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Sample records for pubmed growth patterns

  1. 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

  2. Pattern, growth, and control.

    PubMed

    Lander, Arthur D

    2011-03-18

    Systems biology seeks not only to discover the machinery of life but to understand how such machinery is used for control, i.e., for regulation that achieves or maintains a desired, useful end. This sort of goal-directed, engineering-centered approach also has deep historical roots in developmental biology. Not surprisingly, developmental biology is currently enjoying an influx of ideas and methods from systems biology. This Review highlights current efforts to elucidate design principles underlying the engineering objectives of robustness, precision, and scaling as they relate to the developmental control of growth and pattern formation. Examples from vertebrate and invertebrate development are used to illustrate general lessons, 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 absence of "free lunch." By illuminating such principles, systems biology is helping to create a functional framework within which to make sense of the mechanistic complexity of organismal development. PMID:21414486

  3. 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).

  4. Patterned Growth in Extreme Environments

    NASA Astrophysics Data System (ADS)

    Curnutt, J.; Gomez, E.; Schubert, K. E.

    2009-12-01

    In this paper, cellular automata are used to model patterned growth of organisms in extreme environments. A brief introduction to cellular automaton modeling is given to assist the reader. Patterned growth of soil surface cyanobacteria and biovermiculation microbial mats in sulfuric acid caves are modeled and simulations conducted. Simulations are compared with actual systems, and future directions are discussed.

  5. Growth patterns of adolescents in Bahrain.

    PubMed

    Mater, A M; Alekri, S A; Mahdi, A R; Musaiger, A O

    1990-10-01

    Weight and height of adolescents in Bahrain (15.5-19.5 years) was measured to evaluate their growth patterns. A cross-sectional survey was done on 825 students that represented 5% of total secondary students. The results showed that median height and weight of Bahraini adolescents were below the 50th percentiles of the Western standard. However, when compared with earlier surveys in Bahrain, the growth pattern has improved. This is because of improvement in health and in the environment.

  6. 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)…

  7. Parabolic growth patterns in 96-well plate cell growth experiments.

    PubMed

    Faessel, H M; Levasseur, L M; Slocum, H K; Greco, W R

    1999-05-01

    In preparing for the routine use of the ubiquitous in vitro cell growth inhibition assay for the study of anticancer agents, we characterized the statistical properties of the assay and found some surprising results. Parabolic well-to-well cell growth patterns were discovered, which could profoundly affect the results of routine growth inhibition studies of anticancer and other agents. Four human ovarian cell lines, A2780/WT, A2780/DX5, A2780/DX5B, and A121, and one human ileocecal adenocarcinoma cell line, HCT-8, were seeded into plastic 96-well plates with a 12-channel pipette, without drugs, and grown from 1-5 d. The wells were washed with a plate washer, cells stained with sulforhodamine B (SRB), and dye absorbance measured with a plate reader. Variance models were fit to the data from replicates to determine the nature of the heteroscedastic error structure. Exponential growth models were fit to data to estimate doubling times for each cell line. Polynomial models were fit to data from 10-plate stacks of 96-well plates to explore nonuniformity of cell growth in wells in different regions of the stacks. Each separate step in the assay was examined for precision, patterns, and underlying causes of variation. Differential evaporation of water from wells is likely a major, but not exclusive, contributor to the systematic well-to-well cell growth patterns. Because the fundamental underlying causes of the parabolic growth patterns were not conclusively found, a randomization step for the growth assay was developed.

  8. 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

  9. 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

  10. 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…

  11. 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.

  12. 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.

  13. PubMed Assistant: a biologist-friendly interface for enhanced PubMed search.

    PubMed

    Ding, Jing; Hughes, Laron M; Berleant, Daniel; Fulmer, Andy W; Wurtele, Eve Syrkin

    2006-02-01

    MEDLINE is one of the most important bibliographical information sources for biologists and medical workers. Its PubMed interface supports Boolean queries, which are potentially expressive and exact. However, PubMed is also designed to support simplicity of use at the expense of query expressiveness and exactness. Many PubMed users have never tried explicit Boolean queries. We developed a Java program, PubMed Assistant, to make literature access easier in several ways. PubMed Assistant provides an interface that efficiently displays information about the citations and includes useful functions such as keyword highlighting, export to citation managers, clickable links to Google Scholar and others that are lacking in PubMed.

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. Secretory pattern of canine growth hormone

    SciTech Connect

    French, M.B.; Vaitkus, P.; Cukerman, E.; Sirek, A.; Sirek, O.V.

    1987-02-01

    The aim of this paper was to define the secretory pattern of growth hormone (GH) under basal conditions in fasted, conscious, male dogs accustomed to handling. Blood samples were withdrawn from a cephalic vein at 15-min intervals. In this way, any ultradian rhythms, if present, could be detected within the frequency range of 0.042-2 cycles/h. In addition, samples were drawn at either 1- or 2.5-min intervals for 2.5 or 5 h to determine whether frequency components greater than 2 cycles/h were present. GH was measured by radioimmunoassay and the raw data were submitted to time series analysis employing power spectral estimation by means of fast Fourier transformation techniques. Peak plasma levels were up to 12 times higher than the baseline concentration of approx. 1 ng/ml. Spectral analysis revealed an endogenous frequency of 0.22 cycles/h, i.e., a periodicity of 4.5 h/cycle. The results indicate that under basal conditions the secretory bursts of canine GH are limited to one peak every 4.5 h.

  19. 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…

  20. 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.

  1. 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. PMID:11473315

  2. 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.

  3. 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

  4. Emergent patterns of growth controlled by multicellular form and mechanics

    PubMed Central

    Nelson, Celeste M.; Jean, Ronald P.; Tan, John L.; Liu, Wendy F.; Sniadecki, Nathan J.; Spector, Alexander A.; Chen, Christopher S.

    2005-01-01

    Spatial patterns of cellular growth generate mechanical stresses that help to push, fold, expand, and deform tissues into their specific forms. Genetic factors are thought to specify patterns of growth and other behaviors to drive morphogenesis. Here, we show that tissue form itself can feed back to regulate patterns of proliferation. Using microfabrication to control the organization of sheets of cells, we demonstrated the emergence of stable patterns of proliferative foci. Regions of concentrated growth corresponded to regions of high tractional stress generated within the sheet, as predicted by a finite-element model of multicellular mechanics and measured directly by using a micromechanical force sensor array. Inhibiting actomyosin-based tension or cadherin-mediated connections between cells disrupted the spatial pattern of proliferation. These findings demonstrate the existence of patterns of mechanical forces that originate from the contraction of cells, emerge from their multicellular organization, and result in patterns of growth. Thus, tissue form is not only a consequence but also an active regulator of tissue growth. PMID:16049098

  5. 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

  6. The relationship between growth and pattern formation.

    PubMed

    Bryant, Susan V; Gardiner, David M

    2016-04-01

    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

  7. Wrinkling pattern evolution of cylindrical biological tissues with differential growth

    NASA Astrophysics Data System (ADS)

    Jia, Fei; Li, Bo; Cao, Yan-Ping; Xie, Wei-Hua; Feng, Xi-Qiao

    2015-01-01

    Three-dimensional surface wrinkling of soft cylindrical tissues induced by differential growth is explored. Differential volumetric growth can cause their morphological stability, leading to the formation of hexagonal and labyrinth wrinkles. During postbuckling, multiple bifurcations and morphological transitions may occur as a consequence of continuous growth in the surface layer. The physical mechanisms underpinning the morphological evolution are examined from the viewpoint of energy. Surface curvature is found to play a regulatory role in the pattern evolution. This study may not only help understand the morphogenesis of soft biological tissues, but also inspire novel routes for creating desired surface patterns of soft materials.

  8. Predicting the patterns in lamellar growth

    NASA Astrophysics Data System (ADS)

    Kirkaldy, J. S.

    1984-12-01

    The removal of the degeneracy in the steady-state diffusion-capillarity relation for the undercooling of lamellar eutectics as a function of forced growth velocity and spacing requires the statement of a global principle. The consequences of Langer's conjecture that "each lamella must grow in a direction which is perpendicular to the solidification front" have been explored. In the first instance it is demonstrated that the principle is equivalent on the isotherm to a conditional minimum in the frontal-surface free energy. Secondly, it is deduced for forced-velocity eutectics that the stable spacing is 2λm, where λm is given by a minimum in the undercooling. Langer and co-workers have been led to favor the value λm on the basis of an unjustified approximation. In contradistinction to Langer's identification of a "diffusive mode" for relaxation of lamellar spacing, we find that the mechanism of stabilization is best described as a damped oscillation in the spacing. The present stable coordinate is identical with that obtained for isothermal structures via Langer's conjecture and by a number of earlier related perturbation arguments. It corresponds to an isothermal state of the spacing which coincides with a maximum in the entropy-production rate. The thermodynamic validation of this principle is briefly discussed.

  9. 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.

  10. Growth patterns of craniopharyngiomas: clinical analysis of 226 patients.

    PubMed

    Pan, Jun; Qi, Songtao; Liu, Yi; Lu, Yuntao; Peng, Junxiang; Zhang, XiAn; Xu, YiKai; Huang, Guang-Long; Fan, Jun

    2016-04-01

    OBJECT Craniopharyngiomas (CPs) are rare epithelial tumors that are often associated with an enigmatic and unpredictable growth pattern. Understanding the growth patterns of these tumors has a direct impact on surgical planning and may enhance the safety of radical tumor removal. The aim of this study was to analyze the growth patterns and surgical treatment of CPs with a focus on the involvement of the hypothalamopituitary axis and the relationship of the tumor to the arachnoid membrane and surrounding structures. METHODS Clinical data from 226 consecutive patients with primary CP were retrospectively reviewed. Tumor location and the relationship of the tumor to the third ventricle floor and the pituitary stalk were evaluated using preoperative MRI and intraoperative findings. A topographic classification scheme was proposed based on the site of tumor origin and tumor development. The clinical relevance of this classification on patient presentation and outcomes was also analyzed. RESULTS The growth of CPs can be broadly divided into 3 groups based on the site of tumor origin and on tumor-meningeal relationships: Group I, infrasellar/infradiaphragmatic CPs (Id-CPs), which mainly occurred in children; Group II, suprasellar subarachnoid extraventricular CPs (Sa-CPs), which were mainly observed in adults and rarely occurred in children; and Group III, suprasellar subpial ventricular CPs (Sp-CPs), which commonly occurred in both adults and children. Tumors in each group may develop complex growth patterns during vertical expansion along the pituitary stalk. Tumor growth patterns were closely related to both clinical presentation and outcomes. Patients with Sp-CPs had more prevalent weight gain than patients with Id-CPs or Sa-CPs; the rates of significant weight gain were 41.7% for children and 16.7% for adults with Sp-CPs, 2.2% and 7.1% for those with Id-CPs, and 12.5% and 2.6% for those with Sa-CPs (p < 0.001). Moreover, patients with Sp-CPs had increased

  11. 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. PMID:24341067

  12. 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.

  13. Population Growth Patterns of Four Species of Aphelenchoides on Fungi

    PubMed Central

    Perper, Timothy; Petriello, Richard

    1977-01-01

    Qualitative and quantitative differences in population growth patterns of Aphelenchoides rutgersi from Florida, A. sacchari from Jamaica, A. dactylocercus from Great Britain, and A. cibolensis from New Mexico were assessed on 28 species of fungi. The patterns of population growth of A. rutgersi and A. sacchari were statistically similar although not identical, and they differed considerably from those of A. dactylocercus and A. cibolensis. It is suggested that A. rutgersi and A. sacchari, from Florida and Jamaica respectively, may be more closely related to each other than to either A. dactylocercus or A. cibolensis. PMID:19305612

  14. Growth of large patterned arrays of neurons using plasma methods

    NASA Astrophysics Data System (ADS)

    Brown, I. G.; Bjornstad, K. A.; Blakely, E. A.; Galvin, J. E.; Monteiro, O. R.; Sangyuenyongpipat, S.

    2003-05-01

    To understand how large systems of neurons communicate, we need to develop, among other things, methods for growing patterned networks of large numbers of neurons. Success with this challenge will be important to our understanding of how the brain works, as well as to the development of novel kinds of computer architecture that may parallel the organization of the brain. We have investigated the use of metal ion implantation using a vacuum-arc ion source, and plasma deposition with a filtered vacuum-arc system, as a means of forming regions of selective neuronal attachment on surfaces. Lithographic patterns created by the treating surface with ion species that enhance or inhibit neuronal cell attachment allow subsequent proliferation and/or differentiation of the neurons to form desired patterned neural arrays. In the work described here, we used glass microscope slides as substrates, and some of the experiments made use of simple masks to form patterns of ion beam or plasma deposition treated regions. PC-12 rat neurons were then cultured on the treated substrates coated with Type I Collagen, and the growth and differentiation was monitored. Particularly good selective growth was obtained using plasma deposition of diamond-like carbon films of about one hundred Angstroms thickness. Neuron proliferation and the elaboration of dendrites and axons after the addition of nerve growth factor both showed excellent contrast, with prolific growth and differentiation on the treated surfaces and very low growth on the untreated surfaces.

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

    PubMed Central

    2016-01-01

    Abstract 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. PMID:26260675

  16. 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.

  17. 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

  18. Growth Patterns of Placental and Paraovarian Adrenocortical Heterotopias Are Different

    PubMed Central

    Xu, Bo; Popiolek, Dorota A.

    2013-01-01

    Two cases of adrenocortical heterotopia are reported. One is in a full-term placenta. The other is adjacent to the ovarian hilum of an adult. Both are incidental findings. Despite sharing similar histological and immunological features, they show different growth patterns. The literature is reviewed and adrenocortical heterotopias of different locations are compared. New hypotheses of its histogenesis are discussed. PMID:24383032

  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. PMID:21553803

  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. PMID:23442731

  1. 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

  2. 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.

  3. 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

  4. Conformal dynamics of fractal growth patterns without randomness

    PubMed

    Davidovitch; Feigenbaum; Hentschel; Procaccia

    2000-08-01

    Many models of fractal growth patterns (such as diffusion limited aggregation and dielectric breakdown models) combine complex geometry with randomness; this double difficulty is a stumbling block to their elucidation. In this paper we introduce a wide class of fractal growth models with highly complex geometry but without any randomness in their growth rules. The models are defined in terms of deterministic itineraries of iterated conformal maps, generating the function Phi((n))(omega) which maps the exterior of the unit circle to the exterior of an n-particle growing aggregate. The complexity of the evolving interfaces is fully contained in the deterministic dynamics of the conformal map Phi((n))(omega). We focus attention on a class of growth models in which the itinerary is quasiperiodic. Such itineraries can be approached via a series of rational approximants. The analytic power gained is used to introduce a scaling theory of the fractal growth patterns and to identify the exponent that determines the fractal dimension.

  5. 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.

  6. Patterning of hydrogenated microcrystalline silicon growth by magnetic field

    SciTech Connect

    Fejfar, A.; Stuchlik, J.; Mates, T.; Ledinsky, M.; Honda, S.; Kocka, J.

    2005-07-04

    A way of influencing growth of silicon films by magnetic field is demonstrated. Permanent magnet(s) placed under the substrate influenced the discharge in a mixture of silane and hydrogen and led to formation of microcrystalline regions in otherwise amorphous film. The pattern of microcrystalline regions varied with the orientation of the magnetic field. Microscopic study by atomic force microscopy and by micro-Raman spectroscopy revealed that the microcrystalline regions resulted from a higher density of crystalline grain nuclei, increased at the locations where the magnetron effect could be expected. This phenomenon could be used to study the transition between amorphous and microcrystalline growth. Moreover, we suggest it as a kind of 'magnetic lithography' for the preparation of predefined microcrystalline patterns in otherwise amorphous silicon films.

  7. Microstructure And Patterning Of Laser Initiated Oxide Growth

    NASA Astrophysics Data System (ADS)

    Boyd, Ian W.

    1989-05-01

    Microstructural studies of silicon dioxide films grown by laser and by traditional means using infrared spectrometry are described. Broad similarities and intriguing thickness dependences are discussed. A new technique of Direct Growth Lithography (DGL) is reported, whereby oxide patterns are selectively and directly grown over significant regions of a silicon wafer, with spatial features extending over a 3mm square area with linewidths down to around one micron.

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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…

  16. Growth pattern and carcase development in male ducks selected for growth rate.

    PubMed

    Maruyama, K; Akbar, M K; Turk, C M

    1999-05-01

    1. Growth patterns of the whole body, eviscerated carcases, breast muscle, leg and thigh muscles and abdominal fat pads were compared in 4 lines (Lines A, B, C, and D) of male ducks selected for market weight (n = 1305) using growth curve analysis, allometric growth analysis and repeated measure analysis. At 49 d of age, Line A was heaviest, followed by Line B, Line C and Line D. 2. Ducks were fed ad libitum under 24-h lighting and 12 or 24 ducks were killed to determine body, carcase, breast-muscle, leg and thigh-muscle, and abdominal fat weights at time points from hatching until 53 d of age. 3. The Weibull function was chosen for growth curve analysis. The asymptote and inflection point from the Weibull growth curves identified 3 lines (Lines B, C, and D) with discrete body and carcase growth patterns but did not distinguish Line A from Line B. In all 4 lines the asymptote ranged from 4437 g to 3008 g for body weight and from 3334 g to 2098 g for carcase weight; the inflection point ranged from 22.5 d to 25.3 d for body weight and from 25.4 d to 29.6 d for carcase weight. 4. The allometric growth coefficient, relative to whole-body growth, was higher than 1.00 for breast muscle and lower than 1.00 for leg and thigh muscles during from 4 d to 53 d of age. 5. Body fat accumulation was estimated by abdominal fat. Line D accumulated more abdominal fat than other lines. The pattern of fat accumulation in Line D was different from Lines A, B and C and there were no differences between Lines A, B and C. PMID:10465391

  17. Dynamics of rod eutectic growth patterns in confined geometry

    NASA Astrophysics Data System (ADS)

    Şerefoǧlu, Melis; Bottin-Rousseau, S.; Akamatsu, S.; Faivre, G.

    2012-01-01

    The dynamics of rod-like eutectics are examined using a directional solidification setup, which allows real-time observation of the whole solidification front in specimens of transparent eutectic alloys -here, succinonitrile-(D)camphor. In steady-state, rod eutectic growth patterns consist of triangular arrays, more or less disturbed by topological defects. In the absence of strong convection and of crystallographic anisotropy, the long-time evolution of the pattern is dominated by "imperfections" of the system, such as misalignment of the temperature gradient, and finite-size. In this study, we present experimental results on the finite-size effects on rod eutectics and show that a rod to lamella transition takes place as a result of finite-size effect only, at a given alloy concentration.

  18. 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

  19. 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

  20. 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

  1. Fractal patterns formed by growth of radial viscous fingers*

    NASA Astrophysics Data System (ADS)

    Praud, Olivier

    2004-03-01

    We examine fractal patterns formed by the injection of air into oil in a thin (0.13 mm) layer contained between two cylindrical glass plates of 288 mm diameter (a Hele-Shaw cell) [1]. The resultant radially grown patterns are similar to those formed in Diffusion Limited Aggregation (DLA), but the relation between the continuum limit of DLA and continuum (Laplacian) growth remains an open question. Our viscous fingering patterns in the limit of very high pressure difference reach an asymptotic state in which they exhibit a fractal dimension of 1.70± 0.02, in good agreement with a calculation of the fractal dimension of a DLA cluster, 1.713± 0.003 [2]. The generalized dimensions are also computed and show that the observed pattern is self-similar with Dq = 1.70 for all q. Further, the probability density function of shielding angles suggests the existence of a critical angle close to 75 degrees. This result is in accord with numerical and analytical evidence of a critical angle in DLA [3]. Thus fractal viscous fingering patterns and Diffusion Limited Aggregation clusters have a similar geometrical structure. *Work conducted in collaboration with H.L. Swinney, M.G. Moore and Eran Sharon [1] E. Sharon, M. G. Moore, W. D. McCormick, and H. L. Swinney, Phys. Rev. Lett. 91, 205504 (2003). [2] B.Davidovitch et A. Levermann and I. Procaccia, Phys. Rev. E 62, 5919 (2000). [3] D. A. Kessler et al., Phys. Rev. E 57, 6913 (1998).

  2. 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.

  3. 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

  4. 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.

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

    PubMed

    Helmi, C; Cracraft, J

    1977-07-01

    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.

  6. 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

  7. Morphologic and molecular evaluation of Chlamydia trachomatis growth in human endocervix reveals distinct growth patterns

    PubMed Central

    Lewis, Maria E.; Belland, Robert J.; AbdelRahman, Yasser M.; Beatty, Wandy L.; Aiyar, Ashok A.; Zea, Arnold H.; Greene, Sheila J.; Marrero, Luis; Buckner, Lyndsey R.; Tate, David J.; McGowin, Chris L.; Kozlowski, Pamela A.; O'Brien, Michelle; Lillis, Rebecca A.; Martin, David H.; Quayle, Alison J.

    2014-01-01

    In vitro models of Chlamydia trachomatis growth have long been studied to predict growth in vivo. Alternative or persistent growth modes in vitro have been shown to occur under the influence of numerous stressors but have not been studied in vivo. Here, we report the development of methods for sampling human infections from the endocervix in a manner that permits a multifaceted analysis of the bacteria, host and the endocervical environment. Our approach permits evaluating total bacterial load, transcriptional patterns, morphology by immunofluorescence and electron microscopy, and levels of cytokines and nutrients in the infection microenvironment. By applying this approach to two pilot patients with disparate infections, we have determined that their contrasting growth patterns correlate with strikingly distinct transcriptional biomarkers, and are associated with differences in local levels of IFNγ. Our multifaceted approach will be useful to dissect infections in the human host and be useful in identifying patients at risk for chronic disease. Importantly, the molecular and morphological analyses described here indicate that persistent growth forms can be isolated from the human endocervix when the infection microenvironment resembles the in vitro model of IFNγ-induced persistence. PMID:24959423

  8. 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. PMID:24376375

  9. 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

  10. Atypical growth pattern of a meningioma in an adult.

    PubMed

    Lanotte, Michele; Perez, Rosa; Boccaletti, Riccardo; Castellano, Isabella; Cassoni, Paola; Ducati, Alessandro

    2007-08-01

    A 49-year-old woman presented with a rare atypical growth pattern of meningioma without evidence of dural attachment manifesting as chronic headache associated with transient paresthesia and left motor disorders. On admission, neurological examination showed no abnormalities. Magnetic resonance (MR) imaging revealed a right temporo-parieto-occipital lesion, which appeared to involve the subdural space and filling the cortical sulci. The lesion caused peritumoral white matter edema. The tumor appeared hypointense on T(1)-weighted and hyperintense on T(2)-weighted MR images, with homogeneous enhancement after contrast administration. A biopsy of the lesion was performed. Histological examination indicated that the lesion was a meningioma. Intraparenchymal meningiomas should be considered in the differential diagnosis of intraaxial lesions in patients of any age.

  11. Patterns of epidermal growth factor receptor amplification in malignant gliomas.

    PubMed Central

    Sauter, G.; Maeda, T.; Waldman, F. M.; Davis, R. L.; Feuerstein, B. G.

    1996-01-01

    Amplification of the gene for epidermal growth factor receptor (EGFR) is a common finding in malignant gliomas. We found that 18 of 29 grade 3 and grade 4 gliomas had EGFR amplification when assayed using fluorescence in situ hybridization. The amplification pattern suggests that the amplicon is contained within double minute chromosomes in most cases. EGFR copy number can differ by 20-fold in amplified cells within a single case. Polysomy 7 occurs frequently in both EGFR-amplified and -unamplified cells. More than one-third of the cases had < or = 10 percent of cells with amplified EGFR, and it is likely that these cases would not have been identified by methods that do not examine DNA on a cell by cell basis. Images Figure 1 PMID:8644846

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

    PubMed Central

    2011-01-01

    Introduction 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. Materials and methods 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. Results 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. Conclusions 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. PMID:22142280

  13. Cell growth pattern and wall microfibrillar arrangement: experiments with nitella.

    PubMed

    Gertel, E T; Green, P B

    1977-08-01

    In cylindrical cells growing throughout their length, over-all transverse reinforcement of the wall by microfibrils is believed to be required for cell elongation. The multinet theory states that in such cells microfibrils are deposited at the inner surface of the wall with transverse orientation and are then passively reoriented toward the longitudinal direction by the predominant longitudinal strain (surface expension). In the present study young Nitella cells were physically forced to grow in highly abnormal patterns: in length only, in girth only, or with localized suppression of growth. Subsequent gradients of microfibrillar arrangement within the wall cross-section were measured with polarized light and interference microscopes. The novel wall structures produced were in all cases explainable by passive reorientation, i.e. by the multinet theory. The study also showed that orientation of synthesis remains insensitive to several of the physical manipulations that strongly influence the passive behavior of wall microfibrils. Only the localized complete suppression of surface growth led to the deposition of nontransverse cellulose. These results suggest that the presence of strain is needed for continued oriented synthesis, but that the directional aspect of strain is not an "instructional" agent continuously guiding the orientation of synthesis, once this orientation has been established.

  14. Patterns of growth and malnutrition among preschoolers in Belize.

    PubMed

    Jenkins, C L

    1981-10-01

    An anthropometric survey of 750 preschoolers was conducted 1979 in Belize to assess nutritional status in two districts, one coastal and the other inland. Mothers were interviewed concerning reproductive history, child's health and dietary history, and associated factors. Analysis included the recognition of low arm circumference, weight-for-age, stature-for-age, and weight-for-stature. Survey results indicate that about 25% of the children, birth to 5 years old, show evidence of stunting, while 2.5% show evidence of wasting. Comparisons of rates of malnutrition by ethnic group reveal the Maya and Garifuna (Black Carib) children are significantly more commonly malnourished than others. Applying a discriminant function to groups of children designated as "poor" and "better-than-average" growth classes reveals several factors which may be contributory to the etiology of preschool malnutrition in Belize. the frequency of diarrhea and age at introduction to sold foods, are significantly related to growth retardation among preschoolers. Analysis of 24-hour-diet recalls corroborates the patterning of malnutrition among the ethnic groups. PMID:6798879

  15. 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.

  16. Growth patterns of school-children in Bahrain.

    PubMed

    Musaiger, A O; Gregory, W B; Haas, J D

    1989-01-01

    The aim of this study is to assess physical growth of school children in Bahrain. Cross-sectional data on 1593 children (818 boys and 775 girls), aged 6.5 to 18.5 years were collected in 1986. Anthropometric measures included height, weight, mid-arm circumference, triceps, biceps, subscapular and suprailiac skinfold thickness. At all ages median (P50) heights and weights of Bahraini boys and girls are below the 50th percentiles of the North American reference standard (NCHS). Median heights of both Bahraini sexes falls between the 25th and 5th percentiles of the reference data. As for weight, the median of boys fluctuates between the 25th and 5th percentiles, while that of girls fluctuates between the 50th and 10th percentiles of the standard. When compared to the American standard, median triceps skinfold of Bahraini boys and girls falls between the 50th and 25th percentiles. The median arm circumference of both sexes is close to the 5th percentiles. In general, the skinfold measurements indicate a high subcutaneous fat store, suggesting a lack of muscle development. Health, genetic and other factors associated with growth patterns of Bahraini children are discussed.

  17. 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.

  18. 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…

  19. Bibliometric analysis on retinoblastoma literatures in PubMed during 1929 to 2010

    PubMed Central

    Zhao, Zhi-Guang; Guo, Xue-Gang; Xu, Chang-Tai; Pan, Bo-Rong; Xu, Li-Xian

    2011-01-01

    AIM To determine the growth rule and tendency of retinoblastoma (Rb) literature, and to provide the basis for research of diagnosis, treatment and on Rb. METHODS Bibliometric analyses were carried out on Rb literatures which contain the descriptors of Rb in their titles or texts from 1929 to 2010 in PubMed database (www.ncbi.nlm.nih.gov/Pubmed). The biomedical journals referring to Rb by using bibliometric indicators were calculated. The principal bibliometric indicators, i.e., Price's and Bradford's laws to the increase or distribution of scientific literature, the participation index of languages and the journals were applied. By means of manual coding, Rb documents were classified according to documents studied and to statistical analysis. RESULTS During 1929-2010, there were 16162 literatures in the PubMed database including the word Rb. According to the literature type, it includes Review (n=2026), Randomized Controlled Trial (n=7), Practice guideline (n=3), meta-analysis (n=4), letter (n=215), editorial (n=98), clinical trial (n=115) and others (n=13694). By the statistical analysis, its equation is near power index (y=3.0477x2.6088, R2=0.9666). From 1929 to 2010, Rb literatures in English were primarily dominant (90.71%) and the amount of the literature in Chinese ranked the fourth (1.37%). By searching PubMed, 1420(8.8%) literatures covered were from 41 of 48 ophthalmological, and 406 (2.5%) literatures from 44 of 86 pediatrics journals that correlated with retinoblastoma (SCI-indexed). The data showed that the literatures of Rb were gradually increasing year by year and were approximate near power index during 1929-2010, and the document publishes published mainly in ophthalmological journals, and in English (90.71%), and showing that the study on Rb is a popular subject in the last half century. CONCLUSION The literatures of Rb are gradually increasing, mainly English in ophthalmologic journals. PMID:22553624

  20. 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.

  1. 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

  2. [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. PMID:20387426

  3. [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.

  4. 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

  5. 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

  6. Growth patterns in the orbital region: a morphometric study.

    PubMed

    Farkas, L G; Posnick, J C; Hreczko, T M; Pron, G E

    1992-07-01

    Data for analysis of age-related changes in growth in the intercanthal (en-en) and biocular (ex-ex) widths were obtained from 1,594 healthy North American Caucasians in age groups from 1 to 18 years, divided equally between males and females. At 1 year, the degree of development of the intercanthal width reached 84.1%, and that of the biocular width 85.9% of adults in both sexes. The levels of growth achieved by 5 years of age rose to 93.3% in the intercanthal width and 88.1% in the biocular width, in both sexes. The average total growth increments achieved between ages 1 and 18 years were 5.2 mm in the intercanthal width and 12.5 mm in the biocular. The intercanthal width showed very little growth after 1 year of age; in contrast, the biocular width showed significantly greater growth increments both before and after 5 years of age. Rapid growth was observed between 3 and 4 years in the intercanthal width of both sexes. The age-related growth observed in the biocular width was small but continuous up to maturation time. The intercanthal width reached full maturation at 8 years in females and 11 years in males, and the biocular width at 13 years in females and 15 years in males. PMID:1643059

  7. Growth patterns in the orbital region: a morphometric study.

    PubMed

    Farkas, L G; Posnick, J C; Hreczko, T M; Pron, G E

    1992-07-01

    Data for analysis of age-related changes in growth in the intercanthal (en-en) and biocular (ex-ex) widths were obtained from 1,594 healthy North American Caucasians in age groups from 1 to 18 years, divided equally between males and females. At 1 year, the degree of development of the intercanthal width reached 84.1%, and that of the biocular width 85.9% of adults in both sexes. The levels of growth achieved by 5 years of age rose to 93.3% in the intercanthal width and 88.1% in the biocular width, in both sexes. The average total growth increments achieved between ages 1 and 18 years were 5.2 mm in the intercanthal width and 12.5 mm in the biocular. The intercanthal width showed very little growth after 1 year of age; in contrast, the biocular width showed significantly greater growth increments both before and after 5 years of age. Rapid growth was observed between 3 and 4 years in the intercanthal width of both sexes. The age-related growth observed in the biocular width was small but continuous up to maturation time. The intercanthal width reached full maturation at 8 years in females and 11 years in males, and the biocular width at 13 years in females and 15 years in males.

  8. Pattern of growth retardation after Blount stapling: a roentgen stereophotogrammetric analysis.

    PubMed

    Bylander, B; Hansson, L I; Selvik, G

    1983-02-01

    The roentgen stereophotogrammetric method has been used in 19 children treated by Blount stapling for progressive leg length discrepancy. The growth plates of distal femur and/or proximal tibia were stapled with a total of 31 growth regions stapled. Longitudinal growth rate of 25 intact growth regions of distal femur and proximal tibia was determined and correlated well to growth rates as derived from growth tables of Green and Anderson and Kember and Sissons. In stapled growth regions, a uniform pattern of growth retardation was found and correlated well to skeletal age: the more advanced the skeletal age at time of stapling, the more pronounced and rapid initial growth retardation and the lower basal growth rate. Significant asymmetric growth was registered in 5 of 31 stapled growth regions, especially in three patients who developed loosening of staples. In five patients the staple tip motion was analyzed. Widening of staples and staple tip movements within the bony epiphysis and metaphysis were small. In the skeletally younger cases the widening and tip movement were more pronounced than in the older cases. In summary, the roentgen stereophotogrammetric method was used in order to analyze pre- and postoperative growth pattern and was found valuable in checking growth rates after Blount stapling to detect early complications such as asymmetric growth and loosening of staples. Furthermore, the movements and the deformation of the staples by the growth process could be evaluated with high precision.

  9. 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

  10. 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/.

  11. Association between mandibular posterior alveolar morphology and growth pattern in a Chinese population with normal occlusion*

    PubMed Central

    Han, Min; Wang, Rong-yang; Liu, Hong; Zhu, Xiu-juan; Wei, Fu-lan; Lv, Tao; Wang, Na-na; Hu, Li-hua; Li, Guo-ju; Liu, Dong-xu; Wang, Chun-ling

    2013-01-01

    Objective: To investigate the relationship between growth patterns and mandibular posterior tooth-alveolar bone complex morphology in a Chinese population with normal occlusion. Methods: Forty-five patients with normal occlusion (23 males, 22 females) were included in this study. Among these patients, 20 displayed the vertical growth pattern, and 20 had the horizontal growth pattern, while the remaining patients displayed the average growth pattern. All of the patients underwent dental cone beam computed tomography (CBCT), which included the region of the mandibular posterior teeth and the alveolar. A linear regression analysis and a correlation analysis between the facial height index (FHI) and the alveolar bone morphology were performed. Results: The inclination of the molars, the thickness of the cortical bone, and the height of the mandibular bone differed significantly between patients with the horizontal growth pattern and those with the vertical growth pattern (P<0.05). Significant positive correlations were found between: the FHI and the inclination of the molars; the FHI and the thickness of the cortical bone; and the FHI and the height of the mandibular bone. Conclusions: The mandibular posterior tooth-alveolar bone complex morphology may be affected by growth patterns. PMID:23303628

  12. 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.

  13. 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.

  14. Growth of SiC single crystals on patterned seeds by a sublimation method

    NASA Astrophysics Data System (ADS)

    Yang, Xianglong; Chen, Xiufang; Peng, Yan; Xu, Xiangang; Hu, Xiaobo

    2016-04-01

    Growth of 6H-SiC on patterned seeds with the vertical sidewalls composed of {11-20} and {1-100} faces by a sublimation method at 1700-2000 °C was studied. Anisotropy in lateral growth rates was observed, i.e the growth rate towards <11-20> was faster than that along <1-100>. It was found that free lateral growth on mesas was accompanied by a sharp decrease in the density of threading dislocation. The dependence of lateral growth rate on growth conditions such as reactor pressure and growth temperature was investigated. The factors governing the process of lateral growth of 6H-SiC on patterned seeds were discussed.

  15. 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. PMID:21854163

  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. 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. Growth patterns of the nasolabial region: a morphometric study.

    PubMed

    Farkas, L G; Posnick, J C; Hreczko, T M; Pron, G E

    1992-07-01

    Age-related growth changes in the nasolabial region were analyzed through six measurements taken between 1 year and 18 years of age in 1,593 North American Caucasians. By 1 year of age, the length of the cutaneous portion of the upper lip and the width of the nose showed the highest levels of development compared with their adult size, 80.3 and 79.5%, respectively. By 5 years, the developmental level of the nasolabial region except nasal tip protrusion approached their maturation level. Our nasal measurements indicated that growth of the nose between 5 and 18 years was significantly greater than that of the upper lip, which revealed significantly greater growth increments between 1 and 5 years of age. The cutaneous upper lip height reached its adult size in 3-year-old females (12.7 mm) and 6-year-old males (14.4 mm). Nose width and height were fully developed in females by age 12 and in males by age 14 or 15. Rapid growth occurred in the upper lip, nose height, and nasal tip protrusion between the ages of 1 and 4 years. Knowledge of these age-related morphologic variations within the nose and upper lip may be useful in planning the time and type of reconstructive surgery and in anticipating further change in the operated regions after the surgical reconstruction. PMID:1643060

  19. 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…

  20. 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…

  1. Experiments on LICHEN growth. 1. Seasonal patterns and environmental controls

    SciTech Connect

    Benedict, J.B. )

    1990-08-01

    Radial growth of mature Xanthoparmelia lineola and X. subdecipiens thalli (n = 10 thalli, 170 lobes) was measured bimonthly for 2 yr at a transplant locality on the East Slope of the Colorado Front Range (altitude 2,565 m). Growth occurred during every measurement period, but was most rapid in May, June, July, and August. Ninety-three percent of seasonal growth-rate variation during the first year of the study, and 92% during the second year, are explained by differences in the duration of daytime, snow-free thallus moisture (moisture available for photosynthesis); the strength of the relationship suggests that a positive net carbon assimilation rate is translated almost immediately into lobe elongation. No negative correlation was found between radial growth and thallus moisture recorded at night or beneath snow. In the cool, continental environment of the study area, duration of photosynthetically significant thallus moisture is influenced more strongly by air temperature, day length, and snow cover than by total precipitation. At higher altitudes and latitudes, where lichenometry is used for dating, these factors will have even greater importance.

  2. 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.

  3. Growth patterns of the nasolabial region: a morphometric study.

    PubMed

    Farkas, L G; Posnick, J C; Hreczko, T M; Pron, G E

    1992-07-01

    Age-related growth changes in the nasolabial region were analyzed through six measurements taken between 1 year and 18 years of age in 1,593 North American Caucasians. By 1 year of age, the length of the cutaneous portion of the upper lip and the width of the nose showed the highest levels of development compared with their adult size, 80.3 and 79.5%, respectively. By 5 years, the developmental level of the nasolabial region except nasal tip protrusion approached their maturation level. Our nasal measurements indicated that growth of the nose between 5 and 18 years was significantly greater than that of the upper lip, which revealed significantly greater growth increments between 1 and 5 years of age. The cutaneous upper lip height reached its adult size in 3-year-old females (12.7 mm) and 6-year-old males (14.4 mm). Nose width and height were fully developed in females by age 12 and in males by age 14 or 15. Rapid growth occurred in the upper lip, nose height, and nasal tip protrusion between the ages of 1 and 4 years. Knowledge of these age-related morphologic variations within the nose and upper lip may be useful in planning the time and type of reconstructive surgery and in anticipating further change in the operated regions after the surgical reconstruction.

  4. 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

  5. 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

  6. 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.

  7. 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. PMID:21246707

  8. Cellular and Muscular Growth Patterns During Sipunculan Development

    PubMed Central

    KRISTOF, ALEN; WOLLESEN, TIM; MAIOROVA, ANASTASSYA S.; WANNINGER, ANDREAS

    2015-01-01

    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. PMID:21246707

  9. Effects of systemic hyperthermia on the growth patterns of experimental neoplasms.

    PubMed

    Bland, K I; Hodge, K M; Bean, R J; Akin, J R; Fry, D E

    1982-04-01

    Hyperthermia has been shown to have a detrimental effect on experimental and human neoplasms. A water bath immersion system is described to evaluate the effects of systemic hyperthermia (SH) on the growth patterns of the Morris hepatoma 7777 in male Buffalo rats. SH and anesthesia were observed to have no long-term detrimental effects on weight trends or chow consumption. Inhibition of growth was demonstrated for this experimental tumor model at extreme SH (41.5 degree to 42.0 degree C), and it was statistically different (P less than 0.01) from the patterns of tumor growth observed in controls and tumor-burdened animals treated with moderate SH (39..5 degree to 40.0 degree C). Cessation of extreme SH resulted in acceleration of tumor growth so that no difference in tumor volume or animal survival was identified SH resulted in retardation of tumor growth patterns, but its effects were not sustained once treatments were stopped.

  10. Spontaneous Pattern Formation of Surface Nanodroplets from Competitive Growth

    NASA Astrophysics Data System (ADS)

    Lohse, Detlef; Peng, Shuhua; Zhang, Xuehua

    Nanoscale droplets on a substrate are of great interest because of their relevance for droplet-based technologies for light manipulation, lab-on-chip devices, miniaturised reactors, encapsulation and many others. In this work, we establish a basic principle for the symmetrical arrangement of surface nanodroplets during their growth under simple flow conditions. In our model system, nanodroplets nucleate at the rim of spherical cap microstructures on a substrate, due to a pulse of oversaturation is supplied by a solvent exchange process. We find that, while growing at the rim of the microcap, the nanodroplets self-organise into highly symmetric arrangements, with respect to position, size, and mutual distance. The angle between the neighbouring droplets is four times the ratio between the base radii of the droplets and the spherical caps. We show and explain how the nanodroplets acquire the symmetrical spatial arrangement during their competitive growth and why and how the competition enhances the overall growth rate of the nucle- ated nanodroplets. This mechanism behind the nanodroplet self-organisation promises a simple approach for the location control of droplets with a volume down to attoliters.

  11. Spontaneous Pattern Formation of Surface Nanodroplets from Competitive Growth

    NASA Astrophysics Data System (ADS)

    Peng, Shuhua; Lohse, Detlef; Zhang, Xuehua; Xuehua Zhang Team; Detlef Lohse Collaboration

    2015-11-01

    Nanoscale droplets on a substrate are of great interest because of their relevance for droplet-based technologies for light manipulation, lab-on-chip devices, miniaturised reactors, encapsulation and many others. In this work, we establish a basic principle for the symmetrical arrangement of surface nanodroplets during their growth under simple flow conditions. In our model system, nanodroplets nucleate at the rim of spherical cap microstructures on a substrate, as a pulse of oversaturation is supplied by a solvent exchange process. We find that, while growing, the nanodroplets self-organise into highly symmetric arrangements, with respect to position, size, and mutual distance. The angle between the neighbouring droplets is four times the ratio between the base radii of the droplets and the spherical caps. We show and explain how the nanodroplets acquire the symmetrical spatial arrangement during their competitive growth and why and how the competition enhances the overall growth rate of the nucleated nanodroplets. This mechanism behind the nanodroplet self-organisation promises a simple approach for the location control of droplets with a volume down to attoliters.

  12. A Preliminary Investigation of Within-Year Growth Patterns in Reading and Mathematics Curriculum-Based Measures

    ERIC Educational Resources Information Center

    Graney, Suzanne B.; Missall, Kristen N.; Martinez, Rebecca S.; Bergstrom, Melissa

    2009-01-01

    This study examined patterns of growth across benchmark assessments for curriculum-based measures (CBM) over 2 academic years, with the twofold purpose of replicating earlier findings of growth patterns on R-CBM and conducting a preliminary investigation of growth patterns on M-CBM and CBM-Maze. The sample included 898 cases from 3rd through 5th…

  13. 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

  14. 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...

  15. Voronoi Cell Patterns: theoretical model and application to submonolayer growth

    NASA Astrophysics Data System (ADS)

    González, Diego Luis; Einstein, T. L.

    2012-02-01

    We use a simple fragmentation model to describe the statistical behavior of the Voronoi cell patterns generated by a homogeneous and isotropic set of points in 1D and in 2D. In particular, we are interested in the distribution of sizes of these Voronoi cells. Our model is completely defined by two probability distributions in 1D and again in 2D, the probability to add a new point inside an existing cell and the probability that this new point is at a particular position relative to the preexisting point inside this cell. In 1D the first distribution depends on a single parameter while the second distribution is defined through a fragmentation kernel; in 2D both distributions depend on a single parameter. The fragmentation kernel and the control parameters are closely related to the physical properties of the specific system under study. We apply our model to describe the Voronoi cell patterns of island nucleation for critical island sizes i=0,1,2,3. Experimental results for the Voronoi cells of InAs/GaAs quantum dots are also described by our model.

  16. Bacterial locomotion, adsorption and growth over chemically patterned surfaces

    NASA Astrophysics Data System (ADS)

    Jalali, Maryam; Molaei, Mehdi; Sheng, Jian

    2013-11-01

    Complex dynamic interactions between bacteria and chemically patched interface that mimics the heterogeneous energy landscape of a real-life interfacial environment are studied in the paper. We explore effects of these spatially varying chemical patches on bacterial locomotion, adsorption, biofilm formation and the film growth rate. Using micro-fabrication and soft-lithography, we have fabricated PDMS microfluidic channels with a solid substrate covered by micro-scale chemical patches. Arrays of 2D geometries of characteristic scales varying from 10 to 50 μm are transferred onto a glass substrate by soft-lithography. The substrate is functionalized to generate alternating hydrophobic and hydrophilic regions and bonded with the channel. The 3D swimming characteristics near these surfaces, such as swimming velocity, linear and angular dispersions, are measured in-situ using 3D digital holographic microscopy. The observations are used to examine the mechanisms involved in adsorption and desorption of swimming bacteria onto the substrate. Long-term experiments are conducted to quantify the growth rate and structures of colony. A correlation between various length scales of the substrate and bacteria motility are observed.

