-03-15

    some region of non-patterned material. Figure 6 shows sample 2 next to a ballpoint pen tip. Most of the area is patterned, while a prominent band...OPGaAs) is a promising nonlinear conversion material because it has broad transparency and can be engineered for specific pump laser and output...Additional defense specific applications using laser output in the 2-µm to 5-μm wavelength region include target acquisition, recognition, and designation

  15. Gaps in affiliation indexing in Scopus and PubMed

    PubMed Central

    Schmidt, Cynthia M.; Cox, Roxanne; Fial, Alissa V.; Hartman, Teresa L.; Magee, Martha L.

    2016-01-01

    Objective The authors sought to determine whether unexpected gaps existed in Scopus's author affiliation indexing of publications written by the University of Nebraska Medical Center or Nebraska Medicine (UNMC/NM) authors during 2014. Methods First, we compared Scopus affiliation identifier search results to PubMed affiliation keyword search results. Then, we searched Scopus using affiliation keywords (UNMC, etc.) and compared the results to PubMed affiliation keyword and Scopus affiliation identifier searches. Results We found that Scopus's records for approximately 7% of UNMC/NM authors' publications lacked appropriate UNMC/NM author affiliation identifiers, and many journals' publishers were supplying incomplete author affiliation information to PubMed. Conclusions Institutions relying on Scopus to track their impact should determine whether Scopus's affiliation identifiers will, in fact, identify all articles published by their authors and investigators. PMID:27076801

  16. Gaps in affiliation indexing in Scopus and PubMed.

    PubMed

    Schmidt, Cynthia M; Cox, Roxanne; Fial, Alissa V; Hartman, Teresa L; Magee, Martha L

    2016-04-01

    The authors sought to determine whether unexpected gaps existed in Scopus's author affiliation indexing of publications written by the University of Nebraska Medical Center or Nebraska Medicine (UNMC/NM) authors during 2014. First, we compared Scopus affiliation identifier search results to PubMed affiliation keyword search results. Then, we searched Scopus using affiliation keywords (UNMC, etc.) and compared the results to PubMed affiliation keyword and Scopus affiliation identifier searches. We found that Scopus's records for approximately 7% of UNMC/NM authors' publications lacked appropriate UNMC/NM author affiliation identifiers, and many journals' publishers were supplying incomplete author affiliation information to PubMed. Institutions relying on Scopus to track their impact should determine whether Scopus's affiliation identifiers will, in fact, identify all articles published by their authors and investigators.

  17. Growth Anisotropy and Pattern Formation during Metal Epitaxy

    NASA Astrophysics Data System (ADS)

    Poelsema, Bene; Jorritsma, Louis C.; Rosenfeld, Georg

    1997-03-01

    The homoepitaxial growth on Cu(001) has been investigated by He atom beam scattering (TEAS) and High Resolution Low Energy Electron Diffraction (SPA-LEED). In the temperature regime below 300 K the growth initially starts `layer-by-layer', but turns gradually into multi-layer growth at higher coverage. Analysis of SPA-LEED peak profiles reveals that as growth proceeds checkerboard-like arrangements of mound-like structures are formed. The sides of the mounds are composed of <11n>-facets. The origin of such an arrangement has been traced back to laterally anisotropic advance rates of adatomisland edges in combination with a finite energy barrier for descending from a step edge.

  18. Reliability of Beta angle in assessing true anteroposterior apical base discrepancy in different growth patterns.

    PubMed

    Sundareswaran, Shobha; Kumar, Vinay

    2015-01-01

    Beta angle as a skeletal anteroposterior dysplasia indicator is known to be useful in evaluating normodivergent growth patterns. Hence, we compared and verified the accuracy of Beta angle in predicting sagittal jaw discrepancy among subjects with hyperdivergent, hypodivergent and normodivergent growth patterns. Lateral cephalometric radiographs of 179 patients belonging to skeletal Classes I, II, and III were further divided into normodivergent, hyperdivergent, and hypodivergent groups based on their vertical growth patterns. Sagittal dysplasia indicators - angle ANB, Wits appraisal, and Beta angle values were measured and tabulated. The perpendicular point of intersection on line CB (Condylion-Point B) in Beta angle was designated as 'X' and linear dimension XB was evaluated. Statistically significant increase was observed in the mean values of Beta angle and XB distance in the vertical growth pattern groups of both skeletal Class I and Class II patients thus pushing them toward Class III and Class I, respectively. Beta angle is a reliable indicator of sagittal dysplasia in normal and horizontal patterns of growth. However, vertical growth patterns significantly increased Beta angle values, thus affecting their reliability as a sagittal discrepancy assessment tool. Hence, Beta angle may not be a valid tool for assessment of sagittal jaw discrepancy in patients exhibiting vertical growth patterns with skeletal Class I and Class II malocclusions. Nevertheless, Class III malocclusions having the highest Beta angle values were unaffected.

  19. Hormone-Mediated Pattern Formation in Seedling of Plants: a Competitive Growth Dynamics Model

    NASA Astrophysics Data System (ADS)

    Kawaguchi, Satoshi; Mimura, Masayasu; Ohya, Tomoyuki; Oikawa, Noriko; Okabe, Hirotaka; Kai, Shoichi

    2001-10-01

    An ecologically relevant pattern formation process mediated by hormonal interactions among growing seedlings is modeled based on the experimental observations on the effects of indole acetic acid, which can act as an inhibitor and activator of root growth depending on its concentration. In the absence of any lateral root with constant hormone-sensitivity, the edge effect phenomenon is obtained depending on the secretion rate of hormone from the main root. Introduction of growth-stage-dependent hormone-sensitivity drastically amplifies the initial randomness, resulting in spatially irregular macroscopic patterns. When the lateral root growth is introduced, periodic patterns are obtained whose periodicity depends on the length of lateral roots. The growth-stage-dependent hormone-sensitivity and the lateral root growth are crucial for macroscopic periodic-pattern formation.

  20. Reliability of Beta angle in assessing true anteroposterior apical base discrepancy in different growth patterns

    PubMed Central

    Sundareswaran, Shobha; Kumar, Vinay

    2015-01-01

    Introduction: Beta angle as a skeletal anteroposterior dysplasia indicator is known to be useful in evaluating normodivergent growth patterns. Hence, we compared and verified the accuracy of Beta angle in predicting sagittal jaw discrepancy among subjects with hyperdivergent, hypodivergent and normodivergent growth patterns. Materials and Methods: Lateral cephalometric radiographs of 179 patients belonging to skeletal Classes I, II, and III were further divided into normodivergent, hyperdivergent, and hypodivergent groups based on their vertical growth patterns. Sagittal dysplasia indicators - angle ANB, Wits appraisal, and Beta angle values were measured and tabulated. The perpendicular point of intersection on line CB (Condylion-Point B) in Beta angle was designated as ‘X’ and linear dimension XB was evaluated. Results: Statistically significant increase was observed in the mean values of Beta angle and XB distance in the vertical growth pattern groups of both skeletal Class I and Class II patients thus pushing them toward Class III and Class I, respectively. Conclusions: Beta angle is a reliable indicator of sagittal dysplasia in normal and horizontal patterns of growth. However, vertical growth patterns significantly increased Beta angle values, thus affecting their reliability as a sagittal discrepancy assessment tool. Hence, Beta angle may not be a valid tool for assessment of sagittal jaw discrepancy in patients exhibiting vertical growth patterns with skeletal Class I and Class II malocclusions. Nevertheless, Class III malocclusions having the highest Beta angle values were unaffected. PMID:25810649

  1. Growth patterns of red pine on fine-textured soils.

    Treesearch

    David H. Alban; Donald H. Prettyman; Gary J. Brand

    1987-01-01

    Compares growth of 28- to 49-year-old red pine plantations on sandy and fine-textured soils. Red pine growing on these two contrasting soils did not differ in bole form, live crown ratio, or mortality, and tree growth predicted by models (STEMS and REDPINE) developed from trees growing on sandy soils worked equally well for trees growing on fine-textured soils.

  2. Water Control on Vegetation Growth Pattern in Eurasia from GRACE

    NASA Astrophysics Data System (ADS)

    A, G.; Velicogna, I.; Kimball, J. S.; Kim, Y.

    2014-12-01

    High latitude ecosystem productivity is constrained by cold temperature and moisture limitations to plant growth, while these environmental restrictions may be changing with global warming. Satellite data driven assessments indicate that over the past three decades, rapid warming in the northern high latitudes has resulted in earlier and longer potential growing seasons and widespread greening, due to general relaxation of cold temperature constraints to vegetation productivity. However, warming may have also increased water stress limitations to growth. In this study, we use GRACE (Gravity Recovery and Climate Experiment) derived total water storage (TWS), 2-m air temperature (T) from ERA-interim reanalysis, normalized difference vegetation index (NDVI) data from MODIS (Collection 5) and satellite data driven vegetation gross primary productivity (GPP) estimates as surrogates for vegetation growth, for the period August 2002-December 2013 to evaluate terrestrial water supply controls to vegetation growth changes over the three major river basins of northern Eurasia. We find that during the analyzed period, the apparent growth response follows regional vegetation, moisture and temperature gradients and is spatially complex. In the drier southwest characterized by grassland, vegetation growth is mainly controlled by TWS availability. In the central region, dominated by cold temperature and water limited boreal forest, T is the main control on vegetation growth. In the Lena basin, where vegetation includes both boreal forest and water limited grassland, both T and TWS impact vegetation growth. We suggest that GRACE TWS estimates provide reliable observational constraints on water availability to vegetation that supplement sparse soil moisture observations and satellite precipitation estimates with unknown bias.

  3. Numerical computations of faceted pattern formation in snow crystal growth.

    PubMed

    Barrett, John W; Garcke, Harald; Nürnberg, Robert

    2012-07-01

    Faceted growth of snow crystals leads to a rich diversity of forms with remarkable sixfold symmetry. Snow crystal structures result from diffusion-limited crystal growth in the presence of anisotropic surface energy and anisotropic attachment kinetics. It is by now well understood that the morphological stability of ice crystals strongly depends on supersaturation, crystal size, and temperature. Until very recently it was very difficult to perform numerical simulations of this highly anisotropic crystal growth. In particular, obtaining facet growth in combination with dendritic branching is a challenging task. We present numerical simulations of snow crystal growth in two and three spacial dimensions using a computational method recently introduced by the present authors. We present both qualitative and quantitative computations. In particular, a linear relationship between tip velocity and supersaturation is observed. In our computations, surface energy effects, although small, have a pronounced effect on crystal growth. We compute solid plates, solid prisms, hollow columns, needles, dendrites, capped columns, and scrolls on plates. Although all these forms appear in nature, it is a significant challenge to reproduce them with the help of numerical simulations for a continuum model.

  4. Growth Patterns in Children with Sickle Cell Anemia during Puberty

    PubMed Central

    Rhodes, Melissa; Akohoue, Sylvie A.; Shankar, Sadhna M.; Fleming, Irma; An, Angel; Yu, Chung; Acra, Sari; Buchowski, Maciej S.

    2009-01-01

    Background Previous studies of children with homozygous sickle cell anemia (SCA) show impaired growth and maturation. The correlation of this suboptimal growth with metabolic and hematological factors during puberty is poorly understood. Procedure We studied a group of pre-adolescent children with SCA (19 males, 14 females) and healthy controls (16 males, 15 females) matched for race, sex, body size, and pubertal development. Height, weight, body mass index (BMI), and body composition changes were longitudinally assessed over a 2-year period and compared between the groups and with Z scores based on US growth charts. These changes were correlated with hemoglobin concentration and with energy expenditure measured using indirect whole-room calorimetry. Results Children with SCA progressed through puberty slower than control children. While, after 2 years, pubertal males with SCA were shorter, their annual increases in weight were not different from controls. The mean fat free mass (FFM) increments were significantly less in males and females with SCA than in control children. In males with SCA, growth in height declined over time and was significantly slower than in matched controls (p<0.05). Conclusion Growth delays were present during puberty in children with SCA. Decreased growth velocity in children with SCA was independently associated with decreased hemoglobin concentration and increased total energy expenditure. PMID:19544390

  5. Simulation of growth rate and deposition profile on the periodically patterned substrate

    NASA Astrophysics Data System (ADS)

    Baek, Byung-Joon; Kang, Sung-Ju; Kim, Jin-Taek; Pak, Bockchoon; Lee, Cheul-Ro

    2007-06-01

    The growth of GaN on the patterned substances has proven favorable to achieve thick, crack-free GaN layers. Based on these methods, we specially designed periodically patterned Si substrate process, which is referred to as lateral epitaxy on patterned Si substrate (LEPS). High crystalline quality GaN are obtained by using this technique. In this paper, numerical modeling of transport and reaction of species is performed to estimate the growth rate of GaN from the reaction of trimethyl gallium (TMG) and ammonia. The effect of fabricated structure of feature scale model will be predicted by using the topography simulator, and deposition profile of the GaN on the pattern will be discussed. The effect of flow conditions and pattern shape and periodicity will also be addressed, which can be critical for the quality of crystal growth. The dependency of step coverage and conformality of patterned mask will also be discussed.

  6. Discovering biomedical semantic relations in PubMed queries for information retrieval and database curation.

    PubMed

    Huang, Chung-Chi; Lu, Zhiyong

    2016-01-01

    Identifying relevant papers from the literature is a common task in biocuration. Most current biomedical literature search systems primarily rely on matching user keywords. Semantic search, on the other hand, seeks to improve search accuracy by understanding the entities and contextual relations in user keywords. However, past research has mostly focused on semantically identifying biological entities (e.g. chemicals, diseases and genes) with little effort on discovering semantic relations. In this work, we aim to discover biomedical semantic relations in PubMed queries in an automated and unsupervised fashion. Specifically, we focus on extracting and understanding the contextual information (or context patterns) that is used by PubMed users to represent semantic relations between entities such as 'CHEMICAL-1 compared to CHEMICAL-2' With the advances in automatic named entity recognition, we first tag entities in PubMed queries and then use tagged entities as knowledge to recognize pattern semantics. More specifically, we transform PubMed queries into context patterns involving participating entities, which are subsequently projected to latent topics via latent semantic analysis (LSA) to avoid the data sparseness and specificity issues. Finally, we mine semantically similar contextual patterns or semantic relations based on LSA topic distributions. Our two separate evaluation experiments of chemical-chemical (CC) and chemical-disease (CD) relations show that the proposed approach significantly outperforms a baseline method, which simply measures pattern semantics by similarity in participating entities. The highest performance achieved by our approach is nearly 0.9 and 0.85 respectively for the CC and CD task when compared against the ground truth in terms of normalized discounted cumulative gain (nDCG), a standard measure of ranking quality. These results suggest that our approach can effectively identify and return related semantic patterns in a ranked order

  7. Discovering biomedical semantic relations in PubMed queries for information retrieval and database curation

    PubMed Central

    Huang, Chung-Chi; Lu, Zhiyong

    2016-01-01

    Identifying relevant papers from the literature is a common task in biocuration. Most current biomedical literature search systems primarily rely on matching user keywords. Semantic search, on the other hand, seeks to improve search accuracy by understanding the entities and contextual relations in user keywords. However, past research has mostly focused on semantically identifying biological entities (e.g. chemicals, diseases and genes) with little effort on discovering semantic relations. In this work, we aim to discover biomedical semantic relations in PubMed queries in an automated and unsupervised fashion. Specifically, we focus on extracting and understanding the contextual information (or context patterns) that is used by PubMed users to represent semantic relations between entities such as ‘CHEMICAL-1 compared to CHEMICAL-2.’ With the advances in automatic named entity recognition, we first tag entities in PubMed queries and then use tagged entities as knowledge to recognize pattern semantics. More specifically, we transform PubMed queries into context patterns involving participating entities, which are subsequently projected to latent topics via latent semantic analysis (LSA) to avoid the data sparseness and specificity issues. Finally, we mine semantically similar contextual patterns or semantic relations based on LSA topic distributions. Our two separate evaluation experiments of chemical-chemical (CC) and chemical–disease (CD) relations show that the proposed approach significantly outperforms a baseline method, which simply measures pattern semantics by similarity in participating entities. The highest performance achieved by our approach is nearly 0.9 and 0.85 respectively for the CC and CD task when compared against the ground truth in terms of normalized discounted cumulative gain (nDCG), a standard measure of ranking quality. These results suggest that our approach can effectively identify and return related semantic patterns in a ranked

  8. pubmed.mineR: an R package with text-mining algorithms to analyse PubMed abstracts.

    PubMed

    Rani, Jyoti; Shah, A B Rauf; Ramachandran, Srinivasan

    2015-10-01

    The PubMed literature database is a valuable source of information for scientific research. It is rich in biomedical literature with more than 24 million citations. Data-mining of voluminous literature is a challenging task. Although several text-mining algorithms have been developed in recent years with focus on data visualization, they have limitations such as speed, are rigid and are not available in the open source. We have developed an R package, pubmed.mineR, wherein we have combined the advantages of existing algorithms, overcome their limitations, and offer user flexibility and link with other packages in Bioconductor and the Comprehensive R Network (CRAN) in order to expand the user capabilities for executing multifaceted approaches. Three case studies are presented, namely, 'Evolving role of diabetes educators', 'Cancer risk assessment' and 'Dynamic concepts on disease and comorbidity' to illustrate the use of pubmed.mineR. The package generally runs fast with small elapsed times in regular workstations even on large corpus sizes and with compute intensive functions. The pubmed.mineR is available at http://cran.rproject. org/web/packages/pubmed.mineR.

  9. An automatic method to generate domain-specific investigator networks using PubMed abstracts.

    PubMed

    Yu, Wei; Yesupriya, Ajay; Wulf, Anja; Qu, Junfeng; Gwinn, Marta; Khoury, Muin J

    2007-06-20

    Collaboration among investigators has become critical to scientific research. This includes ad hoc collaboration established through personal contacts as well as formal consortia established by funding agencies. Continued growth in online resources for scientific research and communication has promoted the development of highly networked research communities. Extending these networks globally requires identifying additional investigators in a given domain, profiling their research interests, and collecting current contact information. We present a novel strategy for building investigator networks dynamically and producing detailed investigator profiles using data available in PubMed abstracts. We developed a novel strategy to obtain detailed investigator information by automatically parsing the affiliation string in PubMed records. We illustrated the results by using a published literature database in human genome epidemiology (HuGE Pub Lit) as a test case. Our parsing strategy extracted country information from 92.1% of the affiliation strings in a random sample of PubMed records and in 97.0% of HuGE records, with accuracies of 94.0% and 91.0%, respectively. Institution information was parsed from 91.3% of the general PubMed records (accuracy 86.8%) and from 94.2% of HuGE PubMed records (accuracy 87.0). We demonstrated the application of our approach to dynamic creation of investigator networks by creating a prototype information system containing a large database of PubMed abstracts relevant to human genome epidemiology (HuGE Pub Lit), indexed using PubMed medical subject headings converted to Unified Medical Language System concepts. Our method was able to identify 70-90% of the investigators/collaborators in three different human genetics fields; it also successfully identified 9 of 10 genetics investigators within the PREBIC network, an existing preterm birth research network. We successfully created a web-based prototype capable of creating domain

  10. An automatic method to generate domain-specific investigator networks using PubMed abstracts

    PubMed Central

    Yu, Wei; Yesupriya, Ajay; Wulf, Anja; Qu, Junfeng; Gwinn, Marta; Khoury, Muin J

    2007-01-01

    Background Collaboration among investigators has become critical to scientific research. This includes ad hoc collaboration established through personal contacts as well as formal consortia established by funding agencies. Continued growth in online resources for scientific research and communication has promoted the development of highly networked research communities. Extending these networks globally requires identifying additional investigators in a given domain, profiling their research interests, and collecting current contact information. We present a novel strategy for building investigator networks dynamically and producing detailed investigator profiles using data available in PubMed abstracts. Results We developed a novel strategy to obtain detailed investigator information by automatically parsing the affiliation string in PubMed records. We illustrated the results by using a published literature database in human genome epidemiology (HuGE Pub Lit) as a test case. Our parsing strategy extracted country information from 92.1% of the affiliation strings in a random sample of PubMed records and in 97.0% of HuGE records, with accuracies of 94.0% and 91.0%, respectively. Institution information was parsed from 91.3% of the general PubMed records (accuracy 86.8%) and from 94.2% of HuGE PubMed records (accuracy 87.0). We demonstrated the application of our approach to dynamic creation of investigator networks by creating a prototype information system containing a large database of PubMed abstracts relevant to human genome epidemiology (HuGE Pub Lit), indexed using PubMed medical subject headings converted to Unified Medical Language System concepts. Our method was able to identify 70–90% of the investigators/collaborators in three different human genetics fields; it also successfully identified 9 of 10 genetics investigators within the PREBIC network, an existing preterm birth research network. Conclusion We successfully created a web-based prototype

  11. Pattern of growth of very low birth weight preterm infants, assessed using the WHO Growth Standards, is associated with neurodevelopment.

    PubMed

    Nash, Andrea; Dunn, Michael; Asztalos, Elizabeth; Corey, Mary; Mulvihill-Jory, Bridget; O'Connor, Deborah L

    2011-08-01

    Several Canadian professional organizations recently recommended that the growth of preterm infants be monitored using the World Health Organization Growth Standards (WHO-GS) after hospital discharge. The WHO-GS are a prescriptive set of growth charts that describe how term infants should grow under ideal environmental conditions. Whether preterm infants following this pattern of growth have better outcomes than infants that do not has yet to be evaluated. Our aim was to determine whether the pattern of growth of very low birth weight (VLBW) infants during the first 2 years, assessed using the WHO-GS or the traditional Centers for Disease Control and Prevention reference growth charts (CDC-RGC), is associated with neurodevelopment. Pattern of weight, length, and head circumference gain of appropriate-for-gestation VLBW preterm infants (n = 289) from birth to 18-24 months corrected age was classified, using the WHO-GS and CDC-RGC, as sustained (change in Z-score ≤1 SD), decelerated (decline >1 SD), or accelerated (incline >1 SD). Development was assessed using the Bayley Scales of Infant and Toddler Development (BSID)-III at 18-24 months corrected age. Using the WHO-GS, children with a decelerated pattern of weight gain had lower cognitive (10 points), language (6 points), and motor (4 points) scores than infants with sustained weight gain (p < 0.05), even after adjustment for morbidities. No association was found using the CDC-RGC. In conclusion, a decelerated pattern of weight gain, determined with the WHO-GS, but not the CDC-GRC, is associated with poorer neurodevelopment scores on the BSID-III than a pattern of sustained growth.

  12. Morphological Changes in Growth Phenomena of Bacterial Colony Patterns

    NASA Astrophysics Data System (ADS)

    Ohgiwari, Masahiro; Matsushita, Mitsugu; Matsuyama, Tohey

    1992-03-01

    We have investigated the morphological change in colonies of bacteria called Bacillus subtilis. Patterns of colonies grown on the surface of thin agar plates were found to change drastically through the variation of environmental conditions; concentrations of nutrient Cn and agar Ca in the agar medium. They were classified into five types; DLA-like, Eden-like, DBM-like, intermediate and homogeneously spreading. The active movement of individual bacterial cells was seen in expanding periphery of a colony at intermediate and low Ca (soft agar medium). Such bacterial cell movements are found to induce the shift from DLA- and Eden-like patterns to those found for softer agar medium. Physical implication of the pattern changes is discussed.

  13. Prediction of fatigue crack-growth patterns and lives in three-dimensional cracked bodies

    NASA Technical Reports Server (NTRS)

    Newman, J. C., Jr.; Raju, I. S.

    1986-01-01

    Fatigue crack growth patterns and lives for surface cracks, surface cracks at holes, and corner cracks at holes in three dimensional bodies were predicted using linear-elastic fracture mechanics concepts that were modified to account for crack-closure behavior. The predictions were made by using stress intensity factor equations for these crack configurations and the fatigue crack-growth (delta K against rate) relationship for the material of interest. The crack configurations were subjected to constant-amplitude fatigue loading under either remote tension or bending loads. The predicted crack growth patterns and crack growth lives for aluminum alloys agreed well with test data from the literature.

  14. Prediction of fatigue crack-growth patterns and lives in three-dimensional cracked bodies

    NASA Technical Reports Server (NTRS)

    Newman, J. C., Jr.; Raju, I. S.

    1984-01-01

    Fatigue crack growth patterns and lives for surface cracks, surface cracks at holes, and corner cracks at holes in three dimensional bodies were predicted using linear-elastic fracture mechanics concepts that were modified to account for crack-closure behavior. The predictions were made by using stress intensity factor equations for these crack configurations and the fatigue crack-growth (delta K against rate) relationship for the material of interest. The crack configurations were subjected to constant-amplitude fatigue loading under either remote tension or bending loads. The predicted crack growth patterns and crack growth lives for aluminum alloys agreed well with test data from the literature.

  15. Phycomyces: irregular growth patterns in stage IVb sporangiophores

    PubMed Central

    1981-01-01

    Net rotation and net elongation of a stage IVb Phycomyces growing zone were simultaneously measured minute by minute with a photographic apparatus coupled with a rotating stage. A direct correlation between a growth response and a twist response after either a light stimulus or a house stimulus was found. There were significant irregularities in growth rate in both the elongation and rotation that were not a result of measurement error; these irregularities were poorly, if at all, correlated. We believe that these fluctuations reflect the underlying molecular mechanism of cell wall synthesis. PMID:7205194

  16. Increased monolayer domain size and patterned growth of tungsten disulfide through controlling surface energy of substrates

    NASA Astrophysics Data System (ADS)

    Godin, Kyle; Kang, Kyungnam; Fu, Shichen; Yang, Eui-Hyeok

    2016-08-01

    We report a surface energy-controlled low-pressure chemical vapor deposition growth of WS2 monolayers on SiO2 using pre-growth oxygen plasma treatment of substrates, facilitating increased monolayer surface coverage and patterned growth without lithography. Oxygen plasma treatment of the substrate caused an increase in the average domain size of WS2 monolayers by 78%  ±  2% while having a slight reduction in nucleation density, which translates to increased monolayer surface coverage. This substrate effect on growth was exploited to grow patterned WS2 monolayers by patterned plasma treatment on patterned substrates and by patterned source material with resolutions less than 10 µm. Contact angle-based surface energy measurements revealed a dramatic increase in polar surface energy. A growth model was proposed with lowered activation energies for growth and increased surface diffusion length consistent with the range of results observed. WS2 samples grown with and without oxygen plasma were similar high quality monolayers verified through transmission electron microscopy, selected area electron diffraction, atomic force microscopy, Raman, and photoluminescence measurements. This technique enables the production of large-grain size, patterned WS2 without a post-growth lithography process, thereby providing clean surfaces for device applications.

  17. Catch-up growth follows an abnormal pattern in experimental renal insufficiency and growth hormone treatment normalizes it.

    PubMed

    Molinos, I; Santos, F; Carbajo-Perez, E; Garcia, E; Rodriguez, J; Garcia-Alvarez, O; Gil, H; Ordoñez, F A; Loredo, V; Mallada, L

    2006-12-01

    The primary goal of this study was to determine if the ability to undergo catch-up growth following a transient injury is preserved in an experimental model of moderate chronic renal failure (CRF) and the effect of growth hormone (GH) administration on such phenomenon. Young rats were subtotally nephrectomized (days 0 and 4) (Nx). From days 11 to 13, food intake was restricted in subgroups of Nx and control (C) rats (NxR and CR). After refeeding, subgroups of NxR and CR rats received GH from days 14 to 20 (NxRGH and CRGH). Rats were killed on days 14 (C, CR, Nx, NxR), 17 and 21 (C, CR, CRGH, Nx, NxR, NxRGH), and 36 (C, CR, Nx, NxR). Longitudinal growth rate was measured by osseous front advance in the proximal tibiae. With refeeding, growth rate of CR, NxR, and NXrGH rats became significantly greater than that of C, indicating catch-up growth. This occurred later and with lower growth rate in NxR than in CR rats, whereas the characteristics of catch-up growth in CR and NxRGH animals were similar. Changes in growth rate were associated with modifications in the morphology and proliferative activity of growth cartilage. We conclude that catch-up growth occurs in renal insufficiency but follows a different pattern from that observed with normal renal function. GH treatment normalizes the pattern of catch-up growth in CRF. Changes in growth velocity are associated to modifications in the structure and dynamics of growth cartilage.

  18. PubMed and beyond: a survey of web tools for searching biomedical literature

    PubMed Central

    Lu, Zhiyong

    2011-01-01

    The past decade has witnessed the modern advances of high-throughput technology and rapid growth of research capacity in producing large-scale biological data, both of which were concomitant with an exponential growth of biomedical literature. This wealth of scholarly knowledge is of significant importance for researchers in making scientific discoveries and healthcare professionals in managing health-related matters. However, the acquisition of such information is becoming increasingly difficult due to its large volume and rapid growth. In response, the National Center for Biotechnology Information (NCBI) is continuously making changes to its PubMed Web service for improvement. Meanwhile, different entities have devoted themselves to developing Web tools for helping users quickly and efficiently search and retrieve relevant publications. These practices, together with maturity in the field of text mining, have led to an increase in the number and quality of various Web tools that provide comparable literature search service to PubMed. In this study, we review 28 such tools, highlight their respective innovations, compare them to the PubMed system and one another, and discuss directions for future development. Furthermore, we have built a website dedicated to tracking existing systems and future advances in the field of biomedical literature search. Taken together, our work serves information seekers in choosing tools for their needs and service providers and developers in keeping current in the field. Database URL: http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/search PMID:21245076

  19. PubMed Central Canada: Beyond an Open Access Repository?

    ERIC Educational Resources Information Center

    Nariani, Rajiv

    2013-01-01

    PubMed Central Canada (PMC Canada) represents a partnership between the Canadian Institutes of Health Research (CIHR), the National Research Council's Canada Institute for Scientific and Technical Information (NRC-CISTI), and the National Library of Medicine of the US. The present study was done to gauge faculty awareness about the CIHR Policy on…

  20. PubMed Central Canada: Beyond an Open Access Repository?

    ERIC Educational Resources Information Center

    Nariani, Rajiv

    2013-01-01

    PubMed Central Canada (PMC Canada) represents a partnership between the Canadian Institutes of Health Research (CIHR), the National Research Council's Canada Institute for Scientific and Technical Information (NRC-CISTI), and the National Library of Medicine of the US. The present study was done to gauge faculty awareness about the CIHR Policy on…

  1. Growth patterns of fossil vertebrates as deduced from bone microstructure: case studies from India.

    PubMed

    Ray, S; Mukherjee, D; Bandyopadhyay, S

    2009-11-01

    Bone microstructure is affected by ontogeny, phylogeny, biomechanics and environments. These aspects of life history of an extinct animal, especially its growth patterns, may be assessed as fossil bone generally maintains its histological integrity. Recent studies on the bone histology of fossil vertebrates from India encompass different types of temnospondyls and dicynodonts from different Permian and Triassic horizons. The examined taxa show that they had distinct bone histology and varied growth patterns. The Early Triassic trematosaurids had an overall fast growth, which contrasts with that of the Middle and Late Triassic temnospondyl taxa examined. The dicynodonts on the other hand, were characterized by an overall fast growth with periodic interruptions, variable growth rates dependent on ontogeny and indeterminate growth strategy. A comparative study encompassing several neotherapsid genera including the dicynodonts shows signifi cant evolutionary trends towards determinate growth strategy and reduced developmental plasticity.

  2. Growth pattern from birth to adulthood in African pygmies of known age

    PubMed Central

    Rozzi, Fernando V. Ramirez; Koudou, Yves; Froment, Alain; Le Bouc, Yves; Botton, Jérémie

    2015-01-01

    The African pygmy phenotype stems from genetic foundations and is considered to be the product of a disturbance in the growth hormone–insulin-like growth factor (GH–IGF) axis. However, when and how the pygmy phenotype is acquired during growth remains unknown. Here we describe growth patterns in Baka pygmies based on two longitudinal studies of individuals of known age, from the time of birth to the age of 25 years. Body size at birth among the Baka is within standard limits, but their growth rate slows significantly during the first two years of life. It then more or less follows the standard pattern, with a growth spurt at adolescence. Their life history variables do not allow the Baka to be distinguished from other populations. Therefore, the pygmy phenotype in the Baka is the result of a change in growth that occurs during infancy, which differentiates them from East African pygmies revealing convergent evolution. PMID:26218408

  3. Concern noted: A descriptive study of editorial expressions of concern in PubMed and PubMed Central

    PubMed Central

    Vaught, Melissa; Jordan, Diana C.; Bastian, Hilda

    2017-01-01

    Background An editorial expression of concern (EEoC) is issued by editors or publishers to draw attention to potential problems in a publication, without itself constituting a retraction or correction. Methods We searched PubMed, PubMed Central (PMC), and Google Scholar to identify EEoCs issued for publications in PubMed and PMC up to 22 August 2016. We also searched the archives of the Retraction Watch blog, some journal and publisher websites, and studies of EEoCs. In addition, we searched for retractions of EEoCs and affected articles in PubMed up to 8 December 2016. We analyzed overall historical trends, as well as reported reasons and subsequent editorial actions related to EEoCs issued between August 2014 and August 2016. Results After screening 5,076 records, we identified 230 EEoCs that affect 300 publications indexed in PubMed, the earliest issued in 1985. Half of the primary EEoCs were issued between 2014 and 2016 (52%). We found evidence of some EEoCs that had been removed by the publisher without leaving a record and some were not submitted for PubMed or PMC indexing. A minority of publications affected by EEoCs had been retracted by early December 2016 (25%). For the subset of 92 EEoCs issued between August 2014 and August 2016, affecting 99 publications, the rate of retraction was similar (29%). The majority of EEoCs were issued because of concerns with validity of data, methods, or interpretation of the publication (68%), and 31% of cases remained open. Issues with images were raised in 40% of affected publications. Ongoing monitoring after the study identified another 17 EEoCs to year’s end in 2016, increasing the number of EEoCs to 247 and publications in PubMed known to be affected by EEoCs to 320 at the end of 2016. Conclusions EEoCs have been rare publishing events in the biomedical literature, but their use has been increasing. Most have not led to retractions, and many remain unresolved. Lack of prominence and inconsistencies in management

  4. How Complementary and Alternative Medicine Practitioners Use PubMed

    PubMed Central

    Quint-Rapoport, Mia

    2007-01-01

    Background PubMed is the largest bibliographic index in the life sciences. It is freely available online and is used by professionals and the public to learn more about medical research. While primarily intended to serve researchers, PubMed provides an array of tools and services that can help a wider readership in the location, comprehension, evaluation, and utilization of medical research. Objective This study sought to establish the potential contributions made by a range of PubMed tools and services to the use of the database by complementary and alternative medicine practitioners. Methods In this study, 10 chiropractors, 7 registered massage therapists, and a homeopath (N = 18), 11 with prior research training and 7 without, were taken through a 2-hour introductory session with PubMed. The 10 PubMed tools and services considered in this study can be divided into three functions: (1) information retrieval (Boolean Search, Limits, Related Articles, Author Links, MeSH), (2) information access (Publisher Link, LinkOut, Bookshelf ), and (3) information management (History, Send To, Email Alert). Participants were introduced to between six and 10 of these tools and services. The participants were asked to provide feedback on the value of each tool or service in terms of their information needs, which was ranked as positive, positive with emphasis, negative, or indifferent. Results The participants in this study expressed an interest in the three types of PubMed tools and services (information retrieval, access, and management), with less well-regarded tools including MeSH Database and Bookshelf. In terms of their comprehension of the research, the tools and services led the participants to reflect on their understanding as well as their critical reading and use of the research. There was universal support among the participants for greater access to complete articles, beyond the approximately 15% that are currently open access. The abstracts provided by PubMed were

  5. Nonlinear and Quasi-Simplex Patterns in Latent Growth Models

    ERIC Educational Resources Information Center

    Bianconcini, Silvia

    2012-01-01

    In the SEM literature, simplex and latent growth models have always been considered competing approaches for the analysis of longitudinal data, even if they are strongly connected and both of specific importance. General dynamic models, which simultaneously estimate autoregressive structures and latent curves, have been recently proposed in the…

  6. Annual growth patterns of baldcypress (Taxodium distichum) along salinity gradients

    USGS Publications Warehouse

    Thomas, Brenda L.; Doyle, Thomas W.; Krauss, Ken W.

    2015-01-01

    The effects of salinity on Taxodium distichum seedlings have been well documented, but few studies have examined mature trees in situ. We investigated the environmental drivers of T. distichum growth along a salinity gradient on the Waccamaw (South Carolina) and Savannah (Georgia) Rivers. On each river, T. distichum increment cores were collected from a healthy upstream site (Upper), a moderately degraded mid-reach site (Middle), and a highly degraded downstream site (Lower). Chronologies were successfully developed for Waccamaw Upper and Middle, and Savannah Middle. Correlations between standardized chronologies and environmental variables showed significant relationships between T. distichum growth and early growing season precipitation, temperature, and Palmer Drought Severity Index (PDSI). Savannah Middle chronology correlated most strongly with August river salinity levels. Both lower sites experienced suppression/release events likely in response to local anthropogenic impacts rather than regional environmental variables. The factors that affect T. distichum growth, including salinity, are strongly synergistic. As sea-level rise pushes the freshwater/saltwater interface inland, salinity becomes more limiting to T. distichum growth in tidal freshwater swamps; however, salinity impacts are exacerbated by locally imposed environmental modifications.

  7. Literature Growth and Author Productivity Patterns in Indian Physics.

    ERIC Educational Resources Information Center

    Gupta, B. M.; Sharma, Lalita; Kumar, Suresh

    1998-01-01

    Explores the applicability of selected technology diffusion models to the growth of literature in Indian and World physics (1900-50). Focuses on the applicability and validity of two forms of Lotka's Law and negative binomial distribution model to the cumulative author productivity data on Indian physics. Looks at linkages between…

  8. Phototropic growth control of nanoscale pattern formation in photoelectrodeposited Se–Te films

    PubMed Central

    Sadtler, Bryce; Burgos, Stanley P.; Batara, Nicolas A.; Beardslee, Joseph A.; Atwater, Harry A.; Lewis, Nathan S.

    2013-01-01

    Photoresponsive materials that adapt their morphologies, growth directions, and growth rates dynamically in response to the local incident electromagnetic field would provide a remarkable route to the synthesis of complex 3D mesostructures via feedback between illumination and the structure that develops under optical excitation. We report the spontaneous development of ordered, nanoscale lamellar patterns in electrodeposited selenium–tellurium (Se–Te) alloy films grown under noncoherent, uniform illumination on unpatterned substrates in an isotropic electrolyte solution. These inorganic nanostructures exhibited phototropic growth in which lamellar stripes grew toward the incident light source, adopted an orientation parallel to the light polarization direction with a period controlled by the illumination wavelength, and showed an increased growth rate with increasing light intensity. Furthermore, the patterns responded dynamically to changes during growth in the polarization, wavelength, and angle of the incident light, enabling the template-free and pattern-free synthesis, on a variety of substrates, of woodpile, spiral, branched, or zigzag structures, along with dynamically directed growth toward a noncoherent, uniform intensity light source. Full-wave electromagnetic simulations in combination with Monte Carlo growth simulations were used to model light–matter interactions in the Se–Te films and produced a model for the morphological evolution of the lamellar structures under phototropic growth conditions. The experiments and simulations are consistent with a phototropic growth mechanism in which the optical near-field intensity profile selects and reinforces the dominant morphological mode in the emergent nanoscale patterns. PMID:24218617

  9. Phototropic growth control of nanoscale pattern formation in photoelectrodeposited Se-Te films.

    PubMed

    Sadtler, Bryce; Burgos, Stanley P; Batara, Nicolas A; Beardslee, Joseph A; Atwater, Harry A; Lewis, Nathan S

    2013-12-03

    Photoresponsive materials that adapt their morphologies, growth directions, and growth rates dynamically in response to the local incident electromagnetic field would provide a remarkable route to the synthesis of complex 3D mesostructures via feedback between illumination and the structure that develops under optical excitation. We report the spontaneous development of ordered, nanoscale lamellar patterns in electrodeposited selenium-tellurium (Se-Te) alloy films grown under noncoherent, uniform illumination on unpatterned substrates in an isotropic electrolyte solution. These inorganic nanostructures exhibited phototropic growth in which lamellar stripes grew toward the incident light source, adopted an orientation parallel to the light polarization direction with a period controlled by the illumination wavelength, and showed an increased growth rate with increasing light intensity. Furthermore, the patterns responded dynamically to changes during growth in the polarization, wavelength, and angle of the incident light, enabling the template-free and pattern-free synthesis, on a variety of substrates, of woodpile, spiral, branched, or zigzag structures, along with dynamically directed growth toward a noncoherent, uniform intensity light source. Full-wave electromagnetic simulations in combination with Monte Carlo growth simulations were used to model light-matter interactions in the Se-Te films and produced a model for the morphological evolution of the lamellar structures under phototropic growth conditions. The experiments and simulations are consistent with a phototropic growth mechanism in which the optical near-field intensity profile selects and reinforces the dominant morphological mode in the emergent nanoscale patterns.

  10. Estimation, modeling, and simulation of patterned growth in extreme environments.

    PubMed

    Strader, B; Schubert, K E; Quintana, M; Gomez, E; Curnutt, J; Boston, P

    2011-01-01

    In the search for life on Mars and other extraterrestrial bodies or in our attempts to identify biological traces in the most ancient rock record of Earth, one of the biggest problems facing us is how to recognize life or the remains of ancient life in a context very different from our planet's modern biological examples. Specific chemistries or biological properties may well be inapplicable to extraterrestrial conditions or ancient Earth environments. Thus, we need to develop an arsenal of techniques that are of broader applicability. The notion of patterning created in some fashion by biological processes and properties may provide such a generalized property of biological systems no matter what the incidentals of chemistry or environmental conditions. One approach to recognizing these kinds of patterns is to look at apparently organized arrangements created and left by life in extreme environments here on Earth, especially at various spatial scales, different geologies, and biogeochemical circumstances.

  11. Cellular and muscular growth patterns during sipunculan development.

    PubMed

    Kristof, Alen; Wollesen, Tim; Maiorova, Anastassya S; Wanninger, Andreas

    2011-05-15

    Sipuncula is a lophotrochozoan taxon with annelid affinities, albeit lacking segmentation of the adult body. Here, we present data on cell proliferation and myogenesis during development of three sipunculan species, Phascolosoma agassizii, Thysanocardia nigra, and Themiste pyroides. The first anlagen of the circular body wall muscles appear simultaneously and not subsequently as in the annelids. At the same time, the rudiments of four longitudinal retractor muscles appear. This supports the notion that four introvert retractors were part of the ancestral sipunculan bodyplan. The longitudinal muscle fibers form a pattern of densely arranged fibers around the retractor muscles, indicating that the latter evolved from modified longitudinal body wall muscles. For a short time interval, the distribution of S-phase mitotic cells shows a metameric pattern in the developing ventral nerve cord during the pelagosphera stage. This pattern disappears close to metamorphic competence. Our findings are congruent with data on sipunculan neurogenesis, as well as with recent molecular analyses that place Sipuncula within Annelida, and thus strongly support a segmental ancestry of Sipuncula.

  12. The growth pattern of the clavicle in the rat.

    PubMed Central

    Rönning, O; Kantomaa, T

    1988-01-01

    The mode of growth of the rat clavicle from 17 to 45 days of age was studied by means of vital staining (alizarin red S), histology and autoradiography (tritiated thymidine). In addition the clavicle on one side was subjected to periostomy at the age of 10 days and its length compared with that of its unoperated counterpart at the ages of 17 and 45 days. The alizarin red staining revealed that the medial end of the clavicle contributes to the length of the bone, while the lateral end appears to have mainly an articulatory function. Histologically, the medial end cartilage closely resembles the condylar cartilage of the mandible, whereas the lateral end appears to be composed of two cartilaginous structures separated by a mesenchymatous layer. Tritiated thymidine was deposited in the mesenchymal cells covering the medial end cartilage, whereas virtually no activity was observed in the mesenchyme of the lateral end cartilage. The periostomised clavicle was more slender in appearance than its control throughout the observation period. The two clavicles were of the same length at 17 days, but by 45 days the periostomised clavicle was significantly longer than the control. It is suggested that the growth of the clavicle is essentially comparable to the growth of the mandible. Length growth occurs in response to the action of the surrounding structures, while analogously to the mandibular condyle, the medial end cartilage actively translates the bone in a direction perpendicular to the articular surface, giving rise to its curved shape. Images Fig. 1 Fig. 2 Fig. 3 PMID:3248965

  13. Urban Ecology: Patterns of Population Growth and Ecological Effects

    Treesearch

    Wayne C. Zipperer; Steward T.A. Pickett

    2012-01-01

    Currently, over 50% of the world’s population lives in urban areas. By 2050, this estimate is expected to be 70%. This urban growth, however, is not uniformly distributed around the world. The majority of it will occur in developing nations and create megacities whose populations exceed at least 10 million people. Not all urban areas, however, are growing. Some are...

  14. Diffuse growth pattern affects E-cadherin expression in invasive breast cancer.

    PubMed

    Brinck, Ulrich; Jacobs, Susanne; Neuss, Michael; Tory, Kalman; Rath, Werner; Kulle, Bettina; Füzesi, Laszlo

    2004-01-01

    We investigated the correlations between growth patterns and E-cadherin expression by immunohistochemistry and the presence of mutations of exons 6-10 of the E-cadherin gene by PCR-SSCP, in 79 cases of invasive lobular and ductal breast cancer. E-cadherin expression showed a tendency to be lower in lobular than in ductal carcinomas (p=0.064). In 60% of lobular carcinomas the diffuse growth pattern and in 72% of ductal carcinomas the compact growth pattern predominated. E-cadherin expression was significantly lower in diffuse than in compact tumor area (p<0.001) and not related to carcinoma type when it was considered in tumor areas with either diffuse (p=0.278) or compact (p=0.128) growth pattern. No mutations were detected. In conclusion, loss of E-cadherin expression is related to an increase of diffuse growth pattern in both lobular and ductal types of breast cancer, and the differential proportions of growth patterns in both tumor types cause the tendency for lower E-cadherin expression in the lobular type.

  15. Growth patterns and life-history strategies in Placodontia (Diapsida: Sauropterygia)

    PubMed Central

    Klein, Nicole; Neenan, James M.; Scheyer, Torsten M.; Griebeler, Eva Maria

    2015-01-01

    Placodontia is a clade of durophagous, near shore marine reptiles from Triassic sediments of modern-day Europe, Middle East and China. Although much is known about their primary anatomy and palaeoecology, relatively little has been published regarding their life history, i.e. ageing, maturation and growth. Here, growth records derived from long bone histological data of placodont individuals are described and modelled to assess placodont growth and life-history strategies. Growth modelling methods are used to confirm traits documented in the growth record (age at onset of sexual maturity, age when asymptotic length was achieved, age at death, maximum longevity) and also to estimate undocumented traits. Based on these growth models, generalized estimates of these traits are established for each taxon. Overall differences in bone tissue types and resulting growth curves indicate different growth patterns and life-history strategies between different taxa of Placodontia. Psephoderma and Paraplacodus grew with lamellar-zonal bone tissue type and show growth patterns as seen in modern reptiles. Placodontia indet. aff. Cyamodus and some Placodontia indet. show a unique combination of fibrolamellar bone tissue regularly stratified by growth marks, a pattern absent in modern sauropsids. The bone tissue type of Placodontia indet. aff. Cyamodus and Placodontia indet. indicates a significantly increased basal metabolic rate when compared with modern reptiles. Double lines of arrested growth, non-annual rest lines in annuli, and subcycles that stratify zones suggest high dependence of placodont growth on endogenous and exogenous factors. Histological and modelled differences within taxa point to high individual developmental plasticity but sexual dimorphism in growth patterns and the presence of different taxa in the sample cannot be ruled out. PMID:26587259

  16. Spontaneous extraskeletal osteosarcoma with various histological growth patterns in the abdominal wall of an ICR mouse

    PubMed Central

    Ito, Tsuyoshi; Katoh, Yoshitaka; Shimada, Yuko; Ohnuma-Koyama, Aya; Takahashi, Naofumi; Kuwahara, Maki; Harada, Takanori

    2015-01-01

    Extraskeletal osteosarcoma is extremely rare in mice. This case report demonstrates a spontaneous murine extraskeletal osteosarcoma that exhibited various histological growth patterns in an ICR mouse. At necropsy, the tumor mass was located in the abdominal wall and was 45 × 30 × 25 mm in size. Histopathologically, the tumor showed the following four growth patterns: a solid pattern of polygonal cells embedded in an osteoid eosinophilic matrix with calcification, an irregular sheet pattern of short spindle cells accompanying some eosinophilic multinucleated cells, a fascicular pattern of spindle cells and a cystic pattern lined by short spindle cells. Immunohistochemically, most of the tumor cells were positive for vimentin, proliferating cell nuclear antigen and osterix. The multinucleated cells mentioned above were desmin positive and were regarded as regenerative striated muscles but not tumor cells. Since no clear continuity with normal bone tissues was observed, the tumor was diagnosed as an “extraskeletal osteosarcoma.” PMID:26989300

  17. Fluid flow and pattern selection in dendritic growth - Ground based in situ observation

    NASA Astrophysics Data System (ADS)

    Huang, Tao; Liu, Shan; Lu, Deyang; Zhou, Yaohe; Cheng, Gongshan

    1989-02-01

    Model experiments on fluid flow and pattern selection have been done by creating flow in liquid regions close to the growth fronts in dendritic growth of SCN-aceton dilute alloys. The kinetics and morphology of dendritic growth were measured as a function of thermal gradient, growth velocity, and flow velocity. The present paper provides the first study of convection effects on constrained dendritic and cellular growth which focuses on the tip morphology and develops a boundary layer analysis. All of the problems addressed have application to the interpretation of the experimental phenomena arising from solidification and fluid dynamics on earth and in a space laboratory.

  18. ABOVE- AND BELOWGROUND CONTROLS ON FOREST TREE GROWTH, MORTALITY AND SPATIAL PATTERN

    EPA Science Inventory

    We investigated the relative importance of above- and belowground competition in controlling growth, mortality and spatial patterns of trees in a nitrogen-limited, old-growth forest in western Oregon. To assess the effects of competition for light, we applied a spatially-explici...

  19. Effects of Atypical Patterns of Fetal Growth on Newborn (NBAS) Behavior.

    ERIC Educational Resources Information Center

    Lester, Barry M.; And Others

    1986-01-01

    Newborn infants showing anthropometric signs of atypical patterns of fetal growth were compared with infants of appropriate growth on the Neonatal Behavioral Assessment Scale and on recently developed supplementary items. The sample consisted of lower-socioeconomic-status families in San Juan, Puerto Rico, and included teenage and older mothers.…

  20. ABOVE- AND BELOWGROUND CONTROLS ON FOREST TREE GROWTH, MORTALITY AND SPATIAL PATTERN

    EPA Science Inventory

    We investigated the relative importance of above- and belowground competition in controlling growth, mortality and spatial patterns of trees in a nitrogen-limited, old-growth forest in western Oregon. To assess the effects of competition for light, we applied a spatially-explici...

  1. Effects of Atypical Patterns of Fetal Growth on Newborn (NBAS) Behavior.

    ERIC Educational Resources Information Center

    Lester, Barry M.; And Others

    1986-01-01

    Newborn infants showing anthropometric signs of atypical patterns of fetal growth were compared with infants of appropriate growth on the Neonatal Behavioral Assessment Scale and on recently developed supplementary items. The sample consisted of lower-socioeconomic-status families in San Juan, Puerto Rico, and included teenage and older mothers.…

  2. AliBaba: PubMed as a graph.

    PubMed

    Plake, Conrad; Schiemann, Torsten; Pankalla, Marcus; Hakenberg, Jörg; Leser, Ulf

    2006-10-01

    The biomedical literature contains a wealth of information on associations between many different types of objects, such as protein-protein interactions, gene-disease associations and subcellular locations of proteins. When searching such information using conventional search engines, e.g. PubMed, users see the data only one-abstract at a time and 'hidden' in natural language text. AliBaba is an interactive tool for graphical summarization of search results. It parses the set of abstracts that fit a PubMed query and presents extracted information on biomedical objects and their relationships as a graphical network. AliBaba extracts associations between cells, diseases, drugs, proteins, species and tissues. Several filter options allow for a more focused search. Thus, researchers can grasp complex networks described in various articles at a glance. http://alibaba.informatik.hu-berlin.de/

  3. Studying PubMed usages in the field for complex problem solving: Implications for tool design.

    PubMed

    Mirel, Barbara; Song, Jean; Tonks, Jennifer Steiner; Meng, Fan; Xuan, Weijian; Ameziane, Rafiqa

    2013-05-01

    Many recent studies on MEDLINE-based information seeking have shed light on scientists' behaviors and associated tool innovations that may improve efficiency and effectiveness. Few if any studies, however, examine scientists' problem-solving uses of PubMed in actual contexts of work and corresponding needs for better tool support. Addressing this gap, we conducted a field study of novice scientists (14 upper level undergraduate majors in molecular biology) as they engaged in a problem solving activity with PubMed in a laboratory setting. Findings reveal many common stages and patterns of information seeking across users as well as variations, especially variations in cognitive search styles. Based on findings, we suggest tool improvements that both confirm and qualify many results found in other recent studies. Our findings highlight the need to use results from context-rich studies to inform decisions in tool design about when to offer improved features to users.

  4. Studying PubMed usages in the field for complex problem solving: Implications for tool design

    PubMed Central

    Song, Jean; Tonks, Jennifer Steiner; Meng, Fan; Xuan, Weijian; Ameziane, Rafiqa

    2012-01-01

    Many recent studies on MEDLINE-based information seeking have shed light on scientists’ behaviors and associated tool innovations that may improve efficiency and effectiveness. Few if any studies, however, examine scientists’ problem-solving uses of PubMed in actual contexts of work and corresponding needs for better tool support. Addressing this gap, we conducted a field study of novice scientists (14 upper level undergraduate majors in molecular biology) as they engaged in a problem solving activity with PubMed in a laboratory setting. Findings reveal many common stages and patterns of information seeking across users as well as variations, especially variations in cognitive search styles. Based on findings, we suggest tool improvements that both confirm and qualify many results found in other recent studies. Our findings highlight the need to use results from context-rich studies to inform decisions in tool design about when to offer improved features to users. PMID:24376375

  5. Infants born to narcotic dependent mothers: physical growth patterns in the first 12 months of life.

    PubMed

    Vance, J C; Chant, D C; Tudehope, D I; Gray, P H; Hayes, A J

    1997-12-01

    To describe the physical growth patterns of infants born to narcotic dependent mothers (INDM) over a 12 months period and, if possible, to relate the growth to drug taking patterns during pregnancy. The growth of a cohort of 43 INDM was measured during the first 12 months of life. Weight and length measurements were compared with percentile charts and converted to Z scores. Questionnaire data about drug taking practices, demographic variables and the neonatal period (including withdrawal scores) were obtained. Twenty-four (55.8%) of INDM had evidence of neonatal drug withdrawal requiring treatment with phenobarbitone. At birth, Z scores for weight and length indicated relative intrauterine growth retardation. By 12 months, there had been some catch up growth, but Z scores for weight and length were still below zero. Persistent weight retardation at 12 months was correlated with methadone dosage during pregnancy, but not the need for phenobarbitone therapy. The growth patterns of INDM in the first 12 months of life indicated that at birth there was evidence of intrauterine growth retardation, but by 12 months the growth was little different from the rest of the community. There appears to be some influence of narcotic agents taken while pregnant on subsequent growth of INDM.