  17. Pattern formation in crystal growth under parabolic shear flow.

    PubMed

    Ueno, K

    2003-08-01

    Morphological instability of the solid-liquid interface occurring in a crystal growing from an undercooled thin liquid bounded on one side by a free surface and flowing down inclined plane, is investigated by a linear stability analysis under shear flow. It is found that restoring forces due to gravity and surface tension is an important factor for stabilization of the solid-liquid interface on long length scales. This is a stabilizing effect different from the Gibbs-Thomson effect. A particular long wavelength mode of about 1 cm of wavy pattern, observed on the surface of icicles covered with a thin layer of flowing water is obtained from the dispersion relation, including the effect of flow and restoring forces.

  18. 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

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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. PMID:26125556

  5. Clinical significance of subepithelial growth patterns in non-muscle invasive bladder cancer

    PubMed Central

    2011-01-01

    Background We evaluated the clinical significance and prognostic value of histopathological features of bladder cancer, such as subepithelial growth patterns and tumor growth pattern at the invasion front. Methods In total, 130 patients newly diagnosed with non-muscle invasive bladder cancer and underwent transurethral resection between 1998 and 2009 were enrolled. Subepithelial growth patterns consisting of endophytic growth pattern (EGP) and von Brunn's nest involvement (VBNI) were investigated using hematoxylin and eosin-stained slides, and their frequency of occurrence, prognostic value, and correlation with other clinicopathological features was evaluated. Results EGP and VBNI were found in 40 (30.8%) and 5 (3.9%) of the 130 cases, respectively. Of the 26 pT1 tumors, the growth pattern at the invasion front was trabecular in 17 (65.4%) and infiltrative in 9 (34.6%). Although 8 (47.1%) of 17 trabecular tumors coexisted with EGP, no cases with infiltrative tumors had EGP (p = 0.023). VBNI correlated with high tumor grades (p = 0.006) and lymphovascular involvement (p = 0.026). The multivariate Cox proportional hazards analysis revealed that tumor diameter less than 3 cm (p = 0.04) and intravesical bacillus Calmette-Guérin therapy (p = 0.004) were independent favorable prognostic factors for recurrence-free survival, whereas tumor stage was an independent poor prognostic factor for disease progression (p = 0.006). Conclusions Subepithelial growth patterns were not a significant prognostic factor in this study. Additionally, no tumors with an infiltrative growth pattern coexisted with EGP, suggesting that determining the presence of EGP might be helpful for managing non-muscle invasive bladder cancers. PMID:21816111

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

    PubMed

    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.

  7. 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

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

    PubMed

    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

  9. 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. PMID:26458559

  10. 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.

  11. The inclusion of an online journal in PubMed central - a difficult path.

    PubMed

    Grech, Victor

    2016-01-01

    The indexing of a journal in a prominent database (such as PubMed) is an important imprimatur. Journals accepted for inclusion in PubMed Central (PMC) are automatically indexed in PubMed but must provide the entire contents of their publications as XML-tagged (Extensible Markup Language) data files compliant with PubMed's document type definition (DTD). This paper describes the various attempts that the journal Images in Paediatric Cardiology made in its efforts to convert the journal contents (including all of the extant backlog) to PMC-compliant XML for archiving and indexing in PubMed after the journal was accepted for inclusion by the database. PMID:27244254

  12. 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

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. Patterns of fluctuating asymmetry in developing primary feathers: a test of the compensational growth hypothesis

    PubMed Central

    Aparicio, J. M.

    1998-01-01

    The study of asymmetry ontogeny may reveal the mechanisms controlling the development of bilaterally symmetrical characters and the causes of asymmetry. In birds, flight feather asymmetries appear to increase at the beginning of growth and decrease at the end of their development. It has been proposed that such a pattern could be proximately caused by a developmental mechanism of compensational growth between the left and right wings, which should act to restore trait symmetry at the end of growth. In this study, I tested the hypothesis of the existence of a mechanism of compensational growth by performing an experiment, which consisted of provoking small asymmetries in the seventh primary feathers of house sparrows (Passer domesticus) by inducing the two feathers (one each side) to moult two days apart. On each side, the feathers grew in a similar way, independently of the growth of the other side. Feather length asymmetries were shortened with the advance of growth. However, the differences in time of growth persisted throughout development. These results do not support the existence of a mechanism of compensational growth. Primary feathers' asymmetries could decrease at the end of growth because the growth of the two feathers follows a programmed trajectory, which tends towards a certain maximum potential size.

  18. Dermatoscopic features of cutaneous non-facial non-acral lentiginous growth pattern melanomas

    PubMed Central

    Keir, Jeff

    2014-01-01

    Background: The dermatoscopic features of facial lentigo maligna (LM), facial lentigo maligna melanoma (LMM) and acral lentiginous melanoma (ALM) have been well described. This is the first description of the dermatoscopic appearance of a clinical series of cutaneous non-facial non-acral lentiginous growth pattern melanomas. Objective: To describe the dermatoscopic features of a series of cutaneous non-facial non-acral lentiginous growth pattern melanomas in an Australian skin cancer practice. Method: Single observer retrospective analysis of dermatoscopic images of a one-year series of cutaneous non-facial, non-acral melanomas reported as having a lentiginous growth pattern detected in an open access primary care skin cancer clinic in Australia. Lesions were scored for presence of classical criteria for facial LM; modified pattern analysis (“Chaos and Clues”) criteria; and the presence of two novel criteria: a lentigo-like pigment pattern lacking a lentigo-like border, and large polygons. Results: 20 melanomas occurring in 14 female and 6 male patients were included. Average patient age was 64 years (range: 44–83). Lesion distribution was: trunk 35%; upper limb 40%; and lower limb 25%. The incidences of criteria identified were: asymmetry of color or pattern (100%); lentigo-like pigment pattern lacking a lentigo-like border (90%); asymmetrically pigmented follicular openings (APFO’s) (70%); grey blue structures (70%); large polygons (45%); eccentric structureless area (15%); bright white lines (5%). 20% of the lesions had only the novel criteria and/or APFO’s. Limitations: Single observer, single center retrospective study. Conclusions: Cutaneous non-facial non-acral melanomas with a lentiginous growth pattern may have none or very few traditional criteria for the diagnosis of melanoma. Criteria that are logically expected in lesions with a lentiginous growth pattern (lentigo-like pigment pattern lacking a lentigo-like border, APFO’s) and the novel

  19. 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

  20. 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…

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  2. Catalyst-free growth of nanocrystalline graphene/graphite patterns from photoresist.

    PubMed

    Zhang, Zengxing; Ge, Binghui; Guo, Yunxian; Tang, Dongsheng; Wang, Xiaojuan; Wang, Fengli

    2013-04-01

    Catalyst-free growth of a nanocrystalline few-layer graphene (or graphite) film from photoresist on variable substrates was demonstrated. The thickness of the film can be easily controlled from 1 nm to hundreds of nanometers. With this method, graphene/graphite patterns with different thicknesses have been designed for integrated electronics. PMID:23439870

  3. 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.

  4. Changes in plasma growth hormone (GH) and secretion patterns of GH and luteinizing hormone in buffaloes (Bubalus bubalis) during growth.

    PubMed

    Mondal, Mohan; Prakash, B S

    2004-08-01

    To assess the changes of plasma growth hormone (GH) and secretion patterns of GH and luteinizing hormone (LH) during growth in buffaloes, six growing female Murrah buffalo calves (mean age 6+/-0.9 months and body weight 66+/-6 kg) were selected. Plasma samples were collected twice a week for 52 weeks for GH and LH assay. To examine for pulsatile secretion samples were collected at 15 minutes interval for 9 hr at weeks 6 and 42 for GH and LH measurements. Plasma progesterone was also estimated in twice-a-week samples to assess whether any of the buffalo had begun ovarian cyclicity. The body weight of all animals was recorded at weekly interval. Plasma GH concentration decreased (P < 0.01) only up to week 29 and showed an increasing trend (P < 0.01) thereafter. The ratio of plasma GH to body weight declined (P < 0.01) throughout the entire experimental period. Plasma GH showed a declining trend only up to when the animals attained 155 kg body weight and thereafter showed an increasing trend (P < 0.01). Plasma GH revealed distinct pulsatile patterns of release, with a mean of 6 and 5 pulses in the 6-week and 42-week samples, respectively. The plasma LH concentrations around the 42-week time period were significantly higher (P < 0.01) than at the 6-week time period, and they exhibited pulsatility. No animal reached puberty until the end of the experiment. In summary, plasma GH levels have a definite pattern of change during growth and patterns of secretion of plasma GH and LH also have a relation with body weight in this species of animal. PMID:15554346

  5. Patterned growth of neuronal cells on modified diamond-like carbon substrates.

    PubMed

    Kelly, Stephen; Regan, Edward M; Uney, James B; Dick, Andrew D; McGeehan, Joseph P; Mayer, Eric J; Claeyssens, Frederik

    2008-06-01

    Diamond-like carbon (DLC) has been explored as a biomaterial with potential use for coating implantable devices and surgical instruments. In this study the interaction of DLC with mammalian neuronal cells has been studied along with its modifications to improve its function as a biomaterial. We describe the use of DLC, oxidised DLC and phosphorus-doped DLC to support the growth and survival of primary central nervous system neurones and neuroblastoma cells. None of these substrates were cytotoxic and primary neurones adhered better to phosphorus-doped DLC than unmodified DLC. This property was used to culture cortical neurones in a predetermined micropattern. This raises the potential of DLC as a biomaterial for central nervous system (CNS) implantation. Furthermore, patterned DLC and phosphorus-doped DLC can direct neuronal growth, generating a powerful tool to study neuronal networks in a spatially distinct way. This study reports the generation of nerve cell patterns via patterned deposition of DLC.

  6. 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.

  7. Selective Growth of α-Sexithiophene by Using Silicon Oxides Patterns

    PubMed Central

    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/SiOx substrates by driving the orientation of growth. This process combines the parallel local anodic oxidation of Si/SiOx 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 cm2. 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. PMID:22016622

  8. 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.

  9. 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

  10. 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

  11. 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

  12. Growth pattern of the maxillary sinus in the miniature pig (Sus scrofa).

    PubMed

    Koppe, T; Klauke, T; Lee, S H; Schumacher, G

    2000-01-01

    The biological role of the paranasal sinuses is obscure, can be elucidated through a cross-sectional growth study of the maxillary sinus in miniature pigs. The maxillary sinus area was obtained from lateral cephalograms of left skull halves of 103 female miniature pigs of known ages, from newborn to 24 months. Out of several nonlinear models, the growth of the maxillary sinus was best described with the Gompertz model. The first derivative of the Gompertz curve revealed an increase in the growth rates of the maxillary sinus until 4 months, after which sinus growth slowed down. The eruption of the permanent molars did not seem to have a significant influence on this growth pattern. Furthermore, growth in maxillary sinus size in the miniature pig does not follow growth in skull size closely, which showed the highest growth rates in newborn animals. In addition, a correlation analysis revealed that the relationship between maxillary sinus area and different characteristics of the masticatory apparatus (including linear cranial dimensions, and the dry weight of the masseter and zygomatico-mandibularis muscles) were influenced greatly by skull size. These results suggest that the existence of pneumatic cavities within the mammalian skull is not satisfactorily explained solely by an architectural theory. Epigenetic factors are likely to influence the final shape of the maxillary sinus.

  13. 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.

  14. 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.

  15. 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.

  16. Estimated in vivo postnatal surface growth patterns of the ovine main pulmonary artery and ascending aorta.

    PubMed

    Fata, Bahar; Gottlieb, Danielle; Mayer, John E; Sacks, Michael S

    2013-07-01

    Delineating the normal postnatal development of the pulmonary artery (PA) and ascending aorta (AA) can inform our understanding of congenital abnormalities, as well as pulmonary and systolic hypertension. We thus conducted the following study to delineate the PA and AA postnatal growth deformation characteristics in an ovine model. MR images were obtained from endoluminal surfaces of 11 animals whose ages ranged from 1.5 months/15.3 kg mass (very young) to 12 months/56.6 kg mass (adult). A bicubic Hermite finite element surface representation was developed for the each artery from each animal. Under the assumption that the relative locations of surface points were retained during growth, the individual animal surface fits were subsequently used to develop a method to estimate the time-evolving local effective surface growth (relative to the youngest measured animal) in the end-diastolic state. Results indicated that the spatial and temporal surface growth deformation patterns of both arteries, especially in the circumferential direction, were heterogeneous, leading to an increase in taper and increase in cross-sectional ellipticity of the PA. The longitudinal PA growth stretch of a large segment on the posterior wall reached 2.57 ± 0.078 (mean ± SD) at the adult stage. In contrast, the longitudinal growth of the AA was smaller and more uniform (1.80 ± 0.047). Interestingly, a region of the medial wall of both arteries where both arteries are in contact showed smaller circumferential growth stretches-specifically 1.12 ± 0.012 in the PA and 1.43 ± 0.071 in the AA at the adult stage. Overall, our results indicated that contact between the PA and AA resulted in increasing spatial heterogeneity in postnatal growth, with the PA demonstrating the greatest changes. Parametric studies using simplified geometric models of curved arteries during growth suggest that heterogeneous effective surface growth deformations must occur to account for the

  17. 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. PMID:22318227

  18. [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.

  19. 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

  20. 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

  1. Control of bacterial adhesion and growth on honeycomb-like patterned surfaces.

    PubMed

    Yang, Meng; Ding, Yonghui; Ge, Xiang; Leng, Yang

    2015-11-01

    It is a great challenge to construct a persistent bacteria-resistant surface even though it has been demonstrated that several surface features might be used to control bacterial behavior, including surface topography. In this study, we develop micro-scale honeycomb-like patterns of different sizes (0.5-10 μm) as well as a flat area as the control on a single platform to evaluate the bacterial adhesion and growth. Bacteria strains, Escherichia coli and Staphylococcus aureus with two distinct shapes (rod and sphere) are cultured on the platforms, with the patterned surface-up and surface-down in the culture medium. The results demonstrate that the 1 μm patterns remarkably reduce bacterial adhesion and growth while suppressing bacterial colonization when compared to the flat surface. The selective adhesion of the bacterial cells on the patterns reveals that the bacterial adhesion is cooperatively mediated by maximizing the cell-substrate contact area and minimizing the cell deformation, from a thermodynamic point of view. Moreover, study of bacterial behaviors on the surface-up vs. surface-down samples shows that gravity does not apparently affect the spatial distribution of the adherent cells although it indeed facilitates bacterial adhesion. Furthermore, the experimental results suggest that two major factors, i.e. the availability of energetically favorable adhesion sites and the physical confinements, contribute to the anti-bacterial nature of the honeycomb-like patterns.

  2. Control of bacterial adhesion and growth on honeycomb-like patterned surfaces.

    PubMed

    Yang, Meng; Ding, Yonghui; Ge, Xiang; Leng, Yang

    2015-11-01

    It is a great challenge to construct a persistent bacteria-resistant surface even though it has been demonstrated that several surface features might be used to control bacterial behavior, including surface topography. In this study, we develop micro-scale honeycomb-like patterns of different sizes (0.5-10 μm) as well as a flat area as the control on a single platform to evaluate the bacterial adhesion and growth. Bacteria strains, Escherichia coli and Staphylococcus aureus with two distinct shapes (rod and sphere) are cultured on the platforms, with the patterned surface-up and surface-down in the culture medium. The results demonstrate that the 1 μm patterns remarkably reduce bacterial adhesion and growth while suppressing bacterial colonization when compared to the flat surface. The selective adhesion of the bacterial cells on the patterns reveals that the bacterial adhesion is cooperatively mediated by maximizing the cell-substrate contact area and minimizing the cell deformation, from a thermodynamic point of view. Moreover, study of bacterial behaviors on the surface-up vs. surface-down samples shows that gravity does not apparently affect the spatial distribution of the adherent cells although it indeed facilitates bacterial adhesion. Furthermore, the experimental results suggest that two major factors, i.e. the availability of energetically favorable adhesion sites and the physical confinements, contribute to the anti-bacterial nature of the honeycomb-like patterns. PMID:26302067

  3. 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.

  4. 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.

  5. 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.

  6. 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".

  7. [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.

  8. 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

  9. Template-Assisted Direct Growth of 1 Td/in(2) Bit Patterned Media.

    PubMed

    Yang, En; Liu, Zuwei; Arora, Hitesh; Wu, Tsai-Wei; Ayanoor-Vitikkate, Vipin; Spoddig, Detlef; Bedau, Daniel; Grobis, Michael; Gurney, Bruce A; Albrecht, Thomas R; Terris, Bruce

    2016-07-13

    We present a method for growing bit patterned magnetic recording media using directed growth of sputtered granular perpendicular magnetic recording media. The grain nucleation is templated using an epitaxial seed layer, which contains Pt pillars separated by amorphous metal oxide. The scheme enables the creation of both templated data and servo regions suitable for high density hard disk drive operation. We illustrate the importance of using a process that is both topographically and chemically driven to achieve high quality media. PMID:27295317

  10. 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.

  11. Template-Assisted Direct Growth of 1 Td/in(2) Bit Patterned Media.

    PubMed

    Yang, En; Liu, Zuwei; Arora, Hitesh; Wu, Tsai-Wei; Ayanoor-Vitikkate, Vipin; Spoddig, Detlef; Bedau, Daniel; Grobis, Michael; Gurney, Bruce A; Albrecht, Thomas R; Terris, Bruce

    2016-07-13

    We present a method for growing bit patterned magnetic recording media using directed growth of sputtered granular perpendicular magnetic recording media. The grain nucleation is templated using an epitaxial seed layer, which contains Pt pillars separated by amorphous metal oxide. The scheme enables the creation of both templated data and servo regions suitable for high density hard disk drive operation. We illustrate the importance of using a process that is both topographically and chemically driven to achieve high quality media.

  12. Minibrain and Wings apart control organ growth and tissue patterning through down-regulation of Capicua.

    PubMed

    Yang, Liu; Paul, Sayantanee; Trieu, Kenneth G; Dent, Lucas G; Froldi, Francesca; Forés, Marta; Webster, Kaitlyn; Siegfried, Kellee R; Kondo, Shu; Harvey, Kieran; Cheng, Louise; Jiménez, Gerardo; Shvartsman, Stanislav Y; Veraksa, Alexey

    2016-09-20

    The transcriptional repressor Capicua (Cic) controls tissue patterning and restricts organ growth, and has been recently implicated in several cancers. Cic has emerged as a primary sensor of signaling downstream of the receptor tyrosine kinase (RTK)/extracellular signal-regulated kinase (ERK) pathway, but how Cic activity is regulated in different cellular contexts remains poorly understood. We found that the kinase Minibrain (Mnb, ortholog of mammalian DYRK1A), acting through the adaptor protein Wings apart (Wap), physically interacts with and phosphorylates the Cic protein. Mnb and Wap inhibit Cic function by limiting its transcriptional repressor activity. Down-regulation of Cic by Mnb/Wap is necessary for promoting the growth of multiple organs, including the wings, eyes, and the brain, and for proper tissue patterning in the wing. We have thus uncovered a previously unknown mechanism of down-regulation of Cic activity by Mnb and Wap, which operates independently from the ERK-mediated control of Cic. Therefore, Cic functions as an integrator of upstream signals that are essential for tissue patterning and organ growth. Finally, because DYRK1A and CIC exhibit, respectively, prooncogenic vs. tumor suppressor activities in human oligodendroglioma, our results raise the possibility that DYRK1A may also down-regulate CIC in human cells. PMID:27601662

  13. 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.

  14. 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.

  15. Digital transfer growth of patterned 2D metal chalcogenides by confined nanoparticle evaporation.

    PubMed

    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

    2014-11-25

    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 method 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 μm lateral sizes) of GaSe and MoSe2 are demonstrated, as well as continuous monolayer films through the deposition of additional precursor materials. This 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.

  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. PMID:25252643

  18. MET network in PubMed: a text-mined network visualization and curation system

    PubMed Central

    Dai, Hong-Jie; Su, Chu-Hsien; Lai, Po-Ting; Huang, Ming-Siang; Jonnagaddala, Jitendra; Rose Jue, Toni; Rao, Shruti; Chou, Hui-Jou; Milacic, Marija; Singh, Onkar; Syed-Abdul, Shabbir; Hsu, Wen-Lian

    2016-01-01

    Metastasis is the dissemination of a cancer/tumor from one organ to another, and it is the most dangerous stage during cancer progression, causing more than 90% of cancer deaths. Improving the understanding of the complicated cellular mechanisms underlying metastasis requires investigations of the signaling pathways. To this end, we developed a METastasis (MET) network visualization and curation tool to assist metastasis researchers retrieve network information of interest while browsing through the large volume of studies in PubMed. MET can recognize relations among genes, cancers, tissues and organs of metastasis mentioned in the literature through text-mining techniques, and then produce a visualization of all mined relations in a metastasis network. To facilitate the curation process, MET is developed as a browser extension that allows curators to review and edit concepts and relations related to metastasis directly in PubMed. PubMed users can also view the metastatic networks integrated from the large collection of research papers directly through MET. For the BioCreative 2015 interactive track (IAT), a curation task was proposed to curate metastatic networks among PubMed abstracts. Six curators participated in the proposed task and a post-IAT task, curating 963 unique metastatic relations from 174 PubMed abstracts using MET. Database URL: http://btm.tmu.edu.tw/metastasisway PMID:27242035

  19. MET network in PubMed: a text-mined network visualization and curation system.

    PubMed

    Dai, Hong-Jie; Su, Chu-Hsien; Lai, Po-Ting; Huang, Ming-Siang; Jonnagaddala, Jitendra; Rose Jue, Toni; Rao, Shruti; Chou, Hui-Jou; Milacic, Marija; Singh, Onkar; Syed-Abdul, Shabbir; Hsu, Wen-Lian

    2016-01-01

    Metastasis is the dissemination of a cancer/tumor from one organ to another, and it is the most dangerous stage during cancer progression, causing more than 90% of cancer deaths. Improving the understanding of the complicated cellular mechanisms underlying metastasis requires investigations of the signaling pathways. To this end, we developed a METastasis (MET) network visualization and curation tool to assist metastasis researchers retrieve network information of interest while browsing through the large volume of studies in PubMed. MET can recognize relations among genes, cancers, tissues and organs of metastasis mentioned in the literature through text-mining techniques, and then produce a visualization of all mined relations in a metastasis network. To facilitate the curation process, MET is developed as a browser extension that allows curators to review and edit concepts and relations related to metastasis directly in PubMed. PubMed users can also view the metastatic networks integrated from the large collection of research papers directly through MET. For the BioCreative 2015 interactive track (IAT), a curation task was proposed to curate metastatic networks among PubMed abstracts. Six curators participated in the proposed task and a post-IAT task, curating 963 unique metastatic relations from 174 PubMed abstracts using MET.Database URL: http://btm.tmu.edu.tw/metastasisway. PMID:27242035

  20. 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

  1. 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

  2. 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

  3. The use of PubMed/Medline in psychiatry. 3: Searching PubMed.

    PubMed

    Theander, Sten S

    2006-01-01

    This paper is the third in a series of three, intended as a tutorial in the use of PubMed/Medline for an inexperienced user. The papers have the following contents: I--a description of NLM, Medline, PubMed and the system of Medical Subject Headings (MeSH), which form the basis for the indexing of scientific articles, books and other items at NLM. II--A description and a tutorial of the PubMed search window. III--The present article deals mainly with the searching for references in PubMed. Ways of restricting and concentrating the search are presented, and exercises are proposed. A reader may also find guidance for a search for medical books in the NLM Catalog, and in the use of tools like Related Articles, Bookshelf, and Index. With eating disorders as an example, more information is presented on the use of MeSH terms.

  4. Growth patterns and morphology of fine roots of size-controlling and invigorating peach rootstocks.

    PubMed

    Basile, Boris; Bryla, David R; Salsman, Michelle L; Marsal, Jordi; Cirillo, Chiara; Johnson, R Scott; Dejong, Theodore M

    2007-02-01

    We compared growth patterns and morphology of fine roots of size-controlling and invigorating peach (Prunus persica (L.) Batsch) rootstocks. Peach trees were grafted on five rootstocks: a vigorous control (Nemaguard), three intermediate vigor rootstocks (K119-50, P30-135 and Hiawatha), and a semi-dwarfing rootstock (K146-43). Minirhizotron tubes were installed at the base of trees on each rootstock and root images captured with a minirhizotron digital camera system. Number, visible length, and diameter of new roots were recorded at fixed soil depths from April 19, 2000 to December 19, 2001. Root diameter, specific root length, root tissue density and root length density were also measured periodically for each rootstock on roots collected from in-growth cores. Rootstocks had similar seasonal patterns of new root production. Fine root production was lowest in winter and appeared to decline during the final stages of fruit growth. A rootstock with almond in its genetic background (K119-50) produced the greatest quantity of fine roots and had the greatest number of new roots below 69 cm, whereas there were no differences among the other four rootstocks in the total number of roots produced. Rootstock K146-43 had thicker fine roots than the other rootstocks. Independent of rootstock, fine roots produced during spring had greater specific root length than those produced later in the season. The seasonal pattern of fine root production did not appear to be associated with the previously reported effects of these dwarfing rootstocks on shoot growth and stem water potential early in the growing season.

  5. Water stress, photosynthesis and early growth patterns of cuttings of three Populus clones.

    PubMed

    Rhodenbaugh, E J; Pallardy, S G

    1993-10-01

    Photosynthetic attributes, leaf area and early root growth patterns were studied in three Populus clones to identify traits associated with superior growth potential on sites where water could be a limiting factor. It was found that early root growth and superior leaf area production were more closely related to growth potential than were photosynthetic capacity or carboxylation efficiency. A hybrid clone of Populus nigra var. charkowiensis (syn. P. nigra var. plantierensis) x P. nigra cv. 'Incrassata' (NE308) had more leaf area production and greater root system development in both wet and dry soil than did a P. trichocarpa clone (T6) and a P. balsamifera clone (B3). Despite greater above- and below-ground productivity, plants of clone NE308 had significantly lower photosynthetic capacity and carboxylation efficiency and a slightly higher CO(2) compensation point than plants of clones T6 and B3. Rapid early leaf and root growth appear to be key attributes associated with productivity in these clones regardless of soil water availability.

  6. 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.

  7. 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.

  8. Mojokerto revisited: evidence for an intermediate pattern of brain growth in Homo erectus.

    PubMed

    O'Connell, Caitlin A; DeSilva, Jeremy M

    2013-08-01

    Brain development in Homo erectus is a subject of great interest, and the infant calvaria from Mojokerto, Indonesia, has featured prominently in these debates. Some researchers have suggested that the pattern of brain development in H. erectus resembled that of non-human apes, while others argue for a more human-like growth pattern. In this study, we retested hypotheses regarding brain ontogeny in H. erectus using new methods (resampling), and data from additional H. erectus crania. Our results reveal that humans achieve 62% (±10%) and chimpanzees 80% (±9%) of their adult endocranial volume by 0.5-1.5 years of age. Using brain mass data, humans achieve on average 65% and chimpanzees 81% of adult size by 0.5-1.5 years. When compared with adult H. erectus crania (n = 9) from Indonesian sites greater than 1.2 million years old, Mojokerto had reached ∼70% of its adult cranial capacity. Mojokerto thus falls almost directly between the average growth in humans and chimpanzees, and well within the range of both. We therefore suggest that brain development in H. erectus cannot be dichotomized as either ape-like or human-like; it was H. erectus-like. These data indicate that H. erectus may have had a unique developmental pattern that should be considered as an important step along the continuum of brain ontogeny between apes and humans. PMID:23815827

  9. 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.

  10. 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.

  11. 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

  12. Nanoscale Growth Factor Patterns by Immobilization on a Heparin Mimicking Polymer

    PubMed Central

    Christman, Karen L.; Vázquez-Dorbatt, Vimary; Schopf, Eric; Kolodziej, Christopher M.; Li, Ronald C.; Broyer, Rebecca M.; Chen, Yong; Maynard, Heather D.

    2009-01-01

    In this study, electrostatic interactions between sulfonate groups of an immobilized polymer and the heparin binding domains of growth factors important in cell signaling were exploited to nanopattern the proteins. Poly(sodium 4-styrenesulfonate-co-poly(ethylene glycol) methacrylate) (pSS-co-pPEGMA) was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization using ethyl S-thiobenzoyl-2-thiopropionate as a chain transfer agent and 2,2′azoisobutyronitrile (AIBN) as the initiator. The resulting polymer (1) was characterized by 1H NMR, GPC, FT-IR, and UV-Vis and had a number average molecular weight (Mn) of 24,000 and a polydispersity index (PDI) of 1.17. The dithioester end group of 1 was reduced to the thiol, and the polymer subsequently immobilized on a gold substrate. Binding of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) to the polymer via the heparin binding domains was then confirmed by surface plasmon resonance (SPR). The interactions were stable at physiological salt concentrations. Polymer 1 was cross-linked onto silicon wafers using an electron beam writer forming micron- and nano- patterns. Resolutions of 100 nm and arbitrary nanoscale features such as concentric circles and contiguous squares and triangles were achieved. Fluorescence microscopy confirmed that bFGF and VEGF were subsequently immobilized to the polymer micro- and nano- patterns. PMID:19554729

  13. Evolution of Surface Morphology of Patterned GaAs(100) during Molecular Beam Epitaxial Growth

    NASA Astrophysics Data System (ADS)

    Kan, Hung-Chih; Shah, Sonam; Tadayyon-Eslami, Tabassom; Phaneuf, Raymond

    2003-03-01

    We report the results of an investigation of the evolution of the surface morphology during molecular beam epitaxial growth on a patterned GaAs(100) surface. The initial GaAs(100) surfaces were patterned lithographically with arrays of cylindrical pits whose diameters and center-to-center distances are varied in a combinatorial manner. Using atomic force microscopy (AFM), we characterized the evolution of the corrugation throughout the growth. We compare the measured height profiles with simulations from various continuum models[1]. This comparison allows us to discriminate between various continuum modes of growth. * Work supported by the Minta-Martin Foundation, the Laboratory for Physical Sciences, and an NSF-MRSEC, DMR 00-8008. Reference 1 Mehran Kardar, Giorgio Parisi, and Yi-Cheng Zhang, Physical Review Letters 56 (9), 889 (1986); Tao Sun, Hong Guo, and Martin Grant, Physical Review A 40 (11), 6763 (1989); Z.-W. Lai and S. Das Sarma, Physical Review Letters 66 (18), 2348 (1991); M. D. Johnson, C. Orme, A. W. Hunt et al., Physical Review Letters 72 (1), 116 (1994).

  14. 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.

  15. 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

  16. Multi-lingual search engine to access PubMed monolingual subsets: a feasibility study.

    PubMed

    Darmoni, Stéfan J; Soualmia, Lina F; Griffon, Nicolas; Grosjean, Julien; Kerdelhué, Gaétan; Kergourlay, Ivan; Dahamna, Badisse

    2013-01-01

    PubMed contains many articles in languages other than English but it is difficult to find them using the English version of the Medical Subject Headings (MeSH) Thesaurus. The aim of this work is to propose a tool allowing access to a PubMed subset in one language, and to evaluate its performance. Translations of MeSH were enriched and gathered in the information system. PubMed subsets in main European languages were also added in our database, using a dedicated parser. The CISMeF generic semantic search engine was evaluated on the response time for simple queries. MeSH descriptors are currently available in 11 languages in the information system. All the 654,000 PubMed citations in French were integrated into CISMeF database. None of the response times exceed the threshold defined for usability (2 seconds). It is now possible to freely access biomedical literature in French using a tool in French; health professionals and lay people with a low English language may find it useful. It will be expended to several European languages: German, Spanish, Norwegian and Portuguese.

  17. Comparison of PubMed, Scopus, Web of Science, and Google Scholar: strengths and weaknesses.

    PubMed

    Falagas, Matthew E; Pitsouni, Eleni I; Malietzis, George A; Pappas, Georgios

    2008-02-01

    The evolution of the electronic age has led to the development of numerous medical databases on the World Wide Web, offering search facilities on a particular subject and the ability to perform citation analysis. We compared the content coverage and practical utility of PubMed, Scopus, Web of Science, and Google Scholar. The official Web pages of the databases were used to extract information on the range of journals covered, search facilities and restrictions, and update frequency. We used the example of a keyword search to evaluate the usefulness of these databases in biomedical information retrieval and a specific published article to evaluate their utility in performing citation analysis. All databases were practical in use and offered numerous search facilities. PubMed and Google Scholar are accessed for free. The keyword search with PubMed offers optimal update frequency and includes online early articles; other databases can rate articles by number of citations, as an index of importance. For citation analysis, Scopus offers about 20% more coverage than Web of Science, whereas Google Scholar offers results of inconsistent accuracy. PubMed remains an optimal tool in biomedical electronic research. Scopus covers a wider journal range, of help both in keyword searching and citation analysis, but it is currently limited to recent articles (published after 1995) compared with Web of Science. Google Scholar, as for the Web in general, can help in the retrieval of even the most obscure information but its use is marred by inadequate, less often updated, citation information.

  18. Racial Differences in Growth Patterns of Children Assessed on the Basis of Bone Age1

    PubMed Central

    Zhang, Aifeng; Sayre, James W.; Vachon, Linda; Liu, Brent J.; Huang, H. K.

    2009-01-01

    Purpose: To collect up-to-date data in healthy children to create a digital hand atlas (DHA) that can be used to evaluate, on the basis of the Greulich and Pyle atlas method, racial differences in skeletal growth patterns of Asian, African American, white, and Hispanic children in the United States. Materials and Methods: This retrospective study was HIPAA compliant and approved by the institutional review board. Informed consent was obtained from all subjects or their guardians. From May 1997 to March 2008, a DHA containing 1390 hand and wrist radiographs obtained in male and female Asian, African American, white, and Hispanic children with normal skeletal development was developed. The age of subjects ranged from 1 day to 18 years. Each image was read by two pediatric radiologists working independently and without knowledge of the subject's chronologic age, and evaluation was based on their experience with the Greulich and Pyle atlas. Statistical analyses were performed with the paired-samples t test and analysis of variance to study racial differences in growth patterns. P ≤ .05 indicated a significant difference. Results: Bone age (P ≤ .05) was significantly overestimated in Asian and Hispanic children. These children appear to mature sooner than their African American and white peers. This was seen in both male and female subjects, especially in girls aged 10–13 years and boys aged 11–15 years. Conclusion: Ethnic and racial differences in growth patterns exist at certain ages; however, the Greulich and Pyle atlas does not recognize this fact. Assessment of bone age in children with use of the Greulich and Pyle atlas can be improved by considering the subject's ethnicity. © RSNA, 2008 PMID:18955510

  19. 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. PMID:27441921

  20. 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.

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

    PubMed Central

    2012-01-01

    Background 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. Methods 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. Results 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. Conclusion 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

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    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.

  4. 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

  5. Mentoring programs for medical students - a review of the PubMed literature 2000 - 2008

    PubMed Central

    2010-01-01

    Background Although mentoring is acknowledged as a key to successful and satisfying careers in medicine, formal mentoring programs for medical students are lacking in most countries. Within the framework of planning a mentoring program for medical students at Zurich University, an investigation was carried out into what types of programs exist, what the objectives pursued by such programs are, and what effects are reported. Methods A PubMed literature search was conducted for 2000 - 2008 using the following keywords or their combinations: mentoring, mentoring program, medical student, mentor, mentee, protégé, mentorship. Although a total of 438 publications were identified, only 25 papers met the selection criteria for structured programs and student mentoring surveys. Results The mentoring programs reported in 14 papers aim to provide career counseling, develop professionalism, increase students' interest in research, and support them in their personal growth. There are both one-to-one and group mentorships, established in the first two years of medical school and continuing through graduation. The personal student-faculty relationship is important in that it helps students to feel that they are benefiting from individual advice and encourages them to give more thought to their career choices. Other benefits are an increase in research productivity and improved medical school performance in general. Mentored students also rate their overall well-being as higher. - The 11 surveys address the requirements for being an effective mentor as well as a successful mentee. A mentor should empower and encourage the mentee, be a role model, build a professional network, and assist in the mentee's personal development. A mentee should set agendas, follow through, accept criticism, and be able to assess performance and the benefits derived from the mentoring relationship. Conclusion Mentoring is obviously an important career advancement tool for medical students. In Europe

  6. 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

  7. The pattern of histogenesis and growth of tooth plates in larval stages of extant lungfish.

    PubMed

    Smith, M M

    1985-06-01

    Comparison of new data obtained in this study on Protopterus aethiopicus with that published on Protopterus aethiopicus and Neoceratodus forsteri has confirmed the suggestion that the pattern of histogenesis of tooth plates in the early larval stages is very similar in the two genera. These similarities are more apparent both when a common terminology is adopted, based on a topogenic classification, and when the fundamental assumption is made that a single morphogenetic system operates for all odontodes. The model to explain the structure of all vertebrate dentitions with separate teeth in single or multiple tooth rows has been found to apply to dipnoan dentitions with fused teeth in a composite tooth plate. In this model, the epithelial invagination surrounding the margins of the tooth plate represents the dental lamina and, where this is in contact with mesenchymal cells, cell clusters (protogerms) arise. From these protogerms new odontodes (teeth) may develop if factors to inhibit differentiation are not present. Sites for initiation of odontodes become restricted to the labial margins of existing ridges on the tooth plate. Experimental studies on mammalian tooth germs are discussed and a model proposed for control of odontogenesis and histogenesis in dipnoan dentitions. Patterns of growth of hypermineralised petrodentine have been analysed and shown to depend initially on the arrangement of odontodes, and subsequently upon the ability of special cells in the pulp to generate new and wider layers of petrodentine. The initial pattern of petrodentine depends upon the position of odontodes in the forming ridges of the tooth plate. Subsequent patterns of petrodentine depend upon the extent of replacement growth beneath the tritural surface. Specialised cells, petroblasts, secrete the petrodentine within a shell of dentine. These cells differentiate from cells of the dental papilla after odontoblasts have begun to form dentine. They are regarded as a unique type of

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

    DOE PAGESBeta

    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; et al

    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

  9. 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.

  10. Impact of PubMed search filters on the retrieval of evidence by physicians

    PubMed Central

    Shariff, Salimah Z.; Sontrop, Jessica M.; Haynes, R. Brian; Iansavichus, Arthur V.; McKibbon, K. Ann; Wilczynski, Nancy L.; Weir, Matthew A.; Speechley, Mark R.; Thind, Amardeep; Garg, Amit X.

    2012-01-01

    Background: Physicians face challenges when searching PubMed for research evidence, and they may miss relevant articles while retrieving too many nonrelevant articles. We investigated whether the use of search filters in PubMed improves searching by physicians. Methods: We asked a random sample of Canadian nephrologists to answer unique clinical questions derived from 100 systematic reviews of renal therapy. Physicians provided the search terms that they would type into PubMed to locate articles to answer these questions. We entered the physician-provided search terms into PubMed and applied two types of search filters alone or in combination: a methods-based filter designed to identify high-quality studies about treatment (clinical queries “therapy”) and a topic-based filter designed to identify studies with renal content. We evaluated the comprehensiveness (proportion of relevant articles found) and efficiency (ratio of relevant to nonrelevant articles) of the filtered and nonfiltered searches. Primary studies included in the systematic reviews served as the reference standard for relevant articles. Results: The average physician-provided search terms retrieved 46% of the relevant articles, while 6% of the retrieved articles were nonrelevant (the ratio of relevant to nonrelevant articles was 1:16). The use of both filters together produced a marked improvement in efficiency, resulting in a ratio of relevant to nonrelevant articles of 1:5 (16 percentage point improvement; 99% confidence interval 9% to 22%; p < 0.003) with no substantive change in comprehensiveness (44% of relevant articles found; p = 0.55). Interpretation: The use of PubMed search filters improves the efficiency of physician searches. Improved search performance may enhance the transfer of research into practice and improve patient care. PMID:22249990

  11. 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.

  12. 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

  13. Modeling Microbial Growth Dynamics, Patterns, and Coexistence on Partially Saturated Rough Surfaces

    NASA Astrophysics Data System (ADS)

    Long, T.; Or, D.

    2005-12-01

    A new modeling tool was developed to study the impact of variations in matric potential on aquatic pathways and substrate diffusion, and on microbial growth and movement on unsaturated rough surfaces. The modeling domain is composed of prescribed distributions of conical pits (sites) connected by prismatic channels (bonds) representing rough surfaces of soils or rocks. The well-defined geometry facilitates exact description of aqueous phase distribution within the roughness for a given matric potential. Microbial growth within the resulting highly variable diffusion network architectures (vary with matric potential) and interactions with nutrient diffusion patterns are simulated by coupling Reaction-Diffusion Method (RDM) and the Active Walker Method (AWM). Simulation results show direct impact of wetness conditions (matric potential values) on microbial growth rates and expansion patters for the same surface roughness. In addition to modification of mean diffusion rates for drier or wetter conditions, the network connectivity may induce significant changes in spatial patters of microbial growth. Impact of these changes on coexistence of two competing microbial species will be discussed.

  14. 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.

  15. Architecture and growth patterns of last deglacial reefs. IODP Expedition #310, Tahiti (French Polynesia).

    NASA Astrophysics Data System (ADS)

    Seard, C.; Camoin, G.; Yokoyama, Y.; Durand, N.; Matsuzaki, H.; Deschamps, P.; Bard, E.

    2009-04-01

    The study of coral reef systems that developed during the last deglaciation (23,000-6,000 cal. yr BP) is of pivotal interest both for the reconstruction of climatic and environmental changes, and the evaluation of the impact of those combined changes on reef accretion, growth modes and architecture. However, those features have been poorly documented because they are mostly stored on modern fore-reef slopes, at depths greater than 100 m. The present study, based on the sedimentological and chronological analysis (14C AMS dating) of drill cores carried out on the successive terraces occurring on the modern reef slopes from Tahiti (IODP Expedition #310 « Tahiti Sea Level »), provides a comprehensive data base to investigate the microbialite growth patterns (e.g. growth rates and habitats), to analyze their roles in the reef frameworks, to reconstruct the evolution of the reef framework architecture and to better constrain the changing environmental conditions through time. The last deglacial reefs from Tahiti are composed of two distinctive biological communities which were characterized by a similar scenario of development throughout the sequence, involving a diachronous development and a lack of direct competition. The coralgal communities composed of seven assemblages characterized by various growth forms (branching, robust branching, massive, tabular and encrusting) formed the initial frameworks, while microbialites developed in the primary cavities of those frameworks, a few meters below the living reef surface, where they heavily encrusted the coralgal assemblages. The offset between the growth of coral assemblages and the development of microbialite crusts ranges from 300 to 700 years. The development of microbial crusts was controlled by the volume and the shape of the primary cavities of the initial reef frameworks determined by the morphology and the packing of coral colonies. The highest microbialite development occurred in frameworks dominated by

  16. 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

  17. 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

  18. Length-scale mediated adhesion and directed growth of neural cells by surface-patterned poly(ethylene glycol) hydrogels.

    PubMed

    Krsko, Peter; McCann, Thomas E; Thach, Thu-Trang; Laabs, Tracy L; Geller, Herbert M; Libera, Matthew R

    2009-02-01

    We engineered surfaces that permit the adhesion and directed growth of neuronal cell processes but that prevent the adhesion of astrocytes. This effect was achieved based on the spatial distribution of sub-micron-sized cell-repulsive poly(ethylene glycol) [PEG] hydrogels patterned on an otherwise cell-adhesive substrate. Patterns were identified that promoted cellular responses ranging from complete non-attachment, selective attachment, and directed growth at both cellular and subcellular length scales. At the highest patterning density where the individual hydrogels almost overlapped, there was no cellular adhesion. As the spacing between individual hydrogels was increased, patterns were identified where neurites could grow on the adhesive surface between hydrogels while astrocytes were unable to adhere. Patterns such as lines or arrays were identified that could direct the growth of these subcellular neuronal processes. At higher hydrogel spacings, both neurons and astrocytes adhered and grew in a manner approaching that of unpatterned control surfaces. Patterned lines could once again direct growth at cellular length scales. Significantly, we have demonstrated that the patterning of sub-micron/nano scale cell-repulsive features at microscale lengths on an otherwise cell-adhesive surface can differently control the adhesion and growth of cells and cell processes based on the difference in their characteristic sizes. This concept could potentially be applied to an implantable nerve-guidance device that would selectively enable regrowing axons to bridge a spinal-cord injury without interference from the glial scar.

  19. Length-Scale Mediated Adhesion and Directed Growth of Neural Cells by Surface-Patterned Poly(ethylene glycol) Hydrogels

    PubMed Central

    Krsko, Peter; McCann, Thomas; Thach, Thu-Trang; Laabs, Tracy; Geller, Herbert M.; Libera, Matthew

    2012-01-01

    We engineered surfaces that permit the adhesion and directed growth of neuronal cell processes – axons – but that prevent the adhesion of astrocytes. This effect was achieved based on the spatial distribution of cell-repulsive poly(ethylene glycol) [PEG] nanohydrogels patterned on an otherwise cell-adhesive substrate. Patterns were identified that promoted cellular responses ranging from complete non-attachment, selective attachment, and directed growth at both cellular and subcellular length scales. At the highest patterning density where the individual nanohydrogels almost overlapped, there was no cellular adhesion. As the spacing between individual nanohydrogels was increased, patterns were identified where axons could grow on the adhesive surface between nanohydrogels while astrocytes were unable to adhere. Patterns such as lines or arrays were identified that could direct the growth of these subcellular neuronal processes. At higher nanohydrogel spacings, both neurons and astrocytes adhered and grew in a manner approaching that of unpatterned control surfaces. Patterned lines could once again direct growth at cellular length scales. Significantly, we have demonstrated that the patterning of nanoscale cell-repulsive features at microscale lengths on an otherwise cell-adhesive surface can differently control the adhesion and growth of cells and cell processes based on the difference in their characteristic sizes. This concept could potentially be applied to an implantable nerve-guidance device that would selectively enable regrowing axons to bridge a spinal-cord injury without interference from the glial scar. PMID:19026443

  20. Regeneration patterns of northern white cedar, an old-growth forest dominant

    USGS Publications Warehouse

    Scott, Michael L.; Murphy, Peter G.

    1987-01-01

    Regeneration of Thuja occidentalis L. was examined in an old-growth dune forest on South Manitou Island, Michigan. To estimate the current status of cedar regeneration, we determined size structure of seedlings and stems and analyzed present patterns of establishment and persistence relative to substrate type. There has been a shift in the pattern of cedar establishment from soil to log substrates. While 97% of all stems ≥15 cm dbh are associated with a soil substrate, 81% of stems ≥2.5cm-25 cm tall. There was no significant relationship between the state of log decay and the density of seedlings >25 cm in height, indicating that long-term survival is not dependent on the degree of log decomposition. However, survival on logs is associated with canopy openings. Seedlings >25 cm tall were associated with gaps, and 78% of cedar stems (≥2.5 cm dbh) on logs were associated with a single windthrow gap. Thus, current cedar regeneration in this old-growth forest depends on logs and the canopy openings associated with them.

  1. 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…

  2. 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…

  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. Origin of craniopharyngiomas: implications for growth pattern, clinical characteristics, and outcomes of tumor recurrence.

    PubMed

    Bao, Yun; Pan, Jun; Qi, Song-Tao; Lu, Yun-Tao; Peng, Jun-Xiang

    2016-07-01

    OBJECT Craniopharyngiomas are associated with a high rate of recurrence. The surgical management of recurrent lesions has been among the most challenging neurosurgical procedures because of the craniopharyngioma's complex topographical relationship with surrounding structures. The aim of this study was to define the determinative role of the site of origin on the growth pattern and clinical features of recurrent craniopharyngiomas. METHODS The authors performed a retrospective analysis of 52 patients who had undergone uniform treatment by a single surgeon. For each patient, data concerning symptoms and signs, imaging features, hypothalamic-pituitary function, and recurrence-free survival rate were collected. RESULTS For children, delayed puberty was more frequent in the group with Type I (infradiaphragmatic) craniopharyngioma than in the group with Type TS (tuberoinfundibular and suprasellar extraventricular) lesions (p < 0.05). For adults, blindness was more frequent in the Type I group than in the Type TS group (p < 0.05). Nausea or vomiting, delayed puberty, and growth retardation were more frequent in children than in adults (p < 0.05). Overall clinical outcome was good in 48.07% of the patients and poor in 51.92%. Patients with Type TS recurrent tumors had significantly worse functional outcomes and hypothalamic function than patients with the Type I recurrent tumors but better pituitary function especially in children. CONCLUSIONS The origin of recurrent craniopharyngiomas significantly affected the symptoms, signs, functional outcomes, and hypothalamic-pituitary functions of patients undergoing repeated surgery. Differences in tumor growth patterns and site of origin should be considered when one is comparing outcomes and survival across treatment paradigms in patients with recurrent craniopharyngiomas. PMID:26654183

  6. 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

  7. 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.

  8. PubMedAlertMe--standalone Windows-based PubMed SDI software application.

    PubMed

    Ma'ayan, Avi

    2008-05-01

    PubMedAlertMe is a Windows-based software system for automatically receiving e-mail alert messages about recent publications listed on PubMed. The e-mail messages contain links to newly available abstracts listed on PubMed describing publications that were selectively returned from a specified list of queries. Links are also provided to directly export citations to EndNote, and links are provided to directly forward articles to colleagues. The program is standalone. Thus, it does not require a remote mail server or user registration. PubMedAlertMe is free software, and can be downloaded from: http://amp.pharm.mssm.edu/PubMedAlertMe/PubMedAlertMe_setup.zip.

  9. Teaching PubMed in cyberspace: the development of a self-learning package.

    PubMed

    King, Samuel; Kaplan, Richard; MacDonald, Kathleen

    2008-01-01

    This article discusses the development of a series of online modules for learning the PubMed version of MEDLINE. Funded by a National Library of Medicine grant and targeted initially to physician assistants practicing in New Hampshire, the project is approved for CE credit nationally by the American Association of Physician Assistants. The development of the project is described, the tutorial modules are reviewed, and issues encountered with technology and human factors are discussed and evaluated. PMID:19042708

  10. Precision and negative predictive value of links between ClinicalTrials.gov and PubMed.

    PubMed

    Huser, Vojtech; Cimino, James J

    2012-01-01

    One of the goals of translational science is to shorten the time from discovery to clinical use. Clinical trial registries were established to increase transparency in completed and ongoing clinical trials, and they support linking trials with resulting publications. We set out to investigate precision and negative predictive value (NPV) of links between ClinicalTrials.gov (CT.gov) and PubMed. CT.gov has been established to increase transparency in clinical trials and the link to PubMed is crucial for supporting a number of important functions, including ascertaining publication bias. We drew a random sample of trials downloaded from CT.gov and performed manual review of retrieved publications. We characterize two types of links between trials and publications (NCT-link originating from MEDLINE and PMID-link originating from CT.gov).The link precision is different based on type (NCT-link: 100%; PMID-link: 63% to 96%). In trials with no linked publication, we were able to find publications 44% of the time (NPV=56%) by searching PubMed. This low NPV shows that there are potentially numerous publications that should have been formally linked with the trials. Our results indicate that existing trial registry and publisher policies may not be fully enforced. We suggest some automated methods for improving link quality.

  11. The Relation between Iranian Medical Science Research in PubMed and Burden of Disease

    PubMed Central

    Foroughi, Zahra; Siamian, Hasan; Alizadeh-Navaei, Reza; Davodi, Ali

    2016-01-01

    Introduction: Scientific productions have been accelerated in Iran in past decades but its association with health problems and disease burden is doubtful. The aim of this study is assessment of the relationship between scientific productions with disease burden in Iran in PubMed dataset during 2010 to 2014. Method: The study was performed with the library method. Data Gathered using Scientometrics indicators and direct observation. The current research includes all articles written by Iranian researchers during 2010 to 2014 which were published in PubMed–indexed journals. The search was performed using keywords included road accident, ischaemic heart diseases, major depression disorders and cerebral vascular diseases. Results: In total 910 articles had been published PubMed -indexed journals. Among them Substance-Related Disorders and Accidents, Traffic had the highest (263 records) and lowest (94 records) records respectively. There was not a direct correlation between Years of Life Lost, Years Lost due to Disability and mortality rate with scientific productions. Conclusions: our results showed Iranian scientific productions in PubMed data set are not related to disease burden however they are not related to high mortality diseases. PMID:27708491

  12. Canine splenic haemangiosarcoma: influence of metastases, chemotherapy and growth pattern on post-splenectomy survival and expression of angiogenic factors.

    PubMed

    Göritz, M; Müller, K; Krastel, D; Staudacher, G; Schmidt, P; Kühn, M; Nickel, R; Schoon, H-A

    2013-07-01

    Splenic haemangiosarcomas (HSAs) from 122 dogs were characterized and classified according to their patterns of growth, survival time post splenectomy, metastases and chemotherapy. The most common pattern of growth was a mixture of cavernous, capillary and solid tumour tissue. Survival time post splenectomy was independent of the growth pattern; however, it was influenced by chemotherapy and metastases. Immunohistochemical assessment of the expression of angiogenic factors (fetal liver kinase-1, angiopoietin-2, angiopoietin receptor-2 and vascular endothelial growth factor A) and conventional endothelial markers (CD31, factor VIII-related antigen) revealed variable expression, particularly in undifferentiated HSAs. Therefore, a combination of endothelial markers should be used to confirm the endothelial origin of splenic tumours. PMID:23276383

  13. 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.

  14. 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. PMID:24442595

  15. NEMO: Extraction and normalization of organization names from PubMed affiliation strings

    PubMed Central

    Jonnalagadda, Siddhartha; Topham, Philip

    2010-01-01

    Background. We are witnessing an exponential increase in biomedical research citations in PubMed. However, translating biomedical discoveries into practical treatments is estimated to take around 17 years, according to the 2000 Yearbook of Medical Informatics, and much information is lost during this transition. Pharmaceutical companies spend huge sums to identify opinion leaders and centers of excellence. Conventional methods such as literature search, survey, observation, self-identification, expert opinion, and sociometry not only need much human effort, but are also noncomprehensive. Such huge delays and costs can be reduced by “connecting those who produce the knowledge with those who apply it”. A humble step in this direction is large scale discovery of persons and organizations involved in specific areas of research. This can be achieved by automatically extracting and disambiguating author names and affiliation strings retrieved through Medical Subject Heading (MeSH) terms and other keywords associated with articles in PubMed. In this study, we propose NEMO (Normalization Engine for Matching Organizations), a system for extracting organization names from the affiliation strings provided in PubMed abstracts, building a thesaurus (list of synonyms) of organization names, and subsequently normalizing them to a canonical organization name using the thesaurus. Results: We used a parsing process that involves multi-layered rule matching with multiple dictionaries. The normalization process involves clustering based on weighted local sequence alignment metrics to address synonymy at word level, and local learning based on finding connected components to address synonymy. The graphical user interface and java client library of NEMO are available at http://lnxnemo.sourceforge.net . Conclusion: NEMO is developed to associate each biomedical paper and its authors with a unique organization name and the geopolitical location of that organization. This system

  16. Global-scale pattern of peatland Sphagnum growth driven by photosynthetically active radiation and growing season length

    NASA Astrophysics Data System (ADS)

    Loisel, J.; Gallego-Sala, A. V.; Yu, Z.

    2012-02-01

    High-latitude peatlands contain about one third of the world's soil organic carbon, most of which is derived from partly decomposed Sphagnum (peat moss) plants. We conducted a meta-analysis based on a global dataset of Sphagnum growth measurements collected from published literature to investigate the effects of bioclimatic variables on Sphagnum growth. Analysis of variance and general linear models were used to relate Sphagnum magellanicum and S. fuscum growth rates to photosynthetically active radiation integrated over the growing season (PAR0) and a moisture index. We found that PAR0 was the main predictor of Sphagnum growth for the global dataset, and effective moisture was only correlated with moss growth at continental sites. The strong correlation between Sphagnum growth and PAR0 suggests the existence of a global pattern of growth, with slow rates under cool climate and short growing seasons, highlighting the important role of temperature and growing season length in explaining peatland biomass production. Large-scale patterns of cloudiness during the growing season might also limit moss growth. Although considerable uncertainty remains over the carbon balance of peatlands under a changing climate, our results suggest that increasing PAR0 as a result of global warming and lengthening growing seasons could promote Sphagnum growth. Assuming that production and decomposition have the same sensitivity to temperature, this enhanced growth could lead to greater peat-carbon sequestration, inducing a negative feedback to climate change.

  17. Global-scale pattern of peatland Sphagnum growth driven by photosynthetically active radiation and growing season length

    NASA Astrophysics Data System (ADS)

    Loisel, J.; Gallego-Sala, A. V.; Yu, Z.

    2012-07-01

    High-latitude peatlands contain about one third of the world's soil organic carbon, most of which is derived from partly decomposed Sphagnum (peat moss) plants. We conducted a meta-analysis based on a global data set of Sphagnum growth measurements collected from published literature to investigate the effects of bioclimatic variables on Sphagnum growth. Analysis of variance and general linear models were used to relate Sphagnum magellanicum and S. fuscum growth rates to photosynthetically active radiation integrated over the growing season (PAR0) and a moisture index. We found that PAR0 was the main predictor of Sphagnum growth for the global data set, and effective moisture was only correlated with moss growth at continental sites. The strong correlation between Sphagnum growth and PAR0 suggests the existence of a global pattern of growth, with slow rates under cool climate and short growing seasons, highlighting the important role of growing season length in explaining peatland biomass production. Large-scale patterns of cloudiness during the growing season might also limit moss growth. Although considerable uncertainty remains over the carbon balance of peatlands under a changing climate, our results suggest that increasing PAR0 as a result of global warming and lengthening growing seasons, without major change in cloudiness, could promote Sphagnum growth. Assuming that production and decomposition have the same sensitivity to temperature, this enhanced growth could lead to greater peat-carbon sequestration, inducing a negative feedback to climate change.

  18. Growth and alignment of thin film organic single crystals from dewetting patterns.

    PubMed

    Tisserant, Jean-Nicolas; Wicht, Gaëtan; Göbel, Ole F; Bocek, Eva; Bona, Gian-Luca; Geiger, Thomas; Hany, Roland; Mezzenga, Raffaele; Partel, Stefan; Schmid, Peter; Schweizer, Wolfhard Bernd; Heier, Jakob

    2013-06-25

    Studying and understanding the conditions under which organic semiconductors can be engineered to form aligned single crystals in thin films is of primary importance owing to their unique orientation-dependent optoelectronic properties. Efforts to reach this goal by self-assembly from solution-processed films have been rewarded only with limited success. In this article we present a new method to grow single crystalline thin films via solvent annealing. We identify solvate crystal growth in combination with a specific film dewetting morphology as key to successful fabrication of single crystals. Furthermore, these 2D single crystals can align on chemically patterned substrates to minimize their interfacial energy. We explore in situ the conditions for crystal formation and alignment.

  19. Crystal growth in a channel: Pulsating fingers, merry-go-round patterns, and seesaw dynamics

    NASA Astrophysics Data System (ADS)

    Debierre, Jean-Marc; Guérin, Rahma; Kassner, Klaus

    2013-10-01

    We perform phase-field simulations of unsteady crystal growth in a three-dimensional capillary. Motivated by the appearance of chirality-symmetry breaking periodic states in our preceding study, we here focus on more general dynamic states. Most of these are obtained in the limit of isotropic surface tension, but we test genericity by looking at a few cases with weak anisotropy. Whereas steady states are similar for all channel shapes studied so far, including channels with circular, hexagonal, quadratic, and triangular cross sections, there is a stronger dependence on the cross section for time-dependent states. Various oscillatory modes are identified and discussed, including rotating and swinging patterns as well as pulsating modes containing one, two, and four fingers, respectively.

  20. 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.

  1. Low-dose total body irradiation versus combination chemotherapy for lymphomas with follicular growth pattern.

    PubMed

    Meerwaldt, J H; Carde, P; Burgers, J M; Monconduit, M; Thomas, J; Somers, R; Sizoo, W; Glabbeke, M V; Duez, N; de Wolf-Peeters, C

    1991-10-01

    The treatment of Non-Hodgkin's lymphomas with follicular growth pattern and advanced stage of disease remains controversial. Treatments varying from no initial treatment up to aggressive combination chemotherapy have been advocated. The EORTC Lymphoma Cooperative Group has performed a randomized prospective trial comparing short duration low dose total body irradiation (TBI) vs combination chemotherapy (CHVmP) + consolidation radiotherapy. Ninety-three patients were entered; of 84 evaluable patients, 44 received TBI and 40 CHVmP. Complete remission (CR) rates were 36%--TBI and 55%--CHVmP, but overall response rates were identical, 76 versus 69%. No significant difference in freedom from progression or survival was observed. No unexpected toxicity was seen. Although numbers are small, we cannot conclude that aggressive combination chemo-radiotherapy resulted in a better survival. Our analysis confirms that there is a constant risk of relapse. Other approaches should be explored if survival benefit is the ultimate goal in treatment of this patient population.

  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. 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.

  4. 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

  5. Expression Patterns of CREBs in Oocyte Growth and Maturation of Fish.

    PubMed

    Senthilkumaran, Balasubramanian; Sreenivasulu, Gunti; 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

  6. Wnt5a regulates growth, patterning, and odontoblast differentiation of developing mouse tooth.

    PubMed

    Lin, Minkui; Li, Lu; Liu, Chao; Liu, Hongbing; He, Fenglei; Yan, Fuhua; Zhang, Yanding; Chen, Yiping

    2011-02-01

    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.

  7. Simultaneous inference of selection and population growth from patterns of variation in the human genome

    PubMed Central

    Williamson, Scott H.; Hernandez, Ryan; Fledel-Alon, Adi; Zhu, Lan; Nielsen, Rasmus; Bustamante, Carlos D.

    2005-01-01

    Natural selection and demographic forces can have similar effects on patterns of DNA polymorphism. Therefore, to infer selection from samples of DNA sequences, one must simultaneously account for demographic effects. Here we take a model-based approach to this problem by developing predictions for patterns of polymorphism in the presence of both population size change and natural selection. If data are available from different functional classes of variation, and a priori information suggests that mutations in one of those classes are selectively neutral, then the putatively neutral class can be used to infer demographic parameters, and inferences regarding selection on other classes can be performed given demographic parameter estimates. This procedure is more robust to assumptions regarding the true underlying demography than previous approaches to detecting and analyzing selection. We apply this method to a large polymorphism data set from 301 human genes and find (i) widespread negative selection acting on standing nonsynonymous variation, (ii) that the fitness effects of nonsynonymous mutations are well predicted by several measures of amino acid exchangeability, especially site-specific methods, and (iii) strong evidence for very recent population growth. PMID:15905331

  8. Pattern Growth and Field Emission Characteristics of Flower-Like RuO2 Nanostructures

    NASA Astrophysics Data System (ADS)

    Lee, Kuei-Yi; Chen, Ching-An; Lian, Huan-Bin; Chen, Yi-Min; Huang, Ying-Sheng; Keiser, Gerd

    2010-10-01

    A flower-like RuO2 nanostructure was selectively synthesized on a Si substrate by metal organic chemical vapor deposition (MOCVD). Bis(ethylcyclopentadienyl) ruthenium(II), Ru[(C2H5)C5H4]2, was shower sprayed onto the Si substrate with oxygen gas. Prior to the growth of the flower-like RuO2 nanostructure, patterns of Al and Fe films were deposited on the Si substrate by photolithography and electron beam (e-beam) evaporation deposition. The synthesized flower-like RuO2 nanostructures were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD), and micro-Raman spectroscopy. The results indicated that the flower-like nanostructures were RuO2 rutile structures with high crystallinity. For the particular synthesized morphology and design pattern, the current density and long-term stability characteristics of electron field-emission characteristics demonstrated that the flower-like RuO2 nanostructure has the potential to be used in a practical field-emission display.

  9. 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.

  10. Extracellular-controlled breast cancer cell formation and growth using non-UV patterned hydrogels via optically-induced electrokinetics.

    PubMed

    Liu, Na; Liang, Wenfeng; Liu, Lianqing; Wang, Yuechao; Mai, John D; Lee, Gwo-Bin; Li, Wen J

    2014-04-01

    The culturing of cancer cells on micropatterned substrates can provide insight into the factors of the extracellular environment that enable the control of cell growth. We report here a novel non-UV-based technique to quickly micropattern a poly-(ethylene) glycol diacrylate (PEGDA)-based hydrogel on top of modified glass substrates, which were then used to control the growth patterns of breast cancer cells. Previously, the fabrication of micropatterned substrates required relatively complicated steps, which made it impractical for researchers to rapidly and systematically investigate the effects of different cell growth patterns. The technique presented herein operates on the principle of optically-induced electrokinetics (OEKs) and uses computer-generated projection light patterns to dynamically pattern the hydrogel on a hydrogenated amorphous silicon (a-Si:H) thin-film, atop an indium tin oxide (ITO) glass substrate. This technique allows us to pattern lines, circles, pentagons, and more complex shapes in the hydrogel with line widths below 3 μm and thicknesses of up to 6 μm within 8 s by simply controlling the projected illumination pattern and applying an appropriate AC voltage between the two ITO glass substrates. After separating the glass substrates to expose the patterned hydrogel, we experimentally demonstrate that MCF-7 breast cancer cells will adhere to the bare a-Si:H surface, but not to the hydrogel patterned in various geometric shapes and sizes. Theoretical analysis and finite-element model simulations reveal that the dominant OEK forces in our technique are the dielectrophoresis (DEP) force and the electro-osmosis force, which enhance the photo-initiated cross-linking reaction in the hydrogel. Our preliminary cultures of breast cancer cells demonstrate that this reported technique could be applied to effectively confine the growth of cancer cells on a-Si:H surfaces and affect individual cell geometry during their growth. PMID:24531214

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. Seed storage conditions change the germination pattern of clonal growth plants in Mediterranean salt marshes.

    PubMed

    Espinar, José L; García, Luis V; Clemente, Luis

    2005-07-01

    The effect of salinity level and extended exposure to different salinity and flooding conditions on germination patterns of three salt-marsh 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. PMID:21646131

  16. 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

  17. 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. PMID:23894321

  18. The histological growth pattern of colorectal cancer liver metastases has prognostic value.

    PubMed

    Van den Eynden, Gert G; Bird, Nigel C; Majeed, Ali W; Van Laere, Steven; Dirix, Luc Y; Vermeulen, Peter B

    2012-08-01

    Little is known about the biological characteristics that determine the prognosis of colorectal cancer (CRC) liver metastases. In previous work we reported three different histological patterns of the tumour-liver interface of CRC liver metastases, termed the pushing, replacement and desmoplastic growth pattern (GP). The purpose of this study was to confirm differences in angiogenic and hypoxic properties of CRC liver metastases with different GPs in a large data set and to study the value of the GP as a prognostic factor. In 205 patients undergoing a resection of CRC liver metastases, the GP of the metastasis was determined using haematoxylin-eosin and Gordon Sweet's silver staining. The tumour cell proliferation fraction (TCP%), endothelial cell proliferation fraction (ECP%) and carbonic anhydrase 9 (CA9) expression were determined using immunohistochemistry. Standard clinicopathological data and overall survival were recorded. 27.8, 15.6, 34.6 and 17.6 % of liver metastases had a replacement, pushing, desmoplastic and mixed GP, respectively. Analyses of TCP%, ECP% and CA9 expression demonstrated that CRC liver metastases with a replacement GP are non-angiogenic, while the ones with a pushing GP are the most angiogenic with angiogenesis being, at least partially, hypoxia-driven. GP (pushing or not) was the only independent predictor of survival at 2 years. CRC liver metastases grow according to different GP patterns with different angiogenic properties. At 2 years of follow-up a GP with a pushing component was an independent predictor of poor survival, suggesting that the pushing GP is characterized by a more aggressive tumour biology. Further elucidation of the mechanisms and biological pathways involved in and responsible for the differences in GP between CRC liver metastases in different patients might lead to therapeutic agents and strategies taking advantage of this 2 year 'window of opportunity'.

  19. [Growth patterns of juvenile nasopharyngeal fibromas. A histological analysis on the basis of 40 cases].

    PubMed

    Stiller, D; Küttner, K

    1988-01-01

    Juvenile nasopharyngeal angiofibroma is a unique process characterized by an exclusive localization in the nasopharynx of young male patients, and a typical histological pattern composed of angiomatous and fibrous structures. Forty tumors of patients 7 to 25 years of age were investigated. The tumors showed a characteristic zonal organization. Apart from the superficial epithelium the lesions can be subdivided into a subepithelial myxoid-fibrous zone followed by a proliferative capillary fibroblastic cambium layer. In the latter, either the capillary component or the fibroblasts can prevail. The main part is composed of sinus-like vascular channels and a fibrous component. The gaping vascular channels differing in caliber are lined by a single layer of epithelium and surrounded by single or mostly an incomplete rim of smooth muscle cells. Elastic fibres are always lacking. The fibrous component exhibits a changing cellularity and fibre content. Myxoid foci can be encountered, often associated with a pleomorphic cell pattern. Generally, however, fibre structures and foci or large areas of hyalinization predominant in direction to the central parts. In older lesions the fibrous tissue is prevailing. The capillary fibroblastic cambium zone disappears and areas of hyalinization are enlarged. In five cases relapses showing the same structural features were observed. Juvenile nasopharyngeal angiofibromas are discussed as a specific but non-autonomous proliferating growth process which is characterized by 1. specific age and sex incidence, probably in relation to hormones, 2. typical histological pattern and cytological criteria, including local infiltration of the surrounding musculature and bones, 3. origin in the same region corresponding to the membrana buccopharyngea and constant blood supply by the arteria maxillaris interna, or its end artery, the arteria sphenopalatina. According to the corpus cavernosum-like structures, comparable to erectile tissue, the

  20. Correlations between proton-efflux patterns and growth patterns during geotropism and phototropism in maize and sunflower.

    PubMed

    Mulkey, T J; Kuzmanoff, K M; Evans, M L

    1981-07-01

    By placing seedlings of sunflower (Helianthus annuus L.) or maize (Zea mays L.) on agar plates containing a pH indicator dye it is possible to observe surface pH patterns along the growing seedling by observing color changes of the indicator dye. Using this method we find that in geotropically stimulated sunflower hypocotyls or maize coleoptiles there is enhanced proton efflux on the lower surface of the organ prior to the initiation of curvature. As curvature develops the pattern of differential acid efflux becomes more intense. A similar phenomenon is observed when these organs are exposed to unilateral illumination, i.e. enhanced acid efflux occurs on the dark side of the organ prior to the initiation of phototropic curvature and the pattern of differential acid efflux intensifies as phototropic curvature develops. These observations indicate that differential acid efflux occurs in response to tropistic stimuli and that the acid efflux pattern may mediate the development of tropistic curvatures.

  1. [Effects of different irrigation patterns on the growth of maize root hair].

    PubMed

    Hu, Tian-Tian; Kang, Shao-Zhong; Yuan, Li-Na; Li, Zhi-Jun; Zhang, Fu-Cang

    2008-06-01

    With split-root pot experiment and using optical and electrical microscopes, the growth of root hair of maize under different irrigation patterns, i. e. , irrigated on both halves of the pot (conventional irrigation, CI), on one half only (fixed partial root zone irrigation, FPRI), and on both halves alternatively (alternate partial root zone irrigation, APRI), was observed. The observation after 40 days of treatment showed that in non-irrigated root zone of FPRI, the length proportion of root covered by vestigial root hairs was 20.96%, being higher than that in other zones. In addition to some bletting spots, the root system in irrigated zone of FPRI turned yellow, root-branching deteriorated to some extent, and the root hair density on the section with thick root hairs was lower than that in non-irrigated zone. However, both the length proportion of root covered by vestigial root hairs (15.72%) and the deterioration of root hair were lower than those in non-irrigated zone. As for CI, the root appearance and root hair growth were similar to those of the FPRI irrigated zone. As for the early and late irrigated root zones of APRI, the root hair density on the section with thick root hairs was high. The length proportion of root covered by vestigial root hairs was 9.77% and 10.38% for these two root zones, respectively, being lower than that in any root zones of FPRI and CI. It was suggested that alternative partial root zone irrigation was more beneficial to the growth of root hair than fixed partial root zone irrigation and conventional irrigation.

  2. 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

  3. Beyond PubMed: Searching the “Grey Literature” for Clinical Trial Results

    PubMed Central

    2014-01-01

    Clinical trial results have been traditionally communicated through the publication of scholarly reports and reviews in biomedical journals. However, this dissemination of information can be delayed or incomplete, making it difficult to appraise new treatments, or in the case of missing data, evaluate older interventions. Going beyond the routine search of PubMed, it is possible to discover additional information in the “grey literature.” Examples of the grey literature include clinical trial registries, patent databases, company and industrywide repositories, regulatory agency digital archives, abstracts of paper and poster presentations on meeting/congress websites, industry investor reports and press releases, and institutional and personal websites. PMID:25337445

  4. Beyond PubMed: Searching the "Grey Literature" for Clinical Trial Results.

    PubMed

    Citrome, Leslie

    2014-07-01

    Clinical trial results have been traditionally communicated through the publication of scholarly reports and reviews in biomedical journals. However, this dissemination of information can be delayed or incomplete, making it difficult to appraise new treatments, or in the case of missing data, evaluate older interventions. Going beyond the routine search of PubMed, it is possible to discover additional information in the "grey literature." Examples of the grey literature include clinical trial registries, patent databases, company and industrywide repositories, regulatory agency digital archives, abstracts of paper and poster presentations on meeting/congress websites, industry investor reports and press releases, and institutional and personal websites.

  5. [Google and PubMed for physicians: how to find information without getting lost].

    PubMed

    Muñoz Núñez, C F; Sendra Portero, F

    2013-06-01

    Searching on Internet looking for clinically relevant medical information, used as a clinical decision aid tool, for self-learning or for research, is currently a common practice in Radiology. This task has been strengthened by the technological environment where radiologists work with direct access to information sources from the Workstation. The aim of this paper is to review the basic features of information searching tools in order to understand their functions and to optimize medical information searching on Internet. Google, Google Scholar and PubMed are reviewed as models for that purpose.

  6. 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

  7. Weakly faceted cellular patterns versus growth-induced plastic deformation in thin-sample directional solidification of monoclinic biphenyl.

    PubMed

    Börzsönyi, Tamás; Akamatsu, Silvère; Faivre, Gabriel

    2009-11-01

    We present an experimental study of thin-sample directional solidification (T-DS) in impure biphenyl. The platelike growth shape of the monoclinic biphenyl crystals includes two low-mobility (001) facets and four high-mobility {110} facets. Upon T-DS, biphenyl plates oriented with (001) facets parallel to the sample plane can exhibit either a strong growth-induced plastic deformation (GID), or deformation-free weakly faceted (WF) growth patterns. We determine the respective conditions of appearance of these phenomena. GID is shown to be a long-range thermal-stress effect, which disappears when the growth front has a cellular structure. An early triggering of the cellular instability allowed us to avoid GID and study the dynamics of WF patterns as a function of the orientation of the crystal.

  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. Optimized search strategy for detecting scientifically strong studies on treatment through PubMed.

    PubMed

    Corrao, Salvatore; Colomba, Daniela; Argano, Christiano; Calvo, Luigi; Scaglione, Rosario; Licata, Giuseppe

    2012-06-01

    Our study was designed to optimize the search strategies based on the work of Haynes et al. for detecting randomized controlled trials (RCTs) through PubMed. In particular, we aimed to improve precision for broad and narrow searches on interventional studies. We used in addition to the string suggested by the Hedge Team the following: {NOT ((animals [mh] NOT humans [mh]) OR (review [pt] OR meta-analysis [pt]))} and tested its effectiveness. The search was carried out on a year's worth of articles from the PubMed database. We analyzed 35,590 bibliographic citations about four relevant major topics in internal medicine (hypertension, diabetes, heart failure, and hepatitis). Precision, percentage gain between the Hedge Team search strategies and the new one were computed and reported in the text. Moreover, a pooled analysis was carried out in terms of absolute precision difference. We observed better precision for both broad and narrow searches. However, effective gain resulted only for broad searches. In this case, bibliographic citation recall effectively reduced (-24 to -35 % retrieved citation with a gain of 32-54 %) without loss of information. The search strategy improved broad searches regarding each of the four considered topics. We think this new search strategy, based on a previous work of the Hedge team, could be a step forward and can save some time by researchers. PMID:22426813

  10. Improving efficacy of PubMed Clinical Queries for retrieving scientifically strong studies on treatment.

    PubMed

    Corrao, Salvatore; Colomba, Daniela; Arnone, Sabrina; Argano, Christiano; Di Chiara, Tiziana; Scaglione, Rosario; Licata, Giuseppe

    2006-01-01

    The authors evaluated the retrieval power of PubMed "Clinical Queries," narrow search string, about therapy in comparison with a modified search string to avoid possible retrieval bias. PubMed search strategy was compared to a slightly modified string that included the Britannic English term "randomised." The authors tested the two strings joined onto each of four terms concerning topics of broad interest: hypertension, hepatitis, diabetes, and heart failure. In particular, precision was computed for not-indexed citations. The added word "randomised" improved total citation retrieval in any case. Total retrieval gain for not-indexed citations ranged from 11.1% to 21.4%. A significant number of Randomized Controlled Trial(s) (RCT)s (9.1-18.2%) was retrieved for each of the selected topics. They were often recently published RCTs. The authors think that correction of the Clinical Queries filter (when they focus on therapy and use narrow searches) is necessary to avoid biased search results with loss of relevant and up-to-date scientifically sound information. PMID:16799123

  11. 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

  12. 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.

  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. 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. PMID:26925324

  15. 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.

  16. 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

  17. 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

  18. Age, growth, and recruitment patterns of juvenile ladyfish (Elops sp) from the east coast of Florida (USA).

    PubMed

    Levesque, Juan C

    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

  19. 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.

  20. Application of patterned growth of aligned zinc oxide nanoarrays by mirocontact printing in quantum dots-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Deng, Jianping; Wang, Minqiang; Yang, Zhi; Liu, Jing; Sun, Zhongwang; Song, Xiaohui

    2015-04-01

    This paper describes a simple method for patterned growth of ZnO nanoarrays (NAs) that is based on a combination of the microcontact printing process for patterning ZnO seed films and the low-temperature hydrothermal approach for depositing ZnO NAs. The patterned ZnO seed films were achieved via printing patterned TiO2 sol on ZnO seed films. It is found that the pattern quality is mainly affected by the viscosity of TiO2 ink and the pressure including value and direction. To assess the possibility of patterned ZnO NAs applied to devices, the patterned ZnO NAs were used as light scattering layer in CdSe-sensitized solar cells. The diffuse-reflection, absorption and transmission spectra show that the patterned ZnO NAs greatly enhance the light scattering and absorbance in the visible range. The enhancement of cell performance is attributed to the patterned ZnO NAs: 1) multiple-light scattering improves the light absorbance, and 2) NAs with high electron mobility facilitate the electron collection.

  1. The pathology of urinary bladder lesions with an inverted growth pattern.

    PubMed

    Guo, Aitao; Liu, Aijun; Teng, Xiaodong

    2016-02-01

    Inverted lesions in the urinary bladder have been the source of some difficulty in urological pathology. The two common ones are von Brunn's nests and cystitis cystic/cystitis glandularis, which are considered normal variants of urothelium. Apart from them, a number of other rare urothelial lesions with inverted growth pattern occur in the urinary bladder. Some of them are only reactive conditions, just as pseudocarcinomatous hyperplasia. Some are benign tumors, namely inverted papilloma. Whereas others are malignant neoplasms, including inverted papillary urothelial neoplasm of low malignant potential (PUNLMP), non-invasive inverted papillary urothelial carcinoma (low-grade and high-grade), and invasive urothelial carcinoma (inverted, nested and big nested variants). Because of the overlapping morphological features of all the inverted lesions mentioned above, even between high-grade invasive carcinoma and pseudocarcinomatous hyperplasia which are only a kind of reactive conditions, it is very important for the surgical pathologist to recognize and be familiar with these inverted lesions in urinary bladder. In this article, we review these spectrums of inverted lesions of the urinary bladder. Emphasis is placed on histogenesis, morphology, differential diagnosis of these lesions, and the pathologic grading of the non-invasive inverted neoplasms, such as inverted papilloma, inverted PUNLMP, non-invasive inverted papillary urothelial carcinoma with low-grade, and non-invasive inverted papillary urothelial carcinoma with high-grade.

  2. The pathology of urinary bladder lesions with an inverted growth pattern

    PubMed Central

    Liu, Aijun; Teng, Xiaodong

    2016-01-01

    Inverted lesions in the urinary bladder have been the source of some difficulty in urological pathology. The two common ones are von Brunn’s nests and cystitis cystic/cystitis glandularis, which are considered normal variants of urothelium. Apart from them, a number of other rare urothelial lesions with inverted growth pattern occur in the urinary bladder. Some of them are only reactive conditions, just as pseudocarcinomatous hyperplasia. Some are benign tumors, namely inverted papilloma. Whereas others are malignant neoplasms, including inverted papillary urothelial neoplasm of low malignant potential (PUNLMP), non-invasive inverted papillary urothelial carcinoma (low-grade and high-grade), and invasive urothelial carcinoma (inverted, nested and big nested variants). Because of the overlapping morphological features of all the inverted lesions mentioned above, even between high-grade invasive carcinoma and pseudocarcinomatous hyperplasia which are only a kind of reactive conditions, it is very important for the surgical pathologist to recognize and be familiar with these inverted lesions in urinary bladder. In this article, we review these spectrums of inverted lesions of the urinary bladder. Emphasis is placed on histogenesis, morphology, differential diagnosis of these lesions, and the pathologic grading of the non-invasive inverted neoplasms, such as inverted papilloma, inverted PUNLMP, non-invasive inverted papillary urothelial carcinoma with low-grade, and non-invasive inverted papillary urothelial carcinoma with high-grade. PMID:27041933

  3. 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.

  4. 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.

  5. Low-dose total body irradiation versus combination chemotherapy for lymphomas with follicular growth pattern.

    PubMed

    Meerwaldt, J H; Carde, P; Burgers, J M; Monconduit, M; Thomas, J; Somers, R; Sizoo, W; Glabbeke, M V; Duez, N; de Wolf-Peeters, C

    1991-10-01

    The treatment of Non-Hodgkin's lymphomas with follicular growth pattern and advanced stage of disease remains controversial. Treatments varying from no initial treatment up to aggressive combination chemotherapy have been advocated. The EORTC Lymphoma Cooperative Group has performed a randomized prospective trial comparing short duration low dose total body irradiation (TBI) vs combination chemotherapy (CHVmP) + consolidation radiotherapy. Ninety-three patients were entered; of 84 evaluable patients, 44 received TBI and 40 CHVmP. Complete remission (CR) rates were 36%--TBI and 55%--CHVmP, but overall response rates were identical, 76 versus 69%. No significant difference in freedom from progression or survival was observed. No unexpected toxicity was seen. Although numbers are small, we cannot conclude that aggressive combination chemo-radiotherapy resulted in a better survival. Our analysis confirms that there is a constant risk of relapse. Other approaches should be explored if survival benefit is the ultimate goal in treatment of this patient population. PMID:1938514

  6. 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.

  7. 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

  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. Growth patterns of dendrimers and electric potential oscillations during electropolymerization of pyrrole using mono- and mixed surfactants.

    PubMed

    Das, Ishwar; Goel, Neha; Agrawal, Namita R; Gupta, Sanjeev Kumar

    2010-10-14

    Fractal and dendrimer growth patterns of polypyrrole were obtained during electrochemical polymerization of pyrrole in systems (A) pyrrole-sodium dodecyl sulfate (NaDS)-water and (B) pyrrole-NaDS-cetyl trimethyl ammonium bromide (CTAB)-water. Different morphological transitions including compact → flower-like and fractal → dendrimer → fractal were observed depending on experimental conditions. Growth kinetics during electropolymerization of pyrrole was studied. Growth rate was found to be higher in system A than in B. Effect of [NaDS], [pyrrole], and field intensity on morphology and weight of polymer aggregates was also studied in both the systems. Different empirical equations were obeyed under different conditions. Electropolymerized aggregates were characterized by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), electrical conductivity measurement, and reflectance spectroscopy. TEM studies revealed that the particle size decreased to ∼140-200 nm in the presence of CTAB. The decrease in particle size on addition of CTAB was also observed in XRD studies. Reflectance spectra of the polymer aggregates support the large π-conjugation in the dendrimer. During electropolymerization, oscillations in potential were monitored as a function of time. Results indicated that growth pattern and electric potential oscillations were interrelated. In the case of fractal growth, the amplitude of chaotic oscillation was higher than the amplitude of oscillation during the growth of dendrimer. Growth morphologies and electric potential oscillations have been explained on the basis of modified Diaz's mechanism.

  10. 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…

  11. 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

  12. 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.

  13. Mechanical constraints imposed by 3D cellular geometry and arrangement modulate growth patterns in the Arabidopsis embryo.

    PubMed

    Bassel, George W; Stamm, Petra; Mosca, Gabriella; Barbier de Reuille, Pierre; Gibbs, Daniel J; Winter, Robin; Janka, Ales; Holdsworth, Michael J; Smith, Richard S

    2014-06-10

    Morphogenesis occurs in 3D space over time and is guided by coordinated gene expression programs. Here we use postembryonic development in Arabidopsis plants to investigate the genetic control of growth. We demonstrate that gene expression driving the production of the growth-stimulating hormone gibberellic acid and downstream growth factors is first induced within the radicle tip of the embryo. The center of cell expansion is, however, spatially displaced from the center of gene expression. Because the rapidly growing cells have very different geometry from that of those at the tip, we hypothesized that mechanical factors may contribute to this growth displacement. To this end we developed 3D finite-element method models of growing custom-designed digital embryos at cellular resolution. We used this framework to conceptualize how cell size, shape, and topology influence tissue growth and to explore the interplay of geometrical and genetic inputs into growth distribution. Our simulations showed that mechanical constraints are sufficient to explain the disconnect between the experimentally observed spatiotemporal patterns of gene expression and early postembryonic growth. The center of cell expansion is the position where genetic and mechanical facilitators of growth converge. We have thus uncovered a mechanism whereby 3D cellular geometry helps direct where genetically specified growth takes place.

  14. 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.

  15. 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. PMID:24862838

  16. Biomedicine's electronic publishing paradigm shift: copyright policy and PubMed Central.

    PubMed

    Markovitz, B P

    2000-01-01

    Biomedical publishing stands at a crossroads. The traditional print, peer-reviewed, subscription journal has served science well but is now being called into question. Because of spiraling print journal costs and the worldwide acceptance of the Internet as a valid publication medium, there is a compelling opportunity to re-examine our current paradigm and future options. This report illustrates the conflicts and restrictions inherent in the current publishing model and examines how the single act of permitting authors to retain copyright of their scholarly manuscripts may preserve the quality-control function of the current journal system while allowing PubMed Central, the Internet archiving system recently proposed by the director of the National Institutes of Health, to simplify and liberate access to the world's biomedical literature.

  17. Modeling Actions of PubMed Users with N-Gram Language Models*

    PubMed Central

    Lin, Jimmy; Wilbur, W. John

    2008-01-01

    Transaction logs from online search engines are valuable for two reasons: First, they provide insight into human information-seeking behavior. Second, log data can be used to train user models, which can then be applied to improve retrieval systems. This article presents a study of logs from PubMed®, the public gateway to the MEDLINE® database of bibliographic records from the medical and biomedical primary literature. Unlike most previous studies on general Web search, our work examines user activities with a highly-specialized search engine. We encode user actions as string sequences and model these sequences using n-gram language models. The models are evaluated in terms of perplexity and in a sequence prediction task. They help us better understand how PubMed users search for information and provide an enabler for improving users’ search experience. PMID:19684883

  18. 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

  19. Scaling in the growth of geographically subdivided populations: invariant patterns from a continent-wide biological survey.

    PubMed

    Keitt, Timothy H; Amaral, Luis A N; Buldyrev, Sergey V; Stanley, H Eugene

    2002-05-29

    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.