  6. Positional specification in the segmental growth pattern of an early arthropod

    PubMed Central

    Fusco, Giuseppe; Hong, Paul S.; Hughes, Nigel C.

    2014-01-01

    In many arthropods, there is a change in relative segment size during post-embryonic development, but how segment differential growth is produced is little known. A new dataset of the highest quality specimens of the 429 Myr old trilobite Aulacopleura koninckii provides an unparalleled opportunity to investigate segment growth dynamics and its control in an early arthropod. Morphometric analysis across nine post-embryonic stages revealed a growth gradient in the trunk of A. koninckii. We contrastively tested different growth models referable to two distinct hypotheses of growth control for the developing trunk: (i) a segment-specific control, with individual segments having differential autonomous growth progression, and (ii) a regional control, with segment growth depending on their relative position along the main axis. We show that the trunk growth pattern of A. koninckii was consistent with a regional growth control producing a continuous growth gradient that was stable across all developmental stages investigated. The specific posterior-to-anterior decaying shape of the growth gradient suggests it deriving from the linear transduction of a graded signal, similar to those commonly provided by morphogens. A growth control depending on a form of positional specification, possibly realized through the linear interpretation of a graded signal, may represent the primitive condition for arthropod differential growth along the main body axis, from which the diverse and generally more complex forms of growth control in subsequent arthropods have evolved. PMID:24573851

  7. Complex event extraction at PubMed scale

    PubMed Central

    Björne, Jari; Ginter, Filip; Pyysalo, Sampo; Tsujii, Jun'ichi; Salakoski, Tapio

    2010-01-01

    Motivation: There has recently been a notable shift in biomedical information extraction (IE) from relation models toward the more expressive event model, facilitated by the maturation of basic tools for biomedical text analysis and the availability of manually annotated resources. The event model allows detailed representation of complex natural language statements and can support a number of advanced text mining applications ranging from semantic search to pathway extraction. A recent collaborative evaluation demonstrated the potential of event extraction systems, yet there have so far been no studies of the generalization ability of the systems nor the feasibility of large-scale extraction. Results: This study considers event-based IE at PubMed scale. We introduce a system combining publicly available, state-of-the-art methods for domain parsing, named entity recognition and event extraction, and test the system on a representative 1% sample of all PubMed citations. We present the first evaluation of the generalization performance of event extraction systems to this scale and show that despite its computational complexity, event extraction from the entire PubMed is feasible. We further illustrate the value of the extraction approach through a number of analyses of the extracted information. Availability: The event detection system and extracted data are open source licensed and available at http://bionlp.utu.fi/. Contact: jari.bjorne@utu.fi PMID:20529932

  8. Tree growth and competition in an old-growth Picea abies forest of boreal Sweden: influence of tree spatial patterning

    USGS Publications Warehouse

    Fraver, Shawn; D'Amato, Anthony W.; Bradford, John B.; Jonsson, Bengt Gunnar; Jönsson, Mari; Esseen, Per-Anders

    2013-01-01

    Question: What factors best characterize tree competitive environments in this structurally diverse old-growth forest, and do these factors vary spatially within and among stands? Location: Old-growth Picea abies forest of boreal Sweden. Methods: Using long-term, mapped permanent plot data augmented with dendrochronological analyses, we evaluated the effect of neighbourhood competition on focal tree growth by means of standard competition indices, each modified to include various metrics of trees size, neighbour mortality weighting (for neighbours that died during the inventory period), and within-neighbourhood tree clustering. Candidate models were evaluated using mixed-model linear regression analyses, with mean basal area increment as the response variable. We then analysed stand-level spatial patterns of competition indices and growth rates (via kriging) to determine if the relationship between these patterns could further elucidate factors influencing tree growth. Results: Inter-tree competition clearly affected growth rates, with crown volume being the size metric most strongly influencing the neighbourhood competitive environment. Including neighbour tree mortality weightings in models only slightly improved descriptions of competitive interactions. Although the within-neighbourhood clustering index did not improve model predictions, competition intensity was influenced by the underlying stand-level tree spatial arrangement: stand-level clustering locally intensified competition and reduced tree growth, whereas in the absence of such clustering, inter-tree competition played a lesser role in constraining tree growth. Conclusions: Our findings demonstrate that competition continues to influence forest processes and structures in an old-growth system that has not experienced major disturbances for at least two centuries. The finding that the underlying tree spatial pattern influenced the competitive environment suggests caution in interpreting traditional tree

  9. Non-linear pattern formation in bone growth and architecture.

    PubMed

    Salmon, Phil

    2014-01-01

    The three-dimensional morphology of bone arises through adaptation to its required engineering performance. Genetically and adaptively bone travels along a complex spatiotemporal trajectory to acquire optimal architecture. On a cellular, micro-anatomical scale, what mechanisms coordinate the activity of osteoblasts and osteoclasts to produce complex and efficient bone architectures? One mechanism is examined here - chaotic non-linear pattern formation (NPF) - which underlies in a unifying way natural structures as disparate as trabecular bone, swarms of birds flying, island formation, fluid turbulence, and others. At the heart of NPF is the fact that simple rules operating between interacting elements, and Turing-like interaction between global and local signals, lead to complex and structured patterns. The study of "group intelligence" exhibited by swarming birds or shoaling fish has led to an embodiment of NPF called "particle swarm optimization" (PSO). This theoretical model could be applicable to the behavior of osteoblasts, osteoclasts, and osteocytes, seeing them operating "socially" in response simultaneously to both global and local signals (endocrine, cytokine, mechanical), resulting in their clustered activity at formation and resorption sites. This represents problem-solving by social intelligence, and could potentially add further realism to in silico computer simulation of bone modeling. What insights has NPF provided to bone biology? One example concerns the genetic disorder juvenile Pagets disease or idiopathic hyperphosphatasia, where the anomalous parallel trabecular architecture characteristic of this pathology is consistent with an NPF paradigm by analogy with known experimental NPF systems. Here, coupling or "feedback" between osteoblasts and osteoclasts is the critical element. This NPF paradigm implies a profound link between bone regulation and its architecture: in bone the architecture is the regulation. The former is the emergent

  10. Non-Linear Pattern Formation in Bone Growth and Architecture

    PubMed Central

    Salmon, Phil

    2014-01-01

    The three-dimensional morphology of bone arises through adaptation to its required engineering performance. Genetically and adaptively bone travels along a complex spatiotemporal trajectory to acquire optimal architecture. On a cellular, micro-anatomical scale, what mechanisms coordinate the activity of osteoblasts and osteoclasts to produce complex and efficient bone architectures? One mechanism is examined here – chaotic non-linear pattern formation (NPF) – which underlies in a unifying way natural structures as disparate as trabecular bone, swarms of birds flying, island formation, fluid turbulence, and others. At the heart of NPF is the fact that simple rules operating between interacting elements, and Turing-like interaction between global and local signals, lead to complex and structured patterns. The study of “group intelligence” exhibited by swarming birds or shoaling fish has led to an embodiment of NPF called “particle swarm optimization” (PSO). This theoretical model could be applicable to the behavior of osteoblasts, osteoclasts, and osteocytes, seeing them operating “socially” in response simultaneously to both global and local signals (endocrine, cytokine, mechanical), resulting in their clustered activity at formation and resorption sites. This represents problem-solving by social intelligence, and could potentially add further realism to in silico computer simulation of bone modeling. What insights has NPF provided to bone biology? One example concerns the genetic disorder juvenile Pagets disease or idiopathic hyperphosphatasia, where the anomalous parallel trabecular architecture characteristic of this pathology is consistent with an NPF paradigm by analogy with known experimental NPF systems. Here, coupling or “feedback” between osteoblasts and osteoclasts is the critical element. This NPF paradigm implies a profound link between bone regulation and its architecture: in bone the architecture is the regulation. The former is the

  11. [Spatiotemporal pattern and its driving forces of urban growth in Shenyang City].

    PubMed

    Wu, Xiao-Qing; Hu, Yuan-Man; He, Hong-Shi; Bu, Ren-Cang; Xi, Feng-Ming

    2007-10-01

    By using time series Landsat TM satellite images and adopting GIS spatial analysis and landscape pattern analysis methods, this paper studied the spatiotemporal diversity of urban growth and the evolution of urban landscape pattern in Shenyang, and examined their driving forces. The results showed that in 1988-2004, the urban area in Shenyang increased persistently, and the growth intensity enhanced consistently, with the peaks occured in 2000-2004. The spatial differentiation of urban growth in the City was also distinct, with the southwest direction as the leading orientation, and the urban edges and different level economic development zones as the main growth areas. The urban landscape pattern became more and more complex, and the compactness index of urban development decreased. The evolution of urban landscape pattern was related to the characteristics of urban growth, which also showed spatiotemporal diversity. The urban growth and urban landscape pattern evolution in Shenyang were mainly attributed to the development of industrialization and the construction of different level economic development zones, the proper policies of local governments and the urban planning, as well as the development of traffic infrastructure.

  12. Optimization of GaN MOVPE growth on patterned Si substrates using spectroscopic in situ reflectance

    NASA Astrophysics Data System (ADS)

    Strittmatter, A.; Reißmann, L.; Trepk, T.; Pohl, U. W.; Bimberg, D.; Zettler, J.-T.

    2004-12-01

    In real-time monitoring of III-Nitride growth on patterned and masked substrates by spectroscopic reflectance, a characteristic interference pattern generated by the superposition of wave-fronts reflected at different μm-sized structures at the sample surface is measured. Up to now this time- and wavelength-dependent pattern was used only for empirical fingerprint-evaluation of III-Nitride growth processes which employ patterning or masking for bulk defect reduction. In this paper, we report on the analysis of real-time spectroscopic reflectance data measured in the range 1.65-4.5 eV during the epitaxial growth of GaN layers on structured Si(1 1 1) substrates. The successful implementation of a two-dimensional interference model into conventional thin-film analysis algorithms enables the quantitative analysis of characteristic vertical and lateral growth rates and overgrowth mechanisms involved. The new method is applied to optimize III-Nitride growth processes on patterned silicon substrates used for subsequent III-Nitride device growth.

  13. Recent patterns of crop yield growth and stagnation.

    PubMed

    Ray, Deepak K; Ramankutty, Navin; Mueller, Nathaniel D; West, Paul C; Foley, Jonathan A

    2012-01-01

    In the coming decades, continued population growth, rising meat and dairy consumption and expanding biofuel use will dramatically increase the pressure on global agriculture. Even as we face these future burdens, there have been scattered reports of yield stagnation in the world's major cereal crops, including maize, rice and wheat. Here we study data from ∼2.5 million census observations across the globe extending over the period 1961-2008. We examined the trends in crop yields for four key global crops: maize, rice, wheat and soybeans. Although yields continue to increase in many areas, we find that across 24-39% of maize-, rice-, wheat- and soybean-growing areas, yields either never improve, stagnate or collapse. This result underscores the challenge of meeting increasing global agricultural demands. New investments in underperforming regions, as well as strategies to continue increasing yields in the high-performing areas, are required.

  14. The reassertion of latent growth patterns following orthodontic treatment.

    PubMed

    Lenz, B E; Harris, E F

    2001-01-01

    This study reports on evaluation of the occlusion in 16 young adults who had been treated orthodontically an average of 10 years previously. Cases were from among dental students who, we assume, have high dental "IQs" and greater than average concern for stability of their orthodontic correction. Relapse of the orthodontic correction was substantial; both dental and skeletal dimensions relapsed--returned toward pretreatment conditions--to statistically and clinically obvious extents. Relapse is greater here than some other studies because of our longer recall period. Results focus attention on the importance of prolonged posttreatment retention and greater awareness on the patient's part of the role of posttreatment facial growth on relapse from adolescence into adulthood.

  15. Correlations between polyamine ratios and growth patterns in seedling roots

    NASA Technical Reports Server (NTRS)

    Shen, H. J.; Galston, A. W.

    1985-01-01

    The levels of putrescine, cadaverine, spermidine and spermine were determined in seedling roots of pea, tomato, millet and corn, as well as in corn coleoptiles and pea internodes. In all roots, putrescine content increased as elongation progressed, and the putrescine/spermine ratio closely paralleled the sigmoid growth curve up until the time of lateral root initiation. Spermidine and spermine were most abundant near the apices and declined progressively with increasing age of the cells. In the zone of differentiation of root hairs in pea roots, putrescine rose progressively with increasing age, while cadaverine declined. In both pea internodes and corn coleoptiles, the putrescine/spermidine ratio rises with increasing age and elongation. Thus, a block in the conversion of the diamine putrescine to the triamine spermidine may be an important step in the change from cell division to cell elongation.

  16. Correlations between polyamine ratios and growth patterns in seedling roots

    NASA Technical Reports Server (NTRS)

    Shen, H. J.; Galston, A. W.

    1985-01-01

    The levels of putrescine, cadaverine, spermidine and spermine were determined in seedling roots of pea, tomato, millet and corn, as well as in corn coleoptiles and pea internodes. In all roots, putrescine content increased as elongation progressed, and the putrescine/spermine ratio closely paralleled the sigmoid growth curve up until the time of lateral root initiation. Spermidine and spermine were most abundant near the apices and declined progressively with increasing age of the cells. In the zone of differentiation of root hairs in pea roots, putrescine rose progressively with increasing age, while cadaverine declined. In both pea internodes and corn coleoptiles, the putrescine/spermidine ratio rises with increasing age and elongation. Thus, a block in the conversion of the diamine putrescine to the triamine spermidine may be an important step in the change from cell division to cell elongation.

  17. Bevacizumab for Patients with Recurrent Gliomas Presenting with a Gliomatosis Cerebri Growth Pattern.

    PubMed

    Burger, Michael C; Mildenberger, Iris C; Wagner, Marlies; Mittelbronn, Michel; Steinbach, Joachim P; Bähr, Oliver

    2017-03-29

    Bevacizumab has been shown to improve progression-free survival and neurologic function, but failed to improve overall survival in newly diagnosed glioblastoma and at first recurrence. Nonetheless, bevacizumab is widely used in patients with recurrent glioma. However, its use in patients with gliomas showing a gliomatosis cerebri growth pattern is contentious. Due to the marked diffuse and infiltrative growth with less angiogenic tumor growth, it may appear questionable whether bevacizumab can have a therapeutic effect in those patients. However, the development of nodular, necrotic, and/or contrast-enhancing lesions in patients with a gliomatosis cerebri growth pattern is not uncommon and may indicate focal neo-angiogenesis. Therefore, control of growth of these lesions as well as control of edema and reduction of steroid use may be regarded as rationales for the use of bevacizumab in these patients. In this retrospective patient series, we report on 17 patients with primary brain tumors displaying a gliomatosis cerebri growth pattern (including seven glioblastomas, two anaplastic astrocytomas, one anaplastic oligodendroglioma, and seven diffuse astrocytomas). Patients have been treated with bevacizumab alone or in combination with lomustine or irinotecan. Seventeen matched patients treated with bevacizumab for gliomas with a classical growth pattern served as a control cohort. Response rate, progression-free survival, and overall survival were similar in both groups. Based on these results, anti-angiogenic therapy with bevacizumab should also be considered in patients suffering from gliomas with a mainly infiltrative phenotype.

  18. Detecting Associations between Early-Life DDT Exposures and Childhood Growth Patterns: A Novel Statistical Approach.

    PubMed

    Heggeseth, Brianna; Harley, Kim; Warner, Marcella; Jewell, Nicholas; Eskenazi, Brenda

    2015-01-01

    It has been hypothesized that environmental exposures at key development periods such as in utero play a role in childhood growth and obesity. To investigate whether in utero exposure to endocrine-disrupting chemicals, dichlorodiphenyltrichloroethane (DDT) and its metabolite, dichlorodiphenyldichloroethane (DDE), is associated with childhood physical growth, we took a novel statistical approach to analyze data from the CHAMACOS cohort study. To model heterogeneity in the growth patterns, we used a finite mixture model in combination with a data transformation to characterize body mass index (BMI) with four groups and estimated the association between exposure and group membership. In boys, higher maternal concentrations of DDT and DDE during pregnancy are associated with a BMI growth pattern that is stable until about age five followed by increased growth through age nine. In contrast, higher maternal DDT exposure during pregnancy is associated with a flat, relatively stable growth pattern in girls. This study suggests that in utero exposure to DDT and DDE may be associated with childhood BMI growth patterns, not just BMI level, and both the magnitude of exposure and sex may impact the relationship.

  19. Differential effects of NGF and NT-3 on embryonic trigeminal axon growth patterns.

    PubMed

    Ulupinar, E; Jacquin, M F; Erzurumlu, R S

    2000-09-18

    We examined the effects of neurotrophins nerve growth factor (NGF) and neurotrophin-3 (NT-3) on trigeminal axon growth patterns. Embryonic (E13-15) wholemount explants of the rat trigeminal pathway including the whisker pads, trigeminal ganglia, and brainstem were cultured in serum-free medium (SFM) or SFM supplemented with NGF or NT-3 for 3 days. Trigeminal axon growth patterns were analyzed with the use of lipophilic tracer DiI. In wholemount cultures grown in SFM, trigeminal axon projections, growth patterns, and differentiation of peripheral and central targets are similar to in vivo conditions. We show that in the presence of NGF, central trigeminal axons leave the tract and grow into the surrounding brainstem regions in the elongation phase without any branching. On the other hand, NT-3 promotes precocious development of short axon collaterals endowed with focal arbors along the sides of the central trigeminal tract. These neurotrophins also affect trigeminal axon growth within the whisker pad. Additionally, we cultured dissociated trigeminal ganglion cells in the presence of NGF, NT-3, or NGF+NT-3. The number of trigeminal ganglion cells, their size distribution under each condition were charted, and axon growth was analyzed following immunohistochemical labeling with TrkA and parvalbumin antibodies. In these cultures too, NGF led to axon elongation and NT-3 to axon arborization. Our in vitro analyses suggest that aside from their survival promoting effects, NGF and NT-3 can differentially influence axon growth patterns of embryonic trigeminal neurons.

  20. Target Turing patterns and growth dynamics in the chlorine dioxide-iodine-malonic acid reaction.

    PubMed

    Preska Steinberg, Asher; Epstein, Irving R; Dolnik, Milos

    2014-04-03

    We study the growth dynamics of Turing patterns in the chlorine dioxide-iodine-malonic acid reaction-diffusion system in response to perturbations with visible light. We describe several mechanisms by which Turing patterns reappear after they are suppressed by illumination with a disc-shaped geometry. We observe that under specific conditions the patterns reorganize from a random configuration of spots and stripes to a set of ordered, concentric rings, which we refer to as target Turing patterns. These patterns closely resemble the unit cells of the Turing hexagonal superlattices known as black eye patterns. However, these target Turing patterns are not part of a larger superlattice structure, and they usually have a larger number of concentric rings. Numerical simulations support the experimental findings.

  1. Predictive spatial modeling of narcotic crop growth patterns

    USGS Publications Warehouse

    Waltz, Frederick A.; Moore, D.G.

    1986-01-01

    Spatial models for predicting the geographic distribution of marijuana crops have been developed and are being evaluated for use in law enforcement programs. The models are based on growing condition preferences and on psychological inferences regarding grower behavior. Experiences of local law officials were used to derive the initial model, which was updated and improved as data from crop finds were archived and statistically analyzed. The predictive models are changed as crop locations are moved in response to the pressures of law enforcement. The models use spatial data in a raster geographic information system. The spatial data are derived from the U.S. Geological Survey's US GeoData, standard 7.5-minute topographic quadrangle maps, interpretations of aerial photographs, and thematic maps. Updating of cultural patterns, canopy closure, and other dynamic features is conducted through interpretation of aerial photographs registered to the 7.5-minute quadrangle base. The model is used to numerically weight various data layers that have been processed using spread functions, edge definition, and categorization. The building of the spatial data base, model development, model application, product generation, and use are collectively referred to as the Area Reduction Program (ARP). The goal of ARP is to provide law enforcement officials with tactical maps that show the most likely locations for narcotic crops.

  2. [Seasonal patterns of breast tumor growth in Far North residents].

    PubMed

    Borisenkov, M F; Bazhenov, S M

    2005-01-01

    Earlier, we established a relationship between sex hormone receptor concentration in tumor and 5-year survival, on the one hand, and seasonality, on the other. The parameters showed a distinct 6-month cycle. That pointed to certain environmental factors which could synchronize hormone-dependent tumor process in the breast of women living in the North. The present study is concerned with a relationship of 6-month rhythm of tumor growth and latitude of residence. Said rhythm was reliably identified as a parameter of 5-year survival in the Far North (68 deg. northern latitude, p < 0.001). Maximum values of 5-year survival were registered in those diagnosed with cancer in winter or summer, while those diagnosed in spring or fall had unfavorable prognosis. Northern magnetic storms recur at 6-month intervals and most frequently in spring and fall. Electromagnetic radiation is known to suppress melatonin production and, that might have stimulated tumor process. Therefore, it is most likely that solar electromagnetic radiation might synchronize hormone-dependent tumor process in women resident in the North.

  3. Growth patterns and their implications for preterm infants in a culture of rapid modernization.

    PubMed

    Ahn, Youngmee; Sohn, Min; Jun, Yonghoon; Lee, Sangmi

    2013-09-01

    This prospective longitudinal study explored the growth patterns of preterm infants and the implications of rearing them in an advancing culture. The study measured the weight, length, and head circumference of 343 Korean preterm infants over 12 months corrected age. Data were analyzed using a generalized estimation equation for growth patterns of preterm infants by the degree of prematurity (mild, moderate, or severe). Results showed that the early 'catch-up phenomenon', accelerated growth rate, occurred around 11 months corrected age, although the mild preterm group weighed less, was shorter, and had a smaller head circumference than the moderate and severe preterm groups. This may reflect the Asian culture's preference for big babies and draws special attention to the influence of cultural values and childrearing practices in the growth of preterm infants. Pediatric nurses should be alert to accelerated growth in preterm infants in societies in cultural transition.

  4. Secondary Growth and Carbohydrate Storage Patterns Differ between Sexes in Juniperus thurifera

    PubMed Central

    DeSoto, Lucía; Olano, José M.; Rozas, Vicente

    2016-01-01

    Differences in reproductive costs between male and female plants have been shown to foster sex-related variability in growth and C-storage patterns. The extent to which differential secondary growth in dioecious trees is associated with changes in stem carbohydrate storage patterns, however, has not been fully assessed. We explored the long-term radial growth and the seasonal variation of non-structural carbohydrate (NSC) content in sapwood of 40 males and 40 females Juniperus thurifera trees at two sites. NSC content was analyzed bimonthly for 1 year, and tree-ring width was measured for the 1931–2010 period. Sex-related differences in secondary growth and carbohydrate storage were site-dependent. Under less restrictive environmental conditions females grew more and stored more non-soluble sugars than males. Our results reinforce that sex-related differences in growth and resource storage may be a consequence of local adaptation to environmental conditions. Seasonal variation in soluble sugars concentration was opposite to cambial activity, with minima seen during periods of maximal secondary growth, and did not differ between the sexes or sites. Trees with higher stem NSC levels at critical periods showed higher radial growth, suggesting a common mechanism irrespective of site or sex. Sex-related patterns of secondary growth were linked to differences in non-soluble sugars content indicating sex-specific strategies of long-term performance. PMID:27303418

  5. Retrieval of diagnostic and treatment studies for clinical use through PubMed and PubMed's Clinical Queries filters

    PubMed Central

    Haynes, R Brian; Wilczynski, Nancy L; McKibbon, K Ann; Walter, Stephen D

    2011-01-01

    Objective Clinical Queries filters were developed to improve the retrieval of high-quality studies in searches on clinical matters. The study objective was to determine the yield of relevant citations and physician satisfaction while searching for diagnostic and treatment studies using the Clinical Queries page of PubMed compared with searching PubMed without these filters. Materials and methods Forty practicing physicians, presented with standardized treatment and diagnosis questions and one question of their choosing, entered search terms which were processed in a random, blinded fashion through PubMed alone and PubMed Clinical Queries. Participants rated search retrievals for applicability to the question at hand and satisfaction. Results For treatment, the primary outcome of retrieval of relevant articles was not significantly different between the groups, but a higher proportion of articles from the Clinical Queries searches met methodologic criteria (p=0.049), and more articles were published in core internal medicine journals (p=0.056). For diagnosis, the filtered results returned more relevant articles (p=0.031) and fewer irrelevant articles (overall retrieval less, p=0.023); participants needed to screen fewer articles before arriving at the first relevant citation (p<0.05). Relevance was also influenced by content terms used by participants in searching. Participants varied greatly in their search performance. Discussion Clinical Queries filtered searches returned more high-quality studies, though the retrieval of relevant articles was only statistically different between the groups for diagnosis questions. Conclusion Retrieving clinically important research studies from Medline is a challenging task for physicians. Methodological search filters can improve search retrieval. PMID:21680559

  6. Retrieval of diagnostic and treatment studies for clinical use through PubMed and PubMed's Clinical Queries filters.

    PubMed

    Lokker, Cynthia; Haynes, R Brian; Wilczynski, Nancy L; McKibbon, K Ann; Walter, Stephen D

    2011-01-01

    Clinical Queries filters were developed to improve the retrieval of high-quality studies in searches on clinical matters. The study objective was to determine the yield of relevant citations and physician satisfaction while searching for diagnostic and treatment studies using the Clinical Queries page of PubMed compared with searching PubMed without these filters. Forty practicing physicians, presented with standardized treatment and diagnosis questions and one question of their choosing, entered search terms which were processed in a random, blinded fashion through PubMed alone and PubMed Clinical Queries. Participants rated search retrievals for applicability to the question at hand and satisfaction. For treatment, the primary outcome of retrieval of relevant articles was not significantly different between the groups, but a higher proportion of articles from the Clinical Queries searches met methodologic criteria (p=0.049), and more articles were published in core internal medicine journals (p=0.056). For diagnosis, the filtered results returned more relevant articles (p=0.031) and fewer irrelevant articles (overall retrieval less, p=0.023); participants needed to screen fewer articles before arriving at the first relevant citation (p<0.05). Relevance was also influenced by content terms used by participants in searching. Participants varied greatly in their search performance. Clinical Queries filtered searches returned more high-quality studies, though the retrieval of relevant articles was only statistically different between the groups for diagnosis questions. Retrieving clinically important research studies from Medline is a challenging task for physicians. Methodological search filters can improve search retrieval.

  7. Simple growth patterns can create complex trajectories for the ontogeny of constitutive chemical defences in seaweeds.

    PubMed

    Paul, Nicholas A; Svensson, Carl Johan; de Nys, Rocky; Steinberg, Peter D

    2014-01-01

    All of the theory and most of the data on the ecology and evolution of chemical defences derive from terrestrial plants, which have considerable capacity for internal movement of resources. In contrast, most macroalgae--seaweeds--have no or very limited capacity for resource translocation, meaning that trade-offs between growth and defence, for example, should be localised rather than systemic. This may change the predictions of chemical defence theories for seaweeds. We developed a model that mimicked the simple growth pattern of the red seaweed Asparagopsis armata which is composed of repeating clusters of somatic cells and cells which contain deterrent secondary chemicals (gland cells). To do this we created a distinct growth curve for the somatic cells and another for the gland cells using empirical data. The somatic growth function was linked to the growth function for defence via differential equations modelling, which effectively generated a trade-off between growth and defence as these neighbouring cells develop. By treating growth and defence as separate functions we were also able to model a trade-off in growth of 2-3% under most circumstances. However, we found contrasting evidence for this trade-off in the empirical relationships between growth and defence, depending on the light level under which the alga was cultured. After developing a model that incorporated both branching and cell division rates, we formally demonstrated that positive correlations between growth and defence are predicted in many circumstances and also that allocation costs, if they exist, will be constrained by the intrinsic growth patterns of the seaweed. Growth patterns could therefore explain contrasting evidence for cost of constitutive chemical defence in many studies, highlighting the need to consider the fundamental biology and ontogeny of organisms when assessing the allocation theories for defence.

  8. Growth patterns of an intertidal gastropod as revealed by oxygen isotope analysis

    NASA Astrophysics Data System (ADS)

    Bean, J. R.; Hill, T. M.; Guerra, C.

    2007-12-01

    The size and morphology of mollusk shells are affected by environmental conditions. As a result, it is difficult to assess growth rate, population age structure, shell morphologies associated with ontogenetic stages, and to compare life history patterns across various environments. Oxygen isotope analysis is a useful tool for estimating minimum ages and growth rates of calcium carbonate secreting organisms. Calcite shell material from members of two northern California populations of the intertidal muricid gastropod Acanthinucella spirata was sampled for isotopic analysis. Individual shells were sampled from apex to margin, thus providing a sequential record of juvenile and adult growth. A. spirata were collected from a sheltered habitat in Tomales Bay and from an exposed reef in Bolinas. Abiotic factors, such as temperature, wave exposure, and substrate consistency, and biotic composition differ significantly between these sites, possibly resulting in local adaptations and variation in life history and growth patterns. Shell morphology of A. spirata changes with age as internal shell margin thickenings of denticle rows associated with external growth bands are irregularly accreted. It is not known when, either seasonally and/or ontogentically, these thickenings and bands form or whether inter or intra-populational variation exists. Preliminary results demonstrate the seasonal oxygen isotopic variability present at the two coastal sites, indicating 5-6 degC changes from winter to summertime temperatures; these data are consistent with local intertidal temperature records. Analysis of the seasonal patterns indicate that: 1) differences in growth rate and seasonal growth patterns at different ontogenetic stages within populations, and 2) differences in growth patterns and possibly age structure between the two A. spirata populations. These findings indicate that isotopic analyses, in addition to field observations and morphological measurements, are necessary to

  9. A Retrospective Analysis of the Growth Pattern in Patients with Salt-wasting 21-Hydroxylase Deficiency

    PubMed Central

    Kawano, Atsuko; Kohno, Hitoshi; Miyako, Kenichi

    2014-01-01

    Abstract The objective of this study was to investigate the growth pattern of children with the salt-wasting form of congenital adrenal hyperplasia caused by 21-hydroxylase deficiency (21-OHD). We reviewed the medical records of 13 patients in whom salt-wasting 21-OHD was diagnosed during the first 2 mo of life at our hospital from 1980 through 2008. Six reached adult height. Growth patterns, bone age, biochemical data, and the hydrocortisone dose at each growth stage were analyzed retrospectively. The mean adult height was 155.1 ± 6.5 cm (mean ± SD) in females and 158.1 ± 7.1 cm in males. Although length at birth was normal or longer than the national mean in almost all patients, the mean height SD score of both boys and girls decreased to below 0 SD during infancy. Subsequently, both boys and girls transiently showed growth acceleration and reached their peak growth velocity at 3–10 yr of age. In conclusion, in addition to suppression of growth during infancy, there was inappropriate growth acceleration during childhood. Especially from 3 mo to 3 yr of age, decreasing the hydrocortisone dose in patients who exhibit slower growth may lead to satisfactory height outcomes. Also, strict adjustment of the hydrocortisone dose to avoid accelerated growth from childhood to adolescence might improve adult height outcomes of patients with 21-OHD. PMID:24790384

  10. Selective pattern of cancer cell accumulation and growth using UV modulating printing of hydrogels.

    PubMed

    Yang, Wenguang; Yu, Haibo; Wei, Fanan; Li, Gongxin; Wang, Yuechao; Liu, Lianqing

    2015-12-01

    Fabrication of extracellular microenvironment for cancer cell growth in vitro is an indispensable technique to precisely control the cell spatial arrangement and proliferation for cell-behavior research. Current micropatterning methods usually require relatively complicated operations, which makes it difficult to investigate the effects of different cell growth patterns. This manuscript proposes a DMD-based projection technique to quickly pattern a poly(ethylene) glycol diacrylate (PEGDA)-based hydrogel on a common glass substrate. Using this method, we can effectively control the growth patterns of cells. Compared with these traditional methods which employ digital dynamic mask, polymerization of PEGDA solution can be used to create arbitrary shaped microstructures with high efficiency, flexibility and repeatability. The duration of UV exposure is less than 10 s through controlling the projected illumination pattern. The ability of patterned PEGDA-coated film to hinder cell adhesion makes it possible to control area over which cells attach. In our experiments, we take advantage of the blank area to pattern cells, which allows cells to grow in various pre-designed shapes and sizes. And the patterning cells have a high viability after culturing for several days. Interestingly, we found that the restricted space could stiffen and strengthen the cells. These results indicate that cells and extracellular microenvironment can influence each other.

  11. Growth patterns in children with intrauterine growth retardation and their correlation to neurocognitive development.

    PubMed

    Fattal-Valevski, Aviva; Toledano-Alhadef, Hagit; Leitner, Yael; Geva, Ronny; Eshel, Rina; Harel, Shaul

    2009-07-01

    The relationship between somatic growth and neurocognitive outcome was studied in a cohort of 136 children with intrauterine growth retardation. The children were followed up from birth to 9 to 10 years of age by annual measurements of growth parameters, neurodevelopmental evaluations, and IQ. The rate of catch-up for height between 1 and 2 years of age was significantly higher than the catch-up for weight (P < .001). The cognitive outcome at 9 to 10 years correlated with head circumference at all ages. The neurodevelopmental outcome at 9 to 10 years correlated with weight at all ages. Correlation with head circumference was more significant with IQ, while with weight it was stronger with the neurodevelopmental score. Height at 1 year was a significant predictor for IQ and neurodevelopmental outcome at 9 to 10 years. These findings are of distinct importance for prediction of subsequent neurodevelopmental outcome in children with intrauterine growth retardation.

  12. Spatial Patterning of Newly-Inserted Material during Bacterial Cell Growth

    NASA Astrophysics Data System (ADS)

    Ursell, Tristan

    2012-02-01

    In the life cycle of a bacterium, rudimentary microscopy demonstrates that cell growth and elongation are essential characteristics of cellular reproduction. The peptidoglycan cell wall is the main load-bearing structure that determines both cell shape and overall size. However, simple imaging of cellular growth gives no indication of the spatial patterning nor mechanism by which material is being incorporated into the pre-existing cell wall. We employ a combination of high-resolution pulse-chase fluorescence microscopy, 3D computational microscopy, and detailed mechanistic simulations to explore how spatial patterning results in uniform growth and maintenance of cell shape. We show that growth is happening in discrete bursts randomly distributed over the cell surface, with a well-defined mean size and average rate. We further use these techniques to explore the effects of division and cell wall disrupting antibiotics, like cephalexin and A22, respectively, on the patterning of cell wall growth in E. coli. Finally, we explore the spatial correlation between presence of the bacterial actin-like cytoskeletal protein, MreB, and local cell wall growth. Together these techniques form a powerful method for exploring the detailed dynamics and involvement of antibiotics and cell wall-associated proteins in bacterial cell growth.[4pt] In collaboration with Kerwyn Huang, Stanford University.

  13. Synchrony between growth and reproductive patterns in human females: Early investment in growth among Pumé foragers.

    PubMed

    Kramer, Karen L; Greaves, Russell D

    2010-02-01

    Life history is an important framework for understanding many aspects of ontogeny and reproduction relative to fitness outcomes. Because growth is a key influence on the timing of reproductive maturity and age at first birth is a critical demographic variable predicting lifetime fertility, it raises questions about the synchrony of growth and reproductive strategies. Among the Pumé, a group of South American foragers, young women give birth to their first child on average at age 15.5. Previous research showed that this early age at first birth maximizes surviving fertility under conditions of high infant mortality. In this study we evaluate Pumé growth data to test the expectation that if early reproduction is advantageous, then girls should have a developmental trajectory that best prepares them for young childbearing. Analyses show that comparatively Pumé girls invest in skeletal growth early, enter puberty having achieved a greater proportion of adult body size and grow at low velocities during adolescence. For early reproducers growing up in a food-limited environment, a precocious investment in growth is advantageous because juveniles have no chance of pregnancy and it occurs before the onset of the competing metabolic demands of final reproductive maturation and childbearing. Documenting growth patterns under preindustrial energetic and demographic conditions expands the range of developmental variation not otherwise captured by normative growth standards and contributes to research on human phenotypic plasticity in diverse environments.

  14. Edge Effects on Growth of Ordered Stress Relief Patterns in Free Sustained Aluminum Films

    NASA Astrophysics Data System (ADS)

    Yu, Sen-Jiang; Zhang, Yong-Ju; Chen, Miao-Gen

    2010-06-01

    An unusual form of ordered stress relief patterns is observed in a nearly free sustained aluminum film system deposited on liquid substrates by the thermal evaporation method. The edge effects on the growth of the ordered patterns are systematically studied. It is found that the patterns initiate from the film edges, preexisting ordered patterns, or other imperfections of the film. When the patterns extend in the film regions, they decay gradually and finally disappear. If they develop along the boundaries, however, the sizes are almost unchanged over several millimeters. The stress relief patterns look like rectangular waves in appearance, which are proven to evolve from sinusoidal to triangular waves gradually. The morphological evolution can be well explained by the general theory of buckling of plates.

  15. Patterned growth and field-emission properties of AlN nanocones.

    PubMed

    Liu, Ning; Wu, Qiang; He, Chengyu; Tao, Haisheng; Wang, Xizhang; Lei, Wei; Hu, Zheng

    2009-09-01

    Patterned growth of AlN nanocones on a Ni-coated Si substrate is demonstrated through the reaction between AlCl(3) and NH(3) at 700 degrees C with Mo grid as a mask. The AlN nanocones are selectively deposited in the hollow region of the mask with diameters of approximately 10 nm at the tips and 50-60 nm at the roots. The field-emission (FE) performance is effectively enhanced by the patterned growth mainly because of the decreased screening effect, and both turn-on and threshold fields are dramatically decreased, less than half of the corresponding ones for the unpatterned product with similar sizes. The results indicate that patterned growth is an efficient and reproducible way to enhance the FE performance of AlN nanocones, which could be applied to optimize the FE properties of other nanoscale field emitters.

  16. Evolution of patterned GaAs(001) during homoepitaxial growth: Size versus spacing

    NASA Astrophysics Data System (ADS)

    Kan, H.-C.; Ankam, R.; Shah, S.; Micholsky, K. M.; Tadayyon-Eslami, T.; Calhoun, L.; Phaneuf, R. J.

    2006-05-01

    We report an extended experimental characterization of the transient evolution of the surface morphology of patterned GaAs(001) surfaces during homoepitaxial growth [Phys. Rev. Lett. 92, 146101 (2004)]. The size and the periodicity in the patterned structures are varied independently. Our results indicate different, nonmonotonic dependences of the evolution on these two characteristic distances. Numerical simulations of the growth based upon the conserved KPZ equation [Phys. Rev. A 40, 6763 (1989)] reproduce qualitatively the very different size and spacing dependences we observe during growth. We speculate on a physically based scenario in which a reduced collection efficiency on narrow terraces during growth breaks the up-down symmetry in the evolution of the surface topography.

  17. Co-immobilization of gradient-patterned growth factors for directed cell migration

    PubMed Central

    Stefonek-Puccinelli, Tracy Jane; Masters, Kristyn S.

    2009-01-01

    Cell migration is critically important for the repair of chronic wounds, which cost billions of dollars each year to treat and can lead to serious complications, including amputation and death. Growth factors, including epidermal growth factor (EGF) and insulin-like growth factor (IGF-1), are known to be deficient in chronic wounds; unfortunately, traditional delivery of soluble growth factors to wounds is expensive and complicated by their degradation. We have previously shown that directed and accelerated keratinocyte migration could be achieved by creating immobilized gradients of EGF. In this work, we have optimized EGF gradients for cell migration, synthesized and characterized gradient patterns of IGF-1, and tested for migration synergy upon combination of EGF and IGF-1 patterns. An optimal EGF concentration and pattern were identified, resulting in migration that was almost 10-fold that achieved on unpatterned controls. Immobilization of IGF-1 gradients also accelerated and directed keratinocyte migration (p<0.05), however, no difference in migration was found across various IGF-1 concentrations or gradient patterns. Although combining EGF with IGF-1 patterns did not accelerate migration beyond levels achieved using EGF alone, these methods can be applied to create other types of multi-component gradients that will ultimately be utilized to create 3-D bioactive wound dressings. PMID:18850272

  18. Association between facial growth pattern and facial muscle activity: A prospective cross-sectional study.

    PubMed

    Alabdullah, Mohannad; Saltaji, Humam; Abou-Hamed, Hussein; Youssef, Mohamed

    2015-06-01

    To evaluate the relationship between facial growth pattern and electromyography (EMG) of facial muscles: anterior temporalis, masseter, buccinators, orbicularis oris, mentalis and anterior digastric. The sample consisted of 77 subjects aged between 18-28 years (mean age 21.10±2.03), with dental Class I relationship, normal overjet and overbite, balanced facial profile, no signs of temporomandibular disorders, and no previous orthodontic treatment. Facial growth pattern was determined on the lateral cephalograms according to the Björk sum (sum of the N-S-Ar, S-Ar-Go, and Ar-Go-Me angles) dividing the sample into three groups: horizontal facial pattern group (24 subjects), normal facial pattern group (41 subjects), and vertical facial pattern group (12 subjects). The EMG of anterior temporalis, masseter, buccinator, orbicularis oris, mentalis and anterior digastric muscles were examined for each patient in the rest position and in functional positions (central maximum intercuspation, chewing on right side, chewing on left side and swallowing). Mean values and standard deviation of EMG were obtained and compared between the three groups. At rest, the EMG of the masseter, orbicularis oris and anterior digastric were higher in the vertical facial pattern group compared with the other two groups, with a moderate positive correlation between the EMG of these muscles and the Björk sum (P<.01). In contrast, during central maximum intercuspation, the activity of the anterior temporalis, masseter and buccinator was significantly lower in the vertical facial pattern group compared with the two other groups, with a moderate negative correlation between the Björk sum and EMG in the maximum central intercuspation position of these muscles (P<.01). A significant relationship was found between facial muscle activity and facial growth pattern. The findings suggest that the activity of masticatory and perioral muscles could play a role in the direction of the facial growth

  19. Spatially Directed Guidance of Stem Cell Population Migration by Immobilized Patterns of Growth Factors

    PubMed Central

    Miller, Eric D.; Li, Kang; Kanade, Takeo; Weiss, Lee E.; Walker, Lynn M.; Campbell, Phil G.

    2011-01-01

    We investigated how engineered gradients of exogenous growth factors, immobilized to an extracellular matrix material, influence collective guidance of stem cell populations over extended time (>1 day) and length (>1 mm) scales in vitro. Patterns of low-to-high, high-to-low, and uniform concentrations of heparin-binding epidermal growth factor-like growth factor were inkjet printed at precise locations on fibrin substrates. Proliferation and migration responses of mesenchymal stem cells seeded at pattern origins were observed with time-lapse video microscopy and analyzed using both manual and automated computer vision-based cell tracking techniques. Based on results of established chemotaxis studies, we expected that the low-to-high gradient would most effectively direct cell guidance away from the cell source. All printed patterns, however, were found to direct net collective cell guidance with comparable responses. Our analysis revealed that collective “cell diffusion” down a cell-to-cell confinement gradient originating at the cell starting lines and not the net sum of directed individual cell migration up a growth factor concentration gradient is the principal driving force for directing mesenchymal stem cell population outgrowth from a cell source. These results suggest that simple uniform distributions of growth factors immobilized to an extracellular matrix material may be as effective in directing cell migration into a wound site as more complex patterns with concentration gradients. PMID:21272933

  20. Relationships between winter atmospheric circulation patterns and extreme tree growth anomalies in the Sierra Nevada

    NASA Astrophysics Data System (ADS)

    Garfin, Gregg M.

    1998-06-01

    Tree-ring data from mid-elevation (2000 m) giant sequoia (Sequoiadendron giganteum) and high elevation (3500 m) pines (Pinus balfouriana, Pinus albicaulis) were used to select extreme growth years from which temperature, precipitation and large-scale winter (November-March, NM) 500 mb circulation patterns associated with the extreme tree growth anomalies were examined.Winters preceding extreme high growth in both giant sequoia and pines are warm and wet and are characterized by anomalous low pressure in the northeastern Pacific Ocean and a tendency for southwesterly flow and advection of warm maritime air into California. For the pines, such winters exhibit a pattern of anomalous low pressure in the northern Pacific, anomalous high pressure over northwestern Canada and anomalous low pressure across the southern US. NM 500 mb heights suggest more meridional circulation during the warm and dry winters preceding extreme low growth in giant sequoia. Atmospheric circulation during these winters exhibits a persistent trough/ridge pattern between the central Pacific and the western US. Storms are deflected away from California during these winters. NM atmospheric circulation patterns associated with extreme low growth in the pines exhibit maximum westerlies north of their mean position and the tendency for enhanced ridging in the northeast Pacific, which advects cool dry air into the Sierra Nevada. As dendroclimatic reconstructions are more frequently employed in order to better understand past variability of temperature and precipitation, synoptic dendroclimatological studies such as this one provide useful insights about atmospheric circulation.

  1. Transient Evolution of Surface Roughness on Patterned GaAs(001) during Homoepitaxial Growth

    NASA Astrophysics Data System (ADS)

    Kan, H.-C.; Shah, S.; Tadyyon-Eslami, T.; Phaneuf, R. J.

    2004-04-01

    We have investigated the length scale dependence of the transient evolution of surface roughness during homoepitaxial growth on GaAs(100), patterning the surface lithographically with an array of cylindrical pits of systematically varied sizes and spacings. Our atomic force microscopy measurements show that the amplitude of the surface corrugation has nonmonotonic behavior in both the length scale dependence and time evolution. This behavior allows us to rule out a number of existing continuum models of growth.

  2. Control of Organ Growth by Patterning and Hippo Signalling in Drosophila

    PubMed Central

    Irvine, Kenneth D.; Harvey, Kieran F.

    2017-01-01

    Control of organ size is of fundamental importance and is controlled by genetic, environmental and mechanical factors. Studies in many species have pointed to the existence of both organ-extrinsic and organ-intrinsic size control mechanisms, which ultimately must coordinate to regulate organ size. Here we discuss organ size control by organ patterning and by the Hippo pathway, which both act in an organ-intrinsic fashion. The influence of morphogens and other patterning molecules couples growth and patterning, whilst emerging evidence suggests that the Hippo pathway controls growth in response to mechanical stimuli and signals emanating from cell-cell interactions. Several points of crosstalk have been reported between signalling pathways that control organ patterning and the Hippo pathway, both at the level of membrane receptors and transcriptional regulators. However, despite substantial progress in the past decade, key questions in the growth control field remain, including precisely how and when organ patterning and the Hippo pathway communicate to control size and whether these communication mechanisms are organ-specific or general. In addition, elucidating mechanisms by which organ-intrinsic cues such as patterning factors and the Hippo pathway interface with extrinsic cues such as hormones to control organ size remains unresolved. PMID:26032720

  3. Characteristics of proportionate growth observed in instability patterns of miscible fluids

    NASA Astrophysics Data System (ADS)

    Bischofberger, Irmgard; Ramachandran, Radha; Nagel, Sidney R.; Nagel lab Team

    2014-11-01

    As a baby mammal grows, different parts of its body develop at the nearly the same rate and thus to a good approximation in direct proportion to one another. This type of growth is called proportionate growth. As familiar as it appears to us, it is very rarely found in physical systems outside of the biological world. We here show an example of proportionate growth that occurs in the instability formed when a less viscous liquid, of viscosity ηin displaces a more viscous miscible one, of viscosity ηout. We investigate the growth of these patterns in a quasi-two-dimensional geometry. Within a range of viscosity ratios 0.1 <ηin /ηout <0.3, we observe the formation of small blunt structures that form at the edges of an inner circular region devoid of fingers. As the pattern grows, the size of these structures increases in proportion to the size of the inner circle, such that even small details in the shape of the pattern remain essentially unchanged during growth. These characteristics of proportionate growth are reflected in the shape of the interface in the third dimension as well.

  4. Modeling and predicting urban growth pattern of the Tokyo metropolitan area based on cellular automata

    NASA Astrophysics Data System (ADS)

    Zhao, Yaolong; Zhao, Junsan; Murayama, Yuji

    2008-10-01

    The period of high economic growth in Japan which began in the latter half of the 1950s led to a massive migration of population from rural regions to the Tokyo metropolitan area. This phenomenon brought about rapid urban growth and urban structure changes in this area. Purpose of this study is to establish a constrained CA (Cellular Automata) model with GIS (Geographical Information Systems) to simulate urban growth pattern in the Tokyo metropolitan area towards predicting urban form and landscape for the near future. Urban land-use is classified into multi-categories for interpreting the effect of interaction among land-use categories in the spatial process of urban growth. Driving factors of urban growth pattern, such as land condition, railway network, land-use zoning, random perturbation, and neighborhood interaction and so forth, are explored and integrated into this model. These driving factors are calibrated based on exploratory spatial data analysis (ESDA), spatial statistics, logistic regression, and "trial and error" approach. The simulation is assessed at both macro and micro classification levels in three ways: visual approach; fractal dimension; and spatial metrics. Results indicate that this model provides an effective prototype to simulate and predict urban growth pattern of the Tokyo metropolitan area.

  5. Sporulation patterning and invasive growth in wild and domesticated yeast colonies

    PubMed Central

    Piccirillo, Sarah; Honigberg, Saul M.

    2010-01-01

    Different cell types can form patterns within fungal communities; for example, colonies of Saccharomyces cerevisiae form two sharply defined layers of sporulating cells separated by an intervening layer of unsporulated cells. Because colony sporulation patterns have only been investigated in a single laboratory strain background (W303), in this report we examined these patterns in other strain backgrounds. Two other laboratory strain backgrounds (SK1 and Σ1278b) that differ from W303 with respect to colony morphology, invasive growth, and sporulation efficiency nevertheless displayed the same colony sporulation pattern as W303. This pattern was also observed in colonies of wild isolates of S. cerevisiae and S. paradoxus. The wild yeast colonies sporulated on a much wider range of carbon sources than did the lab yeast and displayed a similar layered sporulation pattern when grown on either acetate or glucose medium and on either rich or synthetic medium. SK1 and Σ1278b and wild yeast colonies invaded the agar surface. The region of invasion varied between strains with respect to the organization and appearance of cells, but this invasion was always accompanied by sporulation. Thus, sporulation patterns are a general property of S. cerevisiae, and sporulation in colonies can be coordinated with invasive growth. PMID:20420901

  6. Postnatal changes in the growth dynamics of the human face revealed from bone modelling patterns

    PubMed Central

    Martinez-Maza, Cayetana; Rosas, Antonio; Nieto-Díaz, Manuel

    2013-01-01

    Human skull morphology results from complex processes that involve the coordinated growth and interaction of its skeletal components to keep a functional and structural balance. Previous histological works have studied the growth of different craniofacial regions and their relationship to functional spaces in humans up to 14 years old. Nevertheless, how the growth dynamics of the facial skeleton and the mandible are related and how this relationship changes through the late ontogeny remain poorly understood. To approach these two questions, we have compared the bone modelling activities of the craniofacial skeleton from a sample of subadult and adult humans. In this study, we have established for the first time the bone modelling pattern of the face and the mandible from adult humans. Our analyses reveal a patchy distribution of the bone modelling fields (overemphasized by the presence of surface islands with no histological information) reflecting the complex growth dynamics associated to the individual morphology. Subadult and adult specimens show important differences in the bone modelling patterns of the anterior region of the facial skeleton and the posterior region of the mandible. These differences indicate developmental changes in the growth directions of the whole craniofacial complex, from a predominantly downward growth in subadults that turns to a forward growth observed in the adult craniofacial skeleton. We hypothesize that these ontogenetic changes would respond to the physiological and physical requirements to enlarge the oral and nasal cavities once maturation of the brain and the closure of the cranial sutures have taken place during craniofacial development. PMID:23819603

  7. Acta stomatologica Croatica and PubMed Central

    PubMed Central

    Brkić, Hrvoje

    2016-01-01

    April 15 2016 marked the 50th anniversary of continuous publishing of the journal Acta stomatologica Croatica (ASCRO). The celebration was held in the great hall of the Croatian Medical Association, with numerous guests from the biomedical field. The history of the journal was presented by Goran Knežević (editor-in-chief 1996-2006) and Hrvoje Brkić (current editor-in-chief), who presented all the current information on the electronical editing and its current indexation. Only a few days later, the Editorial Office received the information that ASCRO has been included in PubMed Central since volume 48, an impulse for the members of the Editorial Board and the Editor-in-Chief to make ASCRO better and more cited PMID:27789906

  8. Patterns of Geographic Synchrony in Growth and Reproduction of Oaks Within California and Beyond

    Treesearch

    Walter D. Koenig; Johannes M.H. Knops

    1997-01-01

    We measured patterns of spatial synchrony in growth and reproduction by oaks using direct acorn surveys, published data on acorn production, and tree-ring chronologies. The two data sets involving acorn production both indicate that acorn crops are detectably synchronous over areas of at least 500 to 1,000 km not only within individual species but among species that...

  9. Hydraulic redistribution of soil water in two old-growth coniferous forests: quantifying patterns and controls.

    Treesearch

    J.M. Warren; F.C. Meinzer; J.R. Brooks; J.-C. Domec; R. Coulombe

    2006-01-01

    We incorporated soil/plant biophysical properties into a simple model to predict seasonal trajectories of hydraulic redistribution (HR). We measured soil water content, water potential root conductivity, and climate across multiple years in two old-growth coniferous forests. The HR variability within sites (0 to 0.5 mm/d) was linked to spatial patterns of roots, soil...

  10. A Longitudinal Solution to the Problem of Differential Linear Growth Patterns in Quasi-Experiments.

    ERIC Educational Resources Information Center

    Olejnik, Stephen; Porter, Andrew C.

    Differential achievement growth patterns between comparison groups is a problem associated with data analysis in compensatory education programs. Children in greatest need of additional assistance, are usually assigned to the program rather than to an alternative treatment so that the comparison groups may vary in several ways, in addition to the…

  11. Effect of weather patterns on preweaning growth of beef calves in the Northern Great Plains

    USDA-ARS?s Scientific Manuscript database

    Beef production records collected over a 76-year investigation into effects of linebreeding and selection of Hereford cattle, and concurrent weather records were used to assess effects of weather patterns on the growth of calves from birth to weaning. Data were simultaneously adjusted for trends in ...

  12. Growth patterns of Tsuga canadensis in managed uneven-aged northern conifer stands

    Treesearch

    Laura S. Kenefic; Robert S. Seymour

    2000-01-01

    This study reports patterns of regeneration and growth for 100 eastern hemlock (Tsuga canadensis (L.) Carr.) up to 20 inches (50 cm) dbh in two mixed-species selection stands on the Penobscot Experimental Forest in east-central Maine. The study stands are part of a U.S.D.A. Forest Service experiment in which eastern hemlock has remained stable over a...

  13. Object-based algorithms and methods for quantifying urban growth pattern using sequential satellite images

    NASA Astrophysics Data System (ADS)

    Yu, Bailang; Liu, Hongxing; Gao, Yige; Wu, Jianping

    2008-08-01

    Previously, urban growth pattern is described and measured by the pixel-by-pixel comparison of satellite images. The geographic extent, patterns and types of urban growth are derived from satellite images separated in time. However, the pixel-by-pixel comparison approach suffers from several drawbacks. Firstly, slight error in image geo-reference can cause false detection of changes. Secondly, it's difficult to recognize and correct artifact changes induced by data noise and data processing errors. Thirdly, only limited information can be derived. In this paper, we present a new objectbased method to describe and quantify urban growth patterns. The different types of land cover are classified from sequential satellite images as urban objects. The geometric and shape attributes of objects and the spatial relationship between them are employed to identify the different types of urban growth pattern. The algorithms involved in the object-based method are implemented by using C++ programming language and the software user interface is developed by using ArcObjects and VB.Net. A simulated example is given to demonstrate the utility and effectiveness of this new method.

  14. Controlled neuronal cell patterning and guided neurite growth on micropatterned nanofiber platforms

    NASA Astrophysics Data System (ADS)

    Malkoc, Veysi; Gallego-Perez, Daniel; Nelson, Tyler; Lannutti, John J.; Hansford, Derek J.

    2015-12-01

    Patterning neuronal cells and guiding neurite growth are important for applications such as prosthetics, cell based biosensors, and tissue engineering. In this paper, a microdevice is presented that provides neuronal cell patterning and guided neurite growth on a collagen coated gelatin/PCL nanofiber mat. The pattern consisted of a grid of polystyrene microwells/nodes to confine the cell bodies and orthogonal grooves to guide neurite growth from each node. Vacuum assisted cell seeding was used to localize cell bodies in the microwells and physically separate the cells during seeding. The electrospun nanofiber mats under the polystyrene microstructures were coated with collagen to enhance the cellular attachment and enhance differentiation. We evaluated the performance of our device using adhesion, viability, and differentiation assays of neuron-like PC12 cells compared to controls for vacuum seeding, spatial isolation and guidance, and collagen coating of the fibers. The device provided PC12 cell patterning with increased adhesion, differentiation, and guided neurite outgrowth compared to controls, demonstrating its potential for in vitro neuronal cell patterning studies.

  15. Gender perceptions predict sex differences in growth patterns of indigenous Guatemalan infants and young children.

    PubMed

    Tumilowicz, Alison; Habicht, Jean-Pierre; Pelto, Gretel; Pelletier, David L

    2015-11-01

    Nearly one-half of Guatemalan children experience growth faltering, more so in indigenous than in nonindigenous children. On the basis of ethnographic interviews in Totonicapán, Guatemala, which revealed differences in maternal perceptions about food needs in infant girls and boys, we predicted a cumulative sex difference in favor of girls that occurred at ∼6 mo of age and diminished markedly thereafter. We examined whether the predicted differences in age-sex patterns were observed in the village, replicated the examination nationally for indigenous children, and examined whether the pattern in nonindigenous children was different. Ethnographic interviews (n = 24) in an indigenous village were conducted. Anthropometric measurements of the village children aged 0-35 mo (n = 119) were obtained. National-level growth patterns were analyzed for indigenous (n = 969) and nonindigenous (n = 1374) children aged 0-35 mo with the use of Demographic and Health Survey (DHS) data. Mothers reported that, compared with female infants, male infants were hungrier, were not as satisfied with breastfeeding alone, and required earlier complementary feeding. An anthropometric analysis confirmed the prediction of healthier growth in indigenous girls than in indigenous boys throughout the first year of life, which resulted in a 2.98-cm height-for-age difference (HAD) between sexes in the village and a 1.61-cm HAD (P < 0.001) in the DHS data between 6 and 17 mo of age in favor of girls. In both data sets, the growth sex differences diminished in the second year of life (P < 0.05). No such pattern was seen in nonindigenous children. We propose that the differences in the HAD that first favor girls and then favor boys in the indigenous growth patterns are due to feeding patterns on the basis of gendered cultural perceptions. Circumstances that result in differential sex growth patterns need to be elucidated, in particular the favorable growth in girls in the first year of life. © 2015

  16. Selective growth of α-sexithiophene by using silicon oxides patterns.

    PubMed

    Albonetti, Cristiano; Barbalinardo, Marianna; Milita, Silvia; Cavallini, Massimiliano; Liscio, Fabiola; Moulin, Jean-François; Biscarini, Fabio

    2011-01-01

    A process for fabricating ordered organic films on large area is presented. The process allows growing sexithiophene ultra-thin films at precise locations on patterned Si/SiO(x) substrates by driving the orientation of growth. This process combines the parallel local anodic oxidation of Si/SiO(x) substrates with the selective arrangement of molecular ultra-thin film. The former is used to fabricate silicon oxide arrays of parallel lines of 400 nm in width over an area of 1 cm(2). Selective growth arises from the interplay between kinetic growth parameters and preferential interactions with the patterned surface. The result is an ultra-thin film of organic molecules that is conformal to the features of the fabricated motives.

  17. Diel growth patterns of young soybean (Glycine max) leaflets are synchronous throughout different positions on a plant.

    PubMed

    Friedli, Michael; Walter, Achim

    2015-03-01

    Leaf growth is controlled by various internal and external factors. Leaves of dicotyledonous plants show pronounced diel (24 h) growth patterns that are controlled by the circadian clock. To date, it is still uncertain whether diel leaf growth patterns remain constant throughout the development of a plant. In this study, we followed growth from the primary leaves to leaflets of the seventh trifoliate leaf of soybean (Glycine max) on the same plants with a recently developed imaging-based method under controlled conditions and at a high temporal resolution. We found that all leaflets displayed a consistent diel growth pattern with maximum growth towards the end of the night. In some leaves, growth maxima occurred somewhat later - at dawn - as long as the leaves were still in a very early developmental stage. Yet, overall, diel growth patterns of leaves from different positions within the canopy were highly synchronous. Therefore, the diel growth pattern of any leaf at a given point in time is representative for the overall diel growth pattern of the plant leaf canopy and a deviation from the normal diel growth pattern can indicate that the plant is currently facing stress.

  18. Pattern Selection in Plants: Coupling Chemical Dynamics to Surface Growth in Three Dimensions

    PubMed Central

    Holloway, David M.; Harrison, Lionel G.

    2008-01-01

    Background and Aims A study is made by computation of the interplay between the pattern formation of growth catalysts on a plant surface and the expansion of the surface to generate organismal shape. Consideration is made of the localization of morphogenetically active regions, and the occurrence within them of symmetry-breaking processes such as branching from an initially dome-shaped tip or meristem. Representation of a changing and growing three-dimensional shape is necessary, as two-dimensional work cannot distinguish, for example, formation of an annulus from dichotomous branching. Methods For the formation of patterns of chemical concentrations, the Brusselator reaction-diffusion model is used, applied on a hemispherical shell and generating patterns that initiate as surface spherical harmonics. The initial shape is hemispherical, represented as a mesh of triangles. These are combined into finite elements, each made up of all the triangles surrounding each node. Chemical pattern is converted into shape change by moving nodes outwards according to the concentration of growth catalyst at each, to relieve misfits caused by area increase of the finite element. New triangles are added to restore the refinement of the mesh in rapidly growing regions. Key Results The postulated mechanism successfully generates: tip growth (or stalk extension by an apical meristem) to ten times original hemisphere height; tip flattening and resumption of apical advance; and dichotomous branching and higher-order branching to make whorled structures. Control of the branching plane in successive dichotomous branchings is tackled with partial success and clarification of the issues. Conclusions The representation of a growing plant surface in computations by an expanding mesh that has no artefacts constraining changes of shape and symmetry has been achieved. It is shown that one type of pattern-forming mechanism, Turing-type reaction-diffusion, acting within a surface to pattern a

  19. Patterning Expression of Regenerative Growth Factors Using High Intensity Focused Ultrasound

    PubMed Central

    Wilson, Christopher G.; Martín-Saavedra, Francisco M.; Padilla, Frédéric; Fabiilli, Mario L.; Zhang, Man; Baez, Alexander M.; Bonkowski, Christopher J.; Kripfgans, Oliver D.; Voellmy, Richard; Vilaboa, Nuria; Fowlkes, J. Brian

    2014-01-01

    Temporal and spatial control of growth factor gradients is critical for tissue patterning and differentiation. Reinitiation of this developmental program is also required for regeneration of tissues during wound healing and tissue regeneration. Devising methods for reconstituting growth factor gradients remains a central challenge in regenerative medicine. In the current study we develop a novel gene therapy approach for temporal and spatial control of two important growth factors in bone regeneration, vascular endothelial growth factor, and bone morphogenetic protein 2, which involves application of high intensity focused ultrasound to cells engineered with a heat-activated- and ligand-inducible gene switch. Induction of transgene expression was tightly localized within cell-scaffold constructs to subvolumes of ∼30 mm3, and the amplitude and projected area of transgene expression was tuned by the intensity and duration of ultrasound exposure. Conditions for ultrasound-activated transgene expression resulted in minimal cytotoxicity and scaffold damage. Localized regions of growth factor expression also established gradients in signaling activity, suggesting that patterns of growth factor expression generated by this method will have utility in basic and applied studies on tissue development and regeneration. PMID:24460731

  20. Eye Size at Birth in Prosimian Primates: Life History Correlates and Growth Patterns

    PubMed Central

    Cummings, Joshua R.; Muchlinski, Magdalena N.; Kirk, E. Christopher; Rehorek, Susan J.; DeLeon, Valerie B.; Smith, Timothy D.

    2012-01-01

    Background Primates have large eyes relative to head size, which profoundly influence the ontogenetic emergence of facial form. However, growth of the primate eye is only understood in a narrow taxonomic perspective, with information biased toward anthropoids. Methodology/Principal Findings We measured eye and bony orbit size in perinatal prosimian primates (17 strepsirrhine taxa and Tarsius syrichta) to infer the extent of prenatal as compared to postnatal eye growth. In addition, multiple linear regression was used to detect relationships of relative eye and orbit diameter to life history variables. ANOVA was used to determine if eye size differed according to activity pattern. In most of the species, eye diameter at birth measures more than half of that for adults. Two exceptions include Nycticebus and Tarsius, in which more than half of eye diameter growth occurs postnatally. Ratios of neonate/adult eye and orbit diameters indicate prenatal growth of the eye is actually more rapid than that of the orbit. For example, mean neonatal transverse eye diameter is 57.5% of the adult value (excluding Nycticebus and Tarsius), compared to 50.8% for orbital diameter. If Nycticebus is excluded, relative gestation age has a significant positive correlation with relative eye diameter in strepsirrhines, explaining 59% of the variance in relative transverse eye diameter. No significant differences were found among species with different activity patterns. Conclusions/Significance The primate developmental strategy of relatively long gestations is probably tied to an extended period of neural development, and this principle appears to apply to eye growth as well. Our findings indicate that growth rates of the eye and bony orbit are disassociated, with eyes growing faster prenatally, and the growth rate of the bony orbit exceeding that of the eyes after birth. Some well-documented patterns of orbital morphology in adult primates, such as the enlarged orbits of nocturnal species

  1. Retarded fetal growth patterns and early neonatal mortality in a Mexico City population.

    PubMed

    Balcazar, H; Haas, J D

    1991-01-01

    The study reported here classified 9,660 newborn infants delivered at a maternal and child health center in Mexico City by length of gestation, presence or absence of growth retardation, and (in the case of growth-retarded infants) proportionate or disproportionate growth retardation in terms of the infants' weight and length. It was found that preterm infants (delivered before 38 weeks of gestation) had nine times the early neonatal mortality of term infants, irrespective of growth retardation patterns. Also, the type of fetal growth retardation involved (proportionate or disproportionate) in those cases where such retardation was present was found to have an impact on early neonatal mortality. That is, preterm and term infants classified as having proportionate growth retardation respectively exhibited 1.5 and 9.5 times the early neonatal mortality of preterm and term infants with disproportionate growth retardation. Among other things, these findings suggest a need for assessing types of growth retardation as well as etiologic factors when evaluating mortality risk in newborns.

  2. Spatially controlled simultaneous patterning of multiple growth factors in three-dimensional hydrogels

    NASA Astrophysics Data System (ADS)

    Wylie, Ryan G.; Ahsan, Shoeb; Aizawa, Yukie; Maxwell, Karen L.; Morshead, Cindi M.; Shoichet, Molly S.

    2011-10-01

    Three-dimensional (3D) protein-patterned scaffolds provide a more biomimetic environment for cell culture than traditional two-dimensional surfaces, but simultaneous 3D protein patterning has proved difficult. We developed a method to spatially control the immobilization of different growth factors in distinct volumes in 3D hydrogels, and to specifically guide differentiation of stem/progenitor cells therein. Stem-cell differentiation factors sonic hedgehog (SHH) and ciliary neurotrophic factor (CNTF) were simultaneously immobilized using orthogonal physical binding pairs, barnase-barstar and streptavidin-biotin, respectively. Barnase and streptavidin were sequentially immobilized using two-photon chemistry for subsequent concurrent complexation with fusion proteins barstar-SHH and biotin-CNTF, resulting in bioactive 3D patterned hydrogels. The technique should be broadly applicable to the patterning of a wide range of proteins.

  3. Unraveling a generic growth pattern in structure evolution of thiolate-protected gold nanoclusters

    NASA Astrophysics Data System (ADS)

    Xu, Wen Wu; Li, Yadong; Gao, Yi; Zeng, Xiao Cheng

    2016-03-01

    Precise control of the growth of thiolate-protected gold nanoclusters is a prerequisite for their applications in catalysis and bioengineering. Here, we bring to bear a new series of thiolate-protected nanoclusters with a unique growth pattern, i.e., Au20(SR)16, Au28(SR)20, Au36(SR)24, Au44(SR)28, and Au52(SR)32. These nanoclusters can be viewed as resulting from the stepwise addition of a common structural motif [Au8(SR)4]. The highly negative values of the nucleus-independent chemical shift (NICS) in the center of the tetrahedral Au4 units suggest that the overall stabilities of these clusters stem from the local stability of each tetrahedral Au4 unit. Generalization of this growth-pattern rule to large-sized nanoclusters allows us to identify the structures of three new thiolate-protected nanoclusters, namely, Au60(SR)36, Au68(SR)40, and Au76(SR)44. Remarkably, all three large-sized nanoclusters possess relatively large HOMO-LUMO gaps and negative NICS values, suggesting their high chemical stability. Further extension of the growth-pattern rule to the infinitely long nanowire limit results in a one-dimensional (1D) thiolate-protected gold nanowire (RS-AuNW) with a band gap of 0.78 eV. Such a unique growth-pattern rule offers a guide for precise synthesis of a new class of large-sized thiolate-protected gold nanoclusters or even RS-AuNW which, to our knowledge, has not been reported in the literature.Precise control of the growth of thiolate-protected gold nanoclusters is a prerequisite for their applications in catalysis and bioengineering. Here, we bring to bear a new series of thiolate-protected nanoclusters with a unique growth pattern, i.e., Au20(SR)16, Au28(SR)20, Au36(SR)24, Au44(SR)28, and Au52(SR)32. These nanoclusters can be viewed as resulting from the stepwise addition of a common structural motif [Au8(SR)4]. The highly negative values of the nucleus-independent chemical shift (NICS) in the center of the tetrahedral Au4 units suggest that the overall

  4. Patterned growth of carbon nanotubes obtained by high density plasma chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Mousinho, A. P.; Mansano, R. D.

    2015-03-01

    Patterned growth of carbon nanotubes by chemical vapor deposition represents an assembly approach to place and orient nanotubes at a stage as early as when they are synthesized. In this work, the carbon nanotubes were obtained at room temperature by High Density Plasmas Chemical Vapor Deposition (HDPCVD) system. This CVD system uses a new concept of plasma generation, where a planar coil coupled to an RF system for plasma generation was used with an electrostatic shield for plasma densification. In this mode, high density plasmas are obtained. We also report the patterned growth of carbon nanotubes on full 4-in Si wafers, using pure methane plasmas and iron as precursor material (seed). Photolithography processes were used to pattern the regions on the silicon wafers. The carbon nanotubes were characterized by micro-Raman spectroscopy, the spectra showed very single-walled carbon nanotubes axial vibration modes around 1590 cm-1 and radial breathing modes (RBM) around 120-400 cm-1, confirming that high quality of the carbon nanotubes obtained in this work. The carbon nanotubes were analyzed by atomic force microscopy and scanning electron microscopy too. The results showed that is possible obtain high-aligned carbon nanotubes with patterned growth on a silicon wafer with high reproducibility and control.

  5. Patterned growth of tungsten oxide and tungsten oxynitride nanorods from Au-coated W foil.

    PubMed

    Xu, Fang; Fahmi, Amir; Zhao, Yimin; Xia, Yongde; Zhu, Yanqiu

    2012-11-21

    This manuscript first describes a simple synthesis of tungsten oxide (WO(x)) nanorods from templated W foil using a chemical vapour deposition (CVD) technique at 600-750 °C, then presents the formation of tungsten oxynitride (WO(x)N(y)) nanorods via nitridation at 650 °C for different reaction times. The W foil, blade engraved, acid etched, or spin coated with Au-block copolymer composites then plasma etched, was used as a substrate for the nanorod growth. The Au patterns that were created on the surface of a W foil following the removal of the copolymer, led to a reverse patterned growth of WO(x) nanorods on the Au free areas. Consequently, following the oxide-to-nitride conversion, WO(x)N(y) nanorods were obtained with an identical patterned feature as to that of the parental WO(x). Combined techniques including XRD, SEM, TEM and Raman were used to visualise and analyse the resulting WO(x) and WO(x)N(y) nanorods. The diameter, length, and chemical composition of the nanorods are found to vary with reaction time and temperatures, as well as different substrate pre-treatments. This result represents a simple, innovative and efficient process for reverse-patterned growth of new nanomaterials.

  6. A simple method for understanding the triangular growth patterns of transition metal dichalcogenide sheets

    SciTech Connect

    Zhu, Siya; Wang, Qian

    2015-10-15

    Triangular nanoflake growth patterns have been commonly observed in synthesis of transition metal dichalcogenide sheets and their hybrid structures. Triangular nanoflakes not only show exceptional properties, but also can serve as building blocks for two or three dimensional structures. In this study, taking the MoS{sub 2} system as a test case, we propose a Matrix method to understand the mechanism of such unique growth pattern. Nanoflakes with different edge types are mathematically described with configuration matrices, and the total formation energy is calculated as the sum of the edge formation energies and the chemical potentials of sulfur and molybdenum. Based on energetics, we find that three triangular patterns with the different edge configurations are energetically more favorable in different ranges of the chemical potential of sulfur, which are in good agreement with experimental observations. Our algorithm has high efficiency and can deal with nanoflakes in microns which are beyond the ability of ab-initio method. This study not only elucidates the mechanism of triangular nanoflake growth patterns in experiment, but also provides a clue to control the geometric configurations in synthesis.

  7. Quantifying Two-Dimensional Filamentous and Invasive Growth Spatial Patterns in Yeast Colonies

    PubMed Central

    Binder, Benjamin J.; Sundstrom, Joanna F.; Gardner, Jennifer M.; Jiranek, Vladimir; Oliver, Stephen G.

    2015-01-01

    The top-view, two-dimensional spatial patterning of non-uniform growth in a Saccharomyces cerevisiae yeast colony is considered. Experimental images are processed to obtain data sets that provide spatial information on the cell-area that is occupied by the colony. A method is developed that allows for the analysis of the spatial distribution with three metrics. The growth of the colony is quantified in both the radial direction from the centre of the colony and in the angular direction in a prescribed outer region of the colony. It is shown that during the period of 100–200 hours from the start of the growth of the colony there is an increasing amount of non-uniform growth. The statistical framework outlined in this work provides a platform for comparative quantitative assays of strain-specific mechanisms, with potential implementation in inferencing algorithms used for parameter-rate estimation. PMID:25719406

  8. Morphogen-based simulation model of ray growth and joint patterning during fin development and regeneration.

    PubMed

    Rolland-Lagan, Anne-Gaëlle; Paquette, Mathieu; Tweedle, Valerie; Akimenko, Marie-Andrée

    2012-03-01

    The fact that some organisms are able to regenerate organs of the correct shape and size following amputation is particularly fascinating, but the mechanism by which this occurs remains poorly understood. The zebrafish (Danio rerio) caudal fin has emerged as a model system for the study of bone development and regeneration. The fin comprises 16 to 18 bony rays, each containing multiple joints along its proximodistal axis that give rise to segments. Experimental observations on fin ray growth, regeneration and joint formation have been described, but no unified theory has yet been put forward to explain how growth and joint patterns are controlled. We present a model for the control of fin ray growth during development and regeneration, integrated with a model for joint pattern formation, which is in agreement with published, as well as new, experimental data. We propose that fin ray growth and joint patterning are coordinated through the interaction of three morphogens. When the model is extended to incorporate multiple rays across the fin, it also accounts for how the caudal fin acquires its shape during development, and regains its correct size and shape following amputation.

  9. [Postnatal growth patterns in eight species of herons and egrets (Ciconiiformes: Ardeidae)].

    PubMed

    Avila, Dennis Denis

    2011-06-01

    Avian postnatal growth has received considerable attention and its ecological implications have been deeply analyzed. In this current paper, I describe the patterns of culmen and tarsus growth, as well as of weight gain patterns in eight species of herons and egrets (Aves: Ardeidae) found in the Birama Swamp in Eastern Cuba. Between 1998 and 2006,714 nestlings of the following species were measured every two days: Butorides virescens, Bubulcus ibis, Egretta thula, E. tricolor, E. caerulea, E. rufescens, Ardea alba and Nycticorax nycticorax. Logistic and Gompertz equations were adjusted to data using non-lineal regression models with adult values as the asymptote. For each species, the following were determined and recorded: growth rate, age at inflexion, instantaneous growth rates at each age interval, and time taken to reach 90% of adult size. Reported hatchling sizes were similar in other localities, with a variation coefficient ranging between 10-19%. At hatch, each species exhibited differing sizes relative to adult values. In all cases, Gompertz equations were best fitted to explain more variance and lesser residuals. Rates of weight change and tarsus growth were alometrically related to the log of adult weight. Two main growth processes were identified: a physical extension in dimensions of each measurement reflecting inter-specific morphometric differences, and a lineal increase of the growth period from Green Heron to Great Egret. The Black-crowned Night Heron, Cattle Egret and Reddish Egret exhibited some unique measurement characteristics in comparison to the remaining members of the family. All results support the hypothesis that hypermorphosis, as the main evolutionary process in the microevolution of Ardeidae, is caused by a delayed final moment of growth.

  10. Growth plate cartilage shows different strain patterns in response to static versus dynamic mechanical modulation.

    PubMed

    Kaviani, Rosa; Londono, Irene; Parent, Stefan; Moldovan, Florina; Villemure, Isabelle

    2016-08-01

    Longitudinal growth of long bones and vertebrae occurs in growth plate cartilage. This process is partly regulated by mechanical forces, which are one of the underlying reasons for progression of growth deformities such as idiopathic adolescent scoliosis and early-onset scoliosis. This concept of mechanical modulation of bone growth is also exploited in the development of fusionless treatments of these deformities. However, the optimal loading condition for the mechanical modulation of growth plate remains to be identified. The objective of this study was to evaluate the effects of in vitro static versus dynamic modulation and of dynamic loading parameters, such as frequency and amplitude, on the mechanical responses and histomorphology of growth plate explants. Growth plate explants from distal ulnae of 4-week-old swines were extracted and randomly distributed among six experimental groups: baseline ([Formula: see text]), control ([Formula: see text]), static ([Formula: see text]) and dynamic ([Formula: see text]). For static and dynamic groups, mechanical modulation was performed in vitro using an Indexed CartiGen bioreactor. A stress relaxation test combined with confocal microscopy and digital image correlation was used to characterize the mechanical responses of each explant in terms of peak stress, equilibrium stress, equilibrium modulus of elasticity and strain pattern. Histomorphometrical measurements were performed on toluidine blue tissue sections using a semi-automatic custom-developed MATLAB toolbox. Results suggest that compared to dynamic modulation, static modulation changes the strain pattern of the tissue and thus is more detrimental for tissue biomechanics, while the histomorphological parameters are not affected by mechanical modulation. Also, under dynamic modulation, changing the frequency or amplitude does not affect the biomechanical response of the tissue. Results of this study will be useful in finding optimal and non-damaging parameters

  11. Selective Area Growth of GaAs on Si Patterned Using Nanoimprint Lithography

    SciTech Connect

    Warren, Emily L.; Makoutz, Emily A.; Horowitz, Kelsey A. W.; Dameron, Arrelaine; Norman, Andrew G.; Stradins, Paul; Zimmerman, Jeramy D.; Tamboli, Adele C.

    2016-11-21

    Heteroepitaxial selective area growth (SAG) of GaAs on patterned Si substrates is a potential low-cost approach to integrate III-V and Si materials for tandem or multijunction solar cells. The use of nanoscale openings in a dielectric material can minimize nucleation-related defects and allow thinner buffer layers to be used to accommodate lattice mismatch between Si and an epitaxial III-V layer. For photovoltaic applications, the cost of patterning and growth, as well as the impact on the performance of the Si bottom cell must be considered. We present preliminary results on the use of soft nanoimprint lithography (SNIL) to create patterned nucleation templates for the heteroepitaxial SAG of GaAs on Si. We demonstrate that SNIL patterning of passivating layers on the Si substrate improves measured minority carrier properties relative to unprotected Si. Cost modeling of the SNIL process shows that adding a patterning step only adds a minor contribution to the overall cost of a tandem III-V/Si solar cell, and can enable significant savings if it enables thinner buffer layers.

  12. Size at birth in a rapidly developing economy: intrauterine growth pattern of UAE infants.

    PubMed

    Dawodu, A; Bener, A; Koutouby, G A; Varady, E; Abdulrazzaq, Y

    2008-01-01

    Despite rapid economic growth and the recognition of intrauterine growth pattern as an important indicator of neonatal morbidity and mortality, the size at birth relative to gestation for UAE (United Arab Emirates) live births has not been investigated. The present study evaluated the intrauterine growth pattern of UAE infants and compared the data with the currently used reference standard. A total of 2497 singleton hospital live births to UAE mothers without pregnancy complications were studied. Anthropometric measurements and gestational age assessment of each infant were carried out according to standard procedures. The LMS computer program was used to construct perentile curves. The mean birth weight, length and head circumference of 1113 male term infants were 3298 g, 50.6 cm and 34.5 cm, respectively, and the same parameters for 1118 female term infants were 3201 g, 49.9 cm and 34.0 cm, respectively. These growth parameters were higher in males than females. Mean birth weight data were similar to those reported previously from a study from an economically developed community. The 10th percentile values were higher than in the currently used reference chart. Data on size at birth for UAE infants indicate that continuing use of the current reference chart may underestimate the prevalence of fetal growth failure in the population. Data from larger numbers of very preterm infants are needed to generate percentiles charts for very preterm infants.

  13. Child patterns of growth delay and cognitive development in a Bolivian mining city.

    PubMed

    Ruiz-Castell, María; Carsin, Anne-Elie; Barbieri, Flavia-Laura; Paco, Pamela; Gardon, Jacques; Sunyer, Jordi

    2013-01-01

    This study aims to (1) follow up and characterize infant growth patterns during the first year of life in Bolivia, and (2) determine whether there exists an association between weight gain and cognitive development in children living near contaminated mining industries. Data on 175 children participating to the ToxBol (Toxicity in Bolivia) birth cohort were analyzed. Rapid-growth during the first 6 months was defined as a change in weight z-score > 0.67 while slow-growth was defined as a weight z-score change of < -0.67. Neurodevelopment was evaluated using the Bayley Scales of Infant Development at 10.5-12.5 months of age. Mixed models were used to examine the association between cognitive development and weight gain. Rapid growers weighed less at birth (P < 0.01). However, they revealed a higher body mass index at 12 months of age (0.70 ± 0.73, P < 0.01). After adjustment for confounding, rapid growth was not associated with cognitive development (coef = 0.49, 95% confidence interval = -4.10, 5.08). In this Bolivian cohort, children born smaller were more likely to grow/develop faster and attain greater weight and length. Their cognitive development was not affected by their growth patterns. Copyright © 2012 Wiley Periodicals, Inc.

  14. Biomass allocation and long-term growth patterns of temperate lianas in comparison with trees.

    PubMed

    Ichihashi, Ryuji; Tateno, Masaki

    2015-08-01

    The host-dependent support habit of lianas is generally interpreted as a strategy designed to reduce resource investment in mechanical tissues; this allows preferential allocation to leaf and stem extension, thereby enhancing productivity and competitive abilities. However, this hypothesis has not been rigorously tested. We examined the aboveground allometries regarding biomass allocation (leaf mass and current-year stem mass (approximated as biomass allocated to extension growth) vs total aboveground mass) and long-term apparent growth patterns (height and aboveground mass vs age, i.e. numbers of growth rings) for nine deciduous liana species in Japan. Lianas had, on average, three- and five-fold greater leaf and current-year stem mass, respectively, than trees for a given aboveground mass, whereas the time course to reach the forest canopy was comparable and biomass accumulation during that period was only one-tenth that of co-occurring canopy trees. The balance between the lengths of yearly stem extension and existing older stems indicated that lianas lost c. 75% of stem length during growth to the canopy, which is probably a consequence of the host-dependent growth. Our observations suggest that, although lianas rely on hosts mechanically, allowing for short-term vigorous growth, this habit requires a large cost and could limit plant growth over protracted periods. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  15. Flexible and fixed mathematical models describing growth patterns of chukar partridges

    NASA Astrophysics Data System (ADS)

    Aygün, Ali; Narinç, Doǧan

    2016-04-01

    In animal science, the nonlinear regression models for growth curve analysis ofgrowth patterns are separated into two groups called fixed and flexible according to their point of inflection. The aims of this study were to compare fixed and flexible growth functions and to determine the best fit model for the growth data of chukar partridges. With this aim, the growth data of partridges were modeled with widely used models, such as Gompertz, Logistic, Von Bertalanffy as well as the flexible functions, such as, Richards, Janoschek, Levakovich. So as to evaluate growth functions, the R2 (coefficient of determination), adjusted R2 (adjusted coefficient of determination), MSE (mean square error), AIC (Akaike's information criterion) and BIC (Bayesian information criterion) goodness of fit criteria were used. It has been determined that the best fit model from the point of chukar partridge growth data according to mentioned goodness of fit criteria is Janoschek function which has a flexible structure. The Janoschek model is not only important because it has a higher number of parameters with biological meaning than the other functions (the mature weight and initial weight parameters), but also because it was not previously used in the modeling of the chukar partridge growth.

  16. Self-organized MBE growth of II VI epilayers on patterned GaSb substrates

    NASA Astrophysics Data System (ADS)

    Wissmann, H.; Tran Anh, T.; Rogaschewski, S.; von Ortenberg, M.

    1999-05-01

    We report on the self-organized MBE growth of II-VI epilayers on patterned and unpatterned GaSb substrates resulting in quantum wires and quantum wells, respectively. The HgSe : Fe quantum wires were grown on (0 0 1)GaSb substrates with a buffer of lattice-matched ZnTe 1- xSe x. Due to the anisotropic growth of HgSe on the A-oriented stripes roof-like overgrowth with a definite ridge was obtained. Additional Fe doping in the direct vicinity of the ridge results in a highly conductive quantum wire.

  17. [Spatiotemporal pattern of urban growth and its driving forces in urban agglomeration of central Liaoning Province, China].

    PubMed

    Xi, Feng-Ming; He, Hong-Shi; Hu, Yuan-Man; Wu, Xiao-Qing; Chang, Yu; Liu, Miao; Shi, Tie-Mao; Wang, Jin-Nian

    2010-03-01

    Based on the five temporal Landsat TM remote sensing data of 1988, 1992, 1997, 2000, and 2004, and by using GIS spatial analysis and landscape pattern analysis, this paper analyzed the spatiotemporal pattern of urban growth and its driving forces in the urban agglomeration of central Liaoning Province (UACLP). From 1988 to 2004, the urban area in the UACLP had being increased from 812.55 km2 to 1345.86 km2, with an average growth rate of 32.96 km2 per year. The urban growth rate increased rapidly after 1997, and the urban growth intensity was up to the peak in 1997-2000. The urban growth was mainly concentrated in the central dense belt of the UACLP. From 1988 to 1997, the urban growth was relatively slow, its spatial pattern was compact, and edge growth and filling were the main urban growth types. From 1997 to 2004, the urban growth became faster with diffused spatial pattern and complex patch shape, and "frog leap" and diffusion were the main urban growth types. Non-agricultural population growth, economic growth, urban spatial mutual attraction, industrial development, and development zones construction policies were the main driving forces of urban growth in the UACLP.

  18. Divergence in Patterns of Leaf Growth Polarity Is Associated with the Expression Divergence of miR396

    PubMed Central

    2015-01-01

    Lateral appendages often show allometric growth with a specific growth polarity along the proximo-distal axis. Studies on leaf growth in model plants have identified a basipetal growth direction with the highest growth rate at the proximal end and progressively lower rates toward the distal end. Although the molecular mechanisms governing such a growth pattern have been studied recently, variation in leaf growth polarity and, therefore, its evolutionary origin remain unknown. By surveying 75 eudicot species, here we report that leaf growth polarity is divergent. Leaf growth in the proximo-distal axis is polar, with more growth arising from either the proximal or the distal end; dispersed with no apparent polarity; or bidirectional, with more growth contributed by the central region and less growth at either end. We further demonstrate that the expression gradient of the miR396-GROWTH-REGULATING FACTOR module strongly correlates with the polarity of leaf growth. Altering the endogenous pattern of miR396 expression in transgenic Arabidopsis thaliana leaves only partially modified the spatial pattern of cell expansion, suggesting that the diverse growth polarities might have evolved via concerted changes in multiple gene regulatory networks. PMID:26410303

  19. Growth Pattern in Paediatric Crohn Disease Is Related to Inflammatory Status.

    PubMed

    Ley, Delphine; Duhamel, Alain; Behal, Hélène; Vasseur, Francis; Sarter, Hélène; Michaud, Laurent; Gower-Rousseau, Corinne; Turck, Dominique

    2016-12-01

    The respective role of disease activity and steroid therapy in growth impairment in paediatric-onset Crohn disease (CD) is still debated. Our aim was to investigate whether the growth pattern of children with CD was correlated with the inflammatory status during the disease course, regardless the cumulative duration of steroid therapy. One hundred and seven patients with a diagnosis of CD <17 years, followed during ≥2 years and for whom ≥2 height measures were available during follow-up, were identified between 1998 and 2010. Height, C-reactive protein (CRP), orosomucoid, and steroid therapy duration were collected at each visit. The relationship between the evolution of growth velocity and inflammatory status during follow-up was investigated using a linear mixed model with random coefficients. Median age at diagnosis was 11.7 years (Q1-Q3: 9.8-13.5). Mean height for age (H/A) z score was 0.14 ± 1.29 at diagnosis and 0.05 ± 1.23 among the 75 patients who had reached their final height at maximal follow-up (median: 4.9 years; Q1-Q3: 3.8-6.4). Growth failure (H/A z score <-2) was present in 7 (8%) patients at diagnosis and 5 (5%) at maximal follow-up. Growth velocity was negatively correlated with the evolution of CRP (P < 0.0001) and orosomucoid (P < 0.0001) during follow-up. After adjustment for the cumulative duration of steroid therapy, these 2 correlations remained significant (CRP: P = 0.0008; orosomucoid: P < 0.0001). Children with CD with uncontrolled inflammatory status have a lower growth velocity. The inflammatory status should be kept as close to normal as possible in paediatric-onset patients with CD to optimize their growth pattern.

  20. Bladder tumours in children: An interesting case report of TCC with a partial inverted growth pattern.

    PubMed

    El Rahman, Davide Abed; Salvo, Giuseppe; Palumbo, Carlotta; Rocco, Bernardo; Rocco, Francesco

    2014-09-30

    Bladder urothelial carcinoma is typically a disease of older individuals and rarely occurs below the age of 40 years. There is debate and uncertainty in the literature regarding the clinicopathologic and prognostic characteristics of bladder urothelial neoplasms in younger patients compared with older patients, although no consistent age criteria have been used to define "younger" age group categories. We report on a 16 years old girl with transitional cell carcinoma of the bladder with a partial inverted growth pattern who presented with gross hematuria. Ultrasonography revealed a papillary lesion in the bladder; cystoscopic evaluation showed a 15 mm papillary lesion with a thick stalk located in the left bladder wall. Pathologic evaluation of the specimen was reported as "low grade transitional cell carcinoma of the bladder with a partial inverted growth pattern".

  1. Connecting the Dots between PubMed Abstracts

    PubMed Central

    Hossain, M. Shahriar; Gresock, Joseph; Edmonds, Yvette; Helm, Richard; Potts, Malcolm; Ramakrishnan, Naren

    2012-01-01

    Background There are now a multitude of articles published in a diversity of journals providing information about genes, proteins, pathways, and diseases. Each article investigates subsets of a biological process, but to gain insight into the functioning of a system as a whole, we must integrate information from multiple publications. Particularly, unraveling relationships between extra-cellular inputs and downstream molecular response mechanisms requires integrating conclusions from diverse publications. Methodology We present an automated approach to biological knowledge discovery from PubMed abstracts, suitable for “connecting the dots” across the literature. We describe a storytelling algorithm that, given a start and end publication, typically with little or no overlap in content, identifies a chain of intermediate publications from one to the other, such that neighboring publications have significant content similarity. The quality of discovered stories is measured using local criteria such as the size of supporting neighborhoods for each link and the strength of individual links connecting publications, as well as global metrics of dispersion. To ensure that the story stays coherent as it meanders from one publication to another, we demonstrate the design of novel coherence and overlap filters for use as post-processing steps. Conclusions We demonstrate the application of our storytelling algorithm to three case studies: i) a many-one study exploring relationships between multiple cellular inputs and a molecule responsible for cell-fate decisions, ii) a many-many study exploring the relationships between multiple cytokines and multiple downstream transcription factors, and iii) a one-to-one study to showcase the ability to recover a cancer related association, viz. the Warburg effect, from past literature. The storytelling pipeline helps narrow down a scientist's focus from several hundreds of thousands of relevant documents to only around a hundred

  2. Non-equilibrium growth patterns of carbohydrate and saccharin in gel media

    NASA Astrophysics Data System (ADS)

    Das, Ishwar; Sharma, Archana; Kumar, Anuj; Lall, R. S.

    1997-02-01

    Non-equilibrium growth patterns of mono-, di-saccharides and a sweetener saccharin have been developed on microslides in the presence of a dense matrix. Scanned pictures were analyzed and fractal dimensions calculated by a box counting method. Morphologies and fractal dimension were found to depend on the compound-dense matrix composition. In case of di-saccharides, the morphology depends on a linkage between the monomer units.

  3. GeneView: a comprehensive semantic search engine for PubMed.

    PubMed

    Thomas, Philippe; Starlinger, Johannes; Vowinkel, Alexander; Arzt, Sebastian; Leser, Ulf

    2012-07-01

    Research results are primarily published in scientific literature and curation efforts cannot keep up with the rapid growth of published literature. The plethora of knowledge remains hidden in large text repositories like MEDLINE. Consequently, life scientists have to spend a great amount of time searching for specific information. The enormous ambiguity among most names of biomedical objects such as genes, chemicals and diseases often produces too large and unspecific search results. We present GeneView, a semantic search engine for biomedical knowledge. GeneView is built upon a comprehensively annotated version of PubMed abstracts and openly available PubMed Central full texts. This semi-structured representation of biomedical texts enables a number of features extending classical search engines. For instance, users may search for entities using unique database identifiers or they may rank documents by the number of specific mentions they contain. Annotation is performed by a multitude of state-of-the-art text-mining tools for recognizing mentions from 10 entity classes and for identifying protein-protein interactions. GeneView currently contains annotations for >194 million entities from 10 classes for ∼21 million citations with 271,000 full text bodies. GeneView can be searched at http://bc3.informatik.hu-berlin.de/.

  4. History and Trends of "Personal Health Record" Research in PubMed

    PubMed Central

    Kim, Jeongeun; Bates, David W.

    2011-01-01

    Objectives The purpose of this study was to review history and trends of personal health record research in PubMed and to provide accurate understanding and categorical analysis of expert opinions. Methods For the search strategy, PubMed was queried for 'personal health record, personal record, and PHR' in the title and abstract fields. Those containing different definitions of the word were removed by one-by-one analysis from the results, 695 articles. In the end, total of 229 articles were analyzed in this research. Results The results show that the changes in terms over the years and the shift to patient centeredness and mixed usage. And we identified history and trend of PHR research in some category that the number of publications by year, topic, methodologies and target diseases. Also from analysis of MeSH terms, we can show the focal interest in regards the PHR boundaries and related subjects. Conclusions For PHRs to be efficiently used by general public, initial understanding of the history and trends of PHR research may be helpful. Simultaneously, accurate understanding and categorical analysis of expert opinions that can lead to the development and growth of PHRs will be valuable to their adoption and expansion. PMID:21818452

  5. GeneView: a comprehensive semantic search engine for PubMed

    PubMed Central

    Thomas, Philippe; Starlinger, Johannes; Vowinkel, Alexander; Arzt, Sebastian; Leser, Ulf

    2012-01-01

    Research results are primarily published in scientific literature and curation efforts cannot keep up with the rapid growth of published literature. The plethora of knowledge remains hidden in large text repositories like MEDLINE. Consequently, life scientists have to spend a great amount of time searching for specific information. The enormous ambiguity among most names of biomedical objects such as genes, chemicals and diseases often produces too large and unspecific search results. We present GeneView, a semantic search engine for biomedical knowledge. GeneView is built upon a comprehensively annotated version of PubMed abstracts and openly available PubMed Central full texts. This semi-structured representation of biomedical texts enables a number of features extending classical search engines. For instance, users may search for entities using unique database identifiers or they may rank documents by the number of specific mentions they contain. Annotation is performed by a multitude of state-of-the-art text-mining tools for recognizing mentions from 10 entity classes and for identifying protein–protein interactions. GeneView currently contains annotations for >194 million entities from 10 classes for ∼21 million citations with 271 000 full text bodies. GeneView can be searched at http://bc3.informatik.hu-berlin.de/. PMID:22693219

  6. Relationship between growth and the pattern of tooth initiation in alligator embryos.

    PubMed

    Osborn, J W

    1998-09-01

    The temporal and spatial patterns in which teeth are initiated in the growing jaws of embryos are constant for a species but different for different species. The sources of the patterns have been explained in two ways. First, they are the outcome of reactions between molecules created at stationary targets and those which diffuse through embryonic tissues (e.g., Edmund, 1960). Second, Osborn (1978) supposed that the patterns mirror the way a (mixed) population of parent cells, the tooth clone, grows. Westergaard and Ferguson (1986, 1987, 1990) concluded, from their observations of the sequence of tooth initiation in alligators, that the complicated sequences in which 20 teeth are initiated in each tooth quadrant could not be explained by jaw growth. The present study attempts to refute this criticism by means of measurements made from the raw data published by Westergaard and Ferguson. These data reveal that new teeth, here called primary teeth, are added at a constant rate at the back of the jaw. Interstitial growth of the cells between primary teeth creates space for secondary teeth in secondary regions. The secondary regions increase in length exponentially with time. The sequence in which teeth are initiated in the growing secondary regions was found to be the same in every part of the upper and lower jaws. It was accurately reproduced by a computer program based on a linear contraction rate of inhibitory zones and exponential growth of secondary regions. The results suggest that the posterior progress zone in alligator embryos grows about 125 microm a day. Newly initiated tooth germs are surrounded by an inhibitory zone about 250 microm in diameter. These zones contract from 20 to 30 microm a day until they are about 170 microm in diameter. The sequences in which tooth positions are initiated in embryos may be more the result of the pattern in which cells escape from molecules that inhibit induction rather than the pattern in which cells create molecules that

  7. Disproportionate growth between the spine and pelvis in patients with thoracic adolescent scoliosis: a new look into the pattern's growth.

    PubMed

    Bao, H; Liu, Z; Yan, P; Qiu, Y; Zhu, F

    2015-12-01

    A self-control ratio, the spine-pelvis index (SPI), was proposed for the assessment of patients with adolescent idiopathic scoliosis (AIS) in this study. The aim was to evaluate the disproportionate growth between the spine and pelvis in these patients using SPI. A total of 64 female patients with thoracic AIS were randomly enrolled between December 2010 and October 2012 (mean age 13 years, standard deviation (sd) 2.17; 9 to 18) and a further 73 healthy female patients with a mean age of 12.4 years (mean age 12.4 years, sd 2.24; 9 to 18), were randomly selected from a normal control database at our centre. The radiographic parameters measured included length of spine (LOS), height of spine (HOS), length of thoracic vertebrae (LOT), height of thoracic vertebrae (HOT), width of pelvis (WOP), height of pelvis (HOP) and width of thorax (WOT). SPI was defined as the ratio LOS/HOP. The SPI and LOT/HOP in patients with AIS showed a significant increase when compared with normal girls (p < 0.001 and p < 0.001 respectively), implying an abnormal pattern of growth of the spine relative to the pelvis in patients with AIS. No significant difference in SPI was found in different age groups in the control group, making the SPI an age-independent parameter with a mean value of 2.219 (2.164 to 2.239). We also found that the SPI was not related to maturity in the control group. This study, for the first time, used a self-control ratio to confirm the disproportionate patterns of growth of the spine and pelvis in patients with thoracic AIS, highlighting that the SPI is not affected by age or maturity.

  8. Disentangling the climate-driven bimodal growth pattern in coastal and continental Mediterranean pine stands.

    PubMed

    Pacheco, Arturo; Camarero, J Julio; Ribas, Montse; Gazol, Antonio; Gutierrez, E; Carrer, Marco

    2017-09-16

    Mediterranean climate promotes two distinct growth peaks separated by summer quiescence in trees. This bimodal pattern has been associated to favourable growing conditions during spring and autumn when mild temperatures and soil-water availability enhance cambial activity. Climatic models predict progressive warming and drying for the Mediterranean Basin, which could shorten or shift the spring and autumn growing seasons. We explored this idea by comparing two sites with different Mediterranean climate types (continental/dry and coastal/wet) and studied how climate drives the bimodal growth pattern in Aleppo pine (Pinus halepensis). Specifically we investigated the intra-annual changes in wood anatomy and the corresponding formation of density fluctuations (IADF). Trees on both sites were analyzed by dendrometer monitoring and by developing chronologies of wood anatomical traits. Radial-increment dynamics followed a similar bimodal pattern in both sites but coastal trees showed higher increments during the spring and autumn growth peaks, especially in autumn. The summer rest of cambium activity occurs almost one month earlier in the coastal than in the inland site. Lumen area and cell-wall thickness were significantly smaller in the continental site, while the increment rate of cell-wall thickness during an IADF event was much higher in the coastal pines. The accumulated soil moisture deficit was the main climatic constraint of tracheid enlargement in continental pines. Intra-annual density fluctuations were more frequent in the coastal trees where wood anatomy features recover to average values after such events, meanwhile inland trees presented a much lower recovery rate. Growth bimodality and the formation of density fluctuations were linked, but mild climate of the coastal site allows a longer growing season, which explains why trees in this area showed higher and more variable growth rates. Copyright © 2017. Published by Elsevier B.V.

  9. Tree growth rates in an Amazonian evergreen forest: seasonal patterns and correlations with leaf phenology

    NASA Astrophysics Data System (ADS)

    Wu, J.; Silva Campos, K.; Prohaska, N.; Ferreira, M. L.; Nelson, B. W.; Saleska, S. R.; da Silva, R.

    2014-12-01

    Metabolism and phenology of tropical forests significantly influence global dynamics of climate, carbon and water. However, there is still lack of mechanistic understanding of the controls on tropical forest metabolism, particularly at individual tree level. In this study, we are interested in investigating (1) what is the seasonal pattern of woody growth for tropical trees and (2) what is the mechanistic controls onwoody growth at individual level?To explore the above questions,we use two data sources from an evergreen tropical forest KM67 site (near Santarem, Brazil). They are: (1) image time series from a tower mounted RGB imaging system, with images recordedin10 minutes interval since October 2013.Images near local noon homogeneous diffuse lighting were selectedfor leaf phenologymonitoring; (2) ground based bi-weekly biometry survey (via dendrometry band technique) for 25 trees from random sampling since September 2013. 12 among 25 trees are within the tower mounted camera image view. Our preliminary resultsdemonstrate that 20 trees among 25 trees surveyed significantly increase woody growth (or "green up") in dry season. Our results also find thatamong those 20 trees, 12 trees reaches the maximum woody increment rate in late dry season with a mean DBH (Diameter at Breast Height) around 30 cm,while 8 trees reaching the maximum in the middle of wet season, with a mean DBH around 90 cm. This study,though limited in the sample size, mightprovide another line of evidence that Amazon rainforests "green up" in dry season. As for mechanistic controls on tropical tree woody control, we hypothesize both climate and leaf phenology control individual woody growth. We would like to link both camera based leaf phenology and climate data in the next to explorethe reason as to the pattern found in this study that bigger trees might have different seasonal growth pattern as smaller trees.

  10. A fractal growth model: Exploring the connection pattern of hubs in complex networks

    NASA Astrophysics Data System (ADS)

    Li, Dongyan; Wang, Xingyuan; Huang, Penghe

    2017-04-01

    Fractal is ubiquitous in many real-world networks. Previous researches showed that the strong disassortativity between the hub-nodes on all length scales was the key principle that gave rise to the fractal architecture of networks. Although fractal property emerged in some models, there were few researches about the fractal growth model and quantitative analyses about the strength of the disassortativity for fractal model. In this paper, we proposed a novel inverse renormalization method, named Box-based Preferential Attachment (BPA), to build the fractal growth models in which the Preferential Attachment was performed at box level. The proposed models provided a new framework that demonstrated small-world-fractal transition. Also, we firstly demonstrated the statistical characteristic of connection patterns of the hubs in fractal networks. The experimental results showed that, given proper growing scale and added edges, the proposed models could clearly show pure small-world or pure fractal or both of them. It also showed that the hub connection ratio showed normal distribution in many real-world networks. At last, the comparisons of connection pattern between the proposed models and the biological and technical networks were performed. The results gave useful reference for exploring the growth principle and for modeling the connection patterns for real-world networks.

  11. High Field Emission Current Density from Patterned Carbon Nanotube Field Emitter Arrays with Random Growth.

    PubMed

    Khaneja, Mamta; Ghosh, Santanu; Gautam, Seema; Kumar, Prashant; Rawat, J S; Chaudhury, P K; Vankar, V D; Kumar, Vikram

    2015-05-01

    High field emission (FE) current density from carbon nanotube (CNT) arrays grown on lithographically patterned silicon substrates is reported. A typical patterned field emitter array consists of bundles of nanotubes separated by a fixed gap and spread over the entire emission area. Emission performance from such an array having randomly oriented nanotube growth within each bundle is reported for different bundle sizes and separations. One typical sample with aligned CNTs within the bundle is also examined for comparison. It is seen that the current density from an array having random nanotube growth within the bundles is appreciably higher as compared to its aligned counterpart. The influence of structure on FE current densities as revealed by Raman spectroscopy is also seen. It is also observed that current density depends on edge length and increases with the same for all samples under study. Highest current density of -100 mA cm(-2) at an applied field of 5 V/μm is achieved from the random growth patterned sample with a bundle size of 2 μm and spacing of 4 μm between the bundles.

  12. [Age structure and growth pattern of Polytrichum juniperum populations in a mire of Changbai Mountains].

    PubMed

    Bu, Zhaojun; Yan, Yunfei; Dai, Dan; Wang, Xianwei

    2005-01-01

    In this paper, the age structure and growth pattern of two Polytrichum juniperum populations with and without sporophytes in Hani mire of Changbai Mountains were studied by 'innate annual marker' method. The ramets of both populations were composed of 6 age classes, and their quantity and biomass showed a declining age structure, which was more obvious in the sporophyte produced population. No significant difference of biomass was found (P > 0.05) between the two populations. The dry material accumulation of the ramets in both populations increased with aging, and showed similar patterns of linear function. The ramets mean height of sporophyte-produced population was 6.17% shorter (P < 0.05) than the another, because sporophyte production limited the height growth. The ramets mean height also increased with aging, and showed similar patterns of linear function. In non-sporophyte produced population, the variation coefficient of ramets height was only 2.44%, which indicated the significance of similar height for ramets survival. In sporophyte produced population, the variation coefficient of ramets height was 25.07%, while that of ramets biomass was 8.25%, suggesting the significance of similar biomass to the reproduction of population. The biomass of ramets had a significantly positive correlation with height in both populations (P < 0.001), and no allometric growth was showed.