  20. A Bibliometric Analysis of PubMed Literature on Middle East Respiratory Syndrome.

    PubMed

    Wang, Zhengting; Chen, Yongdi; Cai, Gaofeng; Jiang, Zhenggang; Liu, Kui; Chen, Bin; Jiang, Jianmin; Gu, Hua

    2016-01-01

    Middle East Respiratory Syndrome (MERS), a pandemic threat to human beings, has aroused huge concern worldwide, but no bibliometric studies have been conducted on MERS research. The aim of this study was to map research productivity on the disease based on the articles indexed in PubMed. The articles related to MERS dated from 2012 to 2015 were retrieved from PubMed. The articles were classified into three categories according to their focus. Publication outputs were assessed and frequently used terms were mapped using the VOS viewer software. A total of 443 articles were included for analysis. They were published in 162 journals, with Journal of Virology being the most productive (44 articles; 9.9%) and by six types of organizations, with universities being the most productive (276 articles; 62.4%).The largest proportion of the articles focused on basic medical sciences and clinical studies (47.2%) and those on prevention and control ranked third (26.2%), with those on other focuses coming in between (26.6%). The articles on prevention and control had the highest mean rank for impact factor (IF) (226.34), followed by those on basic medical sciences and clinical studies (180.23) and those on other focuses (168.03). The mean rank differences were statistically significant (p = 0.000). Besides, "conronavirus", "case", "transmission" and "detection" were found to be the most frequently used terms. The findings of this first bibliometric study on MERS suggest that the prevention and control of the disease has become a big concern and related research should be strengthened. PMID:27304963

  1. A Bibliometric Analysis of PubMed Literature on Middle East Respiratory Syndrome

    PubMed Central

    Wang, Zhengting; Chen, Yongdi; Cai, Gaofeng; Jiang, Zhenggang; Liu, Kui; Chen, Bin; Jiang, Jianmin; Gu, Hua

    2016-01-01

    Middle East Respiratory Syndrome (MERS), a pandemic threat to human beings, has aroused huge concern worldwide, but no bibliometric studies have been conducted on MERS research. The aim of this study was to map research productivity on the disease based on the articles indexed in PubMed. The articles related to MERS dated from 2012 to 2015 were retrieved from PubMed. The articles were classified into three categories according to their focus. Publication outputs were assessed and frequently used terms were mapped using the VOS viewer software. A total of 443 articles were included for analysis. They were published in 162 journals, with Journal of Virology being the most productive (44 articles; 9.9%) and by six types of organizations, with universities being the most productive (276 articles; 62.4%).The largest proportion of the articles focused on basic medical sciences and clinical studies (47.2%) and those on prevention and control ranked third (26.2%), with those on other focuses coming in between (26.6%). The articles on prevention and control had the highest mean rank for impact factor (IF) (226.34), followed by those on basic medical sciences and clinical studies (180.23) and those on other focuses (168.03). The mean rank differences were statistically significant (p = 0.000). Besides, “conronavirus”, “case”, “transmission” and “detection” were found to be the most frequently used terms. The findings of this first bibliometric study on MERS suggest that the prevention and control of the disease has become a big concern and related research should be strengthened. PMID:27304963

  2. 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.

  3. PubMed vs. HighWire Press: a head-to-head comparison of two medical literature search engines.

    PubMed

    Vanhecke, Thomas E; Barnes, Michael A; Zimmerman, Janet; Shoichet, Sandor

    2007-09-01

    PubMed and HighWire Press are both useful medical literature search engines available for free to anyone on the internet. We measured retrieval accuracy, number of results generated, retrieval speed, features and search tools on HighWire Press and PubMed using the quick search features of each. We found that using HighWire Press resulted in a higher likelihood of retrieving the desired article and higher number of search results than the same search on PubMed. PubMed was faster than HighWire Press in delivering search results regardless of search settings. There are considerable differences in search features between these two search engines.

  4. 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.

  5. 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.

  6. Hybridization between Yellowstone Cutthroat Trout and Rainbow Trout Alters the Expression of Muscle Growth-Related Genes and Their Relationships with Growth Patterns

    PubMed Central

    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. PMID:26485525

  7. Population Growth in the 1990s: Patterns within the United States.

    ERIC Educational Resources Information Center

    Perry, Marc

    2002-01-01

    Examines population growth during the 1990s for a variety of geographic levels including regions, divisions, states, metropolitan areas, counties, and large cities. Compares growth rates for the 1990s with earlier decades to provide an historical context for present-day trends in population growth and decline. Discusses how differential population…

  8. Lithography-free plasma-induced patterned growth of MoS2 and its heterojunction with graphene.

    PubMed

    Chen, Xiang; Park, Yong Ju; Das, Tanmoy; Jang, Houk; Lee, Jae-Bok; Ahn, Jong-Hyun

    2016-08-18

    Application-oriented patterned growth of transition metal dichalcogenides (TMDCs) and their heterojunctions is of critical importance for sophisticated, customized two-dimensional (2D) electronic and optoelectronic devices; however, it is still difficult to fabricate these patterns in a simple, clean, and high controllability manner without using optical lithography. Here, we report the direct synthesis of patterned MoS2 and graphene-MoS2 heterojunctions via selective plasma treatment of a SiO2/Si substrate and chemical vapor deposition of MoS2. This method has multiple merits, such as simple steps, a short operating time, easily isolated MoS2 layers with clean surfaces and controllable locations, shapes, sizes and thicknesses, which enable their integration into the device structure without using a photoresist. In addition, we demonstrate the direct growth of patterned graphene-MoS2 heterojunctions for the fabrication of transistor. This study reveals a novel method to fabricate and use patterned MoS2 and graphene-MoS2 heterojunctions, which could be generalized to the rational design of other 2D materials, heterojunctions and devices in the future. PMID:27432242

  9. Lithography-free plasma-induced patterned growth of MoS2 and its heterojunction with graphene.

    PubMed

    Chen, Xiang; Park, Yong Ju; Das, Tanmoy; Jang, Houk; Lee, Jae-Bok; Ahn, Jong-Hyun

    2016-08-18

    Application-oriented patterned growth of transition metal dichalcogenides (TMDCs) and their heterojunctions is of critical importance for sophisticated, customized two-dimensional (2D) electronic and optoelectronic devices; however, it is still difficult to fabricate these patterns in a simple, clean, and high controllability manner without using optical lithography. Here, we report the direct synthesis of patterned MoS2 and graphene-MoS2 heterojunctions via selective plasma treatment of a SiO2/Si substrate and chemical vapor deposition of MoS2. This method has multiple merits, such as simple steps, a short operating time, easily isolated MoS2 layers with clean surfaces and controllable locations, shapes, sizes and thicknesses, which enable their integration into the device structure without using a photoresist. In addition, we demonstrate the direct growth of patterned graphene-MoS2 heterojunctions for the fabrication of transistor. This study reveals a novel method to fabricate and use patterned MoS2 and graphene-MoS2 heterojunctions, which could be generalized to the rational design of other 2D materials, heterojunctions and devices in the future.

  10. Microbial Patterns Signaling via Toll-Like Receptors 2 and 5 Contribute to Epithelial Repair, Growth and Survival

    PubMed Central

    Shaykhiev, Renat; Behr, Jürgen; Bals, Robert

    2008-01-01

    Epithelial cells (ECs) continuously interact with microorganisms and detect their presence via different pattern-recognition receptors (PRRs) including Toll-like receptors (TLRs). Ligation of epithelial TLRs by pathogens is usually associated with the induction of pro-inflammatory mediators and antimicrobial factors. In this study, using human airway ECs as a model, we found that detection of microbial patterns via epithelial TLRs directly regulates tissue homeostasis. Staphylococcus aureus (S. aureus) and microbial patterns signaling via TLR2 and TLR5 induce a set of non-immune epithelial responses including cell migration, wound repair, proliferation, and survival of primary and cancerous ECs. Using small interfering RNA (siRNA) gene targeting, receptor-tyrosine kinase microarray and inhibition studies, we determined that TLR and the epidermal growth factor receptor (EGFR) mediate the stimulating effect of microbial patterns on epithelial repair. Microbial patterns signaling via Toll-like receptors 2 and 5 contribute to epithelial repair, growth and survival. This effect is independent of hematopoietic and other cells as well as inflammatory cytokines suggesting that epithelia are able to regulate their integrity in an autonomous non-inflammatory manner by sensing microbes directly via TLRs. PMID:18167552

  11. Net Improvement of Correct Answers to Therapy Questions After PubMed Searches: Pre/Post Comparison

    PubMed Central

    Keepanasseril, Arun

    2013-01-01

    Background Clinicians search PubMed for answers to clinical questions although it is time consuming and not always successful. Objective 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). Methods 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. Results 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. Conclusions 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

  12. Arabidopsis JAGGED links floral organ patterning to tissue growth by repressing Kip-related cell cycle inhibitors

    PubMed Central

    Schiessl, Katharina; Muiño, Jose M.; Sablowski, Robert

    2014-01-01

    Plant morphogenesis requires coordinated cytoplasmic growth, oriented cell wall extension, and cell cycle progression, but it is debated which of these processes are primary drivers for tissue growth and directly targeted by developmental genes. Here, we used ChIP high-throughput sequencing combined with transcriptome analysis to identify global target genes of the Arabidopsis transcription factor JAGGED (JAG), which promotes growth of the distal region of floral organs. Consistent with the roles of JAG during organ initiation and subsequent distal organ growth, we found that JAG directly repressed genes involved in meristem development, such as CLAVATA1 and HANABA TARANU, and genes involved in the development of the basal region of shoot organs, such as BLADE ON PETIOLE 2 and the GROWTH REGULATORY FACTOR pathway. At the same time, JAG regulated genes involved in tissue polarity, cell wall modification, and cell cycle progression. In particular, JAG directly repressed KIP RELATED PROTEIN 4 (KRP4) and KRP2, which control the transition to the DNA synthesis phase (S-phase) of the cell cycle. The krp2 and krp4 mutations suppressed jag defects in organ growth and in the morphology of petal epidermal cells, showing that the interaction between JAG and KRP genes is functionally relevant. Our work reveals that JAG is a direct mediator between genetic pathways involved in organ patterning and cellular functions required for tissue growth, and it shows that a regulatory gene shapes plant organs by releasing a constraint on S-phase entry. PMID:24497510

  13. The influence of growth patterns on sexual size monomorphism in lemurs.

    PubMed

    Tennenhouse, E M

    2015-09-01

    The lack of sexual size dimorphism among lemurs is puzzling given the high degree of polygyny in this clade. It has been proposed that the unique ecological conditions of Madagascar favour rapid completion of growth, limiting the opportunities for bimaturism and sexual size dimorphism in lemurs. Using recently compiled large data sets on many species across the lemur clade, I examined the prevalence of sexual size monomorphism of body mass among lemurs and tested the hypothesis that limited growth durations constrain sexual size dimorphism. I used segmented regression analyses to accurately model growth in each species. The majority of species analysed exhibited a period of rapid growth followed by a distinct period of slow growth prior to attainment of adult body mass. Whereas the first period of growth was constrained by the need to attain the majority of adult body mass prior to the onset of the infant's first dry season, the subsequent period of slow growth was unconstrained and sufficiently long to promote sexual bimaturism. Sex differences in the duration and rate of growth during this second growth phase appeared to account for the sexual size dimorphism exhibited by three lemur species. Therefore, constraints on growth processes do not limit sexual size dimorphism in lemurs, and other explanations for the prevalence of sexual size monomorphism in this clade should be examined. The importance of considering ontogeny in future investigations of sexual size monomorphism in lemurs is highlighted. PMID:26134876

  14. A Search Engine to Access PubMed Monolingual Subsets: Proof of Concept and Evaluation in French

    PubMed Central

    Schuers, Matthieu; Soualmia, Lina Fatima; Grosjean, Julien; Kerdelhué, Gaétan; Kergourlay, Ivan; Dahamna, Badisse; Darmoni, Stéfan Jacques

    2014-01-01

    Background PubMed contains numerous articles in languages other than English. However, existing solutions to access these articles in the language in which they were written remain unconvincing. Objective The aim of this study was to propose a practical search engine, called Multilingual PubMed, which will permit access to a PubMed subset in 1 language and to evaluate the precision and coverage for the French version (Multilingual PubMed-French). Methods To create this tool, translations of MeSH were enriched (eg, adding synonyms and translations in French) and integrated into a terminology portal. PubMed subsets in several European languages were also added to our database using a dedicated parser. The response time for the generic semantic search engine was evaluated for simple queries. BabelMeSH, Multilingual PubMed-French, and 3 different PubMed strategies were compared by searching for literature in French. Precision and coverage were measured for 20 randomly selected queries. The results were evaluated as relevant to title and abstract, the evaluator being blind to search strategy. Results More than 650,000 PubMed citations in French were integrated into the Multilingual PubMed-French information system. The response times were all below the threshold defined for usability (2 seconds). Two search strategies (Multilingual PubMed-French and 1 PubMed strategy) showed high precision (0.93 and 0.97, respectively), but coverage was 4 times higher for Multilingual PubMed-French. Conclusions It is now possible to freely access biomedical literature using a practical search tool in French. This tool will be of particular interest for health professionals and other end users who do not read or query sufficiently in English. The information system is theoretically well suited to expand the approach to other European languages, such as German, Spanish, Norwegian, and Portuguese. PMID:25448528

  15. Sex Disparity in Food Allergy: Evidence from the PubMed Database.

    PubMed

    Kelly, Caleb; Gangur, Venu

    2009-01-01

    Food allergies are potentially fatal immune-mediated disorders that are growing globally. The relationship between sex and food allergy remains incompletely understood. Here we tested the hypothesis that, should sex influence the clinical response to food allergens, this would be reflected by a sex disparity in published studies of food allergy. We performed a systematic search of the PubMed literature for IgE-mediated allergy to 11 allergenic foods of international regulatory importance. No date restriction was used and only articles in English were considered. Of the 4744 articles retrieved, 591 met the inclusion criteria representing 17528 subjects with food allergies. Whereas among children with food allergies, 64.35% were males and 35.65% were females (male/female ratio, 1.80), among adults 34.82% were males and 65.18% were females (male/female ratio, 0.53). Consequently, these data argue that there is need for further investigation to define the role of sex in the pathogenesis of food allergy.

  16. Homo and heteroepitaxial growth and study of orientation-patterned GaP for nonlinear frequency conversion devices

    NASA Astrophysics Data System (ADS)

    Tassev, V. L.; Vangala, S.; Peterson, R.; Kimani, M.; Snure, M.; Markov, I.

    2016-03-01

    Frequency conversion in orientation-patterned quasi-phase matched materials is a leading approach for generating tunable mid- and long-wave coherent IR radiation for a wide variety of applications. A number of nonlinear optical materials are currently under intensive investigation. Due to their unique properties, chiefly wide IR transparency and high nonlinear susceptibility, GaAs and GaP are among the most promising. Compared to GaAs, GaP has the advantage of having higher thermal conductivity and significantly lower 2PA in the convenient pumping range of 1- 1.7 μm. HVPE growth of OPGaP, however, has encountered certain challenges: low quality and high price of commercially available GaP wafers; and strong parasitic nucleation during HVPE growth that reduces growth rate and aggravates layer quality, often leading to pattern overgrowth. Lessons learned from growing OPGaAs were not entirely helpful, leaving us to alternative solutions for both homoepitaxial growth and template preparation. We report repeatable one-step HVPE growth of up to 400 μm thick OPGaP with excellent domain fidelity deposited for first time on OPGaAs templates. The templates were prepared by wafer fusion bonding or MBE assisted polarity inversion technique. A close to equilibrium growth at such a large lattice mismatch (-3.6%) is itself noteworthy, especially when previously reported attempts (growth of OPZnSe on OPGaAs templates) at much smaller mismatch (+0.3%) have produced limited results. Combining the advantages of the two most promising materials, GaAs and GaP, is a solution that will accelerate the development of high power, tunable laser sources for the mid- and long-wave IR, and THz region.

  17. Bone microstructure and the evolution of growth patterns in Permo-Triassic therocephalians (Amniota, Therapsida) of South Africa

    PubMed Central

    Botha-Brink, Jennifer

    2014-01-01

    Therocephalians were a speciose clade of nonmammalian therapsids whose ecological diversity and survivorship of the end-Permian mass extinction offer the potential to investigate the evolution of growth patterns across the clade and their underlying influences on post-extinction body size reductions, or ‘Lilliput effects’. We present a phylogenetic survey of limb bone histology and growth patterns in therocephalians from the Middle Permian through Middle Triassic of the Karoo Basin, South Africa. Histologic sections were prepared from 80 limb bones representing 11 genera of therocephalians. Histologic indicators of skeletal growth, including cortical vascularity (%CV) and mean primary osteon diameters (POD), were evaluated in a phylogenetic framework and assessed for correlations with other biologically significant variables (e.g., size and robusticity). Changes in %CV and POD correlated strongly with evolutionary changes in body size (i.e., smaller-bodied descendants tended to have lower %CV than their larger-bodied ancestors across the tree). Bone wall thickness tended to be high in early therocephalians and lower in the gracile-limbed baurioids, but showed no general correlation with cross-sectional area or degree of vascularity (and, thus, growth). Clade-level patterns, however, deviated from previously studied within-lineage patterns. For example, Moschorhinus, one of few therapsid genera to have survived the extinction boundary, demonstrated higher %CV in the Triassic than in the Permian despite its smaller size in the extinction aftermath. Results support a synergistic model of size reductions for Triassic therocephalians, influenced both by within-lineage heterochronic shifts in survivor taxa (as reported in Moschorhinus and the dicynodont Lystrosaurus) and phylogenetically inferred survival of small-bodied taxa that had evolved short growth durations (e.g., baurioids). These findings mirror the multi-causal Lilliput patterns described in marine faunas

  18. Bone microstructure and the evolution of growth patterns in Permo-Triassic therocephalians (Amniota, Therapsida) of South Africa.

    PubMed

    Huttenlocker, Adam K; Botha-Brink, Jennifer

    2014-01-01

    Therocephalians were a speciose clade of nonmammalian therapsids whose ecological diversity and survivorship of the end-Permian mass extinction offer the potential to investigate the evolution of growth patterns across the clade and their underlying influences on post-extinction body size reductions, or 'Lilliput effects'. We present a phylogenetic survey of limb bone histology and growth patterns in therocephalians from the Middle Permian through Middle Triassic of the Karoo Basin, South Africa. Histologic sections were prepared from 80 limb bones representing 11 genera of therocephalians. Histologic indicators of skeletal growth, including cortical vascularity (%CV) and mean primary osteon diameters (POD), were evaluated in a phylogenetic framework and assessed for correlations with other biologically significant variables (e.g., size and robusticity). Changes in %CV and POD correlated strongly with evolutionary changes in body size (i.e., smaller-bodied descendants tended to have lower %CV than their larger-bodied ancestors across the tree). Bone wall thickness tended to be high in early therocephalians and lower in the gracile-limbed baurioids, but showed no general correlation with cross-sectional area or degree of vascularity (and, thus, growth). Clade-level patterns, however, deviated from previously studied within-lineage patterns. For example, Moschorhinus, one of few therapsid genera to have survived the extinction boundary, demonstrated higher %CV in the Triassic than in the Permian despite its smaller size in the extinction aftermath. Results support a synergistic model of size reductions for Triassic therocephalians, influenced both by within-lineage heterochronic shifts in survivor taxa (as reported in Moschorhinus and the dicynodont Lystrosaurus) and phylogenetically inferred survival of small-bodied taxa that had evolved short growth durations (e.g., baurioids). These findings mirror the multi-causal Lilliput patterns described in marine faunas, but

  19. Growth and reproductive patterns of Undaria pinnatifida sporophytes in a cultivation farm in Busan, Korea

    PubMed Central

    Kim, Young Sik; Lee, Soon Jeong

    2006-01-01

    Monthly growth and reproduction of Undaria pinnatifida sporophytes were examined over a period of 5 months in a cultivation farm in Korea. A total of 11 characters of Undaria were measured to determine a reliable morphological character representing its growth and reproduction. Plant weight of Undaria sporophytes increased steadily over the experimental period, but it increased in four different ways. Undaria pinnatifida increased body weight by growth in length and width (October–early December), and by growth in width with the thickening of blade and stipe when sporophytes began to be fertile (December–January). In the middle of January, growth in length and width had almost stopped with the maturation of Undaria sporophytes. Finally, the weight of Undaria increased again by growth in width at the end of February. Present results indicate that Undaria sporophytes increase body weight by growth in length and width at different times, and the relationship between reproduction and vegetative growth is exclusive. Plant weight was positively correlated and fitted well with stipe width and blade width. The blade of Undaria was very thin (ca. 254 μm) and breakable by wave action, but its stipe was strong and relatively thick (ca. 8.7 mm). Furthermore, the fertility of U. pinnatifida was fitted better with stipe width than blade width. Thus, we suggest that the stipe width is the most feasible character with which to estimate the growth and reproduction of U. pinnatifida sporophytes in the cultivation farm. PMID:19396348

  20. Mistletoe effects on Scots pine decline following drought events: insights from within-tree spatial patterns, growth and carbohydrates.

    PubMed

    Sangüesa-Barreda, Gabriel; Linares, Juan Carlos; Camarero, J Julio

    2012-05-01

    Forest decline has been attributed to the interaction of several stressors including biotic factors such as mistletoes and climate-induced drought stress. However, few data exist on how mistletoes are spatially arranged within trees and how this spatial pattern is related to changes in radial growth, responses to drought stress and carbon use. We used dendrochronology to quantify how mistletoe (Viscum album L.) infestation and drought stress affected long-term growth patterns in Pinus sylvestris L. at different heights. Basal area increment (BAI) trends and comparisons between trees of three different infestation degrees (without mistletoe, ID1; moderately infested trees, ID2; and severely infested trees, ID3) were performed using linear mixed-effects models. To identify the main climatic drivers of tree growth tree-ring widths were converted into indexed chronologies and related to climate data using correlation functions. We performed spatial analyses of the 3D distribution of mistletoe individuals and their ages within the crowns of three severely infested pines to describe their patterns. Lastly, we quantified carbohydrate and nitrogen concentrations in needles and sapwood of branches from severely infested trees and from trees without mistletoe. Mistletoe individuals formed strongly clustered groups of similar age within tree crowns and their age increased towards the crown apex. Mistletoe infestation negatively impacted growth but this effect was stronger near the tree apex than in the rest of sampled heights, causing an average loss of 64% in BAI (loss of BAI was ∼51% at 1.3 m or near the tree base). We found that BAI of severely infested trees and moderately or non-infested trees diverged since 2001 and such divergence was magnified by drought. Infested trees had lower concentrations of soluble sugars in their needles than non-infested ones. We conclude that mistletoe infestation causes growth decline and increases the sensitivity of trees to drought

  1. Mistletoe effects on Scots pine decline following drought events: insights from within-tree spatial patterns, growth and carbohydrates.

    PubMed

    Sangüesa-Barreda, Gabriel; Linares, Juan Carlos; Camarero, J Julio

    2012-05-01

    Forest decline has been attributed to the interaction of several stressors including biotic factors such as mistletoes and climate-induced drought stress. However, few data exist on how mistletoes are spatially arranged within trees and how this spatial pattern is related to changes in radial growth, responses to drought stress and carbon use. We used dendrochronology to quantify how mistletoe (Viscum album L.) infestation and drought stress affected long-term growth patterns in Pinus sylvestris L. at different heights. Basal area increment (BAI) trends and comparisons between trees of three different infestation degrees (without mistletoe, ID1; moderately infested trees, ID2; and severely infested trees, ID3) were performed using linear mixed-effects models. To identify the main climatic drivers of tree growth tree-ring widths were converted into indexed chronologies and related to climate data using correlation functions. We performed spatial analyses of the 3D distribution of mistletoe individuals and their ages within the crowns of three severely infested pines to describe their patterns. Lastly, we quantified carbohydrate and nitrogen concentrations in needles and sapwood of branches from severely infested trees and from trees without mistletoe. Mistletoe individuals formed strongly clustered groups of similar age within tree crowns and their age increased towards the crown apex. Mistletoe infestation negatively impacted growth but this effect was stronger near the tree apex than in the rest of sampled heights, causing an average loss of 64% in BAI (loss of BAI was ∼51% at 1.3 m or near the tree base). We found that BAI of severely infested trees and moderately or non-infested trees diverged since 2001 and such divergence was magnified by drought. Infested trees had lower concentrations of soluble sugars in their needles than non-infested ones. We conclude that mistletoe infestation causes growth decline and increases the sensitivity of trees to drought

  2. Increased water use efficiency but contrasting tree growth patterns in Fitzroya cupressoides forests of southern Chile during recent decades

    NASA Astrophysics Data System (ADS)

    Urrutia-Jalabert, Rocío.; Malhi, Yadvinder; Barichivich, Jonathan; Lara, Antonio; Delgado-Huertas, Antonio; Rodríguez, Carmen Gloria; Cuq, Emilio

    2015-12-01

    Little is known about how old-growth and massive forests are responding to environmental change. We investigated tree-ring growth and carbon isotopes of the long-lived and high biomass Fitzroya cupressoides in two stands growing in contrasting environmental conditions in the Coastal Range (~300 years old) and Andean Cordilleras (>1500 years old) of southern Chile. The interannual variability in δ13C was assessed for the period 1800-2010, and changes in discrimination and intrinsic water use efficiency (iWUE) were evaluated in relation to changes in climate and tree-ring growth during the last century. 13C discrimination has significantly decreased, and iWUE has increased since the 1900s in both sites. However, these trends in isotopic composition have been accompanied by different growth patterns: decreasing growth rates in the Coastal Range since the 1970s and increasing growth rates in the Andes since the 1900s. Trees growing in the Coastal Range have become more efficient in their use of water, probably due to reduced stomatal conductance caused by increases in CO2 and warming. Trees growing in the Andes have also become more water use efficient, but this has been likely due to increased photosynthetic rates. Fitzroya forests, including particularly old-growth stands, are responding to recent environmental changes, and their response has been site dependent. The growth of forests under a more Mediterranean climate influence and restrictive soil conditions in the Coastal Range has been more negatively affected by current warming and drying; while the growth of old stands in the wet Andes has been positively affected by changes in climate (decreasing cloudiness) and increasing CO2. Permanent monitoring of these endangered forests under ongoing environmental changes is needed in order to reassure the long-term preservation of this millennial-aged species.

  3. [Spatial pattern analysis and associations of Quercus aquifolioides population at different growth stages in Southeast Tibet, China].

    PubMed

    Shen, Zhi-qiang; Hua, Min; Dan, Qu; Lu, Jie; Fang, Jiang-ping

    2016-02-01

    This article analyzed the spatial pattern and its correlation of Quercus aquifolioides, Southeast Tibet at different growing stages by using Ripley' s L function in the method of point pattern, analysis. The results showed the diameter structure of Q. aquifolioides population in Southeast Tibet followed a 'single peak' shape and the saplings and medium trees predominated in number in the whole population. The population had a high regeneration rate and was of increase type. In the growth process of Q. aquifolioides from saplings to large trees, saplings and medium trees showed aggregation distribution at.small scale, while large trees showed basically random distribution at whole scale. There was significant correlation between saplings with medium or large trees at small scale, however, there was no correlation between medium and large trees. In the growth process of Q. aquifolioides population from saplings, medium trees to large trees, its spatial pattern developed from aggregative distribution to random distribution. The natural regeneration of Q. aquifolioides population was affected not only by interspecific competition, but also by intraspecific competition. In the similar natural environment, the most important factors affecting the spatial pattern of Q. aquifoioides population were its own biological and ecological characteristics.

  4. Growth patterns of the slime mold Physarum on a nonuniform substrate

    NASA Astrophysics Data System (ADS)

    Halvorsrud, Ragnhild; Wagner, Geri

    1998-01-01

    The Myxomycete Physarum polycephalum has been grown on nonuniform substrates, where the nutrients were confined in separated drops of agar medium. Spatial and temporal aspects of the resulting growth structures were studied by time-lapse video techniques and analyzed using image processing software. The growth process on a linear substrate of drops can be described in terms of a searching phase alternating with a feeding phase. On a linear array of drops, the Physarum advanced uniformly after an initial lag phase. On a two-dimensional drop substrate two different growth regimes could be distinguished: branched growth was observed on substrates with small drop diameters and compact growth, similar to growth on uniform substrates, was observed on substrates with larger drop diameters. The drop size is a crucial parameter that mediates characteristic plasmodial morphologies. A crossover from branched to compact growth was observed in some of the experiments. A spatial correlation function was used that could quantitatively distinguish between the different growth regimes.

  5. Enhancing search efficiency by means of a search filter for finding all studies on animal experimentation in PubMed.

    PubMed

    Hooijmans, Carlijn R; Tillema, Alice; Leenaars, Marlies; Ritskes-Hoitinga, Merel

    2010-07-01

    Collecting and analysing all available literature before starting an animal experiment is important and it is indispensable when writing a systematic review (SR) of animal research. Writing such review prevents unnecessary duplication of animal studies and thus unnecessary animal use (Reduction). One of the factors currently impeding the production of 'high-quality' SRs in laboratory animal science is the fact that searching for all available literature concerning animal experimentation is rather difficult. In order to diminish these difficulties, we developed a search filter for PubMed to detect all publications concerning animal studies. This filter was compared with the method most frequently used, the PubMed Limit: Animals, and validated further by performing two PubMed topic searches. Our filter performs much better than the PubMed limit: it retrieves, on average, 7% more records. Other important advantages of our filter are that it also finds the most recent records and that it is easy to use. All in all, by using our search filter in PubMed, all available literature concerning animal studies on a specific topic can easily be found and assessed, which will help in increasing the scientific quality and thereby the ethical validity of animal experiments.

  6. Regularly patterned multi-section GaN nanorod arrays grown with a pulsed growth technique.

    PubMed

    Tu, Charng-Gan; Su, Chia-Ying; Liao, Che-Hao; Hsieh, Chieh; Yao, Yu-Feng; Chen, Hao-Tsung; Lin, Chun-Han; Weng, Chi-Ming; Kiang, Yean-Woei; Yang, C C

    2016-01-15

    The growth of regularly patterned multi-section GaN nanorod (NR) arrays based on a pulsed growth technique with metalorganic chemical vapor deposition is demonstrated. Such an NR with multiple sections of different cross-sectional sizes is formed by tapering a uniform cross section to another through stepwise decreasing of the Ga supply duration to reduce the size of the catalytic Ga droplet. Contrast line structures are observed in either a scanning electron microscopy or transmission electron microscopy image of an NR. Such a contrast line-marker corresponds to a thin Ga-rich layer formed at the beginning of GaN precipitation of a pulsed growth cycle and illustrates the boundary between two successive growth cycles in pulsed growth. By analyzing the geometry variation of the contrast line-markers, the morphology evolution in the growth of a multi-section NR, including a tapering process, can be traced. Such a morphology variation is controlled by the size of the catalytic Ga droplet and its coverage range on the slant facets at the top of an NR. The comparison of emission spectra between single-, two-, and three-section GaN NRs with sidewall InGaN/GaN quantum wells indicates that a multi-section NR can lead to a significantly broader sidewall emission spectrum.

  7. Inter-dependent tissue growth and Turing patterning in a model for long bone development

    NASA Astrophysics Data System (ADS)

    Tanaka, Simon; Iber, Dagmar

    2013-10-01

    The development of long bones requires a sophisticated spatial organization of cellular signalling, proliferation, and differentiation programs. How such spatial organization emerges on the growing long bone domain is still unresolved. Based on the reported biochemical interactions we developed a regulatory model for the core signalling factors IHH, PTCH1, and PTHrP and included two cell types, proliferating/resting chondrocytes and (pre-)hypertrophic chondrocytes. We show that the reported IHH-PTCH1 interaction gives rise to a Schnakenberg-type Turing kinetics, and that inclusion of PTHrP is important to achieve robust patterning when coupling patterning and tissue dynamics. The model reproduces relevant spatiotemporal gene expression patterns, as well as a number of relevant mutant phenotypes. In summary, we propose that a ligand-receptor based Turing mechanism may control the emergence of patterns during long bone development, with PTHrP as an important mediator to confer patterning robustness when the sensitive Turing system is coupled to the dynamics of a growing and differentiating tissue. We have previously shown that ligand-receptor based Turing mechanisms can also result from BMP-receptor, SHH-receptor, and GDNF-receptor interactions, and that these reproduce the wildtype and mutant patterns during digit formation in limbs and branching morphogenesis in lung and kidneys. Receptor-ligand interactions may thus constitute a general mechanism to generate Turing patterns in nature.

  8. Superhydrophobic surfaces using selected zinc oxide microrod growth on ink-jetted patterns.

    PubMed

    Myint, Myo Tay Zar; Kitsomboonloha, Rungrot; Baruah, Sunandan; Dutta, Joydeep

    2011-02-15

    The synthesis and properties of superhydrophobic surfaces based on binary surface topography made of zinc oxide (ZnO) microrod-decorated micropatterns are reported. ZnO is intrinsically hydrophilic but can be utilized to create hydrophobic surfaces by creating artificial roughness via microstructuring. Micron scale patterns consisting of nanocrystalline ZnO seed particles were applied to glass substrates with a modified ink-jet printer. Microrods were then grown on the patterns by a hydrothermal process without any further chemical modification. Water contact angle (WCA)(1) up to 153° was achieved. Different micro array patterned surfaces with varying response of static contact angle or sessile droplet analysis are reported.

  9. Trends and topics in eye disease research in PubMed from 2010 to 2014

    PubMed Central

    Denion, Eric; Mortemousque, Bruno; Mouriaux, Fréderic

    2016-01-01

    Background: The purpose of this study is to provide a report on scientific production during the period 2010–2014 in order to identify the major topics as well as the predominant actors (journals, countries, continents) involved in the field of eye disease. Methods: A PubMed search was carried out to extract articles related to eye diseases during the period 2010–2014. Data were downloaded and processed through developed PHP scripts for further analysis. Results: A total of 62,123 articles were retrieved. A total of 3,368 different journals were found, and 19 journals were identified as “core journals” according to Braford’s law. English was by far the predominant language. A total of 853,182 MeSH terms were found, representing an average of 13.73 (SD = 4.98) MeSH terms per article. Among these 853,182 MeSH terms, 14,689 different MeSH terms were identified. Vision Disorders, Glaucoma, Diabetic Retinopathy, Macular Degeneration, and Cataract were the most frequent five MeSH terms related to eye diseases. The analysis of the total number of publications showed that Europe and Asia were the most productive continents, and the USA and China the most productive countries. Interestingly, using the mean Five-Year Impact Factor, the two most productive continents were North America and Oceania. After adjustment for population, the overall ranking positions changed in favor of smaller countries (i.e. Iceland, Switzerland, Denmark, and New Zealand), while after adjustment for Gross Domestic Product (GDP), the overall ranking positions changed in favor of some developing countries (Malawi, Guatemala, Singapore). Conclusions: Due to the large number of articles included and the numerous parameters analyzed, this study provides a wide view of scientific productivity related to eye diseases during the period 2010–2014 and allows us to better understand this field. PMID:26819840

  10. Microtask crowdsourcing for disease mention annotation in PubMed abstracts.

    PubMed

    Good, Benjamin M; Nanis, Max; Wu, Chunlei; Su, Andrew I

    2015-01-01

    Identifying concepts and relationships in biomedical text enables knowledge to be applied in computational analyses. Many biological natural language processing (BioNLP) projects attempt to address this challenge, but the state of the art still leaves much room for improvement. Progress in BioNLP research depends on large, annotated corpora for evaluating information extraction systems and training machine learning models. Traditionally, such corpora are created by small numbers of expert annotators often working over extended periods of time. Recent studies have shown that workers on microtask crowdsourcing platforms such as Amazon's Mechanical Turk (AMT) can, in aggregate, generate high-quality annotations of biomedical text. Here, we investigated the use of the AMT in capturing disease mentions in PubMed abstracts. We used the NCBI Disease corpus as a gold standard for refining and benchmarking our crowdsourcing protocol. After several iterations, we arrived at a protocol that reproduced the annotations of the 593 documents in the 'training set' of this gold standard with an overall F measure of 0.872 (precision 0.862, recall 0.883). The output can also be tuned to optimize for precision (max = 0.984 when recall = 0.269) or recall (max = 0.980 when precision = 0.436). Each document was completed by 15 workers, and their annotations were merged based on a simple voting method. In total 145 workers combined to complete all 593 documents in the span of 9 days at a cost of $.066 per abstract per worker. The quality of the annotations, as judged with the F measure, increases with the number of workers assigned to each task; however minimal performance gains were observed beyond 8 workers per task. These results add further evidence that microtask crowdsourcing can be a valuable tool for generating well-annotated corpora in BioNLP. Data produced for this analysis are available at http://figshare.com/articles/Disease_Mention_Annotation_with_Mechanical_Turk/1126402.

  11. Species-specific effect of UV-B radiation on the temporal pattern of leaf growth.

    PubMed

    Robson, Thomas Matthew; Aphalo, Pedro José

    2012-02-01

    Recent molecular and physiological studies have demonstrated that ultraviolet-B radiation (UV-B) can affect some of the processes involved in leaf growth, but the phases of leaf growth affected have not been clearly delimited. We used functional growth analysis to assess the effects of UV-B radiation on the time course of leaf growth in seedlings of two birch species (Betula pendula and Betula pubescens). Our aim was to identify the phase(s) of leaf development affected by UV-B radiation. In a greenhouse study, 1-year-old birch seedlings were subjected to three daily doses of supplemental UV-B radiation treatments (UV-B⁺) and no UV-B radiation controls (UV-B⁻). Leaf growth measurements every 2 days were complemented by assessment of other functional traits over a 4-week period at the start of the growing season. Using fitted curves, we were able to determine that the rate of leaf expansion was slowed by the UV-B⁺ treatment in leaves of B. pendula because of a slower maximum leaf growth rate compared with plants under the UV-B⁻ controls, but that compensation toward the end of the period of expansion negated this difference when leaves reached their final size. UV-B⁺ had little effect on the rate of B. pubescens leaf growth despite a larger reduction in leaf final size due to UV-B⁺ than occurred in B. pendula leaves. In conclusion, effective regulation ameliorated the effects of UV-B radiation on leaf and seedling growth in B. pendula, whereas in B. pubescens, reductions in leaf final size under UV-B⁺ were consistent with a slightly reduced rate of height growth.

  12. Environmental control of daily stem growth patterns in five temperate broad-leaved tree species.

    PubMed

    Köcher, Paul; Horna, Viviana; Leuschner, Christoph

    2012-08-01

    Tree ring analysis investigates growth processes at time horizons of several weeks to millennia, but lacks the detail of short-term fluctuation in cambial activity. This study used electronic high-precision dendrometry for analyzing the environmental factors controlling stem diameter variation and radial growth in daily resolution in five co-existing temperate broad-leaved tree species (genera Fraxinus, Acer, Carpinus, Tilia and Fagus) with different growth and survival strategies. Daily stem radius change (SRC(d)) was primarily influenced by the atmospheric demand for water vapor (expressed either as vapor pressure deficit (D) or relative air humidity (RH)) while rainfall, soil matrix potential, temperature and radiation were only secondary factors. SRC(d) increased linearly with increasing RH and decreasing D in all species. The positive effect of a low atmospheric water vapor demand on SRC(d) was largest in June during the period of maximal radial growth rate and persisted when observation windows of 7 or 21 days instead of 1 day were used. We found a high synchronicity in the day-to-day growth rate fluctuation among the species with increment peaks corresponding to air humidity maxima, even though the mean daily radial growth rate differed fivefold among the species. The five -species also differed in the positive slope of the growth/RH relationship with the steepest increase found in Fraxinus and the lowest in Fagus. We explain the strong positive effect of high RH and low D on radial stem increment by lowered transpiration which reduces negative pressure in the conducting system and increases turgor in the stem cambium cells, thereby favoring cell division and expansion. The results suggest that mechanistic models of tree growth need to consider the atmospheric water status in addition to the known controlling environmental factors: temperature, soil moisture and precipitation. The results further have implications for sensitivity analyses of tree growth to

  13. Long-term patterns in estuarine fish growth across two climatically divergent regions.

    PubMed

    Doubleday, Zoë A; Izzo, Christopher; Haddy, James A; Lyle, Jeremy M; Ye, Qifeng; Gillanders, Bronwyn M

    2015-12-01

    Long-term ecological datasets are vital for investigating how species respond to changes in their environment, yet there is a critical lack of such datasets from aquatic systems. We developed otolith growth 'chronologies' to reconstruct the growth history of a temperate estuarine fish species, black bream (Acanthopagrus butcheri). Chronologies represented two regions in south-east Australia: South Australia, characterised by a relatively warm, dry climate, and Tasmania, characterised by a relatively cool, wet climate. Using a mixed modelling approach, we related inter-annual growth variation to air temperature, rainfall, freshwater inflow (South Australia only), and El Niño-Southern Oscillation events. Otolith chronologies provided a continuous record of growth over a 13- and 21-year period for fish from South Australia and Tasmania, respectively. Even though fish from Tasmania were sourced across multiple estuaries, they showed higher levels of growth synchronicity across years, and greater year-to-year growth variation, than fish from South Australia, which were sourced from a single, large estuary. Growth in Tasmanian fish declined markedly over the time period studied and was negatively correlated to temperature. In contrast, growth in South Australian fish was positively correlated to both temperature and rainfall. The stark contrast between the two regions suggests that Tasmanian black bream populations are more responsive to regional scale environmental variation and may be more vulnerable to global warming. This study highlights the importance of examining species response to climate change at the intra-specific level and further validates the emerging use of growth chronologies for generating long-term ecological data in aquatic systems. PMID:26245148

  14. Long-term patterns in estuarine fish growth across two climatically divergent regions.

    PubMed

    Doubleday, Zoë A; Izzo, Christopher; Haddy, James A; Lyle, Jeremy M; Ye, Qifeng; Gillanders, Bronwyn M

    2015-12-01

    Long-term ecological datasets are vital for investigating how species respond to changes in their environment, yet there is a critical lack of such datasets from aquatic systems. We developed otolith growth 'chronologies' to reconstruct the growth history of a temperate estuarine fish species, black bream (Acanthopagrus butcheri). Chronologies represented two regions in south-east Australia: South Australia, characterised by a relatively warm, dry climate, and Tasmania, characterised by a relatively cool, wet climate. Using a mixed modelling approach, we related inter-annual growth variation to air temperature, rainfall, freshwater inflow (South Australia only), and El Niño-Southern Oscillation events. Otolith chronologies provided a continuous record of growth over a 13- and 21-year period for fish from South Australia and Tasmania, respectively. Even though fish from Tasmania were sourced across multiple estuaries, they showed higher levels of growth synchronicity across years, and greater year-to-year growth variation, than fish from South Australia, which were sourced from a single, large estuary. Growth in Tasmanian fish declined markedly over the time period studied and was negatively correlated to temperature. In contrast, growth in South Australian fish was positively correlated to both temperature and rainfall. The stark contrast between the two regions suggests that Tasmanian black bream populations are more responsive to regional scale environmental variation and may be more vulnerable to global warming. This study highlights the importance of examining species response to climate change at the intra-specific level and further validates the emerging use of growth chronologies for generating long-term ecological data in aquatic systems.

  15. Environmental control of daily stem growth patterns in five temperate broad-leaved tree species.

    PubMed

    Köcher, Paul; Horna, Viviana; Leuschner, Christoph

    2012-08-01

    Tree ring analysis investigates growth processes at time horizons of several weeks to millennia, but lacks the detail of short-term fluctuation in cambial activity. This study used electronic high-precision dendrometry for analyzing the environmental factors controlling stem diameter variation and radial growth in daily resolution in five co-existing temperate broad-leaved tree species (genera Fraxinus, Acer, Carpinus, Tilia and Fagus) with different growth and survival strategies. Daily stem radius change (SRC(d)) was primarily influenced by the atmospheric demand for water vapor (expressed either as vapor pressure deficit (D) or relative air humidity (RH)) while rainfall, soil matrix potential, temperature and radiation were only secondary factors. SRC(d) increased linearly with increasing RH and decreasing D in all species. The positive effect of a low atmospheric water vapor demand on SRC(d) was largest in June during the period of maximal radial growth rate and persisted when observation windows of 7 or 21 days instead of 1 day were used. We found a high synchronicity in the day-to-day growth rate fluctuation among the species with increment peaks corresponding to air humidity maxima, even though the mean daily radial growth rate differed fivefold among the species. The five -species also differed in the positive slope of the growth/RH relationship with the steepest increase found in Fraxinus and the lowest in Fagus. We explain the strong positive effect of high RH and low D on radial stem increment by lowered transpiration which reduces negative pressure in the conducting system and increases turgor in the stem cambium cells, thereby favoring cell division and expansion. The results suggest that mechanistic models of tree growth need to consider the atmospheric water status in addition to the known controlling environmental factors: temperature, soil moisture and precipitation. The results further have implications for sensitivity analyses of tree growth to

  16. Direct growth and patterning of multilayer graphene onto a targeted substrate without an external carbon source.

    PubMed

    Kang, Dongseok; Kim, Won-Jun; Lim, Jung Ah; Song, Yong-Won

    2012-07-25

    Using only a simple tube furnace, we demonstrate the synthesis of patterned graphene directly on a designed substrate without the need for an external carbon source. Carbon atoms are absorbed onto Ni evaporator sources as impurities, and incorporated into catalyst layers during the deposition. Heat treatment conditions were optimized so that the atoms diffused out along the grain boundaries to form nanocrystals at the catalyst-substrate interfaces. Graphene patterns were obtained under patterned catalysts, which restricted graphene formation to within patterned areas. The resultant multilayer graphene was characterized by Raman spectroscopy and transmission electron microscopy to verify the high crystallinity and two-dimensional nanomorphology. Finally, a metal-semiconductor diode with a catalyst-graphene contact structure were fabricated and characterized to assess the semiconducting properties of the graphene sheets with respect to the display of asymmetric current-voltage behavior.

  17. Age and growth patterns in Channa marulius from Harike Wetland (A Ramsar site), Punjab, India.

    PubMed

    Dua, Anish; Kumar, Kanwaljit

    2006-05-01

    Scale samples of Channa marulius were collected and studied for age determination and calculation of growth parameters. The fish were sampled from Harike Wetland during 1998 to 1999. Linear relationship with a high degree of correlation was observed between total fish length and the lateral scale radius. Age determination studies revealed 5 age groups. The harvestable size falls just below the 2nd year. The regression equation is given. Various growth parameters indicate a hardy nature of the fish and the suitability of habitat ecology for its optimum growth. PMID:17436527

  18. Developmental growth patterns of the filter-feeder pterosaur, Pterodaustro guiñazui.

    PubMed

    Chinsamy, A; Codorniú, L; Chiappe, L

    2008-06-23

    Life-history parameters of pterosaurs such as growth and ontogenetic development represent an enigma. This aspect of pterosaur biology has remained perplexing because few pterosaur taxa are represented by complete ontogenetic series. Of these, Pterodaustro is unique in that besides being represented by hundreds of individuals with wing spans ranging from 0.3 to 2.5m, it includes an embryo within an egg. Here we present a comprehensive osteohistological assessment of multiple skeletal elements of a range of ontogenetic sizes of Pterodaustro, and we provide unparalleled insight into its growth dynamics. We show that, upon hatching, Pterodaustro juveniles grew rapidly for approximately 2 years until they reached approximately 53% of their mature body size, whereupon they attained sexual maturity. Thereafter, growth continued for at least another 3-4 years at comparatively slower rates until larger adult body sizes were attained. Our analysis further provides definitive evidence that Pterodaustro had a determinate growth strategy.

  19. Direct evidences on bacterial growth pattern regulating pyrene degradation pathway and genotypic dioxygenase expression.

    PubMed

    Chen, Baowei; Huang, Jinyin; Yuan, Ke; Lin, Li; Wang, Xiaowei; Yang, Lihua; Luan, Tiangang

    2016-04-15

    Pyrene degradation by Mycobacterium sp. strain A1-PYR was investigated in the presence of nutrient broth, phenanthrene and fluoranthene, respectively. Fast bacterial growth in the nutrient broth considerably enhanced pyrene degradation rate, whereas degradation efficiency per cell was substantially decreased. The addition of nutrient broth could not alter the transcription levels of all dioxygenase genotypes. In the PAH-only substrates, bacterial growth completely relied on biological conversion of PAHs into the effective carbon sources, which led to a higher degradation efficiency of pyrene per cell than the case of nutrient broth. Significant correlations were only observed between nidA-related dioxygenase expression and pyrene degradation or bacterial growth. The highest pyrene degradation rate in the presence of phenanthrene was consistent with the highest transcription level of nidA and 4,5-pyrenediol as the sole initial metabolite. This study reveals that bacterial growth requirement can invigorate degradation of PAHs by regulating metabolic pathway and genotypic enzyme expression.

  20. Growth and patterning are evolutionarily dissociated in the vestigial wing discs of workers of the red imported fire ant, Solenopsis invicta.

    PubMed

    Bowsher, Julia H; Wray, Gregory A; Abouheif, Ehab

    2007-12-15

    Over the last decade, it has become clear that organismal form is largely determined by developmental and evolutionary changes in the growth and pattern formation of tissues. Yet, there is little known about how these two integrated processes respond to environmental cues or how they evolve relative to one another. Here, we present the discovery of vestigial wing imaginal discs in worker larvae of the red imported fire ant, Solenopsis invicta. These vestigial wing discs are present in all worker larvae, which is uncommon for a species with a large worker size distribution. Furthermore, the growth trajectory of these vestigial discs is distinct from all of the ant species examined to date because they grow at a rate slower than the leg discs. We predicted that the growth trajectory of the vestigial wing discs would be mirrored by evolutionary changes in their patterning. We tested this prediction by examining the expression of three patterning genes, extradenticle, ultrabithorax, and engrailed, known to underlie the wing polyphenism in ants. Surprisingly, the expression patterns of these three genes in the vestigial wing discs was the same as those found in ant species with different worker size distributions and wing disc growth than fire ants. We conclude that growth and patterning are evolutionarily dissociated in the vestigial wing discs of S. invicta because patterning in these discs is conserved, whereas their growth trajectories are not. The evolutionary dissociation of growth and patterning may be an important feature of gene networks that underlie polyphenic traits.

  1. Error growth patterns in systems with spatial chaos: from coupled map lattices to global weather models.

    PubMed

    Primo, C; Szendro, I G; Rodríguez, M A; Gutiérrez, J M

    2007-03-01

    Error growth in spatiotemporal chaotic systems is investigated by analyzing the interplay between temporal and spatial dynamics. The spatial correlation and localization of relative fluctuations grow and decay indicating two different regimes, before and after saturation by nonlinear effects. This general behavior is shown to hold both in simple coupled map lattices and in global weather models. This explains the increasing or decreasing trends previously observed in the exponential growth rate of these spatiotemporal systems.

  2. Patterned poly(lactic acid) films support growth and spontaneous multilineage gene expression of adipose-derived stem cells.

    PubMed

    Foldberg, Steffan; Petersen, Morten; Fojan, Peter; Gurevich, Leonid; Fink, Trine; Pennisi, Cristian P; Zachar, Vladimir

    2012-05-01

    Conventional culture surfaces do not provide optimal environmental cues for expansion or differentiation of adult stem cells. Aiming to increase the efficiency of the in vitro culture conditions, biocompatible and biodegradable biomaterials such as poly(lactic acid) (PLA) have been proposed to engineer the stem cell microenvironment. In this study, we explored the feasibility of using PLA substrates to control the responses of adipose-derived stem cells (ASCs). The substrates consisted of flat and patterned PLA films fabricated by casting a chloroform-PLA solution on a glass surface. Patterning was achieved through the condensation of nano-sized water droplets during chloroform evaporation, which resulted in films displaying irregularly distributed circular indentations with a mean diameter of 248±65 nm. Both types of PLA substrates were assessed for protein adsorption using fibronectin and in vitro cell culturing. Tissue-culture polystyrene (TCPS) plates were used as control surfaces. The experiments demonstrated that the patterned PLA substrates had a significantly higher fibronectin adsorption capacity when compared with the flat counterparts. For the entire duration of the culture period, there was no significant difference in cell growth rate on the PLA surfaces with respect to TCPS despite signs of reduced adhesion. In addition, the semi-quantitative real-time RT-PCR analysis of a set of 14 lineage-specific genes revealed that the PLA-related transcriptional activity significantly surpassed that of TCPS. Remarkably, when assessing the effect of patterning, the patterned films proved superior regarding the activation of genes involved in the skeletal myogenic, cardiomyogenic, chondrogenic, and adipogenic pathways. Taken together, our data provide evidence that the surface patterning can exert such an influence on the stem cell microenvironment that the differentiation process can be effectively modulated. Consequently, the patterned PLA surfaces could

  3. Seasonal and spatial patterns of growth of rainbow trout in the Colorado River in Grand Canyon, AZ

    USGS Publications Warehouse

    Yard, Micheal D.; Korman, Josh; Walters, Carl J.; Kennedy, T.A.

    2016-01-01

    Rainbow trout (Oncorhynchus mykiss) have been purposely introduced in many regulated rivers, with inadvertent consequences on native fishes. We describe how trout growth rates and condition could be influencing trout population dynamics in a 130 km section of the Colorado River below Glen Canyon Dam based on a large-scale mark–recapture program where ∼8000 rainbow trout were recaptured over a 3-year period (2012–2014). There were strong temporal and spatial variations in growth in both length and weight as predicted from von Bertalanffy and bioenergetic models, respectively. There was more evidence for seasonal variation in the growth coefficient and annual variation in the asymptotic length. Bioenergetic models showed more variability for growth in weight across seasons and years than across reaches. These patterns were consistent with strong seasonal variation in invertebrate drift and effects of turbidity on foraging efficiency. Highest growth rates and relative condition occurred in downstream reaches with lower trout densities. Results indicate that reduction in rainbow trout abundance in Glen Canyon will likely increase trout size in the tailwater fishery and may reduce downstream dispersal into Grand Canyon.

  4. Growth patterns of Angus, Charolais, Charolais X Angus and Holstein X Angus cows from birth to maturity.

    PubMed

    Nadarajah, K; Marlowe, T J; Notter, D R

    1984-10-01

    Growth patterns of 182 cows [73 Angus (AA), 31 Charolais (CC), 38 Charolais X Angus (CA) and 40 Holstein X Angus (FA)] were studied from birth to maturity. Breed type significantly affected weight and condition at all ages. Crossbred cows were heavier than AA and lighter in weight than CC cows (P less than .01) at all periods. Differences between CA and FA cows were small. The CA cows were somewhat heavier than FA cows, but when weight was adjusted for condition, these two groups reversed rank at 56 and 68 mo. Differences in weight among breed types increased from birth to 44 mo and stabilized thereafter. Weights at early ages were influenced more by environmental effects than were weights at later ages. Adjustment for condition significantly reduced phenotypic variation in weight at all ages. Two growth models (Brody and Richards) were fitted to the weight-age data for each breed type. Differences in growth were expressed in terms of differences in mature weight and maturing rate. The AA cows were smallest at maturity and matured most rapidly; CC cows were largest and matured least rapidly. The FA and CA cows were intermediate and similar in mature size and maturing rate. Crossbreeding may have increased maturing rate somewhat when weights were not adjusted for condition. The four-parameter Richards model did not provide an appreciably better fit to the data than the three-parameter Brody model, and both models described early growth less adequately than later growth.

  5. Growth Pattern Responses to Photoperiod across Latitudes in a Northern Damselfly

    PubMed Central

    Śniegula, Szymon; Nilsson-Örtman, Viktor; Johansson, Frank

    2012-01-01

    Background Latitudinal clines in temperature and seasonality impose strong seasonal constraints on ectotherms. Studies of population differentiation in phenotypic plasticity of life history traits along latitudinal gradients are important for understanding how organisms have adapted to seasonal environments and predict how they respond to climate changes. Such studies have been scarce for species with a northern distribution. Methodology/Principle Finding Larvae of the northern damselfly Coenagrion johanssoni originating from semivoltine central, partivoltine northern, and partivoltine northernmost Swedish populations were reared in the laboratory. To investigate whether larvae use photoperiodic cues to induce compensatory growth along this latitudinal gradient, larvae were reared under two different photoperiods corresponding to a northern and southern latitude. In addition, field adult size was assessed to test the strength of possible compensatory growth mechanisms under natural conditions and hatchling size was measured to test for maternal effects. We hypothesized that populations originating from lower latitudes would be more time constrained than high-latitude populations because they have a shorter life cycle. The results showed that low-latitude populations had higher growth rates in summer/fall. In general northern photoperiods induced higher growth rates, but this plastic response to photoperiod was strongest in the southernmost populations and negligible in the northernmost population. During spring, central populations grew faster under the southern rather than the northern photoperiod. On the other hand, northern and northernmost populations did not differ between each other and grew faster in the northern rather than in the southern photoperiod. Field sampled adults did not differ in size across the studied regions. Conclusion/Significance We found a significant differentiation in growth rate across latitudes and latitudinal difference in growth rate

  6. Preferential growth orientation of laser-patterned LiNbO{sub 3} crystals in lithium niobium silicate glass

    SciTech Connect

    Komatsu, T.; Koshiba, K.; Honma, T.

    2011-02-15

    Dots and lines consisting of LiNbO{sub 3} crystals are patterned on the surface of 1CuO-40Li{sub 2}O-32Nb{sub 2}O{sub 5}-28SiO{sub 2} (mole ratio) glass by irradiations of continuous-wave Nd:YAG laser (wavelength: {lambda}=1064 nm), diode laser ({lambda}=795 nm), and Yb:YVO{sub 4} fiber laser ({lambda}=1080 nm), and the feature of laser-patterned LiNbO{sub 3} crystal growth is examined from linearly polarized micro-Raman scattering spectrum measurements. LiNbO{sub 3} crystals with the c-axis orientation are formed at the edge parts of the surface and cross-section of dots. The growth direction of an LiNbO{sub 3} along the laser scanning direction is the c-axis. It is proposed that the profile of the temperature distribution in the laser-irradiated region and its change along laser scanning would be one of the most important conditions for the patterning of crystals with a preferential growth orientation. Laser irradiation giving a narrow width is also proposed to be one of the important factors for the patterning of LiNbO{sub 3} crystal lines with homogeneous surface morphologies. -- Graphical abstract: Polarized optical microscope observations for the surface and cross-section of the dot obtained by LD laser ({lambda}=795 nm) irradiations of P=1.4 W and t=20 s in Cu-LNS glass. Schematic model for the orientation of LiNbO{sub 3} crystals at the edge parts of the surface and cross-section of the dot is also shown. Display Omitted Research highlights: > Dots and lines with LiNbO{sub 3} crystals are patterned on the glass surface by laser irradiations. > LiNbO{sub 3} crystals with the c-axis orientation are formed at the edge parts of the surface and cross-section of dots. > The profile of the temperature distribution in the laser-irradiated region is one of the most important conditions for the patterning of highly oriented crystals.

  7. Understanding the growth rate patterns of ion Bernstein instabilities driven by ring-like proton velocity distributions

    NASA Astrophysics Data System (ADS)

    Min, Kyungguk; Liu, Kaijun

    2016-04-01

    Fast magnetosonic waves in Earth's inner magnetosphere, which have as their source ion Bernstein instabilities, are driven by hot proton velocity distributions (fp) with ∂fp(v⊥)/∂v⊥>0. Two typical types of distributions with such features are ring and shell velocity distributions. Both have been used in studies of ion Bernstein instabilities and fast magnetosonic waves, but the differences between instabilities driven by the two types of distributions have not been thoroughly addressed. The present study uses linear kinetic theory to examine and understand these differences. It is found that the growth rate pattern is primarily determined by the cyclotron resonance condition and the structure of the velocity distribution in gyroaveraged velocity space. For ring-driven Bernstein instabilities, as the parallel wave number (k∥) increases, the discrete unstable modes approximately follow the corresponding proton cyclotron harmonic frequencies while they become broader in frequency space. At sufficiently large k∥, the neighboring discrete modes merge into a continuum. In contrast, for shell-driven Bernstein instabilities, the curved geometry of the shell velocity distribution in gyroaveraged velocity space results in a complex alternating pattern of growth and damping rates in frequency and wave number space and confines the unstable Bernstein modes to relatively small k∥. In addition, when k∥ increases, the unstable modes are no longer limited to the proton cyclotron harmonic frequencies. The local growth rate peak near an exact harmonic at small k∥ bifurcates into two local peaks on both sides of the harmonic when k∥ becomes large.

  8. Investigation of Growth Patterns due to Environmental Factors on the Surface of Bivalve shells with LIBS and Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Palmer, Andria; Mays, Joseph; Amos, James; Dynka, Tom; Ujj, Laszlo

    Environmental disturbances (such as temperature or chemical disturbances) can cause bivalve mollusk shells to grow faster or slower and cause changes in color and surface ring pattern. We have selected a few shells from our local habitat in Pensacola Beach, FL to analyze without sample treatment to determine what factors may have come into play during growth and use this as a way to analyze our marine environment. Laser Induced Breakdown Spectroscopy (LIBS) uses high energy laser pulses (355 and 532nm) to ablate the sample and create a micro-plasma from which emission spectra can be recorded. Based upon the analysis of intensities, wavelengths, and band patterns of spectral emission bands, the spatial qualitative elemental composition of the shell samples can be determined. Raman spectra were also recorded and correlated to molecules in the sample. By analyzing these measurements using LIBS-Raman spectroscopic techniques, we will be able to see how the local environment is effecting growth, with the largest chemical disturbance in the area being the BP Oil Spill in the Gulf in 2010. Therefore if samples are selected from this period of time it may be possible to identify the effects on shell growth. UWF NIH MARC U-STAR 1T34GM110517-01, UWF Office of Undergraduate Research.

  9. Observations of pore-scale growth patterns of carbon dioxide hydrate using X-ray computed microtomography

    NASA Astrophysics Data System (ADS)

    Ta, Xuan Hien; Yun, Tae Sup; Muhunthan, Balasingam; Kwon, Tae-Hyuk

    2015-03-01

    Natural and artificial gas hydrates with internal pores of nano to centimeters and weak grain-cementation have been widely reported, while the detailed formation process of grain-cementing hydrates remains poorly identified. Pore-scale morphology of carbon dioxide (CO2) hydrate formed in a partially brine-saturated porous medium was investigated via X-ray computed microtomography (X-ray CMT). Emphasis is placed on the pore-scale growth patterns of gas hydrate, including the growth of dendritic hydrate crystals on preformed hydrate and water-wetted grains, porous nature of the hydrate phase, volume expansion of more than 200% during the water-to-hydrate phase transformation, preference of unfrozen water wetting hydrophilic minerals, and the relevance to a weak cementation effect on macroscale physical properties. The presented pore-scale morphology and growth patterns of gas hydrate are expected in natural sediment settings where free gas is available for hydrate formation, such as active gas vents, gas seeps, mud volcanoes, permafrost gas hydrate provinces, and CO2 injected formation for the sake of geologic carbon storage; and in laboratory hydrate samples synthesized from partially brine-saturated sediments or formed from water-gas interfaces.

  10. Strain-induced growth instability and nanoscale surface patterning in perovskite thin films

    PubMed Central

    Pandya, Shishir; Damodaran, Anoop R.; Xu, Ruijuan; Hsu, Shang-Lin; Agar, Joshua C.; Martin, Lane W.

    2016-01-01

    Despite extensive studies on the effects of epitaxial strain on the evolution of the lattice and properties of materials, considerably less work has explored the impact of strain on growth dynamics. In this work, we demonstrate a growth-mode transition from 2D-step flow to self-organized, nanoscale 3D-island formation in PbZr0.2Ti0.8O3/SrRuO3/SrTiO3 (001) heterostructures as the kinetics of the growth process respond to the evolution of strain. With increasing heterostructure thickness and misfit dislocation formation at the buried interface, a periodic, modulated strain field is generated that alters the adatom binding energy and, in turn, leads to a kinetic instability that drives a transition from 2D growth to ordered, 3D-island formation. The results suggest that the periodically varying binding energy can lead to inhomogeneous adsorption kinetics causing preferential growth at certain sites. This, in conjunction with the presence of an Ehrlich-Schwoebel barrier, gives rise to long-range, periodically-ordered arrays of so-called “wedding cake” 3D nanostructures which self-assemble along the [100] and [010]. PMID:27194595

  11. Strain-induced growth instability and nanoscale surface patterning in perovskite thin films

    NASA Astrophysics Data System (ADS)

    Pandya, Shishir; Damodaran, Anoop R.; Xu, Ruijuan; Hsu, Shang-Lin; Agar, Joshua C.; Martin, Lane W.

    2016-05-01

    Despite extensive studies on the effects of epitaxial strain on the evolution of the lattice and properties of materials, considerably less work has explored the impact of strain on growth dynamics. In this work, we demonstrate a growth-mode transition from 2D-step flow to self-organized, nanoscale 3D-island formation in PbZr0.2Ti0.8O3/SrRuO3/SrTiO3 (001) heterostructures as the kinetics of the growth process respond to the evolution of strain. With increasing heterostructure thickness and misfit dislocation formation at the buried interface, a periodic, modulated strain field is generated that alters the adatom binding energy and, in turn, leads to a kinetic instability that drives a transition from 2D growth to ordered, 3D-island formation. The results suggest that the periodically varying binding energy can lead to inhomogeneous adsorption kinetics causing preferential growth at certain sites. This, in conjunction with the presence of an Ehrlich-Schwoebel barrier, gives rise to long-range, periodically-ordered arrays of so-called “wedding cake” 3D nanostructures which self-assemble along the [100] and [010].

  12. Temporal patterns in growth and survival of the round goby Neogobius melanostomus.

    PubMed

    Lynch, M P; Mensinger, A F

    2013-01-01

    Monthly, overwinter and annual instantaneous growth rates for round goby Neogobius melanostomus were calculated with maximal growth occurring in July and August and almost no growth observed between ice appearance (October) and melt (March). Annual absolute growth rates averaged 27·3 ± 1·9 mm for males and 19·8 ± 2·4 mm for females. The most parsimonious Cormack-Jolly-Seber model indicated that both the survival and recapture probabilities were dependent on sampling date, but not sex. Survival estimates remained high throughout the 13 month study with a median weekly survival probability of 0·920 (25 and 75% quartiles: 0·767 and 0·991), an overwinter survival probability of 99% and an annual survival rate of 67%. Survival probabilities were lowest for both sexes near the completion of the N. melanostomus reproductive season in July and August which supports existing evidence of higher mortality after reproduction, while challenging the paradigm that male N. melanostomus suffer comparatively higher mortality as a result of reproduction than females. Evidence indicating that growth and mortality rates are highest at the end of the reproductive season not only highlights seasonal variability in N. melanostomus natural history, but may also guide the control of this invasive species to periods when they are most vulnerable.

  13. Patterns of leaf and flower removal: Their effect on fruit growth in Chamaenerion angustifolium (fireweed)

    SciTech Connect

    Shea, M.M.; Watson, M.A. )

    1989-06-01

    The response of Chamaenerion angustifolium (fireweed) plants of different patterns of artificial leaf and flower herbivory was examined to determine if the effects of localized herbivory were confined within vertical sectors of the plant. The effect of leaf and flower removal on fruit development was compared for removals within sectors and distributed among sectors. Fruit development did not differ in plants subjected to different patterns of leaf and flower removal. These results suggest that in disturbed plants carbohydrate movement is not confined within vertical sectors.

  14. Differential Growth Patterns Among Healthy Infants Fed Protein Hydrolysate or Cow-Milk Formulas

    PubMed Central

    Ventura, Alison K.; Beauchamp, Gary K.

    2011-01-01

    OBJECTIVE: Infant formulas differ considerably in composition and sensory profiles. In this randomized study, we examined whether healthy infants fed an extensively protein hydrolysate formula (PHF) would differ in feeding behavior and growth from those fed cow-milk formula (CMF). PATIENTS AND METHODS: Infants were randomly assigned to be fed CMF or PHF between 0.5 and 7.5 months of age. Each month for 7 months, infants were weighed and measured and then videotaped while being fed their assigned formula. Anthropometric z scores were calculated by using World Health Organization growth standards. Multilevel linear growth and piecewise mixed-effects models compared trajectories for growth measures and formula acceptance. RESULTS: When compared with infants fed CMF, infants fed PHF had significantly lower weight-for-length z scores across ages 2.5 to 7.5 months. There were no differences in length-for-age z scores, which indicate that group differences resulted from gains in weight, not length. Infants fed PHF also had significantly slower weight gain velocity compared with infants fed CMF. During the monthly assessments, PHF-fed infants consumed less formula to satiation than did CMF-fed infants across the study period. Maternal ratings of infants' acceptance of the formula did not differ at any age. CONCLUSIONS: z-score trajectories indicate that CMF-fed infants' weight gain was accelerated, whereas PHF-fed infants' weight gain was normative. Whether such differences in growth are because of differences in the protein content or amino acid profile of the formulas and, in turn, metabolism is unknown. Research on the long-term consequences of these early growth differences is needed. PMID:21187303

  15. Living bacteria rheology: Population growth, aggregation patterns, and collective behavior under different shear flows

    NASA Astrophysics Data System (ADS)

    Patrício, P.; Almeida, P. L.; Portela, R.; Sobral, R. G.; Grilo, I. R.; Cidade, T.; Leal, C. R.

    2014-08-01

    The activity of growing living bacteria was investigated using real-time and in situ rheology—in stationary and oscillatory shear. Two different strains of the human pathogen Staphylococcus aureus—strain COL and its isogenic cell wall autolysis mutant, RUSAL9—were considered in this work. For low bacteria density, strain COL forms small clusters, while the mutant, presenting deficient cell separation, forms irregular larger aggregates. In the early stages of growth, when subjected to a stationary shear, the viscosity of the cultures of both strains increases with the population of cells. As the bacteria reach the exponential phase of growth, the viscosity of the cultures of the two strains follows different and rich behaviors, with no counterpart in the optical density or in the population's colony-forming units measurements. While the viscosity of strain COL culture keeps increasing during the exponential phase and returns close to its initial value for the late phase of growth, where the population stabilizes, the viscosity of the mutant strain culture decreases steeply, still in the exponential phase, remains constant for some time, and increases again, reaching a constant plateau at a maximum value for the late phase of growth. These complex viscoelastic behaviors, which were observed to be shear-stress-dependent, are a consequence of two coupled effects: the cell density continuous increase and its changing interacting properties. The viscous and elastic moduli of strain COL culture, obtained with oscillatory shear, exhibit power-law behaviors whose exponents are dependent on the bacteria growth stage. The viscous and elastic moduli of the mutant culture have complex behaviors, emerging from the different relaxation times that are associated with the large molecules of the medium and the self-organized structures of bacteria. Nevertheless, these behaviors reflect the bacteria growth stage.

  16. Selective growth of tilted ZnO nanoneedles and nanowires by PLD on patterned sapphire substrates

    NASA Astrophysics Data System (ADS)

    Shkurmanov, Alexander; Sturm, Chris; Lenzner, Jörg; Feuillet, Guy; Tendille, Florian; De Mierry, Philippe; Grundmann, Marius

    2016-09-01

    We report the possibility to control the tilting of nanoneedles and nanowires by using structured sapphire substrates. The advantage of the reported strategy is to obtain well oriented growth along a single direction tilted with respect to the surface normal, whereas the growth in other directions is suppressed. In our particular case, the nanostructures are tilted with respect to the surface normal by an angle of 58 ° . Moreover, we demonstrate that variation of the nanostructures shape from nanoneedles to cylindrical nanowires by using SiO2 layer is observed.

  17. HYDRAULIC REDISTRIBUTION OF SOIL WATER IN TWO OLD-GROWTH CONIFEROUS FORESTS: QUANTIFYING PATTERNS AND CONTROLS

    EPA Science Inventory

    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 sea...

  18. Shifting Sands: Science Researchers on Google Scholar, Web of Science, and PubMed, with Implications for Library Collections Budgets

    ERIC Educational Resources Information Center

    Hightower, Christy; Caldwell, Christy

    2010-01-01

    Science researchers at the University of California Santa Cruz were surveyed about their article database use and preferences in order to inform collection budget choices. Web of Science was the single most used database, selected by 41.6%. Statistically there was no difference between PubMed (21.5%) and Google Scholar (18.7%) as the second most…

  19. Public accessibility of biomedical articles from PubMed Central reduces journal readership--retrospective cohort analysis.

    PubMed

    Davis, Philip M

    2013-07-01

    Does PubMed Central--a government-run digital archive of biomedical articles--compete with scientific society journals? A longitudinal, retrospective cohort analysis of 13,223 articles (5999 treatment, 7224 control) published in 14 society-run biomedical research journals in nutrition, experimental biology, physiology, and radiology between February 2008 and January 2011 reveals a 21.4% reduction in full-text hypertext markup language (HTML) article downloads and a 13.8% reduction in portable document format (PDF) article downloads from the journals' websites when U.S. National Institutes of Health-sponsored articles (treatment) become freely available from the PubMed Central repository. In addition, the effect of PubMed Central on reducing PDF article downloads is increasing over time, growing at a rate of 1.6% per year. There was no longitudinal effect for full-text HTML downloads. While PubMed Central may be providing complementary access to readers traditionally underserved by scientific journals, the loss of article readership from the journal website may weaken the ability of the journal to build communities of interest around research papers, impede the communication of news and events to scientific society members and journal readers, and reduce the perceived value of the journal to institutional subscribers. PMID:23554455

  20. Public accessibility of biomedical articles from PubMed Central reduces journal readership--retrospective cohort analysis.

    PubMed

    Davis, Philip M

    2013-07-01

    Does PubMed Central--a government-run digital archive of biomedical articles--compete with scientific society journals? A longitudinal, retrospective cohort analysis of 13,223 articles (5999 treatment, 7224 control) published in 14 society-run biomedical research journals in nutrition, experimental biology, physiology, and radiology between February 2008 and January 2011 reveals a 21.4% reduction in full-text hypertext markup language (HTML) article downloads and a 13.8% reduction in portable document format (PDF) article downloads from the journals' websites when U.S. National Institutes of Health-sponsored articles (treatment) become freely available from the PubMed Central repository. In addition, the effect of PubMed Central on reducing PDF article downloads is increasing over time, growing at a rate of 1.6% per year. There was no longitudinal effect for full-text HTML downloads. While PubMed Central may be providing complementary access to readers traditionally underserved by scientific journals, the loss of article readership from the journal website may weaken the ability of the journal to build communities of interest around research papers, impede the communication of news and events to scientific society members and journal readers, and reduce the perceived value of the journal to institutional subscribers.

  1. An Evaluation of Upper and Lower Pharyngeal Airway Width, Tongue Posture and Hyoid Bone Position in Subjects with Different Growth Patterns

    PubMed Central

    Tarkar, Jaipal Singh; Parashar, Sandeep; Gupta, Garima; Bhardwaj, Preeti; Singh, Atul; Singh, Parul

    2016-01-01

    Introduction It is important to evaluate the position of the hyoid bone in relation to the tongue at the beginning of orthodontic treatment so that during the treatment, its position may be directed hence overall impact on airway could be assessed. Aim The aim of this study was to evaluate the upper and lower pharyngeal airway dimensions, posture of tongue and hyoid bone position in young adults with different growth patterns. Materials and Methods Sample size of the study included 90 post-adolescent subjects, within the age range of 18-32 years. Based on the different growth pattern of the face, subjects were divided into Group I (n=30; average growth pattern), Group II (n=30; horizontal growth pattern) and Group III (n=30; vertical growth pattern). Lateral cephalogram were traced and analysed manually by the same investigator for evaluation of upper and lower pharyngeal airway, tongue posture and hyoid bone position. The intergroup comparison of upper and lower pharyngeal airway dimensions, posture of tongue and hyoid bone was performed with one-way ANOVA test. Results The results showed that upper oropharyngeal widths were significantly different in different facial skeletal patterns (p=0.00). Subjects with vertical skeletal pattern have significantly narrower upper airways than those with horizontal skeletal pattern (p= 0.025). There was significantly higher difference in position of dorsum of the tongue in vertical growth pattern group (p=0.00). The hyoid bone was positioned farther from the mandibular symphysis in brachyfacial subjects, reflected by the larger H-RGN (Hyoid- retrognathion) values compared with the dolichofacial and normal subjects (p=0.044). Conclusion The upper oropharyngeal width was found to be narrower in subjects with vertical growth pattern. The dorsum of the tongue is seen to be placed higher in subjects with vertical growth pattern. The hyoid bone was more inferiorly and posteriorly positioned in subjects with horizontal growth pattern

  2. Algal morphogenesis: modelling interspecific variation in Micrasterias with reaction--diffusion patterned catalysis of cell surface growth

    PubMed Central

    Holloway, D. M.

    1999-01-01

    Semi-cell morphogenesis in unicellular desmid algae of the genus Micrasterias generates a stellar shape by repeated dichotomous branching of growing tips of the cell surface. The numerous species of the genus display variations of the branching pattern that differ markedly in number of branchings, lobe width and lobe length. We have modelled this morphogenesis, following previous work by D. M. Harrison and M. Kolar (1988), on the assumptions that patterning occurs by chemical reaction-diffusion activity within the plasma membrane, leading to morphological expression by patterned catalysis of the extension of the cell surface. The latter has been simulated in simplified form by two-dimensional computations. Our results indicate that for generation of repeated branchings and for the control of diverse species-specific shapes, the loss of patterning activity and of rapid growth in regions separating the active growing tips is an essential feature. We believe this conclusion to be much more general than the specific details of our model. We discuss the limitations of the model especially in terms of what extra features might be addressed in three-dimensional computation.

  3. Bayesian model selection framework for identifying growth patterns in filamentous fungi.

    PubMed

    Lin, Xiao; Terejanu, Gabriel; Shrestha, Sajan; Banerjee, Sourav; Chanda, Anindya

    2016-06-01

    This paper describes a rigorous methodology for quantification of model errors in fungal growth models. This is essential to choose the model that best describes the data and guide modeling efforts. Mathematical modeling of growth of filamentous fungi is necessary in fungal biology for gaining systems level understanding on hyphal and colony behaviors in different environments. A critical challenge in the development of these mathematical models arises from the indeterminate nature of their colony architecture, which is a result of processing diverse intracellular signals induced in response to a heterogeneous set of physical and nutritional factors. There exists a practical gap in connecting fungal growth models with measurement data. Here, we address this gap by introducing the first unified computational framework based on Bayesian inference that can quantify individual model errors and rank the statistical models based on their descriptive power against data. We show that this Bayesian model comparison is just a natural formalization of Occam׳s razor. The application of this framework is discussed in comparing three models in the context of synthetic data generated from a known true fungal growth model. This framework of model comparison achieves a trade-off between data fitness and model complexity and the quantified model error not only helps in calibrating and comparing the models, but also in making better predictions and guiding model refinements. PMID:27000772

  4. A diffusion process to model generalized von Bertalanffy growth patterns: fitting to real data.

    PubMed

    Román-Román, Patricia; Romero, Desirée; Torres-Ruiz, Francisco

    2010-03-01

    The von Bertalanffy growth curve has been commonly used for modeling animal growth (particularly fish). Both deterministic and stochastic models exist in association with this curve, the latter allowing for the inclusion of fluctuations or disturbances that might exist in the system under consideration which are not always quantifiable or may even be unknown. This curve is mainly used for modeling the length variable whereas a generalized version, including a new parameter b > or = 1, allows for modeling both length and weight for some animal species in both isometric (b = 3) and allometric (b not = 3) situations. In this paper a stochastic model related to the generalized von Bertalanffy growth curve is proposed. This model allows to investigate the time evolution of growth variables associated both with individual behaviors and mean population behavior. Also, with the purpose of fitting the above-mentioned model to real data and so be able to forecast and analyze particular characteristics, we study the maximum likelihood estimation of the parameters of the model. In addition, and regarding the numerical problems posed by solving the likelihood equations, a strategy is developed for obtaining initial solutions for the usual numerical procedures. Such strategy is validated by means of simulated examples. Finally, an application to real data of mean weight of swordfish is presented.

  5. Direct Growth and Controlled Coalescence of Thick AlN Template on Micro-circle Patterned Si Substrate

    PubMed Central

    Tran, Binh Tinh; Hirayama, Hideki; Maeda, Noritoshi; Jo, Masafumi; Toyoda, Shiro; Kamata, Norihiko

    2015-01-01

    High-density micro-circle patterned Si substrates were successfully fabricated for the direct overgrowth of thick AlN templates by using NH3 pulsed-flow multilayer AlN growth and epitaxial lateral overgrowth techniques. The experimental results show that an 8-μm-thick AlN template was grown at a very high growth rate on the substrates. The AlN template had full widths at half maximum of 0.23° and 0.37° for the (002) and (102) reflection planes in X-ray diffraction rocking curves. Atomic force microscopy and transmission electron microscopy confirmed that the roughness of the surface was low (3.5 nm) and the dislocation density was very low (1.5 × 108 cm−2 (screw), 3.7 × 108 (edge) cm−2). PMID:26439169

  6. A cortical folding model incorporating stress-dependent growth explains gyral wavelengths and stress patterns in the developing brain

    NASA Astrophysics Data System (ADS)

    Bayly, P. V.; Okamoto, R. J.; Xu, G.; Shi, Y.; Taber, L. A.

    2013-02-01

    In humans and many other mammals, the cortex (the outer layer of the brain) folds during development. The mechanics of folding are not well understood; leading explanations are either incomplete or at odds with physical measurements. We propose a mathematical model in which (i) folding is driven by tangential expansion of the cortex and (ii) deeper layers grow in response to the resulting stress. In this model the wavelength of cortical folds depends predictably on the rate of cortical growth relative to the rate of stress-induced growth. We show analytically and in simulations that faster cortical expansion leads to shorter gyral wavelengths; slower cortical expansion leads to long wavelengths or even smooth (lissencephalic) surfaces. No inner or outer (skull) constraint is needed to produce folding, but initial shape and mechanical heterogeneity influence the final shape. The proposed model predicts patterns of stress in the tissue that are consistent with experimental observations.

  7. Sensitivity and Predictive Value of 15 PubMed Search Strategies to Answer Clinical Questions Rated Against Full Systematic Reviews

    PubMed Central

    Merglen, Arnaud; Courvoisier, Delphine S; Combescure, Christophe; Garin, Nicolas; Perrier, Arnaud; Perneger, Thomas V

    2012-01-01

    Background Clinicians perform searches in PubMed daily, but retrieving relevant studies is challenging due to the rapid expansion of medical knowledge. Little is known about the performance of search strategies when they are applied to answer specific clinical questions. Objective To compare the performance of 15 PubMed search strategies in retrieving relevant clinical trials on therapeutic interventions. Methods We used Cochrane systematic reviews to identify relevant trials for 30 clinical questions. Search terms were extracted from the abstract using a predefined procedure based on the population, interventions, comparison, outcomes (PICO) framework and combined into queries. We tested 15 search strategies that varied in their query (PIC or PICO), use of PubMed’s Clinical Queries therapeutic filters (broad or narrow), search limits, and PubMed links to related articles. We assessed sensitivity (recall) and positive predictive value (precision) of each strategy on the first 2 PubMed pages (40 articles) and on the complete search output. Results The performance of the search strategies varied widely according to the clinical question. Unfiltered searches and those using the broad filter of Clinical Queries produced large outputs and retrieved few relevant articles within the first 2 pages, resulting in a median sensitivity of only 10%–25%. In contrast, all searches using the narrow filter performed significantly better, with a median sensitivity of about 50% (all P < .001 compared with unfiltered queries) and positive predictive values of 20%–30% (P < .001 compared with unfiltered queries). This benefit was consistent for most clinical questions. Searches based on related articles retrieved about a third of the relevant studies. Conclusions The Clinical Queries narrow filter, along with well-formulated queries based on the PICO framework, provided the greatest aid in retrieving relevant clinical trials within the 2 first PubMed pages. These results can help

  8. Longitudinal burnout-collaboration patterns in Japanese medical care workers at special needs schools: a latent class growth analysis.

    PubMed

    Kanayama, Mieko; Suzuki, Machiko; Yuma, Yoshikazu

    2016-01-01

    The present study aimed to identify and characterize potential burnout types and the relationship between burnout and collaboration over time. Latent class growth analysis and the growth mixture model were used to identify and characterize heterogeneous patterns of longitudinal stability and change in burnout, and the relationship between burnout and collaboration. We collected longitudinal data at three time points based on Japanese academic terms. The 396 study participants included academic teachers, yogo teachers, and registered nurses in Japanese special needs schools. The best model included four types of both burnout and collaboration in latent class growth analysis with intercept, slope, and quadratic terms. The four types of burnout were as follows: low stable, moderate unstable, high unstable, and high decreasing. They were identified as involving inverse collaboration function. The results indicated that there could be dynamic burnout types, namely moderate unstable, high unstable, and high decreasing, when focusing on growth trajectories in latent class analyses. The finding that collaboration was dynamic for dynamic burnout types and stable for stable burnout types is of great interest. This was probably related to the inverse relationship between the two constructs. PMID:27366107

  9. Longitudinal burnout-collaboration patterns in Japanese medical care workers at special needs schools: a latent class growth analysis.

    PubMed

    Kanayama, Mieko; Suzuki, Machiko; Yuma, Yoshikazu

    2016-01-01

    The present study aimed to identify and characterize potential burnout types and the relationship between burnout and collaboration over time. Latent class growth analysis and the growth mixture model were used to identify and characterize heterogeneous patterns of longitudinal stability and change in burnout, and the relationship between burnout and collaboration. We collected longitudinal data at three time points based on Japanese academic terms. The 396 study participants included academic teachers, yogo teachers, and registered nurses in Japanese special needs schools. The best model included four types of both burnout and collaboration in latent class growth analysis with intercept, slope, and quadratic terms. The four types of burnout were as follows: low stable, moderate unstable, high unstable, and high decreasing. They were identified as involving inverse collaboration function. The results indicated that there could be dynamic burnout types, namely moderate unstable, high unstable, and high decreasing, when focusing on growth trajectories in latent class analyses. The finding that collaboration was dynamic for dynamic burnout types and stable for stable burnout types is of great interest. This was probably related to the inverse relationship between the two constructs.

  10. Identification of SHRUBBY, a SHORT-ROOT and SCARECROW interacting protein that controls root growth and radial patterning.

    PubMed

    Koizumi, Koji; Gallagher, Kimberly L

    2013-03-01

    The timing and extent of cell division is particularly important for the growth and development of multicellular organisms. Roots of the model organism Arabidopsis thaliana have been widely studied as a paradigm for organ development in plants. In the Arabidopsis root, the plant-specific GRAS family transcription factors SHORT-ROOT (SHR) and SCARECROW (SCR) are key regulators of root growth and of the asymmetric cell divisions that separate the ground tissue into two separate layers: the endodermis and cortex. To elucidate the role of SHR in root development, we identified 17 SHR-interacting proteins. Among those isolated was At5g24740, which we named SHRUBBY (SHBY). SHBY is a vacuolar sorting protein with similarity to the gene responsible for Cohen syndrome in humans. Hypomorphic alleles of shby caused poor root growth, decreased meristematic activity and defects in radial patterning that are characterized by an increase in the number of cell divisions in the ground tissue that lead to extra cells in the cortex and endodermis, as well as additional cell layers. Analysis of genetic and molecular markers indicates that SHBY acts in a pathway that partially overlaps with SHR, SCR, PLETHORA1 and PLETHORA2 (PLT1 and PLT2). The shby-1 root phenotype was partially phenocopied by treatment of wild-type roots with the proteosome inhibitor MG132 or the gibberellic acid (GA) synthesis inhibitor paclobutrazol (PAC). Our results indicate that SHBY controls root growth downstream of GA in part through the regulation of SHR and SCR.

  11. Growth pattern switch of renal cells and expression of cell cycle related proteins at the early stage of diabetic nephropathy

    SciTech Connect

    Zhang Yanling; Shi Yonghong; Liu Yaling; Dong Hui; Liu, Maodong; Li Ying; Duan Huijun

    2007-11-09

    Renal hypertrophy, partly due to cell proliferation and hypertrophy, has been found correlated to renal function deterioration in diabetes mellitus. We screened the up-regulated cell cycle related genes to investigate cell growth and the expression of cell cycle regulating proteins at the early stage of diabetic nephropathy using STZ-induced diabetic rats. Cyclin E, CDK{sub 2} and P{sup 27} were found significantly up-regulated in diabetic kidney. Increased cell proliferation in the kidney was seen at day 3, peaked at day 5, and returned to normal level at day 30. Cyclin E and CDK{sub 2} expression also peeked at day 5 and P{sup 27} activity peaked at day 14. These findings indicate that a hyperplastic growth period of renal cells is followed by a hypertrophic growth period at the early stage of diabetes. The growth pattern switch may be regulated by cell cycle regulating proteins, Cyclin E, CDK{sub 2}, and P{sup 27}.

  12. Longitudinal burnout-collaboration patterns in Japanese medical care workers at special needs schools: a latent class growth analysis

    PubMed Central

    Kanayama, Mieko; Suzuki, Machiko; Yuma, Yoshikazu

    2016-01-01

    The present study aimed to identify and characterize potential burnout types and the relationship between burnout and collaboration over time. Latent class growth analysis and the growth mixture model were used to identify and characterize heterogeneous patterns of longitudinal stability and change in burnout, and the relationship between burnout and collaboration. We collected longitudinal data at three time points based on Japanese academic terms. The 396 study participants included academic teachers, yogo teachers, and registered nurses in Japanese special needs schools. The best model included four types of both burnout and collaboration in latent class growth analysis with intercept, slope, and quadratic terms. The four types of burnout were as follows: low stable, moderate unstable, high unstable, and high decreasing. They were identified as involving inverse collaboration function. The results indicated that there could be dynamic burnout types, namely moderate unstable, high unstable, and high decreasing, when focusing on growth trajectories in latent class analyses. The finding that collaboration was dynamic for dynamic burnout types and stable for stable burnout types is of great interest. This was probably related to the inverse relationship between the two constructs. PMID:27366107

  13. Impact of growth patterns and early diet on obesity and cardiovascular risk factors in young children from developing countries.