  13. Growth patterns in Onychophora (velvet worms): lack of a localised posterior proliferation zone

    PubMed Central

    2010-01-01

    Background During embryonic development of segmented animals, body segments are thought to arise from the so-called "posterior growth zone" and the occurrence of this "zone" has been used to support the homology of segmentation between arthropods, annelids, and vertebrates. However, the term "posterior growth zone" is used ambiguously in the literature, mostly referring to a region of increased proliferation at the posterior end of the embryo. To determine whether such a localised posterior proliferation zone is an ancestral feature of Panarthropoda (Onychophora + Tardigrada + Arthropoda), we examined cell division patterns in embryos of Onychophora. Results Using in vivo incorporation of the DNA replication marker BrdU (5-bromo-2'-deoxyuridine) and anti-phospho-histone H3 immunolabelling, we found that a localised posterior region of proliferating cells does not occur at any developmental stage in onychophoran embryos. This contrasts with a localised pattern of cell divisions at the posterior end of annelid embryos, which we used as a positive control. Based on our data, we present a mathematical model, which challenges the paradigm that a localised posterior proliferation zone is necessary for segment patterning in short germ developing arthropods. Conclusions Our findings suggest that a posterior proliferation zone was absent in the last common ancestor of Onychophora and Arthropoda. By comparing our data from Onychophora with those from annelids, arthropods, and chordates, we suggest that the occurrence of a "posterior growth zone" currently cannot be used to support the homology of segmentation between these three animal groups. PMID:21050428

  14. Growth patterns in Onychophora (velvet worms): lack of a localised posterior proliferation zone.

    PubMed

    Mayer, Georg; Kato, Chiharu; Quast, Björn; Chisholm, Rebecca H; Landman, Kerry A; Quinn, Leonie M

    2010-11-04

    During embryonic development of segmented animals, body segments are thought to arise from the so-called "posterior growth zone" and the occurrence of this "zone" has been used to support the homology of segmentation between arthropods, annelids, and vertebrates. However, the term "posterior growth zone" is used ambiguously in the literature, mostly referring to a region of increased proliferation at the posterior end of the embryo. To determine whether such a localised posterior proliferation zone is an ancestral feature of Panarthropoda (Onychophora + Tardigrada + Arthropoda), we examined cell division patterns in embryos of Onychophora. Using in vivo incorporation of the DNA replication marker BrdU (5-bromo-2'-deoxyuridine) and anti-phospho-histone H3 immunolabelling, we found that a localised posterior region of proliferating cells does not occur at any developmental stage in onychophoran embryos. This contrasts with a localised pattern of cell divisions at the posterior end of annelid embryos, which we used as a positive control. Based on our data, we present a mathematical model, which challenges the paradigm that a localised posterior proliferation zone is necessary for segment patterning in short germ developing arthropods. Our findings suggest that a posterior proliferation zone was absent in the last common ancestor of Onychophora and Arthropoda. By comparing our data from Onychophora with those from annelids, arthropods, and chordates, we suggest that the occurrence of a "posterior growth zone" currently cannot be used to support the homology of segmentation between these three animal groups.

  15. Experimental investigation of the dynamics of spontaneous pattern formation during dendritic ice crystal growth

    NASA Astrophysics Data System (ADS)

    Tirmizi, Shakeel H.; Gill, William N.

    1989-06-01

    The dynamics of spontaneous pattern formation are studied experimentally by observing and recording the evolution of ice crystal patterns which grow freely in a supercooled melt. The sequence of evolution to dendrites is recorded in real time using cine-micrography. In the range of subcoolings from 0.06 to 0.29°C, all the patterns evolved as follows: Smooth disk → Perturbed disk → Disk dendrite → Partially developed dendrite → Fully developed dendrite. The initial smooth disk, the main branch and the side branches all developed perturbations beyond a critical size which depends on the subcooling. The combined effect of the destabilizing thermal gradients ahead of the growing crystal and the stabilizing Gibbs-Thompson capillarity effect dictates the critical size of the unstable structures in terms of the mean curvature of the interface. Detailed analysis of the evolving patterns was done using digital image analysis on the PRIME computer to determine both the manner in which the dendritic growth process replicates itself and the role which the shape and the movement of the interface play in the pattern formation process. Total arc length ST, total area A and the complexity ratio ξ = ST⧸√ A of evolving patterns were computed as a function of time and undercooling for each crystal image. These results permitted us to make some comparisons with theoretical models on pattern evolution. Three distinct phases of evolution were identified: the initial phase when the crystal structure is smooth and free of any perturbations and the complexity ratio is almost a constant, an intermediate phase when the crystal structure develops perturbations which grow quickly in number and in size and the complexity ratio increases rapidly and a final phase when the pattern approaches that of a fully developed dendrite which, on a global scale grows in a shape-perserving manner and has a slowly increasing complexity ratio which seems to approach an asymptote. Two factors were

  16. Digital Transfer Growth of Patterned 2D Metal Chalcogenides by Confined Nanoparticle Evaporation

    SciTech Connect

    Mahjouri-Samani, Masoud; Tian, Mengkun; Wang, Kai; Boulesbaa, Abdelaziz; Rouleau, Christopher M.; Puretzky, Alexander A.; McGuire, Michael A.; Srijanto, Bernadeta R.; Xiao, Kai; Eres, Gyula; Duscher, Gerd; Geohegan, David B.

    2014-10-19

    Developing methods for the facile synthesis of two-dimensional (2D) metal chalcogenides and other layered materials is crucial for emerging applications in functional devices. Controlling the stoichiometry, number of the layers, crystallite size, growth location, and areal uniformity is challenging in conventional vapor phase synthesis. Here, we demonstrate a new route to control these parameters in the growth of metal chalcogenide (GaSe) and dichalcogenide (MoSe2) 2D crystals by precisely defining the mass and location of the source materials in a confined transfer growth system. A uniform and precise amount of stoichiometric nanoparticles are first synthesized and deposited onto a substrate by pulsed laser deposition (PLD) at room temperature. This source substrate is then covered with a receiver substrate to form a confined vapor transport growth (VTG) system. By simply heating the source substrate in an inert background gas, a natural temperature gradient is formed that evaporates the confined nanoparticles to grow large, crystalline 2D nanosheets on the cooler receiver substrate, the temperature of which is controlled by the background gas pressure. Large monolayer crystalline domains (~ 100 m lateral sizes) of GaSe and MoSe2 are demonstrated, as well as continuous monolayer films through the deposition of additional precursor materials. This novel PLD-VTG synthesis and processing method offers a unique approach for the controlled growth of large-area, metal chalcogenides with a controlled number of layers in patterned growth locations for optoelectronics and energy related applications.

  17. Prediction of competitive microbial growth in mixed culture at dynamic temperature patterns.

    PubMed

    Fujikawa, Hiroshi; Sakha, Mohammad Z

    2014-01-01

    A novel competition model developed with the new logistic model and the Lotka-Volterra model successfully predicted the growth of bacteria in mixed culture using the mesophiles Staphylococcus aureus, Escherichia coli, and Salmonella at a constant temperature in our previous studies. In this study, we further studied the prediction of the growth of those bacteria in mixed culture at dynamic temperatures with various initial populations with the competition model. First, we studied the growth kinetics of the species in a monoculture at various constant temperatures ranging from 16℃ to 32℃. With the analyzed data in the monoculture, we then examined the prediction of bacterial growth in mixed culture with two and three species. The growth of the bacteria in the mixed culture at dynamic temperatures was successfully predicted with the model. The residuals between the observed and predicted populations at the data points were <0.5 log at most points, being 83.3% and 84.2% for the two-species mixture and the three-species mixture, respectively. The present study showed that the model could be applied to the competitive growth in mixed culture at dynamic temperature patterns.

  18. Human growth is associated with distinct patterns of gene expression in evolutionarily conserved networks

    PubMed Central

    2013-01-01

    Background A co-ordinated tissue-independent gene expression profile associated with growth is present in rodent models and this is hypothesised to extend to all mammals. Growth in humans has similarities to other mammals but the return to active long bone growth in the pubertal growth spurt is a distinctly human growth event. The aim of this study was to describe gene expression and biological pathways associated with stages of growth in children and to assess tissue-independent expression patterns in relation to human growth. Results We conducted gene expression analysis on a library of datasets from normal children with age annotation, collated from the NCBI Gene Expression Omnibus (GEO) and EBI Arrayexpress databases. A primary data set was generated using cells of lymphoid origin from normal children; the expression of 688 genes (ANOVA false discovery rate modified p-value, q < 0.1) was associated with age, and subsets of these genes formed clusters that correlated with the phases of growth – infancy, childhood, puberty and final height. Network analysis on these clusters identified evolutionarily conserved growth pathways (NOTCH, VEGF, TGFB, WNT and glucocorticoid receptor – Hyper-geometric test, q < 0.05). The greatest degree of network ‘connectivity’ and hence functional significance was present in infancy (Wilcoxon test, p < 0.05), which then decreased through to adulthood. These observations were confirmed in a separate validation data set from lymphoid tissue. Similar biological pathways were observed to be associated with development-related gene expression in other tissues (conjunctival epithelia, temporal lobe brain tissue and bone marrow) suggesting the existence of a tissue-independent genetic program for human growth and maturation. Conclusions Similar evolutionarily conserved pathways have been associated with gene expression and child growth in multiple tissues. These expression profiles associate with the developmental phases

  19. Trophic interactions and population growth rates: describing patterns and identifying mechanisms.

    PubMed Central

    Hudson, Peter J; Dobson, Andy P; Cattadori, Isabella M; Newborn, David; Haydon, Dan T; Shaw, Darren J; Benton, Tim G; Grenfell, Bryan T

    2002-01-01

    While the concept of population growth rate has been of central importance in the development of the theory of population dynamics, few empirical studies consider the intrinsic growth rate in detail, let alone how it may vary within and between populations of the same species. In an attempt to link theory with data we take two approaches. First, we address the question 'what growth rate patterns does theory predict we should see in time-series?' The models make a number of predictions, which in general are supported by a comparative study between time-series of harvesting data from 352 red grouse populations. Variations in growth rate between grouse populations were associated with factors that reflected the quality and availability of the main food plant of the grouse. However, while these results support predictions from theory, they provide no clear insight into the mechanisms influencing reductions in population growth rate and regulation. In the second part of the paper, we consider the results of experiments, first at the individual level and then at the population level, to identify the important mechanisms influencing changes in individual productivity and population growth rate. The parasitic nematode Trichostrongylus tenuis is found to have an important influence on productivity, and when incorporated into models with their patterns of distribution between individuals has a destabilizing effect and generates negative growth rates. The hypothesis that negative growth rates at the population level were caused by parasites was demonstrated by a replicated population level experiment. With a sound and tested model framework we then explore the interaction with other natural enemies and show that in general they tend to stabilize variations in growth rate. Interestingly, the models show selective predators that remove heavily infected individuals can release the grouse from parasite-induced regulation and allow equilibrium populations to rise. By contrast, a

  20. Sagittal maxillary growth pattern in unilateral cleft lip and palate patients with unrepaired cleft palate.

    PubMed

    Chen, Zhen-Qi; Wu, Jun; Chen, Rong-Jing

    2012-03-01

    The objective of the study was to examine the sagittal maxillary growth pattern during the mixed and permanent dentition in unilateral cleft lip and palate (UCLP) patients with unrepaired cleft palate. A total of 30 nonsyndromic UCLP patients with unrepaired cleft palate were included, 15 of whom were in mixed dentition and 15 in permanent dentition.Cephalograms were analyzed and compared in the patients with UCLP who have operatively undergone repair with both the lip and palate as well as normal subjects. The UCLP patients with unrepaired cleft palate in mixed dentition showed decreased anterior-posterior length of the maxilla. The UCLP patients with unrepaired cleft palate in permanent dentition demonstrated an almost normal maxillary growth. The operated-on patients both in mixed and permanent dentitions showed maxillary retrusion as well as decreased maxillary length. There appears that there may be the potential normal maxillary growth in UCLP patients, and early surgical repair of the cleft palate may affect sagittal maxillary growth pattern in patients with cleft.

  1. Uncoupling dendrite growth and patterning: single-cell knockout analysis of NMDA receptor 2B.

    PubMed

    Espinosa, J Sebastian; Wheeler, Damian G; Tsien, Richard W; Luo, Liqun

    2009-04-30

    N-methyl-D-aspartate receptors (NMDARs) play important functions in neural development. NR2B is the predominant NR2 subunit of NMDAR in the developing brain. Here we use mosaic analysis with double markers (MADM) to knock out NR2B in isolated single cells and analyze its cell-autonomous function in dendrite development. NR2B mutant dentate gyrus granule cells (dGCs) and barrel cortex layer 4 spiny stellate cells (bSCs) have similar dendritic growth rates, total length, and branch number as control cells. However, mutant dGCs maintain supernumerary primary dendrites resulting from a pruning defect. Furthermore, while control bSCs restrict dendritic growth to a single barrel, mutant bSCs maintain dendritic growth in multiple barrels. Thus, NR2B functions cell autonomously to regulate dendrite patterning to ensure that sensory information is properly represented in the cortex. Our study also indicates that molecular mechanisms that regulate activity-dependent dendrite patterning can be separated from those that control general dendrite growth and branching.

  2. Maternal and paternal height and BMI and patterns of fetal growth: the Pune Maternal Nutrition Study.

    PubMed

    Wills, Andrew K; Chinchwadkar, Manoj C; Joglekar, Charudatta V; Natekar, Asit S; Yajnik, Chittaranjan S; Fall, Caroline H D; Kinare, Arun S

    2010-09-01

    We examined the differential associations of each parent's height and BMI with fetal growth, and examined the pattern of the associations through gestation. Data are from 557 term pregnancies in the Pune Maternal Nutrition Study. Size and conditional growth outcomes from 17 to 29 weeks to birth were derived from ultrasound and birth measures of head circumference, abdominal circumference, femur length and placental volume (at 17 weeks only). Parental height was positively associated with fetal head circumference and femur length. The associations with paternal height were detectible earlier in gestation (17-29 weeks) compared to the associations with maternal height. Fetuses of mothers with a higher BMI had a smaller mean head circumference at 17 weeks, but caught up to have larger head circumference at birth. Maternal but not paternal BMI, and paternal but not maternal height, were positively associated with placental volume. The opposing associations of placenta and fetal head growth with maternal BMI at 17 weeks could indicate prioritisation of early placental development, possibly as a strategy to facilitate growth in late gestation. This study has highlighted how the pattern of parental-fetal associations varies over gestation. Further follow-up will determine whether and how these variations in fetal/placental development relate to health in later life.

  3. Uncoupling Dendrite Growth and Patterning: Single Cell Knockout Analysis of NMDA Receptor 2B

    PubMed Central

    Espinosa, J. Sebastian; Wheeler, Damian G.; Tsien, Richard W.; Luo, Liqun

    2009-01-01

    SUMMARY N-Methyl-D-aspartate receptors (NMDARs) play important functions in neural development. NR2B is the predominant NR2 subunit of NMDAR in the developing brain. Here we use MADM (Mosaic Analysis with Double Markers) to knock out NR2B in isolated single cells and analyze its cell-autonomous function in dendrite development. NR2B mutant dentate gyrus granule cells (dGCs) and barrel cortex layer 4 spiny stellate cells (bSCs) have similar dendritic growth rates, total length and branch number as control cells. However, mutant dGCs maintain supernumerary primary dendrites resulting from a pruning defect. Furthermore, while control bSCs restrict dendritic growth to a single barrel, mutant bSCs maintain dendritic growth in multiple barrels. Thus, NR2B functions cell-autonomously to regulate dendrite patterning to ensure that sensory information is properly represented in the cortex. Our study also indicates that molecular mechanisms that regulate activity-dependent dendrite patterning can be separated from those that control general dendrite growth and branching. PMID:19409266

  4. Modification by Ethylene of the Cell Growth Pattern in Different Tissues of Etiolated Lupine Hypocotyls 1

    PubMed Central

    Sánchez-Bravo, José; Ortuño, Ana M.; Pérez-Gilabert, Manuela; Acosta, Manuel; Sabater, Francisco

    1992-01-01

    The influence of ethylene on growth in etiolated lupine (Lupinus albus L.) hypocotyls was studied in ethephon-treated plants. Ethephon reduced the length and increased the diameter of hypocotyls. At the end of the hypocotyl growth period (14 days), the fresh weight was reduced by 53%, and the dry weight was reduced by 16%. Thus, ethylene reduced water uptake in the tissues to a greater extent than the incorporation of new materials. Light microscopic measurements showed that the thickness of tissues was stimulated by ethylene, the vascular cylinder and cortex exhibiting greater increases (55 and 45%, respectively) than pith (26%) or epidermis (12%). Ethephon modified the cell growth pattern, stimulating lateral cell expansion and cell wall thickness, while reducing cell elongation. The response to ethylene varied in the different tissues and was higher in cortex and pith cells than in the epidermis cells. The ethylene-induced cell expansion in the cortex varied according to the localization of cells in the tissue: the central and subepidermal layers showed little change, whereas the innermost layers exhibited the greatest increase. Electron microscopy revealed that ethylene increased both the rough endoplasmic reticulum and dictyosomes, suggesting that ethylene stimulated the secretion of cell wall materials. In untreated seedlings, the pattern of cell growth was similar in cells from the epidermis, cortex, and pith. The final cell size varied along the hypocotyl, the cells becoming shorter and broader the closer to the basal zones of the organ. ImagesFigure 1Figure 5 PMID:16668735

  5. Stochastic modeling of the tumor volume assessment and growth patterns in hepatocellular carcinoma.

    PubMed

    Sãftoiu, Adrian; Ciurea, Tudorel; Gorunescu, Florin; Rogoveanu, Ion; Georgescu, Claudia

    2004-06-01

    The growth pattern of hepatocellular carcinoma (HCC) arising from cirrhosis is variable and depends on the degree of differentiation and vascularization. Because growth is not constant in the natural history of HCC, prediction of subsequent growth rate based on tumor volume doubling time and correlation with histological and ultrasonographical characteristics at the moment of initial diagnosis are usually unreliable. The aim of our study was to assess the growth patterns of HCC with the aid of stochastic modeling. Thus, we included in our study 27 patients with histologically proven HCC, which had multiple (more than three)follow-up ultrasound studies in a six months interval. The patients did not receive any treatment during the observation period. HCC was visualized by computer aided ultrasound imaging, obtaining both the primary size quantification and the edge-detection enhancement. By a bi-cubic B-spline interpolation of points on the edges (3-D Bezier approximation) we approximated the surfaces shapes, and using the hit or miss Monte Carlo method we accurately estimate the tumor volume. Starting from the previous tumor volumes time series recorded during the first six months of evolution we applied both a linear, exponential and logarithmic smoothing to forecast the future size of the HCC tumor in the next six months. Our conclusion was that a dynamic forecasting model of HCC volumes could be very accurate for the assessment of tumor volume doubling time usually obtained by two discrete volume measurements of the tumor.

  6. [Growth patterns of Leymus chinensis clones under different habitat conditions in Songnen Plain of China].

    PubMed

    Yang, Yunfei; Zhang, Baotian

    2006-08-01

    A tracking investigation was conducted in the Songnen Plain of China on the experimental clones of Leymus chinensis under cultivation, and the natural clones of this grass in the succession process of vegetation restoration after meadow flooding. The results showed that on aeolian sandy soil where existed enough growth space but no interspecific competition, there was a month interval between the transplanting of two experimental clones, and the sizes of these clones had a one-fold difference by the end of next growth season. During the whole growth season, the vegetative reproduction of the two experimental clones followed the same exponential pattern. After 6 years restoration succession on flooded meadow, the vegetative reproduction of clonal populations in L. chinensis + Carex duriuscula and L. chinensis + weed communities were all accorded with power function. On flooded alkaline meadow where existed interspecific competition, the natural clones could still increase their offspring numbers exponentially, and quickly expand their niche space at the same time.

  7. Heteroepitaxial growth of a zeolite film with a patterned surface-texture.

    PubMed

    Wakihara, Toru; Yamakita, Shigehiro; Iezumi, Kumiko; Okubo, Tatsuya

    2003-10-15

    We focus on the eteroepitaxial growth of trigonal chabazite with voids of three-dimensional intersection structures. The differences in the structures originate from the stacking sequences of the six-membered rings. Sodalite along 111 is constructed by an "abcabc" stacking sequence, while chabazite along [111] is constructed by "abab". Therefore, chabazite can grow heteroepitaxially on a sodalite substrate while keeping the relation of chabazite (111)//sodalite {111}. In this Communication, we report on the first success of the heteroepitaxial growth of a continuous zeolite (chabazite) film with a unique patterned surface-texture on a millimeter-sized sodalite single crystal. We have found that the unique texture of chabazite films is rationalized by the heteroepitaxial growth of chabazite on sodalite and the subsequent twin formation of chabazite.

  8. Patterned growth of aligned ZnO nanowire arrays on sapphire and GaN layers

    NASA Astrophysics Data System (ADS)

    Fan, H. J.; Fleischer, F.; Lee, W.; Nielsch, K.; Scholz, R.; Zacharias, M.; Gösele, U.; Dadgar, A.; Krost, A.

    2004-07-01

    Patterned growth of vertically aligned ZnO nanowire arrays on the micrometer and nanometer scale on sapphire and GaN epilayers is reported. In order to control the position and distribution density of the ZnO nanowires, Au seeding nanodots are defined, as regular arrays, with the assistance of deposition shadow masks. Electron micrographs reveal that the wires are single crystals having wire axes along the hexagonal c-axes. The epitaxial growth of ZnO nanowires on sapphire and GaN films on Si substrates was further verified by cross sectional electron microscopy investigations. Compared to the sapphire case, the perfect epitaxial growth on a GaN film on a Si substrate is believed to be more suitable for potential electronic device applications of ZnO nanowire arrays.

  9. Patterned Aqueous Growth of Single Crystalline Zinc Oxide for Photonic Applications

    NASA Astrophysics Data System (ADS)

    Pooley, Kathryn Jessica

    Typically a top-down approach is used in the fabrication of functional nanodevices beginning with the bulk material and imposing a two or three-dimensional structure on the material through a combination of lithography and etching. Pre-patterning of a substrate, resulting in the selective growth of a material, has potential for forming three-dimensional device structures in ways that can be more efficient and which can avoid process complexity and process induced damage. In this thesis, the low temperature (90°C) aqueous growth of complex, single crystalline zinc oxide (ZnO) three-dimensional devices through pre-patterned micron and nanometer sized molds is presented. This work focuses on the quality of the single crystalline ZnO material, the constrained growth of ZnO through various sizes and shapes of molds, and the fabrication of several device structures including pillars, rings, and photonic crystals. Due to their single crystalline nature and crystallographically smooth sidewalls, photonic devices created using this growth method have the potential to outperform traditionally fabricated structures in a range of optoelectronic applications. In addition, metal-oxide interfaces are the critical components of many electrical and optical devices, and it is rare to find epitaxial metal-oxide structures. In this work, the first demonstration of low temperature, epitaxial growth of ZnO on single crystalline gold plates is presented. The quality and structure of the ZnO on the gold plates is investigated using scanning electron microscopy, atomic force microscopy, and photoluminescence spectroscopy. The epitaxial growth is confirmed using electron backscatter diffraction and transmission electron microscopy. The metal-oxide interfaces fabricated have the potential to be used in a number of technologically important applications. Possible examples include creating high quality electrical contacts on high bandgap materials and improving light extraction from planar

  10. Cohort study of growth patterns by gestational age in preterm infants developing morbidity

    PubMed Central

    Klevebro, S; Lundgren, P; Hammar, U; Smith, L E; Bottai, M; Domellöf, M; Löfqvist, C; Hallberg, B; Hellström, A

    2016-01-01

    Objectives To examine differences in growth patterns in preterm infants developing major morbidities including retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD), necrotising enterocolitis (NEC) and intraventricular haemorrhage (IVH). Study design Cohort study of 2521 infants born at a gestational age (GA) of 23–30 weeks from 11 level III neonatal intensive care units in USA and Canada, and 3 Swedish population-based cohorts. Outcomes Birth weight and postnatal weight gain were examined relative to birth GA and ROP, BPD, NEC and IVH development. Results Among infants with a birth GA of 25–30 weeks, birth weight SD score and postnatal weight were lower in those developing ROP and BPD. Infants developing ROP showed lower growth rates during postnatal weeks 7–9 in the 23–24 weeks GA group, during weeks 4–6 in the 25–26 weeks GA group and during weeks 1–5 in the 27–30 weeks GA group. Infants with BPD born at 27–30 weeks GA showed lower growth rates during postnatal weeks 3–5. Infants with NEC had lower growth rates after postnatal week 6 in all GA groups, with no significant differences in birth weight SD score. IVH was not associated with prenatal or postnatal growth. Conclusions In this cohort study of extremely preterm infants, we found that the postnatal growth pattern was associated with morbidities such as ROP, BPD and NEC as well as with gestational age at birth. PMID:27856479

  11. Insights into fold growth using fold-related joint patterns and mechanical stratigraphy

    NASA Astrophysics Data System (ADS)

    Savage, Heather M.; Ryan Shackleton, J.; Cooke, Michele L.; Riedel, Jeffrey J.

    2010-10-01

    Despite how common folds are as structural features, along-strike fold propagation has proven elusive to document. However, if a fold grows laterally along its axis, early-formed fold-related joints may differ significantly in orientation from joints that form later. In this paper, we integrate mechanical stratigraphy with joint pattern analysis to determine relative timing of jointing. Additionally, we demonstrate that joint patterns can be related to stresses on both the top and bottom of the bed during flexure. We present joint data from eight sedimentary beds on the fold terminus at Sheep Mountain Anticline, Wyoming, USA. The joint patterns around the terminus show two distinct patterns: joints in six of the beds show a radial pattern around the terminus whereas joint patterns in the two remaining beds differ from proximal units, despite being in the same structural position. Fracture resistance calculations confirm that the beds with mis-oriented fractures are less resistant to fracturing than other units in the study, and therefore would have fractured earlier in fold growth history. We present a plate bending model that illustrates potential joint patterns around a plunging fold nose from stresses along both the top and bottom of the bed. The joint strike predictions for the area in front of the inflection line on the fold nose match the orientations in our less resistant beds, which are now positioned behind the inflection line, suggesting that the fold grew laterally. The combined analysis of fracture pattern and mechanical stratigraphy provides a new way to investigate fold evolution.

  12. Temporal pattern of accelerated lung growth after tracheal occlusion in the fetal rabbit.

    PubMed Central

    De Paepe, M. E.; Johnson, B. D.; Papadakis, K.; Sueishi, K.; Luks, F. I.

    1998-01-01

    Tracheal occlusion in utero is a potent stimulus of fetal lung growth. We describe the early growth mechanics of fetal lungs and type II pneumocytes after tracheal ligation (TL). Fetal rabbits underwent TL at 24 days gestational age (DGA; late pseudoglandular stage; term = 31 to 33 days) and were sacrificed at time intervals ranging from 1 to 5 days after TL. Lung growth was measured by stereological volumetry and bromodeoxyuridine (BrdU) pulse labeling. Pneumocyte II population kinetics were analyzed using a combination of anti-surfactant protein A and BrdU immunohistochemistry and computer-assisted morphometry. Nonoperated littermates served as controls. TL resulted in dramatically enhanced lung growth (lung weight/body weight was 5.00 +/- 0.81% in TL versus 2.52 +/- 0.13% in controls at 29 DGA; P < 0.001, unpaired Student's t-test). Post-TL lung growth was characterized by a 3-day lag-phase typified by relative stagnation of growth, followed by distension of airspaces, increased cell proliferation, and accelerated architectural and cellular maturation by postligation days 4 and 5. During the proliferation phase, the replicative activity of type II cells was markedly increased (type II cell BrdU labeling index was 10.0 +/- 4.1% in TL versus 1.1 +/- 0.3% for controls at 29 DGA; P < 0.02), but their numerical density decreased (3.0 +/- 0.5 x 10(-3)/microm2 in TL versus 4.5 +/- 0.3 x 10(-3)/microm2 in controls at 29 DGA; P < 0.02), suggesting accelerated terminal differentiation to type I cells. In conclusion, post-TL lung development is characterized by a well defined temporal pattern of lung growth and maturation. The rabbit model lends itself well to study the regulatory mechanisms underlying accelerated fetal lung growth after TL. Images Figure 2 Figure 4 Figure 6 Figure 8 Figure 9 PMID:9422535

  13. Growth-Curve Modeling of Nevi With a Peripheral Globular Pattern

    PubMed Central

    Bajaj, Shirin; Dusza, Stephen W.; Marchetti, Michael A.; Wu, Xinyuan; Fonseca, Maira; Kose, Kivanc; Brito, Johanna; Carrera, Cristina; Martins de Silva, Vanessa P.; Malvehy, Josep; Puig, Susana; Yagerman, Sarah; Liebman, Tracey N.; Scope, Alon; Halpern, Allan C.; Marghoob, Ashfaq A.

    2017-01-01

    IMPORTANCE Although nevi with a peripheral rim of globules (peripheral globular nevi [PGN]) observed with dermoscopy are associated with enlarging melanocytic nevi, their actual growth dynamics remain unknown. Because change is a sensitive but nonspecific marker for melanoma, beginning to understand the growth patterns of nevi may improve the ability of physicians to differentiate normal from abnormal growth and reduce unnecessary biopsies. OBJECTIVE To study the growth dynamics and morphologic evolution of PGN on dermoscopy. DESIGN, SETTING, AND PARTICIPANTS A total of 84 participants with 121 PGN from September 1, 1999, through May 1, 2013, were identified retrospectively. Cohorts were recruited from the Memorial Sloan Kettering Cancer Center; Melanoma Unit of the Hospital Clinic, University of Barcelona; and Study of Nevi in Children. All 3 cohorts underwent longitudinal monitoring with serial dermoscopic imaging of their PGN. Data analysis was performed from May 1, 2014, through April 1, 2015. MAIN OUTCOMES AND MEASURES Establishment of the natural growth curve of PGN. The secondary aim was to establish the median time to growth cessation in those PGN for which the size eventually stabilized and/or had begun to decrease during the study period. RESULTS The median duration of follow-up was 25.1 (range, 2.0–114.4) months. Most of the nevi (116 [95.9%]) enlarged at some point during sequential monitoring. The rate of increase in the surface area of PGN varied among cohorts and ranged from −0.47 to 2.26mm2/mo (mean rate, 0.25 [95% CI, 0.14–0.36]mm2/mo). The median time to growth cessation in the 26 PGN that stabilized or decreased in size (21.5%) was 58.6 months. All lesions changed in a symmetric manner and 91 (75.2%) displayed a decrease in the density of peripheral globules over time. CONCLUSIONS AND RELEVANCE Nevi displaying a peripheral globular pattern enlarged symmetrically with apparent growth cessation occurring during a span of 4 to 5 years. Our

  14. Dynamic Tumor Growth Patterns in a Novel Murine Model of Colorectal Cancer

    PubMed Central

    Olson, Terrah J. Paul; Hadac, Jamie N.; Sievers, Chelsie K.; Leystra, Alyssa A.; Deming, Dustin A.; Zahm, Christopher D.; Albrecht, Dawn M.; Nomura, Alice; Nettekoven, Laura A.; Plesh, Lauren K.; Clipson, Linda; Sullivan, Ruth; Newton, Michael A.; Schelman, William R.; Halberg, Richard B.

    2014-01-01

    Colorectal cancer (CRC) often arises from adenomatous colonic polyps. Polyps can grow and progress to cancer, but may also remain static in size, regress, or resolve. Predicting which progress and which remain benign is difficult. We developed a novel long-lived murine model of CRC with tumors that can be followed by colonoscopy. Our aim was to assess whether these tumors have similar growth patterns and histologic fates to human colorectal polyps to identify features to aid in risk-stratification of colonic tumors. Long-lived ApcMin/+ mice were treated with dextran sodium sulfate to promote colonic tumorigenesis. Tumor growth patterns were characterized by serial colonoscopy with biopsies obtained for immunohistochemistry and gene expression profiling. Tumors grew, remained static, regressed, or resolved over time with different relative frequencies. Newly developed tumors demonstrated higher rates of growth and resolution than more established tumors that tended to remain static in size. Colonic tumors were hyperplastic lesions (3%), adenomas (73%), intramucosal carcinomas (20%), or adenocarcinomas (3%). Interestingly, the level of β-catenin was higher in adenomas that became intratumoral carcinomas as compared to those that failed to progress. In addition, differentially expressed genes between adenomas and intramucosal carcinomas were identified. This novel murine model of intestinal tumorigenesis develops colonic tumors that can be monitored by serial colonoscopy, mirror growth patterns seen in human colorectal polyps, and progress to CRC. Further characterization of cellular and molecular features are needed to determine which features can be used to risk-stratify polyps for progression to CRC and potentially guide prevention strategies. PMID:24196829

  15. Alveolar septal patterning during compensatory lung growth: Part II the effect of parenchymal pressure gradients.

    PubMed

    Haber, Shimon; Weisbord, Michal; Mentzer, Steven J; Tsuda, Akira

    2017-05-21

    In most mammals, compensatory lung growth occurs after the removal of one lung (pneumonectomy). Although the mechanism of alveolar growth is unknown, the patterning of complex alveolar geometry over organ-sized length scales is a central question in regenerative lung biology. Because shear forces appear capable of signaling the differentiation of important cells involved in neoalveolarization (fibroblasts and myofibroblasts), interstitial fluid mechanics provide a potential mechanism for the patterning of alveolar growth. The movement of interstitial fluid is created by two basic mechanisms: 1) the non-uniform motion of the boundary walls, and 2) parenchymal pressure gradients external to the interstitial fluid. In a previous study (Haber et al., Journal of Theoretical Biology 400: 118-128, 2016), we investigated the effects of non-uniform stretching of the primary septum (associated with its heterogeneous mechanical properties) during breathing on generating non-uniform Stokes flow in the interstitial space. In the present study, we analyzed the effect of parenchymal pressure gradients on interstitial flow. Dependent upon lung microarchitecture and physiologic conditions, parenchymal pressure gradients had a significant effect on the shear stress distribution in the interstitial space of primary septa. A dimensionless parameter δ described the ratio between the effects of a pressure gradient and the influence of non-uniform primary septal wall motion. Assuming that secondary septa are formed where shear stresses were the largest, it is shown that the geometry of the newly generated secondary septa was governed by the value of δ. For δ smaller than 0.26, the alveolus size was halved while for higher values its original size was unaltered. We conclude that the movement of interstitial fluid, governed by parenchymal pressure gradients and non-uniform primary septa wall motion, provides a plausible mechanism for the patterning of alveolar growth. Copyright © 2017

  16. Using a multiscale image processing method to characterize the periodic growth patterns on scallop shells.

    PubMed

    Xing, Qiang; Wei, Tengda; Chen, Zhihui; Wang, Yangfan; Lu, Yuan; Wang, Shi; Zhang, Lingling; Bao, Zhenmin

    2017-03-01

    The fine periodic growth patterns on shell surfaces have been widely used for studies in the ecology and evolution of scallops. Modern X-ray CT scanners and digital cameras can provide high-resolution image data that contain abundant information such as the shell formation rate, ontogenetic age, and life span of shellfish organisms. We introduced a novel multiscale image processing method based on matched filters with Gaussian kernels and partial differential equation (PDE) multiscale hierarchical decomposition to segment the small tubular and periodic structures in scallop shell images. The periodic patterns of structures (consisting of bifurcation points, crossover points of the rings and ribs, and the connected lines) could be found by our Space-based Depth-First Search (SDFS) algorithm. We created a MATLAB package to implement our method of periodic pattern extraction and pattern matching on the CT and digital scallop images available in this study. The results confirmed the hypothesis that the shell cyclic structure patterns encompass genetically specific information that can be used as an effective invariable biomarker for biological individual recognition. The package is available with a quick-start guide and includes three examples: http://mgb.ouc.edu.cn/novegene/html/code.php.

  17. Identification of risk conditions for the development of adrenal disorders: how optimized PubMed search strategies makes the difference.

    PubMed

    Guaraldi, Federica; Parasiliti-Caprino, Mirko; Goggi, Riccardo; Beccuti, Guglielmo; Grottoli, Silvia; Arvat, Emanuela; Ghizzoni, Lucia; Ghigo, Ezio; Giordano, Roberta; Gori, Davide

    2014-12-01

    The exponential growth of scientific literature available through electronic databases (namely PubMed) has increased the chance of finding interesting articles. At the same time, search has become more complicated, time consuming, and at risk of missing important information. Therefore, optimized strategies have to be adopted to maximize searching impact. The aim of this study was to formulate efficient strings to search PubMed for etiologic associations between adrenal disorders (ADs) and other conditions. A comprehensive list of terms identifying endogenous conditions primarily affecting adrenals was compiled. An ad hoc analysis was performed to find the best way to express each term in order to find the highest number of potentially pertinent articles in PubMed. A predefined number of retrieved abstracts were read to assess their association with ADs' etiology. A more sensitive (providing the largest literature coverage) and a more specific (including only those terms retrieving >40 % of potentially pertinent articles) string were formulated. Various researches were performed to assess strings' ability to identify articles of interest in comparison with non-optimized literature searches. We formulated optimized, ready applicable tools for the identification of the literature assessing etiologic associations in the field of ADs using PubMed, and demonstrated the advantages deriving from their application. Detailed description of the methodological process is also provided, so that this work can easily be translated to other fields of practice.

  18. The study of craniofacial growth patterns using 3D laser scanning and geometric morphometrics

    NASA Astrophysics Data System (ADS)

    Friess, Martin

    2006-02-01

    Throughout childhood, braincase and face grow at different rates and therefore exhibit variable proportions and positions relative to each other. Our understanding of the direction and magnitude of these growth patterns is crucial for many ergonomic applications and can be improved by advanced 3D morphometrics. The purpose of this study is to investigate this known growth allometry using 3D imaging techniques. The geometry of the head and face of 840 children, aged 2 to 19, was captured with a laser surface scanner and analyzed statistically. From each scan, 18 landmarks were extracted and registered using General Procrustes Analysis (GPA). GPA eliminates unwanted variation due to position, orientation and scale by applying a least-squares superimposition algorithm to individual landmark configurations. This approach provides the necessary normalization for the study of differences in size, shape, and their interaction (allometry). The results show that throughout adolescence, boys and girls follow a different growth trajectory, leading to marked differences not only in size but also in shape, most notably in relative proportions of the braincase. These differences can be observed during early childhood, but become most noticeable after the age of 13 years, when craniofacial growth in girls slows down significantly, whereas growth in boys continues for at least 3 more years.

  19. Neighbor Detection Induces Organ-Specific Transcriptomes, Revealing Patterns Underlying Hypocotyl-Specific Growth.

    PubMed

    Kohnen, Markus V; Schmid-Siegert, Emanuel; Trevisan, Martine; Petrolati, Laure Allenbach; Sénéchal, Fabien; Müller-Moulé, Patricia; Maloof, Julin; Xenarios, Ioannis; Fankhauser, Christian

    2016-12-01

    In response to neighbor proximity, plants increase the growth of specific organs (e.g., hypocotyls) to enhance access to sunlight. Shade enhances the activity of Phytochrome Interacting Factors (PIFs) by releasing these bHLH transcription factors from phytochrome B-mediated inhibition. PIFs promote elongation by inducing auxin production in cotyledons. In order to elucidate spatiotemporal aspects of the neighbor proximity response, we separately analyzed gene expression patterns in the major light-sensing organ (cotyledons) and in rapidly elongating hypocotyls of Arabidopsis thaliana PIFs initiate transcriptional reprogramming in both organs within 15 min, comprising regulated expression of several early auxin response genes. This suggests that hypocotyl growth is elicited by both local and distal auxin signals. We show that cotyledon-derived auxin is both necessary and sufficient to initiate hypocotyl growth, but we also provide evidence for the functional importance of the local PIF-induced response. With time, the transcriptional response diverges increasingly between organs. We identify genes whose differential expression may underlie organ-specific elongation. Finally, we uncover a growth promotion gene expression signature shared between different developmentally regulated growth processes and responses to the environment in different organs. © 2016 American Society of Plant Biologists. All rights reserved.

  20. Changes in growth patterns in mouse condylar cartilage associated with skeletal maturation and senescence.

    PubMed

    Livne, E; Weiss, A; Silbermann, M

    1990-01-01

    The squamoso-mandibular joint (SMJ) represents one of the most active joints in the mouse. In the young animal the main function of condylar cartilage in the SMJ is to serve as a growth center for the developing mandible. This first phase of skeletal growth lasts up to the age of 6-8 weeks, and is manifested by appositional growth of cartilage followed by endochondral ossification. Thereafter, the condylar cartilage gradually changes its function and serves mainly as an articulating surface for the joint. Consequently, the cartilage changes from a calcifying hyaline cartilage to a fibrous non-calcifying cartilage. The latter phase lasts through the stage of maturation (6 months of age) and it is manifested by a combination of appositional and interstitial patterns of cellular growth. Thereafter, the third phase develops which is characterized by degenerative changes that typify the aging process. In vivo autoradiography with [3H]-thymidine indicated that in the very young animal labeled cells are confined to the chondroprogenitor (proliferative) zone of the condylar cartilage. With maturation, the dimension of this zone as well as the number of labeled cells decrease, so that by 3 months of age the labeling index decreases by 30%. By the age of 6, 12 and 18 months, almost no cells take up the radioisotope while the total number of cells declines. During senescence only a very limited interstitial growth is taking place, a feature that might be associated with the repair processes that accompany the onset of osteoarthritic lesions.

  1. Neighbor Detection Induces Organ-Specific Transcriptomes, Revealing Patterns Underlying Hypocotyl-Specific Growth[OPEN

    PubMed Central

    Trevisan, Martine; Petrolati, Laure Allenbach

    2016-01-01

    In response to neighbor proximity, plants increase the growth of specific organs (e.g., hypocotyls) to enhance access to sunlight. Shade enhances the activity of Phytochrome Interacting Factors (PIFs) by releasing these bHLH transcription factors from phytochrome B-mediated inhibition. PIFs promote elongation by inducing auxin production in cotyledons. In order to elucidate spatiotemporal aspects of the neighbor proximity response, we separately analyzed gene expression patterns in the major light-sensing organ (cotyledons) and in rapidly elongating hypocotyls of Arabidopsis thaliana. PIFs initiate transcriptional reprogramming in both organs within 15 min, comprising regulated expression of several early auxin response genes. This suggests that hypocotyl growth is elicited by both local and distal auxin signals. We show that cotyledon-derived auxin is both necessary and sufficient to initiate hypocotyl growth, but we also provide evidence for the functional importance of the local PIF-induced response. With time, the transcriptional response diverges increasingly between organs. We identify genes whose differential expression may underlie organ-specific elongation. Finally, we uncover a growth promotion gene expression signature shared between different developmentally regulated growth processes and responses to the environment in different organs. PMID:27923878

  2. Dynamics of growth zone patterning in the milkweed bug Oncopeltus fasciatus.

    PubMed

    Auman, Tzach; Vreede, Barbara M I; Weiss, Aryeh; Hester, Susan D; Williams, Terri A; Nagy, Lisa M; Chipman, Ariel D

    2017-05-15

    We describe the dynamic process of abdominal segment generation in the milkweed bug Oncopeltus fasciatus We present detailed morphological measurements of the growing germband throughout segmentation. Our data are complemented by cell division profiles and expression patterns of key genes, including invected and even-skipped as markers for different stages of segment formation. We describe morphological and mechanistic changes in the growth zone and in nascent segments during the generation of individual segments and throughout segmentation, and examine the relative contribution of newly formed versus existing tissue to segment formation. Although abdominal segment addition is primarily generated through the rearrangement of a pool of undifferentiated cells, there is nonetheless proliferation in the posterior. By correlating proliferation with gene expression in the growth zone, we propose a model for growth zone dynamics during segmentation in which the growth zone is functionally subdivided into two distinct regions: a posterior region devoted to a slow rate of growth among undifferentiated cells, and an anterior region in which segmental differentiation is initiated and proliferation inhibited. © 2017. Published by The Company of Biologists Ltd.

  3. Dynamics of growth zone patterning in the milkweed bug Oncopeltus fasciatus

    PubMed Central

    Weiss, Aryeh; Williams, Terri A.; Nagy, Lisa M.

    2017-01-01

    We describe the dynamic process of abdominal segment generation in the milkweed bug Oncopeltus fasciatus. We present detailed morphological measurements of the growing germband throughout segmentation. Our data are complemented by cell division profiles and expression patterns of key genes, including invected and even-skipped as markers for different stages of segment formation. We describe morphological and mechanistic changes in the growth zone and in nascent segments during the generation of individual segments and throughout segmentation, and examine the relative contribution of newly formed versus existing tissue to segment formation. Although abdominal segment addition is primarily generated through the rearrangement of a pool of undifferentiated cells, there is nonetheless proliferation in the posterior. By correlating proliferation with gene expression in the growth zone, we propose a model for growth zone dynamics during segmentation in which the growth zone is functionally subdivided into two distinct regions: a posterior region devoted to a slow rate of growth among undifferentiated cells, and an anterior region in which segmental differentiation is initiated and proliferation inhibited. PMID:28432218

  4. Distinct patterns of kidney and liver cyst growth in pkd2(WS25/−) mice

    PubMed Central

    Doctor, R. Brian; Serkova, Natalie J.; Hasebroock, Kendra M.; Zafar, Iram; Edelstein, Charles L.

    2010-01-01

    Background. Autosomal dominant polycystic kidney disease (ADPKD) is a common genetic disease that results in the development of cystic kidneys and liver. Pkd2(WS25/−) mice are a key genetic mouse model of human ADPKD that recapitulate the ‘molecular recessive’ nature of human ADPKD. Providing the foundation for future long-term studies, the present work documents distinct patterns of long-term cyst growth in the kidneys and liver of male and female pkd2(WS25/−) mice. Methods. Gravimetric measurements documented the progression of kidney and liver growth in male and female pkd2(WS25/−) mice over 12 months. A fast imaging with steady-state precision–magnetic resonance imaging (FISP-MRI) technique to measure kidney and liver organ and cyst volumes was optimized and validated. Longitudinal FISP-MRI analyses of changes in cyst volumes were performed in pkd2(WS25/−) mice over 15 months. Results. Male and female pkd2(WS25/−) mice had significant increases in kidney weights after 4 months of age. The progression of kidney growth was minimal after 4 months of age. Liver cyst growth in male pkd2(WS25/−) mice was minimal after 4 months of age but showed an accelerated rate of growth after 8 months of age. Female pkd2(WS25/−) mice also showed accelerated growth but this was delayed in time when compared with male pkd2(WS25/−) mice. Conclusions. Pkd2(WS25/−) mice are a genetic mouse model that recapitulates the early phenotypic characteristics of human ADPKD kidney cystogenesis. Male pkd2(WS25/−) mice consistently display a late progression in liver growth that is seen in clinically impacted livers of human ADPKD patients. PMID:20388629

  5. Parasite-mediated growth patterns and nutritional constraints in a cavity-nesting bird.

    PubMed

    O'Brien, Erin L; Dawson, Russell D

    2008-01-01

    1. Trade-offs between growth and immunity of nestling birds can be influenced by parasites, but the magnitude of these effects may depend on availability of critical dietary nutrients. Owing to their importance for both immune system function and growth, dietary carotenoids have the potential to mediate parasite-induced developmental strategies of avian hosts. 2. The effects of ectoparasitic blow flies Protocalliphora spp. and dietary carotenoids (lutein and zeaxanthin) on immune function and patterns of growth in nestling mountain bluebirds Sialia currucoides were investigated by combining parasite removal and carotenoid supplementation treatments in a 2 x 2 design. 3. Supplemental carotenoids enhanced nestlings' T-cell-mediated immune response following intradermal injection of phytohaemagglutinin. 4. The effect of carotenoid supplementation on rate of mass gain depended on whether broods were exposed to parasites: among parasitized broods, those receiving supplemental carotenoids gained mass more rapidly than nonsupplemented broods, whereas there was no effect of supplemental carotenoids on growth of mass in broods that had parasites removed. This suggests that additional dietary carotenoids allowed nestlings to compensate for the otherwise detrimental effects of parasites on mass gain. For length of the eighth primary feather at fledging, early and late broods differed in their response to parasitism: early broods showed an increase in feather length when parasites were removed, while nestlings in late broods had shorter feathers in the absence of parasites. We suggest that this may reflect within-season variation in parasite-mediated growth strategies of nestlings. 5. Maternal condition was positively associated with mass, condition and rate of feather growth of offspring under all conditions, and also influenced nestling immunocompetence, but only in the absence of parasites. 6. We conclude that dietary carotenoids alleviate some of the detrimental effects of

  6. The impact of arbuscular mycorrhizal fungi on plant growth following herbivory: A search for pattern

    NASA Astrophysics Data System (ADS)

    Borowicz, Victoria A.

    2013-10-01

    Arbuscular mycorrhizal (AM) fungi can facilitate nutrient uptake and increase host plant growth but also place constraints on the host's carbon budget. When plants are stressed by herbivory the net effect of the symbiosis may be altered tolerance. Individual experiments manipulating AM fungi and herbivory have demonstrated increased, decreased, and no effect on tolerance but patterns with respect to plant, herbivore, or fungus characteristics have not emerged. Meta-analysis of published results from factorial experiments was used to describe the size of the effects of herbivory and of AM fungi on host growth when factors such as cause of damage, inoculum, and host characteristics are considered, and to determine whether AM fungi alter the effects of herbivory. Also, the correlation between the effect of AM fungi on tolerance and resistance was tested with data from studies that examined insect performance. Herbivory strongly and consistently reduced shoot and root growth, especially in perennial plants and crops. AM fungi increased shoot growth of perennials but not annuals, and when insects caused damage but not when artificial defoliation was applied. Root growth was consistently greater with AM fungi. The interaction of AM fungi and herbivory, which indicates whether AM fungi alter the effects of herbivory, was variable and never significant overall but homogeneity tests indicated underlying structure. In experiments that used single species inoculum, Glomus intraradices increased, whereas Glomus mosseae reduced, effects of herbivory on shoot growth. Multispecies inocula magnified effects of herbivory on root growth whereas single species inocula ameliorated effects. The impact of AM fungi on resistance to herbivory was positively correlated with the impact on tolerance; however AM fungi reduced both tolerance and resistance in many cases. Review of these results with respect to the types of systems studied suggests directions for future investigation.

  7. Chemically Engineered Substrates for Patternable Growth of Two-Dimensional Chalcogenide Crystals.

    PubMed

    Wang, Mingzhan; Wu, Jinxiong; Lin, Li; Liu, Yujing; Deng, Bing; Guo, Yunfan; Lin, Yuanwei; Xie, Tian; Dang, Wenhui; Zhou, Yubing; Peng, Hailin

    2016-11-22

    The key challenge of direct integration of two-dimensional (2D) chalcogenide crystals into functional modules is precise control of the nucleation sites of the building blocks. Herein, we exploit the chemical activities and surface engineering of the substrates to manipulate the nucleation energy barrier of 2D crystals and thereby realize the patternable growth of 2D crystals. The selective-region chemical modifications of the substrates are achieved via microcontact printing combined with the elegant self-assembly of octadecyltrichlorosilane molecules on the substrates. The patternable growth method is versatile and can be used as a general strategy for growing a broad class of high-quality 2D chalcogenide crystals with tailorable configurations on a variety of chemically engineered substrates. Moreover, we demonstrate flexible transparent electrodes based on large-scale patterned nanogrids of topological insulator Bi2Se3, which possess tailored trade-off between electric conductivity and optical transmittance across the visible to near-infrared regime. We hope this method may open an avenue to the efficient integration and batch production of 2D chalcogenide crystals and could inspire ongoing efforts of the fabrication of van der Waals heterostructures.

  8. Food consumption patterns and economic growth. Increasing affluence and the use of natural resources.

    PubMed

    Gerbens-Leenes, P W; Nonhebel, S; Krol, M S

    2010-12-01

    This study analyzes relationships between food supply, consumption and income, taking supply, meat and dairy, and consumption composition (in macronutrients) as indicators, with annual per capita GDP as indicator for income. It compares food consumption patterns for 57 countries (2001) and gives time trends for western and southern Europe. Cross-sectional and time series relationships show similar patterns of change. For low income countries, GDP increase is accompanied by changes towards food consumption patterns with large gaps between supply and actual consumption. Total supply differs by a factor of two between low and high income countries. People in low income countries derive nutritional energy mainly from carbohydrates; the contribution of fats is small, that of protein the same as for high income countries and that of meat and dairy negligible. People in high income countries derive nutritional energy mainly from carbohydrates and fat, with substantial contribution of meat and dairy. Whenever and wherever economic growth occurs, food consumption shows similar change in direction. The European nutrition transition happened gradually, enabling agriculture and trade to keep pace with demand growth. Continuation of present economic trends might cause significant pressure on natural resources, because changes in food demand occur much faster than in the past, especially in Asia.

  9. A preliminary investigation of cell growth after irradiation using a modulated x-ray intensity pattern

    NASA Astrophysics Data System (ADS)

    Bromley, Regina; Davey, Ross; Oliver, Lyn; Harvie, Rozelle; Baldock, Clive

    2006-08-01

    In this study we have investigated a spatial distribution of cell growth after their irradiation using a modulated x-ray intensity pattern. An A549 human non-small cell lung cancer cell line was grown in a 6-well culture. Two of the wells were the unirradiated control wells, whilst another two wells were irradiated with a modulated x-ray intensity pattern and the third two wells were uniformly irradiated. A number of plates were incubated for various times after irradiation and stained with crystal violet. The spatial distribution of the stained cells within each well was determined by measurement of the crystal violet optical density at multiple positions in the plate using a microplate photospectrometer. The crystal violet optical density for a range of cell densities was measured for the unirradiated well and this correlated with cell viability as determined by the MTT cell viability assay. An exponential dose response curve was measured for A549 cells from the average crystal violet optical density in the uniformly irradiated well up to a dose of 30 Gy. By measuring the crystal violet optical density distribution within a well the spatial distribution of cell growth after irradiation with a modulated x-ray intensity pattern can be plotted. This method can be used for in vitro investigation into the changes in radiation response associated with treatment using intensity modulated radiation therapy (IMRT).

  10. Controlled Patterning and Growth of Single Wall and Multi-wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Delzeit, Lance D. (Inventor)

    2005-01-01

    Method and system for producing a selected pattern or array of at least one of a single wall nanotube and/or a multi-wall nanotube containing primarily carbon. A substrate is coated with a first layer (optional) of a first selected metal (e.g., Al and/or Ir) and with a second layer of a catalyst (e.g., Fe, Co, Ni and/or Mo), having selected first and second layer thicknesses provided by ion sputtering, arc discharge, laser ablation, evaporation or CVD. The first layer and/or the second layer may be formed in a desired non-uniform pattern, using a mask with suitable aperture(s), to promote growth of carbon nanotubes in a corresponding pattern. A selected heated feed gas (primarily CH4 or C2Hn with n=2 and/or 4) is passed over the coated substrate and forms primarily single wall nanotubes or multiple wall nanotubes, depending upon the selected feed gas and its temperature. Nanofibers, as well as single wall and multi-wall nanotubes, are produced using plasma-aided growth from the second (catalyst) layer. An overcoating of a selected metal or alloy can be deposited, over the second layer, to provide a coating for the carbon nanotubes grown in this manner.