    PubMed

    Corvalán, Camila; Kain, Juliana; Weisstaub, Gerardo; Uauy, Ricardo

    2009-08-01

    Non-communicable chronic diseases are now a worldwide epidemic. Diet and physical activity throughout life are among its main determinants. In countries undergoing the early stages of the nutrition transition weight gain from birth to 2 years of life is related to lean mass gain, while ponderal gain after age 2 years is related to adiposity and later diabetes and CVD risk. Evidence from developing countries undergoing the more advanced stages of the nutrition transition is limited. The early growth patterns of a cohort of Chilean children born in 2002 with normal birth weight who at 4 years had a high prevalence of obesity and CVD risk factors have been assessed. Results indicate that BMI gain in early life, particularly from 6 months to 24 months, is positively associated with adiposity and CVD risk status at 4 years. These results together with existing evidence suggest that actions to prevent obesity and nutrition-related chronic diseases in developing countries should start early in life, possibly after 6 months of age. This approach should consider assessing the effect of mode of feeding and the amount and type of energy fed, as well as the resulting growth patterns. The challenge for researchers addressing the nutrition transition is to define the optimal nutrition in early life, considering not only the short- and long-term health consequences but also taking into account the stage of the nutritional transition for the given population of interest. The latter will probably require redefining optimal postnatal growth based on the context of maternal size and fetal growth. PMID:19400973

  14. Development-related expression patterns of protein-coding and miRNA genes involved in porcine muscle growth.

    PubMed

    Wang, F J; Jin, L; Guo, Y Q; Liu, R; He, M N; Li, M Z; Li, X W

    2014-01-01

    Muscle growth and development is associated with remarkable changes in protein-coding and microRNA (miRNA) gene expression. To determine the expression patterns of genes and miRNAs related to muscle growth and development, we measured the expression levels of 25 protein-coding and 16 miRNA genes in skeletal and cardiac muscles throughout 5 developmental stages by quantitative reverse transcription-polymerase chain reaction. The Short Time-Series Expression Miner (STEM) software clustering results showed that growth-related genes were downregulated at all developmental stages in both the psoas major and longissimus dorsi muscles, indicating their involvement in early developmental stages. Furthermore, genes related to muscle atrophy, such as forkhead box 1 and muscle ring finger, showed unregulated expression with increasing age, suggesting a decrease in protein synthesis during the later stages of skeletal muscle development. We found that development of the cardiac muscle was a complex process in which growth-related genes were highly expressed during embryonic development, but they did not show uniform postnatal expression patterns. Moreover, the expression level of miR-499, which enhances the expression of the β-myosin heavy chain, was significantly different in the psoas major and longissimus dorsi muscles, suggesting the involvement of miR-499 in the determination of skeletal muscle fiber types. We also performed correlation analyses of messenger RNA and miRNA expression. We found negative relationships between miR-486 and forkhead box 1, and miR-133a and serum response factor at all developmental stages, suggesting that forkhead box 1 and serum response factor are potential targets of miR-486 and miR-133a, respectively.

  15. Simultaneous growth of self-patterned carbon nanotube forests with dual height scales

    NASA Astrophysics Data System (ADS)

    Sam, Ebru Devrim; Kucukayan-Dogu, Gokce; Baykal, Beril; Dalkilic, Zeynep; Rana, Kuldeep; Bengu, Erman

    2012-05-01

    In this study, we report on a unique, one-step fabrication technique enabling the simultaneous synthesis of vertically aligned multi-walled carbon nanotubes (VA-MWCNTs) with dual height scales through alcohol catalyzed chemical vapor deposition (ACCVD). Regions of VA-MWCNTs with different heights were well separated from each other leading to a self-patterning on the surface. We devised a unique layer-by-layer process for application of catalyst and inhibitor precursors on oxidized Si (100) surfaces before the ACCVD step to achieve a hierarchical arrangement. Patterning could be controlled by adjusting the molarity and application sequence of precursors. Contact angle measurements on these self-patterned surfaces indicated that manipulation of these hierarchical arrays resulted in a wide range of hydrophobic behavior changing from that of a sticky rose petal to a lotus leaf.In this study, we report on a unique, one-step fabrication technique enabling the simultaneous synthesis of vertically aligned multi-walled carbon nanotubes (VA-MWCNTs) with dual height scales through alcohol catalyzed chemical vapor deposition (ACCVD). Regions of VA-MWCNTs with different heights were well separated from each other leading to a self-patterning on the surface. We devised a unique layer-by-layer process for application of catalyst and inhibitor precursors on oxidized Si (100) surfaces before the ACCVD step to achieve a hierarchical arrangement. Patterning could be controlled by adjusting the molarity and application sequence of precursors. Contact angle measurements on these self-patterned surfaces indicated that manipulation of these hierarchical arrays resulted in a wide range of hydrophobic behavior changing from that of a sticky rose petal to a lotus leaf. Electronic supplementary information (ESI) available: Fig. S1; AFM image of the Co-O layer which was first dried at 40 °C and then oxidized at 200 °C. Fig. S2; graph relative to the area of CNT islands for different

  16. Pattern Formation in Keller-Segel Chemotaxis Models with Logistic Growth

    NASA Astrophysics Data System (ADS)

    Jin, Ling; Wang, Qi; Zhang, Zengyan

    In this paper, we investigate pattern formation in Keller-Segel chemotaxis models over a multidimensional bounded domain subject to homogeneous Neumann boundary conditions. It is shown that the positive homogeneous steady state loses its stability as chemoattraction rate χ increases. Then using Crandall-Rabinowitz local theory with χ being the bifurcation parameter, we obtain the existence of nonhomogeneous steady states of the system which bifurcate from this homogeneous steady state. Stability of the bifurcating solutions is also established through rigorous and detailed calculations. Our results provide a selection mechanism of stable wavemode which states that the only stable bifurcation branch must have a wavemode number that minimizes the bifurcation value. Finally, we perform extensive numerical simulations on the formation of stable steady states with striking structures such as boundary spikes, interior spikes, stripes, etc. These nontrivial patterns can model cellular aggregation that develop through chemotactic movements in biological systems.

  17. Oligogalacturonides: plant damage-associated molecular patterns and regulators of growth and development.

    PubMed

    Ferrari, Simone; Savatin, Daniel V; Sicilia, Francesca; Gramegna, Giovanna; Cervone, Felice; Lorenzo, Giulia De

    2013-01-01

    Oligogalacturonides (OGs) are oligomers of alpha-1,4-linked galacturonosyl residues released from plant cell walls upon partial degradation of homogalacturonan. OGs are able to elicit defense responses, including accumulation of reactive oxygen species and pathogenesis-related proteins, and protect plants against pathogen infections. Recent studies demonstrated that OGs are perceived by wall-associated kinases and share signaling components with microbe-associated molecular patterns. For this reason OGs are now considered true damage-associated molecular patterns that activate the plant innate immunity and may also be involved in the activation of responses to mechanical wounding. Furthermore, OGs appear to modulate developmental processes, likely through their ability to antagonize auxin responses. Here we review our current knowledge on the role and mode of action of this class of oligosaccharides in plant defense and development.

  18. Influence of condition of growth of bacterial colonies on fractal dimension of bacterial speckle patterns

    NASA Astrophysics Data System (ADS)

    Ulyanov, Alexander S.; Lyapina, Anna M.; Ulianova, Onega V.; Feodorova, Valentina A.

    2011-03-01

    New field of application of fractal dimensions is proposed. A technique, based on the calculation of fractal dimension, was used for express-diagnostics and identification of bacteria of the vaccine strain Yersinia pestis EV line NIIEG. Purpose of this study was the experimental investigation of properties of speckle patterns, formed under laser illumination of a single colony of the strain that was grown on different agars.

  19. Influence of condition of growth of bacterial colonies on fractal dimension of bacterial speckle patterns

    NASA Astrophysics Data System (ADS)

    Ulyanov, Alexander S.; Lyapina, Anna M.; Ulianova, Onega V.; Feodorova, Valentina A.

    2010-10-01

    New field of application of fractal dimensions is proposed. A technique, based on the calculation of fractal dimension, was used for express-diagnostics and identification of bacteria of the vaccine strain Yersinia pestis EV line NIIEG. Purpose of this study was the experimental investigation of properties of speckle patterns, formed under laser illumination of a single colony of the strain that was grown on different agars.

  20. Structure and Growth Pattern of Pseudoteeth in Pelagornis mauretanicus (Aves, Odontopterygiformes, Pelagornithidae)

    PubMed Central

    Louchart, Antoine; Sire, Jean-Yves; Mourer-Chauviré, Cécile; Geraads, Denis; Viriot, Laurent; de Buffrénil, Vivian

    2013-01-01

    The extinct Odontopterygiformes are the sole birds known to possess strong and sharp bony pseudoteeth, the shape and location of which are closely mimetic of real teeth. The structure of the pseudoteeth is investigated here in a late Pliocene/early Pleistocene species, Pelagornis mauretanicus, using X-ray microtomography and thin sections. The results are interpreted with regard to the pseudotooth mode of growth, and have implications concerning aspects of Pelagornis ecology. The larger pseudoteeth are hollow and approximately cone-shaped, and the smaller ones are rostro-caudally constricted. The walls of pseudoteeth are composed of bone tissue of the fibro-lamellar type, which is intensively remodeled by Haversian substitution. The jaw bones display the same structure as the pseudoteeth, but their vascular canals are oriented parallel to the long axis of the bones, whereas they are perpendicular to this direction in the pseudoteeth. There is no hiatus or evidence of a fusion between the pseudoteeth and the jaw bones. Two possible models for pseudotooth growth are derived from the histological data. The most plausible model is that pseudotooth growth began after the completion of jaw bone growth, as a simple local protraction of periosteal osteogenic activity. Pseudotooth development thus occurred relatively late during ontogeny. The highly vascularized structure and the relative abundance of parallel-fibered bone tissue in the pseudoteeth suggest poor mechanical capabilities. The pseudoteeth were most likely covered and protected by the hardened, keratinized rhamphotheca in the adult during life. The late development of the pseudoteeth would involve a similarly late and/or partial hardening of the rhamphotheca, as displayed by extant Anseriformes, Apterygiformes and some Charadriiformes. This would add support to the hypothesis of a close phylogenetic relationship between Odontopterygiformes and Anseriformes. The late maturation of the Pelagornis feeding apparatus

  1. Ontogenic and spatial patterns in diet and growth of lake trout in Lake Michigan

    USGS Publications Warehouse

    Madenjian, Charles P.; DeSorcie, Timothy J.; Stedman, Ralph M.

    1998-01-01

    Lake trout Salvelinus namaycush in nearshore waters of Lake Michigan grow faster than lake trout residing offshore on Sheboygan Reef, which is in midlake. We examined the stomachs of lake trout, spanning ages 1 through 16, caught in both nearshore and offshore environments of Lake Michigan during 1994 and 1995 to determine whether diet differences may be responsible for the difference in growth rate. A comparison of the diets, coupled with bioenergetics modeling, indicated that juvenile lake trout on Sheboygan Reef experienced slow growth due to low food availability rather than to cold water temperatures. The availability of appropriate-size prey appeared to regulate lake trout growth. Small prey fish were probably not readily available to small (200- to 399-mm total length) lake trout on Sheboygan Reef, a substantial portion of whose diet consisted of invertebrates; in contrast, nearshore juveniles had a nearly 100% fish diet. Growth rate on the reef remained slow through intermediate lake trout sizes (400-599 mm total length), presumably due to low availability of rainbow smelt Osmerus mordax on the reef. Once lake trout achieved total lengths of approximately 600 mm, they grew slightly faster on Sheboygan Reef than near shore, indicating that large (>170-mm total length) prey fish were readily available to lake trout in the reef area. On a wet-weight basis, alewife Alosa pseudoharengus dominated the diet of large (a?Y 600 mm total length) lake trout from both the nearshore and offshore regions of the lake, although bloater Coregonus hoyi composed over 30% of the diet on Sheboygan Reef and in southeastern nearshore Lake Michigan. Size of alewife prey increased with lake trout size. The bloater population currently represents the bulk of the biomass of the adult prey fish community, so our diet analysis suggests that large lake trout are continuing to select alewives.

  2. Postnatal Growth Patterns in a Chilean Cohort: The Role of SES and Family Environment.

    PubMed

    Kang Sim, D E; Cappiello, M; Castillo, M; Lozoff, B; Martinez, S; Blanco, E; Gahagan, S

    2012-01-01

    Objective. This study examined how family environmental characteristics served as mediators in the relationship between socioeconomic conditions and infant growth in a cohort of Chilean infants. Methods. We studied 999 infants, born between 1991 and 1996, from a longitudinal cohort which began as an iron deficiency anemia preventive trial. SES (Graffar Index), the Life Experiences Survey, and the Home Observation for Measurement of the Environment (HOME) were assessed in infancy. Using path analysis, we assessed the relationships between the social factors, home environment, and infant growth. Results. During the first year, weight and length gain averaged 540 grams/month and 6.5 cm/month, respectively. In the path analysis model for weight gain, higher SES and a better physical environment were positively related to higher maternal warmth, which in turn was associated with higher average weight gain. Higher SES was directly related to higher average length gain. Conclusions. In our cohort, a direct relationship between SES and length gain developed during infancy. Higher SES was indirectly related to infant weight gain through the home environment and maternal warmth. As the fastest growing infants are at risk for later obesity, new strategies are needed to encourage optimal rather than maximal growth. PMID:22666275

  3. Seasonality determines patterns of growth and age structure over a geographic gradient in an ectothermic vertebrate.

    PubMed

    Hjernquist, Mårten B; Söderman, Fredrik; Jönsson, K Ingemar; Herczeg, Gábor; Laurila, Anssi; Merilä, Juha

    2012-11-01

    Environmental variation connected with seasonality is likely to affect the evolution of life-history strategies in ectotherms, but there is no consensus as to how important life-history traits like body size are influenced by environmental variation along seasonal gradients. We compared adult body size, skeletal growth, mean age, age at first reproduction and longevity among 11 common frog (Rana temporaria) populations sampled along a 1,600-km-long latitudinal gradient across Scandinavia. Mean age, age at first reproduction and longevity increased linearly with decreasing growth season length. Lifetime activity (i.e. the estimated number of active days during life-time) was highest at mid-latitudes and females had on average more active days throughout their lives than males. Variation in body size was due to differences in lifetime activity among populations--individuals (especially females) were largest where they had the longest cumulative activity period--as well as to differences between populations in skeletal growth rate as determined by skeletochronological analyses. Especially, males grew faster at intermediate latitudes. While life-history trait variation was strongly associated with latitude, the direction and shape of these relationships were sex- and trait-specific. These context-dependent relationships may be the result of life-history trade-offs enforced by differences in future reproductive opportunities and time constraints among the populations. Thus, seasonality appears to be an important environmental factor shaping life-history trait variation in common frogs. PMID:22565493

  4. Postnatal Growth Patterns in a Chilean Cohort: The Role of SES and Family Environment.

    PubMed

    Kang Sim, D E; Cappiello, M; Castillo, M; Lozoff, B; Martinez, S; Blanco, E; Gahagan, S

    2012-01-01

    Objective. This study examined how family environmental characteristics served as mediators in the relationship between socioeconomic conditions and infant growth in a cohort of Chilean infants. Methods. We studied 999 infants, born between 1991 and 1996, from a longitudinal cohort which began as an iron deficiency anemia preventive trial. SES (Graffar Index), the Life Experiences Survey, and the Home Observation for Measurement of the Environment (HOME) were assessed in infancy. Using path analysis, we assessed the relationships between the social factors, home environment, and infant growth. Results. During the first year, weight and length gain averaged 540 grams/month and 6.5 cm/month, respectively. In the path analysis model for weight gain, higher SES and a better physical environment were positively related to higher maternal warmth, which in turn was associated with higher average weight gain. Higher SES was directly related to higher average length gain. Conclusions. In our cohort, a direct relationship between SES and length gain developed during infancy. Higher SES was indirectly related to infant weight gain through the home environment and maternal warmth. As the fastest growing infants are at risk for later obesity, new strategies are needed to encourage optimal rather than maximal growth.

  5. [Effects of different patterns surface mulching on soil properties and fruit trees growth and yield in an apple orchard].

    PubMed

    Zhang, Yi; Xie, Yong-Sheng; Hao, Ming-De; She, Xiao-Yan

    2010-02-01

    Taking a nine-year-old Fuji apple orchard in Loess Plateau as test object, this paper studied the effects of different patterns surface mulching (clean tillage, grass cover, plastic film mulch, straw mulch, and gravel mulch) on the soil properties and fruit trees growth and yield in this orchard. Grass cover induced the lowest differentiation of soil moisture profile, while gravel mulch induced the highest one. In treatment gravel mulch, the soil moisture content in apple trees root zone was the highest, which meant that there was more water available to apple trees. Surface mulching had significant effects on soil temperature, and generally resulted in a decrease in the maximum soil temperature. The exception was treatment plastic film mulch, in which, the soil temperature in summer exceeded the maximum allowable temperature for continuous root growth and physiological function. With the exception of treatment plastic film mulch, surface mulching increased the soil CO2 flux, which was the highest in treatment grass cover. Surface mulching also affected the proportion of various branch types and fruit yield. The proportion of medium-sized branches and fruit yield were the highest in treatment gravel mulch, while the fruit yield was the lowest in treatment grass cover. Factor analysis indicated that among the test surface mulching patterns, gravel mulch was most suitable for the apple orchards in gully region of Loess Plateau.

  6. Precisely Patterned Growth of Ultra-Long Single-Crystalline Organic Microwire Arrays for Near-Infrared Photodetectors.

    PubMed

    Wang, Hui; Deng, Wei; Huang, Liming; Zhang, Xiujuan; Jie, Jiansheng

    2016-03-01

    Owing to extraordinary properties, small-molecule organic micro/nanocrystals are identified to be prospective system to construct new-generation organic electronic and optoelectronic devices. Alignment and patterning of organic micro/nanocrystals at desired locations are prerequisite for their device applications in practice. Though various methods have been developed to control their directional growth and alignment, high-throughput precise positioning and patterning of the organic micro/nanocrystals at desired locations remains a challenge. Here, we report a photoresist-assisted evaporation method for large-area growth of precisely positioned ultralong methyl-squarylium (MeSq) microwire (MW) arrays. Positions as well as alignment densities of the MWs can be precisely controlled with the aid of the photoresist-template that fabricated by photolithography process. This strategy enables large-scale fabrication of organic MW arrays with nearly the same accuracy, uniformity, and reliability as photolithography. Near-infrared (NIR) photodetectors based on the MeSq MW arrays show excellent photoresponse behavior and are capable of detecting 808 nm light with high stability and reproducibility. The high on/off ratio of 1600 is significantly better than other organic nanostructure-based optical switchers. More importantly, this strategy can be readily extended to other organic molecules, revealing the great potential of photoresist-assisted evaporation method for future high-performance organic optoelectronic devices.

  7. Direct growth of patterned graphene on SiC(0001) surfaces by KrF excimer-laser irradiation

    NASA Astrophysics Data System (ADS)

    Hattori, Masakazu; Furukawa, Kazuaki; Takamura, Makoto; Hibino, Hiroki; Ikenoue, Hiroshi

    2015-03-01

    A novel method of direct growth of patterned graphene on SiC(0001) surfaces using KrF excimer-laser irradiation is proposed. It relies on the local sublimation of Si atoms within the irradiated area to induce graphene growth through a rearrangement of surplus carbon. A laser with a wavelength of 248 nm was pulsed with a duration of 55 ns and a repetition rate of 100 Hz that was used to graphene forming. Following laser irradiation of 1.2 J/cm2 (5000 shots) under an Ar atmosphere (500 Pa), characteristic graphene peaks were observed in the Raman spectra of the irradiated area, thereby confirming the formation of graphene. The ratio between the graphene bands in the Raman spectra was used to estimate the grain size at 61.3 nm. Through high-resolution transmission electron microscopy, it was confirmed that two layers of graphene were indeed formed in the laser irradiated region. Using this knowledge, we also demonstrate that line-and-space (LandS) graphene patterns with a pitch of 8 μm can be directly formed using our method.

  8. Gibberellin 3-oxidase gene expression patterns influence gibberellin biosynthesis, growth, and development in pea.

    PubMed

    Reinecke, Dennis M; Wickramarathna, Aruna D; Ozga, Jocelyn A; Kurepin, Leonid V; Jin, Alena L; Good, Allen G; Pharis, Richard P

    2013-10-01

    Gibberellins (GAs) are key modulators of plant growth and development. PsGA3ox1 (LE) encodes a GA 3β-hydroxylase that catalyzes the conversion of GA20 to biologically active GA1. To further clarify the role of GA3ox expression during pea (Pisum sativum) plant growth and development, we generated transgenic pea lines (in a lele background) with cauliflower mosaic virus-35S-driven expression of PsGA3ox1 (LE). PsGA3ox1 transgene expression led to higher GA1 concentrations in a tissue-specific and development-specific manner, altering GA biosynthesis and catabolism gene expression and plant phenotype. PsGA3ox1 transgenic plants had longer internodes, tendrils, and fruits, larger stipules, and displayed delayed flowering, increased apical meristem life, and altered vascular development relative to the null controls. Transgenic PsGA3ox1 overexpression lines were then compared with lines where endogenous PsGA3ox1 (LE) was introduced, by a series of backcrosses, into the same genetic background (BC LEle). Most notably, the BC LEle plants had substantially longer internodes containing much greater GA1 levels than the transgenic PsGA3ox1 plants. Induction of expression of the GA deactivation gene PsGA2ox1 appears to make an important contribution to limiting the increase of internode GA1 to modest levels for the transgenic lines. In contrast, PsGA3ox1 (LE) expression driven by its endogenous promoter was coordinated within the internode tissue to avoid feed-forward regulation of PsGA2ox1, resulting in much greater GA1 accumulation. These studies further our fundamental understanding of the regulation of GA biosynthesis and catabolism at the tissue and organ level and demonstrate that the timing/localization of GA3ox expression within an organ affects both GA homeostasis and GA1 levels, and thereby growth.

  9. Cultural variation in early feeding pattern and maternal perceptions of infant growth.

    PubMed

    van Eijsden, Manon; Meijers, Claire M C; Jansen, Jessica E; de Kroon, Marlou L A; Vrijkotte, Tanja G M

    2015-08-14

    The perception of healthy growth and weight may differ between cultures, which could influence feeding practises and consequently affect the development of overweight. The present study examined ethnic variation in maternal perceptions of growth and their influence on feeding practises among Turkish and Dutch infants aged 0-6 months. Data were obtained from the mothers of 143 Turkish and 143 Dutch healthy, singleton, term infants with birth weights appropriate for gestational age, using structured interviews at 1, 4 and 6 months after birth. Compared with Dutch mothers, mothers of Turkish descent perceived a chubby infant more often as pretty (43 v. 22%), and were more often worried about their infant's growth (13 v. 4%). Turkish mothers were more likely to give full breast-feeding (BF) until at least 6 months (adjusted OR (aOR) 2.1, 95% CI 1.0, 4.3) and to start introducing complementary feeding, including rice flour porridge, at the age of 6 months (aOR 2.4, 95% CI 1.1, 4.9). Infants of Turkish descent were fed on average one milk feeding more during the day and, if introduced to complementary foods before 6 months, were more often given uncommon types of foods (e.g., yogurt and cookies) (aOR 2.1, 95% CI 1.1, 4.3). The differences in perceptions affected differences in feeding practises only to a small extent. Preventive advice offered to Turkish mothers in Child Health Care should include discussing choices of complementary foods and frequency of feeding from an early age onwards. In Dutch mothers, support for the continuation of BF remains an important issue.

  10. Peptide T bolus normalizes the growth hormone secretion pattern in two children with AIDS.

    PubMed

    Barbey-Morel, Charlotte; McDonnell, Kevin; Pert, Candace B; Adams, MerriBeth; Farrand, Dean; Ruff, Michael R; Lumpkin, Michael D

    2002-12-01

    In humans, HIV infection reduces growth hormone (GH) secretion contributing to AIDS wasting. In rats, the HIV envelope protein gp120 alone blocks GH secretion both in vitro and in vivo through GH-releasing hormone receptors. Peptide T, a modified octapeptide derived from gp120, normalizes GH secretion. We now report that an intravenous bolus of peptide T normalizes nocturnal GH secretion in two out of three children with AIDS. These results, coupled with the lack of toxicity of this experimental AIDS therapeutic, justify clinical trials for AIDS wasting and pediatric AIDS. A clinical and basic science update on peptide T appears in Current HIV Research. PMID:12535709

  11. Growth of solid and hollow gold particles through the thermal annealing of nanoscale patterned thin films

    SciTech Connect

    Lin, Junhao; He, Weidong; Vilayur Ganapathy, Subramanian; Peppernick, Samuel J.; Wang, Bin; Palepu, Sandeep; Remec, Miroslav; Hess, Wayne P.; Hmelo, Anthony B.; Pantelides, Sokrates T.; Dickerson, James

    2013-11-27

    Through thermally annealing well-arrayed, circular, nanoscale thin films of gold, deposited onto [111] silicon/silicon dioxide substrates, both solid and hollow gold particles of different morphologies with controllable sizes were obtained. The thin film could form individual particle or clusters of particles by tuning the diameter of it. Hollow gold particles were featured by their large size whose diameter was larger than 500 nm and confirmed by a cross-section view. Hollow gold particles show greater plasmonic field enhancement under photoemission electron microscopy. Potential growth mechanisms for these structures are explored

  12. Pathogen Associated Molecular Pattern (PAMP)-Triggered Immunity Is Compromised under C-Limited Growth

    PubMed Central

    Park, Hyeong Cheol; Lee, Shinyoung; Park, Bokyung; Choi, Wonkyun; Kim, Chanmin; Lee, Sanghun; Chung, Woo Sik; Lee, Sang Yeol; Sabir, Jamal; Bressan, Ray A.; Bohnert, Hans J.; Mengiste, Tesfaye; Yun, Dae-Jin

    2015-01-01

    In the interaction between plants and pathogens, carbon (C) resources provide energy and C skeletons to maintain, among many functions, the plant immune system. However, variations in C availability on pathogen associated molecular pattern (PAMP) triggered immunity (PTI) have not been systematically examined. Here, three types of starch mutants with enhanced susceptibility to Pseudomonas syringae pv. tomato DC3000 hrcC were examined for PTI. In a dark period-dependent manner, the mutants showed compromised induction of a PTI marker, and callose accumulation in response to the bacterial PAMP flagellin, flg22. In combination with weakened PTI responses in wild type by inhibition of the TCA cycle, the experiments determined the necessity of C-derived energy in establishing PTI. Global gene expression analyses identified flg22 responsive genes displaying C supply-dependent patterns. Nutrient recycling-related genes were regulated similarly by C-limitation and flg22, indicating re-arrangements of expression programs to redirect resources that establish or strengthen PTI. Ethylene and NAC transcription factors appear to play roles in these processes. Under C-limitation, PTI appears compromised based on suppression of genes required for continued biosynthetic capacity and defenses through flg22. Our results provide a foundation for the intuitive perception of the interplay between plant nutrition status and pathogen defense. PMID:25387755

  13. Morphological transition between diffusion-limited and ballistic aggregation growth patterns.

    PubMed

    Ferreira, S C; Alves, S G; Brito, A Faissal; Moreira, J G

    2005-05-01

    In this work, the transition between diffusion-limited (DLA) and ballistic aggregation (BA) models was reconsidered using a model in which biased random walks simulate the particle trajectories. The bias is controlled by a parameter lambda, which assumes the value lambda=0 (1) for the ballistic (diffusion-limited) aggregation model. Patterns growing from a single seed were considered. In order to simulate large clusters, an efficient algorithm was developed. For lambda (not equal to) 0 , the patterns are fractal on small length scales, but homogeneous on large ones. We evaluated the mean density of particles (-)rho in the region defined by a circle of radius r centered at the initial seed. As a function of r, (-)rho reaches the asymptotic value rho(0)(lambda) following a power law (-)rho = rho(0) +Ar(-gamma) with a universal exponent gamma=0.46 (2) , independent of lambda . The asymptotic value has the behavior rho(0) approximately |1-lambda|(beta) , where beta=0.26 (1) . The characteristic crossover length that determines the transition from DLA- to BA-like scaling regimes is given by xi approximately |1-lambda|(-nu) , where nu=0.61 (1) , while the cluster mass at the crossover follows a power law M(xi) approximately |1-lambda(-alpha) , where alpha=0.97 (2) . We deduce the scaling relations beta=nugamma and beta=2nu-alpha between these exponents. PMID:16089530

  14. Sequential growth of long DNA strands with user-defined patterns for nanostructures and scaffolds

    NASA Astrophysics Data System (ADS)

    Hamblin, Graham D.; Rahbani, Janane F.; Sleiman, Hanadi F.

    2015-05-01

    DNA strands of well-defined sequence are valuable in synthetic biology and nanostructure assembly. Drawing inspiration from solid-phase synthesis, here we describe a DNA assembly method that uses time, or order of addition, as a parameter to define structural complexity. DNA building blocks are sequentially added with in-situ ligation, then enzymatic enrichment and isolation. This yields a monodisperse, single-stranded long product (for example, 1,000 bases) with user-defined length and sequence pattern. The building blocks can be repeated with different order of addition, giving different DNA patterns. We organize DNA nanostructures and quantum dots using these backbones. Generally, only a small portion of a DNA structure needs to be addressable, while the rest is purely structural. Scaffolds with specifically placed unique sites in a repeating motif greatly minimize the number of components used, while maintaining addressability. This combination of symmetry and site-specific asymmetry within a DNA strand is easily accomplished with our method.

  15. [Spatial distribution pattern and allometric growth of three common species on moving sand dunes in Horqin Sandy Land, China].

    PubMed

    Jia, Mei-yu; Li, Xue-hua; Oh, Choong-hyeon; Park, Hong-chul; Miao, Chun-ping; Han, Xu

    2015-10-01

    Research on fine scale pattern and characteristics of allometric growth could contribute to better understanding plants' adaptation in moving sandy dunes. The abundance, height and biomass of 3 species Agriophilum aquarrosum, Corispermum candelabrum and Setaria viridis in twenty-eight 1 m x 1 m quadrats of Horqin Sandy Land were identified, mapped and described. The nearest neighbor method and O-ring O(r) function analysis were applied to analyze the spatial patterns. The results showed that the individual spatial pattern was mainly aggregated in 1 m x 1 m quadrat at community level but mainly random at population level. At 0-50 cm individual distance scale, both intraspecific and interspecific relationship were facilitation and aggregated distribution occurred at some scales and varied with increasing plant abundance in 1 m x 1 m quadrat. In 0-40 cm, the aggregated distribution of S. viridis and A. aquarrosum increased obviously; in 10-20 cm, both intraspecific and interspecific aggregation increased; in 10-30 cm, the occurrence possibility of positive correlations between S. viridis and A. aquarrosum, S. viridis and C. candelabrum all increased; in 40-50 cm, the possibility of positive correlations between A. squarrosum and S. viridis, A. squarrosum and C. candelabrum all increased. Research on the three species components indicated that the growth rate of above-ground was faster than that of underground. S. viridis had the highest ratio of under-ground biomass to above-ground biomass but its nutritional organs' biomass ratio was medium. C. candelabrum allocated more biomass to propagative organs and stem, but A. squarrosum allocated more biomass to nutritional organs. Based on the spatial distribution and allometric characteristics, the three common species in moving sand dunes preferred r strategy in their life history. PMID:26995902

  16. Effects of biological and methodological factors on volatile organic compound patterns during cultural growth of Mycobacterium avium ssp. paratuberculosis.

    PubMed

    Küntzel, Anne; Fischer, Sina; Bergmann, Andreas; Oertel, Peter; Steffens, Markus; Trefz, Phillip; Miekisch, Wolfram; Schubert, Jochen K; Reinhold, Petra; Köhler, Heike

    2016-01-01

    Mycobacterium avium ssp. paratuberculosis (MAP) causes chronic granulomatous enteritis in ruminants. Bacterial growth is still the diagnostic 'gold standard', but is very time consuming. MAP-specific volatile organic compounds (VOCs) above media could accelerate cultural diagnosis. The aim of this project was to assess the kinetics of a VOC profile linked to the growth of MAP in vitro. The following sources of variability were taken into account: five different culture media, three different MAP strains, inoculation with different bacterial counts, and different periods of incubation. Needle-trap microextraction was employed for pre-concentration of VOCs, and gas chromatography-mass spectrometry for subsequent analysis. All volatiles were identified and calibrated by analysing pure references at different concentration levels. More than 100 VOCs were measured in headspaces above MAP-inoculated and control slants. Results confirmed different VOC profiles above different culture media. Emissions could be assigned to either egg-containing media or synthetic ingredients. 43 VOCs were identified as potential biomarkers of MAP growth on Herrold's Egg Yolk Medium without significant differences between the tree MAP strains. Substances belonged to the classes of alcohols, aldehydes, esters, ketones, aliphatic and aromatic hydrocarbons. With increasing bacterial density the VOC concentrations above MAP expressed different patterns: the majority of substances increased (although a few decreased after reaching a peak), but nine VOCs clearly decreased. Data support the hypotheses that (i) bacteria emit different metabolites on different culture media; (ii) different MAP strains show uniform VOC patterns; and (iii) cultural diagnosis can be accelerated by taking specific VOC profiles into account. PMID:27604146

  17. Comparative cephalometric study of nasal cavity growth patterns in seven animal models.

    PubMed

    Losken, A; Mooney, M P; Siegel, M I

    1994-01-01

    Although primates have been the craniofacial growth models of choice, recent circumstances have stimulated the search for nonprimate models. In a series of studies we have described changes in various regions of the craniofacial complex for seven commonly used animal models. The present study examined the bony nasal cavity. One hundred and forty-four serial and cross-sectional lateral head x-rays were obtained for unoperated controls from previous growth studies. The sample consisted of data from 26 rats, 21 rabbits, 21 domestic cats, 23 domestic dogs, 17 baboons, 16 rhesus monkeys, and 20 chimpanzees. Comparative human data was taken from the Bolton Standards. The samples were divided into three age categories based on dental and somatic development. Midsagittal nasal cavity measurements included length, height, shape index, and area. Analysis was based on the percent increase in measures from the infant condition. Three major shapes were discerned at adulthood (1) vertical quadrangles (humans and cats); (2) triangles (chimpanzees, rhesus monkeys, and baboons), and (3) horizontal quadrangles (rabbits, rats, and dogs). Results showed that overall shape was best modeled by the chimpanzee and, as a nonprimate model, the laboratory cat. Rabbits and rats also showed similar percent changes for length or height dimensions at different ages, suggesting that these animals may be acceptable, inexpensive alternatives to primates in some experimental situations.

  18. Gender, season and habitat: Patterns of variation in photosynthetic activity, growth and fecundity in Thymelaea velutina

    NASA Astrophysics Data System (ADS)

    de la Bandera, Maria del Carmen; Traveset, Anna; Valladares, Fernando; Gulías, Javier

    2008-11-01

    Changes in the ecophysiological performance of a plant species due to different environmental conditions generally reflect adaptations to the habitat where the plant grows and are often related to its survival capacity in a particular place. We examined this with the dioecious shrub Thymelaea velutina, in two contrasting populations representing the extremes of the altitudinal gradient where the species lives (coastal dunes and mountain habitats over 1000 m). We measured net photosynthetic rates and stomatal conductance, estimated the level of plant stress by chlorophyll fluorescence, and assessed their correlations with growth rate, plant size, flower production and fruit set. We hypothesized that plants at high altitude were more photosynthetically stressed than at sea level and expected a gender × habitat interaction in performance as females need more resources than males. Plants in the mountain experienced chronic photoinhibition during winter and a reduced photosynthetic performance both in winter and spring compared to plants in coastal dunes. However, there was no association between any of the fluorescence variables and either plant growth or fecundity, suggesting that other factors are involved determining performance. Mountain plants showed also an apparent lower capacity of heat dissipation to excessive radiation than dune plants. In the dunes, the greater leaf area and mass can lead to a higher photosynthetic carbon gain by whole individuals compared to plants in the mountain. No effect of gender was detected on the ecophysiological performance of this species, which we partly attribute to the small size of fruits of the female plants.

  19. Growth patterns and shape development of zeolite nanocrystals in confined syntheses.

    PubMed

    Yoo, Won Cheol; Kumar, Sandeep; Penn, R Lee; Tsapatsis, Michael; Stein, Andreas

    2009-09-01

    The effects of confinement on the morphological development of the zeolite silicalite-1 were studied during hydrothermal synthesis in three-dimensionally ordered macroporous (3DOM) carbon monoliths. By scheduling multiple infiltration/hydrothermal reaction (IHT) steps using precursor solutions with high (H) or low nutrient content (L) in specific sequences, it was possible to obtain various zeolite morphologies of interest for technological applications. The special morphologies are also functions of shaping and templating effects by the 3DOM carbon reactor and functions of limited mass transport in the confined reaction environment. IHT steps employing high nutrient concentrations favor nucleation, whereas those using low nutrient concentrations provide growth-dominant conditions. Observed product morphologies include polycrystalline sphere arrays for the sequence HHH..., single crystal domains spanning dozens of macropores for the sequence LLL..., and faceted silicalite-1 crystallites with dimensions less than 100 nm with the sequence HLLL.... Most of these crystallites have dimensions less than 100 nm and would be suitable building blocks for seeded zeolite membrane growth. Finally, the sequence LLL...H introduces a secondary population of particles with smaller size, so that the size distribution of zeolite crystallites in the combined population may be tuned, for example, to optimize packing of particles. Hence, by choosing the appropriate infiltration program, it is possible to control grain sizes in polycrystalline particles (spheres and opaline arrays of spheres), which alters the concentration of grain boundaries in the particles and is expected to influence transport properties through the zeolite. PMID:19663496

  20. Arctica islandica - a unique paleoclimate archive (growth patterns, light stable isotopes, trace and minor elements)

    NASA Astrophysics Data System (ADS)

    Schone, B. R.; Holland, H. A.; Jochum, K. P.

    2012-12-01

    Shells of long-lived bivalve mollusks are becoming increasingly recognized as powerful paleoclimate archives. Since a decade or so, the ocean quahog, Arctica islandica, is the center of attention. This species inhabits large areas in the northern North Atlantic and can potentially provide the most detailed data ever on extratropical marine paleoclimate variability. Since shell growth is only interrupted for a few months in fall, the full seasonal amplitude of environmental variables is recorded in the shells, e.g. in the form of stable oxygen and carbon isotope values. Moreover, each shell portion can be placed in a precise temporal context by counting annual and, in fast-growing youth portions of the shells, daily increments. Age-detrended annual growth increment time-series of contemporaneous specimens from the same habitat exhibit a large degree of running similarity. Therefore, temporally overlapping time-series can be combined to form even longer chronologies spanning centuries to millennia and many generations of bivalves. Such composite chronologies have been used to reconstruct changes of quasi-decadal to multi-decadal climate variability during the late Holocene. Another heap of environmental information is locked in the shell chemistry, but often superimposed by vital effects. This presentation will provide a brief overview of important findings, present a new 1,040-yr long composite chronology from the North Sea based on 33 specimens and highlight some of the challenges involved with the trace and minor element chemistry of this species.

  1. Study of defect management in the growth of semipolar (11-22) GaN on patterned sapphire

    NASA Astrophysics Data System (ADS)

    Vennéguès, P.; Tendille, F.; De Mierry, P.

    2015-08-01

    This work describes, using mainly transmission electron microscopy as an investigation tool, the nature and behaviour of the crystalline defects which are present in (11-22) semipolar GaN films grown epitaxially on patterned r-sapphire substrates using a 3 step growth process. The microstructure at these different growth stages is described. The independent 3D-crystallites nucleated on the substrate surface contain threading dislocations resulting from the epitaxy on c-sapphire facets and basal stacking faults (BSFs), mainly in the  -c-wings. These defects are concentrated in a few hundred nanometre wide stripe-like regions emerging on the top facet of the islands. By a careful choice of the growth conditions, these defective regions may be overgrown by defect-free material, blocking their propagation towards the coalesced surface. However, when the 3D crystals coalesce, new dislocations together with very few BSFs are created at the coalescence boundaries. These coalescence defects propagate to the surface of the films in (0001) planes. In summary, the control of the nucleation and propagation of the crystalline defects allows obtaining large area semipolar films with very low defect densities: 7   ×   107 cm-2 for TDs and 70 cm-1 for BSFs.

  2. Growth Patterns in Pubertal HIV-infected Adolescents and their Correlation with Cytokines, IGF-1, IGFBP-1 and IGFBP-3

    PubMed Central

    Kessler, Marion; Kaul, Aditya; Santos-Malavé, Claritsa; Borkowsky, William; Kessler, Jason; Shah, Bina

    2014-01-01

    Objective To describe the final adult height (FAH) and pubertal growth patterns in HIV-infected adolescents and to compare this to an age matched population of seroreverting HIV-exposed uninfected (HEU) adolescents. Further, to evaluate the interplay of proinflammatory cytokines (PIC) with IGF-1, IGFBP-3 and IGFBP-1 during the pubertal growth spurt. Methods HIV-infected adolescents (n=34) and 12 HEU patients, who had achieved FAH were evaluated. Auxologic data, viral load, CD4 count and HAART were obtained via a retrospective chart review. Serum IL-1 α, IL-6, TNF-α, IGFBP-1, IGFBP-3 and IGF-1 were assessed. Results The mean FAH for the HIV-infected group was SDS -0.78 (+/−1.1) compared to 0.05 (+/−0.78) for the HEU (p = 0.034). There was a positive correlation between CD4 count and FAH (p=0.019). The mean age and magnitude of peak growth velocity (GV) was within normal limits. IL-1 α, IL-6, TNF α, IGFBP-3 and IGF-1 were not significantly correlated with HIV RNA or height. IGFBP-1 was detectable in 100% of poorly controlled HIV-infected patients and 25% of the HEU cohort (p = 0.0003). Conclusions The FAH of HIV-infected patients was significantly shorter than HEU and positively correlated with CD4 T-lymphocyte count. Our cohort demonstrated normal timing and magnitude of peak GV during puberty. PMID:23612635

  3. The oriented and patterned growth of fluorescent metal–organic frameworks onto functionalized surfaces

    PubMed Central

    Zhuang, Jinliang; Friedel, Jasmin

    2012-01-01

    Summary A metal–organic framework (MOF) material, [Zn2(adc)2(dabco)] (adc = anthracene-9,10-dicarboxylate, dabco = 1,4-diazabicyclo[2.2.2]­octane), the fluorescence of which depends on the loading of its nanopores, was synthesized in two forms: as free-flowing nanocrystals with different shapes and as surface-attached MOFs (SURMOFs). For the latter, we used self-assembled monolayers (SAMs) bearing functional groups, such as carboxylate and pyridyl groups, capable of coordinating to the constituents of the MOF. It could be demonstrated that this directed coordination also orients the nanocrystals deposited at the surface. Using two different patterning methods, i.e., microcontact printing and electron-beam lithography, the lateral distribution of the functional groups could be determined in such a way that the highly localized deposition of the SURMOF films became possible. PMID:23019553

  4. Analysis of directional root growth patterns from corn and soybean seeds germinated in space

    NASA Astrophysics Data System (ADS)

    Levine, H.; Tynes, G.; Norwood, K.

    The JOSE (JASON Outreach Seed Experiment) payload was the first plant experiment conducted on the International Space Station (ISS). It consisted of having an on-orbit watering of eight transparent seed pouches each of which contained 6 individual seeds of either soybean (Glycine max cv McCall) or corn ( Zea mays ). The seeds were glued to a germination paper substrate using a 1.2% guar glue solution. The payload was launched on the Orbiter Endeavour (STS-97; ISS Flight 4A) on 11/30/00 and transferred to the ISS on 12/8/00. The eight seed pouches were each watered with 12 mL of distilled water on 1/5/01. Two pouches containing corn plus two pouches containing soybean seeds were maintained in the light after watering. Two additional seed pouches of each species were maintained in the dark after watering. Digital photography was used to document the growth of the germinating seedlings in space. The images were down-linked to a world wide web site for dissemination to students. "Within" species differences (between the light and dark grown seedlings) as well as "between" species differences (comparing corn and soybean) were observed. By day 4 (post-imbibition) there was a clear phototropic effect in the light-grown corn seedlings, each, possessing a green shoot which grew upward towards the light source. In contrast, the dark-grown corn shoots were neither green (since chlorophyll synthesis had not been induced by light) nor were they growing in a uniform direction. For day 4 soybean seedlings, the only difference evident between those germinated under the light vs dark conditions was a slight greening up of the seeds maintained in the presence of light. For both the corn and soybean seedlings, roots grew in a random fashion, with some moving in an upward direction and others progressing downward, reflecting the lack of a gravitropic response which is the primary (earth-based) mechanism controlling the direction of root growth. By day 7 the initial 12 mL of water

  5. Divergent Transcriptional Regulatory Logic at the Intersection of Tissue Growth and Developmental Patterning

    PubMed Central

    Slattery, Matthew; Voutev, Roumen; Ma, Lijia; Nègre, Nicolas; White, Kevin P.; Mann, Richard S.