  11. A preliminary investigation of cell growth after irradiation using a modulated x-ray intensity pattern.

    PubMed

    Bromley, Regina; Davey, Ross; Oliver, Lyn; Harvie, Rozelle; Baldock, Clive

    2006-08-07

    In this study we have investigated a spatial distribution of cell growth after their irradiation using a modulated x-ray intensity pattern. An A549 human non-small cell lung cancer cell line was grown in a 6-well culture. Two of the wells were the unirradiated control wells, whilst another two wells were irradiated with a modulated x-ray intensity pattern and the third two wells were uniformly irradiated. A number of plates were incubated for various times after irradiation and stained with crystal violet. The spatial distribution of the stained cells within each well was determined by measurement of the crystal violet optical density at multiple positions in the plate using a microplate photospectrometer. The crystal violet optical density for a range of cell densities was measured for the unirradiated well and this correlated with cell viability as determined by the MTT cell viability assay. An exponential dose response curve was measured for A549 cells from the average crystal violet optical density in the uniformly irradiated well up to a dose of 30 Gy. By measuring the crystal violet optical density distribution within a well the spatial distribution of cell growth after irradiation with a modulated x-ray intensity pattern can be plotted. This method can be used for in vitro investigation into the changes in radiation response associated with treatment using intensity modulated radiation therapy (IMRT).

  12. Implementing smart growth strategies in rural America: development patterns that support public health goals.

    PubMed

    Dalbey, Matthew

    2008-01-01

    Recent studies on obesity rates show alarming increases across the entire population. Some of these studies indicate higher rates of obesity in rural populations than urban and suburban populations. Obesity in children in rural places also outpaces their suburban and urban counterparts. Although a number of factors account for these differences, public health professionals and researchers have begun to recognize that conventional development patterns and land use policies in rural areas are playing an important role in the trend. Smart growth alternatives to current rural development patterns also support broad public health goals. Rural communities across America face a number of challenges, yet many are using smart growth development strategies to turn the challenges into opportunities. These strategies are structured in a way that builds on broadly held values in rural communities, ones that build upon the traditional development pattern and support multiple community goals. Public health professionals, managers, and academics will benefit from this discussion because it will explain the strategies that rural decision makers, planners, and citizens are adopting to create places that support multiple community goals including a built environment that sustains and promotes active living.

  13. Ink-jetable patterning of metal-catalysts for regioselective growth of nanowires

    NASA Astrophysics Data System (ADS)

    Zopes, David; von Hagen, Robin; Müller, Ralf; Fiz, Raquel; Mathur, Sanjay

    2010-10-01

    Nanosized (20-30 nm) colloidal gold, silver and their alloys were obtained by reductive transformation of corresponding metal salts. Dispersions of metal nanoparticles (σ < 4%) in aqueous solutions were obtained by appropriate surface functionalization which led to inorganic inks with solid fraction ranging from 0.01-4%. Judicious choice of a polymer additive (polyethylene glycol or carboxymethyl cellulose) was found to be crucial to avoid the agglomeration of nanocrystals in the ink-jetted structures upon solvent evaporation. The versatility of the nanoparticle-based printing technology was demonstrated by fabrication of dot-matrices and circuitry patterns on different substrates. Characterization of printed structures showed a homogeneous topography (AFM) and uniform distribution of metallic nanoparticles (SEM/TEM) within the ink-jetted microdrops. The site-specific patterning on silicon (001) substrates with nanoparticle (mono)layers could also be achieved by printing the linker molecule, aminopropyltriethoxysilane, followed by selective attachment of gold nanoparticles. Positionally ordered and chemically bonded gold catalyst patterns were used for the chemical vapour deposition (CVD) of nanowires, which led to site-specific growth of nanowires via the vapour-liquid-solid (VLS) mechanism and unlike in the case of spin-coated metal colloids no significant lateral diffusion of metal nanoparticles was observed, in chemically anchored Au nanoparticles. Nanoparticle containing inks allow a user-defined dilution to vary the density of CVD grown nanowires, which was utilized to show the differences in catalytic activities of silver and gold catalysts in the VLS growth.

  14. Field Heterogeneity Patterns as a Crucial Factor for Improving Crop Growth Simulations

    NASA Astrophysics Data System (ADS)

    Stadler, A.; Kupisch, M.; Langensiepen, M.; Ewert, F.

    2012-12-01

    Agricultural ecosystems depend on environmental factors, especially the weather and the soil characteristics. Heterogeneous conditions within a field cause spatial variations of biomass, leaf area index and yield. The effects of varying spatial conditions on crop growth are generally examined on different spatial scales, but just few studies address spatial heterogeneity at the field level. Since crop growth models try to represent an image of reality, they should consider variations in field conditions, especially regarding small-scale simulations and precision agriculture. Some studies already described that the tested models are able to represent spatial heterogeneity at regional scale, if parameters of environmental conditions are adapted. Therefore, we hypothesize that taking into account the effects of soil heterogeneity on plant water and nutrient uptake also improves the accuracy of crop growth models at field scale. A crop growth model was applied using information from winter wheat and sugar beet field trials carried out near Jülich, located in the central western part of Germany. These fields are all characterized by strong spatial variability in soil conditions and managed according to standard agronomic practice. The crop growth model was calibrated separately for each winter wheat and sugar beet cultivar grown on these fields by adjusting the respective parameters with the help of crop physiological measurements at point level. The soil model was parameterized for different field sample points with electromagnetic induction measurements to account for the spatial heterogeneity in soil conditions within each field. After that, the crop growth model was tested whether it could reproduce the observed spatial patterns of crop growth in the selected fields (2010 - 2012) by considering the spatial variability in soil properties. The analysis of our measurements on heterogeneous winter wheat fields showed a distribution of soil properties whose patterns are

  15. Development of the maxillary sinus from birth to age 18. Postnatal growth pattern.

    PubMed

    Lorkiewicz-Muszyńska, Dorota; Kociemba, Wojciech; Rewekant, Artur; Sroka, Alicja; Jończyk-Potoczna, Katarzyna; Patelska-Banaszewska, Magdalena; Przystańska, Agnieszka

    2015-09-01

    Anatomical and developmental descriptions of the maxillary sinus may be of great clinical importance. An understanding of age-related changes in the dimensions and volume of the normal maxillary sinus may help in the evaluation of radiographs and identification of sinus abnormalities. The aim of the present study was to define growth patterns of maxillary sinuses in children up to the age of 18 years and evaluate the correlation between normal age-related changes in dimensions and volume. The research sample consisted of CT scans of 170 patients subdivided into 17 groups based on age. Normal developmental changes were investigated and linear dimensions measured. The maxillary sinus, present at birth, increases in size until the end of the 18th year. The growth pattern includes changes in vertical, horizontal and antero-posterior directions. No bilateral dimorphism was observed, but gender-related differences were found in children over the age of 8 years. The most extensive period of growth occurs during the first 8 years and by the end of the 16th year the maximal values of all diameters and volume are reached. A CT study of developing maxillary sinuses allowed a precise evaluation of age-related changes in all diameters and volume to be made. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  16. Interpulse interval in circulating growth hormone patterns regulates sexually dimorphic expression of hepatic cytochrome P450.

    PubMed Central

    Waxman, D J; Pampori, N A; Ram, P A; Agrawal, A K; Shapiro, B H

    1991-01-01

    Plasma growth hormone (GH) profiles are sexually differentiated in many species and regulate the sex-dependence of peripubescent growth rates and liver function, including steroid hydroxylase cytochrome P450 expression, by mechanisms that are poorly understood. By use of an external pump to deliver to hypophysectomized rats pulses of rat GH of varying frequency and amplitude, a critical element for liver discrimination between male and female GH patterns was identified. Liver expression of the male-specific steroid 2 alpha (or 16 alpha)-hydroxylase P450, designated CYP2C11, was stimulated by GH at both physiological and nonphysiological pulse amplitudes, durations, and frequencies, provided that an interpulse interval of no detectable GH was maintained for at least 2.5 hr. This finding suggests that hepatocytes undergo an obligatory recovery period after stimulation by a GH pulse. This period may be required to reset a GH-activated intracellular signaling pathway or may relate to the short-term absence of GH receptors at the hepatocyte surface after a cycle of GH binding and receptor internalization. These requirements were distinguished from those necessary for the stimulation by GH of normal male growth rates in hypophysectomized rats, indicating that different GH responses and, perhaps, different GH-responsive tissues recognize distinct signaling elements in the sexually dimorphic patterns of circulating GH. Images PMID:1862110

  17. Interpulse interval in circulating growth hormone patterns regulates sexually dimorphic expression of hepatic cytochrome P450.

    PubMed

    Waxman, D J; Pampori, N A; Ram, P A; Agrawal, A K; Shapiro, B H

    1991-08-01

    Plasma growth hormone (GH) profiles are sexually differentiated in many species and regulate the sex-dependence of peripubescent growth rates and liver function, including steroid hydroxylase cytochrome P450 expression, by mechanisms that are poorly understood. By use of an external pump to deliver to hypophysectomized rats pulses of rat GH of varying frequency and amplitude, a critical element for liver discrimination between male and female GH patterns was identified. Liver expression of the male-specific steroid 2 alpha (or 16 alpha)-hydroxylase P450, designated CYP2C11, was stimulated by GH at both physiological and nonphysiological pulse amplitudes, durations, and frequencies, provided that an interpulse interval of no detectable GH was maintained for at least 2.5 hr. This finding suggests that hepatocytes undergo an obligatory recovery period after stimulation by a GH pulse. This period may be required to reset a GH-activated intracellular signaling pathway or may relate to the short-term absence of GH receptors at the hepatocyte surface after a cycle of GH binding and receptor internalization. These requirements were distinguished from those necessary for the stimulation by GH of normal male growth rates in hypophysectomized rats, indicating that different GH responses and, perhaps, different GH-responsive tissues recognize distinct signaling elements in the sexually dimorphic patterns of circulating GH.

  18. The Growth Pattern of Tibetan Infants at High Altitudes: a Cohort Study in Rural Tibet region

    PubMed Central

    Wang, Weihua; Liu, Feng; Zhang, Zhicheng; Zhang, Yi; Fan, Xiaojing; Liu, Ruru; Dang, Shaonong

    2016-01-01

    Studies on growth pattern of Tibetan infants and the difference from other child groups were limited due to its special living environment and unique customs. In this study, 253 Tibetan infants were followed-up from their birth to 12th month in rural Tibet. Five visits were conducted and weight and length were measured at each visit. Mixed model was employed to analyze the growth pattern of Tibetan infants and its comparison to the Han infants. Propensity Scores (PS) technique was adopted to control for the potential confounding factors. The mixed model found that the birth weight/length had a negative impact on the increment of Tibetan infants after birth (weight: β = −0.6819, P < 0.0001, length: β = −0.9571, P < 0.0001). The weight increment of Tibetan infants was greater than Han infant with age (βage*ethnic = 0.0345, P < 0.001), after using PS as a covariant. And another mixed model in which PS was used as a matching factor found similar trend. Compared with Chinese Han infants, Tibetan infants were lower weight and shorter length within one year after birth but they had greater increment of weight, suggesting that Tibetan infants might have a significant catch-up growth within the first year of life. PMID:27694843

  19. Pattern, growth, and aging in aggregation kinetics of a Vicsek-like active matter model

    NASA Astrophysics Data System (ADS)

    Das, Subir K.

    2017-01-01

    Via molecular dynamics simulations, we study kinetics in a Vicsek-like phase-separating active matter model. Quantitative results, for isotropic bicontinuous pattern, are presented on the structure, growth, and aging. These are obtained via the two-point equal-time density-density correlation function, the average domain length, and the two-time density autocorrelation function. Both the correlation functions exhibit basic scaling properties, implying self-similarity in the pattern dynamics, for which the average domain size exhibits a power-law growth in time. The equal-time correlation has a short distance behavior that provides reasonable agreement between the corresponding structure factor tail and the Porod law. The autocorrelation decay is a power-law in the average domain size. Apart from these basic similarities, the overall quantitative behavior of the above-mentioned observables is found to be vastly different from those of the corresponding passive limit of the model which also undergoes phase separation. The functional forms of these have been quantified. An exceptionally rapid growth in the active system occurs due to fast coherent motion of the particles, mean-squared-displacements of which exhibit multiple scaling regimes, including a long time ballistic one.

  20. Quantitative spectral light scattering polarimetry for monitoring fractal growth pattern of Bacillus thuringiensis bacterial colonies

    NASA Astrophysics Data System (ADS)

    Banerjee, Paromita; Soni, Jalpa; Ghosh, Nirmalya; Sengupta, Tapas K.

    2013-02-01

    It is of considerable current interest to develop various methods which help to understand and quantify the cellular association in growing bacterial colonies and is also important in terms of detection and identification of a bacterial species. A novel approach is used here to probe the morphological structural changes occurring during the growth of the bacterial colony of Bacillus thuringiensis under different environmental conditions (in normal nutrient agar, in presence of glucose - acting as additional nutrient and additional 3mM arsenate as additional toxic material). This approach combines the quantitative Mueller matrix polarimetry to extract intrinsic polarization properties and inverse analysis of the polarization preserving part of the light scattering spectra to determine the fractal parameter H (Hurst exponent) using Born approximation. Interesting differences are observed in the intrinsic polarization parameters and also in the Hurst exponent, which is a measurement of the fractality of a pattern formed by bacteria while growing as a colony. These findings are further confirmed with optical microscopic studies of the same sample and the results indicate a very strong and distinct dependence on the environmental conditions during growth, which can be exploited to quantify different bacterial species and their growth patterns.

  1. Pattern formation in fiber-reinforced tubular tissues: Folding and segmentation during epithelial growth

    NASA Astrophysics Data System (ADS)

    Ciarletta, P.; Ben Amar, M.

    2012-03-01

    Constrained growth processes in living materials result in a complex distribution of residual strains, which in certain geometries may induce a bifurcation in the elastic stability. In this work, we investigate the combined effects of growth and material anisotropy in the epithelial pattern formation of tubular tissues. In order to represent the structural organization of most organs, we adopt a strain energy density which accounts for the presence of a nonlinear reinforcement made of cross-ply fibers distributed inside a ground matrix. Using a canonical transformation in mixed polar coordinates, we transform the nonlinear elastic boundary value problem into a variational formulation, performing a straightforward derivation of the Euler-Lagrange equations for perturbations in circumferential and longitudinal directions. The corresponding curves of marginal stability are obtained numerically: the results demonstrate that both the three-dimensional distribution of residual strains and the mechanical properties of fiber reinforcements within the tissue are fundamental to determine the emergence of a specific instability pattern. In particular, different proportions of axial and circumferential residual strains can model the epithelial formation of mucosal folds in the esophagus and of plicae circulares in the small intestine. The theoretical predictions are compared with morphological data for embryonic intestinal tissues, suggesting that the volumetric growth of the epithelium can also drive the early stages of villi morphogenesis.

  2. Physiological correlates of seasonal growth patterns in lake trout Salvelinus namaycush.

    PubMed

    Morbey, Y E; Couture, P; Busby, P; Shuter, B J

    2010-12-01

    Physiological correlates of seasonal growth patterns were measured in lake trout Salvelinus namaycush from two populations with contrasting diets (zooplankton-dominated diet in Louisa Lake; fish-dominated diet in Opeongo Lake). Fish in Opeongo Lake grew faster and were in better condition than fish in Louisa Lake. The most prominent biochemical difference between populations was higher citrate synthase (CS) and cytochrome c oxidase activity in the white muscle of fish from Opeongo Lake, indicating greater sustained swimming activity in this lake. In contrast, lactate dehydrogenase (LDH) activity in white muscle, an indicator of capacity for burst swimming, was similar between lakes. Nucleoside diphosphate kinase (NDPK) activity in white muscle, an indicator of protein synthesis, was higher in Opeongo Lake than in Louisa Lake but only in the autumn. In both lakes, protein concentration and therefore nutritional status increased as the growing season progressed from spring to summer to autumn. Biochemical indicators of growth and activity showed similar seasonal patterns in the two lakes with the spring characterized by high NDPK, high CS and high LDH activities (i.e. high levels of protein synthesis in association with high aerobic and anaerobic activities). These results suggest high foraging effort and allocation to growth early in the growing season in both lakes. © 2010 The Authors. Journal of Fish Biology © 2010 The Fisheries Society of the British Isles.

  3. Semaphorin III is needed for normal patterning and growth of nerves, bones and heart.

    PubMed

    Behar, O; Golden, J A; Mashimo, H; Schoen, F J; Fishman, M C

    1996-10-10

    The expression patterns of the recently discovered family of semaphorin genes suggests that they have widespread roles in embryonic development. Some seem to guide neuronal growth cones, but otherwise their functions are unknown. Semaphorin III is a membrane-associated secreted protein with a developmentally dynamic pattern of expression, including particular domains of the nervous system, the borders of developing bones, and the heart. In vitro, semaphorin III causes growth-cone collapse, and repels cutaneous sensory axons from the ventral spinal cord. Mutants in the Drosophila gene semaII, which encodes a related semaphorin, die after eclosion, but no responsible abnormality is evident. We have generated mice mutant in the semaIII gene by homologous recombination. Here we show that in the mutants, some sensory axons project into inappropriate regions of the spinal cord where semaIII is normally expressed. The cerebral cortex of homozygous mutant mice shows a paucity of neuropil and abnormally oriented neuronal processes, especially of the large pyramidal neurons. Certain embryonic bones and cartilaginous structures develop abnormally, with vertebral fusions and partial rib duplications. The few mice that survive more than a few days postnatally manifest pronounced and selective hypertrophy of the right ventricle of the heart and dilation of the right atrium. Thus, semaphorin III might serve as a signal that restrains growth in several developing organs.

  4. Mathematical modelling of cancer invasion: implications of cell adhesion variability for tumour infiltrative growth patterns.

    PubMed

    Domschke, Pia; Trucu, Dumitru; Gerisch, Alf; A J Chaplain, Mark

    2014-11-21

    Cancer invasion, recognised as one of the hallmarks of cancer, is a complex, multiscale phenomenon involving many inter-related genetic, biochemical, cellular and tissue processes at different spatial and temporal scales. Central to invasion is the ability of cancer cells to alter and degrade an extracellular matrix. Combined with abnormal excessive proliferation and migration which is enabled and enhanced by altered cell-cell and cell-matrix adhesion, the cancerous mass can invade the neighbouring tissue. Along with tumour-induced angiogenesis, invasion is a key component of metastatic spread, ultimately leading to the formation of secondary tumours in other parts of the host body. In this paper we explore the spatio-temporal dynamics of a model of cancer invasion, where cell-cell and cell-matrix adhesion is accounted for through non-local interaction terms in a system of partial integro-differential equations. The change of adhesion properties during cancer growth and development is investigated here through time-dependent adhesion characteristics within the cell population as well as those between the cells and the components of the extracellular matrix. Our computational simulation results demonstrate a range of heterogeneous dynamics which are qualitatively similar to the invasive growth patterns observed in a number of different types of cancer, such as tumour infiltrative growth patterns (INF). Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Growth of high quality germanium films on patterned silicon substrates and applications

    NASA Astrophysics Data System (ADS)

    Vanamu, Ganesh

    The principal objective of this work is to determine optimal pattern structures for highest quality (defect free) heteroepitaxial growth. High quality films of Ge on Si are of significant importance and can be used in high electron mobility devices, photodetectors for optical communications (1.3mum or 1.55mum) and integrating III-V optoelectronic devices. However, a 4% lattice mismatch and ˜ 50% thermal expansion mismatch between Ge and Si create three major challenges in growing high quality Ge films on Si, (a) high surface roughness due to a pronounced <110> crosshatch pattern, (b) high dislocation densities in Ge films and (c) high density of microcracks and wafer bending. A common way of reducing lattice and thermal expansion mismatch is to form a "virtual substrate (VS)" by growing a graded composition followed by a uniform layer of the desired epitaxial film on a defect-free Si substrate. Virtual graded layers could not decrease the dislocation densities to the numbers acceptable for most of the devices. Mathews et al. first proposed that limiting the lateral dimensions of the sample prior to growth could reduce the dislocation density. Later On Fitzgerald proposed that patterning decreases the dislocation density in the films. In this work we show high quality crosshatch-free Ge films with dislocation density ˜ 105 cm-2 on the nano-patterned Si and also high quality GaAs films on the Ge/Si virtual substrate. The first step in this research was to perform a systematic study to identify the role of pattern width on the quality of Ge growth. We investigated micrometer and submicrometer scale patterns. We demonstrated that the quality of the heteroepitaxial layers improves as the pattern width decreases. Then we have decreased the pattern width to nanometer-scale dimensions. Significant improvement of the Ge film quality was observed. We used novel interferometric lithography techniques combined with reactive ion and wet chemical etching to fabricate Si

  6. Pattern of growth and adiposity from infancy to adulthood in atopic dermatitis.

    PubMed

    Ellison, J A; Patel, L; Kecojevic, T; Foster, P J; David, T J; Clayton, P E

    2006-09-01

    Impaired linear growth has been reported in children with atopic dermatitis (AD) but the pattern of growth in height and weight through childhood and adolescence has not been described. To define the pattern of linear growth and adiposity in AD from early childhood through to adult life. Growth measurements of 70 male and 40 female patients with AD followed through childhood and adolescence were studied retrospectively and compared with the 1990 U.K. normal values. Height, weight and body mass index (BMI) were converted to standard deviation scores (SDS). Regression analysis examined whether the mean trend was different from zero. While dermatitis was the predominant atopic problem in all 110 patients, 92 had a history of asthma which was mild in 85 of 92. Regression analyses showed that the trends in height, weight and BMI SDS for AD patients were significantly different from zero and also different between males and females. Both sexes were short and relatively overweight from early childhood, a trend that was more pronounced in males than females. At 5 years (school entry), the 50th centile BMI of male (but not female) patients was 0.44 kg m(-2) higher than the reference population but height and weight were lower. The age at adiposity rebound in AD males and females was 0.8 year and 0.7 year later than the U.K. population (6.2 years vs. 5.4 years and 6.2 years vs. 5.3 years, respectively). AD patients attained peak height velocity later than the 1990 U.K. population (males 16.0 years vs. 13.5 years, P = 0.0002; females 13.4 years vs. 11.0 years, P = 0.008). In addition, males had greater mean gain in height during late adolescence (12.2 vs. 8.8 cm, P = 0.03) and were shorter as young adults (170.9 vs. 177.6 cm, P = 0.0005). Our patients with AD were relatively overweight very early but had a later adiposity rebound, were short in childhood and had a delayed adolescent growth spurt. Serial growth measurements should be done on all children with troublesome AD

  7. Growth patterns among HIV-exposed infants receiving nevirapine prophylaxis in Pune, India.

    PubMed

    Ram, Malathi; Gupte, Nikhil; Nayak, Uma; Kinikar, Aarti A; Khandave, Mangesh; Shankar, Anita V; Sastry, Jayagowri; Bollinger, Robert C; Gupta, Amita

    2012-10-31

    India has among the highest rates of infant malnutrition. Few studies investigating the growth patterns of HIV-exposed infants in India or the impact of timing of HIV infection on growth in settings such as India exist. We used data from the Six Week Extended Nevirapine (SWEN) trial to compare the growth patterns of HIV-infected and HIV-exposed but uninfected infants accounting for timing of HIV infection, and to identify risk factors for stunting, underweight and wasting. Growth and timing of HIV infection were assessed at weeks 1, 2, 4, 6, 10, 14 weeks and 6, 9, 12 months of life. Random effects multivariable logistic regression method was used to assess factors associated with stunting, underweight and wasting. Among 737 HIV-exposed infants, 93 (13%) were HIV-infected by 12 months of age. Among HIV-infected and uninfected infants, baseline prevalence of stunting (48% vs. 46%), underweight (27% vs. 26%) and wasting (7% vs. 11%) was similar (p>0.29), but by 12 months stunting and underweight, but not wasting, were significantly higher in HIV-infected infants (80% vs. 56%, 52% vs. 29%, p< 0.0001; 5% vs. 6%, p=0.65, respectively). These differences rapidly manifested within 4-6 weeks of birth. Infants infected in utero had the worst growth outcomes during the follow-up period. SWEN was associated with non-significant reductions in stunting and underweight among HIV-infected infants and significantly less wasting in HIV-uninfected infants. In multivariate analysis, maternal CD4 < 250, infant HIV status, less breastfeeding, low birth weight, non-vaginal delivery, and infant gestational age were significant risk factors for underweight and stunting. Baseline stunting and underweight was high in both HIV-infected and uninfected infants; growth indices diverged early and were impacted by timing of infection and SWEN prophylaxis. Early growth monitoring of all HIV-exposed infants is an important low-cost strategy for improving health and survival outcomes of these infants

  8. Molecular characterization and expression patterns of myogenin in compensatory growth of Megalobrama amblycephala.

    PubMed

    Zhu, Kecheng; Chen, Liping; Zhao, Jinkun; Wang, Huijuan; Wang, Weimin; Li, Zhong; Wang, Huanling

    2014-04-01

    Myogenin (myog) is a muscle-specific basic helix-loop-helix (bHLH) transcription factor that plays an essential role in regulating skeletal muscle development and growth. To investigate molecular characterization of myog and the effect of starvation/refeeding on the gene expression, we isolated the myog cDNA sequence and analyzed the expression patterns using quantitative real-time polymerase chain reaction in Megalobrama amblycephala. Sequence analysis indicated that M. amblycephala myog shared an analogous structure with the highly conserved His/Cys-rich, bHLH and C-terminal helix III domains with other vertebrates. Sequence alignment and phylogenetic tree showed that M. amblycephala myog had the highest identity with the homologues of Ctenopharyngodon idella and Cyprinus carpio. Spatio-temporal expression patterns revealed that myog mRNA levels at the segmentation period and 12 h post-hatching (hph) were significantly higher than at other development stages (P<0.05). Furthermore, the highest myog expression level was predominantly observed in white muscle compared with the other types of muscle. Fish body weight continuously decreased during 21-day starvation and then significantly increased after 7days of refeeding and reached the similar level to the control at 21days of refeeding, indicating that the pattern of complete compensatory growth possibly occurred in M. amblycephala; meanwhile, the relative somatic growth rate after refeeding was also dramatically higher than the control group. In addition, the myog expression decreased during 21days of starvation and then exhibited a strong rebound effect after 7days of refeeding and subsequently declined gradually to the control level by 21days of refeeding.

  9. Patterned Growth of Organic Semiconductors: Selective Nucleation of Perylene on Self-Assembled Monolayers.

    PubMed

    Pick, André; Witte, Gregor

    2016-08-16

    Organic semiconductors (OSC) have received a large amount of attention because they afford the fabrication of flexible electronic devices. However, the limited resistance to radiation and etching of such materials does not permit their patterning by photolithography, which has been a driving force for the development of integrated circuits and therefore requires alternative structuring techniques. One approach is based on precoating the substrate with self-assembled monolayers (SAMs) to control the nucleation of subsequently deposited OSC layers, but the underlying mechanism is barely understood. Here, we used alkanethiols with different chemical terminations to prepare SAMs on gold substrates serving as model systems to identify the mechanism of selective nucleation for the case of the OSC perylene. Using atomic force microscopy and fluorescence microscopy, we demonstrate that the chemical functionalization of the SAMs determines the adhesion forces for the OSC that are smallest for CF3-terminated and largest for OH-terminated SAMs, hence yielding distinctly different sticking probabilities upon perylene deposition at room temperature. Microcontact printing and immersion were employed to prepare SAM patterns that enable the selective growth of polycrystalline perylene films. A quite different situation is found upon printing long-chain thiols with low vapor pressure, which leads to the transfer of multilayers and favors the growth of perylene single crystallites. In a more abstract scenario, patterns of silicone oil droplets were printed on a gold substrate, which was previously covered with a repelling fluorinated SAM. Such droplets provide nucleation centers for liquid-mediated growth, often yielding platelet-shaped perylene single crystallites without unwanted perylene nucleation on the remaining surface.

  10. Simulation of Epitaxial Growth of DNA-nanoparticle Superlattices on Pre-patterned Substrates

    NASA Astrophysics Data System (ADS)

    Pan, Saijie; Li, Ting; Olvera de La Cruz, Monica

    2015-03-01

    DNA self-assembly is a well-developed approach towards the construction of a great variety of nanoarchitectures. E-beam lithography is widely used for high-resolution nanoscale patterning. Recently, a new technique combining the two methods was developed to epitaxially grow DNA-mediated nanoparticle superlattices on a pre-patterned surface. Here we use multi-scale simulations to study and predict the formation and defects of the absorbed superlattice monolayer. We demonstrate that the epitaxial growth is enthalpy driven and show that the anisotropy of the DNA-mediated substrates leads to structure defects. We develop design rules to dramatically reduce defects of the attached layer. Ultimately, with the assist of our simulation, this technique will open the door for the construction of well-ordered, three-dimensional novel metamaterials. This work was supported by the the Air Force Office of Scientific Research (AFOSR) Multidisciplinary University Research Initiative (MURI) FA9550-11-1-0275.

  11. Patterning nanofibrils through the templated growth of multiple modified amyloid peptides

    PubMed Central

    Sakai, Hiroki; Watanabe, Ken; Kudoh, Fuki; Kamada, Rui; Chuman, Yoshiro; Sakaguchi, Kazuyasu

    2016-01-01

    There has been considerable interest in the patterning of functionalized nanowires because of the potential applications of these materials to the construction of nanodevices. A variety of biomolecular building blocks containing amyloid peptides have been used to functionalize nanowires. However, the patterning of self-assembled nanowires can be challenging because of the difficulties associated with controlling the self-assembly of these functionalized building blocks. Herein, we present a versatile approach for the patterning of nanowires based on the combination of templated fibril growth with a versatile functionalization method using our structure-controllable amyloid peptides (SCAPs). Using this approach, we have succeeded in the formation of multi-type nanowires with tandem domain structures in high yields. Given that the mixing-SCAP method can lead to the formation of tandem fibrils, it is noteworthy that our method allowed us to control the initiation of fibril formation from the gold nanoparticles, which were attached to a short fibril as initiation points. This approach could be used to prepare a wide variety of fibril patterns, and therefore holds great potential for the development of novel self-assembled nanodevices. PMID:27559011

  12. Metalorganic molecular beam epitaxy growth of GaAs on patterned GaAs substrates

    NASA Astrophysics Data System (ADS)

    Marx, D.; Asahi, H.; Liu, X. F.; Okuno, Y.; Inoue, K.; Gonda, S.; Shimomura, S.; Hiyamizu, S.

    1994-03-01

    GaAs layers were grown on etch-patterned (100) GaAs substrates by MOMBE (metalorganic molecular beam epitaxy) using TEGa (triethylgallium) and thermally cracked TEAs (triethylarsine). Morphology and orientation dependencies of the grown facets on the growth temperature (400-630°C) and V/III ratio (2-4) are investigated. Good morphology of grown layers was obtained on (111)A side facets at a low V/III ratio of 3 and low growth temperatures of 450-500°C. We also found strong evidence that the formation of facets is not only governed by the migration of Ga precursors and/or Ga atoms, but also by a preferential catalytic decomposition of Ga precursors on the facet edges.

  13. Monitoring of Water Spectral Pattern Reveals Differences in Probiotics Growth When Used for Rapid Bacteria Selection.

    PubMed

    Slavchev, Aleksandar; Kovacs, Zoltan; Koshiba, Haruki; Nagai, Airi; Bázár, György; Krastanov, Albert; Kubota, Yousuke; Tsenkova, Roumiana

    2015-01-01

    Development of efficient screening method coupled with cell functionality evaluation is highly needed in contemporary microbiology. The presented novel concept and fast non-destructive method brings in to play the water spectral pattern of the solution as a molecular fingerprint of the cell culture system. To elucidate the concept, NIR spectroscopy with Aquaphotomics were applied to monitor the growth of sixteen Lactobacillus bulgaricus one Lactobacillus pentosus and one Lactobacillus gasseri bacteria strains. Their growth rate, maximal optical density, low pH and bile tolerances were measured and further used as a reference data for analysis of the simultaneously acquired spectral data. The acquired spectral data in the region of 1100-1850nm was subjected to various multivariate data analyses - PCA, OPLS-DA, PLSR. The results showed high accuracy of bacteria strains classification according to their probiotic strength. Most informative spectral fingerprints covered the first overtone of water, emphasizing the relation of water molecular system to cell functionality.

  14. Digital Transfer Growth of Patterned 2D Metal Chalcogenides by Confined Nanoparticle Evaporation

    DOE PAGES

    Mahjouri-Samani, Masoud; Tian, Mengkun; Wang, Kai; ...

    2014-10-19

    Developing methods for the facile synthesis of two-dimensional (2D) metal chalcogenides and other layered materials is crucial for emerging applications in functional devices. Controlling the stoichiometry, number of the layers, crystallite size, growth location, and areal uniformity is challenging in conventional vapor phase synthesis. Here, we demonstrate a new route to control these parameters in the growth of metal chalcogenide (GaSe) and dichalcogenide (MoSe2) 2D crystals by precisely defining the mass and location of the source materials in a confined transfer growth system. A uniform and precise amount of stoichiometric nanoparticles are first synthesized and deposited onto a substrate bymore » pulsed laser deposition (PLD) at room temperature. This source substrate is then covered with a receiver substrate to form a confined vapor transport growth (VTG) system. By simply heating the source substrate in an inert background gas, a natural temperature gradient is formed that evaporates the confined nanoparticles to grow large, crystalline 2D nanosheets on the cooler receiver substrate, the temperature of which is controlled by the background gas pressure. Large monolayer crystalline domains (~ 100 m lateral sizes) of GaSe and MoSe2 are demonstrated, as well as continuous monolayer films through the deposition of additional precursor materials. This novel PLD-VTG synthesis and processing method offers a unique approach for the controlled growth of large-area, metal chalcogenides with a controlled number of layers in patterned growth locations for optoelectronics and energy related applications.« less

  15. Volume Changes After Stereotactic LINAC Radiotherapy in Vestibular Schwannoma: Control Rate and Growth Patterns

    SciTech Connect

    Langenberg, Rick van de; Dohmen, Amy J.C.; Bondt, Bert J. de; Nelemans, Patty J.; Baumert, Brigitta G.; Stokroos, Robert J.

    2012-10-01

    Purpose: The purpose of this study was to evaluate the control rate of vestibular schwannomas (VS) after treatment with linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) or radiotherapy (SRT) by using a validated volumetric measuring tool. Volume-based studies on prognosis after LINAC-based SRS or SRT for VS are reported scarcely. In addition, growth patterns and risk factors predicting treatment failure were analyzed. Materials and Methods: Retrospectively, 37 VS patients treated with LINAC based SRS or SRT were analyzed. Baseline and follow-up magnetic resonance imaging scans were analyzed with volume measurements on contrast enhanced T1-weighted magnetic resonance imaging. Absence of intervention after radiotherapy was defined as 'no additional intervention group, ' absence of radiological growth was defined as 'radiological control group. ' Significant growth was defined as a volume change of 19.7% or more, as calculated in a previous study. Results: The cumulative 4-year probability of no additional intervention was 96.4% {+-} 0.03; the 4-year radiological control probability was 85.4% {+-} 0.1). The median follow-up was 40 months. Overall, shrinkage was seen in 65%, stable VS in 22%, and growth in 13%. In 54% of all patients, transient swelling was observed. No prognostic factors were found regarding VS growth. Previous treatment and SRS were associated with transient swelling significantly. Conclusions: Good control rates are reported for LINAC based SRS or SRT in VS, in which the lower rate of radiological growth control is attributed to the use of the more sensitive volume measurements. Transient swelling after radiosurgery is a common phenomenon and should not be mistaken for treatment failure. Previous treatment and SRS were significantly associated with transient swelling.

  16. Urban vegetation and thermal patterns following city growth in different socio-economic contexts

    NASA Astrophysics Data System (ADS)

    Dronova, I.; Clinton, N.; Yang, J.; Radke, J.; Marx, S. S.; Gong, P.

    2015-12-01

    Urban expansion accompanied by losses of vegetated spaces and their ecological services raises significant concerns about the future of humans in metropolitan "habitats". Despite recent growth of urban studies globally, it is still not well understood how environmental effects of urbanization vary with the rate and socioeconomic context of development. Our study hypothesized that with urban development, spatial patterns of surface thermal properties and green plant cover would shift towards higher occurrence of relatively warmer and less vegetated spaces such as built-up areas, followed by losses of greener and cooler areas such as urban forests, and that these shifts would be more pronounced with higher rate of economic and/or population growth. To test these ideas, we compared 1992-2011 changes in remotely sensed patterns of green vegetation and surface temperature in three example cities that experienced peripheral growth under contrasting socio-economic context - Dallas, TX, USA, Beijing, China and Kyiv, Ukraine. To assess their transformation, we proposed a metric of thermal-vegetation angle (TVA) estimated from per-pixel proxies of vegetation greenness and surface temperature from Landsat satellite data and examined changes in TVA distributions within each city's core and two decadal zones of peripheral sprawl delineated from nighttime satellite data. We found that higher economic and population growth were coupled with more pronounced changes in TVA distributions, and more urbanized zones often exhibited higher frequencies of warmer, less green than average TVA values with novel patterns such as "cooler" clusters of building shadows. Although greener and cooler spaces generally diminished with development, they remained relatively prevalent in low-density residential areas of Dallas and peripheral zones of Kyiv with exurban subsistence farming. Overall, results indicate that the effects of modified green space and thermal patterns within growing cities

  17. Modeling growth, coalescence, and stability of helium precipitates on patterned interfaces

    NASA Astrophysics Data System (ADS)

    Yuryev, D. V.; Demkowicz, M. J.

    2017-01-01

    We develop a phase field simulation to model morphology evolution of helium (He) precipitates on solid-state interfaces. Our approach accounts for differences in precipitate contact angles arising from location-dependent interface energies and is capable of describing precipitate growth, coalescence, and de-wetting from the interface. We demonstrate our approach for interfaces with linear chains of wettable patches and find that different wetting energies and patch spacings give rise to four distinct classes of helium precipitate morphologies. Our method may be adapted to other scenarios involving fluids precipitating on non-uniform solid-state interfaces as well as to precipitation on patterned surfaces.

  18. Patterns of dynamic urban population growth in Russia, 1989-1996: a research report.

    PubMed

    Rowland, R H

    1997-01-01

    "The purpose of this paper is to investigate locations in which rapid urban growth occurred in Russia over the period 1989 to 1996....Particular emphasis will be given to the geographical patterns, economic functions, and population size of rapidly growing towns. In addition, the discussion of trends for 1989-1996 also will be briefly preceded by and compared to those of 1979-1989, although the paper will emphasize trends during the 1990s. Furthermore, the topic of ¿new towns', which themselves often are rapidly growing centers, will be addressed as well."

  19. Cell-Type Dependent Effect of Surface-Patterned Microdot Arrays on Neuronal Growth

    PubMed Central

    Jang, Min Jee; Kim, Woon Ryoung; Joo, Sunghoon; Ryu, Jae Ryun; Lee, Eunsoo; Nam, Yoonkey; Sun, Woong

    2016-01-01

    Surface micropatterns have been widely used as chemical cues to control the microenvironment of cultured neurons, particularly for neurobiological assays and neurochip designs. However, the cell-type dependency on the interactions between neurons and underlying micropatterns has been rarely investigated despite the inherent differences in the morphology of neuronal types. In this study, we used surface-printed microdot arrays to investigate the effect of the same micropatterns on the growth of mouse spinal interneuron, mouse hippocampal neurons, and rat hippocampal neurons. While mouse hippocampal neurons showed no significantly different growth on control and patterned substrates, we found the microdot arrays had different effects on early neuronal growth depending on the cell type; spinal interneurons tended to grow faster in length, whereas hippocampal neurons tended to form more axon collateral branches in response to the microdot arrays. Although there was a similar trend in the neurite length and branch number of both neurons changed across the microdot arrays with the expanded range of size and spacing, the dominant responses of each neuron, neurite elongation of mouse spinal interneurons and branching augmentation of rat hippocampal neurons were still preserved. Therefore, our results demonstrate that the same design of micropatterns could cause different neuronal growth results, raising an intriguing issue of considering cell types in neural interface designs. PMID:27242421

  20. Growth patterns of Chromolaena odorata in varied ecosystems at Kodayar in the Western Ghats, India

    NASA Astrophysics Data System (ADS)

    Chandrasekaran, Sivagnanam; Swamy, P. S.

    2010-07-01

    The growth and allocation patterns of biomass and nutrients (nitrogen, phosphorus and potassium) were studied in Chromolaena odorata populations grown in different human modified ecosystems including an Albizia plantation, a rubber plantation, community land and a naturally regenerating forest. The greater shoot length of C. odorata in the regenerating forest could be attributed to the competitive and shady environment created by the mature vegetation here. High relative growth rate, net assimilation rate and reproductive potential of C. odorata populations growing on the community land and in the rubber plantation may be due to the open habitat and frequent disturbances to these sites. In general, allocation of biomass and nutrients to the leaf and reproductive components was low in the regenerating forest. On the other hand, greater allocation to the root component in the regenerating forest may be a strategy for survival and regeneration after the disturbance. Low nutrient uptake and greater resource use efficiency in the regenerating forest could be a response to limited resource availability under the competitive micro-environment created by the fast growing tree species. C. odorata has an exploitative growth strategy and will persist in regenerating open habitats whereas it showed suppressed growth in the light - limited shaded environment.

  1. ANGUSTIFOLIA mediates one of the multiple SCRAMBLED signaling pathways regulating cell growth pattern in Arabidopsis thaliana.

    PubMed

    Kwak, Su-Hwan; Song, Sang-Kee; Lee, Myeong Min; Schiefelbein, John

    2015-09-25

    In Arabidopsis thaliana, an atypical leucine-rich repeat receptor-like kinase, SCRAMBLED (SCM), is required for multiple developmental processes including root epidermal cell fate determination, silique dehiscence, inflorescence growth, ovule morphogenesis, and tissue morphology. Previous work suggested that SCM regulates these multiple pathways using distinct mechanisms via interactions with specific downstream factors. ANGUSTIFOLIA (AN) is known to regulate cell and tissue morphogenesis by influencing cortical microtubule arrangement, and recently, the AN protein was reported to interact with the SCM protein. Therefore, we examined whether AN might be responsible for mediating some of the SCM-dependent phenotypes. We discovered that both scm and an mutant lines cause an abnormal spiral or twisting growth of roots, but only the scm mutant affected root epidermal patterning. The siliques of the an and scm mutants also exhibited spiral growth, as previously reported, but only the scm mutant altered silique dehiscence. Interestingly, we discovered that the spiral growth of roots and siliques of the scm mutant is rescued by a truncated SCM protein that lacks its kinase domain, and that a juxtamembrane domain of SCM was sufficient for AN binding in the yeast two-hybrid analysis. These results suggest that the AN protein is one of the critical downstream factors of SCM pathways specifically responsible for mediating its effects on cell/tissue morphogenesis through cortical microtubule arrangement.

  2. Temperature dependent growth rates of the upper-hybrid waves and solar radio zebra patterns

    NASA Astrophysics Data System (ADS)

    Benáček, J.; Karlický, M.; Yasnov, L. V.

    2017-02-01

    Context. The zebra patterns observed in solar radio emission are very important for flare plasma diagnostics. The most promising model of these patterns is based on double plasma resonance instability, which generates upper-hybrid waves, which can be then transformed into the zebra emission. Aims: We aim to study in detail the double plasma resonance instability of hot electrons, together with a much denser thermal background plasma. In particular, we analyse how the growth rate of the instability depends on the temperature of both the hot plasma and background plasma components. Methods: We numerically integrated the analysed model equations, using Python and Wolfram Mathematica. Results: We found that the growth-rate maxima of the upper-hybrid waves for non-zero temperatures of both the hot and background plasma are shifted towards lower frequencies comparing to the zero temperature case. This shift increases with an increase of the harmonic number s of the electron cyclotron frequency and temperatures of both hot and background plasma components. We show how this shift changes values of the magnetic field strength estimated from observed zebras. We confirmed that for a relatively low hot electron temperature, the dependence of growth rate vs. both the ratio of the electron plasma and electron cyclotron frequencies expresse distinct peaks, and by increasing this temperature these peaks become smoothed. We found that in some cases, the values of wave number vector components for the upper-hybrid wave for the maximal growth rate strongly deviate from their analytical estimations. We confirmed the validity of the assumptions used when deriving model equations.

  3. The effects of altered maxillary growth on patterns of mandibular rotation in a pig model.

    PubMed

    Holton, Nathan E; Nicholas, Christina L; Marshall, Steve D; Franciscus, Robert G; Southard, Thomas E

    2015-06-01

    A thorough understanding of influence of maxillary growth on patterns of mandibular rotation during development is important with regard to the treatment of skeletal discrepancies. In the present study, we examined whether experimentally altered maxillary position has a significant influence on patterns of mandibular rotation in a pig model. Maxillary growth was altered in a sample of n=10 domestic pigs via surgical fixation of the circummaxillary sutures. We compared the experimental group to control and surgical sham samples and assessed the effects of altered maxillary growth on mandibular form using geometric morphometric techniques. We tested for significant differences in mandibular shape between our samples and examined axes of morphological variation. Additionally, we examined whether altered mandibular shape resulting from altered maxillary position was predictably associated with morphological changes to the condylar region. There was a statistically significant difference in mandibular shape between the experimental and control/sham groups. As a result of vertical displacement of the snout, mandibles in the experimental sample resulted in greater anterior rotation when compared to the control/sham pigs. Variation in rotation was correlated with morphological changes in the condyle including the shape of the articular surface and condylar orientation indicative of greater anterior mandibular rotation. Vertical displacement of the maxilla had a significant effect on mandibular shape by encouraging anterior mandibular rotation. This result has important implications for understanding the effects of altered mandibular posture on condylar remodeling the treatment of skeletal discrepancies such as the correction of hyperdivegent mandibular growth. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. [Growth and resource allocation pattern of Artemisia frigida under different grazing and clipping intensities].

    PubMed

    Li, Jinhua; Li, Zhenqing; Liu, Zhenguo

    2004-03-01

    In order to understand the degradation process and its mechanism of typical steppe in Inner Mongolia, this paper studied the growth and resource allocation pattern of Artimisia frigida under different grazing and clipping intensities(no grazing, light grazing 1.33 sheep.hm-2, moderate grazing 4.00 sheep.hm-2, heavy grazing 6.67 sheep.hm-2, proportional clipping and stubble clipping), which was conducted at the Inner Mongolia Grassland Ecosystem Research Station of Chinese Academy of Sciences(43 degrees 26'-44 degrees 08' N, 116 degrees 04'-117 degrees 05' E). The results showed that the regrowth ability of A. frigida under proportional clipping was superior to that under stubble clipping, and light clipping (1/4 proportional clipping or 10 cm stubble clipping) was superior to no clipping. In early growth season, the net regrowth of A. frigida was higher under no clipping than under light clipping, but reversed in late growth season (after mid-August). The biomass allocation pattern of A. frigida was roots > leaves > stems. Grazing or clipping affected biomass allocation significantly, especially for the allocation of leaves and flowers. The biomass allocation of leaves was significantly higher under 3/4 proportional clipping or 4 cm stubble clipping than under other treatments, and reverse trend was true for the biomass allocation of flowers. There were no significant differences in biomass allocation of roots and stems among treatments. Sexual reproductive allocation decreased with increasing grazing or clipping intensities, and reproductive mode of A. frigida changed under heavy grazing. The changes in priority of biomass allocation from sexual reproductive organs to clonal growth to sustain and propagate population were important ecological strategies of the species to heavy grazing.

  5. Retrieving clinical evidence: a comparison of PubMed and Google Scholar for quick clinical searches.

    PubMed

    Shariff, Salimah Z; Bejaimal, Shayna Ad; Sontrop, Jessica M; Iansavichus, Arthur V; Haynes, R Brian; Weir, Matthew A; Garg, Amit X

    2013-08-15

    Physicians frequently search PubMed for information to guide patient care. More recently, Google Scholar has gained popularity as another freely accessible bibliographic database. To compare the performance of searches in PubMed and Google Scholar. We surveyed nephrologists (kidney specialists) and provided each with a unique clinical question derived from 100 renal therapy systematic reviews. Each physician provided the search terms they would type into a bibliographic database to locate evidence to answer the clinical question. We executed each of these searches in PubMed and Google Scholar and compared results for the first 40 records retrieved (equivalent to 2 default search pages in PubMed). We evaluated the recall (proportion of relevant articles found) and precision (ratio of relevant to nonrelevant articles) of the searches performed in PubMed and Google Scholar. Primary studies included in the systematic reviews served as the reference standard for relevant articles. We further documented whether relevant articles were available as free full-texts. Compared with PubMed, the average search in Google Scholar retrieved twice as many relevant articles (PubMed: 11%; Google Scholar: 22%; P<.001). Precision was similar in both databases (PubMed: 6%; Google Scholar: 8%; P=.07). Google Scholar provided significantly greater access to free full-text publications (PubMed: 5%; Google Scholar: 14%; P<.001). For quick clinical searches, Google Scholar returns twice as many relevant articles as PubMed and provides greater access to free full-text articles.

  6. Response to long-term growth hormone therapy in patients affected by RASopathies and growth hormone deficiency: Patterns of growth, puberty and final height data.

    PubMed

    Tamburrino, Federica; Gibertoni, Dino; Rossi, Cesare; Scarano, Emanuela; Perri, Annamaria; Montanari, Francesca; Fantini, Maria Pia; Pession, Andrea; Tartaglia, Marco; Mazzanti, Laura

    2015-11-01

    RASopathies are developmental disorders caused by heterozygous germline mutations in genes encoding proteins in the RAS-MAPK signaling pathway. Reduced growth is a common feature. Several studies generated data on growth, final height (FH), and height velocity (HV) after growth hormone (GH) treatment in patients with these disorders, particularly in Noonan syndrome, the most common RASopathy. These studies, however, refer to heterogeneous cohorts in terms of molecular information, GH status, age at start and length of therapy, and GH dosage. This work reports growth data in 88 patients affected by RASopathies with molecularly confirmed diagnosis, together with statistics on body proportions, pubertal pattern, and FH in 33, including 16 treated with GH therapy for proven GH deficiency. Thirty-three patients showed GH deficiency after pharmacological tests, and were GH-treated for an average period of 6.8 ± 4.8 years. Before starting therapy, HV was -2.6 ± 1.3 SDS, and mean basal IGF1 levels were -2.0 ± 1.1 SDS. Long-term GH therapy, starting early during childhood, resulted in a positive height response compared with untreated patients (1.3 SDS in terms of height-gain), normalizing FH for Ranke standards but not for general population and Target Height. Pubertal timing negatively affected pubertal growth spurt and FH, with IGF1 standardized score increased from -2.43 to -0.27 SDS. During GH treatment, no significant change in bone age velocity, body proportions, or cardiovascular function was observed.

  7. Facet growth of self-separated GaN layers through HVPE on large square-patterned template

    NASA Astrophysics Data System (ADS)

    Sui, Yanping; Wang, Bin; Zhao, Zhide; Xu, Wei; Li, Xiaoliang; Wang, Xinzhong; Yu, Guanghui

    2014-05-01

    A self-separated GaN layer was prepared by hydride vapor phase epitaxy (HVPE) on a square-patterned template with large periodicity. Self-separation was completed by breakage of the fragile layer because of the thermal stresses generated during the cooling process after HVPE growth. The GaN layer exhibited graphical surface comprising the terrace and the concave, the shapes of which were corresponding with the mask pattern. The terrace came from the growth on window openings, and had Ga-polarity by wet etching and micro-Raman measurement. The concave over the mask was composed of large inclined facets, and was demonstrated to have N-polarity. The growth on large square-patterned template was considered to be facet growth. The polarity inversion was related to dislocation accumulation. The strain distribution regularly varied, which was interpreted based on the facet growth mode.

  8. Inter-cohort growth patterns of pharaoh cuttlefish Sepia pharaonis (Sepioidea: Sepiidae) in Eastern Arabian Sea.

    PubMed

    Sasikumarl, Geetha; Mohamed, K S; Bhat, U S

    2013-03-01

    Sepia pharaonis is an important commercial species endemic to the tropical Indo-Pacific region. Despite its commercial significance, only few information on natural populations is available. This study was aimed to describe the aspects of size-composition, length-weight relationship, catch rates, seasonal recruitment and inter-cohort growth patterns of S. pharaonis population (Clade C), distributed along the Eastern Arabian Sea (South-West coast of India). For this, the Dorsal Mantle Length (DML) and weight of cuttlefishes was obtained from commercial trawl catches, from April 2002 to October 2006. Data was analyzed by normal length-weight methods such as von Bertalanffy. A total of 12454 cuttlefishes, ranging in length from four to 41cm were analyzed. Size-composition patterns discriminated two pulses in recruitment to the fishery, discernible by a decrease in the monthly mean size of the population. The DMLs of the two seasonal cohorts were subjected to modal-progression analysis using the Bhattacharya's method for the estimation of growth. The estimated parameters Linfinity and K in von Bertalanffy Growth Function (VBGF) were used to model growth curves in length for the cohorts. The first cohort, (post-monsoon cohort) which supports the major fishery, was composed of medium-sized, fast growing individuals, whereas the second cohort (pre-monsoon cohort), comprised of slow growing and large-sized individuals. There were differential growth characteristics between the sexes and the life span was estimated at less than 2.3 years for males and 2.1 years for females. Negative allometric growth in weight (W) with length (L) was observed for males (W=0.33069.L2.5389) and females (W=0.32542.L26057). The females were heavier compared to males at any given mantle length, and the males were found to attain larger ultimate lengths. The major fishing season for cuttlefish was from May to November, when higher monthly catch rates of 1.67-13.02kg/h were observed in comparison

  9. Differential in vitro phenotype pattern, transforming growth factor-beta(1) activity and mRNA expression of transforming growth factor-beta(1) in Apert osteoblasts.

    PubMed

    Locci, P; Baroni, T; Pezzetti, F; Lilli, C; Marinucci, L; Martinese, D; Becchetti, E; Calvitti, M; Carinci, F

    1999-09-01

    The phenotype of Apert osteoblasts differs from that of normal osteoblasts in the accumulation of macromolecules in the extracellular matrix. Apert osteoblasts increase type I collagen, fibronectin and glycosaminoglycans secretion compared with normal osteoblasts. Because the extracellular matrix macromolecule accumulation is greatly modulated by transforming growth factor-beta(1), we examined the ability of normal and Apert osteoblasts to secrete transforming growth factor-beta(1) by CCL-64 assay and to produce transforming growth factor-beta(1 )by analysis of the mRNA expression of transforming growth factor-beta(1). Northern blot analysis revealed an increased amount of transforming growth factor-beta(1) mRNA expression in Apert osteoblasts compared with normal ones. Moreover, the level of the active transforming growth factor-beta(1) isoform was higher in Apert than in normal media. In pathologic cells, the increase in transforming growth factor-beta(1) gene expression was associated with a parallel increase in the factor secreted into the medium. The level of transforming growth factor-beta(1) was decreased by the addition of basic fibroblast growth factor. Transforming growth factor-beta(1) is controlled temporally and spatially during skeletal tissue development and produces complex stimulatory and inhibitory changes in osteoblast functions. We hypothesise that in vitro differences between normal and Apert osteoblasts may be correlated to different transforming growth factor-beta(1) cascade patterns, probably due to an altered balance between transforming growth factor-beta(1) and basic fibroblast growth factor.

  10. Age- and sex-related growth patterns of the craniofacial complex in European children aged 3-6 years.

    PubMed

    Tutkuviene, Janina; Cattaneo, Cristina; Obertová, Zuzana; Ratnayake, Melanie; Poppa, Pasquale; Barkus, Arunas; Khalaj-Hedayati, Kerstin; Schroeder, Inge; Ritz-Timme, Stefanie

    2016-11-01

    Craniofacial growth changes in young children are not yet completely understood. Up-to-date references for craniofacial measurements are crucial for clinical assessment of orthodontic anomalies, craniofacial abnormalities and subsequent planning of interventions. To provide normal reference data and to identify growth patterns for craniofacial dimensions of European boys and girls aged 3-6 years. Using standard anthropometric methodology, body weight, body height and 23 craniofacial measurements were acquired for a cross-sectional sample of 681 healthy children (362 boys and 319 girls) aged 3-6 years from Germany, Italy and Lithuania. Descriptive statistics, correlation coefficients, percentage annual changes and percentage growth rates were used to analyse the dataset. Between the ages of 3-6 years, craniofacial measurements showed age- and sex-related patterns independent from patterns observed for body weight and body height. Sex-related differences were observed in the majority of craniofacial measurements. In both sexes, face heights and face depths showed the strongest correlation with age. Growth patterns differed by craniofacial measurement and can be summarised into eight distinct age- and sex-related patterns. This study provided reference data and identified sex- and age-related growth patterns of the craniofacial complex of young European children, which may be used for detailed assessment of normal growth in paediatrics, maxillofacial reconstructive surgery and possibly for forensic age assessment.

  11. Maternal Dietary Patterns and Fetal Growth: A Large Prospective Cohort Study in China

    PubMed Central

    Lu, Min-Shan; Chen, Qiao-Zhu; He, Jian-Rong; Wei, Xue-Ling; Lu, Jin-Hua; Li, Sheng-Hui; Wen, Xing-Xuan; Chan, Fan-Fan; Chen, Nian-Nian; Qiu, Lan; Mai, Wei-Bi; Zhang, Rui-Fang; Hu, Cui-Yue; Xia, Hui-Min; Qiu, Xiu

    2016-01-01

    There was limited evidence revealing the association of Chinese maternal dietary patterns with fetal growth. We aimed to examine the relationship of maternal dietary patterns during pregnancy to neonatal birth weight and birth weight for gestational age in a Chinese population. A total of 6954 mother-child pairs were included from the Born in Guangzhou Cohort Study. Maternal diet during pregnancy was assessed using a self-administered food frequency questionnaire. Cluster analysis was used to identify dietary patterns. The following six dietary patterns were identified: “Cereals, eggs, and Cantonese soups” (n 1026, 14.8%), “Dairy” (n 1020, 14.7%), “Fruits, nuts, and Cantonese desserts” (n 799, 11.5%), “Meats” (n 1066, 15.3%), “Vegetables” (n 1383, 19.9%), and “Varied” (n 1224, 17.6%). The mean neonatal birth weight Z scores of women in the above patterns were 0.02, 0.07, 0.20, 0.01, 0.06, and 0.14, respectively. Women in the “Fruits, nuts, and Cantonese desserts” and “Varied” groups had significantly heavier infants compared with those in the “Cereals, eggs, and Cantonese soups” group. Compared with women in the “Cereals, eggs, and Cantonese soups” group, those in the “Varied” group had marginally significantly lower odds of having a small-for-gestational age (SGA) infant after adjustment for other confounders (OR 0.77, 95% CI 0.57, 1.04, p = 0.08). These findings suggest that compared to a traditional Cantonese diet high in cereals, eggs, and Cantonese soups, a diet high in fruits, nuts, and Cantonese desserts might be associated with a higher birth weight, while a varied diet might be associated with a greater birth weight and also a decreased risk of having a SGA baby. PMID:27136584

  12. Effects of photoperiod on secretory patterns of growth hormone in adult male goats.

    PubMed

    Jin, Jin; Sawai, Ken; Hashizume, Tsutomu

    2013-12-01

    The aim of the present study was to clarify the effect of photoperiod on secretory patterns of growth hormone (GH) in male goats. Adult male goats were kept at 20°C with an 8-h or 16-h light photoperiod, and secretory patterns of GH secretion were compared. In addition, plasma profiles of prolactin (PRL), insulin-like growth factor-I (IGF-I) and testosterone (T) were also examined to characterize GH secretion. GH was secreted in a pulsatile manner. There was no significant difference in pulse frequency between the 8-h and 16-h photoperiods. However, GH pulse amplitude tended to be greater in the group with the 16-h photoperiod (P = 0.1), and mean GH concentrations were significantly greater in the 16-h photoperiod (P < 0.05). The GH-releasing response to GH releasing hormone was greater in the 16-h than 8-h photoperiod (P < 0.05). Plasma PRL and IGF-I levels were higher in the 16-h than 8-h photoperiod (P < 0.05). In contrast, plasma T levels were lower in the 16-h photoperiod (P < 0.05). These results show that a long light photoperiod enhances the secretion of GH as well as PRL and IGF-I, but reduces plasma T concentrations in male goats.

  13. Hydrocarbon distribution patterns in Nigerian growth-fault structures controlled by structural style and stratigraphy

    SciTech Connect

    Weber, K.J.

    1986-05-01

    Growth faults are considered to be major migration conduits in the Niger delta. However, the hydrocarbon distribution often shows such seemingly erratic patterns that doubt remains about the actual migration processes. After considering the sequential aspects of hydrocarbon generation and possible contemporaneous structural deformation, some of the apparent inconsistencies in the along-fault migration theory can be explained. When the authors study the relationship of fault-sealing capacity with the sand and shale thickness distribution, systematic patterns of hydrocarbon distribution are clearly revealed in many fields. The occurrence of several thick, somewhat undercompacted clay layers that locally form effective seals to vertical migration is also important. Structures with a predominance of thick sands and thin shales can trap large volumes of hydrocarbons, but only if they are unfaulted. More complex growth-fault structures, cut by secondary faults, will only be prominent oil fields if the shales are sufficiently thick to cause widespread fault sealing and shale-to-shale juxtaposition along faults. In many causes the lateral distribution of hydrocarbons over a series of fault blocks can be predicted fairly accurately on the basis of these considerations. An interesting phenomenon related to the proposed migration system is the occurrence of water trapped downdip from a hydrocarbon accumulation. Differences as large as 1000 ft can exist between the oil-water contacts on opposite flanks of a reservoir.

  14. Zebra pattern in rocks as a function of grain growth affected by second-phase particles

    NASA Astrophysics Data System (ADS)

    Kelka, Ulrich; Koehn, Daniel; Beaudoin, Nicolas

    2015-09-01

    In this communication we present a simple microdynamic model which can explain the beginning of the zebra pattern formation in rocks. The two dimensional model consists of two main processes, mineral replacement along a reaction front, and grain boundary migration affected by impurities. In the numerical model we assume that an initial distribution of second-phase particles is present due to sedimentary layering. The reaction front percolates the model and redistributes second-phase particles by shifting them until the front is saturated and drops the particles again. This produces and enhances initial layering. Grain growth is hindered in layers with high second-phase particle concentrations whereas layers with low concentrations coarsen. Due to the grain growth activity in layers with low second-phase particle concentrations these impurities are collected at grain boundaries and the crystals become very clean. Therefore the white layers in the pattern contain large grains with low concentration of second-phase particles, whereas the dark layers contain small grains with a large second-phase particle concentration.

  15. Constraints on growth and allocation patterns of Silphium integrifolium (Asteraceae) caused by a cynipid gall wasp.

    PubMed

    Fay, P A; Hartnett, D C

    1991-10-01

    Insect herbivory can have important effects on plant life histories and architecture. We quantified the impact that a cynipid gall wasp, Antistrophus silphii, had on growth, reproduction, and biomass allocation patterns of Silphium integrifolium growing in the tallgrass prairie of northeastern Kansas. Experimentally galled individual Silphium shoots (ramets) had reduced shoot growth, leaf and flower head production, and delayed flowering compared to gall-free control shoots. Gall formation completely halted normal apical growth in 65% of the shoots. Galling did not affect individual flower head weight, the numbers of achenes per flower head or achene weight. Silphium plants (genets) with a high proportion of galled shoots had lower total biomass, a lower proportion of total biomass allocated to flower heads, higher allocation to leaves, but no change in allocation to stems or rhizome. High gall densities reduced the number of flower heads per plant and shortened the time between flower head initiation and maturity. An adaptive interpretation of these results would be that the survivorship and future performance of galled Silphium may be promoted by maintaining allocation to rhizome. However, reduced shoot growth and delayed reproduction in galled Silphium may weaken its competitive ability and reduce pollination success, so that any adaptive advantage to Silphium's allocation responses to galls may be outweighed by disadvantages from its growth and flowering phenology responses. We conclude that a more parsimonious interpretation of these results is that gall-induced allocation changes are due to architectural constraints placed by galls on meristem activity, rather than to any adaptive response on the part of the plant.

  16. Patterns of Children's Adrenocortical Reactivity to Interparental Conflict and Associations with Child Adjustment: A Growth Mixture Modeling Approach

    ERIC Educational Resources Information Center

    Koss, Kalsea J.; George, Melissa R. W.; Davies, Patrick T.; Cicchetti, Dante; Cummings, E. Mark; Sturge-Apple, Melissa L.

    2013-01-01

    Examining children's physiological functioning is an important direction for understanding the links between interparental conflict and child adjustment. Utilizing growth mixture modeling, the present study examined children's cortisol reactivity patterns in response to a marital dispute. Analyses revealed three different patterns of cortisol…

  17. Patterns of Children's Adrenocortical Reactivity to Interparental Conflict and Associations with Child Adjustment: A Growth Mixture Modeling Approach

    ERIC Educational Resources Information Center

    Koss, Kalsea J.; George, Melissa R. W.; Davies, Patrick T.; Cicchetti, Dante; Cummings, E. Mark; Sturge-Apple, Melissa L.

    2013-01-01

    Examining children's physiological functioning is an important direction for understanding the links between interparental conflict and child adjustment. Utilizing growth mixture modeling, the present study examined children's cortisol reactivity patterns in response to a marital dispute. Analyses revealed three different patterns of cortisol…

  18. Forest stand structure and pattern of old-growth western hemlock/Douglas-fir and mixed-conifer forests

    Treesearch

    Malcolm North; Jiquan Chen; Brian Oakley; Bo Song; Mark Rudnicki; Andrew Gray; Jim Innes

    2004-01-01

    With fire suppression, many western forests are expected to have fewer gaps and higher stem density of shade-tolerant species as light competition becomes a more significant influence on stand pattern and composition. We compared species composition, structure, spatial pattern, and environmental factors such as light and soil moisture between two old-growth forests:...

  19. The 2000 Census and Growth Patterns in Rural America. The Main Street Economist: Commentary on the Rural Economy.

    ERIC Educational Resources Information Center

    Sheaff, Katharine

    The 2000 Census reveals four patterns of change in rural America. Rural areas in states such as Florida and Arizona are gaining population due to high retiree growth. These areas will experience growth in service sector jobs that have low pay and low educational requirements. Florida and Arizona trail the nation in high school and college…

  20. How Do Users Find Things with PubMed? Towards Automatic Utility Evaluation with User Simulations

    DTIC Science & Technology

    2008-02-01

    experimental variable was the algorithm for suggesting related articles. We considered two: • Using language modeling retrieval, implemented with Lemur [16...similarity algorithm in PubMed, accessed through the PubMed eUtils API.5 Quite explicitly, our goal was not to compare Lemur with PubMed, but rather to...for the simulation (utility). The top graph shows the greedy browsing strategy and the bottom graph the breadth-like browsing strategy, both with Lemur

  1. Early growth patterns are associated with intelligence quotient scores in children born small-for-gestational age.

    PubMed

    Varella, Marcia H; Moss, William J

    2015-08-01

    To assess whether patterns of growth trajectory during infancy are associated with intelligence quotient (IQ) scores at 4 years of age in children born small-for-gestational age (SGA). Children in the Collaborative Perinatal Project born SGA were eligible for analysis. The primary outcome was the Stanford-Binet IQ score at 4 years of age. Growth patterns were defined based on changes in weight-for-age z-scores from birth to 4 months and 4 to 12 months of age and consisted of steady, early catch-up, late catch-up, constant catch-up, early catch-down, late catch-down, constant catch-down, early catch-up & late catch-down, and early catch-down & late catch-up. Multivariate linear regression was used to assess associations between patterns of growth and IQ. We evaluated patterns of growth and IQ in 5640 children. Compared with children with steady growth, IQ scores were 2.9 [standard deviation (SD)=0.54], 1.5 (SD=0.63), and 2.2 (SD=0.9) higher in children with early catch-up, early catch-up and later catch-down, and constant catch-up growth patterns, respectively, and 4.4 (SD=1.4) and 3.9 (SD=1.5) lower in children with early catch-down & late catch-up, and early catch-down growth patterns, respectively. Patterns in weight gain before 4 months of age were associated with differences in IQ scores at 4 years of age, with children with early catch-up having slightly higher IQ scores than children with steady growth and children with early catch-down having slightly lower IQ scores. These findings have implications for early infant nutrition in children born SGA. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Diagnostic performance of various cephalometric parameters for the assessment of vertical growth pattern.

    PubMed

    Ahmed, Maheen; Shaikh, Attiya; Fida, Mubassar

    2016-01-01

    Multiple cephalometric analyses are used to diagnose vertical skeletal facial discrepancy. A multitude of times, these parameters show conflicting results, and a specific diagnosis is hard to reach. Hence, this study aimed to identify the skeletal analysis that performs best for the identification of vertical skeletal pattern in borderline cases. The sample consisted of 161 subjects (71 males and 90 females; mean age = 23.6 ± 4.6 years). Y-axis, Sella-Nasion to mandibular plane angle (SN.MP), maxillary plane to mandibular plane angle (MMA), Sella-Nasion to Gonion-Gnathion angle (SN.GoGn), Frankfort to mandibular plane angle (FMA), R-angle and facial height ratio (LAFH.TAFH) were used to evaluate vertical growth pattern on lateral cephalograms. The subjects were divided into three groups (hypodivergent, normodivergent and hyperdivergent groups), as indicated by the diagnostic results of the majority of parameters. Kappa statistics was applied to compare the diagnostic accuracy of various analyses. To further validate the results, sensitivity and positive predictive values (PPV) for each parameter were also calculated. SN.GoGn showed a substantial interclass agreement (k = 0.850). In the hypodivergent group, MMA showed the highest sensitivity (0.934), whereas FMA showed the highest PPV (0.964). In the normodivergent group, FMA showed the highest sensitivity (0.909) and SN.GoGn had the highest PPV (0.903). SN.GoGn showed the highest sensitivity (0.980) and PPV (0.87) in the hyperdivergent group. SN.GoGn and FMA were found to be the most reliable indicators, whereas LAFH.TAFH is the least reliable indicator in assessing facial vertical growth pattern. Hence, the cephalometric analyses may be limited to fewer analyses of higher diagnostic performance.

  3. Spatial patterns of tree-growth anomalies in the United States and southeastern Canada

    SciTech Connect

    Meko, D.; Stockton, C.W.; Hughes, M.K. ); Cook, E.R. ); Stahle, D.W. )

    1993-09-01

    A network of 248 tree-ring chronologies in the conterminous United States is assembled and analyzed by rotated principal components analysis (RPCA) to delineate [open quotes]regions[close quotes] of common tree-growth variation during the period 1705-1979. Spatial continuity of the tree-ring data is summarized by variogram analysis, and tree-ring data are gridded before RPCA to reduce effects of site clustering. Principal component drought information is evaluated by comparing PC scores and primary pattern coefficients with Palmer Drought Severity Index (PDSI) data from instrumental records. High PC pattern coefficients group geographically into regions coinciding roughly with nine drought regions delineated by RPCA of PDSI by other researchers. The drought signal as measured by the correlation between tree-ring PC scores and July PDSI, 1929-79, is strongest in the South and the interior West (r>0.7), and weakest in the Northeast and Pacific Northwest (r<0.16). A count of years with large negative PC scores in multiple regions marks the 1950s as the extreme in widespread drought across the southern United States to 1705. Tree-growth regions are sensitive to whether tree-ring data are gridded before RPCA. Principal components on ungridded tree-ring data to center on dense clusters of sites. The importance of site density is most noticeable in the RPCA results for the southeast, where the gridded data yield a PC centered on a group of climate-sensitive but widely spaced bald cypress chronologies. Cross-validation indicates that gridding of tree-ring anomalies over different species for drought reconstruction is more appropriate in the semiarid southwest than in cooler, moisture regions-especially the northeast and the Pacific Northwest. Our results endorse the large-scale chronology network as a long-term proxy for the spatial and temporal patterns of past drought across the United States. 41 refs., 12 figs., 2 tabs.

  4. Diagnostic performance of various cephalometric parameters for the assessment of vertical growth pattern

    PubMed Central

    Ahmed, Maheen; Shaikh, Attiya; Fida, Mubassar

    2016-01-01

    ABSTRACT Introduction: Multiple cephalometric analyses are used to diagnose vertical skeletal facial discrepancy. A multitude of times, these parameters show conflicting results, and a specific diagnosis is hard to reach. Objective: Hence, this study aimed to identify the skeletal analysis that performs best for the identification of vertical skeletal pattern in borderline cases. Methods: The sample consisted of 161 subjects (71 males and 90 females; mean age = 23.6 ± 4.6 years). Y-axis, Sella-Nasion to mandibular plane angle (SN.MP), maxillary plane to mandibular plane angle (MMA), Sella-Nasion to Gonion-Gnathion angle (SN.GoGn), Frankfort to mandibular plane angle (FMA), R-angle and facial height ratio (LAFH.TAFH) were used to evaluate vertical growth pattern on lateral cephalograms. The subjects were divided into three groups (hypodivergent, normodivergent and hyperdivergent groups), as indicated by the diagnostic results of the majority of parameters. Kappa statistics was applied to compare the diagnostic accuracy of various analyses. To further validate the results, sensitivity and positive predictive values (PPV) for each parameter were also calculated. Results: SN.GoGn showed a substantial interclass agreement (k = 0.850). In the hypodivergent group, MMA showed the highest sensitivity (0.934), whereas FMA showed the highest PPV (0.964). In the normodivergent group, FMA showed the highest sensitivity (0.909) and SN.GoGn had the highest PPV (0.903). SN.GoGn showed the highest sensitivity (0.980) and PPV (0.87) in the hyperdivergent group. Conclusions: SN.GoGn and FMA were found to be the most reliable indicators, whereas LAFH.TAFH is the least reliable indicator in assessing facial vertical growth pattern. Hence, the cephalometric analyses may be limited to fewer analyses of higher diagnostic performance. PMID:27653263

  5. Engineering the growth pattern and cell morphology for enhanced PHB production by Escherichia coli.

    PubMed

    Wu, Hong; Chen, Jinchun; Chen, Guo-Qiang

    2016-12-01

    E. coli JM109∆envC∆nlpD deleted with genes envC and nlpD responsible for degrading peptidoglycan (PG) led to long filamentous cell shapes. When cell fission ring location genes minC and minD of Escherichia coli were deleted, E. coli JM109∆minCD changed the cell growth pattern from binary division to multiple fissions. Bacterial morphology can be further engineered by overexpressing sulA gene resulting in inhibition on FtsZ, thus generating very long cellular filaments. By overexpressing sulA in E. coli JM109∆envC∆nlpD and E. coli JM109∆minCD harboring poly(3-hydroxybutyrate) (PHB) synthesis operon phbCAB encoded in plasmid pBHR68, respectively, both engineered cells became long filaments and accumulated more PHB compared with the wild-type. Under same shake flask growth conditions, E. coli JM109∆minCD (pBHR68) overexpressing sulA grown in multiple fission pattern accumulated approximately 70 % PHB in 9 g/L cell dry mass (CDM), which was significantly higher than E. coli JM109∆envC∆nlpD and the wild type, that produced 7.6 g/L and 8 g/L CDM containing 64 % and 51 % PHB, respectively. Results demonstrated that a combination of the new division pattern with elongated shape of E. coli improved PHB production. This provided a new vision on the enhanced production of inclusion bodies.

  6. Ovarian high-grade serous carcinoma with a noninvasive growth pattern simulating a serous borderline tumor.

    PubMed

    Imamura, Hiroko; Ohishi, Yoshihiro; Aman, Murasaki; Shida, Kaai; Shinozaki, Tomoko; Yasutake, Nobuko; Sonoda, Kenzo; Kato, Kiyoko; Oda, Yoshinao

    2015-10-01

    Ovarian serous borderline tumors (SBTs) being a precursor of low-grade serous carcinomas are morphologically characterized by noninvasive growth and low-grade cytology. On the other hand, many pathologists regard cytologically high-grade, noninvasive (HG-noninv) ovarian serous tumors resembling SBTs in low magnification as conventional high-grade serous carcinomas (HGSCs) by personal experiences. Nonetheless, there are no established molecular characteristic of such tumors. In this study, therefore, we attempted to provide the molecular evidence. We selected 37 ovarian serous tumors that exhibited a cytologically HG-noninv growth pattern, including 36 tumors that coexisted with conventional invasive HGSC components (HG-inv) and a single tumor exclusively composed of pure HG-noninv. Histologically, all HG-noninv showed many mitotic figures, and serous tubal intraepithelial carcinomas were identified in 3 tumors with HG-noninv. Immunohistochemically, most HG-noninv showed aberrant p53 expression, frequent IMP3 positivity, p16 overexpression, a high MIB-1 labeling index, and infrequent PAX2. By molecular analysis, the pure HG-noninv and 13 HGSCs with HG-noninv showed TP53 mutations, but KRAS/BRAF mutations were not detected in any of them. In 1 tumor, we detected an identical TP53 mutation in both HG-noninv and HG-inv components by using laser capture microdissection. These immunohistochemical and molecular features of HG-noninv were similar to those of conventional invasive HGSCs but different from those of SBTs. In conclusion, our results showed that a cytologically HG-noninv growth pattern simulating an SBT is a morphological spectrum of HGSC, but not a true SBT.

  7. The effect of butterfly-scale inspired patterning on leading-edge vortex growth

    NASA Astrophysics Data System (ADS)

    Wilroy, Jacob; Lang, Amy

    2015-11-01

    Leading edge vortices (LEVs) are important for generating thrust and lift in flapping flight, and the surface patterning (scales) on butterfly wings is hypothesized to play a role in the vortex formation of the LEV. To simplify this complex flow problem, an experiment was designed to focus on the alteration of 2-D vortex development with a variation in surface patterning. Specifically, the secondary vorticity generated by the LEV interacting at the patterned surface was studied and the subsequent affect on the growth rate of the circulation in the LEV. For this experiment we used butterfly inspired grooves attached to a flat plate and compared the vortex formation to a smooth plate case as the plate moved vertically. The plate is impulsively started in quiescent water and flow fields at Re = 1500, 3000, and 6000 are examined using Digital Particle Image Velocimetry (DPIV). The vortex formation time is 3.0 and is based on the flat plate travel length and chord length. We would like to thank the National Science Foundation REU Site Award 1358991 for funding this research.

  8. The Global Pattern of Urbanization and Economic Growth: Evidence from the Last Three Decades

    PubMed Central

    Chen, Mingxing; Zhang, Hua; Liu, Weidong; Zhang, Wenzhong

    2014-01-01

    The relationship between urbanization and economic growth has been perplexing. In this paper, we identify the pattern of global change and the correlation of urbanization and economic growth, using cross-sectional, panel estimation and geographic information systems (GIS) methods. The analysis has been carried out on a global geographical scale, while the timescale of the study spans the last 30 years. The data shows that urbanization levels have changed substantially during these three decades. Empirical findings from cross-sectional data and panel data support the general notion of close links between urbanization levels and GDP per capita. However, we also present significant evidence that there is no correlation between urbanization speed and economic growth rate at the global level. Hence, we conclude that a given country cannot obtain the expected economic benefits from accelerated urbanization, especially if it takes the form of government-led urbanization. In addition, only when all facets are taken into consideration can we fully assess the urbanization process. PMID:25099392

  9. The global pattern of urbanization and economic growth: evidence from the last three decades.

    PubMed

    Chen, Mingxing; Zhang, Hua; Liu, Weidong; Zhang, Wenzhong

    2014-01-01

    The relationship between urbanization and economic growth has been perplexing. In this paper, we identify the pattern of global change and the correlation of urbanization and economic growth, using cross-sectional, panel estimation and geographic information systems (GIS) methods. The analysis has been carried out on a global geographical scale, while the timescale of the study spans the last 30 years. The data shows that urbanization levels have changed substantially during these three decades. Empirical findings from cross-sectional data and panel data support the general notion of close links between urbanization levels and GDP per capita. However, we also present significant evidence that there is no correlation between urbanization speed and economic growth rate at the global level. Hence, we conclude that a given country cannot obtain the expected economic benefits from accelerated urbanization, especially if it takes the form of government-led urbanization. In addition, only when all facets are taken into consideration can we fully assess the urbanization process.

  10. Multidisciplinary characterization of the long-bone cortex growth patterns through sheep's ontogeny.

    PubMed

    Cambra-Moo, Oscar; Nacarino-Meneses, Carmen; Díaz-Güemes, Idoia; Enciso, Silvia; García Gil, Orosia; Llorente Rodríguez, Laura; Rodríguez Barbero, Miguel Ángel; de Aza, Antonio H; González Martín, Armando

    2015-07-01

    Bone researches have studied extant and extinct taxa extensively trying to disclose a complete view of the complex structural and chemical transformations that model and remodel the macro and microstructure of bone during growth. However, to approach bone growth variations is not an easy task, and many aspects related with histological transformations during ontogeny remain unresolved. In the present study, we conduct a holistic approach using different techniques (polarized microscopy, Raman spectroscopy and X-ray diffraction) to examine the histomorphological and histochemical variations in the cortical bone of sheep specimens from intrauterine to adult stages, using environmentally controlled specimens from the same species. Our results suggest that during sheep bone development, the most important morphological (shape and size) and chemical transformations in the cortical bone occur during the first weeks of life; synchronized but dissimilar variations are established in the forelimb and hind limb cortical bone; and the patterns of bone tissue maturation in both extremities are differentiated in the adult stage. All of these results indicate that standardized histological models are useful not only for evaluating many aspects of normal bone growth but also to understand other important influences on the bones, such as pathologies that remain unknown. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Directed Kinetic Self-Assembly of Mounds on Patterned GaAs (001): Tunable Arrangement, Pattern Amplification and Self-Limiting Growth

    PubMed Central

    Lin, Chuan-Fu; Kan, Hung-Chih; Kanakaraju, Subramaniam; Richardson, Christopher; Phaneuf, Raymond

    2014-01-01

    We present results demonstrating directed self-assembly of nanometer-scale mounds during molecular beam epitaxial growth on patterned GaAs (001) surfaces. The mound arrangement is tunable via the growth temperature, with an inverse spacing or spatial frequency which can exceed that of the features of the template. We find that the range of film thickness over which particular mound arrangements persist is finite, due to an evolution of the shape of the mounds which causes their growth to self-limit. A difference in the film thickness at which mounds at different sites self-limit provides a means by which different arrangements can be produced.

  12. Fetal and childhood growth patterns associated with bone mass in school-age children: the Generation R Study.

    PubMed

    Heppe, Denise Hm; Medina-Gomez, Carolina; de Jongste, Johan C; Raat, Hein; Steegers, Eric Ap; Hofman, Albert; Rivadeneira, Fernando; Jaddoe, Vincent Wv

    2014-12-01

    Low birth weight is associated with lower bone accrual in children and peak bone mass in adults. We assessed how different patterns of longitudinal fetal and early childhood growth influence bone properties at school age. In 5431 children participating in a population-based prospective cohort study, we measured fetal growth by ultrasound at 20 and 30 weeks gestation, and childhood growth at birth, 1, 2, 3, and 4 years of age. We analyzed these growth measurements in relation to total body (less head) BMD measured by DXA at age 6. We used conditional growth modeling; a technique which takes into account correlation between repeatedly measured growth measures. Our results showed that estimated fetal weight gain, femur length growth between 20 and 30 weeks of gestation, femur length growth between 30 weeks and birth, as well as all height and weight growth measurements from birth to 4 years of age were all positively associated with BMC, bone area (BA), and BMD (all p < 0.01). Fetal femur length growth between 30 weeks and birth was positively associated with BMC and BA (both p < 0.001), but not with BMD. Overall, childhood growth measurements exerted a larger influence on bone measures than fetal growth measures. The strongest effect estimate was observed during the first year of life. Children born small (<10th percentile) for gestational age (SGA) had lower BMC and BA, but not BMD, than children born appropriate for gestational age (AGA), whereas children born large (>90th percentile) for gestational age (LGA) had higher BMC and BA (all p < 0.001). These differences were no longer present in children showing subsequent accelerated and decelerated infant growth, respectively. We conclude that both fetal and childhood growth patterns are associated with bone mineral accrual, showing the strongest effect estimates in infancy. Compensatory infant growth counteracts the adverse consequences of fetal growth restriction on bone development. © 2014 American

  13. Mucin-1 correlates with survival, smoking status, and growth patterns in lung adenocarcinoma.

    PubMed

    Lappi-Blanco, Elisa; Mäkinen, Johanna M; Lehtonen, Siri; Karvonen, Henna; Sormunen, Raija; Laitakari, Kirsi; Johnson, Shirley; Mäkitaro, Riitta; Bloigu, Risto; Kaarteenaho, Riitta

    2016-10-01

    Mucin-1 (MUC1) affects cancer progression in lung adenocarcinoma, and its aberrant expression pattern has been correlated with poor tumor differentiation and impaired prognosis. In this study, the immunohistochemical expression of MUC1 and Mucin-4 (MUC4) was analyzed in a series of 106 surgically operated stage I-IV pulmonary adenocarcinomas. MUC1 immunohistochemistry was evaluated according to the Nagai classification, and the immunohistochemical profile of the tumors was correlated with detailed clinical and histological data. The effect of cigarette smoke on MUC1 expression in lung cancer cell lines was examined using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunoelectron microscopy (IEM). In contrast to the normal apical localization of MUC1, a basolateral and cytoplasmic (depolarized) MUC1 expression pattern was frequently encountered in the high-grade subtypes, i.e., solid predominant adenocarcinoma and the cribriform variant of acinar predominant adenocarcinoma (p < 0.001), and was rarely observed in tumors containing a non-predominant lepidic component (p < 0.001). Furthermore, the altered staining pattern of MUC1 correlated with stage (p = 0.002), reduced overall survival (p = 0.031), and was associated with smoking (p < 0.001). When H1650 adenocarcinoma cells were exposed to cigarette smoke and analyzed by RT-qPCR and IEM, the levels of the MUC1 transcript and protein were elevated (p = 0.042). In conclusion, MUC1 participates in the pathogenesis of lung adenocarcinoma and associates with smoking both in vitro and in vivo. In lung adenocarcinoma, depolarized MUC1 protein expression correlated with histological growth patterns, stage, and patient outcome.

  14. Elevational plant species richness patterns and their drivers across non-endemics, endemics and growth forms in the Eastern Himalaya.

    PubMed

    Manish, Kumar; Pandit, Maharaj K; Telwala, Yasmeen; Nautiyal, Dinesh C; Koh, Lian Pin; Tiwari, Sudha

    2017-09-01

    Despite decades of research, ecologists continue to debate how spatial patterns of species richness arise across elevational gradients on the Earth. The equivocal results of these studies could emanate from variations in study design, sampling effort and data analysis. In this study, we demonstrate that the richness patterns of 2,781 (2,197 non-endemic and 584 endemic) angiosperm species along an elevational gradient of 300-5,300 m in the Eastern Himalaya are hump-shaped, spatial scale of extent (the proportion of elevational gradient studied) dependent and growth form specific. Endemics peaked at higher elevations than non-endemics across all growth forms (trees, shrubs, climbers, and herbs). Richness patterns were influenced by the proportional representation of the largest physiognomic group (herbs). We show that with increasing spatial scale of extent, the richness patterns change from a monotonic to a hump-shaped pattern and richness maxima shift toward higher elevations across all growth forms. Our investigations revealed that the combination of ambient energy (air temperature, solar radiation, and potential evapo-transpiration) and water availability (soil water content and precipitation) were the main drivers of elevational plant species richness patterns in the Himalaya. This study highlights the importance of factoring in endemism, growth forms, and spatial scale when investigating elevational gradients of plant species distributions and advances our understanding of how macroecological patterns arise.

  15. A comparative study of embryonic development of some bird species with different patterns of postnatal growth.

    PubMed

    Blom, Jonas; Lilja, Clas

    2005-01-01

    Some studies show that birds with high postnatal growth rates (e.g. altricial species) are characterized by a rapid early development of "supply" organs, such as digestive organs. Birds with low postnatal growth rates (e.g. precocial species) exhibit a slower early development of these organs and a more rapid early development of other "demand" organs, such as brain, muscles, skeleton and feathers. To test whether these differences can be traced back to early embryonic development and whether they can be associated with changes in developmental timing, i.e. heterochrony, we compared embryos of the precocial quail and the altricial fieldfare, two bird species with low and high postnatal growth rates, respectively. We used classical staging techniques that use developmental landmarks to categorize embryonic maturity as well as morphological measurements. These techniques were combined with immune detection of muscle specific proteins in the somites. Our data showed that the anlagen of the head, brain and eyes develop earlier in the quail than in the fieldfare in contrast to the gut which develops earlier in the fieldfare than in the quail. Our data also showed that the quail and the fieldfare displayed different rates of myotome formation in the somites which contribute to muscle formation in the limbs and thorax. We believe these observations are connected with important differences in neonatal characteristics, such as the size of the brain, eyes, organs for locomotion and digestion. This leads us to the conclusion that selection for late ontogenetic characteristics can alter early embryonic development and that growth rate is of fundamental importance for the patterning of avian embryonic development. It also appears that this comparative system offers excellent opportunities to test hypotheses about heterochrony.

  16. Cross-cultural patterns of growth and nutritional status of breast-fed infants.

    PubMed

    Dewey, K G

    1998-01-01

    Growth patterns and iron status of infants who were breast-fed throughout their first year of life were examined in four populations: 1) a group of high socioeconomic status in California (the DARLING Study), 2) infants of normal birth weight (NBW) but from low-income families in Honduras, 3) low-birth-weight (LBW), full-term infants in Honduras, and 4) infants in Ghana. z Scores were calculated by using both the current National Center for Health Statistics reference data and a pooled data set based on breast-fed infants in six industrialized countries. The NBW infants in Honduras showed rapid growth in the first few months and were similar in weight-for-age to the DARLING infants until approximately 9 mo. By contrast, the LBW infants remained far below the other cohorts throughout the first 12 mo, despite an initial period of catch-up growth. In the Ghanaian infants, weight-for-age faltered beginning at 3-4 mo, but length-for-age did not falter until after 9 mo. Weight-for-length was highest in the NBW Honduran infants and lowest in the Ghanaian infants. When z scores were adjusted for birth weight and maternal height, no significant faltering was evident in either weight or length in any of the cohorts during the first 12 mo. Thus, when breast-feeding is continued during the first year of life and efforts are made to ensure adequate complementary feeding after 6 mo, if growth faltering occurs it is probably attributable to prenatal factors and maternal stature. Population differences in iron status reflected variation in birth weight and in the use of iron-rich foods. Therefore, efforts to prevent child stunting and malnutrition must pay attention to prenatal as well as postnatal factors.

  17. Looking for age-related growth decline in natural forests: unexpected biomass patterns from tree rings and simulated mortality

    USGS Publications Warehouse

    Foster, Jane R.; D'Amato, Anthony W.; Bradford, John B.

    2014-01-01

    Forest biomass growth is almost universally assumed to peak early in stand development, near canopy closure, after which it will plateau or decline. The chronosequence and plot remeasurement approaches used to establish the decline pattern suffer from limitations and coarse temporal detail. We combined annual tree ring measurements and mortality models to address two questions: first, how do assumptions about tree growth and mortality influence reconstructions of biomass growth? Second, under what circumstances does biomass production follow the model that peaks early, then declines? We integrated three stochastic mortality models with a census tree-ring data set from eight temperate forest types to reconstruct stand-level biomass increments (in Minnesota, USA). We compared growth patterns among mortality models, forest types and stands. Timing of peak biomass growth varied significantly among mortality models, peaking 20–30 years earlier when mortality was random with respect to tree growth and size, than when mortality favored slow-growing individuals. Random or u-shaped mortality (highest in small or large trees) produced peak growth 25–30 % higher than the surviving tree sample alone. Growth trends for even-aged, monospecific Pinus banksiana or Acer saccharum forests were similar to the early peak and decline expectation. However, we observed continually increasing biomass growth in older, low-productivity forests of Quercus rubra, Fraxinus nigra, and Thuja occidentalis. Tree-ring reconstructions estimated annual changes in live biomass growth and identified more diverse development patterns than previous methods. These detailed, long-term patterns of biomass development are crucial for detecting recent growth responses to global change and modeling future forest dynamics.

  18. Looking for age-related growth decline in natural forests: unexpected biomass patterns from tree rings and simulated mortality.

    PubMed

    Foster, Jane R; D'Amato, Anthony W; Bradford, John B

    2014-05-01

    Forest biomass growth is almost universally assumed to peak early in stand development, near canopy closure, after which it will plateau or decline. The chronosequence and plot remeasurement approaches used to establish the decline pattern suffer from limitations and coarse temporal detail. We combined annual tree ring measurements and mortality models to address two questions: first, how do assumptions about tree growth and mortality influence reconstructions of biomass growth? Second, under what circumstances does biomass production follow the model that peaks early, then declines? We integrated three stochastic mortality models with a census tree-ring data set from eight temperate forest types to reconstruct stand-level biomass increments (in Minnesota, USA). We compared growth patterns among mortality models, forest types and stands. Timing of peak biomass growth varied significantly among mortality models, peaking 20-30 years earlier when mortality was random with respect to tree growth and size, than when mortality favored slow-growing individuals. Random or u-shaped mortality (highest in small or large trees) produced peak growth 25-30% higher than the surviving tree sample alone. Growth trends for even-aged, monospecific Pinus banksiana or Acer saccharum forests were similar to the early peak and decline expectation. However, we observed continually increasing biomass growth in older, low-productivity forests of Quercus rubra, Fraxinus nigra, and Thuja occidentalis. Tree-ring reconstructions estimated annual changes in live biomass growth and identified more diverse development patterns than previous methods. These detailed, long-term patterns of biomass development are crucial for detecting recent growth responses to global change and modeling future forest dynamics.

  19. Healing time for the growth of thin films on patterned substrates

    NASA Astrophysics Data System (ADS)

    Chanphana, R.; Chatraphorn, P.; Dasgupta, C.

    2014-08-01

    The healing times for the growth of thin films on patterned substrates are studied using simulations of two discrete models of surface growth: the Family model and the Das Sarma-Tamborenea (DT) model. The healing time, defined as the time at which the characteristics of the growing interface are “healed” to those obtained in growth on a flat substrate, is determined via the study of the nearest-neighbor height difference correlation function. Two different initial patterns are considered in this work: a relatively smooth tent-shaped triangular substrate and an atomically rough substrate with single-site pillars or grooves. We find that the healing time of the Family and DT models on a L×L triangular substrate is proportional to Lz, where z is the dynamical exponent of the models. For the Family model, we also analyze theoretically, using a continuum description based on the linear Edwards-Wilkinson equation, the time evolution of the nearest-neighbor height difference correlation function in this system. The correlation functions obtained from continuum theory and simulation are found to be consistent with each other for the relatively smooth triangular substrate. For substrates with periodic and random distributions of pillars or grooves of varying size, the healing time is found to increase linearly with the height (depth) of pillars (grooves). We show explicitly that the simulation data for the Family model grown on a substrate with pillars or grooves do not agree with results of a calculation based on the continuum Edwards-Wilkinson equation. This result implies that a continuum description does not work when the initial pattern is atomically rough. The observed dependence of the healing time on the substrate size and the initial height (depth) of pillars (grooves) can be understood from the details of the diffusion rule of the atomistic model. The healing time of both models for pillars is larger than that for grooves with depth equal to the height of the

  20. Patterns of Children’s Adrenocortical Reactivity to Interparental Conflict and Associations with Child Adjustment: A Growth Mixture Modeling Approach

    PubMed Central

    Koss, Kalsea J.; George, Melissa R. W.; Davies, Patrick T.; Cicchetti, Dante; Cummings, E. Mark; Sturge-Apple, Melissa L.

    2013-01-01

    Examining children’s physiological functioning is an important direction for understanding the links between interparental conflict and child adjustment. Utilizing growth mixture modeling, the present study examined children’s cortisol reactivity patterns in response to a marital dispute. Analyses revealed three different patterns of cortisol responses, consistent with both a sensitization and an attenuation hypothesis. Child-rearing disagreements and perceived threat were associated with children exhibiting a rising cortisol pattern whereas destructive conflict was related to children displaying a flat pattern. Physiologically rising patterns were also linked with emotional insecurity and internalizing and externalizing behaviors. Results supported a sensitization pattern of responses as maladaptive for children in response to marital conflict with evidence also linking an attenuation pattern with risk. The present study supports children’s adrenocortical functioning as one mechanism through which interparental conflict is related to children’s coping responses and psychological adjustment. PMID:22545835

  1. Cell length growth patterns in fission yeast reveal a novel size control mechanism operating in late G2 phase.

    PubMed

    Horváth, Anna; Rácz-Mónus, Anna; Buchwald, Peter; Sveiczer, Ákos

    2016-09-01

    Because cylindrically shaped fission yeast cells grow exclusively at their tips, cell volume is proportional to length and can be easily monitored by time-lapse microscopy. Here, we analysed the growth pattern of individual cells from several fission yeast strains to determine the growth function that describes them most adequately and to perform size control studies. The growth pattern of most cells during their growth period is best described by a bilinear function (i.e., two linear segments of different growth rates separated by a rate-change point). Linear growth patterns were also observed in several cases, but exponential ones only rarely. Since the bilinear patterns are separated into two segments by a breakpoint, we examined the existence of size control by regression analyses of the appropriate growth parameters in both segments. This confirmed the existence of known size controls in late G1, mid-G2 and late G2 during the fission yeast cycle. The present analyses also revealed that, contrary to the commonly accepted current view, late G2 size control is a general characteristic third event in the cycle. The level of the critical late G2 size that needs to be reached in an individual fission yeast cell is influenced by the growth rate of the cell in a manner similar to budding yeast, suggesting an evolutionary conserved mechanism. The present study of individual cell growth patterns in wild-type and several cell cycle mutant fission yeast strains confirmed that, for most cells, growth is best described by a bilinear function. Three different size control mechanisms were found to operate in the different strains, and, as a novel observation, cell size was always found to be monitored before mitotic onset, irrespective of the existence of any earlier size checkpoints. Studying the pattern of growth and the mechanism of size control helps to clarify the connections between cell growth and division, since their coordination must work properly to maintain size

  2. RNA interference silencing of CHS greatly alters the growth pattern of apple (Malus x domestica).

    PubMed

    Dare, Andrew P; Hellens, Roger P

    2013-08-01

    Plants produce a vast array of phenolic compounds which are essential for their survival on land. One major class of polyphenols are the flavonoids and their formation is dependent on the enzyme chalcone synthase (CHS). In a recent study we silenced the CHS genes of apple (Malus × domestica Borkh.) and observed a loss of pigmentation in the fruit skin, flowers and stems. More surprisingly, highly silenced lines were significantly reduced in size, with small leaves and shortened internode lengths. Chemical analysis also revealed that the transgenic shoots contained greatly reduced concentrations of flavonoids which are known to modulate auxin flow. An auxin transport study verified this, with an increased auxin transport in the CHS-silenced lines. Overall, these findings suggest that auxin transport in apple has adapted to take place in the presence of high endogenous concentrations of flavonoids. Removal of these compounds therefore results in abnormal auxin movement and a highly disrupted growth pattern.

  3. Differentiation of bacterial colonies and temporal growth patterns using hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Mehrübeoglu, Mehrube; Buck, Gregory W.; Livingston, Daniel W.

    2014-09-01

    Detection and identification of bacteria are important for health and safety. Hyperspectral imaging offers the potential to capture unique spectral patterns and spatial information from bacteria which can then be used to detect and differentiate bacterial species. Here, hyperspectral imaging has been used to characterize different bacterial colonies and investigate their growth over time. Six bacterial species (Pseudomonas fluorescens, Escherichia coli, Serratia marcescens, Salmonella enterica, Staphylococcus aureus, Enterobacter aerogenes) were grown on tryptic soy agar plates. Hyperspectral data were acquired immediately after, 24 hours after, and 96 hours after incubation. Spectral signatures from bacterial colonies demonstrated repeatable measurements for five out of six species. Spatial variations as well as changes in spectral signatures were observed across temporal measurements within and among species at multiple wavelengths due to strengthening or weakening reflectance signals from growing bacterial colonies based on their pigmentation. Between-class differences and within-class similarities were the most prominent in hyperspectral data collected 96 hours after incubation.

  4. Interactions in the patterns of vegetative growth and reproduction in woody dioecious plants.

    PubMed

    Hoffmann, A J; Alliende, M C

    1984-01-01

    Interactions between vegetative growth and reproduction were evaluated in Peumus boldus, Lithraea caustica and Laretia acaulis, three woody dioecious species in central Chile. Phenological observations were made periodically on marked branches of male and female plants, and biomass allocation (dry weight) to vegetative and reproductive tissues was measured. The magnitude of flowering was evaluated in groups of plants in three successive seasons. The patterns of activities are species- and sex-dependent, and cycles of 2-4 years have been established. Branches that produce flowers either do not grow or grow less than branches without flowers, and males and females have differential resource allocation: male branches attain higher biomass values. Groups of plants show seasonal behavior that suggest synchrony in their reproductive activities.

  5. Crystal growth induced by Nd:YAG laser irradiation in patterning glass ceramic substrates with dots

    NASA Astrophysics Data System (ADS)

    Sola, D.; Escartín, A.; Cases, R.; Peña, J. I.

    2011-03-01

    In this work a glass ceramic substrate was processed by focusing a laser beam inside the said material. The crystal phase within the amorphous matrix provides mechanical properties to the glass ceramic substrate in such a way that dots can be patterned inside the fore-mentioned material without producing any cracks. These marks are made up of crystals, the growth of which has been induced by the laser beam. These inner structures can modify the optical, thermal and mechanical properties of the glass ceramic substrate. A Q-switched Nd:YAG laser at its fundamental wavelength of 1064 nm with pulsewidths in the nanosecond range has been used. Morphology, composition, microstructure, mechanical and thermal properties of the processed material are described.

  6. Pattern selection in a boundary-layer model of dendritic growth in the presence of impurities

    NASA Technical Reports Server (NTRS)

    Karma, A.; Kotliar, B. G.

    1985-01-01

    Presently analyzed, in the context of a boundary-layer model, is the problem of pattern selection in dendritic growth in a situation where impurities are present in the undercooled liquid. It is found that the tip-velocity selection criterion that has been proposed recently for the geometrical model and the boundary-layer model of a pure substance can be extended, in a nontrivial way, to this more complex situation where two coupled diffusion fields (temperature and solute) determine the interface dynamics. This model predicts a sharp enhancement of tip velocity in good qualitative agreement with experiment. This agreement is consistent with the conjecture that a solvability condition can be used to determine the operating point of the dendrite in the full nonlocal problem.

  7. Universal patterns of equilibrium cluster growth in aqueous sugars observed by dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Sidebottom, D. L.; Tran, Tri D.

    2010-11-01

    Dynamic light scattering performed on aqueous solutions of three sugars (glucose, maltose and sucrose) reveal a common pattern of sugar cluster formation with a narrow cluster size distribution. In each case, equilibrium clusters form whose size increases with increasing sugar content in an identical power law manner in advance of a common, critical-like, percolation threshold near 83wt% sugar. The critical exponent of the power law divergence of the cluster size varies with temperature, increasing with decreasing temperature, due to changes in the strength of the intermolecular hydrogen bond and appears to vanish for temperatures in excess of 90°C . Detailed analysis of the cluster growth process suggests a two-stage process: an initial cluster phase formed at low volume fractions, ϕ , consisting of noninteracting, monodisperse sugar clusters whose size increases ϕ1/3 followed by an aggregation stage, active at concentrations above about ϕ=40% , where cluster-cluster contact first occurs.

  8. Three PubMed skills to support evidence-based dentistry.

    PubMed

    Deahl, S Thomas

    2011-02-01

    The National Library of Medicine's PubMed database can powerfully assist dentists in evidence-based practice. Three useful PubMed skills can improve the efficiency of the clinician's search: (1) Use of MeSH terms; (2) Use of Limits; (3) Use of Clinical Queries.

  9. A new perspective on the growth pattern of the Wandering Albatross (Diomedea exulans) through DEB theory

    NASA Astrophysics Data System (ADS)

    Teixeira, Carlos M. G. L.; Sousa, Tânia; Marques, Gonçalo M.; Domingos, Tiago; Kooijman, Sebastiaan A. L. M.

    2014-11-01

    The Wandering Albatross (Diomedea exulans) and other seabirds exhibit a growing pattern that includes a period of body mass decrease before fledging. Several hypotheses have been suggested to explain it without success. We hypothesized that: 1) chicks and adults have similar metabolic traits regulating assimilation, growth and maturation; 2) there is a difference in locomotion effort between chicks and adults, and 3) chicks are exposed to a decline in food availability before fledging. This set of hypotheses allows for an energy surplus to be available and stored in reserve during the first months of development, explaining the mass recession that starts before fledging and the fact that adults keep a lower weight than fledglings, throughout the rest of their life span. To test this set of hypotheses we applied the Dynamic Energy Budget (DEB) theory. Using a small set of life-history traits and growth curves we parameterized the DEB standard model. We confirmed this set of hypotheses and estimated the pattern of decline in food availability that explains mass recession. An assessment of the daily energy intake was also performed. The implications related to that energy flux and diet composition are discussed based on current knowledge. The DEB model for the Wandering Albatross also provided estimates for the adult daily food ingested by adults (464.06 kJ kg- 1 d- 1), fasting capacity (25 d), Field Metabolic Rate (4.29 W kg- 1) and resting metabolic rate (2.87 W kg- 1). These values are consistent with the averages obtained in the field, suggesting that DEB may be useful to provide good estimations on a broader scale.

  10. Patterns of deregulation of insulin growth factor signalling pathway in paediatric and adult gastrointestinal stromal tumours.

    PubMed

    Italiano, Antoine; Chen, Junwei; Zhang, Lei; Hajdu, Mihai; Singer, Samuel; DeMatteo, Ronald P; Antonescu, Cristina R

    2012-11-01

    Data regarding the patterns and the mechanisms of deregulation of the insulin growth factor (IGF) pathway in adult and paediatric gastrointestinal stromal tumours (GISTs) are limited. We investigated the expression profiling of the genes encoding the main components of the IGF signalling pathway in 131 GISTs (106 adults, 21 paediatric and four young adults) and 25 other soft-tissue sarcomas (STS) using an Affymetrix U133A platform. IGF2 was investigated for loss of imprinting (LOI) whereas IGF1R was analysed for copy number aberration and mutation. IGF2 was the most highly overexpressed gene of the IGF pathway in GIST. IGF2 expression was also significantly higher than in other STS. IGF2 expression was correlated to the age onset and mutational status of GIST. Indeed, IGF2 expression was significantly higher in the 'adult' group than in the 'paediatric' and 'young adult' groups. Among adult GIST, IGF2 expression was higher in tumours lacking Homo sapiens v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) or alpha-type platelet-derived growth factor receptor (PDGFRA) mutations in comparison with mutated cases. A trend for a higher expression of IGF2 in resistant GIST in comparison to responsive GIST was also found. Overexpression of IGF2 was not related to LOI. Conversely, the expression of the IGF1R gene was significantly higher in the paediatric group than in the adult group. No copy number gains or mutations of IGF1R were observed. The IGF pathway is deregulated in GIST with distinct patterns according to age onset and mutational status. The IGF pathway may represent a therapeutic target in patients with primary or secondary resistance to imatinib. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Do symplasmic networks in cambial zones correspond with secondary growth patterns?

    PubMed

    Fuchs, Maike; van Bel, Aart Jan Eeuwe; Ehlers, Katrin

    2011-01-01

    The plasmodesmal (PD) network in the cambial zone of Arabidopsis thaliana hypocotyls was analysed using electron microscopy and dye-coupling studies and compared to those of internodes of Populus nigra and Solanum lycopersicum. In all species, PD densities and frequencies undergo alterations in topologically successive cambial walls reflecting species-specific patterns of PD degradation and PD insertion during cell development. Longitudinal PD fission is responsible for an abrupt increment of PD numbers in specific walls of the youngest derivatives at the xylem and/or phloem side. Here, PDs seem to mediate positional signalling to control tissue fate and early cell determination. PD numbers at all cambial interfaces of A. thaliana correspond to those of the herbaceous tomato, but are higher with the woody poplar. This suggests a positive correlation between PD frequencies and the rapidity of cell division activity. Photoactivated green fluorescent protein (26 kDa) did not diffuse through cambial PDs of A. thaliana. This is in keeping with the common size exclusion limit (SEL) of 8-10 kDa observed for PDs at the youngest interfaces of tomato and poplar which may mediate diffusive exchange of developmental signals of equal molecular size. The regular growth patterns in internodal cambial zones of poplar and tomato result from synchronized cell division activity of neighbouring initials. A. thaliana hypocotyls have an irregular mode of secondary growth. Here, signalling through PDs in misaligned radial walls between non-homologous derivatives may control tissue development. The observed organizational differences between the cambia cast doubts on the suitability of A. thaliana as a model plant for cambial research.