    2013-01-01

    The Yorkie/Yap transcriptional coactivator is a well-known regulator of cellular proliferation in both invertebrates and mammals. As a coactivator, Yorkie (Yki) lacks a DNA binding domain and must partner with sequence-specific DNA binding proteins in the nucleus to regulate gene expression; in Drosophila, the developmental regulators Scalloped (Sd) and Homothorax (Hth) are two such partners. To determine the range of target genes regulated by these three transcription factors, we performed genome-wide chromatin immunoprecipitation experiments for each factor in both the wing and eye-antenna imaginal discs. Strong, tissue-specific binding patterns are observed for Sd and Hth, while Yki binding is remarkably similar across both tissues. Binding events common to the eye and wing are also present for Sd and Hth; these are associated with genes regulating cell proliferation and “housekeeping” functions, and account for the majority of Yki binding. In contrast, tissue-specific binding events for Sd and Hth significantly overlap enhancers that are active in the given tissue, are enriched in Sd and Hth DNA binding sites, respectively, and are associated with genes that are consistent with each factor's previously established tissue-specific functions. Tissue-specific binding events are also significantly associated with Polycomb targeted chromatin domains. To provide mechanistic insights into tissue-specific regulation, we identify and characterize eye and wing enhancers of the Yki-targeted bantam microRNA gene and demonstrate that they are dependent on direct binding by Hth and Sd, respectively. Overall these results suggest that both Sd and Hth use distinct strategies – one shared between tissues and associated with Yki, the other tissue-specific, generally Yki-independent and associated with developmental patterning – to regulate distinct gene sets during development. PMID:24039600

  6. Contribution of Indian Psychiatrists to PubMed Listed Mental Health Literature During 1995–2013: an Exploratory Study

    PubMed Central

    Mohandoss, Anusa Arunachalam; Thavarajah, Rooban

    2016-01-01

    Introduction: Contribution of Indian Psychiatrists as publications in peer-reviewed journals listed with PubMed and their impact has not been studied. The aim of this manuscript is to assess such contribution using a new article level metric measure. The relative citation ratio (RCR) has been used to assess the quality, quantity, and impact of research output of Indian Psychiatrists. Materials and Methods: Publications by Indian psychiatrists in PubMed during 1995–2013 were collected, their RCR and associated factors estimated. The nationality of the journals, type of manuscripts, PubMed Central (PMC) visibility and the type of the journals were factored in. The data collected was analyzed. Descriptive statistics, Chi-square tests, correlations, and linear regression were performed. P ≤ 0.05 was taken as significant. Results: Using the criteria set, 1914 manuscripts were identified. Of the 1914 manuscripts, 1007 were cited at least once and among this, 40.7% were listed with PubMed while of the 907 non-PMC listed manuscripts, only 180 were never cited (P = 0.000). Of the 1032 manuscripts published in Indian journals, 474 were never cited while 214 of the manuscripts published with non-India based journals were never cited even once (P = 0.000). Discussion: The difference in terms of manuscripts visibility in PMC, nationality of journals and article type in analysis indicate that there exists an innate difference between the cited and noncited manuscripts. The probable explanation behind this and its associated phenomenon are discussed. PMID:27570340

  7. Using Clinical Data, Hypothesis Generation Tools and PubMed Trends to Discover the Association between Diabetic Retinopathy and Antihypertensive Drugs

    SciTech Connect

    Senter, Katherine G; Sukumar, Sreenivas R; Patton, Robert M; Chaum, Ed

    2015-01-01

    Diabetic retinopathy (DR) is a leading cause of blindness and common complication of diabetes. Many diabetic patients take antihypertensive drugs to prevent cardiovascular problems, but these drugs may have unintended consequences on eyesight. Six common classes of antihypertensive drug are angiotensin converting enzyme (ACE) inhibitors, alpha blockers, angiotensin receptor blockers (ARBs), -blockers, calcium channel blockers, and diuretics. Analysis of medical history data might indicate which of these drugs provide safe blood pressure control, and a literature review is often used to guide such analyses. Beyond manual reading of relevant publications, we sought to identify quantitative trends in literature from the biomedical database PubMed to compare with quantitative trends in the clinical data. By recording and analyzing PubMed search results, we found wide variation in the prevalence of each antihypertensive drug in DR literature. Drug classes developed more recently such as ACE inhibitors and ARBs were most prevalent. We also identified instances of change-over-time in publication patterns. We then compared these literature trends to a dataset of 500 diabetic patients from the UT Hamilton Eye Institute. Data for each patient included class of antihypertensive drug, presence and severity of DR. Graphical comparison revealed that older drug classes such as diuretics, calcium channel blockers, and -blockers were much more prevalent in the clinical data than in the DR and antihypertensive literature. Finally, quantitative analysis of the dataset revealed that patients taking -blockers were statistically more likely to have DR than patients taking other medications, controlling for presence of hypertension and year of diabetes onset. This finding was concerning given the prevalence of -blockers in the clinical data. We determined that clinical use of -blockers should be minimized in diabetic patients to prevent retinal damage.

  8. The growth pattern and fuel life cycle analysis of the electricity consumption of Hong Kong.

    PubMed

    To, W M; Lai, T M; Lo, W C; Lam, K H; Chung, W L

    2012-06-01

    As the consumption of electricity increases, air pollutants from power generation increase. In metropolitans such as Hong Kong and other Asian cities, the surge of electricity consumption has been phenomenal over the past decades. This paper presents a historical review about electricity consumption, population, and change in economic structure in Hong Kong. It is hypothesized that the growth of electricity consumption and change in gross domestic product can be modeled by 4-parameter logistic functions. The accuracy of the functions was assessed by Pearson's correlation coefficient, mean absolute percent error, and root mean squared percent error. The paper also applies the life cycle approach to determine carbon dioxide, methane, nitrous oxide, sulfur dioxide, and nitrogen oxide emissions for the electricity consumption of Hong Kong. Monte Carlo simulations were applied to determine the confidence intervals of pollutant emissions. The implications of importing more nuclear power are discussed.

  9. The Ocean's Carbon Factory: Ocean Composition. The Growth Patterns of Phytoplankton Species

    NASA Technical Reports Server (NTRS)

    Gregg, Watson

    2000-01-01

    According to biological data recorded by the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) satellite, the ocean contains nearly half of all the Earth's photosynthesis activity. Through photosynthesis, plant life forms use carbon from the atmosphere, and in return, plants produce the oxygen that life requires. In effect, ocean chlorophyll works like a factory, taking carbon and "manufacturing" the air we breathe. Most ocean-bound photosynthesis is performed by single-celled plants called phytoplankton. "These things are so small," according to Michael Behrenfeld, a researcher at NASA Goddard Space Flight Center, "that if you take hundreds of them and stack them end-to-end, the length of that stack is only the thickness of a penny". The humble phytoplankton species plays a vital role in balancing the amounts of oxygen and carbon dioxide in the atmosphere. Therefore, understanding exactly how phytoplankton growth works is important.

  10. The influence of interfacial growth patterns on the transmission properties of carriers through nonabrupt GaAs/Al xGa 1- xAs single barriers

    NASA Astrophysics Data System (ADS)

    Lima, M. C. A.; Junior, J. M. Pereira; Farias, G. A.; Freire, V. N.

    1995-06-01

    The influence of interfacial growth patterns on the tunelling of carriers through nonabrupt GaAs/Al xCa 1- xAs single barriers is studied. Five interfacial growth patterns are considered, all of them representative of interfacial alloy variations generated by different growth techniques. With a generalization of the scheme proposed previously by Freire et al [Superlatt. Microstruct. 1, 17 (1992)], the inter-related single barrier potential and effective mass is obtained. The envelope function equation with a position dependent kinetic energy operator is solved with a multistep scheme. The position of the resonant peaks, their peak-to-valley ratios, and the mean width of the resonance structures are shown to depend on the interfacial growth patterns.

  11. Experimental evolution alters the rate and temporal pattern of population growth in Batrachochytrium dendrobatidis, a lethal fungal pathogen of amphibians

    PubMed Central

    Voyles, Jamie; Johnson, Leah R; Briggs, Cheryl J; Cashins, Scott D; Alford, Ross A; Berger, Lee; Skerratt, Lee F; Speare, Rick; Rosenblum, Erica Bree

    2014-01-01

    Virulence of infectious pathogens can be unstable and evolve rapidly depending on the evolutionary dynamics of the organism. Experimental evolution can be used to characterize pathogen evolution, often with the underlying objective of understanding evolution of virulence. We used experimental evolution techniques (serial transfer experiments) to investigate differential growth and virulence of Batrachochytrium dendrobatidis (Bd), a fungal pathogen that causes amphibian chytridiomycosis. We tested two lineages of Bd that were derived from a single cryo-archived isolate; one lineage (P10) was passaged 10 times, whereas the second lineage (P50) was passaged 50 times. We quantified time to zoospore release, maximum zoospore densities, and timing of zoospore activity and then modeled population growth rates. We also conducted exposure experiments with a susceptible amphibian species, the common green tree frog (Litoria caerulea) to test the differential pathogenicity. We found that the P50 lineage had shorter time to zoospore production (Tmin), faster rate of sporangia death (ds), and an overall greater intrinsic population growth rate (λ). These patterns of population growth in vitro corresponded with higher prevalence and intensities of infection in exposed Litoria caerulea, although the differences were not significant. Our results corroborate studies that suggest that Bd may be able to evolve relatively rapidly. Our findings also challenge the general assumption that pathogens will always attenuate in culture because shifts in Bd virulence may depend on laboratory culturing practices. These findings have practical implications for the laboratory maintenance of Bd isolates and underscore the importance of understanding the evolution of virulence in amphibian chytridiomycosis. PMID:25478154

  12. PubMedMiner: Mining and Visualizing MeSH-based Associations in PubMed

    PubMed Central

    Zhang, Yucan; Sarkar, Indra Neil; Chen, Elizabeth S.

    2014-01-01

    The exponential growth of biomedical literature provides the opportunity to develop approaches for facilitating the identification of possible relationships between biomedical concepts. Indexing by Medical Subject Headings (MeSH) represent high-quality summaries of much of this literature that can be used to support hypothesis generation and knowledge discovery tasks using techniques such as association rule mining. Based on a survey of literature mining tools, a tool implemented using Ruby and R – PubMedMiner – was developed in this study for mining and visualizing MeSH-based associations for a set of MEDLINE articles. To demonstrate PubMedMiner’s functionality, a case study was conducted that focused on identifying and comparing comorbidities for asthma in children and adults. Relative to the tools surveyed, the initial results suggest that PubMedMiner provides complementary functionality for summarizing and comparing topics as well as identifying potentially new knowledge. PMID:25954472

  13. Effects of growth patterns and dietary protein levels during rearing of broiler breeders on fertility, hatchability, embryonic mortality, and offspring performance.

    PubMed

    van Emous, R A; Kwakkel, R P; van Krimpen, M M; van den Brand, H; Hendriks, W H

    2015-04-01

    The objective of this study was to determine the effects of different growth patterns and dietary crude protein levels during rearing in broiler breeder females on fertility, hatchability, embryonic mortality, and offspring performance. A 2×3 factorial arrangement of treatments was used, with 2 growth patterns to reach a target body weight at 20 wk of age of 2,200 g (standard=standard growth pattern) or 2,400 g (high=high growth pattern), and 3 dietary protein levels (high=crude protein, high), (medium=crude protein, medium), and low=crude protein, low). Fresh egg composition and organ development in hatchlings were determined. Offspring of the different groups were reared until an age of 34 d and feed intake, body weight gain, mortality, and carcass composition were determined. In 29-wk-old high growth pattern breeders compared to standard growth pattern breeders, fertility and hatchability of set eggs were increased; embryonic mortality between d 1 and 9 was decreased whereas hatchability of fertile eggs was not affected. Breeders fed the medium crude protein diet showed a decreased hatchability of fertile eggs caused by an increased embryonic mortality between d 18 and 21 compared to breeders fed the high crude protein and low crude protein diets. Offspring of 29-wk-old high growth pattern breeders tended (P=0.059) to have a higher body weight at d 34 than offspring of standard growth pattern breeders, which was achieved by a tendency to a higher body weight gain (P=0.057). Offspring of breeders fed the medium and low crude protein diet showed a higher feed intake between d 18 and 27 and during the total growth period, as compared to offspring of high crude protein breeders. Male broilers of low crude protein breeders had higher breast meat yield than male broilers of high crude protein breeders, while breast meat yield of female broilers was not affected by dietary protein levels. This experiment showed that a higher growth pattern during the rearing period

  14. Growth, patterning and alignment of organolead iodide perovskite nanowires for optoelectronic devices

    NASA Astrophysics Data System (ADS)

    Deng, Hui; Dong, Dongdong; Qiao, Keke; Bu, Lingling; Li, Bing; Yang, Dun; Wang, Hong-En; Cheng, Yibing; Zhao, Zhixin; Tang, Jiang; Song, Haisheng

    2015-02-01

    Organolead halide perovskites are becoming intriguing materials applied in optoelectronics. In the present work, organolead iodide perovskite (OIP) nanowires (NWs) have been fabricated by a one step self-assembly method. The controllable NW distributions were implemented by a series of facile techniques: monolayer and small diameter NWs were prepared by precursor concentration tuning; NW patterning was achieved via selected area treatment assisted by a mask; NW alignment was implemented by modified evaporation-induced self-assembly (EISA). The synthesized multifunctional NWs were further applied in photodetectors (PDs) and solar cells as application demos. The PD performances have reached 1.32 AW-1 for responsivity, 2.5 × 1012 Jones for detectivity and 0.3 ms for response speed, superior to OIP films and other typical inorganic NW based PD performances. An energy conversion efficiency of ~2.5% has been obtained for NW film based solar cells. The facile fabrication process, controllable distribution and optoelectronic applications make the OIP NWs promising building blocks for future optoelectronics, especially for low dimensional devices.Organolead halide perovskites are becoming intriguing materials applied in optoelectronics. In the present work, organolead iodide perovskite (OIP) nanowires (NWs) have been fabricated by a one step self-assembly method. The controllable NW distributions were implemented by a series of facile techniques: monolayer and small diameter NWs were prepared by precursor concentration tuning; NW patterning was achieved via selected area treatment assisted by a mask; NW alignment was implemented by modified evaporation-induced self-assembly (EISA). The synthesized multifunctional NWs were further applied in photodetectors (PDs) and solar cells as application demos. The PD performances have reached 1.32 AW-1 for responsivity, 2.5 × 1012 Jones for detectivity and 0.3 ms for response speed, superior to OIP films and other typical inorganic

  15. Changes in patterns of growth and nutritional anthropometry in two rural modernizing Papua New Guinea communities.

    PubMed

    Norgan, N G

    1995-01-01

    In Papua New Guinea growth is slow and adult body size is small. This is often considered an adaptation to the low energy and nutrient densities of the diets in which tubers and root crops predominate. Social and economic change have been a feature of Papua New Guinea, particularly in recent times. In 1969 the human biology of two contrasting communities, one coastal with a long interaction with external influences and cash cropping, the other a highland community with a history of more recent contacts, was investigated. In 1984 repeat measurements of nutritional anthropometry were made on the villagers and those born in the previous 14 years. The coastal boys and girls were taller and heavier in 1984 compared with 1969 but remained below the 5th percentile of reference North American data. Increases were also found in the highland children, particularly girls, but significantly lower means were found in children under 2 years. Although stunting was less common in the coastal children in 1984, 156 cases (37%) versus 175 cases (43%) (chi 2 = 7.69, rho < 0.05), wasting increased in prevalence from 11 cases (3%) to 20 cases (5%) (n.s.), either because of recent food shortages or because height change was greater than weight change. Stunting rose by 3% to 53% (165 cases) in highland children (chi 2 = 7.24, p < 0.05). In adults, heights were 2-3 cm greater in 1984 than 1969, and weights 2-3 kg greater, with peak differences in the 30-39-year-olds. The percentage of coastal women with body mass indices of less than 18.5 kg/m2 fell from 32% to 15% (chi 2 = 27.4, p < 0.01). Mid-upper arm circumferences and triceps skinfolds were significantly higher in all groups. National and regional data suggest that the communities were better off in 1984 than 1969, but social and economic changes were associated with variable benefits in growth and nutritional status. PMID:8815777

  16. Using Noun Phrases for Navigating Biomedical Literature on Pubmed: How Many Updates Are We Losing Track of?

    PubMed Central

    Srikrishna, Devabhaktuni; Coram, Marc A.

    2011-01-01

    Author-supplied citations are a fraction of the related literature for a paper. The “related citations” on PubMed is typically dozens or hundreds of results long, and does not offer hints why these results are related. Using noun phrases derived from the sentences of the paper, we show it is possible to more transparently navigate to PubMed updates through search terms that can associate a paper with its citations. The algorithm to generate these search terms involved automatically extracting noun phrases from the paper using natural language processing tools, and ranking them by the number of occurrences in the paper compared to the number of occurrences on the web. We define search queries having at least one instance of overlap between the author-supplied citations of the paper and the top 20 search results as citation validated (CV). When the overlapping citations were written by same authors as the paper itself, we define it as CV-S and different authors is defined as CV-D. For a systematic sample of 883 papers on PubMed Central, at least one of the search terms for 86% of the papers is CV-D versus 65% for the top 20 PubMed “related citations.” We hypothesize these quantities computed for the 20 million papers on PubMed to differ within 5% of these percentages. Averaged across all 883 papers, 5 search terms are CV-D, and 10 search terms are CV-S, and 6 unique citations validate these searches. Potentially related literature uncovered by citation-validated searches (either CV-S or CV-D) are on the order of ten per paper – many more if the remaining searches that are not citation-validated are taken into account. The significance and relationship of each search result to the paper can only be vetted and explained by a researcher with knowledge of or interest in that paper. PMID:21935487

  17. [Effects of mulching patterns on soil water, broomcorn millet growth, photosynthetic charac- teristics and yield in the dryland of Loess Plateau in China].

    PubMed

    Su, Wang; Zhang, Yan-Ping; Qu, Yang; Li, Cui; Miao, Jia-Yuan; Gao, Xiao-Li; Liu, Jian-Hua; Feng, Bai-Li

    2014-11-01

    The objective of this study was to explore the effects of mulching patterns on soil water, growth, photosynthetic characteristics, grain yield and water use efficiency (WUE) of broomcorn millet in the dryland of Loess Plateau in China. In a three-year field experiment from 2011 to 2013, we compared four different mulching patterns with traditional plat planting (no mulching) as the control (CK). The mulching patterns included W ridge covered with common plastic film + intredune covered with straw (SG), common ridge covered with common plastic film + intredune covered with straw (LM), double ridges covered with common plastic film + intredune covered with straw (QM), and the traditional plat planting covered with straw (JG). The results showed that the soil water storage in 0-100 cm layer was significantly higher in all mulching patterns than in CK, particularly in SG then followed by LM, QM and JG, and the differences among the mulching patterns reached a significant level at the different growth stages of broomcorn millet. Among all mulching patterns, SG had the greatest effect on the growth and photosynthesis of broomcorn millet, respectively increasing the yield and WUE by 55.9% and 64.9% over CK, and the differences among the mulching patterns also reached a significant level. Therefore, SG was recommended as an efficient planting pattern for broomcorn millet production in the dryland of Loess Plateau in China.

  18. b-FGF Induces Corneal Blood and Lymphatic Growth in a Spatially Distinct Pattern

    PubMed Central

    Hajrasouliha, Amir R.; Sadrai, Zahra; Chauhan, Sunil K.; Dana, Reza

    2013-01-01

    Purpose To study the spatial variances in ligand expression and angiogenic effect in response to the inflammatory response induced by b-FGF. Methods b-FGF micropellets (80ng) were implanted in the temporal side of the cornea of Balbc/c mice. On days 1, 3, and 7 blood (heme) and lymph-angiogenesis were observed by immunofluorescence staining of corneal flat mounts with LYVE-1 and CD31 to identify lymphatic and blood vessels, respectively. A second group of corneas were harvested for quantitative RT-PCR. Each cornea was divided in two different area defines as (i) pre-pellet area and (ii) opposite-pellet area. Expression of VEGF ligands were evaluated using Real-time PCR in each respective zone. Results Blood vessels grew into the cornea from the pre-pellet area while corneal lymphatic vessels grew from the opposite-pellet area toward the center of the cornea. VEGF-A was upregulated in the pre-pellet while VEGF-D expression was mostly observed in the opposite-pellet area. VEGF-C level increased simultaneously in both areas. Conclusion A single inducing factor, i.e., b-FGF, may simultaneously provoke heme-and lymph-angiogenesis in different locations of the cornea through differential expression of VEGF ligands. This distinctive spatial pattern should be considered while evaluating the corneal predilection for inflammation beyond that which is directly visible by slit lamp examination. PMID:22467003

  19. Universal scaling rules predict evolutionary patterns of myogenesis in species with indeterminate growth

    PubMed Central

    Johnston, Ian A.; Kristjánsson, Bjarni K.; Paxton, Charles G. P.; Vieira, Vera L. A.; Macqueen, Daniel J.; Bell, Michael A.

    2012-01-01

    Intraspecific phenotypic variation is ubiquitous and often associated with resource exploitation in emerging habitats. For example, reduced body size has evolved repeatedly in Arctic charr (Salvelinus alpinus L.) and threespine stickleback (Gasterosteus aculeatus L.) across post-glacial habitats of the Northern Hemisphere. Exploiting these models, we examined how body size and myogenesis evolve with respect to the ‘optimum fibre size hypothesis’, which predicts that selection acts to minimize energetic costs associated with ionic homeostasis by optimizing muscle fibre production during development. In eight dwarf Icelandic Arctic charr populations, the ultimate production of fast-twitch muscle fibres (FNmax) was only 39.5 and 15.5 per cent of that in large-bodied natural and aquaculture populations, respectively. Consequently, average fibre diameter (FD) scaled with a mass exponent of 0.19, paralleling the relaxation of diffusional constraints associated with mass-specific metabolic rate scaling. Similar reductions in FNmax were observed for stickleback, including a small-bodied Alaskan population derived from a larger-bodied oceanic stock over a decadal timescale. The results suggest that in species showing indeterminate growth, body size evolution is accompanied by strong selection for fibre size optimization, theoretically allowing resources saved from ionic homeostasis to be allocated to other traits affecting fitness, including reproduction. Gene flow between small- and large-bodied populations residing in sympatry may counteract the evolution of this trait. PMID:22237905

  20. Exercise training alters DNA methylation patterns in genes related to muscle growth and differentiation in mice.

    PubMed

    Kanzleiter, Timo; Jähnert, Markus; Schulze, Gunnar; Selbig, Joachim; Hallahan, Nicole; Schwenk, Robert Wolfgang; Schürmann, Annette

    2015-05-15

    The adaptive response of skeletal muscle to exercise training is tightly controlled and therefore requires transcriptional regulation. DNA methylation is an epigenetic mechanism known to modulate gene expression, but its contribution to exercise-induced adaptations in skeletal muscle is not well studied. Here, we describe a genome-wide analysis of DNA methylation in muscle of trained mice (n = 3). Compared with sedentary controls, 2,762 genes exhibited differentially methylated CpGs (P < 0.05, meth diff >5%, coverage >10) in their putative promoter regions. Alignment with gene expression data (n = 6) revealed 200 genes with a negative correlation between methylation and expression changes in response to exercise training. The majority of these genes were related to muscle growth and differentiation, and a minor fraction involved in metabolic regulation. Among the candidates were genes that regulate the expression of myogenic regulatory factors (Plexin A2) as well as genes that participate in muscle hypertrophy (Igfbp4) and motor neuron innervation (Dok7). Interestingly, a transcription factor binding site enrichment study discovered significantly enriched occurrence of CpG methylation in the binding sites of the myogenic regulatory factors MyoD and myogenin. These findings suggest that DNA methylation is involved in the regulation of muscle adaptation to regular exercise training.

  1. Patterns and rates of enamel growth in the molar teeth of early hominids.

    PubMed

    Beynon, A D; Wood, B A

    A recent study of the surface manifestation of incremental lines associated with enamel formation suggested that the crowns of early hominid incisor teeth were formed more rapidly than those of modern humans. In the absence of comparative data, the authors were forced to assume that enamel increments in fossil teeth were similar to those in modern humans. We have used evidence from the fractured surfaces of molar teeth to deduce estimates for both long- and short-period incremental growth markers within enamel in east African 'robust' australopithecine and early Homo teeth. We conclude that in these early hominids, crown formation times in posterior teeth, particularly in the large thick enamelled molar teeth of the east African 'robust' australopithecines, were shorter than those of modern humans. This evidence, considered together with data on crown and root formation times in modern apes, suggests that the posterior teeth in these hominids both formed and erupted more rapidly than those of modern man. These results have implications for attempts to assess dental and skeletal maturity in hominids. PMID:3104794

  2. Growth patterns and scaling laws governing AIDS epidemic in Brazilian cities.

    PubMed

    Antonio, Fernando Jose; de Picoli, Sergio; Teixeira, Jorge Juarez Vieira; Mendes, Renio dos Santos

    2014-01-01

    Brazil holds approximately 1/3 of population living infected with AIDS (acquired immunodeficiency syndrome) in Central and South Americas, and it was also the first developing country to implement a large-scale control and intervention program against AIDS epidemic. In this scenario, we investigate the temporal evolution and current status of the AIDS epidemic in Brazil. Specifically, we analyze records of annual absolute frequency of cases for more than 5000 cities for the first 33 years of the infection in Brazil. We found that (i) the annual absolute frequencies exhibit a logistic-type growth with an exponential regime in the first few years of the AIDS spreading; (ii) the actual reproduction number decaying as a power law; (iii) the distribution of the annual absolute frequencies among cities decays with a power law behavior; (iv) the annual absolute frequencies and the number of inhabitants have an allometric relationship; (v) the temporal evolution of the annual absolute frequencies have different profile depending on the average annual absolute frequencies in the cities. These findings yield a general quantitative description of the AIDS infection dynamics in Brazil since the beginning. They also provide clues about the effectiveness of treatment and control programs against the infection, that has had a different impact depending on the number of inhabitants of cities. In this framework, our results give insights into the overall dynamics of AIDS epidemic, which may contribute to select empirically accurate models. PMID:25340796

  3. Linking sewage pollution and water quality to spatial patterns of Porites lobata growth anomalies in Puako, Hawaii.

    PubMed

    Yoshioka, Reyn M; Kim, Catherine J S; Tracy, Allison M; Most, Rebecca; Harvell, C Drew

    2016-03-15

    Sewage pollution threatens the health of coastal populations and ecosystems, including coral reefs. We investigated spatial patterns of sewage pollution in Puako, Hawaii using enterococci concentrations and δ(15)N Ulva fasciata macroalgal bioassays to assess relationships with the coral disease Porites lobata growth anomalies (PGAs). PGA severity and enterococci concentrations were high, spatially variable, and positively related. Bioassay algal δ(15)N showed low sewage pollution at the reef edge while high values of resident algae indicated sewage pollution nearshore. Neither δ(15)N metric predicted PGA measures, though bioassay δ(15)N was negatively related to coral cover. Furthermore, PGA prevalence was much higher than previously recorded in Hawaii and the greater Indo-Pacific, highlighting Puako as an area of concern. Although further work is needed to resolve the relationship between sewage pollution and coral cover and disease, these results implicate sewage pollution as a contributor to diminished reef health.

  4. The pattern of growth observed for Clostridium botulinum type A1 strain ATCC 19397 is influenced by nutritional status and quorum sensing: a modelling perspective

    PubMed Central

    Ihekwaba, Adaoha E. C.; Mura, Ivan; Peck, Michael W.; Barker, G. C.

    2015-01-01

    Botulinum neurotoxins (BoNTs) produced by the anaerobic bacterium Clostridium botulinum are the most poisonous substances known to mankind. However, toxin regulation and signals triggering synthesis as well as the regulatory network and actors controlling toxin production are unknown. Experiments show that the neurotoxin gene is growth phase dependent for C. botulinum type A1 strain ATCC 19397, and toxin production is influenced both by culture conditions and nutritional status of the medium. Building mathematical models to describe the genetic and molecular machinery that drives the synthesis and release of BoNT requires a simultaneous description of the growth of the bacterium in culture. Here, we show four plausible modelling options which could be considered when constructing models describing the pattern of growth observed in a botulinum growth medium. Commonly used bacterial growth models are unsuitable to fit the pattern of growth observed, since they only include monotonic growth behaviour. We find that a model that includes both the nutritional status and the ability of the cells to sense their surroundings in a quorum-sensing manner is most successful at explaining the pattern of growth obtained for C. botulinum type A1 strain ATCC 19397. PMID:26449712

  5. The pattern of growth observed for Clostridium botulinum type A1 strain ATCC 19397 is influenced by nutritional status and quorum sensing: a modelling perspective.

    PubMed

    Ihekwaba, Adaoha E C; Mura, Ivan; Peck, Michael W; Barker, G C

    2015-12-01

    Botulinum neurotoxins (BoNTs) produced by the anaerobic bacterium Clostridium botulinum are the most poisonous substances known to mankind. However, toxin regulation and signals triggering synthesis as well as the regulatory network and actors controlling toxin production are unknown. Experiments show that the neurotoxin gene is growth phase dependent for C. botulinum type A1 strain ATCC 19397, and toxin production is influenced both by culture conditions and nutritional status of the medium. Building mathematical models to describe the genetic and molecular machinery that drives the synthesis and release of BoNT requires a simultaneous description of the growth of the bacterium in culture. Here, we show four plausible modelling options which could be considered when constructing models describing the pattern of growth observed in a botulinum growth medium. Commonly used bacterial growth models are unsuitable to fit the pattern of growth observed, since they only include monotonic growth behaviour. We find that a model that includes both the nutritional status and the ability of the cells to sense their surroundings in a quorum-sensing manner is most successful at explaining the pattern of growth obtained for C. botulinum type A1 strain ATCC 19397.

  6. Self-assembly based nanometer-scale patterning for nanowire growth

    NASA Astrophysics Data System (ADS)

    Chandramohan, Abhishek; Sibirev, Nikolai; Dubrovskii, Vladimir G.; Mendis, Budhika; Petty, Mike C.; Gallant, Andrew J.; Zeze, Dagou A.

    2015-08-01

    Periodic nanostructure arrays have been ubiquitously exploited lately due to their properties and prospective applications in production of templates for self-induced and gold (Au)-catalysed nanowires (NWs), because this approach is relatively cheap, time-efficient and do not require electron beam lithography. The technique consists creating nanoholes in SiO2 to expose the silicon Si (111) beneath where self-induced NWs can nucleate, while nanodots deposited onto the Si (111) surface serve as catalyst seeds. For Au-catalysed NWs, a monolayer of self-assembled polystyrene nanospheres (PNS 300nm) was created on a 2 inch Si wafer by spin coating and later etched for a short time before a very thin Au-catalyst layer was deposited. In turn, for self-induced, PNS monolayer was created onto a SiO2-Si substrate. A longer etch was required to reduce PNS diameter significantly to leave relatively larger spacing where chromium is blanket deposited. PNS were lifted off by sonicating the samples in toluene produce the periodic arrays of nanodots and nanoholes, respectively. The underlying SiO2 was etched further through the nanoholes to uncover the Si below. 200 nm holes and 30-70 nm dots were demonstrated through the bespoke methods. The patterned substrates served as master templates, subsequently copied using polydimethylsiloxane (PDMS) to produce a flexible stamp for nanoimprint lithography. A bilayer resist lift off process was developed to print the replicated nanodots or nanoholes on large-area substrates onto which III-V NWs can be grown.

  7. Insulin-like growth factor-1 content and pattern of expression correlates with histopathologic grade in diffusely infiltrating astrocytomas.

    PubMed

    Hirano, H; Lopes, M B; Laws, E R; Asakura, T; Goto, M; Carpenter, J E; Karns, L R; VandenBerg, S R

    1999-04-01

    Studies of experimental tumorigenesis have strongly implicated signaling of the insulin-like growth factor 1 (IGF-1) as a key component in astrocytic neoplasia; however, its role in the growth of low-grade and malignant human tumors is not well understood. Correlative analyses of IGF-1, p53, and Ki-67 (MIB-1) immunohistochemistry and IGF-1 receptor (IGF-1R) mRNA expression were performed to examine the cellular pattern of IGF-1 signaling in 39 cases of astrocytoma (World Health Organization grades II-IV). Tumor cells expressing IGF-1 and IGF-1R were present in all tumor grades. The proportion of tumor cells that expressed IGF-1 correlated with both histopathologic grade and Ki-67 labeling indices, while expression of IGF-1R mRNA correlated with Ki-67 indices. In cases where stereotactic tissue sampling could be identified with a specific tumor area by neuroimaging features, the numbers of IGF-1 immunoreactive cells correlated with the tumor zones of highest cellularity and Ki-67 labeling. In glioblastomas, the localization of IGF-1 immunoreactivity was notable for several features: frequent accentuation in the perivascular tumor cells surrounding microvascular hyperplasia; increased levels in reactive astrocytes at the margins of tumor infiltration; and selective expression in microvascular cells exhibiting endothelial/pericytic hyperplasia. IGF-1R expression was particularly prominent in tumor cells adjacent to both microvascular hyperplasia and palisading necrosis. These data suggest that IGF-1 signaling occurs early in astroglial tumorigenesis in the setting of cell proliferation. The distinctive correlative patterns of IGF-1 and IGF-1R expression in glioblastomas also suggest that IGF-1 signaling has an association with the development of malignant phenotypes related to aberrant angiogenesis and invasive tumor interactions with reactive brain.

  8. Changing exhumation patterns during Cenozoic growth and glaciation of the Alaska Range: Insights from detrital thermochronology and geochronology

    NASA Astrophysics Data System (ADS)

    Lease, Richard O.; Haeussler, Peter J.; O'Sullivan, Paul

    2016-04-01

    Cenozoic growth of the Alaska Range created the highest topography in North America, but the space-time pattern and drivers of exhumation are poorly constrained. We analyzed U/Pb and fission-track double dates of detrital zircon and apatite grains from 12 catchments that span a 450 km length of the Alaska Range to illuminate the timing and extent of exhumation during different periods. U/Pb ages indicate a dominant Late Cretaceous to Oligocene plutonic provenance for the detrital grains, with only a small percentage of grains recycled from the Mesozoic and Paleozoic sedimentary cover. Fission-track ages record exhumation during Alaska Range growth and incision and reveal three distinctive patterns. First, initial Oligocene exhumation was focused in the central Alaska Range at ~30 Ma and expanded outward along the entire length of the range until 18 Ma. Oligocene exhumation, coeval with initial Yakutat microplate collision >600 km to the southeast, suggests a far-field response to collision that was localized by the Denali Fault within a weak Mesozoic suture zone. Second, the variable timing of middle to late Miocene exhumation suggests independently evolving histories influenced by local structures. Time-transgressive cooling ages suggest successive rock uplift and erosion of Mounts Foraker (12 Ma) through Denali (6 Ma) as crust was advected through a restraining bend in the Denali Fault and indicate a long-term slip rate ~4 mm/yr. Third, Pliocene exhumation is synchronous (3.7-2.7 Ma) along the length of the Alaska Range but only occurs in high-relief, glacier-covered catchments. Pliocene exhumation may record an acceleration in glacial incision that was coincident with the onset of Northern Hemisphere glaciation.

  9. A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

    SciTech Connect

    Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.; Vo, Huy; Uervirojnangkoorn, Monarin; Brunger, Axel T.; Berger, James M.

    2015-09-26

    Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called `fixed-target' sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessary to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15µm) loaded into the chips yielded a complete, high-resolution (<1.6Å) data set sufficient to determine a high-quality structure by molecular replacement. The features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.

  10. A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

    SciTech Connect

    Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.; Vo, Huy; Uervirojnangkoorn, Monarin; Brunger, Axel T.; Berger, James M.

    2015-09-26

    A highly X-ray-transparent, silicon nitride-based device has been designed and fabricated to harvest protein microcrystals for high-resolution X-ray diffraction data collection using microfocus beamlines and XFELs. Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called ‘fixed-target’ sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessary to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. The features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.

  11. A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

    SciTech Connect

    Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.; Vo, Huy; Uervirojnangkoorn, Monarin; Brunger, Axel T.; Berger, James M.

    2015-08-11

    Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called `fixed-target' sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessary to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. In addition, the features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.

  12. A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

    DOE PAGESBeta

    Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.; Vo, Huy; Uervirojnangkoorn, Monarin; Brunger, Axel T.; Berger, James M.

    2015-08-11

    Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called `fixed-target' sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessarymore » to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. In addition, the features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.« less

  13. A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

    PubMed Central

    Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.; Vo, Huy; Uervirojnangkoorn, Monarin; Brunger, Axel T.; Berger, James M.

    2015-01-01

    Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called ‘fixed-target’ sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessary to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. The features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs. PMID:26457423

  14. National patterns in human papillomavirus vaccination: an analysis of the National Survey of Family Growth.

    PubMed

    Sadigh, Gelareh; Dempsey, Amanda F; Ruffin, Mack; Resnicow, Ken; Carlos, Ruth C

    2012-02-01

    Human papillomavirus (HPV) vaccine has shown effectiveness for girls and young women. Despite this, there are population disparities in vaccine utilization rates. The purpose of this study was to evaluate maternal correlates of HPV vaccination among their adolescent daughters using a nationally-representative population-based sample, emphasizing race/ethnicity-specific disparities and barriers. Mothers of 9-18 y-old girls having heard of HPV vaccine and completing the HPV vaccine survey module from the 2006-2008 National Survey of Family Growth (NSFG) (n = 444) were analyzed for maternally-reported adolescent HPV vaccination and maternal intent to vaccinate her adolescent daughter if no dose had been received. Correlates of uptake and intent were examined using multivariate logistic regression. 27% of mothers (n = 98) reported that their daughters were vaccinated against HPV. Independent correlates of vaccination included African-American race (adjusted odds ratio (AOR),0.29; 95% confidence interval (CI),0.11-0.77), and living below the poverty level (AOR,4.43; 95%CI, 1.53-12.82). 46% (n = 152) of mothers of non-vaccinated daughters intended to vaccinate them. Correlates of maternal intention included maternal pelvic exam history (AOR,0.06; 95%CI, 0.007-0.51), multiple male lifetime sexual partners (AOR,3.22 ; 95% CI, 1.34-7.76), religiosity (AOR,0.37; 95% CI,0.16-0.87) and acceptability of premarital sex among 18 y-olds (AOR,2.45; 95% CI, 1.16-5.20). In conclusion, HPV vaccination initiation among adolescent daughters of mothers participating in the NSFG continues to lag among African-American participants. However, no racial/ethnic differences in maternal intent-to-vaccinate her daughter were detected. Future interventions need to address specific maternal barriers to vaccine uptake and how these may differ from vaccine intention.

  15. Architectural elements and growth patterns of submarine channels: Application to hydrocarbon exploration

    SciTech Connect

    Clark, J.D.; Pickering, K.T.

    1996-02-01

    Modern and ancient submarine channels show a wide range of architectural styles. Architectural element analysis is a useful descriptive means to characterize the type of channel fill, show the interconnectivity and lateral continuity of sand bodies, and interpret the causal sedimentary processes. This paper combines a review of the literature on submarine channels with new observations and analysis, and proposes architectural element models for submarine channels, in particular, demonstrating how these models can be applied to interpreting the sequential fill of ancient submarine channels. Data for the dimensions and degrees of lateral continuity and vertical connectivity of channel elements, such as those giving rise to reservoir heterogeneities in hydrocarbon exploration, are presented for a variety of examples of architectural elements, providing quantitative information for reservoir analog models. Sequence analysis; a development of these techniques, in particular their application to smaller scale features of turbidite systems, is described in Pickering et al.. A comparison of element analysis schemes for deep-water deposits. The characterization of outcrops of ancient deposits into their component elements at a variety of scales may help unravel complex depositional histories and help in understanding the development of the growth stages within turbidite systems. Studies of modern submarine channel data have shown that sinuosity and gradient are related, thereby permitting the identification of high- to low-sinuosity channel systems. It is important to attempt to link such observations to the different processes that may characterize, for example, low- vs. high-sinuosity deep-water channels, which will be particularly useful in evaluating the location and development of sand-prone hydrocarbon reservoirs within such systems.

  16. Fetal and infant growth patterns of the mandibular symphysis in modern humans and chimpanzees (Pan troglodytes).

    PubMed

    Coquerelle, Michael; Bookstein, Fred L; Braga, José; Halazonetis, Demetrios J; Weber, Gerhard W

    2010-11-01

    Comparison of the early development of the mandibular symphysis between primates and modern humans is of particular interest in human palaeontology. Using geometric morphometric methods, we explored and compared the ontogenetic shape changes of 14 chimpanzee mandibles (Pan troglodytes) against 66 human CT-scanned mandibles over the age range from fetal life to the complete emergence of the deciduous dentition in a visualization incorporating the deciduous tooth arrangement. The results reveal that the symphysis is anteriorly inclined in the youngest chimpanzee fetuses but develops an increasingly vertical orientation up until birth. At the same time, the anterior teeth reorient before a vertical emergence, and a symphyseal tuber appears on the labial side. When the deciduous canine emerges, the symphysis inclines anteriorly again, exhibiting the adult characteristic slope. These two phases are characterized by a repositioning of the simian shelf. Unlike chimpanzees, the human symphysis remains vertical throughout fetal development. However, the combination of morphological changes observed in chimpanzee fetuses is similar to that of modern humans after birth, as the mental region projects forward. By elongating the alveolar process, the inclination of the chimpanzee symphysis could be a key event for emergence of the deciduous canine, as space is lacking at the alveolar ridge in a vertical symphysis once the deciduous incisors and molars have emerged. The repositioning of the simian shelf suggests that the suprahyoid muscles have a significant influence on the anterior growth of the symphysis. The anteroposterior positioning of the basal symphysis in both species may be related to hyoid bone position during ontogeny.

  17. Fetal and infant growth patterns of the mandibular symphysis in modern humans and chimpanzees (Pan troglodytes)

    PubMed Central

    Coquerelle, Michael; Bookstein, Fred L; Braga, José; Halazonetis, Demetrios J; Weber, Gerhard W

    2010-01-01

    Comparison of the early development of the mandibular symphysis between primates and modern humans is of particular interest in human palaeontology. Using geometric morphometric methods, we explored and compared the ontogenetic shape changes of 14 chimpanzee mandibles (Pan troglodytes) against 66 human CT-scanned mandibles over the age range from fetal life to the complete emergence of the deciduous dentition in a visualization incorporating the deciduous tooth arrangement. The results reveal that the symphysis is anteriorly inclined in the youngest chimpanzee fetuses but develops an increasingly vertical orientation up until birth. At the same time, the anterior teeth reorient before a vertical emergence, and a symphyseal tuber appears on the labial side. When the deciduous canine emerges, the symphysis inclines anteriorly again, exhibiting the adult characteristic slope. These two phases are characterized by a repositioning of the simian shelf. Unlike chimpanzees, the human symphysis remains vertical throughout fetal development. However, the combination of morphological changes observed in chimpanzee fetuses is similar to that of modern humans after birth, as the mental region projects forward. By elongating the alveolar process, the inclination of the chimpanzee symphysis could be a key event for emergence of the deciduous canine, as space is lacking at the alveolar ridge in a vertical symphysis once the deciduous incisors and molars have emerged. The repositioning of the simian shelf suggests that the suprahyoid muscles have a significant influence on the anterior growth of the symphysis. The anteroposterior positioning of the basal symphysis in both species may be related to hyoid bone position during ontogeny. PMID:20807267

  18. Evolution of morphological novelty: a phylogenetic analysis of growth patterns in Streptocarpus (Gesneriaceae).

    PubMed

    Möller, M; Cronk, Q C

    2001-05-01

    Streptocarpus shows great variation in vegetative architecture. In some species a normal shoot apical meristem never forms and the entire vegetative plant body may consist of a single giant cotyledon, which may measure up to 0.75 m (the unifoliate type) or with further leaves arising from this structure (the rosulate type). A molecular phylogeny of 87 taxa (77 Streptocarpus species, seven related species, and three outgroup species) using the internal transcribed spacers and 5.8S region of nuclear ribosomal DNA suggests that Streptocarpus can be divided into two major clades. One of these broadly corresponds to the caulescent group (with conventional shoot architecture) classified as subgenus Streptocarpella, whereas the other is mainly composed of acaulescent species with unusual architecture (subgenus Streptocarpus). Some caulescent species (such as S. papangae) are anomalously placed with the acaulescent clade. Available cytological data are, however, completely congruent with the two major clades: the caulescent clade is x = 15 and the acaulescent clade (including the caulescent S. papangae) is x = 16 (or polyploid multiples of 16). The genera Linnaeopsis, Saintpaulia, and Schizoboea are nested within Streptocarpus. The sequenced region has evolved, on average, 2.44 times faster in the caulescent clade than in the acaulescent clade and this is associated with the more rapid life cycle of the caulescents. Morphological variation in plant architecture within the acaulescent clade is homoplastic and does not appear to have arisen by unique abrupt changes. Instead, rosulate and unifoliate growth forms have evolved several times, reversals have occurred, and intermediate architectures are found. An underlying developmental plasticity seems to be a characteristic of the acaulescent clade and is reflected in a great lability of form. PMID:11430652

  19. Nerve growth factor regulates the firing patterns and synaptic composition of motoneurons.

    PubMed

    Davis-López de Carrizosa, María A; Morado-Díaz, Camilo J; Morcuende, Sara; de la Cruz, Rosa R; Pastor, Angel M

    2010-06-16

    Target-derived neurotrophins exert powerful synaptotrophic actions in the adult brain and are involved in the regulation of different forms of synaptic plasticity. Target disconnection produces a profound synaptic stripping due to the lack of trophic support. Consequently, target reinnervation leads to synaptic remodeling and restoration of cellular functions. Extraocular motoneurons are unique in that they normally express the TrkA neurotrophin receptor in the adult, a feature not seen in other cranial or spinal motoneurons, except after lesions such as axotomy or in neurodegenerative diseases like amyotrophic lateral sclerosis. We investigated the effects of nerve growth factor (NGF) by retrogradely delivering this neurotrophin to abducens motoneurons of adult cats. Axotomy reduced the density of somatic boutons and the overall tonic and phasic firing modulation. Treatment with NGF restored synaptic inputs and firing modulation in axotomized motoneurons. When K252a, a selective inhibitor of tyrosine kinase activity, was applied to specifically test TrkA effects, the NGF-mediated restoration of synapses and firing-related parameters was abolished. Discharge variability and recruitment threshold were, however, increased by NGF compared with control or axotomized motoneurons. Interestingly, these parameters returned to normal following application of REX, an antibody raised against neurotrophin receptor p75 (p75(NTR)). In conclusion, NGF, acting retrogradely through TrkA receptors, supports afferent boutons and regulates the burst and tonic signals correlated with eye movements. On the other hand, p75(NTR) activation regulates recruitment threshold, which impacts on firing regularity. To our knowledge, this is the first report showing powerful synaptotrophic effects of NGF on motoneurons in vivo.