  12. Expression Patterns of CREBs in Oocyte Growth and Maturation of Fish

    PubMed Central

    Wang, De-Shou; Sudhakumari, Cheni-Chery; Kobayashi, Tohru; Nagahama, Yoshitaka

    2015-01-01

    In fish, oocyte meiotic maturation is regulated by 17α, 20β-dihydroxy-progesterone through cAMP. To study the role of cAMP response element binding protein (CREB) in meiotic maturation, we cloned and characterized the expression pattern of CREBs from two fish models, the Nile tilapia and catfish. In the Nile tilapia three different CREBs were identified where in CREB1 was found in many tissues including gonads with abundant expression in testis. CREB2, few amino acids shorter than CREB1, was expressed in several tissues with abundant expression in ovary. In addition, a 3’UTR variant form, CREB3 was exclusively found in ovary. During natural 14-day ovarian cycle of the Nile tilapia, CREB1 expression was stable throughout vitellogenesis with a sharp decrease on the day of spawning. In contrast, CREB2 remain unchanged throughout the ovarian cycle, however elevated in 11-day full-grown immature ovarian follicle and after hCG-induction. Interestingly, CREB3 expression was induced three folds on the day of spawning as well as during hCG-induced oocyte maturation. Based on the synergistic expression pattern, CREB1 is likely to control oocyte growth, whereas CREB 2 and 3 contribute to oocyte maturation in tilapia and the latter seems to be critical. In catfish, a single form of CREB showed a maximum expression during spawning phase and hCG-induced maturation both in vivo and in vitro augmented CREB expression. These results suggest that spatial and temporal expression of CREBs seems to be important for final oocyte maturation and may also regulate oocyte growth in fish. PMID:26700177

  13. Using PubMed in radiology: Ten useful tips for radiologists

    PubMed Central

    Sriganesh, Vasumathi

    2011-01-01

    PubMed contains a bibliography of articles published in around 4800 journals. It combines MEDLINE and OLDMEDLINE (articles from 1960, going back till the 1940s). PubMed is updated on a daily basis; to include both published and ahead of print references. As a radiologist, one can use PubMed to track several journals, track topics, search for specific topics, verify incomplete or incorrect references, store one's own publications, and save selected references; one can also create filters depending on one's own search needs for some regular topics. This article provides some key background knowledge on searching PubMed and also describes some features that are often left unexplored. The PubMed site has undergone many changes in the last few years and this article will update users on the current features. PMID:22013289

  14. Using PubMed in radiology: Ten useful tips for radiologists.

    PubMed

    Sriganesh, Vasumathi

    2011-07-01

    PubMed contains a bibliography of articles published in around 4800 journals. It combines MEDLINE and OLDMEDLINE (articles from 1960, going back till the 1940s). PubMed is updated on a daily basis; to include both published and ahead of print references. As a radiologist, one can use PubMed to track several journals, track topics, search for specific topics, verify incomplete or incorrect references, store one's own publications, and save selected references; one can also create filters depending on one's own search needs for some regular topics. This article provides some key background knowledge on searching PubMed and also describes some features that are often left unexplored. The PubMed site has undergone many changes in the last few years and this article will update users on the current features.

  15. Simulating Spatial Growth Patterns in Developing Countries: A Case of Shama in the Western Region of Ghana.

    NASA Astrophysics Data System (ADS)

    Inkoom, J. N.; Nyarko, B. K.

    2014-12-01

    The integration of geographic information systems (GIS) and agent-based modelling (ABM) can be an efficient tool to improve spatial planning practices. This paper utilizes GIS and ABM approaches to simulate spatial growth patterns of settlement structures in Shama. A preliminary household survey on residential location decision-making choice served as the behavioural rule for household agents in the model. Physical environment properties of the model were extracted from a 2005 image implemented in NetLogo. The resulting growth pattern model was compared with empirical growth patterns to ascertain the model's accuracy. The paper establishes that the development of unplanned structures and its evolving structural pattern are a function of land price, proximity to economic centres, household economic status and location decision-making patterns. The application of the proposed model underlines its potential for integration into urban planning policies and practices, and for understanding residential decision-making processes in emerging cities in developing countries. Key Words: GIS; Agent-based modelling; Growth patterns; NetLogo; Location decision making; Computational Intelligence.

  16. Patterns in longitudinal growth of refraction in Southern Chinese children: cluster and principal component analysis.

    PubMed

    Chen, Yanxian; Chang, Billy Heung Wing; Ding, Xiaohu; He, Mingguang

    2016-11-22

    In the present study we attempt to use hypothesis-independent analysis in investigating the patterns in refraction growth in Chinese children, and to explore the possible risk factors affecting the different components of progression, as defined by Principal Component Analysis (PCA). A total of 637 first-born twins in Guangzhou Twin Eye Study with 6-year annual visits (baseline age 7-15 years) were available in the analysis. Cluster 1 to 3 were classified after a partitioning clustering, representing stable, slow and fast progressing groups of refraction respectively. Baseline age and refraction, paternal refraction, maternal refraction and proportion of two myopic parents showed significant differences across the three groups. Three major components of progression were extracted using PCA: "Average refraction", "Acceleration" and the combination of "Myopia stabilization" and "Late onset of refraction progress". In regression models, younger children with more severe myopia were associated with larger "Acceleration". The risk factors of "Acceleration" included change of height and weight, near work, and parental myopia, while female gender, change of height and weight were associated with "Stabilization", and increased outdoor time was related to "Late onset of refraction progress". We therefore concluded that genetic and environmental risk factors have different impacts on patterns of refraction progression.

  17. Hydraulic redistribution of soil water in two old-growth coniferous forests: quantifying patterns and controls.

    PubMed

    Warren, Jeffrey M; Meinzer, Frederick C; Brooks, J Renée; Domec, Jean-Christophe; Coulombe, Rob

    2007-01-01

    Although hydraulic redistribution of soil water (HR) by roots is a widespread phenomenon, the processes governing spatial and temporal patterns of HR are not well understood. We incorporated soil/plant biophysical properties into a simple model based on Darcy's law to predict seasonal trajectories of HR. We investigated the spatial and temporal variability of HR across multiple years in two old-growth coniferous forest ecosystems with contrasting species and moisture regimes by measurement of soil water content (theta) and water potential (Psi) throughout the upper soil profile, root distribution and conductivity, and relevant climate variables. Large HR variability within sites (0-0.5 mm d(-1)) was attributed to spatial patterns of roots, soil moisture and depletion. HR accounted for 3-9% of estimated total site water depletion seasonally, peaking at 0.16 mm d(-1) (ponderosa pine; Pinus ponderosa) or 0.30 mm d(-1) (Douglas-fir; Pseudotsuga menziesii), then declining as modeled pathway conductance dropped with increasing root cavitation. While HR can vary tremendously within a site, among years and among ecosystems, this variability can be explained by natural variability in Psi gradients and seasonal courses of root conductivity.

  18. Large-scale pattern growth of graphene films for stretchable transparent electrodes.

    PubMed

    Kim, Keun Soo; Zhao, Yue; Jang, Houk; Lee, Sang Yoon; Kim, Jong Min; Kim, Kwang S; Ahn, Jong-Hyun; Kim, Philip; Choi, Jae-Young; Hong, Byung Hee

    2009-02-05

    Problems associated with large-scale pattern growth of graphene constitute one of the main obstacles to using this material in device applications. Recently, macroscopic-scale graphene films were prepared by two-dimensional assembly of graphene sheets chemically derived from graphite crystals and graphene oxides. However, the sheet resistance of these films was found to be much larger than theoretically expected values. Here we report the direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers, and present two different methods of patterning the films and transferring them to arbitrary substrates. The transferred graphene films show very low sheet resistance of approximately 280 Omega per square, with approximately 80 per cent optical transparency. At low temperatures, the monolayers transferred to silicon dioxide substrates show electron mobility greater than 3,700 cm(2) V(-1) s(-1) and exhibit the half-integer quantum Hall effect, implying that the quality of graphene grown by chemical vapour deposition is as high as mechanically cleaved graphene. Employing the outstanding mechanical properties of graphene, we also demonstrate the macroscopic use of these highly conducting and transparent electrodes in flexible, stretchable, foldable electronics.

  19. Wnt5a regulates growth, patterning, and odontoblast differentiation of developing mouse tooth

    PubMed Central

    Lin, Minkui; Li, Lu; Liu, Chao; Liu, Hongbing; He, Fenglei; Yan, Fuhua; Zhang, Yanding; Chen, YiPing

    2011-01-01

    Wnt/β-catenin signaling is essential for tooth development beyond the bud stage, but little is known about the role of non-canonical Wnt signaling in odontogenesis. Here we compared the expression of Wnt5a, a representative of noncanonical Wnts, with that of Ror2, the Wnt5a receptor for non-canonical signaling, in the developing tooth, and analyzed tooth phenotype in Wnt5a mutants. Wnt5a deficient mice exhibit retarded tooth development beginning from E16.5, leading to the formation of smaller and abnormally patterned teeth with a delayed odontoblast differentiation at birth. These defects are associated with upregulated Axin2 and Shh expression in the dental epithelium and reduced levels of cell proliferation in the dental epithelium and mesenchyme. Retarded tooth development and defective odontoblast differentiation were also observed in Ror2 mutant mice. Our results suggest that Wnt5a regulates growth, patterning, and odontoblast differentiation during odontogenesis, at least partially by modulating Wnt/β-catenin canonical signaling. PMID:21246660

  20. Patterns in longitudinal growth of refraction in Southern Chinese children: cluster and principal component analysis

    PubMed Central

    Chen, Yanxian; Chang, Billy Heung Wing; Ding, Xiaohu; He, Mingguang

    2016-01-01

    In the present study we attempt to use hypothesis-independent analysis in investigating the patterns in refraction growth in Chinese children, and to explore the possible risk factors affecting the different components of progression, as defined by Principal Component Analysis (PCA). A total of 637 first-born twins in Guangzhou Twin Eye Study with 6-year annual visits (baseline age 7–15 years) were available in the analysis. Cluster 1 to 3 were classified after a partitioning clustering, representing stable, slow and fast progressing groups of refraction respectively. Baseline age and refraction, paternal refraction, maternal refraction and proportion of two myopic parents showed significant differences across the three groups. Three major components of progression were extracted using PCA: “Average refraction”, “Acceleration” and the combination of “Myopia stabilization” and “Late onset of refraction progress”. In regression models, younger children with more severe myopia were associated with larger “Acceleration”. The risk factors of “Acceleration” included change of height and weight, near work, and parental myopia, while female gender, change of height and weight were associated with “Stabilization”, and increased outdoor time was related to “Late onset of refraction progress”. We therefore concluded that genetic and environmental risk factors have different impacts on patterns of refraction progression. PMID:27874105

  1. Integration of growth and specification in chick wing digit-patterning.

    PubMed

    Towers, Matthew; Mahood, Ruth; Yin, Yili; Tickle, Cheryll

    2008-04-17

    In the classical model of chick wing digit-patterning, the polarizing region--a group of cells at the posterior margin of the early bud--produces a morphogen gradient, now known to be based on Sonic hedgehog (Shh), that progressively specifies anteroposterior positional identities in the posterior digit-forming region. Here we add an integral growth component to this model by showing that Shh-dependent proliferation of prospective digit progenitor cells is essential for specifying the complete pattern of digits across the anteroposterior axis. Inhibiting Shh signalling in early wing buds reduced anteroposterior expansion, and posterior digits were lost because all prospective digit precursors formed anterior structures. Inhibiting proliferation also irreversibly reduced anteroposterior expansion, but instead anterior digits were lost because all prospective digit precursors formed posterior structures. When proliferation recovered in such wings, Shh transcription was maintained for longer than normal, suggesting that duration of Shh expression is controlled by a mechanism that measures proliferation. Rescue experiments confirmed that Shh-dependent proliferation controls digit number during a discrete time-window in which Shh-dependent specification normally occurs. Our findings that Shh signalling has dual functions that can be temporally uncoupled have implications for understanding congenital and evolutionary digit reductions.

  2. Patterns of women׳s mood after delivery: a growth curve analysis.

    PubMed

    Buttner, Melissa M; Brock, Rebecca L; O'Hara, Michael W

    2015-03-15

    The course and predictors of women׳s mood following childbirth have informed clinically significant phenomena, such as postpartum depression (PPD), with some contradictory findings due to methodological limitations. It is important to further investigate mood during this unique period of time to inform assessment and improve interventions. Recently delivered mothers (n=216) recruited from the maternity unit at a University hospital completed sociodemographic questions and the Daily Experiences Questionnaire (DEQ), a measure of Negative Affect (NA) and Positive Affect (PA), for 10 consecutive days. The Structured Clinical Interview for DSM-IV was administered to assess postpartum depression diagnosis. Growth curve modeling (GCM) techniques revealed average trends in mood following delivery. NA changed in a curvilinear fashion with a peak at day 5. PA declined rapidly during the days immediately following delivery and then stabilized. Women diagnosed with PPD experienced higher overall levels of NA and lower levels of PA from delivery to 10 days postpartum. Patterns of mood varied as a function of neuroticism and several well-established sociodemographic variables. Small sample size and relatively few ethnic minority participants may affect generalizability of the findings. NA changed in a pattern consistent with the "peaking phenomenon". Well-established risk factors of the blues had significant associations with mood from delivery to day 10. Increased understanding into the nature of NA and PA in the early postpartum, and its role in identifying women susceptible to experiencing PPD, can inform screening and therapeutic interventions for PPD. Published by Elsevier B.V.

  3. Retrieving Clinical Evidence: A Comparison of PubMed and Google Scholar for Quick Clinical Searches

    PubMed Central

    Bejaimal, Shayna AD; Sontrop, Jessica M; Iansavichus, Arthur V; Haynes, R Brian; Weir, Matthew A; Garg, Amit X

    2013-01-01

    Background Physicians frequently search PubMed for information to guide patient care. More recently, Google Scholar has gained popularity as another freely accessible bibliographic database. Objective To compare the performance of searches in PubMed and Google Scholar. Methods We surveyed nephrologists (kidney specialists) and provided each with a unique clinical question derived from 100 renal therapy systematic reviews. Each physician provided the search terms they would type into a bibliographic database to locate evidence to answer the clinical question. We executed each of these searches in PubMed and Google Scholar and compared results for the first 40 records retrieved (equivalent to 2 default search pages in PubMed). We evaluated the recall (proportion of relevant articles found) and precision (ratio of relevant to nonrelevant articles) of the searches performed in PubMed and Google Scholar. Primary studies included in the systematic reviews served as the reference standard for relevant articles. We further documented whether relevant articles were available as free full-texts. Results Compared with PubMed, the average search in Google Scholar retrieved twice as many relevant articles (PubMed: 11%; Google Scholar: 22%; P<.001). Precision was similar in both databases (PubMed: 6%; Google Scholar: 8%; P=.07). Google Scholar provided significantly greater access to free full-text publications (PubMed: 5%; Google Scholar: 14%; P<.001). Conclusions For quick clinical searches, Google Scholar returns twice as many relevant articles as PubMed and provides greater access to free full-text articles. PMID:23948488

  4. Seed storage conditions change the germination pattern of clonal growth plants in Mediterranean salt marshes

    USGS Publications Warehouse

    Espinar, J.L.; Garcia, L.V.; Clemente, L.

    2005-01-01

    The effect of salinity level and extended exposure to different salinity and flooding conditions on germination patterns of three saltmarsh clonal growth plants (Juncus subulatus, Scirpus litoralis, and S. maritimus) was studied. Seed exposure to extended flooding and saline conditions significantly affected the outcome of the germination process in a different, though predictable, way for each species, after favorable conditions for germination were restored. Tolerance of the germination process was related to the average salinity level measured during the growth/germination season at sites where established individuals of each species dominated the species cover. No relationship was found between salinity tolerance of the germination process and seed response to extended exposure to flooding and salinity conditions. The salinity response was significantly related to the conditions prevailing in the habitats of the respective species during the unfavorable (nongrowth/nongermination) season. Our results indicate that changes in salinity and hydrology while seeds are dormant affect the outcome of the seed-bank response, even when conditions at germination are identical. Because these environmental-history-dependent responses differentially affect seed germination, seedling density, and probably sexual recruitment in the studied and related species, these influences should be considered for wetland restoration and management.

  5. Long bone histology and growth patterns in ankylosaurs: implications for life history and evolution.

    PubMed

    Stein, Martina; Hayashi, Shoji; Sander, P Martin

    2013-01-01

    The ankylosaurs are one of the major dinosaur groups and are characterized by unique body armor. Previous studies on other dinosaur taxa have revealed growth patterns, life history and evolutionary mechanisms based on their long bone histology. However, to date nothing is known about long bone histology in the Ankylosauria. This study is the first description of ankylosaurian long bone histology based on several limb elements, which were sampled from different individuals from the Ankylosauridae and Nodosauridae. The histology is compared to that of other dinosaur groups, including other Thyreophora and Sauropodomorpha. Ankylosaur long bone histology is characterized by a fibrolamellar bone architecture. The bone matrix type in ankylosaurs is closest to that of Stegosaurus. A distinctive mixture of woven and parallel-fibered bone together with overall poor vascularization indicates slow growth rates compared to other dinosaurian taxa. Another peculiar characteristic of ankylosaur bone histology is the extensive remodeling in derived North American taxa. In contrast to other taxa, ankylosaurs substitute large amounts of their primary tissue early in ontogeny. This anomaly may be linked to the late ossification of the ankylosaurian body armor. Metabolically driven remodeling processes must have liberated calcium to ossify the protective osteodermal structures in juveniles to subadult stages, which led to further remodeling due to increased mechanical loading. Abundant structural fibers observed in the primary bone and even in remodeled bone may have improved the mechanical properties of the Haversian bone.

  6. Effect of ultraviolet light on topical minoxidil-induced hair growth in advanced male pattern baldness.

    PubMed

    Pestana, A; Olsen, E A; Delong, E R; Murray, J C

    1987-05-01

    Nine healthy men with type IVa or Va male pattern baldness completed a 4-month single-blinded controlled pilot study designed to assess the effect of ultraviolet light (UVL) on topical minoxidil-induced hair growth. Subjects applied 2% topical minoxidil solution twice daily to their balding scalps and to one target area on the upper arm. These men, all of whom had either skin type II or III, were randomized to also receive either incremental doses of UVB or PUVA (topical psoralen) twice weekly to one side of their scalp and to a 2.5 cm target area on the nonminoxidil-treated upper ipsilateral arm. Vellus, nonvellus, and total hair counts were done in two 1-inch in diameter circular target areas in symmetric regions of the scalp and on each upper arm at regular intervals. All nine subjects had an increase in target nonvellus hair and a net loss of vellus hair in scalp target area treated with topical minoxidil. Concomitant UVL did not have a significant synergistic nor adverse effect on topical minoxidil-induced hair growth.

  7. Landscape analysis of urban growth patterns in Seremban, Malaysia, using spatio-temporal data

    NASA Astrophysics Data System (ADS)

    Aburas, Maher M.; Abdullah, Sabrina H.; Ramli, Mohammad F.; As'shari, Zulfa H.

    2016-06-01

    Urban growth is one of the major issues that have played a significant role in destroying the ecosystem in recent years. Landscape analysis is an important technique widely used to evaluate urban growth patterns. In this study, four land-use maps from 1984, 1990, 2000, and 2010 have been used to analyze an urban landscape. The values of a built-up area were initially computed using a geographic information system environment based on the spatial gradient approach. Mathematical matrices were then used to determine the amount of change in urban patches in each direction. Results of the number of patches, landscape shape index, aggregation index, and total edges confirmed that the urban patches in Seremban, Malaysia, have become more dispersed from 2000 to 2010. The urban patches have also become more continuous, especially in the north-western part of Seremban as a result of the urban development in the Nilai District. These results indicate the necessity to create new policies in the city to protect the sustainability of the land use of Seremban.

  8. Long Bone Histology and Growth Patterns in Ankylosaurs: Implications for Life History and Evolution

    PubMed Central

    Stein, Martina; Hayashi, Shoji; Sander, P. Martin

    2013-01-01

    The ankylosaurs are one of the major dinosaur groups and are characterized by unique body armor. Previous studies on other dinosaur taxa have revealed growth patterns, life history and evolutionary mechanisms based on their long bone histology. However, to date nothing is known about long bone histology in the Ankylosauria. This study is the first description of ankylosaurian long bone histology based on several limb elements, which were sampled from different individuals from the Ankylosauridae and Nodosauridae. The histology is compared to that of other dinosaur groups, including other Thyreophora and Sauropodomorpha. Ankylosaur long bone histology is characterized by a fibrolamellar bone architecture. The bone matrix type in ankylosaurs is closest to that of Stegosaurus. A distinctive mixture of woven and parallel-fibered bone together with overall poor vascularization indicates slow growth rates compared to other dinosaurian taxa. Another peculiar characteristic of ankylosaur bone histology is the extensive remodeling in derived North American taxa. In contrast to other taxa, ankylosaurs substitute large amounts of their primary tissue early in ontogeny. This anomaly may be linked to the late ossification of the ankylosaurian body armor. Metabolically driven remodeling processes must have liberated calcium to ossify the protective osteodermal structures in juveniles to subadult stages, which led to further remodeling due to increased mechanical loading. Abundant structural fibers observed in the primary bone and even in remodeled bone may have improved the mechanical properties of the Haversian bone. PMID:23894321

  9. Clinical Features of Congenital Adrenal Insufficiency Including Growth Patterns and Significance of ACTH Stimulation Test

    PubMed Central

    Koh, Ji Won; Kim, Gu Hwan; Yoo, Han Wook

    2013-01-01

    Congenital adrenal insufficiency is caused by specific genetic mutations. Early suspicion and definite diagnosis are crucial because the disease can precipitate a life-threatening hypovolemic shock without prompt treatment. This study was designed to understand the clinical manifestations including growth patterns and to find the usefulness of ACTH stimulation test. Sixteen patients with confirmed genotyping were subdivided into three groups according to the genetic study results: congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH, n=11), congenital lipoid adrenal hyperplasia (n=3) and X-linked adrenal hypoplasia congenita (n=2). Bone age advancement was prominent in patients with CAH especially after 60 months of chronologic age (n=6, 67%). They were diagnosed in older ages in group with bone age advancement (P<0.05). Comorbid conditions such as obesity, mental retardation, and central precocious puberty were also prominent in this group. In conclusion, this study showed the importance of understanding the clinical symptoms as well as genetic analysis for early diagnosis and management of congenital adrenal insufficiency. ACTH stimulation test played an important role to support the diagnosis and serum 17-hydroxyprogesterone levels were significantly elevated in all of the CAH patients. The test will be important for monitoring growth and puberty during follow up of patients with congenital adrenal insufficiency. PMID:24265530

  10. Clinical features of congenital adrenal insufficiency including growth patterns and significance of ACTH stimulation test.

    PubMed

    Koh, Ji Won; Kim, Gu Hwan; Yoo, Han Wook; Yu, Jeesuk

    2013-11-01

    Congenital adrenal insufficiency is caused by specific genetic mutations. Early suspicion and definite diagnosis are crucial because the disease can precipitate a life-threatening hypovolemic shock without prompt treatment. This study was designed to understand the clinical manifestations including growth patterns and to find the usefulness of ACTH stimulation test. Sixteen patients with confirmed genotyping were subdivided into three groups according to the genetic study results: congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH, n=11), congenital lipoid adrenal hyperplasia (n=3) and X-linked adrenal hypoplasia congenita (n=2). Bone age advancement was prominent in patients with CAH especially after 60 months of chronologic age (n=6, 67%). They were diagnosed in older ages in group with bone age advancement (P<0.05). Comorbid conditions such as obesity, mental retardation, and central precocious puberty were also prominent in this group. In conclusion, this study showed the importance of understanding the clinical symptoms as well as genetic analysis for early diagnosis and management of congenital adrenal insufficiency. ACTH stimulation test played an important role to support the diagnosis and serum 17-hydroxyprogesterone levels were significantly elevated in all of the CAH patients. The test will be important for monitoring growth and puberty during follow up of patients with congenital adrenal insufficiency.

  11. Monitoring of Water Spectral Pattern Reveals Differences in Probiotics Growth When Used for Rapid Bacteria Selection

    PubMed Central

    Slavchev, Aleksandar; Kovacs, Zoltan; Koshiba, Haruki; Nagai, Airi; Bázár, György; Krastanov, Albert; Kubota, Yousuke; Tsenkova, Roumiana

    2015-01-01

    Development of efficient screening method coupled with cell functionality evaluation is highly needed in contemporary microbiology. The presented novel concept and fast non-destructive method brings in to play the water spectral pattern of the solution as a molecular fingerprint of the cell culture system. To elucidate the concept, NIR spectroscopy with Aquaphotomics were applied to monitor the growth of sixteen Lactobacillus bulgaricus one Lactobacillus pentosus and one Lactobacillus gasseri bacteria strains. Their growth rate, maximal optical density, low pH and bile tolerances were measured and further used as a reference data for analysis of the simultaneously acquired spectral data. The acquired spectral data in the region of 1100-1850nm was subjected to various multivariate data analyses – PCA, OPLS-DA, PLSR. The results showed high accuracy of bacteria strains classification according to their probiotic strength. Most informative spectral fingerprints covered the first overtone of water, emphasizing the relation of water molecular system to cell functionality. PMID:26133176

  12. Controlling growth and electrical connectivity of neuronal cells patterned on surfaces

    NASA Astrophysics Data System (ADS)

    Beighley, Ross; Spedden, Elise; White, James; Staii, Cristian

    2012-02-01

    In the developing brain biochemical and geometrical cues are an essential source of information used by neurons when wiring up the nervous system. However, our current understanding of the mechanisms by which various guidance factors control the path that growing axons/dendrites follow to reach their targets and form functional electrical connections remains qualitative. A current limitation for the study of neural network formation is the ability to precisely control the growth and interconnectivity of small numbers of neurons. Here we present a combined Atomic Force Microscopy - Fluorescence Spectroscopy approach for patterning neurons on 2-dimensional substrates and precisely controlling their location, growth and interconnectivity. We demonstrate that this approach allows one to: a) form simple neuronal circuits in well-controlled geometries; b) guide the formation of functional synapses between neurons, and c) measure the electrical activity of small groups of neurons. We also discuss the implications of these results for our current understanding of the fundamental mechanisms that govern the development of electrical connections between neurons.

  13. Contrasting mercury accumulation patterns in tilapia (Oreochromis niloticus) and implications on somatic growth dilution.

    PubMed

    Wang, Rui; Wang, Wen-Xiong

    2012-06-15

    Dietary ingestion constitutes a major pathway for mercury (Hg) accumulation in freshwater fish, thus the ingestion rate (IR) may greatly influence the Hg bioaccumulation through its effect on Hg influx and other biokinetic processes. To explore the complex influence of IR, we conducted long-term bioaccumulation experiments by accurately controlling the IRs in the freshwater tilapia (Oreochromis niloticus). The dietary accumulation of both inorganic mercury (Hg[II]) and methylmercury (MeHg) in tilapia under different IRs was monitored over a period of 30 days by feeding the fish with uniformly radiolabeled crustaceans. The biokinetic parameters under various IRs were concurrently determined. With the increase of IR from 0.01 g g⁻¹ d⁻¹ to 0.12 g g⁻¹ d⁻¹, the dietary assimilation efficiency of Hg(II) in the tilapia decreased by 43% while the elimination rate increased by a factor of 1.8; both biokinetic changes slowed down the overall Hg(II) bioaccumulation at high IRs. In contrast to Hg(II), the biokinetics of MeHg was not significantly influenced, but its bioaccumulation increased disproportionally with increasing IR, showing slower increase at higher IR. We then employed a biokinetic model to simulate the long-term mercury bioaccumulation patterns in tilapia at various IRs. The modeling results indicated that the growth effect could not be ignored in long-term accumulation process. A rapid growth of fish driven by food availability could significantly reduce the MeHg concentrations in the tilapia. Our results demonstrated for the first time the contrasting influences of dietary ingestion on the long-term bioaccumulation of Hg(II) and MeHg. The somatic growth dilution was much more likely to occur for MeHg than for Hg(II).

  14. Urban growth patterns in major Southeast Asian cities: Toward exposure mapping and vulnerability assessment

    NASA Astrophysics Data System (ADS)

    Mandapaka, Pradeep; Kamarajugedda, Shankar A.; Lo, Edmond Y. M.

    2017-04-01

    Southeast Asia (SEA) is undergoing rapid urbanization, with urban population percentage increasing from 32% in 1990 to 48% in 2015. It is projected that by the year 2040, urban regions in SEA account for 60% of its total population. The region is home to 600 million people, with many densely populated cities, including megacities such as Jakarta, Bangkok, and Manila. The region has more than 20,000 islands, and many cities lie on coastal low-lands and floodplains. These geographical characteristics together with the increasing population, infrastructure growth, and changing climate makes the region highly vulnerable to natural hazards. This study assessed urban growth dynamics in major (defined as population exceeding 1 million) SEA cities using remotely sensed night-time lights (NTL) data. A recently proposed brightness gradient approach was applied on 21 years (1992-2012) of NTL annual composites to derive core-urban (CU) and peri-urban (PU) regions within each city. The study also assessed the sensitivity of above extracted urban categories to different NTL thresholds. The temporal trends in CU and PU regions were quantified, and compared with trends in socio-economic indicators. The spatial expansion of CU and PU regions were found to depend on geographical constraints and socio-economic factors. Quantification of urban growth spatial-temporal patterns, as conducted here contributes towards the understanding of exposure and vulnerability of people and infrastructures to natural hazards, as well as the evolving trends for assessment under projected urbanization conditions. This will underpin better risk assessment efforts for present and future planning.

  15. Estimating Common Growth Patterns in Juvenile Chinook Salmon (Oncorhynchus tshawytscha) from Diverse Genetic Stocks and a Large Spatial Extent

    PubMed Central

    Scheuerell, Mark D.; Simenstad, Charles A.; Bottom, Daniel L.

    2016-01-01

    Life history variation in Pacific salmon (Oncorhynchus spp.) supports species resilience to natural disturbances and fishery exploitation. Within salmon species, life-history variation often manifests during freshwater and estuarine rearing, as variation in growth. To date, however, characterizing variability in growth patterns within and among individuals has been difficult via conventional sampling methods because of the inability to obtain repeated size measurements. In this study we related otolith microstructures to growth rates of individual juvenile Chinook salmon (O. tshawytscha) from the Columbia River estuary over a two-year period (2010–2012). We used dynamic factor analysis to determine whether there were common patterns in growth rates within juveniles based on their natal region, capture location habitat type, and whether they were wild or of hatchery origin. We identified up to five large-scale trends in juvenile growth rates depending on month and year of capture. We also found that hatchery fish had a narrower range of trend loadings for some capture groups, suggesting that hatchery fish do not express the same breadth of growth variability as wild fish. However, we were unable to resolve a relationship between specific growth patterns and habitat transitions. Our study exemplifies how a relatively new statistical analysis can be applied to dating or aging techniques to summarize individual variation, and characterize aspects of life history diversity. PMID:27695094

  16. Utilization and growth patterns of sacroiliac joint injections from 2000 to 2011 in the medicare population.

    PubMed

    Manchikanti, Laxmaiah; Hansen, Hans; Pampati, Vidyasagar; Falco, Frank J E

    2013-01-01

      The high prevalence of persistent low back pain and growing number of diagnostic and therapeutic modalities employed to manage chronic low back pain and the subsequent impact on society and the economy continue to hold sway over health care policy. Among the multiple causes responsible for chronic low back pain, the contributions of the sacroiliac joint have been a subject of debate albeit a paucity of research. At present, there are no definitive conservative, interventional or surgical management options for managing sacroiliac joint pain. It has been shown that the increases were highest for facet joint interventions and sacroiliac joint blocks with an increase of 310% per 100,000 Medicare beneficiaries from 2000 to 2011. There has not been a systematic assessment of the utilization and growth patterns of sacroiliac joint injections. Analysis of the growth patterns of sacroiliac joint injections in Medicare beneficiaries from 2000 to 2011. To evaluate the utilization and growth patterns of sacroiliac joint injections. This assessment was performed utilizing Centers for Medicare and Medicaid Services (CMS) Physician/Supplier Procedure Summary (PSPS) Master data from 2000 to 2011. The findings of this assessment in Medicare beneficiaries from 2000 to 2011 showed a 331% increase per 100,000 Medicare beneficiaries with an annual increase of 14.2%, compared to an increase in the Medicare population of 23% or annual increase of 1.9%. The number of procedures increased from 49,554 in 2000 to 252,654 in 2011, or a rate of 125 to 539 per 100,000 Medicare beneficiaries. Among the various specialists performing sacroiliac joint injections, physicians specializing in physical medicine and rehabilitation have shown the most increase, followed by neurology with 1,568% and 698%, even though many physicians from both specialties have been enrolling in interventional pain management and pain management. Even though the numbers were small for nonphysician providers including

  17. Patterned growth of ZnO nanowires on flexible substrates for enhanced performance of flexible piezoelectric nanogenerators

    NASA Astrophysics Data System (ADS)

    Yang, Dechao; Qiu, Yu; Jiang, Qingyu; Guo, Zhaoshuai; Song, Wenbin; Xu, Jin; Zong, Yang; Feng, Qiuxia; Sun, Xiaoling

    2017-02-01

    Flexible piezoelectric nanogenerators (NGs) based on patterned growth of ZnO nanowires (PNWs) by the hydrothermal method are proposed for high-efficiency energy harvesting applications. The use of the PNWs in ZnO-based FPNGs results in a significant improvement in terms of the magnitude of the output currents of up to 6 times when compared with pristine ZnO NW-based FPNGs without patterned growth mode. The maximum output current was measured to be about 150 nA, which was enough to drive some micro/nanoelectronic devices. The improved output performance is mainly attributed to the patterned growth mode in FPNGs, which may significantly reduce the piezoelectric potential screening effect caused by free electrons in ZnO. This strategy may provide a highly promising platform as energy harvesting devices for viable industrial applications in portable/wearable nanodevices.

  18. Micro-patterning of Mammalian Cells on Suspended MEMS Resonant Sensors for Long-Term Growth Measurements

    PubMed Central

    Corbin, Elise A.; Dorvel, Brian R.; Millet, Larry J.; King, William P.; Bashir, Rashid

    2014-01-01

    MEMS resonant mass sensors can measure the mass of individual cells, though long-term growth measurements are limited by the movement of cells off the sensor area. Micro-patterning techniques are a powerful approach to control the placement of individual cells in an arrayed format. In this work we present a method for micro-patterning cells on fully suspended resonant sensors through select functionalization and passivation of the chip surface. This method combines high-resolution photolithography with a blanket transfer technique for applying photoresist to avoid damaging the sensors. Cells are constrained to the patterned collagen area on the sensor by pluronic acting as a cell adhesion blocker. This micro-patterning method enables long-term growth measurements, which is demonstrated by a measurement of the change in mass of a human breast cancer cell over 18 h. PMID:24535001

  19. Epitaxial Growth of Silicon Films on SiO2 Patterned Si(100) Substrates by Atmospheric Pressure Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Duan, Chunyan; Deng, Youjun; Ai, Bin; Liu, Chao; Zhuang, Lin; Shen, Hui

    2012-09-01

    In order to investigate the effect of selective area nucleation on epitaxial growth of silicon (Si) films, 35 µm thick Si films were deposited by atmospheric pressure chemical vapor deposition (APCVD) under the standard condition on two kinds of SiO2 patterned Si(100) wafers. One was circular patterns, and the other was striated patterns. Then, the structural properties of the as-deposited silicon thin films were investigated by metallurgical microscope, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (TEM). The results show that normal epitaxial growth occurs on the exposed Si(100) regions, while just polycrystalline Si deposition happens on the SiO2 regions. Moreover, for the substrates with circular patterns, the as-deposited Si thin films possess pyramid surface morphology thus excellent light trapping performance being spontaneously formed, and the sizes of the pyramid grains approximately equal to the sum of the diameter and spacing of the round exposed Si regions.

  20. Quantity and quality assessment of randomized controlled trials on orthodontic practice in PubMed.

    PubMed

    Shimada, Tatsuo; Takayama, Hisako; Nakamura, Yoshiki

    2010-07-01

    To find current high-quality evidence for orthodontic practice within a reasonable time, we tested the performance of a PubMed search. PubMed was searched using publication type randomized controlled trial and medical subject heading term "orthodontics" for articles published between 2003 and 2007. The PubMed search results were compared with those from a hand search of four orthodontic journals to determine the sensitivity of PubMed search. We evaluated the precision of the PubMed search result and assessed the quality of individual randomized controlled trials using the Jadad scale. Sensitivity and precision were 97.46% and 58.12%, respectively. In PubMed, of the 277 articles retrieved, 161 (58.12%) were randomized controlled trials on orthodontic practice, and 115 of the 161 articles (71.42%) were published in four orthodontic journals: American Journal of Orthodontics and Dentofacial Orthopedics, The Angle Orthodontist, the European Journal of Orthodontics, and the Journal of Orthodontics. Assessment by the Jadad scale revealed 60 high-quality randomized controlled trials on orthodontic practice, of which 45 (75%) were published in these four journals. PubMed is a highly desirable search engine for evidence-based orthodontic practice. To stay current and get high-quality evidence, it is reasonable to look through four orthodontic journals: American Journal of Orthodontics and Dentofacial Orthopedics, The Angle Orthodontist, the European Journal of Orthodontics, and the Journal of Orthodontics.

  1. Epitaxial graphene growth on FIB patterned 3C-SiC nanostructures on Si (111): reducing milling damage.

    PubMed

    Amjadipour, Mojtaba; MacLeod, Jennifer; Lipton-Duffin, Josh; Iacopi, Francesca; Motta, Nunzio

    2017-08-25

    Epitaxial growth of graphene on SiC is a scalable procedure that does not require any further transfer step, making this an ideal platform for graphene nanostructure fabrication. Focused ion beam (FIB) is a very promising tool for exploring the reduction of the lateral dimension of graphene on SiC to the nanometre scale. However, exposure of graphene to the Ga(+) beam causes significant surface damage through amorphisation and contamination, preventing epitaxial graphene growth. In this paper we demonstrate that combining a protective silicon layer with FIB patterning implemented prior to graphene growth can significantly reduce the damage associated with FIB milling. Using this approach, we successfully achieved graphene growth over 3C-SiC/Si FIB patterned nanostructures.

  2. Epitaxial graphene growth on FIB patterned 3C-SiC nanostructures on Si (111): reducing milling damage

    NASA Astrophysics Data System (ADS)

    Amjadipour, Mojtaba; MacLeod, Jennifer; Lipton-Duffin, Josh; Iacopi, Francesca; Motta, Nunzio

    2017-08-01

    Epitaxial growth of graphene on SiC is a scalable procedure that does not require any further transfer step, making this an ideal platform for graphene nanostructure fabrication. Focused ion beam (FIB) is a very promising tool for exploring the reduction of the lateral dimension of graphene on SiC to the nanometre scale. However, exposure of graphene to the Ga+ beam causes significant surface damage through amorphisation and contamination, preventing epitaxial graphene growth. In this paper we demonstrate that combining a protective silicon layer with FIB patterning implemented prior to graphene growth can significantly reduce the damage associated with FIB milling. Using this approach, we successfully achieved graphene growth over 3C-SiC/Si FIB patterned nanostructures.

  3. Patterns of growth dominance in forests of the Rocky Mountains, USA

    Treesearch

    Dan Binkley; Daniel M. Kashian; Suzanne Boyden; Margot W. Kaye; John B. Bradford; Mary A. Arthur; Paula J. Fornwalt; Michael G. Ryan

    2006-01-01

    We used data from 142 stands in Colorado andWyoming, USA, to test the expectations of a model of growth dominance and stand development. Growth dominance relates the distribution of growth rates of individual trees within a stand to tree sizes. Stands with large trees that account for a greater share of stand growth than of stand mass exhibit strong growth dominance....

  4. Neurilemmoma showing a unique growth pattern in the lateral chest wall: both inside and outside the thoracic cavity.

    PubMed

    Jun Ahn, Sun; Joo Park, Kyung; Sung Sun, Joo; Choi, Ho; Hee Lee, Yong

    2014-01-01

    We report the first case of the intercostal neurilemmoma showing a unique growth pattern in the lateral chest wall (both inside and outside the thoracic cavity). Usually, intrathoracic neurilemmoma is found in the posterior mediastinum and bulge from the inner surface of the bony thorax toward the thoracic cavity. This unique growing pattern of neurilemmoma arising from intercostal nerve was clearly demonstrated by computed tomography and ultrasonography.

  5. Blanket and Patterned Growth of CdTe on (211)Si Substrates by Metal-Organic Vapor Phase Epitaxy

    DTIC Science & Technology

    2012-05-15

    dislocation density further, growth on patterned layer has been investigated using Si3N4 as the mask. 1. REPORT DATE (DD-MM-YYYY) 4 . TITLE AND...of America 19 Loveton Circle Hunt Valley Loveton Center Sparks, MD 21152 - 9201 REPORT DOCUMENTATION PAGE b. ABSTRACT UU c. THIS PAGE UU 2. REPORT...yet assigned; citable using Digital Object Identifier – DOI) Phys. Status Solidi C, 1– 4 (2012) / DOI 10.1002/pssc.201100765 Blanket and patterned

  6. Gender differences in scalp hair growth rates are maintained but reduced in pattern hair loss compared to controls.

    PubMed

    Van Neste, D J J; Rushton, D H

    2016-08-01

    Hair loss is related to follicular density, programmed regrowth and hair productivity. The dissatisfaction with hair growth in patients experiencing hair loss might be due to slower linear hair growth rate (LHGR). LHGR and hair diameter was evaluated in Caucasian controls and patients with patterned hair loss employing the validated non-invasive, contrast-enhanced-phototrichogram with exogen collection. We evaluated 59,765 anagen hairs (controls 24,609, patients 35,156) and found thinner hairs grew slower than thicker hairs. LHGR in normal women was generally higher than in normal men. LHGR correlates with hair diameter (P < 0.006) and global thinning is associated with slower growth rates. Compared with hair of equal thickness in controls, subjects affected with patterned hair loss showed reduced hair growth rates, an observation found in both male and female patients. Males with pattern hair loss showed further reduction in growth rates as clinical severity worsened. However, sample size limitations prevented statistical evaluation of LHGR in severely affected females. Caucasian ethnicity. In pattern hair loss, LHGR significantly contributes to the apparent decrease in hair volume in affected areas. In early onset, LHRG might have a prognostic value in females but not in males. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Analysis of changes in relative elemental growth rate patterns in the elongation zone of Arabidopsis roots upon gravistimulation

    NASA Technical Reports Server (NTRS)

    Mullen, J. L.; Ishikawa, H.; Evans, M. L.

    1998-01-01

    Although Arabidopsis is an important system for studying root physiology, the localized growth patterns of its roots have not been well defined, particularly during tropic responses. In order to characterize growth rate profiles along the apex of primary roots of Arabidopsis thaliana (L.) Heynh (ecotype Columbia) we applied small charcoal particles to the root surface and analyzed their displacement during growth using an automated video digitizer system with custom software for tracking the markers. When growing vertically, the maximum elongation rate occurred 481 +/- 50 microns back from the extreme tip of the root (tip of root cap), and the elongation zone extended back to 912 +/- 137 microns. The distal elongation zone (DEZ) has previously been described as the apical region of the elongation zone in which the relative elemental growth rate (REGR) is < or = 30% of the peak rate in the central elongation zone. By this definition, our data indicate that the basal limit of the DEZ was located 248 +/- 30 microns from the root tip. However, after gravistimulation, the growth patterns of the root changed. Within the first hour of graviresponse, the basal limit of the DEZ and the position of peak REGR shifted apically on the upper flank of the root. This was due to a combination of increased growth in the DEZ and growth inhibition in the central elongation zone. On the lower flank, the basal limit of the DEZ shifted basipetally as the REGR decreased. These factors set up the gradient of growth rate across the root, which drives curvature.

  8. Analysis of changes in relative elemental growth rate patterns in the elongation zone of Arabidopsis roots upon gravistimulation

    NASA Technical Reports Server (NTRS)

    Mullen, J. L.; Ishikawa, H.; Evans, M. L.

    1998-01-01

    Although Arabidopsis is an important system for studying root physiology, the localized growth patterns of its roots have not been well defined, particularly during tropic responses. In order to characterize growth rate profiles along the apex of primary roots of Arabidopsis thaliana (L.) Heynh (ecotype Columbia) we applied small charcoal particles to the root surface and analyzed their displacement during growth using an automated video digitizer system with custom software for tracking the markers. When growing vertically, the maximum elongation rate occurred 481 +/- 50 microns back from the extreme tip of the root (tip of root cap), and the elongation zone extended back to 912 +/- 137 microns. The distal elongation zone (DEZ) has previously been described as the apical region of the elongation zone in which the relative elemental growth rate (REGR) is < or = 30% of the peak rate in the central elongation zone. By this definition, our data indicate that the basal limit of the DEZ was located 248 +/- 30 microns from the root tip. However, after gravistimulation, the growth patterns of the root changed. Within the first hour of graviresponse, the basal limit of the DEZ and the position of peak REGR shifted apically on the upper flank of the root. This was due to a combination of increased growth in the DEZ and growth inhibition in the central elongation zone. On the lower flank, the basal limit of the DEZ shifted basipetally as the REGR decreased. These factors set up the gradient of growth rate across the root, which drives curvature.

  9. Quertle and KNALIJ: searching PubMed has never been so easy and effective.

    PubMed

    Giglia, E

    2011-12-01

    Quertle and KNALIJ are two innovative tools created to search PubMed in a easier and more effective way. They dramatically reduce time to discover meaningful results. Quertle allows a semantic search in multiple biomedical databases (PubMed included) and runs a query via relationships between concepts, so that you retrieve at ease more pertinent results and can navigate them by "key concepts". KNALIJ is a visualization tool which searches PubMed and presents the results in the form of visual, interactive maps you can zoom, scale, and explore according to new paths.

  10. Automatic Export of PubMed Citations to EndNote.

    PubMed

    London, Sue; Gurdal, Osman; Gall, Carole

    2010-04-01

    The export of MEDLINE references to EndNote can be accomplished in various ways. Unlike Ovid MEDLINE, PubMed does not have a direct export feature to EndNote. Until recently, PubMed references had to be saved as a text file to import into EndNote. Now, the automatic export of PubMed references can be done using Internet Explorer (IE) or Mozilla Firefox Web browsers. The development and teaching of seamless citation management is a value-added service to health professionals.

  11. Photolithographically defined deposition of attachment factors as a versatile method for patterning the growth of different cell types in culture.

    PubMed

    Rohr, Stephan; Flückiger-Labrada, Regula; Kucera, Jan P

    2003-04-01

    Spatially defined growth of cells in culture is a useful model for studies ranging from the characterization of cellular motility to the analysis of network behaviour in structurally defined ensembles of excitable cells. Current methodological approaches for obtaining patterned growth include sophisticated modifications of surface chemistry, stamping techniques and microfluidics. The implementation of most of these techniques requires the availability of highly specialized apparatus and some of the methods are specific for certain cell types and/or substrate materials. The goal of the present study was to develop a cell-patterning technique that can be implemented by any laboratory working with cell culture and that is highly adaptable in terms of cell types and substrate materials. The method is based on a photolithographic process that permits the patterned deposition of attachment factors of choice on surfaces previously coated with agar with a spatial resolution (maximal deviation from a straight line) of +/-3 micro m. Because agar efficiently prevents cell adhesion, patterned growth obtained with this technique displays virtually no off-pattern cell attachment. The method permitted the patterning of cardiomyocytes, fibroblasts and HeLa cells on either glass substrates or polymer-coated materials with a spatial resolution of a few micrometers.

  12. Soil respiration in an old-growth subtropical forest: Patterns, components, and controls

    NASA Astrophysics Data System (ADS)

    Tan, Zheng-Hong; Zhang, Yi-Ping; Liang, Naishen; Song, Qing-Hai; Liu, Yu-Hong; You, Guang-Yong; Li, Lin-Hui; Yu, Lei; Wu, Chuan-Shen; Lu, Zhi-Yun; Wen, Han-Dong; Zhao, Jun-Fu; Gao, Fu; Yang, Lian-Yan; Song, Liang; Zhang, Yong-Jiang; Munemasa, Teramoto; Sha, Li-Qing

    2013-04-01

    The patterns, components, and controls of soil respiration in an old-growth subtropical forest were investigated using an automatic chamber system. We measured soil respiration in three treatments (control, trenching, litter removal) over 15 months. The annual total soil respiration (1248 gC m-2 yr-1) showed considerable spatial variation (coefficient of variation = 27.8%) within the forest. Thirty samples were required to obtain results within 10% of the mean value at a 95% confidential level. A distinctive cosine-like diel pattern of soil respiration was observed; the time lag between gross primary production and soil respiration at this scale was calculated to be 4-5 h. Seasonality of soil respiration was strong (~1 µmol m-2 s-1 near the end of winter; ~6 µmol m-2 s-1 in midsummer). No time lag was discerned between gross primary production and soil respiration at the seasonal scale. Soil temperature at 5 cm below surface can explain most (>91%) of the observed annual variation in soil respiration. The apparent respiration temperature sensitivity index (Q10) was 3.05. The lowest Q10 value was observed in winter, when soil moisture was low. Soil respiration was overestimated by a Q10 function during both dry and wet periods. The relative contributions of soil organic matter (RSOM), litterfall decomposition (RL), and root respiration (RR) to total soil respiration are 65.25%, 18.73%, and 16.01%, respectively; the temperature sensitivity of these components differ: RL (Q10 = 7.22) > RSOM (2.73) > RR (1.65). This relationship between Q10 values for litter respiration, soil organic matter decomposition, and root respiration still holds after minimizing the confounding effect of moisture. A relatively constant substrate supply and/or thermal acclimation could account for the observed low-temperature sensitivity in root respiration. Given the high carbon stocks and fluxes, the old-growth subtropical forests of China seem important in the global carbon budget and

  13. Patterns of Deregulation of Insulin Growth Factor Signaling Pathway in Pediatric and Adult Gastrointestinal Stromal Tumors

    PubMed Central

    Italiano, Antoine; Chen, Junwei; Zhang, Lei; Hajdu, Mihai; Singer, Samuel; DeMatteo, Ronald P; Antonescu, Cristina R.

    2013-01-01

    Background Data regarding the patterns and the mechanisms of deregulation of the insulin growth factor (IGF) pathway in adult and pediatric gastrointestinal stromal tumors (GISTs) are limited. Methods We investigated the expression profiling of the genes encoding the main components of the IGF signaling pathway in 131 GISTs (106 adult, 21 pediatric and 4 young adult) and 25 other soft-tissue sarcomas (STS) using an Affymetrix U133A platform. IGF2 was investigated for loss of imprinting (LOI) whereas IGF1R was analyzed for copy number aberration and mutation. Results IGF2 was the most highly overexpressed gene of the IGF pathway in GIST. IGF2 expression was also significantly higher than in other STS. IGF2 expression was correlated to the age onset and mutational status of GIST. Indeed, IGF2 expression was significantly higher in the “adult” group than in the “pediatric” and “young adult” groups. Among adult GIST, IGF2 expression was higher in tumors lacking KIT or PDGFRA mutations in comparison with mutated cases. A trend for a higher expression of IGF2 in resistant GIST in comparison to responsive GIST was also found. Overexpression of IGF2 was not related to LOI. Conversely, the expression of the IGF1R gene was significantly higher in the pediatric group than in the adult group. No copy number gains or mutations of IGF1R were observed. Conclusion The IGF pathway is deregulated in GIST with distinct patterns according to age onset and mutational status. The IGF pathway may represent a therapeutic target in patients with primary or secondary resistance to imatinib. PMID:22770876

  14. Patterns of vertical facial growth in Korean adolescents analyzed with mixed-effects regression analysis.

    PubMed

    Moon, Sung-Chul; Kim, Hong-Kyun; Kwon, Taek-Ka; Han, Seong Ho; An, Chang-Hyeon; Park, Young-Seok

    2013-06-01

    To understand the growth patterns of skeletal open bite and deepbite, we present observations from 9 years of pure longitudinal data based on lateral cephalometric radiographs using mixed-effects regression model analysis. In total, 51 children (14 years old) with extreme values for the ratio of lower anterior facial height to total anterior facial height were assigned to 1 of 2 groups: a skeletal open-bite group (11 boys, 14 girls) or a skeletal deepbite group (14 boys, 12 girls). Measurements of total anterior facial height, upper anterior facial height, lower anterior facial height, total posterior facial height, ramus height, and ratio of lower anterior facial height to total anterior facial height were obtained for all subjects. All data were analyzed and interpreted using a mixed-effects regression model analysis with random effects. From these 4 groups at 14 years old, statistically significant differences were observed between the groups when subjects of the same sex were compared; however, statistical significance was not reached between subjects of opposite sexes in each group. Morphologic differences were clearly evident from the start and became more pronounced with age. There were statistical significances in the initial values and increases with age in all 6 variables except for increases with age in the ratio of lower anterior facial height to total anterior facial height. Statistical significance was also reached for morphologic differences between the annual increases in the ratio of lower anterior facial height to total anterior facial height and lower anterior facial height. In general, individual random variability was high in all variables when compared with the annual changes over time. Divergent patterns were established early and became more pronounced with age, with anterior facial height dimensions primarily contributing to these differences. Individual variations were so pronounced that caution is recommended for all clinical decisions

  15. A comparison of postnatal arterial patterns in a growth series of giraffe (Artiodactyla: Giraffa camelopardalis).

    PubMed

    O'Brien, Haley D; Gignac, Paul M; Hieronymus, Tobin L; Witmer, Lawrence M

    2016-01-01

    Nearly all living artiodactyls (even-toed ungulates) possess a derived cranial arterial pattern that is highly distinctive from most other mammals. Foremost among a suite of atypical arterial configurations is the functional and anatomical replacement of the internal carotid artery with an extensive, subdural arterial meshwork called the carotid rete. This interdigitating network branches from the maxillary artery and is housed within the cavernous venous sinus. As the cavernous sinus receives cooled blood draining from the nasal mucosa, heat rapidly dissipates across the high surface area of the rete to be carried away from the brain by the venous system. This combination yields one of the most effective mechanisms of selective brain cooling. Although arterial development begins from the same embryonic scaffolding typical of mammals, possession of a rete is typically accompanied by obliteration of the internal carotid artery. Among taxa with available ontogenetic data, the point at which the internal carotid obliterates is variable throughout development. In small-bodied artiodactyls, the internal carotid typically obliterates prior to parturition, but in larger species, the vessel may remain patent for several years. In this study, we use digital anatomical data collection methods to describe the cranial arterial patterns for a growth series of giraffe (Giraffa camelopardalis), from parturition to senescence. Giraffes, in particular, have unique cardiovascular demands and adaptations owing to their exceptional body form and may not adhere to previously documented stages of cranial arterial development. We find the carotid arterial system to be conserved between developmental stages and that obliteration of the giraffe internal carotid artery occurs prior to parturition.

  16. A comparison of postnatal arterial patterns in a growth series of giraffe (Artiodactyla: Giraffa camelopardalis)

    PubMed Central

    Gignac, Paul M.; Hieronymus, Tobin L.; Witmer, Lawrence M.

    2016-01-01

    Nearly all living artiodactyls (even-toed ungulates) possess a derived cranial arterial pattern that is highly distinctive from most other mammals. Foremost among a suite of atypical arterial configurations is the functional and anatomical replacement of the internal carotid artery with an extensive, subdural arterial meshwork called the carotid rete. This interdigitating network branches from the maxillary artery and is housed within the cavernous venous sinus. As the cavernous sinus receives cooled blood draining from the nasal mucosa, heat rapidly dissipates across the high surface area of the rete to be carried away from the brain by the venous system. This combination yields one of the most effective mechanisms of selective brain cooling. Although arterial development begins from the same embryonic scaffolding typical of mammals, possession of a rete is typically accompanied by obliteration of the internal carotid artery. Among taxa with available ontogenetic data, the point at which the internal carotid obliterates is variable throughout development. In small-bodied artiodactyls, the internal carotid typically obliterates prior to parturition, but in larger species, the vessel may remain patent for several years. In this study, we use digital anatomical data collection methods to describe the cranial arterial patterns for a growth series of giraffe (Giraffa camelopardalis), from parturition to senescence. Giraffes, in particular, have unique cardiovascular demands and adaptations owing to their exceptional body form and may not adhere to previously documented stages of cranial arterial development. We find the carotid arterial system to be conserved between developmental stages and that obliteration of the giraffe internal carotid artery occurs prior to parturition. PMID:26925324

  17. Multiple births in sub-saharan Africa: epidemiology, postnatal survival, and growth pattern.

    PubMed

    Gebremedhin, Samson

    2015-02-01

    The study endeavored to assess the epidemiology, postnatal survival, and growth pattern of multiple births in Sub-Saharan Africa (SSA). It was based on the data of 25 demographic health surveys conducted in the subcontinent since 2008. The records of 213,889 children born in the preceding 59 months of the surveys were included. The multiple birth rate was computed as the number of multiple confinements per 1,000 births. Factors associated with multiple births were identified using logistic regression and their survival pattern was assessed using the Kaplan-Meier method. The multiple birth rate was 17.1 (95% confidence interval: 17.7-16.6) and showed considerable variation across the 25 countries included in the study. Odds of multiple births were significantly increased with advanced maternal age, parity, and maternal height but not with wealth index, age at first birth, and month of birth. At the end of the fourth year of age, the cumulative survival probability was as low as 0.77 in multiple births as compared to 0.93 in their counterparts. The odds of neonatal, infant and under-five mortality were 5.55, 4.39, and 3.72 times increased in multiple births, respectively. Multiple births tend to be malnourished than singletons and the odds of wasting, stunting, and underweight were 1.31, 1.83, and 1.73 times raised, consecutively. Nevertheless, multiple births regain their weight-for-age (WFA) and height-for-age (HFA) deficits by the end of the fourth year of age. Counseling pregnant mothers with multiple gestation to give birth at a health institution and providing close medical follow-up during and after the neonatal period can improve the survival of multiple births.

  18. Patterns of metal accumulation by natural river biofilms during their growth and seasonal succession.

    PubMed

    Tien, Chien-Jung; Chen, Colin S

    2013-05-01

    To evaluate the factors influencing patterns of metal accumulation by river biofilms, concentrations of chromium (Cr), nickel (Ni), copper (Cu), and lead (Pb) in biofilms from Erh-Jen River and San-Yeh-Kung Creek were investigated during their growth and seasonal succession. Different metal-accumulation patterns during biofilm development were observed between the two rivers. Mature biofilms (grown for 21-28 days) in both rivers showed maximum metal accumulation (≤3.24 × 10(4), 1.55 × 10(4), 7.40 × 10(3), and 7.80 × 10(2) μg g(-1) of Cr, Ni, Cu, and Pb, respectively) and bioconcentration factors (≤7.15 × 10(5), 1.60 × 10(5), 2.60 × 10(5), and 4.22 × 10(5) l kg(-1) of Cr, Ni, Cu, and Pb, respectively). These types of biofilms had the characteristics of being good metal accumulators and the ability to integrate metal-exposure conditions, suggesting that they were suitable biomonitors for metal-contaminated water. Seasonal succession in metal-accumulation ability of 1-month-old biofilms from Erh-Jen River was mainly affected by changes in bacterial and algal biomass and chemical oxygen demand in water, whereas that from San-Yeh-Kung Creek was primary influenced by concentrations of total nitrogen in water. Synergistic interaction between these four metals on metal-binding sites within biofilms was also shown.

  19. Impact of fertilizing pattern on the biodiversity of a weed community and wheat growth.

    PubMed

    Tang, Leilei; Cheng, Chuanpeng; Wan, Kaiyuan; Li, Ruhai; Wang, Daozhong; Tao, Yong; Pan, Junfeng; Xie, Juan; Chen, Fang

    2014-01-01

    Weeding and fertilization are important farming practices. Integrated weed management should protect or improve the biodiversity of farmland weed communities for a better ecological environment with not only increased crop yield, but also reduced use of herbicides. This study hypothesized that appropriate fertilization would benefit both crop growth and the biodiversity of farmland weed communities. To study the effects of different fertilizing patterns on the biodiversity of a farmland weed community and their adaptive mechanisms, indices of species diversity and responses of weed species and wheat were investigated in a 17-year field trial with a winter wheat-soybean rotation. This long term field trial includes six fertilizing treatments with different N, P and K application rates. The results indicated that wheat and the four prevalent weed species (Galium aparine, Vicia sativa, Veronica persica and Geranium carolinianum) showed different responses to fertilizer treatment in terms of density, plant height, shoot biomass, and nutrient accumulations. Each individual weed population exhibited its own adaptive mechanisms, such as increased internode length for growth advantages and increased light interception. The PK treatment had higher density, shoot biomass, Shannon-Wiener and Pielou Indices of weed community than N plus P fertilizer treatments. The N1/2PK treatment showed the same weed species number as the PK treatment. It also showed higher Shannon-Wiener and Pielou Indices of the weed community, although it had a lower wheat yield than the NPK treatment. The negative effects of the N1/2PK treatment on wheat yield could be balanced by the simultaneous positive effects on weed communities, which are intermediate in terms of the effects on wheat and weeds.

  20. Impact of Fertilizing Pattern on the Biodiversity of a Weed Community and Wheat Growth

    PubMed Central

    Tang, Leilei; Cheng, Chuanpeng; Wan, Kaiyuan; Li, Ruhai; Wang, Daozhong; Tao, Yong; Pan, Junfeng; Xie, Juan; Chen, Fang

    2014-01-01

    Weeding and fertilization are important farming practices. Integrated weed management should protect or improve the biodiversity of farmland weed communities for a better ecological environment with not only increased crop yield, but also reduced use of herbicides. This study hypothesized that appropriate fertilization would benefit both crop growth and the biodiversity of farmland weed communities. To study the effects of different fertilizing patterns on the biodiversity of a farmland weed community and their adaptive mechanisms, indices of species diversity and responses of weed species and wheat were investigated in a 17-year field trial with a winter wheat-soybean rotation. This long term field trial includes six fertilizing treatments with different N, P and K application rates. The results indicated that wheat and the four prevalent weed species (Galium aparine, Vicia sativa, Veronica persica and Geranium carolinianum) showed different responses to fertilizer treatment in terms of density, plant height, shoot biomass, and nutrient accumulations. Each individual weed population exhibited its own adaptive mechanisms, such as increased internode length for growth advantages and increased light interception. The PK treatment had higher density, shoot biomass, Shannon-Wiener and Pielou Indices of weed community than N plus P fertilizer treatments. The N1/2PK treatment showed the same weed species number as the PK treatment. It also showed higher Shannon-Wiener and Pielou Indices of the weed community, although it had a lower wheat yield than the NPK treatment. The negative effects of the N1/2PK treatment on wheat yield could be balanced by the simultaneous positive effects on weed communities, which are intermediate in terms of the effects on wheat and weeds. PMID:24416223

  1. Feeding symptoms, dietary patterns, and growth in young children with autism spectrum disorders.

    PubMed

    Emond, Alan; Emmett, Pauline; Steer, Colin; Golding, Jean

    2010-08-01

    To investigate the feeding, diet and growth of young children with autism spectrum disorders (ASD). Data on feeding and food frequency were collected by questionnaires completed at 6, 15, 24, 38 and 54 months by participants in the Avon Longitudinal Study of Parents and Children. A food variety score was created, and the content of the diet was calculated at 38 m. The feeding and dietary patterns of 79 children with ASD were compared with 12 901 controls. The median ages of ASD children were 28 months at referral and 45 months at diagnosis. ASD infants showed late introduction of solids after 6 months (p = .004) and were described as "slow feeders" at 6 months (p = .04). From 15-54 months ASD children were consistently reported to be "difficult to feed" (p < .001) and "very choosy" (p < .001). From 15 months, the ASD group had a less varied diet than controls, were more likely to have different meals from their mother from 24 months, and by 54 months 8% of ASD children were taking a special diet for "allergy." ASD children consumed less vegetables, salad and fresh fruit, but also less sweets and fizzy drinks. At 38 months intakes of energy, total fat, carbohydrate and protein were similar, but the ASD group consumed less vitamins C (p = .02) and D (p = .003). There were no differences in weight, height or BMI at 18 months and 7 years, or in hemoglobin concentrations at 7 years. ASD children showed feeding symptoms from infancy and had a less varied diet from 15 months, but energy intake and growth were not impaired.

  2. The influence of infant feeding patterns on growth of children in American Samoa.

    PubMed

    Bindon, J R

    1985-01-01

    This paper examines the trends in infant feeding practices in American Samoa and analyzes the relationship between infant feeding and growth among children born in American Samoa from 1976 to 1982. The study population is composed of the Polynesian inhabitants of the islands comprising the Territory of American Samoa. The sample is drawn from the records of the Well Baby Clinic in American Samoa. Feeding habit information and health of the infant was solicited by the nurses and doctor during clinic visits. The mothers were questioned about the child's diet. About 40% of the infants were exclusively breastfed; 13% had bottle supplements; 6% were classified as milk drinkers; and 40% were formula-fed. Frequently more than 1 feeding pattern was noted for a given child. Feeding influences were found to be significant on weight up to age 4, and height up to age 3. The timing of the introduction of solids was found to have a significant relationship with length through age 2. There appears to be a complex set of interactions between socioeconomic, growth and health factors. Mothers wean children early to return of work. This results from the availability of infant formula in Samoan stores, more jobs for women and the desire to improve socioeconomic status. Bottlefed infants of working mothers are more likely to have gastrointestinal problems than other infants. As a group, however, bottlefed infants are likely to have higher weights. The most significant contributing factor to morbidity and mortality among adults in American Samoa is the high prevalence of obesity. Extended breastfeeding of the infant can promote health in infancy and in later years.

  3. Patterns of brain angiogenesis after vascular endothelial growth factor administration in vitro and in vivo

    PubMed Central

    Rosenstein, Jeffrey M.; Mani, Nina; Silverman, William F.; Krum, Janette M.

    1998-01-01

    Vascular endothelial growth factor (VEGF) is a secreted endothelial cell mitogen that has been shown to induce vasculogenesis and angiogenesis in many organ systems and tumors. Considering the importance of VEGF to embryonic vascularization and survival, the effects of administered VEGF on developing or adult cerebrovasculature are unknown: can VEGF alter brain angiogenesis or mature cerebrovascular patterns? To examine these questions we exposed fetal, newborn, and adult rat cortical slice explants to graduated doses of recombinant VEGF. The effects of another known angiogenic factor, basic fibroblast growth factor (bFGF), were evaluated in a comparable manner. In addition, we infused VEGF via minipump into the adult cortex. Significant angiogenic effects were found in all VEGF experiments in a dose-responsive manner that were abolished by the addition of VEGF neutralizing antibody. Fetal and newborn explants had a highly complex network of branched vessels that immunoexpressed the flt-1 VEGF receptor, and flk-1 VEGF receptor expression was determined by reverse transcription–PCR. Adult explants had enlarged, dilated vessels that appeared to be an expansion of the existing network. All bFGF-treated explants had substantially fewer vascular profiles. VEGF infusions produced both a remarkable localized neovascularization and, unexpectedly, the expression of flt-1 on reactive astrocytes but not on endothelial cells. The preponderance of neovascularization in vitro and in vivo, however, lacked the blood–brain barrier (BBB) phenotype marker, GLUT-1, suggesting that in brain the angiogenic role of VEGF may differ from a potential BBB functional role, i.e., transport and permeability. VEGF may serve an important capacity in neovascularization or BBB alterations after brain injury. PMID:9618543

  4. Age, growth, and recruitment patterns of juvenile ladyfish (Elops sp) from the east coast of Florida (USA)

    PubMed Central

    2015-01-01

    Ladyfish (Elops sp) are a common and economically valuable coastal nearshore species found along coastal beaches, bays, and estuaries of the southeastern United States, and subtropical and tropical regions worldwide. Previously, ladyfish were a substantial bycatch in Florida’s commercial fisheries, but changes in regulations significantly reduced commercial landings. Today, ladyfish are still taken in commercial fisheries in Florida, but many are also taken by recreational anglers. Life-history information and research interest in ladyfish is almost non-existent, especially information on age and growth. Thus, the overarching purpose of this study was to expand our understanding of ladyfish age and growth characteristics. The specific objectives were to describe, for the first time, age, growth, and recruitment patterns of juvenile ladyfish from the east coast of Florida (USA). In the Indian River Lagoon (IRL), annual monthly length-frequency distributions were confounded because a few small individuals recruited throughout the year; monthly length-frequency data generally demonstrated a cyclical pattern. The smallest were collected in September and the largest in May. Post-hoc analysis showed no significant difference in length between August and May, or among the other months. In Volusia County (VC), annual monthly length-frequency distribution demonstrated growth generally occurred from late-winter and spring to summer. The smallest ladyfish were collected in February and the largest in August. On average, the absolute growth rate in the IRL was 36.3 mm in 60 days or 0.605 mm day−1. Cohort-specific daily growth rates, elevations, and coincidentals were similar among sampling years. Cohort-specific growth rates ranged from 1.807 in 1993 to 1.811 mm day−1 in 1994. Overall, growth was best (i.e., goodness of fit) described by exponential regression. On average, the absolute growth rate in VC was 28 mm in 150 days or 0.1866 mm day−1. Cohort-specific daily

  5. Patterns of Circulating Fibroblast Growth Factor 21 in Subjects with and without Type 2 Diabetes

    PubMed Central

    Ma, Xiaojing; Hao, Yaping; Lu, Wei; Li, Huating; Bao, Yuqian; Zhou, Jian; Jia, Weiping

    2015-01-01

    Background Fibroblast growth factor 21 (FGF21) exerts wide-range effects on carbohydrate and lipid metabolism. However, its perturbation in type 2 diabetes mellitus (T2DM) remains elusive. Besides, previous human studies in T2DM simply investigated fasting or stimulated levels of FGF21. The current study sought to evaluate the temporal changes of circulating FGF21 in subjects with and without T2DM. Methods Ten patients with T2DM and 16 normal controls (NC) were recruited. Participants were categorized as obese (BMI≥25 kg/m2) or lean (BMI<25 kg/m2). Blood samples were drawn every 30 min within 7 hours (8 a.m.-3 p.m.). Serum FGF21, blood glucose, insulin, free fatty acids (FFAs) and adiponectin were measured in all subjects. Results The peak levels of FGF21 were observed in the fasting state (8 a.m.) both in T2DM and NC groups (267.35 ±158.72 ng/L vs. 178.93±121.37 ng/L, P = 0.096). FGF21 AUC did not differ significantly between the two groups (T2DM: 949.4±471.47 ng/L; NC: 883.13±561.40 ng/L, P = 0.770). Obese subjects had higher FGF21 levels than lean ones in patients either with or without T2DM. The pattern of FFAs closely resembled that of FGF21. Correlation analysis showed that temporal levels of FGF21 were significantly related to FFAs (r = 0.749, P = 0.002),but not blood glucose, insulin or adiponectin (all P> 0.05). Conclusions These findings suggest that the pattern of circulating FGF21 does not differ significantly between T2DM and NC,although T2DM patients showed a trend toward higher fasting FGF21 than healthy subjects. The pattern of circulating FFAs is significantly associated with that of FGF21. PMID:26540514

  6. Gallium arsenide (GaAs) island growth under SiO(2) nanodisks patterned on GaAs substrates.

    PubMed

    Tjahjana, Liliana; Wang, Benzhong; Tanoto, Hendrix; Chua, Soo-Jin; Yoon, Soon Fatt

    2010-05-14

    We report a growth phenomenon where uniform gallium arsenide (GaAs) islands were found to grow underneath an ordered array of SiO(2) nanodisks on a GaAs(100) substrate. Each island eventually grows into a pyramidal shape resulting in the toppling of the supported SiO(2) nanodisk. This phenomenon occurred consistently for each nanodisk across a large patterned area of approximately 50 x 50 microm(2) (with nanodisks of 210 nm diameter and 280 nm spacing). The growth mechanism is attributed to a combination of 'catalytic' growth and facet formation.

  7. [Use of PubMed to improve evidence-based medicine in routine urological practice].

    PubMed

    Rink, M; Kluth, L A; Shariat, S F; Chun, F K; Fisch, M; Dahm, P

    2013-03-01

    Applying evidence-based medicine in daily clinical practice is the basis of patient-centered medicine and knowledge of accurate literature acquisition skills is necessary for informed clinical decision-making. PubMed is an easy accessible, free bibliographic database comprising over 21 million citations from the medical field, life-science journals and online books. The article summarizes the effective use of PubMed in routine urological clinical practice based on a common case scenario. This article explains the simple use of PubMed to obtain the best search results with the highest evidence. Accurate knowledge about the use of PubMed in routine clinical practice can improve evidence-based medicine and also patient treatment.

  8. Growth patterns of height and weight among three groups of Samoan preadolescents.

    PubMed

    Bindon, J R; Zansky, S M

    1986-01-01

    The Samoan population affords an excellent opportunity to study the influences of modernization and migration on growth. Moreover, since Samoan adults in some settings have very high rates of obesity, the childhood precursors to obesity can be studied among Samoans. This study reports the results of a survey of 786 Samoan children between 5.5 and 11.5 years of age living in traditional, modern or migrant situations. It was found that the children from Western Samoa (traditional) were significantly shorter, lighter and lighter for height than their counterparts in American Samoa (modern) and Hawaii (migrant). The major influence on height and weight appears to be modernization (Western versus American Samoa), with migration (American Samoa versus Hawaii) playing only a small incremental role (significant only for weight among boys). The influences of modernization are likely to be exerted through changes in diet and activity among the children. Modernization and migration are associated with obesity among Samoan adults, and this pattern also seems to be established in preadolescents.

  9. Process for selectively patterning epitaxial film growth on a semiconductor substrate

    DOEpatents

    Sheldon, Peter; Hayes, Russell E.

    1986-01-01

    A process is disclosed for selectively patterning epitaxial film growth on a semiconductor substrate. The process includes forming a masking member on the surface of the substrate, the masking member having at least two layers including a first layer disposed on the substrate and the second layer covering the first layer. A window is then opened in a selected portion of the second layer by removing that portion to expose the first layer thereunder. The first layer is then subjected to an etchant introduced through the window to dissolve a sufficient amount of the first layer to expose the substrate surface directly beneath the window, the first layer being adapted to preferentially dissolve at a substantially greater rate than the second layer so as to create an overhanging ledge portion with the second layer by undercutting the edges thereof adjacent to the window. The epitaxial film is then deposited on the exposed substrate surface directly beneath the window. Finally, an etchant is introduced through the window to dissolve the remainder of the first layer so as to lift-off the second layer and materials deposited thereon to fully expose the balance of the substrate surface.

  10. Copper removal ability by Streptomyces strains with dissimilar growth patterns and endowed with cupric reductase activity.

    PubMed

    Albarracín, Virginia Helena; Avila, Ana Lucía; Amoroso, María Julia; Abate, Carlos Mauricio

    2008-11-01

    Morphological, physiological and molecular characterization of three copper-resistant actinobacterial strains (AB2A, AB3 and AB5A) isolated from copper-polluted sediments of a drainage channel showed that they belonged to the genus Streptomyces. These characteristics plus their distinctive copper resistance phenotypes revealed considerable divergence among the isolates. Highly dissimilar growth patterns and copper removal efficiency were observed for the selected Streptomyces strains grown on minimal medium (MM) added with 0.5 mM of copper sulfate (MM(Cu)). Strain AB2A showed an early mechanism of copper uptake/retention (80% until day 3), followed by a drastic metal efflux process (days 5-7). In contrast, Streptomyces sp. AB3 and AB5A showed only copper retention phenotypes under the same culture conditions. Particularly, Streptomyces sp. AB5A showed a better efficiency in copper removal (94%), although a longer lag phase was observed for this microorganism grown for 7 days in MM(Cu). Cupric reductase activity was detected in both copper-adapted cells and nonadapted cells of all three strains but this activity was up to 100-fold higher in preadapted cells of Streptomyces sp. AB2A. To our knowledge, this is the first time that cupric reductase activity was demonstrated in Streptomyces strains.

  11. Control of patterning, growth, and differentiation by floral organ identity genes.

    PubMed

    Sablowski, Robert

    2015-02-01

    In spite of the different morphologies of sepals, petals, stamens, and carpels, all these floral organs are believed to be modified versions of a ground-state organ similar to the leaf. Modifications of the ground-state developmental programme are orchestrated by different combinations of MADS-domain transcription factors encoded by floral organ identity genes. In recent years, much has been revealed about the gene regulatory networks controlled by the floral organ identity genes and about the genetic pathways that control leaf development. This review examines how floral organ identity is connected with the control of morphogenesis and differentiation of shoot organs, focusing on the model species Arabidopsis thaliana. Direct links have emerged between floral organ identity genes and genes involved in abaxial-adaxial patterning, organ boundary formation, tissue growth, and cell differentiation. In parallel, predictive models have been developed to explain how the activity of regulatory genes can be coordinated by intercellular signalling and constrained by tissue mechanics. When combined, these advances provide a unique opportunity for revealing exactly how leaf-like organs have been 'metamorphosed' into floral organs during evolution and showing crucial regulatory points in the generation of plant form.

  12. Controlling the Growth Modes of Femtoliter Sessile Droplets Nucleating on Chemically Patterned Surfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Xuehua; Bao, Lei; Werbiuk, Zenon; Lohse, Detlef

    2016-11-01

    Femtoliter droplet arrays on immersed substrates are essential elements in a broad range of advanced droplet-based technologies, such as light manipulation, sensing, and high throughput diagnosis. Solvent exchange is a bottom-up approach for producing those droplets from a pulse of oil oversaturation when a good solvent of the droplet liquid is displaced by a poor solvent. The position and arrangement of the droplets are regulated by chemical micropatterns on the substrate. Here we show experimentally and theoretically that the growth modes of droplets confined in planar micropatterns on the surface can be manipulated through the laminar flow of the solvent exchange. The control parameters are the area size of the micropatterns and the flow rate, and the observables are the contact angle and the final droplet volume. For a given pattern size, the Peclet number of the flow determines whether the growing droplets switch from an initial constant contact angle mode to a subsequent constant contact radius mode. Good agreement is achieved between the experimental results and our theoretical model that describes the dependence of the final droplet size on Pe.

  13. Scaling up the shape: A novel growth pattern of gallium clusters

    SciTech Connect

    Kaware, Vaibhav; Joshi, Kavita E-mail: kavita.p.joshi@gmail.com

    2014-08-07

    Putative global minima for Ga{sub N}{sup +} clusters with size “N” ranging from 49 to 70 are found by employing the Kohn-Sham formulation of the density functional theory, and their evolution is described and discussed in detail. We have discovered a unique growth pattern in these clusters, all of which are hollow core-shell structures. They evolve with size from one spherical core-shell to the next spherical core-shell structure mediated by prolate geometries, with an increase in overall diameter of the core, as well as the shell, without putting on new layers of atoms. We also present a complete picture of bonding in gallium clusters by critically analyzing the molecular orbitals, the electron localization function, and Bader charges. Bonding in these clusters is a mixture of metallic and covalent type that leans towards covalency, accompanied by marginal charge transfer from the surface to the core. Most molecular orbitals of Ga clusters are non-jellium type. Covalency of bonding is supported by a wide localization window of electron localization function, and joining of its basins along the bonds.

  14. Process for selectively patterning epitaxial film growth on a semiconductor substrate

    DOEpatents

    Sheldon, P.; Hayes, R.E.

    1984-12-04

    Disclosed is a process for selectively patterning epitaxial film growth on a semiconductor substrate. The process includes forming a masking member on the surface of the substrate, the masking member having at least two layers including a first layer disposed on the substrate and the second layer covering the first layer. A window is then opened in a selected portion of the second layer by removing that portion to expose the first layer thereunder. The first layer is then subjected to an etchant introduced through the window to dissolve the first layer a sufficient amount to expose the substrate surface directly beneath the window, the first layer being adapted to preferentially dissolve at a substantially greater rate than the second layer so as to create an overhanging ledge portion with the second layer by undercutting the edges thereof adjacent the window. The epitaxial film is then deposited on the exposed substrate surface directly beneath the window. Finally, an etchant is introduced through the window to dissolve the remainder of the first layer so as to lift-off the second layer and materials deposited thereon to fully expose the balance of the substrate surface.

  15. Centimeter scale pattern growth of graphene films for stretchable transparent electrodes

    NASA Astrophysics Data System (ADS)

    Hong, Byung Hee

    2009-03-01

    Large scale pattern growth of graphene is one of the most awaiting problems to be solved in order to bring this material for device application. Recently, macroscopic scale graphene films have been prepared by two-dimensional assembly of graphene sheets chemically derived from graphite crystals and graphene oxides. However, the sheet resistance of these films is found to be much larger than theoretically expected values. Here, we report the direct synthesis of centimeter-scale graphene films using chemical vapor deposition (CVD) on thin Ni layers, where the overall structures are connected by lateral electric connections. As a result, the transferred graphene films show very low sheet resistance with excellent optical transparency. At low temperatures, the single layers transferred on SiO2 substrates show high electron mobility with the signature of quantum Hall effect, implying that the quality of CVD-grown graphene is as high as mechanically cleaved graphenes. Employing these outstanding mechanical properties of graphenes, we also demonstrate the macroscopic usage of the highly conducting and transparent electrodes for flexible/stretchable/foldable electronics.

  16. Expression Pattern of Early Growth Response Gene 1 during Olive Flounder (Paralichthys olivaceus) Embryonic Development

    PubMed Central

    Yang, Hyun; Lee, Jeong-Ho; Noh, Jae Koo; Kim, Hyun Chul; Park, Choul-Ji; Park, Jong-Won; Kim, Kyung-Kil

    2014-01-01

    The early growth response protein 1 (Egr-1) is a widely reported zinc finger protein and a well known transcription factor encoded by the Egr-1 gene, which plays key roles in many aspects of vertebrate embryogenesis and in adult vertebrates. The Egr-1 expression is important in the formation of the gill vascular system in flounders, which develops during the post-hatching phase and is essential for survival during the juvenile period. However, the complete details of Egr-1 expression during embryo development in olive flounder are not available. We assessed the expression patterns of Egr-1 during the early development of olive flounders by using reverse transcription polymerase chain reaction (RT-PCR) analysis. Microscopic observations showed that gill filament formation corresponded with the Egr-1 expression. Thus, we showed that Egr-1 plays a vital role in angiogenesis in the gill filaments during embryogenesis. Further, Egr-1 expression was found to be strong at 5 days after hatching (DAH), in the development of the gill vascular system, and this strong expression level was maintained throughout all the development stages. Our findings have important implications with respect to the biological role of Egr-1 and evolution of the first respiratory blood vessels in the gills of olive flounder. Further studies are required to elucidate the Egr-1-mediated stress response and to decipher the functional role of Egr-1 in developmental stages. PMID:25949193

  17. GOClonto: an ontological clustering approach for conceptualizing PubMed abstracts.

    PubMed

    Zheng, Hai-Tao; Borchert, Charles; Kim, Hong-Gee

    2010-02-01

    Concurrent with progress in biomedical sciences, an overwhelming of textual knowledge is accumulating in the biomedical literature. PubMed is the most comprehensive database collecting and managing biomedical literature. To help researchers easily understand collections of PubMed abstracts, numerous clustering methods have been proposed to group similar abstracts based on their shared features. However, most of these methods do not explore the semantic relationships among groupings of documents, which could help better illuminate the groupings of PubMed abstracts. To address this issue, we proposed an ontological clustering method called GOClonto for conceptualizing PubMed abstracts. GOClonto uses latent semantic analysis (LSA) and gene ontology (GO) to identify key gene-related concepts and their relationships as well as allocate PubMed abstracts based on these key gene-related concepts. Based on two PubMed abstract collections, the experimental results show that GOClonto is able to identify key gene-related concepts and outperforms the STC (suffix tree clustering) algorithm, the Lingo algorithm, the Fuzzy Ants algorithm, and the clustering based TRS (tolerance rough set) algorithm. Moreover, the two ontologies generated by GOClonto show significant informative conceptual structures.

  18. Tracking Australian health and medical research expenditure with a PubMed bibliometric method.

    PubMed

    Mendis, Kumara; Bailey, Jannine; McLean, Rick

    2015-06-01

    To assess Australian health and medical research (HMR) investment returns by measuring the trends in HMR expenditure and PubMed publications by Australian authors. Bibliometric analysis collating Australian HMR expenditure reported by the Australian Institute of Health and Welfare and Australian HMR publications indexed in PubMed. Similar methods were applied to data from the United Kingdom and New Zealand. From financial year 2000/01 through 2011/12, HMR investment increased by 232% from $1.49 to $4.94 billion (current prices adjusted for inflation), while PubMed publications increased by 123% from 10,696 to 23,818. The average HMR investment required for a single PubMed publication rose by 49% from $139,304 in 2000/01 to $207,364 in 2011/12. Quality analyses showed an increase in systematic reviews, cohort studies and clinical trials, and a decrease in publications in PubMed's core clinical journal collection. Comparisons with New Zealand and the United Kingdom showed that Australia has had the greatest overall percentage increase in gross publication numbers and publications per capita. Our analyses confirm that increased HMR expenditure is associated with an increase in HMR publications in PubMed. Tracking HMR investment outcomes using this method could be useful for future policy and funding decisions at a federal and specific institution level. © 2015 Public Health Association of Australia.

  19. Patterns of growth dominance in thinned yellow-poplar stands in the southern Appalachian Mountains, USA

    Treesearch

    Tara L. Keyser

    2012-01-01

    Growth dominance provides a quantitative description of the relative contribution of individual trees to stand growth. Positive dominance occurs when the largest individuals account for a greater proportion of growth period increment than total biomass. Conversely, negative dominance occurs when the smallest trees account for a greater proportion of the growth period...

  20. Patterns of mortality in an old-growth mixed-conifer forest of the Southern Sierra Nevada, California

    Treesearch

    Thomas F. Smith; David M. Rizzo; Malcolm North

    2005-01-01

    Mortality patterns in an old-growth, mixed-conifer forest, in the absence of wildfire, were investigated at the Teakettle Experimental Forest from 2000 to 2002. We tested the hypothesis that after a century of fire suppression, pathogen- and insect-associated mortality (between episodic droughts) would be significantly greater on ingrowth trees (i.e., smaller-diameter...

  1. Self-Esteem Trajectories among Ethnic Minority Adolescents: A Growth Curve Analysis of the Patterns and Predictors of Change

    ERIC Educational Resources Information Center

    Greene, Melissa L.; Way, Niobe

    2005-01-01

    The current study presents a growth curve analysis of self-esteem among Black, Latino, and Asian American high school students. A series of hierarchical linear models were used to examine patterns and predictors of change in self-esteem over time. Results revealed an average increase in self-esteem with age. Although boys and girls experienced…

  2. Self-Esteem Trajectories among Ethnic Minority Adolescents: A Growth Curve Analysis of the Patterns and Predictors of Change

    ERIC Educational Resources Information Center

    Greene, Melissa L.; Way, Niobe

    2005-01-01

    The current study presents a growth curve analysis of self-esteem among Black, Latino, and Asian American high school students. A series of hierarchical linear models were used to examine patterns and predictors of change in self-esteem over time. Results revealed an average increase in self-esteem with age. Although boys and girls experienced…

  3. Spiral and target patterns in bivalve nacre manifest a natural excitable medium from layer growth of a biological liquid crystal.

    PubMed

    Cartwright, Julyan H E; Checa, Antonio G; Escribano, Bruno; Sainz-Díaz, C Ignacio

    2009-06-30

    Nacre is an exquisitely structured biocomposite of the calcium carbonate mineral aragonite with small amounts of proteins and the polysaccharide chitin. For many years, it has been the subject of research, not just because of its beauty, but also to discover how nature can produce such a superior product with excellent mechanical properties from such relatively weak raw materials. Four decades ago, Wada [Wada K (1966) Spiral growth of nacre. Nature 211:1427] proposed that the spiral patterns in nacre could be explained by using the theory Frank [Frank F (1949) The influence of dislocations on crystal growth. Discuss Faraday Soc 5:48-54] had put forward of the growth of crystals by means of screw dislocations. Frank's mechanism of crystal growth has been amply confirmed by experimental observations of screw dislocations in crystals, but it is a growth mechanism for a single crystal, with growth fronts of molecules. However, the growth fronts composed of many tablets of crystalline aragonite visible in micrographs of nacre are not a molecular-scale but a mesoscale phenomenon, so it has not been evident how the Frank mechanism might be of relevance. Here, we demonstrate that nacre growth is organized around a liquid-crystal core of chitin crystallites, a skeleton that the other components of nacre subsequently flesh out in a process of hierarchical self-assembly. We establish that spiral and target patterns can arise in a liquid crystal formed layer by layer through the Burton-Cabrera-Frank [Burton W, Cabrera N, Frank F (1951) The growth of crystals and the equilibrium structure of their surfaces. Philos Trans R Soc London Ser A 243:299-358] dynamics, and furthermore that this layer growth mechanism is an instance of an important class of physical systems termed excitable media. Artificial liquid crystals grown in this way may have many technological applications.

  4. Spiral and target patterns in bivalve nacre manifest a natural excitable medium from layer growth of a biological liquid crystal

    PubMed Central

    Cartwright, Julyan H. E.; Checa, Antonio G.; Escribano, Bruno; Sainz-Díaz, C. Ignacio

    2009-01-01

    Nacre is an exquisitely structured biocomposite of the calcium carbonate mineral aragonite with small amounts of proteins and the polysaccharide chitin. For many years, it has been the subject of research, not just because of its beauty, but also to discover how nature can produce such a superior product with excellent mechanical properties from such relatively weak raw materials. Four decades ago, Wada [Wada K (1966) Spiral growth of nacre. Nature 211:1427] proposed that the spiral patterns in nacre could be explained by using the theory Frank [Frank F (1949) The influence of dislocations on crystal growth. Discuss Faraday Soc 5:48–54] had put forward of the growth of crystals by means of screw dislocations. Frank's mechanism of crystal growth has been amply confirmed by experimental observations of screw dislocations in crystals, but it is a growth mechanism for a single crystal, with growth fronts of molecules. However, the growth fronts composed of many tablets of crystalline aragonite visible in micrographs of nacre are not a molecular-scale but a mesoscale phenomenon, so it has not been evident how the Frank mechanism might be of relevance. Here, we demonstrate that nacre growth is organized around a liquid-crystal core of chitin crystallites, a skeleton that the other components of nacre subsequently flesh out in a process of hierarchical self-assembly. We establish that spiral and target patterns can arise in a liquid crystal formed layer by layer through the Burton–Cabrera–Frank [Burton W, Cabrera N, Frank F (1951) The growth of crystals and the equilibrium structure of their surfaces. Philos Trans R Soc London Ser A 243:299–358] dynamics, and furthermore that this layer growth mechanism is an instance of an important class of physical systems termed excitable media. Artificial liquid crystals grown in this way may have many technological applications. PMID:19528636

  5. Water temperature and fish growth: otoliths predict growth patterns of a marine fish in a changing climate.

    PubMed

    Rountrey, Adam N; Coulson, Peter G; Meeuwig, Jessica J; Meekan, Mark

    2014-08-01

    Ecological modeling shows that even small, gradual changes in body size in a fish population can have large effects on natural mortality, biomass, and catch. However, efforts to model the impact of climate change on fish growth have been hampered by a lack of long-term (multidecadal) data needed to understand the effects of temperature on growth rates in natural environments. We used a combination of dendrochronology techniques and additive mixed-effects modeling to examine the sensitivity of growth in a long-lived (up to 70 years), endemic marine fish, the western blue groper (Achoerodus gouldii), to changes in water temperature. A multi-decadal biochronology (1952-2003) of growth was constructed from the otoliths of 56 fish collected off the southwestern coast of Western Australia, and we tested for correlations between the mean index chronology and a range of potential environmental drivers. The chronology was significantly correlated with sea surface temperature in the region, but common variance among individuals was low. This suggests that this species has been relatively insensitive to past variations in climate. Growth increment and age data were also used in an additive mixed model to predict otolith growth and body size later this century. Although growth was relatively insensitive to changes in temperature, the model results suggested that a fish aged 20 in 2099 would have an otolith about 10% larger and a body size about 5% larger than a fish aged 20 in 1977. Our study shows that species or populations regarded as relatively insensitive to climate change could still undergo significant changes in growth rate and body size that are likely to have important effects on the productivity and yield of fisheries. © 2014 John Wiley & Sons Ltd.

  6. Percutaneous adhesiolysis procedures in the medicare population: analysis of utilization and growth patterns from 2000 to 2011.

    PubMed

    Manchikanti, Laxmaiah; Helm Ii, Standiford; Pampati, Vidyasagar; Racz, Gabor B

    2014-01-01

    Multiple reviews have shown that interventional techniques for chronic pain have increased dramatically over the years. Of these interventional techniques, both sacroiliac joint injections and facet joint interventions showed explosive growth, followed by epidural procedures. Percutaneous adhesiolysis procedures have not been assessed for their utilization patterns separately from epidural injections. An analysis of the utilization patterns of percutaneous adhesiolysis procedures in managing chronic low back pain in the Medicare population from 2000 to 2011. To assess the utilization and growth patterns of percutaneous adhesiolysis in managing chronic low back pain. The study was performed utilizing the Centers for Medicare and Medicaid Services (CMS) Physician Supplier Procedure Summary Master of Fee-For-Service (FFS) Data from 2000 to 2011. Percutaneous adhesiolysis procedures increased 47% with an annual growth rate of 3.6% in the FFS Medicare population from 2000 to 2011. These growth rates are significantly lower than the growth rates for sacroiliac joint injections (331%), facet joint interventions (308%), and epidural injections (130%), but substantially lower than lumbar transforaminal injections (665%) and lumbar facet joint neurolysis (544%). Study limitations include lack of inclusion of Medicare Advantage patients. In addition, the statewide data is based on claims which may include the contiguous or other states. Percutaneous adhesiolysis utilization increased moderately in Medicare beneficiaries from 2000 to 2011. Overall, there was an increase of 47% in the utilization of adhesiolysis procedures per 100,000 Medicare beneficiaries, with an annual geometric average increase of 3.6%.

  7. Seedless Pattern Growth of Quasi-Aligned ZnO Nanorod Arrays on Cover Glass Substrates in Solution

    PubMed Central

    2010-01-01

    A hybrid technique for the selective growth of ZnO nanorod arrays on wanted areas of thin cover glass substrates was developed without the use of seed layer of ZnO. This method utilizes electron-beam lithography for pattern transfer on seedless substrate, followed by solution method for the bottom-up growth of ZnO nanorod arrays on the patterned substrates. The arrays of highly crystalline ZnO nanorods having diameter of 60 ± 10 nm and length of 750 ± 50 nm were selectively grown on different shape patterns and exhibited a remarkable uniformity in terms of diameter, length, and density. The room temperature cathodluminescence measurements showed a strong ultraviolet emission at 381 nm and broad visible emission at 585–610 nm were observed in the spectrum. PMID:20672029

  8. Scaling in the growth of geographically subdivided populations: invariant patterns from a continent-wide biological survey

    NASA Astrophysics Data System (ADS)

    Keitt, Timothy H.

    2003-03-01

    We consider statistical patterns of variation in growth rates for over 400 species of breeding birds across North America surveyed from 1966 to 1998. We report two results. First, the standard deviation of population growth rates decays as a power-law function of total population size with an exponent β = 0.360.02. Second, the number of subpopulations, measured as the number of survey locations with non-zero counts, scales to the 3/4-power of total number of birds counted in a given species. We show how these patterns may be related, and discuss a simple stochastic growth model for a geographically subdivided population that formalizes the relationship. We also examine reasons that may explain why some species deviate from these scaling-laws.

  9. Scaling in the growth of geographically subdivided populations: invariant patterns from a continent-wide biological survey.

    PubMed Central

    Keitt, Timothy H; Amaral, Luis A N; Buldyrev, Sergey V; Stanley, H Eugene

    2002-01-01

    We consider statistical patterns of variation in growth rates for over 400 species of breeding birds across North America surveyed from 1966 to 1998. We report two results. First, the standard deviation of population growth rates decays as a power-law function of total population size with an exponent beta = 0.36 +/- 0.02. Second, the number of subpopulations, measured as the number of survey locations with non-zero counts, scales to the 3/4 power of total number of birds counted in a given species. We show how these patterns may be related, and discuss a simple stochastic growth model for a geographically subdivided population that formalizes the relationship. We also examine reasons that may explain why some species deviate from these scaling laws. PMID:12079524

  10. Net improvement of correct answers to therapy questions after pubmed searches: pre/post comparison.

    PubMed

    McKibbon, Kathleen Ann; Lokker, Cynthia; Keepanasseril, Arun; Wilczynski, Nancy L; Haynes, R Brian

    2013-11-08

    Clinicians search PubMed for answers to clinical questions although it is time consuming and not always successful. To determine if PubMed used with its Clinical Queries feature to filter results based on study quality would improve search success (more correct answers to clinical questions related to therapy). We invited 528 primary care physicians to participate, 143 (27.1%) consented, and 111 (21.0% of the total and 77.6% of those who consented) completed the study. Participants answered 14 yes/no therapy questions and were given 4 of these (2 originally answered correctly and 2 originally answered incorrectly) to search using either the PubMed main screen or PubMed Clinical Queries narrow therapy filter via a purpose-built system with identical search screens. Participants also picked 3 of the first 20 retrieved citations that best addressed each question. They were then asked to re-answer the original 14 questions. We found no statistically significant differences in the rates of correct or incorrect answers using the PubMed main screen or PubMed Clinical Queries. The rate of correct answers increased from 50.0% to 61.4% (95% CI 55.0%-67.8%) for the PubMed main screen searches and from 50.0% to 59.1% (95% CI 52.6%-65.6%) for Clinical Queries searches. These net absolute increases of 11.4% and 9.1%, respectively, included previously correct answers changing to incorrect at a rate of 9.5% (95% CI 5.6%-13.4%) for PubMed main screen searches and 9.1% (95% CI 5.3%-12.9%) for Clinical Queries searches, combined with increases in the rate of being correct of 20.5% (95% CI 15.2%-25.8%) for PubMed main screen searches and 17.7% (95% CI 12.7%-22.7%) for Clinical Queries searches. PubMed can assist clinicians answering clinical questions with an approximately 10% absolute rate of improvement in correct answers. This small increase includes more correct answers partially offset by a decrease in previously correct answers.

  11. Growth patterns in early childhood: Better trajectories in Afro-Ecuadorians independent of sex and socioeconomic factors.

    PubMed

    Matos, Sheila Maria Alvim; Amorim, Leila D; Campos, Ana Clara P; Barreto, Mauricio L; Rodrigues, Laura C; Morejón, Yadira A; Chico, Martha E; Cooper, Philip J

    2017-08-01

    The first years of life are the most dynamic period for childhood growth. There are limited data available on growth patterns of infants and children living in rural Latin America. The aim of this study was to describe the growth patterns from birth to 5years in children living in a rural District of tropical coastal Ecuador using data from a birth cohort of 2404 neonates. We hypothesize that there would be growth differences according to ethnicity and sex. Evaluations were conducted at birth or until 2weeks of age and at 7, 13, 24, 36 and 60months during clinic and home visits. Individual growth trajectories for weight-for-age, height-for-age and weight/height-for-age Z-scores were estimated using multilevel models. Girls were lighter and shorter than boys at birth. However, Afro-Ecuadorian children (versus mestizo or indigenous) were longer/taller and heavier throughout the first 5years of life and had greater mean trajectories for HAZ and WAZ independent of sex and socioeconomic factors. Our data indicate that ethnicity is a determinant of growth trajectories during the first 5years of life independent of socioeconomic factors in a birth cohort conducted in a rural region of Latin America. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Highly patterned growth of SnO2 nanowires using a sub-atmospheric vapor-liquid-solid deposition

    NASA Astrophysics Data System (ADS)

    Akbari, M.; Mohajerzadeh, S.

    2017-08-01

    We report the realization of tin-oxide nanowires on patterned structures using a vapor-liquid-solid (VLS) process. While gold acts as the catalyst for the growth of wires, a tin-oxide containing sol-gel solution is spin coated on silicon substrate to act as the source for SnO vapor. The growth of tin-oxide nano-structures occurs mostly at the vicinity of the pre-deposited solution. By patterning the gold as the catalyst material, one is able to observe the growth at desired places. The growth of nanowires is highly dense within 100 µm away from such in situ source and their length is of the order of 5 µm. By further distancing from the source, the growth becomes more limited and nanowires become shorter and more sparsely distributed. The growth of nanowires has been studied using scanning and transmission electron microscopy tools while their composition has been investigated using XRD and EDS analyses. As a novel application, we have employed the grown nanowires as electron detection elements to measure the emitted electrons from electron sources. This configuration can be further used as electron detectors for scanning electron microscopes.

  13. Selecting a linear mixed model for longitudinal data: repeated measures analysis of variance, covariance pattern model, and growth curve approaches.

    PubMed

    Liu, Siwei; Rovine, Michael J; Molenaar, Peter C M

    2012-03-01

    With increasing popularity, growth curve modeling is more and more often considered as the 1st choice for analyzing longitudinal data. Although the growth curve approach is often a good choice, other modeling strategies may more directly answer questions of interest. It is common to see researchers fit growth curve models without considering alterative modeling strategies. In this article we compare 3 approaches for analyzing longitudinal data: repeated measures analysis of variance, covariance pattern models, and growth curve models. As all are members of the general linear mixed model family, they represent somewhat different assumptions about the way individuals change. These assumptions result in different patterns of covariation among the residuals around the fixed effects. In this article, we first indicate the kinds of data that are appropriately modeled by each and use real data examples to demonstrate possible problems associated with the blanket selection of the growth curve model. We then present a simulation that indicates the utility of Akaike information criterion and Bayesian information criterion in the selection of a proper residual covariance structure. The results cast doubt on the popular practice of automatically using growth curve modeling for longitudinal data without comparing the fit of different models. Finally, we provide some practical advice for assessing mean changes in the presence of correlated data.

  14. Improving accuracy for identifying related PubMed queries by an integrated approach.

    PubMed

    Lu, Zhiyong; Wilbur, W John

    2009-10-01

    PubMed is the most widely used tool for searching biomedical literature online. As with many other online search tools, a user often types a series of multiple related queries before retrieving satisfactory results to fulfill a single information need. Meanwhile, it is also a common phenomenon to see a user type queries on unrelated topics in a single session. In order to study PubMed users' search strategies, it is necessary to be able to automatically separate unrelated queries and group together related queries. Here, we report a novel approach combining both lexical and contextual analyses for segmenting PubMed query sessions and identifying related queries and compare its performance with the previous approach based solely on concept mapping. We experimented with our integrated approach on sample data consisting of 1539 pairs of consecutive user queries in 351 user sessions. The prediction results of 1396 pairs agreed with the gold-standard annotations, achieving an overall accuracy of 90.7%. This demonstrates that our approach is significantly better than the previously published method. By applying this approach to a one day query log of PubMed, we found that a significant proportion of information needs involved more than one PubMed query, and that most of the consecutive queries for the same information need are lexically related. Finally, the proposed PubMed distance is shown to be an accurate and meaningful measure for determining the contextual similarity between biological terms. The integrated approach can play a critical role in handling real-world PubMed query log data as is demonstrated in our experiments.

  15. Improving accuracy for identifying related PubMed queries by an integrated approach

    PubMed Central

    Lu, Zhiyong; Wilbur, W. John

    2009-01-01

    PubMed is the most widely used tool for searching biomedical literature online. As with many other online search tools, a user often types a series of multiple related queries before retrieving satisfactory results to fulfill a single information need. Meanwhile, it is also a common phenomenon to see a user type queries on unrelated topics in a single session. In order to study PubMed users’ search strategies, it is necessary to be able to automatically separate unrelated queries and group together related queries. Here, we report a novel approach combining both lexical and contextual analyses for segmenting PubMed query sessions and identifying related queries and compare its performance with the previous approach based solely on concept mapping. We experimented with our integrated approach on sample data consisting of 1,539 pairs of consecutive user queries in 351 user sessions. The prediction results of 1,396 pairs agreed with the gold-standard annotations, achieving an overall accuracy of 90.7%. This demonstrates that our approach is significantly better than the previously published method. By applying this approach to a one day query log of PubMed, we found that a significant proportion of information needs involved more than one PubMed query, and that most of the consecutive queries for the same information need are lexically related. Finally, the proposed PubMed distance is shown to be an accurate and meaningful measure for determining the contextual similarity between biological terms. The integrated approach can play a critical role in handling real-world PubMed query log data as is demonstrated in our experiments. PMID:19162232

  16. Hybridization between Yellowstone cutthroat trout and rainbow trout alters the expression of muscle growth-related genes and their relationships with growth patterns

    USGS Publications Warehouse

    Ostberg, Carl O.; Chase, Dorothy M.; Hauser, Lorenz

    2015-01-01

    Hybridization creates novel gene combinations that may generate important evolutionary novelty, but may also reduce existing adaptation by interrupting inherent biological processes, such as genotype-environment interactions. Hybridization often causes substantial change in patterns of gene expression, which, in turn, may cause phenotypic change. Rainbow trout (Oncorhynchus mykiss) and cutthroat trout (O. clarkii) produce viable hybrids in the wild, and introgressive hybridization with introduced rainbow trout is a major conservation concern for native cutthroat trout. The two species differ in body shape, which is likely an evolutionary adaptation to their native environments, and their hybrids tend to show intermediate morphology. The characterization of gene expression patterns may provide insights on the genetic basis of hybrid and parental morphologies, as well as on the ecological performance of hybrids in the wild. Here, we evaluated the expression of eight growth-related genes (MSTN-1a, MSTN-1b, MyoD1a, MyoD1b, MRF-4, IGF-1, IGF-2, and CAST-L) and the relationship of these genes with growth traits (length, weight, and condition factor) in six line crosses: both parental species, both reciprocal F1 hybrids, and both first-generation backcrosses (F1 x rainbow trout and F1 x cutthroat trout). Four of these genes were differentially expressed among rainbow, cutthroat, and their hybrids. Transcript abundance was significantly correlated with growth traits across the parent species, but not across hybrids. Our findings suggest that rainbow and cutthroat trout exhibit differences in muscle growth regulation, that transcriptional networks may be modified by hybridization, and that hybridization disrupts intrinsic relationships between gene expression and growth patterns that may be functionally important for phenotypic adaptations.

  17. Hybridization between Yellowstone Cutthroat Trout and Rainbow Trout Alters the Expression of Muscle Growth-Related Genes and Their Relationships with Growth Patterns.

    PubMed

    Ostberg, Carl O; Chase, Dorothy M; Hauser, Lorenz

    2015-01-01

    Hybridization creates novel gene combinations that may generate important evolutionary novelty, but may also reduce existing adaptation by interrupting inherent biological processes, such as genotype-environment interactions. Hybridization often causes substantial change in patterns of gene expression, which, in turn, may cause phenotypic change. Rainbow trout (Oncorhynchus mykiss) and cutthroat trout (O. clarkii) produce viable hybrids in the wild, and introgressive hybridization with introduced rainbow trout is a major conservation concern for native cutthroat trout. The two species differ in body shape, which is likely an evolutionary adaptation to their native environments, and their hybrids tend to show intermediate morphology. The characterization of gene expression patterns may provide insights on the genetic basis of hybrid and parental morphologies, as well as on the ecological performance of hybrids in the wild. Here, we evaluated the expression of eight growth-related genes (MSTN-1a, MSTN-1b, MyoD1a, MyoD1b, MRF-4, IGF-1, IGF-2, and CAST-L) and the relationship of these genes with growth traits (length, weight, and condition factor) in six line crosses: both parental species, both reciprocal F1 hybrids, and both first-generation backcrosses (F1 x rainbow trout and F1 x cutthroat trout). Four of these genes were differentially expressed among rainbow, cutthroat, and their hybrids. Transcript abundance was significantly correlated with growth traits across the parent species, but not across hybrids. Our findings suggest that rainbow and cutthroat trout exhibit differences in muscle growth regulation, that transcriptional networks may be modified by hybridization, and that hybridization disrupts intrinsic relationships between gene expression and growth patterns that may be functionally important for phenotypic adaptations.

  18. Hybridization between Yellowstone Cutthroat Trout and Rainbow Trout Alter