  20. Patterned growth of p-type MoS2 atomic layers using sol-gel as precursor

    DOE PAGESBeta

    Zheng, Wei; Lin, Junhao; Feng, Wei; Xiao, Kai; Qiu, Yunfeng; Chen, XiaoShuang; Liu, Guangbo; Cao, Wenwu; Pantelides, Sokrates T.; Zhou, Wu; et al

    2016-07-19

    2D layered MoS2 has drawn intense attention for its applications in flexible electronic, optoelectronic, and spintronic devices. Most of the MoS2 atomic layers grown by conventional chemical vapor deposition techniques are n-type due to the abundant sulfur vacancies. Facile production of MoS2 atomic layers with p-type behavior, however, remains challenging. Here, a novel one-step growth has been developed to attain p-type MoS2 layers in large scale by using Mo-containing sol–gel, including 1% tungsten (W). Atomic-resolution electron microscopy characterization reveals that small tungsten oxide clusters are commonly present on the as-grown MoS2 film due to the incomplete reduction of W precursormore » at the reaction temperature. These omnipresent small tungsten oxide clusters contribute to the p-type behavior, as verified by density functional theory calculations, while preserving the crystallinity of the MoS2 atomic layers. The Mo containing sol–gel precursor is compatible with the soft-lithography techniques, which enables patterned growth of p-type MoS2 atomic layers into regular arrays with different shapes, holding great promise for highly integrated device applications. Lastly, an atomically thin p–n junction is fabricated by the as-prepared MoS2, which shows strong rectifying behavior.« less

  1. Spatially nonrandom tree mortality and ingrowth maintain equilibrium pattern in an old-growth Pseudotsuga-Tsuga forest.

    PubMed

    Lutz, James A; Larson, Andrew J; Furniss, Tucker J; Donato, Daniel C; Freund, James A; Swanson, Mark E; Bible, Kenneth J; Chen, Jiquan; Franklin, Jerry F

    2014-08-01

    Mortality processes in old-growth forests are generally assumed to be driven by gap-scale disturbance, with only a limited role ascribed to density-dependent mortality, but these assumptions are rarely tested with data sets incorporating repeated measurements. Using a 12-ha spatially explicit plot censused 13 years apart in an approximately 500-year-old Pseudotsuga-Tsuga forest, we demonstrate significant density-dependent mortality and spatially aggregated tree recruitment. However, the combined effect of these strongly nonrandom demographic processes was to maintain tree patterns in a state of dynamic equilibrium. Density-dependent mortality was most pronounced for the dominant late-successional species, Tsuga heterophylla. The long-lived, early-seral Pseudotsuga menziesii experienced an annual stem mortality rate of 0.84% and no new recruitment. Late-seral species Tsuga and Abies amabilis had nearly balanced demographic rates of ingrowth and mortality. The 2.34% mortality rate for Taxus brevifolia was higher than expected, notably less than ingrowth, and strongly affected by proximity to Tsuga. Large-diameter Tsuga structured both the regenerating conspecific and heterospecific cohorts with recruitment of Tsuga and Abies unlikely in neighborhoods crowded with large-diameter competitors (P < 0.001). Density-dependent competitive interactions strongly shape forest communities even five centuries after stand initiation, underscoring the dynamic nature of even equilibrial old-growth forests. PMID:25230456

  2. The promoter methylomes of monochorionic twin placentas reveal intrauterine growth restriction-specific variations in the methylation patterns

    PubMed Central

    He, Zhiming; Lu, Hanlin; Luo, Huijuan; Gao, Fei; Wang, Tong; Gao, Yu; Fang, Qun; Wang, Junwen

    2016-01-01

    Intrauterine growth restriction (IUGR) affects the foetus and has a number of pathological consequences throughout life. Recent work has indicated that variations in DNA methylation might cause placental dysfunction, which may be associated with adverse pregnancy complications. Here, we investigated the promoter methylomes of placental shares from seven monochorionic (MC) twins with selective intrauterine growth restriction (sIUGR) using the healthy twin as an ideal control. Our work demonstrated that the IUGR placental shares harboured a distinct DNA hypomethylation pattern and that the methylation variations preferentially occurred in CpG island shores or non-CpG island promoters. The differentially methylated promoters could significantly separate the IUGR placental shares from the healthy ones. Ultra‐performance liquid chromatography/tandem mass spectrometry (UPLC‐MS/MS) further confirmed the genome‐wide DNA hypomethylation and the lower level of hydroxymethylation statuses in the IUGR placental shares. The methylation variations of the LRAT and SLC19A1 promoters, which are involved in vitamin A metabolism and folate transportation, respectively, and the EFS promoter were further validated in an additional 12 pairs of MC twins with sIUGR. Although the expressions of LRAT, SLC19A1 and EFS were not affected, we still speculated that DNA methylation and hydroxymethylation might serve a functional role during in utero foetal development. PMID:26830322

  3. Estimation of the growth patterns of Oestrus ovis L. larvae hosted by goats in Baja California Sur, Mexico.

    PubMed

    Cepeda-Palacios, R; Avila, A; Ramírez-Orduña, R; Dorchies, P

    1999-09-30

    To estimate parameters for the variation in larval weight and dimension in Oestrus ovis L. and to describe the approximate pattern of growth, 2041 larvae were collected from 431 slaughtered goats and classified on a scale of 12 identified physiological ages, according to spiracular and integumental pigmentation. Larval live weight and measures of length, width, and thickness at the seventh segment were obtained. Weight increased from 0.23 mg in L1 larvae to 49 mg in late L2 larvae; however, the highest increases in weight were found to occur after the L2-L3 molt, especially during the early L3 period, when larvae acquired about 45% of the average mature weight (518 mg). Average larval length increased almost linearly from about 2 mm in L1 larvae to reach full length (21.3 mm) just before initiating integumental pigmentation, then it tended to stabilize until full maturation. Except for higher increases during the early L3 period, larval width and thickness increased linearly to reach mean maximum values (6.0 and 5.0 mm, respectively) at full maturity. Weight and measurement data were fitted by monophasic, s-shaped growth functions. The y = 0.25 [1 + tanh[0.504 (12-6.65)

  4. The use of substrate materials and topography to modify growth patterns and rates of differentiation of muscle cells.

    PubMed

    Murray, L M; Nock, V; Evans, J J; Alkaisi, M M

    2016-07-01

    Cells are cultured on platforms made of a variety of materials with selected topographies during studies of cell response and behavior. Understanding the effects of substrates is essential for such applications as developing effective interfaces between body cells and implanted materials and devices. In this study, the effects of substrate surface properties on cell differentiation and alignment on C2C12 myoblasts cultured on conventional or fabricated polymeric cell culture substrates were investigated. Comparisons were made between cells cultured on tissue culture grade polystyrene (TCPS), glass, Permanox, and cured polydimethylsiloxane (PDMS) substrates. Fluorescent immunohistochemistry of cell markers was used to analyse the extent of differentiation. Alignment and guidance of cell growth and spread were studied using patterned platforms. Gratings were made on polystyrene (PS) and PDMS and differentiation was facilitated after 5 days by media exchange. Differences in cell morphology were observed between cells cultured on TCPS and PDMS substrates. Fully differentiated myotubes were observed in highest numbers on TCPS substrates and were non-detectable on PDMS substrates in the time frame of 144 h. Muscle cell alignment and their differentiation followed along the grating patterns on PS and elongated along the pattern length. On the other hand, on PDMS cells formed sheets of tissue and peeled from the substrate. We have revealed the potential for the combinations of surface materials and topography on cell behavior to induce accelerated differentiation and coordinated alignment. The results demonstrate that culture environment can be designed or engineered to modify or regulate muscle cell functions. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1638-1645, 2016.

  5. Relationship between fat patterns, physical fitness and blood pressure of rural South African children: Ellisras Longitudinal Growth and Health Study.

    PubMed

    Monyeki, K D; Kemper, H C G; Makgae, P J

    2008-05-01

    The present study investigated the relationship between blood pressure (BP), fat patterns and fitness parameters of Ellisras children aged 7-13 years. Furthermore, an assessment of body fat patterns was done to determine the subjects with the highest risk of overweight, hypertension and waist-to-hip ratio above the 90th percentile. Data were collected from 1,817 subjects (938 boys and 879 girls), aged 7-13 years, participating in the Ellisras Longitudinal Study. Anthropometric measurements were taken according to the standard procedure of the International Society for the Advancement of Kinanthropometry. The EUROFIT test items were used to test the physical fitness of 1,192 subjects (634 boys and 558 girls). Obesity was defined using the international recommended cutoff points for body mass index (BMI) in children. Hypertension was defined as the occurrence of BP levels greater or equal to the 95th percentile of height- and sex-adjusted reference levels. The prevalence of hypertension ranged from 1 to 11.4% and that of overweight 0.6-4.6%. Waist girth, BMI, triceps and subscapular skinfold showed significant (P<0.001-0.05) correlation with other fat pattern parameters (r ranging from -0.157 to 0.978) compared with significant correlations (P<0.001-0.05) with BP (r ranging from -0.071 to 0.164). Children with waist girth greater than the 90th percentile are more likely to have multiple risk factors than the children with a waist girth that is less than or equal to the 90th percentile. Longitudinal studies should verify whether changes in waist girth and skinfolds will indicate changes in cardiovascular risk factors during growth.

  6. Parathyroid hormone secretory pattern, circulating activity, and effect on bone turnover in adult growth hormone deficiency.

    PubMed

    Ahmad, A M; Hopkins, M T; Fraser, W D; Ooi, C G; Durham, B H; Vora, J P

    2003-02-01

    Adult growth hormone deficiency (AGHD) is associated with osteoporosis. Reports have associated parathyroid hormone (PTH) circadian rhythm abnormalities with osteoporosis. Furthermore, there is evidence of relative PTH insensitivity in AGHD patients. Factors regulating PTH circadian rhythm are not fully understood. There is evidence that serum phosphate is a likely determinant of PTH rhythm. The aim of this study was to investigate PTH circadian rhythm and its circulating activity and association with bone turnover in untreated AGHD patients compared to healthy individuals. We sampled peripheral venous blood at 30-min and urine at 3-h intervals during the day over a 24-h period from 1400 h in 14 untreated AGHD patients (7 M, 7 W; mean age, 49.5 +/- 10.7 years) and 14 age (48.6 +/- 11.4 years; P = NS) and gender-matched controls. Cosinor analysis was performed to analyze rhythm parameters. Cross-correlational analysis was used to determine the relationship between variables. Serum PTH (1-84), phosphate, total calcium, urea, creatinine, albumin, type I collagen C-telopeptides (CT(x)), a bone resorption marker, and procollagen type I amino-terminal propeptide (PINP), a bone formation marker, were measured on all samples. Nephrogenous cyclic adenosine monophosphate (NcAMP), which reflects the renal activity of PTH, was calculated from plasma and urinary cAMP. Urinary calcium and phosphate were measured on all urine samples. Significant circadian rhythms were observed for serum PTH, phosphate, CT(x), and PINP in AGHD and healthy subjects (P < 0.001). No significant rhythm was observed for serum-adjusted calcium. PTH MESOR (rhythm-adjusted mean) was significantly higher (P < 0.05), whereas the MESOR values for phosphate, CT(x) (P < 0.05), and PINP (P < 0.001) were lower in AGHD patients than in controls. AGHD patients had significantly lower 24-h NcAMP (P < 0.001) and higher urinary calcium excretion (P < 0.05). Maximum cross-correlation between PTH and phosphate (r = 0

  7. Summer global atmospheric patterns enhanced the Mediterranean East-West differences on tree growth at rear-edge temperate deciduous forests

    NASA Astrophysics Data System (ADS)

    Dorado Liñán, Isabel; Zorita, Eduardo; Gea-Izquierdo, Guillermo; Martínez-Sancho, Elisabet; Levanic, Tom; Zlatanov, Tzvetan; Di Filippo, Alfredo; Zang, Christian; Gutiérrez, Emilia; Menzel, Annette

    2016-04-01

    Overlaid to a general decrease on European beech and Sessile oak tree growth over the recent decades in the Mediterranean Basin, tree-ring records from western populations display a stronger growth decrease than eastern populations. We investigate here to what extent this spatial pattern of tree growth can be explained by the impact of sustained atmospheric circulation patterns in summertime. We use Canonical Correlation Analysis, a statistical method that identifies the patterns of two multivariate variables that are optimally correlated. A generalized change in growth trends, turning from a general increase during the period 1950-1981 to a generalized decrease in growth observed during the last three decades can be attributed to increasing summer temperatures, which exerts a dominant and negative influence on tree growth across sites. However, summer precipitation has gained in importance coinciding with the intensification of the geographical differences in tree sensitivity across the Mediterranean Basin. This intensification of the geographical differences in tree- growth during the last three decades can be traced back to an intensification of the Summer North Atlantic Oscillation that imparts an east-west dipole in summer precipitation. Under persistent positive SNAO, western populations are expected to face harsher summer conditions than central and eastern rear-edge populations, due to stronger decrease of precipitation in the west Mediterranean Basin. This increase in xericity will likely be negative for temperate deciduous broadleaf species at the rear-edge of their distribution in the Mediterranean Basin.

  8. Automated Patent Categorization and Guided Patent Search using IPC as Inspired by MeSH and PubMed.

    PubMed

    Eisinger, Daniel; Tsatsaronis, George; Bundschus, Markus; Wieneke, Ulrich; Schroeder, Michael

    2013-04-15

    Document search on PubMed, the pre-eminent database for biomedical literature, relies on the annotation of its documents with relevant terms from the Medical Subject Headings ontology (MeSH) for improving recall through query expansion. Patent documents are another important information source, though they are considerably less accessible. One option to expand patent search beyond pure keywords is the inclusion of classification information: Since every patent is assigned at least one class code, it should be possible for these assignments to be automatically used in a similar way as the MeSH annotations in PubMed. In order to develop a system for this task, it is necessary to have a good understanding of the properties of both classification systems. This report describes our comparative analysis of MeSH and the main patent classification system, the International Patent Classification (IPC). We investigate the hierarchical structures as well as the properties of the terms/classes respectively, and we compare the assignment of IPC codes to patents with the annotation of PubMed documents with MeSH terms.Our analysis shows a strong structural similarity of the hierarchies, but significant differences of terms and annotations. The low number of IPC class assignments and the lack of occurrences of class labels in patent texts imply that current patent search is severely limited. To overcome these limits, we evaluate a method for the automated assignment of additional classes to patent documents, and we propose a system for guided patent search based on the use of class co-occurrence information and external resources.

  9. Automated Patent Categorization and Guided Patent Search using IPC as Inspired by MeSH and PubMed

    PubMed Central

    2013-01-01

    Document search on PubMed, the pre-eminent database for biomedical literature, relies on the annotation of its documents with relevant terms from the Medical Subject Headings ontology (MeSH) for improving recall through query expansion. Patent documents are another important information source, though they are considerably less accessible. One option to expand patent search beyond pure keywords is the inclusion of classification information: Since every patent is assigned at least one class code, it should be possible for these assignments to be automatically used in a similar way as the MeSH annotations in PubMed. In order to develop a system for this task, it is necessary to have a good understanding of the properties of both classification systems. This report describes our comparative analysis of MeSH and the main patent classification system, the International Patent Classification (IPC). We investigate the hierarchical structures as well as the properties of the terms/classes respectively, and we compare the assignment of IPC codes to patents with the annotation of PubMed documents with MeSH terms. Our analysis shows a strong structural similarity of the hierarchies, but significant differences of terms and annotations. The low number of IPC class assignments and the lack of occurrences of class labels in patent texts imply that current patent search is severely limited. To overcome these limits, we evaluate a method for the automated assignment of additional classes to patent documents, and we propose a system for guided patent search based on the use of class co-occurrence information and external resources. PMID:23734562

  10. Development of a PubMed Based Search Tool for Identifying Sex and Gender Specific Health Literature

    PubMed Central

    Song, Michael M.; Simonsen, Cheryl K.; Wilson, Joanna D.

    2016-01-01

    Abstract Background: An effective literature search strategy is critical to achieving the aims of Sex and Gender Specific Health (SGSH): to understand sex and gender differences through research and to effectively incorporate the new knowledge into the clinical decision making process to benefit both male and female patients. The goal of this project was to develop and validate an SGSH literature search tool that is readily and freely available to clinical researchers and practitioners. Methods: PubMed, a freely available search engine for the Medline database, was selected as the platform to build the SGSH literature search tool. Combinations of Medical Subject Heading terms, text words, and title words were evaluated for optimal specificity and sensitivity. The search tool was then validated against reference bases compiled for two disease states, diabetes and stroke. Results: Key sex and gender terms and limits were bundled to create a search tool to facilitate PubMed SGSH literature searches. During validation, the search tool retrieved 50 of 94 (53.2%) stroke and 62 of 95 (65.3%) diabetes reference articles selected for validation. A general keyword search of stroke or diabetes combined with sex difference retrieved 33 of 94 (35.1%) stroke and 22 of 95 (23.2%) diabetes reference base articles, with lower sensitivity and specificity for SGSH content. Conclusions: The Texas Tech University Health Sciences Center SGSH PubMed Search Tool provides higher sensitivity and specificity to sex and gender specific health literature. The tool will facilitate research, clinical decision-making, and guideline development relevant to SGSH. PMID:26555409

  11. Pharmacy journal abstracts published in PubMed that abide by the CONsolidated Standards Of Reporting Trials (CONSORT) guidelines.

    PubMed

    Blair, Daniel A; Hughes, Peter J; Woolley, Thomas W

    2014-04-01

    The purpose of this research was to determine the proportion of abstracts in pharmacy journals that are prepared according to the CONsolidated Standards Of Reporting Trials (CONSORT) criteria for abstracts. Certain abstracts for randomized controlled clinical trials (RCTs) indexed in PubMed were eligible for inclusion, with the primary endpoint being median overall compliance to CONSORT recommendations for abstracts. A total of 63 RCT abstracts were included in the analysis, with only 56% of the recommended CONSORT items represented in the sample. It is recommended that pharmacy journals encourage authors to follow CONSORT recommendations for abstracts when submitting RCTs for publication.

  12. Tuning the Growth Pattern in 2D Confinement Regime of Sm2O3 and the Emerging Room Temperature Unusual Superparamagnetism

    PubMed Central

    Guria, Amit K.; Dey, Koushik; Sarkar, Suresh; Patra, Biplab K.; Giri, Saurav; Pradhan, Narayan

    2014-01-01

    Programming the reaction chemistry for superseding the formation of Sm2O3 in a competitive process of formation and dissolution, the crystal growth patterns are varied and two different nanostructures of Sm2O3 in 2D confinement regime are designed. Among these, the regular and self-assembled square platelets nanostructures exhibit paramagnetic behavior analogous to the bulk Sm2O3. But, the other one, 2D flower like shaped nanostructure, formed by irregular crystal growth, shows superparamagnetism at room temperature which is unusual for bulk paramagnet. It has been noted that the variation in the crystal growth pattern is due to the difference in the binding ability of two organic ligands, oleylamine and oleic acid, used for the synthesis and the magnetic behavior of the nanostructures is related to the defects incorporated during the crystal growth. Herein, we inspect the formation chemistry and plausible origin of contrasting magnetism of these nanostructures of Sm2O3. PMID:25269458

  13. Patterned growth of single-crystal 3, 4, 9, 10-perylenetetracarboxylic dianhydride nanowire arrays for field-emission and optoelectronic devices.

    PubMed

    Pan, Huanhuan; Zhang, Xiujuan; Yang, Yang; Shao, Zhibin; Deng, Wei; Ding, Ke; Zhang, Yu; Jie, Jiansheng

    2015-07-24

    3, 4, 9, 10-perylenetetracarboxylic dianhydride (PTCDA) organic nanostructures possess extraordinary electronic and optoelectronic properties. However, it remains a challenge to achieve patterned growth of PTCDA nanowire (NW) arrays for integrated device applications. Here, we demonstrated the high-density, large-area, uniform, and cross-aligned growth of single-crystalline PTCDA NW arrays by using Au nanoparticles (NPs) as the growth templates. The high surface energy of Au NPs led to the cross-aligned growth of organic NWs, enabling the growth of PTCDA NW arrays with any desirable patterns by pre-patterning the Au films on a Si substrate. The PTCDA NW arrays as field emitters show good performance with a large emission current density and high emission stability. Furthermore, photodetectors based on PTCDA NW arrays were constructed via a simple in-situ growth approach, which exhibited high sensitivity to a wideband light ranging from 400-800 nm and surpassed the individual NW-based photodetectors in terms of higher photocurrent and faster response speed. Successful applications of PTCDA NW arrays in field emission and photodetectors show a great potential application of organic NW arrays in future efficient electronic and optoelectronic devices. PMID:26135069

  14. Growth pattern differences of captive born Antillean manatee (Trichechus manatus) calves and those rescued in the Brazilian northeastern coast.

    PubMed

    Borges, João Carlos Gomes; Freire, Augusto Carlos da Bôaviagem; Attademo, Fernanda Loffler Niemeyer; Serrano, Inês de Lima; Anzolin, Daiane Garcia; de Carvalho, Paulo Sérgio Martins; Vergara-Parente, Jociery Einhardt

    2012-09-01

    The aim of this work was to analyze whether there are differences between the development pattern of Antillean manatee (Trichechus manatus) calves born in captivity and those rescued and kept under rehabilitation. Biometrics data were collected from 1990 to 2010 from 38 calves, 29 of which still had the remnants of the umbilical cord and had been rescued from the Brazilian northeastern coastline (Group I), and nine individuals that were born in captivity and remained with their mothers (Group II). Among the measures obtained through biometry, the total length and weight of the animal were recorded. Given that the breastfeeding of calves occurs approximately until the age of 2 yr, data obtained until the 24th month of life of each individual were evaluated. An average increase in weight of 53.50 +/- 38.54 kg (mean +/- standard deviation [SD]) was detected in Group I and a gain of 106.87 +/- 47.21 kg (mean +/- SD) in Group II. From months 13 to 24, no significant difference in the weight increment was observed. A similar pattern occurred with regard to the increase in the overall length during the first year, where animals from Group I grew 34.81 +/- 17.94 cm (mean +/- SD) and from Group II grew 83.83 +/- 28.21 cm, a statistically significant difference. The growth was not significantly different from 13 to 24 mo. The results found in this study identified the need for a review of the nutritional diet offered to orphaned calves rescued and kept in captivity. The results also support the need for a better adequacy of facilities for these animals as a way to encourage the management strategies adopted for manatee calves maintained in captivity.

  15. Comparison of growth patterns of subcutaneous fat tissue in Mexican and Polish with US and Peruvian populations.

    PubMed

    Wolanski, N

    1998-01-01

    The development of subcutaneous fat tissue in the US was found to follow the following stages: preschool loss, prepubertal gain, adolescent loss, stabilization, adult gain, and after top fatness, age loss. 1208 subjects 2-80 years old were studied in Maya a mixed population from Merida and Progreso (Yucatan, Mexico) measuring two fatfolds. A population of 7924 from Polish towns and villages was chosen measuring 10 fatfolds. The same pattern of fatfolds growth was found in different ethnic groups, except level of thickness and age at turning points. Adolescent loss is characteristic only for boys, and stabilization for girls. The pattern was clearly expressed in females but was only slightly marked in Yucatan males and in Poles. Data was compared for triceps fatfold, and also for the summation of several fatfolds, sometimes different in the studied populations (from 2 to 10 sites was measured). Preschool loss was mainly found at 2-5 years of age, prepubertal gain at 7-10 years, adolescent loss in boys at 11-15 years, stabilization in girls at 15-20 years, adult gain at 17-45 years, top fatness in various populations occurred between 45 and 55 years of age and next age loss was observed. Most scanty fat tissue occurred in the Peru Nunoa population, next in the Poles and white and black Americans, fat tissues became more abundant in the Mexican American and Puerto Rican, and was most abundant in the Yucatecan population. US black females have thicker fatfold than white, but white males thicker than black. Differences in amount of fat tissue are probably related to nutritional levels (quantity) and habits (quality). PMID:9741489

  16. Empowering a mesophilic inoculum for thermophilic nitrification: Growth mode and temperature pattern as critical proliferation factors for archaeal ammonia oxidizers.

    PubMed

    Courtens, Emilie N P; Vandekerckhove, Tom; Prat, Delphine; Vilchez-Vargas, Ramiro; Vital, Marius; Pieper, Dietmar H; Meerbergen, Ken; Lievens, Bart; Boon, Nico; Vlaeminck, Siegfried E

    2016-04-01

    Cost-efficient biological treatment of warm nitrogenous wastewaters requires the development of thermophilic nitrogen removal processes. Only one thermophilic nitrifying bioreactor was described so far, achieving 200 mg N L(-1) d(-1) after more than 300 days of enrichment from compost samples. From the practical point of view in which existing plants would be upgraded, however, a more time-efficient development strategy based on mesophilic nitrifying sludge is preferred. This study evaluated the adaptive capacities of mesophilic nitrifying sludge for two linear temperature increase patterns (non-oscillating vs. oscillating), two different slopes (0.25 vs. 0.08 °C d(-1)) and two different reactor types (floc vs. biofilm growth). The oscillating temperature pattern (0.25 °C d(-1)) and the moving bed biofilm reactor (0.08 °C d(-1)) could not reach nitrification at temperatures higher than 46 °C. However, nitrification rates up to 800 mg N L(-1) d(-1) and 150 mg N g(-1) volatile suspended solids d(-1) were achieved at a temperature as high as 49 °C by imposing the slowest linear temperature increase to floccular sludge. Microbial community analysis revealed that this successful transition was related with a shift in ammonium oxidizing archaea dominating ammonia oxidizing bacteria, while for nitrite oxidation Nitrospira spp. was constantly more abundant than Nitrobacter spp.. This observation was accompanied with an increase in observed sludge yield and a shift in maximal optimum temperature, determined with ex-situ temperature sensitivity measurements, predicting an upcoming reactor failure at higher temperature. Overall, this study achieved nitrification at 49 °C within 150 days by gradual adaptation of mesophilic sludge, and showed that ex-situ temperature sensitivity screening can be used to monitor and steer the transition process. PMID:26841233

  17. Contrasting Spatial Patterns in Active-Fire and Fire-Suppressed Mediterranean Climate Old-Growth Mixed Conifer Forests

    PubMed Central

    Fry, Danny L.; Stephens, Scott L.; Collins, Brandon M.; North, Malcolm P.; Franco-Vizcaíno, Ernesto; Gill, Samantha J.

    2014-01-01

    In Mediterranean environments in western North America, historic fire regimes in frequent-fire conifer forests are highly variable both temporally and spatially. This complexity influenced forest structure and spatial patterns, but some of this diversity has been lost due to anthropogenic disruption of ecosystem processes, including fire. Information from reference forest sites can help management efforts to restore forests conditions that may be more resilient to future changes in disturbance regimes and climate. In this study, we characterize tree spatial patterns using four-ha stem maps from four old-growth, Jeffrey pine-mixed conifer forests, two with active-fire regimes in northwestern Mexico and two that experienced fire exclusion in the southern Sierra Nevada. Most of the trees were in patches, averaging six to 11 trees per patch at 0.007 to 0.014 ha−1, and occupied 27–46% of the study areas. Average canopy gap sizes (0.04 ha) covering 11–20% of the area were not significantly different among sites. The putative main effects of fire exclusion were higher densities of single trees in smaller size classes, larger proportion of trees (≥56%) in large patches (≥10 trees), and decreases in spatial complexity. While a homogenization of forest structure has been a typical result from fire exclusion, some similarities in patch, single tree, and gap attributes were maintained at these sites. These within-stand descriptions provide spatially relevant benchmarks from which to manage for structural heterogeneity in frequent-fire forest types. PMID:24586472

  18. Contrasting spatial patterns in active-fire and fire-suppressed Mediterranean climate old-growth mixed conifer forests.

    PubMed

    Fry, Danny L; Stephens, Scott L; Collins, Brandon M; North, Malcolm P; Franco-Vizcaíno, Ernesto; Gill, Samantha J

    2014-01-01

    In Mediterranean environments in western North America, historic fire regimes in frequent-fire conifer forests are highly variable both temporally and spatially. This complexity influenced forest structure and spatial patterns, but some of this diversity has been lost due to anthropogenic disruption of ecosystem processes, including fire. Information from reference forest sites can help management efforts to restore forests conditions that may be more resilient to future changes in disturbance regimes and climate. In this study, we characterize tree spatial patterns using four-ha stem maps from four old-growth, Jeffrey pine-mixed conifer forests, two with active-fire regimes in northwestern Mexico and two that experienced fire exclusion in the southern Sierra Nevada. Most of the trees were in patches, averaging six to 11 trees per patch at 0.007 to 0.014 ha(-1), and occupied 27-46% of the study areas. Average canopy gap sizes (0.04 ha) covering 11-20% of the area were not significantly different among sites. The putative main effects of fire exclusion were higher densities of single trees in smaller size classes, larger proportion of trees (≥ 56%) in large patches (≥ 10 trees), and decreases in spatial complexity. While a homogenization of forest structure has been a typical result from fire exclusion, some similarities in patch, single tree, and gap attributes were maintained at these sites. These within-stand descriptions provide spatially relevant benchmarks from which to manage for structural heterogeneity in frequent-fire forest types.

  19. Growth pattern differences of captive born Antillean manatee (Trichechus manatus) calves and those rescued in the Brazilian northeastern coast.

    PubMed

    Borges, João Carlos Gomes; Freire, Augusto Carlos da Bôaviagem; Attademo, Fernanda Loffler Niemeyer; Serrano, Inês de Lima; Anzolin, Daiane Garcia; de Carvalho, Paulo Sérgio Martins; Vergara-Parente, Jociery Einhardt

    2012-09-01

    The aim of this work was to analyze whether there are differences between the development pattern of Antillean manatee (Trichechus manatus) calves born in captivity and those rescued and kept under rehabilitation. Biometrics data were collected from 1990 to 2010 from 38 calves, 29 of which still had the remnants of the umbilical cord and had been rescued from the Brazilian northeastern coastline (Group I), and nine individuals that were born in captivity and remained with their mothers (Group II). Among the measures obtained through biometry, the total length and weight of the animal were recorded. Given that the breastfeeding of calves occurs approximately until the age of 2 yr, data obtained until the 24th month of life of each individual were evaluated. An average increase in weight of 53.50 +/- 38.54 kg (mean +/- standard deviation [SD]) was detected in Group I and a gain of 106.87 +/- 47.21 kg (mean +/- SD) in Group II. From months 13 to 24, no significant difference in the weight increment was observed. A similar pattern occurred with regard to the increase in the overall length during the first year, where animals from Group I grew 34.81 +/- 17.94 cm (mean +/- SD) and from Group II grew 83.83 +/- 28.21 cm, a statistically significant difference. The growth was not significantly different from 13 to 24 mo. The results found in this study identified the need for a review of the nutritional diet offered to orphaned calves rescued and kept in captivity. The results also support the need for a better adequacy of facilities for these animals as a way to encourage the management strategies adopted for manatee calves maintained in captivity. PMID:23082512

  20. Empowering a mesophilic inoculum for thermophilic nitrification: Growth mode and temperature pattern as critical proliferation factors for archaeal ammonia oxidizers.

    PubMed

    Courtens, Emilie N P; Vandekerckhove, Tom; Prat, Delphine; Vilchez-Vargas, Ramiro; Vital, Marius; Pieper, Dietmar H; Meerbergen, Ken; Lievens, Bart; Boon, Nico; Vlaeminck, Siegfried E

    2016-04-01

    Cost-efficient biological treatment of warm nitrogenous wastewaters requires the development of thermophilic nitrogen removal processes. Only one thermophilic nitrifying bioreactor was described so far, achieving 200 mg N L(-1) d(-1) after more than 300 days of enrichment from compost samples. From the practical point of view in which existing plants would be upgraded, however, a more time-efficient development strategy based on mesophilic nitrifying sludge is preferred. This study evaluated the adaptive capacities of mesophilic nitrifying sludge for two linear temperature increase patterns (non-oscillating vs. oscillating), two different slopes (0.25 vs. 0.08 °C d(-1)) and two different reactor types (floc vs. biofilm growth). The oscillating temperature pattern (0.25 °C d(-1)) and the moving bed biofilm reactor (0.08 °C d(-1)) could not reach nitrification at temperatures higher than 46 °C. However, nitrification rates up to 800 mg N L(-1) d(-1) and 150 mg N g(-1) volatile suspended solids d(-1) were achieved at a temperature as high as 49 °C by imposing the slowest linear temperature increase to floccular sludge. Microbial community analysis revealed that this successful transition was related with a shift in ammonium oxidizing archaea dominating ammonia oxidizing bacteria, while for nitrite oxidation Nitrospira spp. was constantly more abundant than Nitrobacter spp.. This observation was accompanied with an increase in observed sludge yield and a shift in maximal optimum temperature, determined with ex-situ temperature sensitivity measurements, predicting an upcoming reactor failure at higher temperature. Overall, this study achieved nitrification at 49 °C within 150 days by gradual adaptation of mesophilic sludge, and showed that ex-situ temperature sensitivity screening can be used to monitor and steer the transition process.

  1. Fungal growth pattern, sources and factors of mould contamination in a dry-cured meat production facility.

    PubMed

    Asefa, Dereje T; Kure, Cathrine F; Gjerde, Ragnhild O; Omer, Mohamed K; Langsrud, Solveig; Nesbakken, Truls; Skaar, Ida

    2010-06-15

    The aims of this study were to investigate the patterns of fungal growth on dry-cured meat products, identify the important sources and factors of contamination and recommend intervention measures. The production processes of two smoked dry-cured hams and one unsmoked dry-cured leg of lamb were studied. A longitudinal observational study was performed to collect 642 samples from the meat, production materials, room installations and indoor and outdoor air of the production facility. Standard mycological isolation and identification procedures were followed. Totally, 901 fungal isolates were obtained; of which 57% were moulds while 43% were yeast. Yeasts were dominant on meat surfaces by covering 64% of the isolates. Mould growth was not observed until late in the dry-ripening stage. Yeasts and moulds were isolated from half of the environmental samples, of which moulds contributed by 80%. More than 39 mould species were isolated from the entire production process with a 77% contribution by the species of Penicillium. Penicillium nalgiovense dominated the species composition of moulds isolated from the products and the production environment. A preliminary bioassay analysis on bacterial colonies indicated that most of the P. nalgiovense isolates have the ability to produce penicillin. Such isolates might produce penicillin on the products and can become potential food safety hazards. Improper pressing at the salting process, the air quality in salting, brining and smoking rooms and activities in the sorting room were identified as important factors and sources of fungal contamination. Technical solutions and organized production activities that reduce crack formation, airborne spore concentration and improve air circulation in the facility are recommended as intervention measures.

  2. Improved large-scale prediction of growth inhibition patterns using the NCI60 cancer cell line panel

    PubMed Central

    Cortés-Ciriano, Isidro; van Westen, Gerard J. P.; Bouvier, Guillaume; Nilges, Michael; Overington, John P.; Bender, Andreas; Malliavin, Thérèse E.

    2016-01-01

    Motivation: Recent large-scale omics initiatives have catalogued the somatic alterations of cancer cell line panels along with their pharmacological response to hundreds of compounds. In this study, we have explored these data to advance computational approaches that enable more effective and targeted use of current and future anticancer therapeutics. Results: We modelled the 50% growth inhibition bioassay end-point (GI50) of 17 142 compounds screened against 59 cancer cell lines from the NCI60 panel (941 831 data-points, matrix 93.08% complete) by integrating the chemical and biological (cell line) information. We determine that the protein, gene transcript and miRNA abundance provide the highest predictive signal when modelling the GI50 endpoint, which significantly outperformed the DNA copy-number variation or exome sequencing data (Tukey’s Honestly Significant Difference, P <0.05). We demonstrate that, within the limits of the data, our approach exhibits the ability to both interpolate and extrapolate compound bioactivities to new cell lines and tissues and, although to a lesser extent, to dissimilar compounds. Moreover, our approach outperforms previous models generated on the GDSC dataset. Finally, we determine that in the cases investigated in more detail, the predicted drug-pathway associations and growth inhibition patterns are mostly consistent with the experimental data, which also suggests the possibility of identifying genomic markers of drug sensitivity for novel compounds on novel cell lines. Contact: terez@pasteur.fr; ab454@ac.cam.uk Supplementary information: Supplementary data are available at Bioinformatics online. PMID:26351271

  3. Patterns of trunk spine growth in two congeneric species of acanthocephalan: investment in attachment may differ between sexes and species.

    PubMed

    Hernández-Orts, Jesús S; Timi, Juan T; Raga, Juan A; García-Varela, M; Crespo, Enrique A; Aznar, Francisco J

    2012-06-01

    Acanthocephalans have evolved a hooked proboscis and some taxa have trunk spines to attach to their definitive hosts. These structures are generated before being used, thus a key question is how investment in attachment could optimally be allocated through the ontogeny. The number and arrangement of hooks and spines are never modified in the definitive host, but it is unclear whether these structures grow during adult development. A comparison of the size of trunk spines between cystacanths and adults of Corynosoma cetaceum and C. australe indicated that spines grow in both species, but only in females, which also had significantly larger spines than males. This sexual dimorphism did not result from pure allometry because the body of females was smaller, and did not grow more than that of males. However, having a longer lifespan, females would need to withstand the extreme flow conditions prevailing in marine mammals for longer, inducing different investment and development schedules for spines. Patterns of spine growth also differed between species: fore-trunk spines grew in both species, but hind-trunk spines did only in C. cetaceum. In conclusion, investment strategies on attachment may differ, not only between congeneric species of acanthocephalan, but also between sexes of the same species. PMID:22309658

  4. Patterns of growth and body condition in sea otters from the Aleutian archipelago before and after the recent population decline

    USGS Publications Warehouse

    Laidre, K.L.; Estes, J.A.; Tinker, M.T.; Bodkin, J.; Monson, D.; Schneider, K.

    2006-01-01

    3In addition to larger asymptotic values for mass and length, the rate of growth towards asymptotic values was more rapid in the 1990s than in the 1960s/70s: sea otters reached 95% of asymptotic body mass and body length 1–2 years earlier in the 1990s.4Body condition (as measured by the log mass/log length ratio) was significantly greater in males than in females. There was also an increasing trend from the 1960s/70s through 2004 despite much year-to-year variation.5Population age structures differed significantly between the 1960s/70s and the 1990s with the latter distribution skewed toward younger age classes (indicating an altered lxfunction) suggesting almost complete relaxation of age-dependent mortality patterns (i.e. those typical of food-limited populations).6This study spanned a period of time over which the population status of sea otters in the Aleutian archipelago declined precipitously from levels at or near equilibrium densities at some islands in the 1960s/70s to < 5% of estimated carrying capacity by the late 1990s. The results of this study indicate an improved overall health of sea otters over the period of decline and suggest that limited nutritional resources were not the cause of the observed reduced population abundance. Our findings are consistent with the hypothesis that the decline was caused by increased killer whale predation.

  5. Placental Expression Patterns of Galectin-1, Galectin-2, Galectin-3 and Galectin-13 in Cases of Intrauterine Growth Restriction (IUGR)

    PubMed Central

    Hutter, Stefan; Knabl, Julia; Andergassen, Ulrich; Hofmann, Simone; Kuhn, Christina; Mahner, Sven; Arck, Petra; Jeschke, Udo

    2016-01-01

    Galectins (gal) are members of the mammalian β-galactoside-binding proteins and recognize Galβ1-4GlcNAc and Galβ1-4GalNac (Thomsen-Friedenreich antigen (TF)) sequences of several cell surface oligosaccharides. In this study, gal-1, -2, -3 and -13 were investigated systematically in the trophoblast and decidua compartment of intrauterine growth restriction (IUGR) placentas and normal third trimester control placentas and stratified by fetal gender and gestational age. Within this study, 29 third trimester placentas after delivery were analyzed. Fetal gender was equally divided within both groups, and immunohistochemical staining was analyzed according to fetal gender and gestational age. Double immune-fluorescence with trophoblast-specific markers was used to identify galectin-expressing cells at the feto-maternal interface in the decidua. Gal-3 was significantly downregulated only in the extravillous trophoblast of IUGR placentas. In contrast, expressions of gal-2 and gal-13 were downregulated in both villous and extravillous trophoblast cells of IUGR placentas. In addition, gal-2 and gal-13 showed a highly correlated expression scheme in the placenta. There are significant gender-specific expression patterns for single prototype galectins with downregulation of gal-2 and gal-13 of male gender placentas in cases of IUGR. Gal-3 as the chimera type galectin shows only little gender-specific differences in expression, which disappear in IUGR cases. PMID:27070577

  6. From Plant Infectivity to Growth Patterns: The Role of Blue-Light Sensing in the Prokaryotic World.

    PubMed

    Losi, Aba; Mandalari, Carmen; Gärtner, Wolfgang

    2014-01-01

    Flavin-based photoreceptor proteins of the LOV (Light, Oxygen, and Voltage) and BLUF (Blue Light sensing Using Flavins) superfamilies are ubiquitous among the three life domains and are essential blue-light sensing systems, not only in plants and algae, but also in prokaryotes. Here we review their biological roles in the prokaryotic world and their evolution pathways. An unexpected large number of bacterial species possess flavin-based photosensors, amongst which are important human and plant pathogens. Still, few cases are reported where the activity of blue-light sensors could be correlated to infectivity and/or has been shown to be involved in the activation of specific genes, resulting in selective growth patterns. Metagenomics and bio-informatic analysis have only recently been initiated, but signatures are beginning to emerge that allow definition of a bona fide LOV or BLUF domain, aiming at better selection criteria for novel blue-light sensors. We also present here, for the first time, the phylogenetic tree for archaeal LOV domains that have reached a statistically significant number but have not at all been investigated thus far. PMID:27135492

  7. How Twitter Is Studied in the Medical Professions: A Classification of Twitter Papers Indexed in PubMed

    PubMed Central

    2013-01-01

    Background Since their inception, Twitter and related microblogging systems have provided a rich source of information for researchers and have attracted interest in their affordances and use. Since 2009 PubMed has included 123 journal articles on medicine and Twitter, but no overview exists as to how the field uses Twitter in research. Objective This paper aims to identify published work relating to Twitter within the fields indexed by PubMed, and then to classify it. This classification will provide a framework in which future researchers will be able to position their work, and to provide an understanding of the current reach of research using Twitter in medical disciplines. Methods Papers on Twitter and related topics were identified and reviewed. The papers were then qualitatively classified based on the paper’s title and abstract to determine their focus. The work that was Twitter focused was studied in detail to determine what data, if any, it was based on, and from this a categorization of the data set size used in the studies was developed. Using open coded content analysis additional important categories were also identified, relating to the primary methodology, domain, and aspect. Results As of 2012, PubMed comprises more than 21 million citations from biomedical literature, and from these a corpus of 134 potentially Twitter related papers were identified, eleven of which were subsequently found not to be relevant. There were no papers prior to 2009 relating to microblogging, a term first used in 2006. Of the remaining 123 papers which mentioned Twitter, thirty were focused on Twitter (the others referring to it tangentia